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Showing 146 of 146 peer-reviewed papers with full Graphical Abstracts.

Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202506005• Jan 15, 2026

Analysis of National and Local Policies for Medical Waste Treatment and Disposal in China

Authors: LI Mu, CHEN Yiming, WANG Jiaqing, HUANG Guanzhong, WANG Zeng, WANG Zhaolong, CHEN Weixing, GAO Wenfang

The escalating generation of medical waste, driven by healthcare expansion and frequent medical activities, poses significant environmental and public health risks. Under the framework of ecological civilization, China is developing a comprehensive policy system for medical waste treatment and disposal, yet the current framework remains nascent and exhibits inconsistencies between national and local policies. This study systematically analyzes the status of national and local policies from 2003 to 2024, collecting 413 policy documents (166 from national ministries and 247 from provincial governments). The analysis examines temporal evolution, regional distribution, and policy focus, alongside the influence of medical waste output, treatment technologies, facility infrastructure, and major epidemic responses. Findings reveal distinct policy phases: initial self-disposal, exploratory management, foundational system building, and rapid development. Regional disparities are pronounced, with eastern coastal areas showing more advanced policies due to greater technical and financial resources. The surge in medical waste, particularly during the COVID-19 pandemic, underscores the need for enhanced regulatory guidance. Non-incineration technologies are gaining traction for their environmental and cost benefits, and facility coverage has improved but remains uneven. The study proposes five policy principles to foster technological innovation and industrial upgrading, ensuring safe medical waste management and environmental protection.

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Analysis of National and Local Policies for Medical Waste Treatment and Disposal in China

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507064• Jan 15, 2026

Kinetic Analysis and Simulation of Pollutant Removal in Sewage Networks

Authors: FENG Ruodan, LI Cuimei, ZHU Chunwei, ZHOU Lifen, ZUO Shu, ZHANG Jian

This study investigates pollutant removal characteristics and kinetic behaviors in sewage networks, and analyzes their impact on the carbon-to-nitrogen ratio (C/N, as COD/TN) of influent to wastewater treatment plants. Source water quality sampling at drainage outlets revealed spatial and temporal variations in C/N, with domestic sewage exhibiting higher C/N than industrial sewage, and diurnal peaks reaching 6.92 versus 4.71 during off-peak hours. Using a pilot-scale adjustable sewage network system in Kunshan, experiments were conducted under high (0.491 m·s−1) and low (0.089 m·s−1) flow velocities, monitoring pollutant removal over 144 hours. Pseudo-first-order kinetics were applied to model COD and TN removal. Results showed that COD (including SCOD and PCOD), BOD5, and SS achieved approximately 80% removal within 144 h, with higher removal at low flow velocity. TN, NH3-N, and TP exhibited lower overall removal rates. Kinetic fitting revealed that COD removal rate constants (kCOD) were significantly higher than those for TN (kTN), and both decreased with increasing flow velocity: at low velocity, kCOD=0.0167 h−1 and kTN=0.0029 h−1; at high velocity, kCOD=0.0127 h−1 and kTN=0.0020 h−1. Simulations based on actual source pollutant concentrations indicated that the time for C/N to drop to the denitrification critical value of 4.50 was 12.24 h at high velocity, but shortened to 9.49 h at low velocity. These findings demonstrate that increasing flow velocity effectively retards the decline of C/N. Therefore, regulating network flow velocity to reduce hydraulic retention time is a key strategy for maintaining adequate C/N at the terminal and ensuring denitrification efficiency in wastewater treatment plants.

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Kinetic Analysis and Simulation of Pollutant Removal in Sewage Networks

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202506081• Jan 15, 2026

Preparation of Trimetallic-Carbon Composite Catalysts and Their Application in Catalytic Ozonation of Industrial Wastewater

Authors: CAO Xu, MEI Hong, WANG Yan, PENG Lijing, LIU Xianwei, JU

Advanced oxidation processes (AOPs) are promising for degrading organic pollutants in water treatment. Heterogeneous catalytic ozonation (HCO) has gained attention due to its high oxidation efficiency, strong interference resistance, and low secondary pollution. In this study, a series of trimetallic-carbon composite ozone catalysts were prepared via an organic precursor calcination method using γ-Al2O3 as support. This method enhanced catalytic activity and mechanical strength while overcoming the limitations of carbon materials (low mechanical strength) and metal-based materials (poor mass transfer). The optimized catalyst, CA-FeCoCu, comprising Fe, Co, Cu, carbon, and alumina, exhibited excellent performance in phenol degradation and real industrial wastewater treatment. Characterization revealed that the synergistic effect of trimetals and the introduction of multiple carbon types increased specific surface area and hydroxyl radical (·OH) generation. In a pilot-scale fixed-bed reactor, the CA-FeCoCu/O3 system reduced COD from 120 mg·L−1 to below 40 mg·L−1, with an O3 consumption ratio (O/C) of less than 1, effectively lowering operational costs. This work provides a new strategy for developing efficient and stable heterogeneous O3 catalysts and offers a reference for the practical application of HCO in industrial wastewater treatment.

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Preparation of Trimetallic-Carbon Composite Catalysts and Their Application in Catalytic Ozonation of Industrial Wastewater

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507085• Jan 15, 2026

Differentiated Characteristics of Suspended Particulate Matter and Their Effects on Water Quality in the Middle and East Routes of the South-to-North Water Diversion Project

Authors: ZHANG Junzhi, CHEN Borong, DONG Chenyu, CHANG Zhibing, ZHONG Mingyuan, ZHU Wenhao, YU Jianwei, ZHANG Honggang

This study investigates the spatiotemporal differentiation of suspended particulate matter (SPM) characteristics, sources, and their impacts on water quality between the Middle Route (closed artificial channel) and East Route (open natural water system) of the South-to-North Water Diversion Project. Thirty sampling sites (13 on the Middle Route, 17 on the East Route) were established, and samples were collected during dry and wet seasons. Water quality parameters and SPM characteristics were analyzed, including particle size distribution, total suspended solids (TSS), chlorophyll a, and stable carbon and nitrogen isotopes. Results show that the Middle Route maintains good and stable water quality, with SPM dominated by coarse particles (>63 μm, 61.43%–94.68%), total phosphorus (TP) <0.01 mg·L−1, and a significant positive correlation between chlorophyll a and coarse particles (r=0.60), indicating algal aggregation dominates particle formation. In contrast, the East Route exhibits high and fluctuating nitrogen and phosphorus concentrations, with SPM dominated by fine particles (<20 μm, 51.26%–88.61%), TP ranging from 0.03 to 1.11 mg·L−1, and a positive correlation with fine particles, suggesting significant external inputs. Carbon and nitrogen isotope analysis reveals that Middle Route SPM primarily originates from autochthonous algae (contribution >46.75%), while East Route SPM is influenced by both terrestrial C3 plants and algae. The distinct engineering and management approaches of the two routes lead to significant differences in SPM characteristics and sources, thereby affecting water quality dynamics. The Middle Route requires an 'algal reduction and hydrodynamic optimization' strategy to control algal-derived coarse particle deposition, whereas the East Route benefits from 'retention-sedimentation and wetland purification' to reduce external fine particles and pollutant inputs. This research provides theoretical support and practical guidance for differentiated SPM management in long-distance water diversion systems.

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Differentiated Characteristics of Suspended Particulate Matter and Their Effects on Water Quality in the Middle and East Routes of the South-to-North Water Diversion Project

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507110• Jan 15, 2026

Combined Ozone Micro-Nano Bubble Oxidation and Powdered Activated Carbon Adsorption for Removal of Taste and Odor Compounds from Drinking Water

Authors: DENG Qiujin, LU Zhifeng, CHEN Ben, CHEN Sa, LIANG Qifeng, SONG Chuqi, YANG Qiujian, JIA Yanyan, LYU Hui

Algal-derived taste and odor compounds (2-methylisoborneol, 2-MIB, and geosmin, GSM) in drinking water sources are poorly removed by conventional treatment. This study systematically evaluated the standalone and combined performance of ozone micro-nano bubbles (O3-MNBs) oxidation and powdered activated carbon (PAC) adsorption for removing 2-MIB, GSM, and algal cells from source water. Results showed that O3-MNBs pre-oxidation achieved >97.5% removal of odorants at 400 ng·L−1 and 67.2% algal cell removal within 30 min. When applied as a deep treatment stage, the degradation rate constant (k) was 10.1%–25.6% higher than in pre-oxidation due to lower background matrix interference. Both pre-oxidation and deep treatment reduced effluent concentrations of 2-MIB and GSM to below 10 ng·L−1, with oxidation kinetics fitting pseudo-first-order models (R²>0.95). PAC adsorption of both compounds followed pseudo-second-order kinetics (R²>0.99), with GSM equilibrium adsorption capacity approximately 20.0% higher than that of 2-MIB. In pure water, adsorption capacity increased by >10.0% compared to raw water. Based on kinetic models, a quantitative prediction method was established for O3-MNBs oxidation and PAC adsorption processes, aiming to achieve efficient odorant removal and cost optimization, providing theoretical support for advanced drinking water purification and smart water plant construction.

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Combined Ozone Micro-Nano Bubble Oxidation and Powdered Activated Carbon Adsorption for Removal of Taste and Odor Compounds from Drinking Water

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507111• Jan 15, 2026

Pulsed Electric Field Enhancement of Nitrogen Removal Performance and Microbial Community Structure Response in Anammox Granular Sludge

Authors: WANG Xuzhong, ZHANG Ning, ZHANG Pengyu, MIAO Juan, ZHANG Ruichang, ZHOU Ming, WEI Xuefeng

This study investigated the effects of a ring-shaped pulsed electric field (PEF) (1.5 V, 4 h on-time per cycle) on nitrogen removal performance and microbial community structure of anammox granular sludge (AnGS). Two anaerobic sequencing batch reactors (R1 control, R2 with PEF) were operated under stepwise increasing nitrogen loading rates (NLR). At NLR below 1,155 mg·(L·d)−1, R2 exhibited total nitrogen removal efficiency (TRE) 7.5%–17.0% higher than R1, with biomass, specific anammox activity (SAA), and extracellular polymeric substances (EPS) increased by 5%–7%, 21%–71%, and 54%–77%, respectively. However, at NLR above 1,320 mg·(L·d)−1, the toxic effect of nitrite dominated, and PEF enhancement diminished or even reversed to inhibition. Microbial community analysis revealed that at low-to-moderate NLR, PEF increased the relative abundance of Planctomycetes and key anammox bacteria (Candidatus Brocadia and Candidatus Jettenia), along with enhanced community richness (Chao1) and diversity (Shannon/Simpson indices). At high NLR, PEF decreased microbial richness compared to R1. Principal component analysis and redundancy analysis indicated that PEF was the key factor driving community differences at low-to-moderate NLR, whereas nitrite concentration became the dominant factor at high NLR. This study provides theoretical support for enhancing the resilience and engineering application of anammox processes.

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Pulsed Electric Field Enhancement of Nitrogen Removal Performance and Microbial Community Structure Response in Anammox Granular Sludge

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202506019• Jan 15, 2026

Behavior and Mechanism of Uranium Removal from Acidic Uranium-Contaminated Groundwater by Sandstone Particle/Hydroxyapatite Composite

Authors: DING Dexin, LIU Junyu, LANG Tao, DING Yang, LI Feng, HU Nan, WANG Nieying, ZHANG Hui

Acidic in-situ leaching of sandstone-type uranium deposits leaves residual acid and uranium in groundwater, posing environmental risks. This study investigated the feasibility of loading hydroxyapatite (HAP) onto aquifer sandstone particles for in-situ remediation. Sandstone particles were collected from an aquifer and reacted with a HAP-generating solution for 52 days to produce sandstone/HAP composite. Batch experiments examined the effects of initial pH, initial uranium concentration, composite dosage, and interfering ions on uranium removal. Results showed successful HAP loading on sandstone surfaces. At initial pH 3, uranium concentration 5 mg/L, composite dosage 3 g/L, and 24 h reaction, uranium removal reached 95.6%. Interfering ions suppressed removal in the order Fe3+ > Mn2+ > Ca2+ > Mg2+ > SO4^2-. Removal mechanisms included electrostatic adsorption, ion exchange, and dissolution-reprecipitation, with good stability of immobilized uranium. This work validates the concept of in-situ HAP loading in aquifers and provides a basis for practical application in acidic uranium-contaminated groundwater remediation.

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Behavior and Mechanism of Uranium Removal from Acidic Uranium-Contaminated Groundwater by Sandstone Particle/Hydroxyapatite Composite

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507062• Jan 15, 2026

Construction of a VIKOR Composite Index-Based Probabilistic Prediction Model for Urban Water Blackening and Odor Recurrence Using Multi-Method Feature Selection

Authors: ZHANG Qi, ZHANG Jie, WANG Song, ZHOU Zhen, TANG Rui

The construction of predictive models for the recurrence of blackening and odor in urban water bodies has become a critical foundation for refined management of urban water environments. Based on water quality monitoring data from 16 cities in the Yangtze River Basin from 2020 to 2023, this study systematically evaluated six typical comprehensive index calculation methods and proposed a probabilistic prediction model for water blackening and odor recurrence centered on the VIKOR composite index. Through sampling analysis and literature review, a power-law relationship between transparency (y) and turbidity (x) was established (y = 3.12x−0.66), leading to a critical turbidity threshold of 46.9 NTU for blackening and odor. Using ANOVA, recursive feature elimination, and random forest, five indicators—turbidity, dissolved oxygen (DO), total phosphorus (TP), permanganate index (CODMn), and ammonia nitrogen (NH3-N)—were selected as the model's indicator system, with importance ranking: turbidity > DO > TP > CODMn > NH3-N. The VIKOR composite index exhibited the most robust mapping relationship with blackening probability, achieving high accuracy (RMSE = 0.029, MAE = 0.020) and consistency (NSE = 0.918, R2 = 0.918), whereas models based on other indices yielded R2 values below 0.84. The model demonstrated good predictive performance across the Yangtze, Pearl, Haihe, and Yellow River basins. This model offers a universal decision-making tool for precise identification, early warning, and targeted management of water blackening and odor recurrence, with potential integration into urban water smart platforms.

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Construction of a VIKOR Composite Index-Based Probabilistic Prediction Model for Urban Water Blackening and Odor Recurrence Using Multi-Method Feature Selection

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202506010• Jan 15, 2026

Interpretation and Implementation Recommendations for the Technical Specification for Comprehensive Utilization of Titanium Gypsum (GB/T 45015-2024)

Authors: ZHANG Dongqi, HE Yi, XU Jie, QI Xiangzhao, LI Li, CHEN Gang

To facilitate accurate understanding and implementation of the provisions in the Technical Specification for Comprehensive Utilization of Titanium Gypsum (GB/T 45015-2024), and to promote technological capability in comprehensive utilization while effectively controlling environmental risks during utilization, this paper analyzes the current status and existing problems of titanium gypsum generation, management, and utilization technologies in China. The standard is systematically interpreted. It is concluded that the implementation of this standard will promote resource utilization of titanium gypsum, foster energy conservation and carbon reduction in the titanium dioxide industry, and further safeguard ecological and environmental security. China produces over 3,120×10^4 t of titanium gypsum annually (2023), yet its comprehensive utilization rate is only about 10%, far lower than that of phosphogypsum (~40%) and desulfurization gypsum (~80%). The standard, as the first national standard dedicated to titanium gypsum resource utilization, establishes technical pathways for building materials and ecological restoration, sets limits for soluble impurities, and specifies pollution control indicators throughout the utilization process. It addresses the long-standing gaps in technical standards, product quality variability, and environmental supervision, providing critical support for the green and low-carbon transformation of the sulfuric acid process titanium dioxide industry.

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Interpretation and Implementation Recommendations for the Technical Specification for Comprehensive Utilization of Titanium Gypsum (GB/T 45015-2024)

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507054• Jan 15, 2026

Adaptability of Machine Learning Prediction Models for Chlorine Consumption to Monitoring Frequency of Residual Chlorine in Wastewater Treatment Plants

Authors: PENG Xilin, MAO Zehong, GUO Jiaxin, MA Mingliang, ZHENG Xingyu, YAO Jie, TANG Hong, YAO Juanjuan

In many Chinese wastewater treatment plants (WWTPs), residual chlorine is still manually monitored at low frequencies, leading to imprecise disinfectant dosing. This study systematically compared four machine learning models—backpropagation (BP) neural network, long short-term memory (LSTM) neural network, random forest (RF), and support vector regression (SVR)—for predicting chlorine consumption (i.e., the difference between chlorine dose and residual chlorine) during non-monitoring periods under different residual chlorine monitoring frequencies (every 1, 2, 4, 6, and 8 h). Using data from Plant A (equipped with online residual chlorine monitoring) and Plants B and C (manual monitoring every 6 h and 8 h, respectively), input variables included online water quality indicators (temperature, flow, NH3-N, CODCr, TP, TN) and chlorine dose. Results showed that at 1-h intervals, LSTM achieved the highest prediction accuracy; at 2–4-h intervals, RF performed best; at 6-h or lower frequencies, BP was superior; SVR performed worst across all frequencies. Validation on Plants B and C confirmed BP's optimal performance under low-frequency conditions, and particle swarm optimization (PSO) significantly improved its accuracy. These findings provide a basis for selecting appropriate machine learning models for chlorine consumption prediction under varying monitoring frequencies, particularly low-frequency manual monitoring, thereby supporting precise disinfectant dosing control.

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Adaptability of Machine Learning Prediction Models for Chlorine Consumption to Monitoring Frequency of Residual Chlorine in Wastewater Treatment Plants

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507041• Jan 15, 2026

Performance and Microbial Mechanisms of Aerobic Granular Sludge for Textile Dyeing Wastewater Treatment

Authors: CAO Xianzhong, LOU Huiqing, YIN Ying, SHEN Yifeng

This study investigated the cultivation of aerobic granular sludge (AGS) in a sequencing batch reactor (SBR) for the treatment of real textile dyeing wastewater, focusing on the influence of organic loading rate (OLR) on granulation and pollutant removal. After 60 days of cultivation, dense granules of approximately 1 mm diameter were formed, with extracellular polymeric substances (EPS) content of 92.22 mg·L−1, achieving COD and color removal efficiencies of 88.5% and 73.3%, respectively. OLR significantly regulated sludge characteristics: at an OLR of 3.0 kg·(m3·d)−1, the average granule size reached a maximum of 1.38 mm, EPS content peaked at 95.21 mg·g−1, and the highest COD and color removals were observed (92.73% and 86.35%, respectively). However, an excessive OLR of 5.0 kg·(m3·d)−1 led to sludge bulking and disintegration. Microbial community analysis revealed that Proteobacteria (44.06%–49.17%) and Bacteroidetes (27.49%–29.64%) were the dominant phyla, with their abundances significantly correlated with EPS protein secretion and pollutant removal efficiency. This study elucidates the mechanism by which OLR optimizes textile wastewater treatment through modulation of microbial community structure and EPS secretion, providing a theoretical basis and technical support for the practical application of AGS in textile dyeing wastewater treatment.

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Performance and Microbial Mechanisms of Aerobic Granular Sludge for Textile Dyeing Wastewater Treatment

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507059• Jan 15, 2026

Application of Immobilized White Rot Fungi in the Treatment of Anaerobic Digestion Sludge

Authors: LIU Wang, ZHU Xuefeng, WANG Ziyi, CHENG Shicai, FANG Zexian, XU Wenjing, TONG Wanzi, LIU Hongbo

Anaerobic digestion sludge (ADS) contains recalcitrant organic matter and exhibits poor dewaterability, posing challenges for disposal. This study evaluated the immobilization of white rot fungi (WRF) on four carriers—polyvinyl alcohol, cotton thread, wood chips, and sodium alginate—for ADS treatment. Cotton thread immobilization yielded the earliest and most sustained enzyme activity, highest biomass retention, and minimal biomass loss. WRF treatment achieved a 10.09% removal of total chemical oxygen demand (TCOD) and significantly disrupted extracellular polymeric substances (EPS), selectively degrading soluble EPS. To maintain fungal activity, periodic carrier replacement was required. Compared to the control, the experimental group showed an 8.9 mg·L−1 reduction in total protein and polysaccharide content in soluble EPS, a 27.33% decrease in capillary suction time (CST), and improved sludge dewaterability. These results demonstrate the potential of WRF for ADS treatment.

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Application of Immobilized White Rot Fungi in the Treatment of Anaerobic Digestion Sludge

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202508004• Jan 15, 2026

Thermoelectric Generator-Driven Electrodeposition for Efficient Treatment of Low-Concentration Copper-Containing Wastewater

Authors: HUANG Huiting, YAO Han, YANG Zhengwu, ZHU Jun, FU Dan, ZHENG Meng, JIA Daqing, ZHANG Lehua

Industrial processes generate substantial low-grade waste heat and cold, which can be harnessed via thermoelectric generators (TEGs) based on the Seebeck effect. However, the low-voltage output of TEGs poses application challenges. This study investigates a TEG-driven electrodeposition system for efficient treatment of low-concentration copper-containing wastewater from electroplating, integrated circuit, and energy industries. The TEG system, comprising two series-connected semiconductor modules, achieved a maximum power of 0.36 W at a temperature difference (ΔT) of 130 °C. Optimal operating parameters for the coupled system were determined: ΔT = 90 °C, counter-current flow (two-side inlet), flow rate of 20 mL·min⁻¹, initial Cu²⁺ concentration of 500 mg·L⁻¹, and electrode gap of 0.7 cm. Under these conditions, after 60 min of electrodeposition, copper removal efficiency reached 99.42%, current efficiency was 67.93%, and the energy conversion efficiency of the TEG-electrodeposition system was 36.96%. The system also treated real copper-containing wastewater, achieving 95.83% removal within 100 min. Characterization via SEM, XRD, and XPS revealed that the electrodeposited product consisted of metallic copper and cuprous oxide, with metallic copper accounting for approximately 60%. This work provides a promising approach for utilizing industrial waste heat and cold to achieve low-energy, high-efficiency treatment of heavy metal wastewater.

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Thermoelectric Generator-Driven Electrodeposition for Efficient Treatment of Low-Concentration Copper-Containing Wastewater

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507036• Jan 15, 2026

Integrated Barrier and Anti-Seepage Technology for Iron Tailings Pond: Application and Environmental Evaluation

Authors: XIAO Rui, CHEN Ming

This study addresses the deficiencies in material and structural stability and the singular evaluation system in iron tailings pond pollution remediation. Based on an integrated design-construction-evaluation concept, we developed a three-dimensional anti-seepage system incorporating iron tailings sand-bentonite mixtures and a composite liner structure. The system was applied to an actual remediation project in Qichun County, Hubei Province, China, covering an area of 18.72×10^4 m^2 with 43.42×10^4 m^3 of tailings. Theoretical calculations of leachate generation, material testing, and structural optimization were performed. The optimized mixture achieved a permeability coefficient (k) reduction from 10^-4 cm/s to 10^-8 cm/s as bentonite content increased from 0% to 9%, meeting the engineering standard of k≤10^-7 cm/s. A novel 'pre-embedded pipe + expansion bolt' technique enhanced sealing at structural nodes. Post-remediation monitoring showed significant reductions in heavy metal concentrations in surrounding farmland soil (11.14%–72.41% decrease), all below risk screening values. Iron (Fe) and chromium (Cr) interception rates reached 97.17% and 96.76%, respectively. The Nemerow comprehensive pollution index dropped from 2.39 (moderate pollution) to 0.62 (no pollution), and the potential ecological risk index decreased from 288.50 (moderate risk) to 148.73 (slight risk), representing a reduction of 1–3 pollution levels. The project achieved a 2.78% increase in tailings resource utilization and a 4.71% reduction in engineering cost. This integrated technical system provides a viable approach for tailings pollution control and sustainable waste management.

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Integrated Barrier and Anti-Seepage Technology for Iron Tailings Pond: Application and Environmental Evaluation

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202506041• Jan 15, 2026

Synergistic Composting of Urban and Rural Multi-Source Organic Waste and Product Quality Evaluation: A Case Study of a Treatment Center in the Taihu Lake Region

Authors: YAO Sheng, TANG Ruolan, MA Ruonan, MA Jingyuan, PAN Jiapeng, LI Ji, LI Guoxue, YUAN Jing

Urban and rural multi-source organic waste faces bottlenecks including high compositional heterogeneity, single resource recovery pathways, and uneven product quality. In the Taihu Lake region, active tourism and catering, high greening, and dense water networks generate large volumes of diverse waste with high moisture content, exacerbating these issues. This study evaluated a coupled bio-drying and aerobic composting process at a demonstration center in Linhu Town, Suzhou, Jiangsu Province, employing a three-stage control strategy: gradient dewatering, high-temperature stabilization, and maturation enhancement. Continuous operation showed that kitchen waste moisture content decreased from 77.70% to 58.69% after 1 day of bio-drying, to 23.22% after 7 days of silo reactor composting, and to 17.70% after at least 20 days of maturation. The aerobic composting phase maintained temperatures above 55°C for over 5 days, reaching a maximum of 68.1°C, meeting the harmless treatment requirements of CJJ 52—2014. After 20 days of maturation, the organic fertilizer product had an electrical conductivity below 4.00 mS·cm−1, organic matter content of 51.22%, total nutrient content of 5.61%, and heavy metal concentrations below the limits of NY/T 525—2021. The results provide technical support for efficient treatment and resource utilization of urban and rural organic waste.

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Synergistic Composting of Urban and Rural Multi-Source Organic Waste and Product Quality Evaluation: A Case Study of a Treatment Center in the Taihu Lake Region

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507021• Jan 15, 2026

Health Risk Assessment of Heavy Metals in Soil Around a Landfill Based on Monte Carlo Simulation

Authors: QIN Mengyuan, HE Qiuping, CHEN Dan, MEN Ruixue, JIA Lijuan, MA Linzhuan

The accumulation of heavy metals in soil around municipal solid waste landfills poses potential risks to human health. This study selected a municipal solid waste landfill and monitored the concentrations of eight heavy metals (Zn, Pb, Cd, Ni, Hg, Cu, As, Cr) in surrounding soil. The geo-accumulation index method was used for pollution assessment, and a health risk assessment model recommended by the USEPA, combined with Monte Carlo uncertainty analysis, was employed to evaluate the pollution status and health risks to nearby residents. Results showed that among the eight metals, Pb, Ni, and Cd exceeded risk screening values at 4.26%, 6.38%, and 4.26% of sampling points, respectively. Geo-accumulation indices indicated overall clean conditions (mean < 0), but slight pollution by Pb, Zn, Ni, Hg, and Cd at some points. Probabilistic risk assessment based on Monte Carlo simulation revealed that for both adults and children, the cumulative non-carcinogenic risk was negligible, while carcinogenic risk was acceptable. However, there was a very low probability (approximately 0.2%) of non-carcinogenic risk for children, and probabilities of unacceptable carcinogenic risk were 0.64% for adults and 3.21% for children. Nickel was the primary contributor to carcinogenic risk, and children faced higher health risks than adults. These findings provide a reference for pollution prevention and health risk management of soil around municipal solid waste landfills.

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Health Risk Assessment of Heavy Metals in Soil Around a Landfill Based on Monte Carlo Simulation

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202506021• Jan 15, 2026

Differences in Root Surface Iron Plaque Components between Main and Ratoon Crops of Different Rice Varieties and Their Effects on Cadmium Accumulation in Brown Rice

Authors: ZOU Xinyi, WU Weijian, MA Qiao, ZHANG Qiying, TAN Xiaoyu, ZHENG Feiyu, DAI Rui, YANG Yang, ZENG Qingru, DENG Xiao

To elucidate the seasonal variation in cadmium (Cd) accumulation in ratoon rice and its relationship with root surface iron plaque, this study compared Cd concentrations in brown rice and the characteristics of iron plaque components (amorphous Fe, Am-Fe; crystalline Fe, Cry-Fe) between the main and ratoon crops of six rice varieties under different stubble heights. A field experiment was conducted in a Cd-contaminated paddy in Liuyang, Hunan (soil total Cd: 0.56 ± 0.06 mg·kg⁻¹). Ratoon crop treatments included low stubble (20 cm) and high stubble (60 cm). Brown rice Cd concentrations varied by variety, season, and stubble height. Low stubble generally increased brown rice Cd in the ratoon crop compared to high stubble; high stubble reduced Cd in most varieties relative to the main crop. Health risk assessment indicated that low stubble in the ratoon crop posed higher non-carcinogenic risk than the main crop and high stubble, while carcinogenic risks exceeded acceptable levels across all treatments. Iron plaque Am-Fe and Cry-Fe concentrations in the ratoon crop were generally lower than in the main crop, with Am-Fe consistently exceeding Cry-Fe. In the main crop, total Fe, Am-Fe, and Cry-Fe on root surfaces were significantly negatively correlated with brown rice Cd (P < 0.05), but correlations were not significant in the ratoon crop. High stubble reduced Cd accumulation and non-carcinogenic risk in most varieties, yet carcinogenic risk remained. Iron plaque significantly impeded Cd uptake in the main crop but its effect weakened in the ratoon crop. Selecting low-Cd-accumulating varieties and optimizing stubble height are key strategies for safe ratoon rice production in Cd-contaminated areas.

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Differences in Root Surface Iron Plaque Components between Main and Ratoon Crops of Different Rice Varieties and Their Effects on Cadmium Accumulation in Brown Rice

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202506020• Jan 15, 2026

Multi-objective optimization of high-quality lithium extraction from lepidolite roasting based on neural network coupled modeling

Authors: DUAN Yunlong, LI Huiquan, LIU Changfeng, ZHANG Chenmu, SHI Yao, LIU Shanjun, YAN Chengsheng, FAN Bo, YU Xiuyuan, LI Zhihong, SHI Jingjing, ZHANG Jinlei

The rotary kiln roasting of lepidolite for lithium extraction faces challenges of unstable lithium conversion rates and high energy consumption. To address this, a multi-objective optimization method coupling improved neural network simulation with a multi-objective genetic algorithm was proposed, targeting the synergistic optimization of lithium conversion rate (TRLi) and natural gas consumption intensity (EIng). Using long-term industrial time-series data of batching parameters and kiln operating variables, back-propagation (BP) neural network and its particle swarm optimization (PSO) improved variant were developed to model TRLi and EIng. The PSO-BP model demonstrated superior accuracy in capturing the complex nonlinear relationships, reducing mean absolute percentage errors (MAPE) to 0.278 and 0.284 for TRLi and EIng, respectively. Subsequently, the non-dominated sorting genetic algorithm II (NSGA-II) was employed to construct a multi-objective optimization model, yielding a Pareto-optimal set of process parameters that maximize TRLi and minimize EIng. The results revealed that under NSGA-II optimized conditions, TRLi could be stabilized between 82.45% and 87.96%, an average increase of 3.61 percentage points over baseline operations, while EIng could be reduced to 53.7 m3 per ton of clinker. For an annual processing capacity of 3.2×105 tons of lepidolite concentrate and sulfate mixture, this corresponds to an additional 127.1 tons of lithium metal recovery, a reduction of 1,964,912 m3 in natural gas consumption, and a decrease of 3,763.84 tons in CO2 emissions annually. This study provides theoretical and technical support for the green, high-quality, and low-carbon supply of critical raw materials for the lithium battery new energy industry.

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Multi-objective optimization of high-quality lithium extraction from lepidolite roasting based on neural network coupled modeling

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507038• Jan 15, 2026

Simplified Estimation of Indoor Air Quality Based on Material Pollutant Emission Rates and Concentration Responses

Authors: SUN Mingzhuo, SHEN Chao, BI Xuesong, WANG Fang, DENG Weicai

To enhance the engineering practicality of pollutant pre-assessment, this study conducted environmental chamber tests for formaldehyde and TVOC emissions from 34 common decoration materials (25 solid and 9 liquid categories). Using the IndoorPACT software, variations in indoor pollutant concentrations under different material area loading rates and air change rates were simulated. Taking Harbin as a case study, concentration response ranges for various single materials under different area loading and ventilation conditions were simulated, leading to the construction of a simplified concentration prediction reference table. Results indicate that indoor pollutant concentrations from both solid and liquid materials peak on the second day after decoration, but decay rates differ significantly: liquid materials decrease by 70%–90% within about one week, and given their typically higher area loading rates in real projects, they exert a more significant impact on indoor air quality in the early post-decoration period. In contrast, solid materials decay more slowly and become the dominant long-term pollution source. The simplified estimation method based on these emission characteristics demonstrates good engineering applicability, providing effective reference for material selection, scheme comparison, and preliminary indoor air quality prediction and control in actual decoration projects.

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Simplified Estimation of Indoor Air Quality Based on Material Pollutant Emission Rates and Concentration Responses

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507027• Jan 15, 2026

Field Real-Time Monitoring of Ammonia Nitrogen in Different Water Bodies Using GPMCS

Authors: ZHANG Tongtong, WANG Zhengguo, YAN Haojie, LI Zhaoxing, WANG Zijing, ZHANG Wenjun, LI Tianling

Ammonia nitrogen (NH3-N) is a common water pollutant that can induce eutrophication and threaten aquatic ecosystems and human health. Accurate monitoring is essential for water safety. This study applied a self-developed gas-permeable membrane-based conductivity sensor (GPMCS) for real-time in-situ monitoring of NH3-N in two water bodies. In the Qunying River (surface river water), GPMCS captured concentration fluctuations linked to pump operations and sewage intrusion, with mean inlet and outlet concentrations of 4.67 and 3.42 mg/L, respectively. In Swan Lake (landscape aquaculture water), concentrations reached up to 11.16 mg/L, with site means of 6.42 and 7.04 mg/L, influenced by aquaculture activities, weather, and location. GPMCS results correlated strongly with national standard methods (r1=0.8132, r2=0.7483), confirming accuracy and reliability. Compared to existing techniques, GPMCS offers high selectivity, strong anti-interference, portability, no sample pretreatment, low cost, and environmental friendliness, making it suitable for long-term in-situ monitoring. This technology provides robust support for sustainable water environment management.

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Field Real-Time Monitoring of Ammonia Nitrogen in Different Water Bodies Using GPMCS

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202506053• Jan 15, 2026

Low-Temperature Micro-Oxidation-Driven Synergistic Dealkalization and Soil Reconstruction of Red Mud with Coal

Authors: XIE Erman, ZENG Wei, LI Zhesong, SONG Haoran, TIAN Senlin, HU Xuewei, JU

Red mud, a highly alkaline industrial solid waste from alumina production, poses severe environmental risks due to its high alkalinity, low organic matter content, and poor aggregation, which critically impede its soil reconstruction and ecological utilization. This study proposes a novel approach of low-temperature micro-oxidation to drive the synergistic soil reconstruction of red mud and coal. By constructing a low-temperature micro-oxidation atmosphere, the soil properties of the reaction products were investigated, the decomposition and reconstruction of alkaline minerals and alkali release were analyzed, and the oxidation of carbon-based minerals and organic matter transformation in coal were examined. The mechanism of the synergistic reaction between red mud and coal under low-temperature micro-oxidation was elucidated. Results showed that at 250 °C under micro-oxidation, the pH of the product decreased to 8.47, organic matter content increased to 12.98%, and the proportion of aggregates >0.250 mm increased. Alkaline minerals such as cancrinite and grossular in red mud underwent decomposition and reconstruction in the low-temperature hydrothermal environment, releasing substantial free alkali. The condensed aromatic rings of carbon-based minerals in coal were oxidized by free radicals, leading to ring-opening and bond cleavage, producing small-molecule organic acids and macromolecular humic acids. The continuous oxidation of carbon-based minerals in coal generated acids, which neutralized the alkali released from red mud, driving sustained dealkalization. The inorganic particles of red mud flocculated with macromolecular humic acids, forming micro-aggregates and significantly improving soil properties. This research provides technical support for the rapid ecological utilization of red mud at industrial scale.

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Low-Temperature Micro-Oxidation-Driven Synergistic Dealkalization and Soil Reconstruction of Red Mud with Coal

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507030• Jan 15, 2026

Spectrophotometric Method for Rapid Determination of As(V) and As(III) in Industrial Wastewater

Authors: ZHOU Guotao, KONG Linghao, ZHAO Yanxia, WANG Enquan, PENG Xianjia

Arsenic is a toxic metalloid predominantly present in water as As(V) and As(III), whose speciation governs toxicity and mobility. Conventional speciation methods (HPLC-ICP-MS, IC-HG-AFS) offer ultralow detection limits but suffer from high cost, long analysis times, and non-portability, hindering on-site rapid monitoring. This study presents a sulfide-based spectrophotometric method exploiting the quantitative reaction between As(V) and S2− to form monothioarsenate (H3AsO3S) with a characteristic absorption at 233 nm. Under optimized conditions (H+ concentration 1 mol·L−1, Na2S dosage 5 mmol·L−1, reaction time 3 min, N2 purging 2 min), As(V) is directly quantified. Total arsenic is determined after complete oxidation of As(III) to As(V) using NaClO (10 mmol·L−1, pH 12, 5 min), and As(III) is obtained by difference. The method exhibits linearity over 0.5–50 mg·L−1 (A = 0.0209c + 0.0627, R² = 0.999), a detection limit of 0.17 mg·L−1, spike recoveries of 101.9%–104.1%, and relative standard deviation of 1.06%. Validation against real industrial wastewater samples showed relative deviations <10% compared with HPLC-ICP-MS and IC-HG-AFS. Total analysis time is within 15 min. The method is simple, cost-effective, and suitable for field monitoring.

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Spectrophotometric Method for Rapid Determination of As(V) and As(III) in Industrial Wastewater

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507032• Jan 15, 2026

Emission Reduction Effects and Costs of Energy Policies under Carbon Neutrality Pathways in Guangdong Province

Authors: LIU Jiangtao, LIU Zhen, LIAO Cuiping, HUANG Ying

To mitigate global warming, regional carbon neutrality pathways are critical. Based on the Guangdong Energy Policy Simulator (EPS) model, this study simulates total energy consumption and greenhouse gas (GHG) emissions under baseline, Carbon Neutral 60 (CN60), and Carbon Neutral 50 (CN50) scenarios, and analyzes the emission reduction effects and costs of various energy policies. Results show that by 2060, total energy consumption under CN60 and CN50 decreases by 39% and 44% relative to baseline, respectively. Primary electricity and other energy, natural gas, oil, and coal account for 56%, 26%, 14%, and 4% under CN60, and 60%, 24%, 13%, and 3% under CN50. GHG emissions under CN60 drop to 80×10^6 tCO2e by 2060, an 89% reduction from 2020; under CN50, emissions reach 92 and 55×10^6 tCO2e in 2050 and 2060, respectively, reductions of 87% and 92% from 2020. Policies such as increasing clean electricity share, industrial electrification (hydrogen), increasing green power purchases, building electrification, F-gas reduction, and improving industrial energy efficiency standards show significant reduction effects, with clean electricity share being the primary source. Policies like improving industrial energy efficiency standards, increasing industrial product utilization, and increasing clean energy vehicle market penetration are cost-effective; increasing clean electricity share, green power purchases, building electrification, and F-gas reduction effectively balance reduction effects and costs. Industrial electrification (hydrogen) contributes >5% cumulative reduction but faces economic challenges for full-scale promotion in the short term; industrial carbon capture and storage and electrolytic hydrogen contribute <2% cumulative reduction with high costs. Therefore, Guangdong should prioritize cost-effective policies, promote balanced policies, gradually optimize energy structure, achieve clean electricity, and foster green industrial transformation to achieve carbon neutrality at lower economic cost.

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Emission Reduction Effects and Costs of Energy Policies under Carbon Neutrality Pathways in Guangdong Province

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507043• Jan 15, 2026

Thermal Steel Ball-Enhanced Rotary Drum Drying of Sludge: Drying Characteristics, Moisture Diffusion Behavior, and Mechanisms

Authors: YU Shilin, ZHU Jinwei, LU Zhengnan, DENG Shuanghui, ZHOU Ao, WANG Xuebin, TAN Houzhang, PAN Zhicheng

Municipal sludge with high moisture content and strong viscosity tends to form a dense crust during conventional rotary drum drying, reducing heat and mass transfer efficiency and prolonging drying time. This study proposes a thermal steel ball-enhanced rotary drum drying method that introduces high heat capacity, high thermal conductivity steel balls to achieve synergistic contact heat conduction and mechanical disturbance. An evaluation system incorporating dimensionless moisture ratio (MR), drying rate (DR), characteristic drying time (tdry), effective moisture diffusivity (Deff), and volumetric evaporation intensity (U) was established. Results show that compared with conventional drying, steel ball-enhanced drying increased maximum drying rate (DRmax) by 22.59%–41.19%, U by 38.06%–93.43%, and shortened tdry by 27.56%–48.30%, with more pronounced advantages under high load conditions. Deff was significantly higher throughout the process, with maximum increase up to 48.30%, indicating that ball rolling and collision effectively disrupt the crust and promote moisture migration. Mechanistic analysis reveals that the performance enhancement arises from the dual action of thermal-mechanical coupling and mechanical disturbance, which enhances local heat flux via contact conduction and dynamically renews the drying interface, shortening diffusion paths. This study elucidates the heat and mass transfer mechanisms of thermal steel ball-enhanced sludge drying, providing theoretical support and technical reference for efficient sludge volume reduction and dryer design optimization.

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Thermal Steel Ball-Enhanced Rotary Drum Drying of Sludge: Drying Characteristics, Moisture Diffusion Behavior, and Mechanisms

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507029• Jan 15, 2026

Environmental Risk Assessment of Aerated Concrete Prepared by Synergistic Utilization of Incineration Fly Ash and Multi-Source Solid Wastes

Authors: SHI Songwei, ZHANG Wenpei, ZHAO Cheng, SUN Yansong, ZHANG Yan, YAN Mi

This study systematically evaluates the environmental risks associated with the resource utilization of municipal solid waste incineration (MSWI) fly ash in the production of aerated concrete, co-prepared with multiple solid wastes. The focus is on the leaching behavior and total content of heavy metals (Cr, Pb, Cd, Cu, Zn) under CO2 curing and chelating agent stabilization. Water washing pretreatment parameters (liquid-to-solid ratio, washing time, ash-to-slag ratio) were optimized for chloride removal. Results demonstrate that CO2 curing suppresses the leaching of most metals; leaching concentrations of Cr, Pb, Cd, and Zn decrease with reduced fly ash content, whereas Cu leaching increases when fly ash is absent. The addition of 17.5% organic sulfur stabilizer (DTC) significantly outperforms inorganic sulfide (Na2S) in immobilizing heavy metals, achieving compliance with national standards without compromising compressive strength or carbon sequestration. Water washing effectively reduces soluble chloride content to below 1% (mass fraction), meeting the HJ 1134-2020 regulatory limit. Optimal parameters include a liquid-to-solid ratio of 5, washing time of 20 min, and a raw material ratio of incineration bottom slag:fly ash:slag = 40:20:40. Under these conditions, the final product exhibits a compressive strength of 1.50 MPa, with heavy metals and soluble chlorides fully compliant. This work provides key technical support for the safe recycling of MSWI fly ash in building materials.

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Environmental Risk Assessment of Aerated Concrete Prepared by Synergistic Utilization of Incineration Fly Ash and Multi-Source Solid Wastes

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507051• Jan 15, 2026

Dynamic Ammonia Emission Patterns and Recovery from Growing-Finishing Pig Houses

Authors: SONG Yanan, WAN Junfeng, GUO Xiaoying, ZHANG Jie, WANG Yan

This study investigated the dynamic characteristics and recovery of ammonia emissions from a growing-finishing pig house in Yanshi District, Luoyang City, Henan Province, China. High-sensitivity electrochemical sensors and an ammonia absorption recovery device were employed for continuous monitoring and treatment of exhaust air. The results revealed periodic fluctuations in ammonia emission concentrations, strongly correlated with indoor temperature and humidity. Over the entire monitoring period, the average daily ammonia concentration in exhaust air was 9.852 mg·m−3, below the national emission limit of 25 mg·m−3. However, during high-temperature periods (>30 °C), localized concentrations reached 38.36 mg·m−3. Humidity, particularly from spray cooling, temporarily suppressed ammonia volatilization, but its effect was modulated by temperature. Total ammonia emitted during the study was 1380.4 kg, with an average per-pig emission rate of 0.034 kg·d−1. After treatment with the exhaust gas absorption device, the average daily ammonia concentration dropped to 0.437 mg·m−3, achieving a mean recovery efficiency of 93.5%. These findings demonstrate that controlling environmental factors and employing external air absorption devices can significantly reduce ammonia emissions, offering a viable pathway for mitigating nitrogen pollution from livestock operations and promoting resource recovery.

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Dynamic Ammonia Emission Patterns and Recovery from Growing-Finishing Pig Houses

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202506031• Jan 15, 2026

Preparation and Engineering Scale-Up of Cyanobacteria-Based Columnar Activated Carbon

Authors: WU Jing, HUANG Dongxu, WU Nan, PU Tian, ZHU Ge, ZHENG Jinxing, ZHENG Zhiyong, LIU He

The production of activated carbon from waste biomass such as cyanobacteria from Lake Taihu represents a promising resource utilization route. However, existing studies are mostly confined to laboratory scale, and the gap between laboratory processes and industrial production hinders the evaluation of technical feasibility and economic viability. This study optimized the process for producing cyanobacteria-based columnar activated carbon by co-processing cyanobacteria with garden waste (sawdust), and validated the process on an engineering-scale production line with a daily capacity of 5 t of raw materials. Economic feasibility was also assessed. Results showed that the optimized activated carbon exhibited a particle strength of 91.3% and a specific surface area of 571.44 m2·g−1. The engineering-scale line processed 5 t of raw materials daily, yielding approximately 1.18 t of activated carbon with stable quality: strength of 94.3% and specific surface area of 471.42 m2·g−1, featuring a microporous-dominant structure with coexisting micropores and mesopores. Cost analysis indicated a production cost of 3,595.65 CNY per ton of activated carbon, demonstrating favorable economic benefits. This work provides a basis for larger-scale production and application of cyanobacteria-based activated carbon.

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Preparation and Engineering Scale-Up of Cyanobacteria-Based Columnar Activated Carbon

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507046• Jan 15, 2026

Carbon Footprint Accounting Method for Electromechanical Products Based on Life Cycle Assessment

Authors: WEI Xikai, RUAN Jiatong, TAN Xiaoshi

Addressing the insufficient applicability and accuracy of carbon footprint accounting for electromechanical products due to data gaps, this study proposes an accounting method based on life cycle assessment (LCA). Using LCA as the overall framework with a system boundary of "cradle to gate", the method constructs a carbon footprint accounting approach combining substitution algorithms and correction coefficients for different data missing scenarios from suppliers, manufacturers, and databases. Data quality indicators and Monte Carlo simulation are employed to quantify data quality and uncertainty, while single-factor and multi-factor sensitivity analyses identify key influencing factors. Taking an optical gyrocompass as a case study, the carbon footprints and uncertainties under eight typical data missing scenarios are explored, and robustness checks are conducted on five typical products including transformers, high-speed diesel engines, and wind turbines. As data missing degree deepens, the carbon footprint deviation of the optical gyrocompass increases from 0.05% to 3.03%, and uncertainty rises from 2.65% to 5.45%. Under mixed data missing scenarios, the carbon footprint uncertainties of all five electromechanical products remain below 10%. The method exhibits wide applicability, strong implementability, and high accuracy, effectively supporting carbon footprint accounting for electromechanical products, reducing carbon tariff risks, optimizing emission reduction strategies, and promoting green development.

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Carbon Footprint Accounting Method for Electromechanical Products Based on Life Cycle Assessment

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507055• Jan 15, 2026

Rapid Identification of Industrial Wastewater Discharges in Municipal Sewer Networks Based on Three-Dimensional Fluorescence Spectroscopy and Spectral Angle Mapping

Authors: JI Yuxi, HU Wei, ZHU Huifeng, ZHAO Zhonghua, ZHANG Guanyi, YU Xubiao

The increasing complexity of pollutant sources in municipal wastewater networks, driven by unauthorized industrial discharges, poses significant risks to the stable operation of wastewater treatment plants. This study, conducted in an industrial park in Ningbo, Zhejiang Province, developed a source apportionment method using excitation-emission matrix (EEM) fluorescence spectroscopy combined with spectral angle mapping (SAM). A pollution fingerprint database was constructed from wastewater samples of six representative enterprises (A–F) and municipal sewer samples. The SAM algorithm demonstrated high sensitivity and stability in detecting changes in water composition, with spectral angle values showing a strong linear correlation (R² > 0.88) with the volume ratio of enterprise wastewater in mixed samples. This enabled both qualitative identification and quantitative estimation of pollution sources. Field application over a 12-hour monitoring period identified two enterprises as major contributors to organic matter and nitrogen during critical pollution episodes, consistent with trends in DOC, TN, and UV254. The proposed EEM+SAM approach offers a non-invasive, high-throughput method for real-time monitoring and source tracing of multi-source pollution in complex sewer systems, providing a scientific basis for pollution accountability and precise enforcement.

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Rapid Identification of Industrial Wastewater Discharges in Municipal Sewer Networks Based on Three-Dimensional Fluorescence Spectroscopy and Spectral Angle Mapping

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202512072• Jan 15, 2026

Intelligent Detection of Drainage Pipeline Defects Based on Cross-Frame Annotation and Recall Optimization

Authors: XU Xingquan, CHEN Ben, ZHU Zeyu, LIU Shaohui, SUN Yiye, CHEN Hangbiao, CHEN Zhanli, LYU Hui

Drainage pipeline defect detection predominantly relies on closed-circuit television (CCTV) inspection, which is labor-intensive, inefficient, and prone to missed detections. Although deep learning-based object detection has been applied, it suffers from low precision, recall, and speed in practical scenarios. This study proposes an engineering-oriented detection scheme achieving high recall and low miss rates. The annotation phase employs a cross-frame strategy combining manual labeling of first and last frames with interpolation and tracking-based refinement. Data preprocessing introduces perceptual hashing to identify similar images, enhancing training efficiency. For detection, a Faster R-CNN model is enhanced with Focal Loss to focus on hard examples, defect classification and grading, and a dynamic threshold strategy to improve recall. Validated on 5,068.72 m of real pipeline data, the method achieves a recall rate exceeding 98% across 16 defect categories, a miss rate of only 2% for grade 4 defects, and a 425% improvement in per-segment detection efficiency compared to manual screening. These results demonstrate the method's effectiveness in balancing recall, miss rate, and speed for engineering deployment.

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Intelligent Detection of Drainage Pipeline Defects Based on Cross-Frame Annotation and Recall Optimization

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Original ResearchVol. 20, Issue 3 • pp. 100-112DOI: 10.12030/j.cjee.202507057• Jan 15, 2026

Rapid Detection of Trace Pb(II) in Water Using a Rod-Shaped Bismuth-Based Electrode

Authors: WANG Chencan, YANG Yuxi, WAN Junfeng, GUO Xiaoying, XU Zicong, YANG Jinghe, ZHANG Jie, JU

This study presents a novel electrochemical sensor for the rapid detection of trace lead ions (Pb(II)) in water, utilizing a rod-shaped bismuth-based electrode. The electrode was fabricated by modifying a glassy carbon electrode (GCE) with basic bismuth nitrate [Bi6O5(OH)3](NO3)5·3H2O, synthesized via a chemical precipitation method. The sensor was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), electron probe microanalysis (EPMA), and energy-dispersive X-ray spectroscopy (EDS), confirming the rod-like morphology and composition. Electrochemical detection was performed using differential pulse voltammetry (DPV) in a 0.1 mol·L−1 NaAc-HAc buffer (pH 4.3). The sensor exhibited a linear detection range for Pb(II) from 1 to 90 μg·L−1, with a detection limit of 0.34 μg·L−1 and a sensitivity of 106 μA·(μmol·L−1)−1. The electrode demonstrated excellent anti-interference capability and reproducibility. Recovery tests in real water samples (tap water and campus lake water) yielded high recovery rates, indicating practical applicability. This work provides a simple, cost-effective, and reliable method for monitoring trace Pb(II) in environmental water, particularly relevant for public swimming pools and similar aquatic facilities.

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Rapid Detection of Trace Pb(II) in Water Using a Rod-Shaped Bismuth-Based Electrode

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202508092• Jan 15, 2026

Identification and Evolution Analysis of Research Hotspots on Per- and Polyfluoroalkyl Substances in Soil

Authors: SHENG Ding, CAI Kejie, LIU Yao, CAO Yaowu, WU Xiang

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants with high environmental stability and bioaccumulation potential, posing risks to soil ecosystems and human health. To systematically map research hotspots and evolutionary trends, a bibliometric analysis was conducted on 1,459 publications from the Web of Science Core Collection and CNKI (1985–2025) using VOSviewer and Python. Keyword clustering identified four primary research themes: (1) transport and transformation of PFAS in soil, (2) bioaccumulation and toxic effects, (3) environmental fate and risk assessment of novel PFAS, and (4) remediation strategies for legacy PFAS. Temporal trend analysis using a trend factor (T) revealed a shift from early toxicological studies to policy-driven growth post-2006, with recent emphasis on remediation technologies, migration mechanisms, and bioconcentration. Future research priorities include understanding the fate of novel substitutes in complex media, developing green and sustainable remediation technologies, and establishing robust validation frameworks. The study provides a comprehensive knowledge map to guide scientific prevention and efficient governance of PFAS contamination.

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Identification and Evolution Analysis of Research Hotspots on Per- and Polyfluoroalkyl Substances in Soil

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202507013• Jan 15, 2026

Hydrochemical Characteristics and Health Risk Assessment of Karst Underground River Water in Southwest China: A Case Study of the Pingjiang Underground River Basin, Guangxi

Authors: 覃佳肖, 郑焕君, 李金明, 冯俊海, 侯萍萍, 张勤军, 黄春阳, 贝为昶

Karst groundwater systems in Southwest China are vital for water supply and ecosystem health in traditional agricultural regions. This study investigated the hydrochemical characteristics and health risks of groundwater in the Pingjiang Underground River Basin, a typical karst agricultural area. Forty-two groundwater samples were collected during wet, normal, and dry seasons. Hydrochemical facies were analyzed using comprehensive hydrochemical methods, and water quality was assessed using the objective combined weight water quality index (OCWQI) and a health risk model. Results showed that groundwater was weakly alkaline and slightly hard, with HCO3− and Ca2+ as dominant ions. The chemical composition followed a seasonal order: dry > normal > wet season. All samples were of HCO3-Ca type. Hydrochemistry was primarily controlled by silicate and carbonate weathering, with significant anthropogenic influence indicated by elevated NO3− concentrations from agricultural activities. Health risk assessment revealed that in normal and dry seasons, 64% and 79% of samples for adults, and 64% and 86% for children, exceeded the natural NO3− threshold of 3 mg·L−1, corresponding to low non-carcinogenic risk levels (adults: 0.09<RHI<0.30; children: 0.06<RHI<0.20). Spatial distribution of risk increased from northwest to southeast, with children at higher risk than adults. These findings provide a scientific basis for groundwater management and protection in karst agricultural basins.

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Hydrochemical Characteristics and Health Risk Assessment of Karst Underground River Water in Southwest China: A Case Study of the Pingjiang Underground River Basin, Guangxi

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202505012• Jan 15, 2026

Risk Assessment of Heavy Metal Pollution Characteristics in Environmental Dredging Sediment from Dianchi Lake under Multi-Scenario Land Use

Authors: DUAN Huibo, XING Hao

Sediment risk assessment for lakes and rivers often neglects the distinction between in-situ ecological risks and ex-situ comprehensive utilization risks. This study proposes a multi-scenario risk assessment model incorporating both in-situ and ex-situ contexts. For the in-situ scenario, a dual-background-value potential ecological risk assessment was applied using national and Yunnan soil background values. For ex-situ scenarios, pollution risk assessment models were established for agricultural land (paddy and other) and construction land (Class I and II). Taking the Dianchi Lake dredging project as a case study, 92 sediment samples from polluted and transition layers at 46 grid points were analyzed for six heavy metals (As, Hg, Cd, Zn, Cu, Cr). Results showed: (1) Under different background values, ≥97.83% of samples exhibited moderate or higher ecological risk, with Hg and Cd as main contributors, Hg posing higher risk. (2) In agricultural scenarios (paddy/orchard and other), 95.65% of points had unacceptable risk, with comprehensive pollution intensity order Cd>Cu>Zn>As>Cr; for Class I construction land, As was the target pollutant with 93.48% of points unacceptable, while Class II land was acceptable. (3) Spatial heterogeneity was significant: horizontal risk was higher at the lake outlet than at the Cixiang River inlet; vertical risk was higher in the polluted layer than in the transition layer, with Hg and Cd potential ecological risk coefficients 11.58% and 24.19% higher, and comprehensive potential ecological risk index 43.27% higher. Pollution coefficients for Cd, Zn, Cu (agricultural) and As (Class I construction) increased by 123.02%, 6.3%, 4.1%, and 41.02% in the polluted layer. (4) Different evaluation methods yielded significantly different results, indicating that metals without potential ecological risk may still pose pollution risk in utilization scenarios, necessitating comprehensive consideration in remediation.

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Risk Assessment of Heavy Metal Pollution Characteristics in Environmental Dredging Sediment from Dianchi Lake under Multi-Scenario Land Use

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202507058• Jan 15, 2026

Research Progress on Recycling Technologies for Cathode Materials of Spent Lithium Iron Phosphate Batteries

Authors: CHEN Weiju, YU Xinyi, JIANG Yang

With the rapid development of China's lithium-ion power battery industry, the recycling of large-scale retired batteries has become a critical link for the sustainable development of the new energy vehicle industry. The recovery of cathode materials from spent lithium iron phosphate (LiFePO4) batteries is a current research hotspot, significant for resource recycling and environmental protection. This study systematically reviews recent progress in recycling technologies for spent LiFePO4 cathode materials, mainly including direct regeneration, pyrometallurgy, and hydrometallurgy. It focuses on analyzing the current research status of key steps in hydrometallurgy, such as leaching of valuable elements, deep removal of impurities, and product regeneration, and compares the advantages and limitations of various methods. Addressing core issues in current recovery processes, such as insufficient high-value utilization of iron and phosphorus resources and difficulty in deep impurity removal, this study proposes corresponding solutions and technical prospects, aiming to provide theoretical reference and engineering guidance for efficient, clean, and high-value recycling of spent LiFePO4 batteries.

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Research Progress on Recycling Technologies for Cathode Materials of Spent Lithium Iron Phosphate Batteries

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202507088• Jan 15, 2026

Rapid Granulation of Anaerobic Sludge in Methanol Wastewater Treatment Using Functional Additives

Authors: XIAO Yan, SONG Liuying, LIU Yang, CUI Bing, WU Bin, LI Yuyou

Methanol is highly biodegradable, yet its efficient and stable anaerobic treatment is constrained by prolonged microbial adaptation to toxic substances, narrow microbial community structure, and poor sludge granulation. This study applied two functional additives—sodium bicarbonate (NaHCO3) as an inorganic carbon source (IC) and an amino-acid-rich organic functional supplement (FS)—to accelerate the startup of two upflow anaerobic sludge blanket (UASB) reactors. UASB-A received 3,000 mg·L−1 NaHCO3 and 127 mg·L−1 FS, while UASB-B received only 3,000 mg·L−1 NaHCO3. Both additives enabled rapid startup and granulation by shortening hydraulic retention time (HRT) and increasing organic loading rates (4, 6, 9, 15, 20, and 30 g COD·L−1·d−1). Granulation was evidenced by increased total suspended solids (TSS), volatile suspended solids (VSS), and particle size distribution. Microbial community analysis at HRT 0.2 d revealed highest relative abundances of Acetobacterium at 30.2% (UASB-A) and 36.9% (UASB-B). NaHCO3 supplementation enhanced syntrophy between Acetobacterium and the acetoclastic methanogen Methanothrix, while FS significantly increased the abundance of Sporomusa, establishing a novel syntrophic relationship with Methanothrix. These interactions promoted sludge granulation. The study demonstrates that functional additives facilitate rapid startup and granulation in methanol anaerobic treatment, offering a strategy to overcome process bottlenecks.

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Rapid Granulation of Anaerobic Sludge in Methanol Wastewater Treatment Using Functional Additives

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202508013• Jan 15, 2026

Water Quality Trend Analysis of the Sanshenggong Section of the Yellow River from 2011 to 2024 Based on Mann-Kendall Test and Fuzzy Comprehensive Evaluation

Authors: YU Yongkun, ZHANG Lieyu, DU Caili, GAO Shengwang, BAI Yangwei, WEI Yimei, TIAN Zhenjun, JU

The Sanshenggong section of the Yellow River is a critical hydrological monitoring and control point, whose water quality directly affects the ecological safety and sustainable water resource utilization of the middle and lower reaches. This study analyzed water quality monitoring data from 2011 to 2024 using the Mann-Kendall test to identify abrupt change years, combined with single-factor evaluation and a fuzzy comprehensive evaluation method improved by CRITIC-entropy weight combination to systematically assess water quality evolution. The Mann-Kendall test identified 2013 and 2019 as abrupt change points, with non-significant improvement from 2013 to 2015 and significant improvement after 2016. Single-factor evaluation indicated that total phosphorus (TP) was the primary exceeding factor in 2011–2012, and its declining concentration drove the water quality upgrade from Class III to Class II in 2013. The CRITIC-entropy weight combination assigned the highest weight (28.96%) to permanganate index, whose decline was the core driver of water quality improvement. The improved fuzzy evaluation showed that the membership degree of Class III water dropped to zero in 2013, indicating stable improvement, but periodic rebounds in Class II membership suggested potential degradation risks. This study provides scientific evidence for ecological protection and high-quality development of the Yellow River Basin.

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Water Quality Trend Analysis of the Sanshenggong Section of the Yellow River from 2011 to 2024 Based on Mann-Kendall Test and Fuzzy Comprehensive Evaluation

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202507081• Jan 15, 2026

Analysis of Treatment and Resource Utilization of Coal Chemical Waste Salt: Current Status and Prospects

Authors: YANG Jun, HE Yi, XU Jie, LIU Yanping, LIU Guoliang, LIU Haibing

Coal chemical waste salt, a solid residue from evaporative crystallization of high-salinity wastewater, poses significant environmental risks and challenges for resource utilization due to its complex composition. This study systematically analyzes its composition and environmental hazards, highlighting its typical "mixed salt" nature and the potential threats of organic pollutants and heavy metals to soil, water, and ecosystems. It reviews mainstream treatment pathways, including organic degradation, inorganic impurity removal, and salt separation, with a focus on the resource utilization of sodium chloride and sodium sulfate and their industrial prospects. The current pollution control technical specifications and product quality standards are examined, comparing the scope and technical points of relevant standards such as the "Technical Specification for Pollution Control of Chemical Waste Salt." Finally, countermeasures are proposed to address challenges including difficult treatment of mixed salts, insufficient resource utilization incentives, and incomplete standard systems, emphasizing technological innovation, policy guidance, and standard improvement.

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Analysis of Treatment and Resource Utilization of Coal Chemical Waste Salt: Current Status and Prospects

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202510089• Jan 15, 2026

Removal Mechanisms of Fe3O4@MIL-100(Fe) for Microplastics in Water

Authors: TENG Xueyan, YANG Yuesuo, YANG Zhaofei, YANG Wenyue, SONG Xiaoming

Microplastics (MPs) are frequently detected in various water bodies, posing increasing environmental risks. This study synthesized magnetic Fe3O4@MIL-100(Fe) microspheres via an in-situ one-step hydrothermal method and investigated their adsorption removal mechanisms for polystyrene (PS) and polylactic acid (PLA) microplastics. The composite exhibited a core-shell structure with a high specific surface area of 848.6 m2·g−1. Adsorption kinetics showed that PLA followed a pseudo-second-order model, while PS fitted both pseudo-first-order and pseudo-second-order models. Equilibrium data for both MPs were well described by the Freundlich isotherm. Removal efficiencies for PLA and PS increased from 58.18% and 49.66% to 98.90% and 98.58%, respectively, as pH decreased, and from 64.24% and 21.58% to 97.05% and 94.63% with increasing ionic strength. The removal mechanism involved synergistic physical-chemical interactions: hydrogen bonding dominated for PLA, with some complexation, while π–π interactions and hydrogen bonding were primary for PS. The material demonstrated excellent reusability over multiple cycles. These findings highlight the potential of Fe3O4@MIL-100(Fe) for efficient removal of MPs from water, offering a novel approach for controlling emerging contaminants.

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Removal Mechanisms of Fe3O4@MIL-100(Fe) for Microplastics in Water

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202509035• Jan 15, 2026

A Novel Continuous-Flow Self-Circulating Upflow Granular Sludge Bed Process for Treating Real Domestic Wastewater

Authors: HU Rui, SUN Yuge, ZHANG Jingyu, QI Weikang, JU (Corresponding author: QI Weikang)

Aerobic granular sludge (AGS) is an economical and efficient technology, yet its application has been largely confined to sequencing batch reactors (SBRs). This study introduces a novel continuous-flow self-circulating upflow granular sludge bed (Zier) process with separate aeration for treating real domestic wastewater. By regulating operational parameters, the nitrogen removal performance and granular sludge stability were investigated. Under hydraulic retention time of 10 h, self-circulation times of 29–58, and upflow velocity of 11–18 m·h−1, effluent NH4+-N and TN averaged (5±3.4) mg·L−1 and (10±2.8) mg·L−1, respectively, with COD at (30±6.2) mg·L−1. The process maintained sludge stability: mixed liquor suspended solids increased from 5,080 to 6,650 mg·L−1, mean particle size was 209.6 μm, and sludge volume index (SVI) remained at 50–60 mL·g−1. Extracellular polymeric substances (EPS) increased from 26.05 to 68.27 mg·g−1, with proteins (PN) rising from 21.26 to 59.44 mg·g−1 and polysaccharides (PS) from 4.79 to 8.82 mg·g−1, elevating the PN/PS ratio from 4.4 to 6.7. These results confirm that the Zier process preserves granular structure and function in continuous flow. The process demonstrates robust nitrogen removal and offers a novel approach for continuous-flow AGS applications in real wastewater treatment.

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A Novel Continuous-Flow Self-Circulating Upflow Granular Sludge Bed Process for Treating Real Domestic Wastewater

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202508036• Jan 15, 2026

Optimization of Preparation Conditions for a Novel Composite Slow-Release Carbon Source and Its Denitrification Performance

Authors: CHEN Xiaonan, GU Jiayan, HE Guofu, JU, GUO Linrui, ZHANG Ruirui

To address the issues of insufficient carbon sources and low denitrification efficiency in rural domestic wastewater, this study developed and optimized a composite slow-release carbon source using corncob, rice husk, reed straw, polyvinyl alcohol (PVA), and sodium alginate (SA). The preparation conditions and raw material ratios were systematically optimized using Plackett-Burman (PB) design, response surface methodology (Box-Behnken design, BBD), and mixture-optimal design (MOD). The denitrification performance was evaluated through carbon release characteristics and denitrification experiments. The optimal preparation conditions were determined as PVA 8.64 g, SA 2.41 g, rice husk 3.82 g, corncob 4.47 g, reed straw 6.06 g, freezing time 19.11 h, and crosslinking time 12 h. The 7-day cumulative carbon release was (43.38 ± 1.3) mg·(g·h)−1. The release process followed first-order kinetics, Higuchi, Ritger-Peppas, and Weibull models, indicating that carbon release is controlled by multiple mechanisms including diffusion and skeleton erosion, ensuring stable slow-release characteristics. In denitrification experiments with influent NO3−-N concentration of 50 mg·L−1, the composite carbon source (RCR-PVA-SA) achieved a maximum NO3−-N removal rate of 90.8% after 10 days of operation, with a removal rate of 0.079 mg·(g·h)−1. Under dynamic conditions with hydraulic retention time (HRT) of 3 h, the average removal rate remained at 87.9%, demonstrating efficient and stable denitrification performance under both static and dynamic conditions. This research provides a reference for the preparation of natural slow-release carbon sources and the resource utilization of agricultural waste.

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Optimization of Preparation Conditions for a Novel Composite Slow-Release Carbon Source and Its Denitrification Performance

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202410085• Jan 15, 2026

Removal of Pollutants from Urban Surface Runoff by a Straw-Based Composite Bioretention System

Authors: HE Lin, ZHU Zheng, MA Shun, HE Hua, LIANG Wenyan, JU ...

Surface runoff pollution has become a significant source of water contamination. This study constructed an integrated composite bioretention system comprising straw, aquatic plant, and biochar zones for purifying urban surface runoff, aiming to meet the standards for reuse as landscaping water. The system's performance in removing conventional pollutants and polycyclic aromatic hydrocarbons (PAHs) was investigated, along with microbial community structure analysis. Results showed removal efficiencies of 81.1% for COD, 98.1% for TN, 79.1% for TP, and 90.3% for TSS, with effluent meeting the 'Water Quality for Scenic and Recreational Use' (GB/T 18921-2019) standard. The system exhibited robust resistance to pollutant and hydraulic loading. The alkali-modified straw zone was the primary pollutant removal region, facilitating physical adsorption and capture of suspended solids, while released carbon sources enhanced total nitrogen removal. This zone exhibited the highest microbial richness, with relative abundances of Proteobacteria and Firmicutes at 54.3% and 21.9%, respectively. The system effectively removed all 16 priority PAHs, reducing effluent toxicity equivalent by 86.5%. The straw zone completely removed four high-molecular-weight PAHs (BaP, DahA, BghiP, IcdP), while aquatic plants and biochar effectively removed medium- and low-molecular-weight PAHs.

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Removal of Pollutants from Urban Surface Runoff by a Straw-Based Composite Bioretention System

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202506084• Jan 15, 2026

Multidimensional Groundwater Quality Assessment and Source Apportionment in the Guyuan Region, Ningxia

Authors: LIU Yuxi, HUANG Yong, LIU Hong, SU Yue, LIU Hui, MA Yuxue, ZHANG Jinghua, YUAN Jianfei, YI Chengtai

Groundwater is a vital drinking and irrigation source in the loess regions of northwestern China. In Guyuan, a densely populated area in southern Ningxia, systematic assessments of groundwater pollution risks are lacking. This study collected 60 groundwater samples and employed the Nemerow index, heavy metal pollution index (HPI), and health risk assessment models to evaluate pollution levels and health risks of eight elements including Cr, As, and Hg. Results show that the groundwater is generally Class IV quality, with a mean TDS of 1350.9 mg·L−1. Average concentrations of As, Cr, and Mn are 4.39, 29.87, and 45.77 μg·L−1, respectively. The Nemerow index indicates moderate pollution. The mean HPI is 10.56, but a local sample (PS1-51-下) reaches 36.15, indicating severe pollution. Health risk assessment reveals that carcinogenic risks from Cr and As for adults and children are 8.037×10−6 a−1 and 3.863×10−6 a−1, respectively, below US EPA limits but above recommended levels by Swedish and Dutch agencies, with children at higher risk. Hydrogen and oxygen isotopes and principal component analysis suggest that groundwater is primarily recharged by atmospheric precipitation. Cr, Zn, and Mn mainly originate from regional copper ore belts, coal mining, and agricultural activities. This study fills a gap in multidimensional groundwater assessment in populated loess areas, identifies pollution characteristics distinct from typical loess regions, and provides a scientific basis for regional water resource risk management and sustainable development.

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Multidimensional Groundwater Quality Assessment and Source Apportionment in the Guyuan Region, Ningxia

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202508053• Jan 15, 2026

Biosurfactant-Enhanced Electrokinetic-Biobarrier Remediation of Polycyclic Aromatic Hydrocarbon-Contaminated Soil from an Industrial Site

Authors: HAN Yana, LI Jingming, LI Bingni, TONG Menghan, XI Kailu, LI Fengmei

Polycyclic aromatic hydrocarbons (PAHs) in industrial soils pose significant risks due to their hydrophobicity and low bioavailability, limiting the efficacy of bioremediation. This study investigated the enhancement of an in-situ electrokinetic-biological barrier (EK-BB) system for PAH-contaminated soil using biosurfactants. Three biosurfactants—rhamnolipid (RL), alkyl polyglycoside (APG), and saponin (SAP)—were applied individually and in combinations at 10× critical micelle concentration (CMC), and the optimal RL+APG mixture was further tested at 2.5, 5.0, 7.5, and 10× CMC. Results showed that biosurfactant application improved soil electrical current, moisture retention, and PAH removal. Combined surfactants outperformed single ones, with the 10× CMC RL+APG treatment (Exp IV) achieving the highest average current intensity and moisture content, 1.31 and 1.12 times that of the control (CK), respectively, and a PAH removal of 106.02 mg·kg⁻¹. Biosurfactants also promoted bacterial growth in both contaminated soil and the biobarrier layer; the 10× CMC RL+APG treatment increased bacterial counts by 6.24-fold and 44.8%, respectively. However, excessive surfactant concentrations led to PAH accumulation in the biobarrier and clean soil. The 5× CMC RL+APG treatment provided optimal balance, maximizing PAH removal while maintaining barrier effectiveness. These findings confirm that appropriate biosurfactant concentrations can enhance EK-BB remediation, offering technical support for PAH-contaminated site remediation and safe reuse.

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Biosurfactant-Enhanced Electrokinetic-Biobarrier Remediation of Polycyclic Aromatic Hydrocarbon-Contaminated Soil from an Industrial Site

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202507095• Jan 15, 2026

Mechanical Properties and Microstructural Evolution of CO2-Mineralized Cured Steel Slag-Fly Ash Composite Cementitious Materials

Authors: REN Bin, JU, WANG Wei, FENG Xihao, SHI Junjie, ZHANG Changqing

This study investigates the optimization of CO2 mineralization curing on the performance of a ternary cementitious system comprising steel slag, fly ash, and Portland cement. Specimens were fabricated with varying residual water-to-cement ratios (r/w), steel slag and fly ash contents, curing pressures, and durations, then subjected to standard curing and CO2 mineralization curing. Compressive strength and carbon sequestration rate were measured, and X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to analyze mineral composition and microstructural evolution. Results indicate that compressive strength first increases then rapidly decreases with increasing residual water-to-cement ratio, with an optimal r/w below 0.15. Both compressive strength and carbon sequestration rate increase with higher steel slag content; the 50% steel slag + 10% fly ash formulation exhibited the highest values. Microstructural analyses revealed that CO2 mineralization primarily consumes hydration products such as Ca(OH)2, C-S(Al)-H, and AFt, generating abundant calcium carbonate that densifies the pore structure, thereby enhancing mechanical properties. Lower residual water-to-cement ratios, higher steel slag content, or extended curing durations increase the content and crystallinity of calcium carbonate. SEM observations confirmed the presence of densely packed, well-crystallized rhombohedral calcite in specimens with lower water-to-cement ratios and higher steel slag content. These findings provide a mechanistic basis for the engineering application of CO2 mineralization curing in ternary solid-waste cementitious materials.

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Mechanical Properties and Microstructural Evolution of CO2-Mineralized Cured Steel Slag-Fly Ash Composite Cementitious Materials

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202508041• Jan 15, 2026

Stress Responses and Accumulation Characteristics of Duckweed (Landoltia punctata) to Lead Oxide Nanoparticles

Authors: LAN Yan, GENG Heyan, YANG Guili

Lead oxide nanoparticles (PbO NPs) are increasingly released into aquatic environments from industrial processes, posing ecological risks. Duckweed (Landoltia punctata) is a known lead hyperaccumulator, but its physiological and biochemical responses to PbO NPs remain unexplored. This study synthesized PbO NPs via a plant-mediated biosynthesis method and exposed L. punctata to concentrations of 0 (control), 10, 20, 30, and 40 mg·L−1 in hydroponic culture for 7 days. Results showed concentration-dependent effects: low concentrations (10–20 mg·L−1) stimulated growth, while high concentrations (≥30 mg·L−1) inhibited fresh weight, growth rate, and root length. Chlorophyll b content decreased significantly at ≥20 mg·L−1 (by 14.09%, 10.79%, and 18.48% at 20, 30, and 40 mg·L−1, respectively), while carotenoid content increased. Malondialdehyde content and activities of superoxide dismutase, peroxidase, and catalase increased with PbO NPs concentration, indicating oxidative stress. Lead accumulation reached 1265.65 mg·kg−1 at 30 mg·L−1 and 2030.01 mg·kg−1 at 40 mg·L−1, with bioconcentration factors >1 and lead removal rates above 68.94%. Subcellular distribution showed lead predominantly in the cell wall fraction, followed by soluble components and organelles. These findings demonstrate that L. punctata exhibits strong PbO NPs accumulation and stress tolerance, supporting its use in phytoremediation of metal nanoparticle-contaminated waters.

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Stress Responses and Accumulation Characteristics of Duckweed (Landoltia punctata) to Lead Oxide Nanoparticles

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202508021• Jan 15, 2026

Characterization of Pollutants in Coal Chemical Industry Waste Salt and Its Resource Utilization Potential: A Case Study of a Coal Chemical Industrial Park in Northwest China

Authors: YANG Jun, HE Yi, LIU Yanping, WANG Nianxi, ZHOU Tianlai, LIU Guoliang, ZHENG Yang

Coal chemical industry waste salt, generated from high-salinity wastewater treatment, poses a bottleneck for green transformation under the 'dual carbon' strategy due to its low value and high complexity. This study investigated a typical coal chemical industrial park in Northwest China, using principal component analysis (PCA) on actual waste salt samples to identify pollutant characteristics and assess resource utilization potential. Results showed total organic carbon (TOC) ranged from 707.9 to 7,737.9 mg·kg⁻¹, with benzo(a)pyrene concentrations frequently exceeding the limits of the 'Identification Standards for Hazardous Wastes' (GB 5085.3). Hardness ions and metal ions also surpassed relevant product standards. PCA classified the waste salts into three types: sodium sulfate type, sodium chloride type, and high-complexity mixed salt, each corresponding to distinct resource utilization pathways. The study proposes differentiated technical routes based on PCA classification, providing a feasible reference for classified management and technology selection. This research supports the national policy of 'harmless pretreatment + resource utilization' for waste salt, contributing to green and high-quality development of the coal chemical industry.

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Characterization of Pollutants in Coal Chemical Industry Waste Salt and Its Resource Utilization Potential: A Case Study of a Coal Chemical Industrial Park in Northwest China

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202508050• Jan 15, 2026

Spatial Differentiation of Heavy Metals in a Landfill Site in a High-Altitude Cold Region Driven by Freeze-Thaw Cycles

Authors: ZHOU Zhongzhu, ZHOU Peng, ZHAO Yuzhu, HU Han, DENG Guochang, ZENG Mengyuan, CHEN Guanyi, DAN Zeng

This study investigated the spatial distribution and ecological risk of heavy metals (As, Cd, Cr, Cu, Ni, Pb, Zn) in soil beneath an informal waste dump in a pastoral area of Baingoin County, Nagqu City, Tibet, a high-altitude cold region with frequent freeze-thaw cycles. A total of 55 soil samples were collected from surface (0 cm), middle (10-30 cm), and deep (50 cm) layers. Single-factor index (Pi), geo-accumulation index (Igeo), Nemerow index (PN), and risk assessment code (RAC) were employed to evaluate contamination levels and potential ecological risks, while Kriging interpolation was used to map spatial distribution. Results showed that average concentrations of all seven heavy metals exceeded local background values. Horizontally, high-concentration zones were mainly located at five points within the dump. Vertically, Cd, Cu, Pb, and Zn were significantly enriched in the surface layer, whereas Ni exhibited higher concentrations in deeper layers, indicating downward migration driven by freeze-thaw processes. All evaluation methods identified Cd as the primary pollutant. Speciation analysis revealed that heavy metals were predominantly in the residual fraction, with Ni having the highest weak-acid-extractable fraction (5.55%), indicating strong mobility and potential biological toxicity. This study fills a gap in systematic research on informal waste dumps in high-altitude ecologically fragile areas and provides a case reference for environmental management and remediation of such sites in cold regions.

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Spatial Differentiation of Heavy Metals in a Landfill Site in a High-Altitude Cold Region Driven by Freeze-Thaw Cycles

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202507094• Jan 15, 2026

Strength and Microstructural Characteristics of Sludge Solidified by Loess-Based Composite Solidifying Agent

Authors: MA Xiaolei, BAI Xuemei, LI Jian, SHI Xujun, YE Shuaihua, JU, SHEN Zhiyuan, SHI Hongzhuang

To address land waste and poor bearing capacity from sludge landfill, this study developed a composite solidifying agent using loess, fly ash, desulfurized gypsum, and cement. Orthogonal experiments combined strength testing, SEM/XRD microanalysis, permeability and heavy metal leaching tests, and cost accounting. Results show that cement significantly enhances early and mid-term strength, while loess dominates later strength development. Optimal fly ash and desulfurized gypsum content is 12% each. The optimal mix ratio (loess:fly ash:desulfurized gypsum:cement:sludge) is 0.1:0.12:0.12:0.08:1. The solidified matrix forms dense structures via C-S-H gel and ettringite (Aft), effectively controlling heavy metal leaching at low cost. This work enables solid waste resource utilization and provides robust support for sludge solidification engineering.

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Strength and Microstructural Characteristics of Sludge Solidified by Loess-Based Composite Solidifying Agent

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202508047• Jan 15, 2026

Multi-stage Activation of Fly Ash for Al(OH)3 Extraction: Process Optimization and Mechanistic Insights

Authors: ZHOU Yan, WEI Cong, SHI Haoyang, YAN Xinyi, QU Jihu, LIN Jing

Selective recovery of aluminum compounds from fly ash is a key route for its high-value utilization. This study developed a multi-stage activation process for extracting Al(OH)3 from fly ash, comprising mechanical activation, calcination activation, chemical separation, and carbonation precipitation. Fly ash was mixed with carbide slag and CaF2, then calcined; the resulting clinker was leached with Na2CO3 solution to extract Al. The CaO generated from high-temperature calcination of carbide slag facilitated the separation of Si and Al. After solid-liquid separation, CO2 was introduced into the Al-rich leachate to precipitate Al(OH)3. The process promoted the formation of Ca12Al14O32F2 and inert Ca2SiO4, achieving efficient Si-Al separation during calcination. Under optimal conditions (mechanical activation for 60 min, 4% CaF2, calcination at 1000°C for 2 h, leaching with 40 g/L Na2CO3), the Al extraction rate reached 91.8%, and the product purity was 98.9%. The alumina extraction residue exhibited porous and highly reactive characteristics, suitable for producing flame-retardant materials or high-value silicon-based products (e.g., white carbon black, molecular sieve adsorbents). The process offers a promising industrial route for fly ash valorization, with potential integration with cement production lines for synergistic CO2 capture and utilization.

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Multi-stage Activation of Fly Ash for Al(OH)3 Extraction: Process Optimization and Mechanistic Insights

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202508084• Jan 15, 2026

Mechanical Properties and Pore-Forming Mechanism of Porous Ceramsite Prepared from Multi-Source Granite Solid Waste

Authors: JIN Jiaxu, JU, QIU Xiaolei, WANG Ping, LIU Lei, WU Pengfei

Granite mining areas generate large quantities of abandoned soil and rock powder, posing environmental challenges and resource waste. This study investigates the synergistic preparation of porous ceramsite from two typical granite solid wastes—weathered granite soil (high Al2O3) and granite waste rock powder (high SiO2)—with waste glass powder as a fluxing agent. Single-factor experiments and response surface methodology (Box-Behnken) were employed to optimize the process and elucidate the pore-forming mechanism. The optimal conditions were a mass ratio of weathered granite soil:granite waste rock powder:waste glass powder of 5.6:2.4:2, a preheating temperature of 480 °C, a sintering time of 32 min, and a sintering temperature of 1140 °C. Under these conditions, the resulting porous ceramsite achieved a compressive strength of 1.74 MPa. The ceramsite effectively immobilized heavy metals, ensuring environmental safety. This research demonstrates that multi-component complementarity and multi-factor coupling optimization can produce porous ceramsite with favorable mechanical properties and stable pore structure, providing a theoretical basis and technical support for high-value utilization of granite solid waste.

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Mechanical Properties and Pore-Forming Mechanism of Porous Ceramsite Prepared from Multi-Source Granite Solid Waste

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202509009• Jan 15, 2026

Two-Phase Flow Characteristics of a Jet Aerator with Built-in Porous Thin Plates

Authors: WU Yao, HAN Leng, LI Aoqi, XI Wenjun, ZHANG Shinan, ZHANG Anlong

Air-supplied jet aerators, combining hydraulic jet and gas induction principles, are critical equipment in aerobic biological wastewater treatment. However, low energy conversion efficiency and insufficient local gas-liquid mixing are core bottlenecks limiting their competitiveness. A three-dimensional flow field analysis method for jet aerators was developed based on the k-ε turbulence model and Euler-Euler multiphase flow model. The effects of different orifice plate distributions, shapes, sizes, hole numbers, and installation positions on average pressure, turbulent kinetic energy, and turbulent dissipation rate were systematically studied. Results show that the asterisk-shaped orifice plate yields the highest gas-liquid two-phase turbulent mixing intensity, followed by the annular shape, while the parallel arrangement yields the lowest. With increasing hole number and single-hole size, average pressure, velocity, turbulent kinetic energy, and turbulent dissipation rate for different plate shapes initially fluctuate downward and then stabilize. When the number of triangular holes is 9, mass transfer efficiency is significantly enhanced, and overall aerator performance is excellent. When the triangular hole diameter is 7 mm, the device achieves an optimal match between energy utilization and mixing efficiency across pressure distribution, velocity field, turbulent kinetic energy, and dissipation rate. The farther the porous thin plate is installed from the sewage nozzle, the further gas-liquid two-phase turbulence is enhanced. Experiments confirm that the boundary layer is fully developed, liquid and air are thoroughly mixed, and the orifice plate promotes bubble breakup and refinement through throttling and collision, significantly improving oxygen transfer efficiency. This research provides a theoretical basis and technical support for the transformation and upgrading of aeration technology towards high efficiency and low carbon, and for extending equipment service life.

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Two-Phase Flow Characteristics of a Jet Aerator with Built-in Porous Thin Plates

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202508052• Jan 15, 2026

Numerical Simulation of the Performance of a Channel-Steel Baffle-Type Pre-Dust Collector for Biomass Boiler Flue Gas

Authors: YE Xinglian, ZHANG Chucheng, SU Yinbiao, LAI Huicai, AN Xizhong, LIN Chunyuan

To improve the performance of pre-dust collectors in biomass boiler flue gas purification systems, a novel channel-steel baffle-type pre-dust collector was proposed to address the low collection efficiency of conventional designs. A gas-solid two-phase flow model was developed within the MP-PIC (multiphase particle-in-cell) framework and validated against physical experiments. The model simulated gas-particle motion inside the collector, systematically investigating the effects of structural modifications, flue gas conditions, and dust properties on collection efficiency and pressure drop. Results indicate that adding a flow baffle in the ash hopper and adopting an upper-inlet flue duct enhance collection efficiency with negligible impact on pressure drop. Flue gas velocity significantly influences performance: increasing velocity reduces efficiency while raising pressure drop; an optimal design velocity of 1.0–2.0 m·s−1 is recommended. Elevated flue gas temperature slightly decreases both efficiency and pressure drop, with minimal impact over a range of tens of degrees Celsius. Higher dust density and larger particle size improve collection efficiency and reduce pressure drop, whereas higher dust concentration increases both efficiency and pressure drop. The study elucidates the mechanisms by which structural and operational parameters affect pre-dust collector performance, providing theoretical guidance for designing low-resistance, high-efficiency collectors for biomass boilers.

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Numerical Simulation of the Performance of a Channel-Steel Baffle-Type Pre-Dust Collector for Biomass Boiler Flue Gas

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Original ResearchVol. 20, Issue 4 • pp. 100-112DOI: 10.12030/j.cjee.202510028• Jan 15, 2026

Aging Mechanism of Microplastics in UV/Persulfate System and Its Effect on Norfloxacin Adsorption Behavior

Authors: ZHOU Fuya, WANG Yanan, XIE Jincheng, DENG Qiheng, LI Hao

This study investigates the aging mechanism of polystyrene microplastics (PS MPs) induced by ultraviolet (UV)-activated potassium persulfate (KPS) and its influence on the adsorption of norfloxacin (NOR). Results show that aged PS exhibited yellowing, increased surface roughness and specific surface area, enhanced oxygen-containing functional groups, and elevated negative surface charge, along with the generation of environmentally persistent free radicals (EPFRs). Compared with UV alone, UV+KPS induced more pronounced aging due to the generation of reactive oxygen species (ROS) including hydroxyl radicals (·OH) and superoxide radicals (O2·−). Adsorption kinetics and isotherm data revealed that UV+KPS-aged PS significantly enhanced NOR adsorption, with a maximum adsorption capacity of (2.539±0.032) mg·g−1, which was 4.20 times higher than that of pristine PS. The adsorption mechanism was governed by hydrogen bonding, electrostatic interactions, and pore filling. Solution pH modulated the electrostatic interactions by affecting NOR speciation and PS surface charge, thereby influencing NOR adsorption. This study systematically reveals the accelerated aging of coexisting MPs and EPFRs generation during UV+KPS treatment, contributing to a comprehensive understanding of MPs environmental behavior and potential ecological risks.

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509078• Jan 15, 2026

Research Progress on Recycling Technologies for Retired Photovoltaic Modules

Authors: LI Yamin, ZHAO Guangjin, ZHANG Yunxiao, DONG Ruifeng, HU Yuxia, ZHANG Shaofeng

The rapid expansion of photovoltaic (PV) installations and the impending retirement of early-stage modules have made the recycling of end-of-life PV modules an urgent issue. This review systematically examines the types and structures of retired PV modules, with a focus on crystalline silicon (c-Si) and thin-film technologies. It critically evaluates the principles, processes, and pros and cons of physical, chemical, pyrolysis, biological, combined, and emerging methods for recovering c-Si modules. The current status of silicon, metal, and valuable component recovery processes is summarized. For thin-film modules, the core technologies for recovering valuable components via pyrometallurgical, hydrometallurgical, biological, and novel approaches are analyzed in depth. Results indicate that conventional methods (physical, chemical, pyrolysis) remain dominant but suffer from high energy consumption, pollution, and chemical usage. Emerging technologies such as biological and green leaching are identified as key research directions, though they face challenges of low technical maturity and high costs. Finally, policy orientations and existing challenges are discussed, and future development directions are proposed, providing significant guidance for the sustainable and large-scale green development of the PV industry.

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Research Progress on Recycling Technologies for Retired Photovoltaic Modules

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509051• Jan 15, 2026

Comparative Analysis of Greenhouse Gas Emission Factors for Recyclables from Municipal Solid Waste

Authors: YANG Xuerui, LU Tao, LV Fan, ZHANG Hua, HE Pinjing

Recyclables constitute a significant fraction of municipal solid waste (MSW) and hold substantial potential for resource utilization and greenhouse gas (GHG) emission reduction, contributing to carbon peak and carbon neutrality goals. However, reported GHG emission factors (EFs) for various recyclables vary widely across databases and literature, ranging from -19,110 to -125 kgCO2-eq·t⁻¹, with significant differences both among categories and within the same category, complicating accurate accounting. This study systematically integrates literature data on EFs for different recyclable categories, focusing on identifying factors causing intra-category variability. Data were collected from global databases (ecoinvent, WARM, CPCD, NAEI) and peer-reviewed studies over the past two decades, normalized to a functional unit of 1 tonne of recyclable. Statistical analysis (mean ± standard deviation) provided reference ranges for each category. Results show paper recyclables EFs range from -3,140 to 270 kgCO2-eq·t⁻¹, with corrugated cardboard and writing paper exhibiting higher absolute values than packaging paper due to structural strength and resource value. Plastic recyclables EFs range from -3,096 to -566 kgCO2-eq·t⁻¹, with EPS showing the highest reduction potential, followed by PET and PVC, then HDPE, LDPE, PP, and other plastics. Key influencing factors include functional unit definition, accounting scenario, system boundary, electricity emission factor selection, and calculation assumptions. The study recommends selecting EFs matching the specific accounting scenario and performing error analysis. Data gaps remain for LDPE, EPS, and other plastics, necessitating further experimental or field data. To enhance accuracy, calibration methods such as process-level and life-cycle inventory data calibration are proposed. This work provides a scientific basis for EF selection and calibration in GHG accounting of recyclables.

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Comparative Analysis of Greenhouse Gas Emission Factors for Recyclables from Municipal Solid Waste

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509039• Jan 15, 2026

Recycling Pathways and Carbon Benefit Reconfiguration of Decommissioned Wind Turbine Blades

Authors: CAI Chouai, LI Xia, WU Chunran, FANG Le, ZHANG Cheng, KOU Shicong

Under the dual-carbon strategic goal, China's wind power installed capacity continues to grow rapidly, making the low-carbon recycling of decommissioned wind turbine blades increasingly prominent. This study systematically reviews material recovery pathways, policy support systems, and life-cycle carbon benefits of decommissioned blades. It first analyzes regional distribution and unit characteristics of wind power installations, identifying differentiated challenges in dismantling, transportation, and reuse across regions. Subsequently, it compares mechanical/physical, pyrolysis, chemical, and combined recycling technologies. Results show that mechanical/physical methods are low-cost but yield fiber retention rates of only 10%–78%; pyrolysis has reached industrial scale but exhibits high carbon emission intensity; chemical methods achieve higher fiber retention (55%–96%) with potential carbon reduction advantages; combined methods overcome single-technology limitations, achieving fiber retention exceeding 95%, demonstrating potential for high-value utilization and low-carbonization. At the policy level, China has proposed a two-stage target: initially establishing a blade recycling responsibility mechanism by 2025 and forming industrial clusters by 2030, with gradual improvements in standards and incentives. Life-cycle assessment indicates that wind power has slightly higher global warming potential (GWP) than photovoltaics, but its emissions are mainly concentrated in component manufacturing; if efficient recycling is achieved, wind power could surpass photovoltaics in full life-cycle carbon benefits. In summary, promoting efficient recycling and policy coordination for decommissioned wind turbine blades can achieve dual benefits of resource recycling and carbon reduction, providing strong support for reconstructing a sustainable renewable energy development paradigm.

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Recycling Pathways and Carbon Benefit Reconfiguration of Decommissioned Wind Turbine Blades

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509093• Jan 15, 2026

Insights from the EU Green Claims Directive and Related Policies for Carbon Dioxide Removal in China

Authors: HOU Yunlu, CAI Bofeng, LI Qi, PANG Lingyun, LIU Guizhen, GUO Jing, ZHONG Yiyan

Amid intensifying global warming, carbon emission reduction and carbon dioxide removal (CDR) have become central to climate governance. In March 2023, the European Commission proposed the Green Claims Directive (GCD) to combat greenwashing and enhance the reliability, comparability, and verifiability of environmental claims. The GCD, together with the Empowering Consumers for the Green Transition Directive, the Carbon Removal Certification Framework, and the European Sustainability Reporting Standards, forms a policy cluster supporting the EU's green transition and CDR deployment. China, as a major greenhouse gas emitter, has made progress in renewable energy and national carbon market construction, yet its total emissions remain high, CDR technologies are nascent, and CCUS deployment is economically oriented, mainly in enhanced oil recovery. This study systematically reviews the legislative background, core objectives, and synergistic logic of the GCD and related policies, focusing on requirements for CDR certification, third-party verification, and carbon credit regulation. It compares Chinese and EU carbon markets in coverage, allowance allocation, and MRV systems. The analysis indicates that EU experience in policy integration, technical standardization, and market maturity can inform China's policy framework, technology pathways, and market efficiency, supporting large-scale CDR and the 'dual carbon' goals.

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Insights from the EU Green Claims Directive and Related Policies for Carbon Dioxide Removal in China

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509049• Jan 15, 2026

Comparative Optimization and Equipment Development of Enrichment and Concentration Methods for SARS-CoV-2 in Wastewater from Inbound Flights

Authors: YU Haoxiang, YU Guangshuai, WU Jiayu, WANG Xin, YANG Min, TIAN Zhe, LI Qing, ZHANG Jingyi, SHI Yingyue

This study systematically compared three virus enrichment and concentration methods—polyethylene glycol (PEG) precipitation, aluminum salt coagulation, and centrifugal ultrafiltration—for detecting SARS-CoV-2 in high-turbidity, high-strength wastewater from inbound flights. The aluminum salt coagulation method exhibited the best overall performance, achieving an average recovery rate of 25.95% for SARS-CoV-2 pseudovirus, significantly higher than PEG precipitation (12.91%) and centrifugal ultrafiltration (0.22%) (P<0.05). Its detection limit reached 10 copies·mL⁻¹, whereas centrifugal ultrafiltration suffered severe membrane fouling, limiting detection to 1,000 copies·mL⁻¹. Considering the high pH buffering of flight wastewater, the aluminum salt method was optimized by adjusting pH to 6.00±0.4, employing rapid magnetic stirring, and reducing mixing time to 1 minute, yielding an average recovery of 27.56% (not significantly different from the original 25.95%, P>0.05). An automated enrichment device was developed based on the optimized method, reducing processing time per sample from 115 min to 60 min while maintaining comparable recovery and improved repeatability. Applied to 1,309 wastewater samples from inbound flights between January 2024 and May 2025, the average detection rate of SARS-CoV-2 was 45.45%, with trends consistent with national COVID-19 epidemiological data. The automated device demonstrates suitability for routine surveillance, providing technical support for port epidemic prevention.

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Comparative Optimization and Equipment Development of Enrichment and Concentration Methods for SARS-CoV-2 in Wastewater from Inbound Flights

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202510039• Jan 15, 2026

Life-Cycle Carbon Footprint Assessment and Emission Reduction Strategy Analysis of Ship Supply Chains

Authors: HAN Zinuo, LIN Shuangjiao, PAN Fubin

The shipping industry's carbon emissions have drawn increasing attention. This study quantifies the carbon footprint of ship supply chains across their life cycle to identify key emission stages and reduction potentials, promoting green transformation. Based on life-cycle theory and using process analysis, a carbon footprint assessment model was constructed covering raw material acquisition, construction and assembly, transportation and distribution, and scrapping and recycling. The model was applied to a case ship, followed by multi-scenario and sensitivity analyses. Results show that the transportation and distribution stage is the dominant source of positive emissions, accounting for 88.73% of the total, while the scrapping and recycling stage provides a carbon offset benefit of 6.77%. Among five emission reduction scenarios—low-carbon materials, green energy, green logistics, circular economy, and comprehensive low-carbon—the reduction efficiencies are 2.02%, 0.06%, 18.44%, 0.42%, and 20.95%, respectively, indicating that green logistics is the core pathway for decarbonizing ship supply chains. Under the green logistics scenario, optimizing the LNG carbon emission factor yields more significant reduction effects. This study provides a life-cycle perspective on the carbon footprint structure of ship supply chains, offering theoretical references for identifying key reduction links and optimizing low-carbon technology pathways.

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Life-Cycle Carbon Footprint Assessment and Emission Reduction Strategy Analysis of Ship Supply Chains

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202506064• Jan 15, 2026

Electrocatalytic Oxidation Performance and Mechanism of Porous Active Metal Oxide Coated Anode for Congo Red Degradation

Authors: HUANG Zijiao, WEI Jiaqi, KONG Xinyi, CUI Jiayi, ZHANG Yuanyuan, WEI Qiaoyan, ZHENG Junjian, JU

To address the challenges of high salinity, recalcitrance, limited mass transfer, and coating detachment in traditional anodes for textile wastewater treatment, a porous RuO2@r-TiO2 nanotube array (NTA) anode was fabricated via anodic oxidation, electrochemical reduction, and thermal decomposition. A flow-through electrochemical oxidation system was constructed using this anode and a graphite felt cathode. The material's morphology and physicochemical properties were characterized by SEM, XRD, and XPS. Congo red (CR) was used as a model pollutant to evaluate degradation performance under various conditions. Optimal conditions were identified as current density 5 mA·cm−2, permeate flux 480 L·(m2·h)−1, initial CR concentration 0.15 mmol·L−1, and NaCl concentration 75 mmol·L−1. Under these conditions, the system achieved 91% decolorization within 20 min and 82% mineralization within 60 min. Mass transfer tests showed a rate constant of 2.23×10−4 m·s−1 in flow-through mode, three times higher than conventional mode, with active chlorine and H2O2 production increased by 32.8% and 66.7%, respectively. Radical quenching experiments indicated that singlet oxygen (1O2) was the primary reactive species. The degradation mechanism was proposed based on quenching and UV spectral analysis. The system achieved >90% decolorization for five typical dye pollutants with an energy consumption of only 0.16 kWh·m−3. Cyclic voltammetry confirmed long-term stability. These findings provide theoretical support for applying electrochemical advanced oxidation to high-salinity textile wastewater.

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509020• Jan 15, 2026

Effect of Three-Stage Reflux Ratio on the Performance of AAOA-MBR Process for Municipal Wastewater Treatment

Authors: TAN Xiaoping, KUANG Ke, YE Junwei, LIANG Zhenhao, WANG Ziyuan, LIN Dachao, DU Xing, SONG Wei, JU (first author: TAN Xiaoping; corresponding author: SONG Wei)

The AAOA-MBR (anaerobic-anoxic-oxic-anoxic membrane bioreactor) process is widely used in municipal wastewater treatment, but its multi-stage internal recirculation complicates sludge retention time (SRT) and carbon source distribution. This study systematically regulated three reflux ratios (R1: membrane tank to oxic tank; R2: oxic tank to anoxic I tank; R3: anoxic II tank to anaerobic tank) in a pilot-scale system (0.24 m3·d−1) to reveal their effects on nutrient removal and membrane fouling. When R1:R2:R3 = 300%:200%:100%, effluent COD, TN, TP, and NH3-N met discharge standards. Reducing R1 and R2, thereby decreasing total reflux ratio from R=6 to R=3, shortened SRT, which suppressed nitrifier accumulation and increased effluent COD and TN, but decreased TP. High-throughput sequencing of anoxic I and oxic tanks showed that denitrifying bacteria (Thauera and Ottowia) relative abundances decreased from 0.68% to 0.42% and 0.51% to 0.24%, respectively, while the phosphorus-accumulating organism Candidatus_Accumulibacter increased from 0.78% to 1.12%, enhancing phosphorus removal. Additionally, lowering R1 to 200% caused sludge accumulation in the membrane tank, exacerbating membrane fouling. Thus, internal recirculation ratios must be adjusted based on influent characteristics to balance nutrient removal and membrane performance.

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Effect of Three-Stage Reflux Ratio on the Performance of AAOA-MBR Process for Municipal Wastewater Treatment

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202510013• Jan 15, 2026

Spatiotemporal Distribution of Nutrients and Chlorophyll-a in Dongping Lake Based on Delft3D Modeling

Authors: LONG Lan, HUO Shouliang, ZHANG Jingtian, ZHANG Han, SHI Zhanyao, ZHANG Hanxiao, JU ...

To investigate the spatiotemporal distribution of nutrients and chlorophyll-a (Chl-a) in Dongping Lake, a coupled hydrodynamic-water quality-ecological model was developed using Delft3D. The model simulated total nitrogen (TN), nitrate nitrogen (NO3-N), ammonia nitrogen (NH4-N), total phosphorus (TP), soluble reactive phosphorus (SRP), and Chl-a. After validation, the model systematically analyzed the spatiotemporal patterns and influencing factors, revealing nitrogen and phosphorus transformation pathways. Results showed three temporal phases: relatively stable concentrations from January to April, significant fluctuations from May to August, and gradual stabilization from September to December, with peak timing varying among indicators. Spatially, concentrations were generally higher in the south and lower in the north, but NH4-N, TP, and Chl-a exhibited reverse patterns (higher in north) during certain periods. External inputs, primarily from the Dawen River, dominated the overall distribution, while water temperature, dissolved oxygen, and hydrodynamic conditions further modulated internal variability. Nitrogen and phosphorus showed distinct fates: nitrogen was primarily removed via denitrification and anammox, whereas phosphorus tended to transform into particulate forms and remained in the lake for extended periods. These findings provide scientific support for precise water quality management in Dongping Lake.

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Spatiotemporal Distribution of Nutrients and Chlorophyll-a in Dongping Lake Based on Delft3D Modeling

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202511051• Jan 15, 2026

Mechanistic Study on Photosynthetic Bacteria Granulation under Synergistic Hydraulic and Organic Loading

Authors: ZHU Dengming, WU Yifan, WANG Huiyue, AN Fupeng, LU Haifeng, ZHANG Guangming

Photosynthetic bacteria (PSB) wastewater treatment technology is promising for simultaneous pollutant removal and resource recovery (e.g., single-cell protein, hydrogen). However, poor cell hydrophobicity and aggregation lead to low biomass retention and short sludge retention time, hindering engineering application. This study investigated the driving role and mechanism of upflow velocity as a key hydraulic selection pressure on PSB granulation under stepwise increasing organic loading rate (OLR). In laboratory up-flow photobioreactors (UPBR), comparative experiments were conducted with macro-index monitoring and micro-mechanism analysis. Results showed that under high upflow velocities of 3.00–6.30 m·h−1, PSB granular sludge with an average diameter of 285.58 μm and excellent settleability (sludge volume index, SVI = 22.73 mL·g−1) was successfully formed within approximately 60 days. Compared to the control, the granules in the experimental group were larger, with clear boundaries and compact structure, and significant enrichment of filamentous bacteria was observed. Mechanism analysis indicated that OLR provided nutritional driving force for microbial growth, while upflow velocity supplied high hydraulic shear force, physically screening and enriching settleable aggregates, and specifically inducing secretion of hydrophobic tryptophan-like proteins and humic acids (key extracellular polymeric substances, EPS). Additionally, core genera such as Xanthobacteraceae, possessing stress tolerance and EPS secretion functions, were enriched. This study reveals a chain mechanism of 'physical selection–biological response' centered on hydraulic selection, demonstrating that upflow velocity is a key controllable factor for PSB granulation, providing theoretical basis and technical pathway for solving PSB biomass washout and promoting resource-oriented treatment of high-strength organic wastewater.

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Mechanistic Study on Photosynthetic Bacteria Granulation under Synergistic Hydraulic and Organic Loading

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202508081• Jan 15, 2026

Low-Temperature Thermal Remediation of Naphthalene-Contaminated Soil Using Cu–CeOx/TiO2 Trimetallic Catalysts

Authors: XUAN Yuning, YU Jintao, ZHANG Changbo, MA Xiaoyu, TANG Xiaoyong, CAO Xinyu, XU Haitao, LYU Shuguang, LIU Yuhao

Traditional soil thermal remediation requires high temperatures (>300 °C), which can damage soil structure, increase energy consumption, and elevate carbon emissions. This study developed a Cu–CeOx/TiO2 trimetallic catalyst to enable low-temperature thermal remediation of naphthalene-contaminated soil. Using nano-TiO2 as a support, catalysts with varying Cu/Ce ratios were prepared via impregnation-calcination. Material characterization (XRD, TEM, XPS, etc.) revealed that Cu and Ce incorporation induced crystal defects in TiO2, enhancing lattice oxygen activity and electron mobility, thereby generating more oxygen vacancies and hydroxyl radicals. Performance evaluation using a TGA-GC-FTIR-MS platform showed that the catalyst with Cu:Ce = 1:1 achieved the best remediation efficiency, reducing the thermal remediation temperature from 250 °C to 211.5 °C and increasing the removal rate by an average of 19.49% compared to the non-catalyst group at the same temperature. The catalyst facilitated stepwise degradation of naphthalene into smaller organic molecules (alcohols, carboxylic acids, aldehydes) and ultimately into H2O and CO2. This work demonstrates that Cu–CeOx/TiO2 significantly lowers the energy demand of thermal remediation, offering a promising approach for low-carbon remediation of organic-contaminated soils.

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Low-Temperature Thermal Remediation of Naphthalene-Contaminated Soil Using Cu–CeOx/TiO2 Trimetallic Catalysts

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509047• Jan 15, 2026

Simulation and Prediction of Vegetation Carbon Flux under SSP Scenarios in Beijing

Authors: ZHOU Yuci, LIU Chenchen, WANG Xiaoxuan, LI Wei, ZHAO Bo, GUO Junhong, JU

To reveal the dynamic characteristics of ecosystem carbon flux and its response to meteorological factors, this study employed the Biome-BGC model to simulate gross primary productivity (GPP) and net primary productivity (NPP) of vegetation in Beijing for historical (2001–2014) and future (2051–2070) periods under SSP126 and SSP585 scenarios, using multi-source data including regional meteorology, vegetation type, and soil texture. The Mann-Kendall (M-K) test and Empirical Orthogonal Function (EOF) analysis were applied to examine spatiotemporal patterns and carbon use efficiency (CUE). Results indicate that Biome-BGC accurately reproduces historical carbon flux characteristics. Temporally, annual mean GPP and NPP exhibited fluctuating upward trends, ranging from 584 to 777 g C m−2 a−1 and 238 to 388 g C m−2 a−1, respectively. Spatially, GPP and NPP displayed both same-phase and opposite-phase distribution patterns. Annual mean temperature was the dominant factor influencing GPP and NPP trends, followed by solar radiation and precipitation. Under future scenarios, both GPP and NPP are projected to increase, with SSP585 showing greater enhancement. By 2070, GPP is expected to rise by 171 and 376 g C m−2 a−1 under SSP126 and SSP585, respectively, while NPP increases by 71.8 and 137 g C m−2 a−1. The spatial distribution of GPP and NPP exhibits a 'low-center, high-periphery' pattern, with multi-year means of 969 and 425 g C m−2 a−1. Future CUE is approximately 0.45, indicating substantial carbon sequestration potential of Beijing's vegetation under climate change.

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Simulation and Prediction of Vegetation Carbon Flux under SSP Scenarios in Beijing

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509019• Jan 15, 2026

Enhanced Performance of Bioelectrochemical Systems Using Natural Source Materials for Methyl Orange Wastewater Treatment

Authors: WANG Xinyao, WANG Haiman, WANG Guiqiang, ZHANG Shuyue

To enhance the electricity generation and decolorization efficiency of bioelectrochemical systems (BES) for azo dye wastewater, this study introduced pomelo peel biochar as anode material and flavonoid-rich Chinese herbal medicines as electron mediators (EMs) into microbial fuel cells (MFCs). The anodes were prepared by chemical activation with KOH, ZnCl2, and H3BO3, followed by polypyrrole (PPy) modification. Among the modified anodes, PPy-PPCH3BO3-CC exhibited the best electrochemical performance. The EMs were derived from aqueous extracts of Scutellaria baicalensis (Huangqin), Ginkgo biloba leaves, and Pueraria lobata (Gegen). The extract from Scutellaria baicalensis showed the highest electron transfer capability. In the MFC system equipped with the optimal anode and Scutellaria baicalensis extract, the maximum output voltage reached (587±10) mV, power density increased to 423.12 mW·m−2, Coulombic efficiency was (57.85±1.06)%, COD removal efficiency was (77.45±0.92)%, charge transfer resistance (Rct) decreased to 7.15 Ω, and methyl orange decolorization rate reached (95.86±1.12)%. These results were significantly superior to the control group, demonstrating that natural source materials can effectively enhance the performance of BES for methyl orange wastewater treatment.

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Enhanced Performance of Bioelectrochemical Systems Using Natural Source Materials for Methyl Orange Wastewater Treatment

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509086• Jan 15, 2026

Continuous Performance of Permeable Reactive Columns Combining ZVI/FeS2 with Microorganisms for Removal of Nitrate and Ofloxacin from Water

Authors: LI Zhou, XIN Xinju, LIU Xin, CHEN Fangfang, LUO Jing, RAN Jing, SHI Qianqian, WEN Yu

Groundwater contamination by nitrate and antibiotics has become a global concern. This study evaluated the continuous performance of permeable reactive barrier (PRB) columns packed with zero-valent iron (ZVI) and pyrite (FeS2) combined with denitrifying microorganisms (ZFM) for simultaneous removal of nitrate and ofloxacin (OFL). Control columns included soil (S), microorganisms (M), and ZVI/FeS2 (ZF). Over 30 days of continuous operation, the ZFM column achieved average removal efficiencies of 88% for nitrate and 78% for OFL, significantly higher than controls. The ZFM system maintained higher active iron concentration (0.68 mg·L−1) compared to ZF (0.48 mg·L−1), mitigated pH increase, and sustained lower oxidation-reduction potential (ORP), favoring stable performance. XRD and XPS analyses revealed that microbial involvement promoted FeS formation (2θ=30.1°) and reduced ZVI passivation, extending material lifespan. High-throughput sequencing showed that while overall microbial diversity remained stable, key functional populations including norank_f_Fermentibacteraceae, norank_f_Anaerolineaceae, Longilinea, and Anaerolinea increased in abundance by 2.93%, 0.55%, 1.53%, and 0.62%, respectively, enhancing nitrate and OFL removal. These findings demonstrate that integrating microorganisms with ZVI/FeS2 in PRB systems offers a promising approach for remediating combined nitrate and antibiotic contamination in groundwater.

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Continuous Performance of Permeable Reactive Columns Combining ZVI/FeS2 with Microorganisms for Removal of Nitrate and Ofloxacin from Water

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509067• Jan 15, 2026

Occurrence Characteristics, Source Analysis, and Beach Quality Assessment of Marine Litter in Daya Bay

Authors: LIU Bingjie, LU Yao, YE Kuangmin, LI Guodong, DENG Hanqiang, SUN Kaifeng, JU ...

Marine litter poses a significant threat to coastal ecosystems globally, necessitating a comprehensive understanding of its multi-compartment distribution and driving mechanisms for effective management. This study investigated the occurrence, composition, and sources of beach, sea surface, and seafloor litter in the northeastern Daya Bay, a semi-enclosed bay, during August–October 2024. Sampling included 11 beach transects, 6 surface transects, and 25 seafloor transects. Results showed that the mean density of large and very large beach litter was 4.41×10^5 items·km−2, while medium beach litter reached 5.39×10^6 items·km−2. Surface litter densities were 5.82×10^2 and 9.90×10^3 items·km−2 for large/very large and medium fractions, respectively. Seafloor litter averaged 5.20×10^3 items·km−2. Plastics dominated all compartments, accounting for 74.0% (beach), 96.0% (surface), and 78.8% (seafloor) of total litter. Source apportionment using NOWPAP methodology indicated that beach and surface litter primarily originated from coastal recreational activities, whereas seafloor litter was mainly derived from shipping and fishing. Beach quality assessment revealed that 63.6% of beaches were moderately clean or better (grade II–IV), and 90.9% were moderately safe or better (grade I–III). Hotspots included tourism beaches, tidal gyre areas, coral reef zones, and fishing grounds. The study underscores the need for targeted management, including improved waste collection on tourist beaches, dynamic cleaning protocols, and port reception facilities for fishing waste.

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Occurrence Characteristics, Source Analysis, and Beach Quality Assessment of Marine Litter in Daya Bay

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202511034• Jan 15, 2026

Elimination of Matrix Effects in Ionizing Radiation Treatment of Cephalosporin Wastewater by Pretreatment Coupling

Authors: ZHANG Yanru, ZHAO Zhen, XIA Tao, QI Buriju

Ionizing radiation (IR) is an emerging advanced oxidation process for degrading recalcitrant organic pollutants in water, but its efficiency is often hampered by matrix effects from coexisting substances in real wastewater. This study coupled three pretreatments—coagulation sedimentation, adsorption, and biological oxidation—with electron beam IR to treat a model cephalosporin wastewater containing cefotaxime sodium (CTX) and typical coexisting components. The results showed that all coupled systems significantly improved treatment performance compared to direct IR: COD removal increased by 19%–42% and CTX removal by 8.4%–19%. Under the tested conditions, the optimal coagulant was polymeric ferric sulfate (PFS), the optimal adsorbent was activated carbon, and the optimal aeration time for biological oxidation was 6 h. All three pretreatments reduced matrix effects, with adsorption, biological oxidation, and coagulation sedimentation lowering the matrix effect by 17%, 11%, and 9%, respectively. Quantum chemical calculations and LC-MS analysis predicted radical reaction sites on CTX and revealed five possible degradation pathways. The study demonstrates that pretreatment-IR coupling is an effective strategy to mitigate matrix effects and enhance the targeted degradation of antibiotics in complex wastewater matrices.

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Elimination of Matrix Effects in Ionizing Radiation Treatment of Cephalosporin Wastewater by Pretreatment Coupling

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509124• Jan 15, 2026

Water Quality Assessment and Driving Mechanism Analysis of the Hanjiang River Basin Based on WQI-PCA-OPGD

Authors: YAO Shiyang, WANG Shiqi, HE Jiaojie, JU, ZHANG Jingxin, ZHAO Xiaohong, TIAN Na, YANG Liwei

To reveal the spatiotemporal evolution and driving mechanisms of water quality in the Hanjiang River Basin, this study utilized monthly water quality monitoring data from 54 sections from January 2021 to April 2024. Methods including single-factor index, comprehensive water quality index (WQI), principal component analysis (PCA), and optimal parameters-based geographical detector (OPGD) were employed. Results indicated significant spatiotemporal differences, with total nitrogen (TN), chemical oxygen demand (COD), and permanganate index (CODMn) as major pollutants, TN being the most critical. Temporally, agricultural non-point source organic pollution dominated in wet season, while comprehensive organic pollution with industrial point source characteristics prevailed in dry season. Spatially, water quality deteriorated along the main stream, with tributary downstream areas showing severe pollution, forming a pattern of 'mountainous areas good, plains poor'. OPGD revealed combined effects of natural conditions and human activities, proposing a 'zonal control and targeted treatment' strategy.

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Water Quality Assessment and Driving Mechanism Analysis of the Hanjiang River Basin Based on WQI-PCA-OPGD

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509026• Jan 15, 2026

Adaptive Characteristics of Paulownia fortunei to Rocky Desertification Habitats and Its Effects on Soil Properties

Authors: TAN Xiongzhong, LUO Honglei, WU Jiaxin, LIU Lin, TANG Zhouxiang, LI Miao, YUAN Xingzhong

Rocky desertification poses a severe threat to ecosystem function in karst regions of southern China. This study, conducted in Jianghua Yao Autonomous County, Hunan Province, investigated the adaptive responses of Paulownia fortunei to rocky desertification habitats and its subsequent effects on soil properties. Leaf structural and physiological parameters were measured, alongside soil physicochemical properties. Results demonstrated that P. fortunei enhanced its adaptability through increased leaf thickness (upper epidermis +50%, total +27.38%), palisade tissue thickness (+22.45%), elevated chlorophyll a (+3.55 mg·g−1) and chlorophyll b (+1.39 mg·g−1) contents, and upregulated activities of superoxide dismutase, catalase, and peroxidase. Planting P. fortunei significantly improved soil structure and fertility: soil bulk density decreased by 0.57 g·cm−3, total porosity increased by 2.41% (0–5 cm) and 3.35% (5–10 cm), field water capacity rose by 18.63% and 18.87%, capillary porosity increased by 11.45% and 14.19%, and soil organic matter content improved from Grade IV to Grade II. These findings indicate a synergistic 'plant adaptation–soil improvement' feedback mechanism, highlighting the potential of P. fortunei for ecological restoration of rocky desertification areas.

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Adaptive Characteristics of Paulownia fortunei to Rocky Desertification Habitats and Its Effects on Soil Properties

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509053• Jan 15, 2026

Comparative Carbon Emission Assessment of Waste Plastic Valorization Pathways

Authors: ZHOU Xiaochao, ZHANG Yuanyuan, XU Jiayu, ZHANG Tingting

The escalating global generation of waste plastics necessitates robust recycling strategies to mitigate environmental impact and advance low-carbon development. This study employs life cycle assessment (LCA) and emission factor methodologies to quantify the carbon footprints of six distinct waste plastic valorization pathways: mechanical recycling, pyrolysis, alcoholysis, co-coking, solid fuel production, and direct incineration. The functional unit is one tonne of waste plastic, with system boundaries encompassing transportation, pretreatment, and resource utilization. The model accounts for indirect emissions from energy consumption, direct emissions from plastic decomposition, and carbon offsets from material or energy recovery. Results indicate that pyrolysis yields the highest carbon offset of approximately -3,024 kgCO2e per tonne, while mechanical recycling achieves an 88% material recovery rate and a net carbon offset of -991.4 kgCO2e. Net carbon emissions per tonne of waste plastic rank as follows: direct incineration (1,104 kgCO2e) > co-coking (185.8 kgCO2e) > solid fuel (115.4 kgCO2e) > alcoholysis (-259.5 kgCO2e) > mechanical recycling (-991.4 kgCO2e) > pyrolysis (-2,592 kgCO2e). These findings demonstrate that pyrolysis offers superior carbon reduction benefits compared to incineration, exhibiting a net-negative carbon footprint across its life cycle. The study provides a scientific basis for selecting low-carbon waste plastic valorization routes and informs carbon trading and emission reduction strategies in the solid waste sector.

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Comparative Carbon Emission Assessment of Waste Plastic Valorization Pathways

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202510084• Jan 15, 2026

Multi-stage thermally assisted alkali activation for simultaneous self-solidification of multiple heavy metals in lithium slag

Authors: JI Zehua, ZHU Zheng, ZHAO Jian, WANG Dianchang, CHEN Yasong, ZHAO Yunpeng

The rapid expansion of lithium battery industries has elevated lithium resources to strategic importance, yet lithium extraction generates 8–10 tons of slag per ton of lithium salt, with complex heavy metal content and high leaching risks. This study improves conventional alkali activation by employing a composite activator and multi-stage thermal assistance to achieve self-solidification of lithium slag, simultaneously immobilizing multiple heavy metals while producing high-strength materials. Under full slag conditions, the mechanical strength of solidified materials ranged from 3.48 to 8.25 MPa; after optimization, strength increased by 137.07%. Average immobilization rates for various heavy metals rose from 97.26% to 99.77%. In simulated acidic, alkaline, neutral, high-salt, acid rain, and leachate environments, efficient immobilization was maintained, with leachate concentrations below regulatory limits. The improved activator and thermal process reduced structural defects, promoted formation of the key Si-O-Al framework, and ensured structural integrity, enhancing both mechanical strength and heavy metal immobilization. The cost of slag solidification was approximately 185–200 CNY per ton, significantly lower than conventional methods, with low energy consumption, no high-temperature calcination, and reduced equipment and reagent requirements, supporting scalability.

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Multi-stage thermally assisted alkali activation for simultaneous self-solidification of multiple heavy metals in lithium slag

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509080• Jan 15, 2026

Catalytic Pyrolysis of LDPE over Low-Cost Metal-Modified ZSM-5 Zeolites: Performance and Product Distribution

Authors: SHAO Pengfei, LIU Lijuan, YANG Ren, ZHOU Chuanbin

Plastic pollution poses a global environmental challenge, and developing efficient, low-cost pyrolysis catalysts is crucial for resource recovery from plastic waste. This study investigates ex-situ catalytic pyrolysis of low-density polyethylene (LDPE) over ZSM-5 (Si/Al = 25) modified with Zn and Fe at loadings of 5% and 10% via impregnation. Catalysts were characterized by XRD, FT-IR, XPS, SEM, TEM, and BET. TGA was used to assess thermal behavior, and catalytic pyrolysis experiments were conducted in a tube furnace at 450 °C, with product analysis by GC-MS. Results show that metal incorporation preserved the ZSM-5 framework while modifying acid site distribution and surface morphology, enhancing cracking and dehydrogenation. All modified catalysts increased light gasoline-range hydrocarbon yield and reduced heavy fractions compared to non-catalytic runs. Among them, 10% Zn/ZSM-5 exhibited the best performance, boosting light gasoline hydrocarbons to 74.77%, approximately three times that of the non-catalytic case, significantly improving oil quality. This study demonstrates the potential of low-cost metal-modified zeolites for efficient and economical plastic waste pyrolysis.

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Catalytic Pyrolysis of LDPE over Low-Cost Metal-Modified ZSM-5 Zeolites: Performance and Product Distribution

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202511090• Jan 15, 2026

Preparation and Performance of Piezoelectric Hydrogels for Accelerating Wound Healing in Damaged Plants

Authors: YANG Longqi, LIAO Qianyi, ZHANG Yong, LI Jinghan, YANG Haitao, LI Yong

In ecological restoration projects such as wetland reconstruction and mine reclamation, seedling transplantation or mechanical damage often leads to slow healing, reducing survival rates and weakening carbon sequestration and soil-water conservation functions. To address secondary pollution from traditional chemical remediation, this study developed a self-powered piezoelectric hydrogel for green electrical stimulation of plant wounds. The hydrogel, based on polyacrylamide/polyethylene glycol (PAM/PEG) with CaCl2, formed a microporous, locally ordered piezoionic network. Characterization included microstructure, piezoionic response, and water retention. At 30 °C and 55% relative humidity, the hydrogel retained about 70% mass after 80 h of continuous water loss. Under simulated environmental mechanical forces, the hydrogel generated a peak voltage of approximately 6 mV. In tomato seedling stem models, wound callus area ratios reached approximately 49.50%, 64.87%, and 86.13% at 3, 5, and 10 days, respectively, when the hydrogel was attached and driven by environmental forces. The PAM/PEG/CaCl2 hydrogel efficiently converts environmental mechanical energy into mild electrical signals, promoting plant wound healing, reducing exogenous chemical use, and offering a low-carbon, environmentally friendly material pathway for ecological restoration and urban green space management.

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Preparation and Performance of Piezoelectric Hydrogels for Accelerating Wound Healing in Damaged Plants

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509095• Jan 15, 2026

Mechanistic Insights into Biochar@PVA-SA Composite Fillers for Enhanced Biopurification of Isohexane in Biotrickling Filters

Authors: QU Miaomiao, ZHENG Yi, ZHOU Renlei, LUO Qiwen, FENG Yuqi, CHENG Zhuowei, SHI Yun, WANG Wenjun, YOU Juping, CHEN Jianmeng

Biotrickling filtration (BTF) is a promising technology for treating volatile organic compounds (VOCs), but its application to hydrophobic alkanes like isohexane is hindered by mass transfer limitations, low degradation efficiency, and high operational costs. To address these bottlenecks, this study developed composite fillers by incorporating biochars derived from coffee grounds (CG), coconut shells (CS), corn cobs (CC), and activated carbon (AC) into a polyvinyl alcohol-sodium alginate (PVA-SA) hydrogel matrix. The fillers were systematically characterized for water retention, pore structure, surface functional groups, crystalline phase, and acid-base resistance. Adsorption capacity, biofilm formation, and isohexane degradation were evaluated using the strain Rhodococcus ruber ZYH-ZY. Among the composites, CG@PVA-SA exhibited superior performance: water retention of 358 mg·g−1 (vs. 280 mg·g−1 for control), enhanced mesoporosity (specific surface area 4.77 m2·g−1, pore volume 11.46 cm3·kg−1, 10–30% higher than control), and robust acid-base stability (mass loss 21.37% at pH 2 and 31.98% at pH 10). Its saturated adsorption capacity reached 201.02 mg·kg−1 (vs. 114.24 mg·kg−1 for control), and it promoted bacterial colonization with a survival rate of 79.0% (vs. 37.2% for control). Static degradation tests showed 96.59% removal of 10 μL isohexane within 24 h. The abundant polar functional groups and suitable mesoporous structure of coffee ground biochar synergized with the PVA-SA matrix, enhancing water retention, mass transfer, and microbial colonization, thereby significantly improving isohexane purification. CG@PVA-SA is an ideal filler for BTF treatment of alkane VOCs, offering a cost-effective and efficient solution for industrial VOC control.

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Mechanistic Insights into Biochar@PVA-SA Composite Fillers for Enhanced Biopurification of Isohexane in Biotrickling Filters

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509001• Jan 15, 2026

Mechanisms and Pilot-Scale Validation of Iron-Loaded Biochar-Based Tidal Flow Constructed Wetlands for Enhanced Deep Nitrogen Removal from Wastewater Treatment Plant Effluent

Authors: HU Anqi, MA Jingsheng, JIANG Yongcan, LIU Guanglong

To address low nitrogen removal efficiency in wastewater treatment plant (WWTP) effluent due to insufficient carbon sources and weak reoxygenation in conventional constructed wetlands (CWs), a tidal flow-subsurface flow integrated CW using iron-loaded biochar (BC-TF) as substrate was developed, with zeolite-based CW as control. Simulated wastewater experiments, water quality monitoring, nitrification/denitrification intensity assays, and high-throughput sequencing were employed. Results showed that tidal flow operation significantly enhanced removal of total nitrogen (TN) and ammonia nitrogen (NH4+-N), and increased nitrification intensity. Addition of iron-loaded biochar significantly improved TN and nitrate nitrogen (NO3−-N) removal, with BC-TF achieving an average TN removal of 86.03%, significantly higher than other groups (P<0.001). Microbial analysis revealed Proteobacteria, Actinobacteria, and Bacteroidetes as key phyla; iron-loaded biochar increased microbial abundance and diversity in tidal flow wetlands, while tidal flow alone reduced bacterial diversity. Pilot-scale experiments confirmed that tidal flow increased dissolved oxygen and nitrogen removal. This study is the first to combine iron-loaded biochar with tidal flow-subsurface flow CWs, systematically revealing the synergistic nitrogen removal mechanism of 'iron-loaded biochar-tidal flow-microorganisms', clarifying the role of iron-nitrogen coupling, and validating engineering applicability via pilot tests. The combination enhances reoxygenation, supplements carbon sources, and optimizes microbial community structure, effectively improving deep nitrogen purification of WWTP effluent, providing technical reference for tailwater treatment.

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Mechanisms and Pilot-Scale Validation of Iron-Loaded Biochar-Based Tidal Flow Constructed Wetlands for Enhanced Deep Nitrogen Removal from Wastewater Treatment Plant Effluent

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202510018• Jan 15, 2026

Assessment Methodology and Application for Stabilization Process of Aged Municipal Solid Waste Landfills

Authors: LIU Xin, LIANG Jianing, ZHANG Ya, LONG Tao, BAI Hao, YUE Dongbei

Scientific assessment and prediction of the stabilization process in aged municipal solid waste (MSW) landfills are critical for reliable risk evaluation and remediation decision-making. Existing methods often fail under data-scarce conditions and lack temporal predictive capability. This study establishes a 'spatial characterization–temporal prediction' framework to address these gaps. The methodology integrates grid-based sampling, laboratory analysis of biological stability indicators (AT4), and LandGEM model simulations to assess current stabilization states and predict completion timelines. Applied to a landfill in southwest China, results reveal significant spatial heterogeneity in waste stabilization, strongly correlated with waste age and influenced by leachate recirculation of membrane concentrate. None of the landfill zones had reached full stabilization; predicted times to completion were: Zone D (17 years), Zone C (13 years), Zone B (8 years), and Zone A (1 year). Based on these findings, a systematic management strategy is proposed, including zoned gradient management, targeted control of lag zones, and dynamic planning. This study provides a theoretical basis for site-specific management and serves as a reference for similar landfills.

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Assessment Methodology and Application for Stabilization Process of Aged Municipal Solid Waste Landfills

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202506080• Jan 15, 2026

Performance and Mechanism of MnO2/γ-Al2O3 for Gaseous Thallium Capture from Cement Kiln Flue Gas

Authors: XING Jiaying, WANG Jiawang, WANG Chunbo, CHEN Jianjun, LI Junhua

Thallium (Tl) is a highly toxic trace heavy metal, posing severe risks to human health and the environment. Cement kilns are significant sources of gaseous Tl emissions, with concentrations up to 25 μg·m−3, which can poison SCR catalysts and cause environmental contamination. This study developed MnO2/γ-Al2O3 adsorbents via wet impregnation with varying Mn loadings (0–15 wt%) to capture gaseous TlCl. Fixed-bed adsorption experiments at 300 °C with 20% O2 revealed that capture capacity initially increased with Mn loading, peaking at 10 wt% MnO2 (10MnO2/γ-Al2O3), then declined at 15 wt%. Characterization (XRD, O2-TPD, H2-TPR) indicated that Mn species enhanced redox properties, oxidizing Tl+ to Tl3+ and immobilizing it on the surface. DFT calculations showed that TlCl forms stronger Al–Cl and Mn–Cl bonds on MnO2/γ-Al2O3 than on γ-Al2O3, with higher adsorption energy and greater charge transfer, corroborating experimental results. The optimal adsorbent, 10MnO2/γ-Al2O3, demonstrates superior Tl capture performance, offering a promising upstream solution for protecting SCR catalysts and reducing atmospheric Tl emissions from cement kilns.

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Performance and Mechanism of MnO2/γ-Al2O3 for Gaseous Thallium Capture from Cement Kiln Flue Gas

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202510004• Jan 15, 2026

Quantitative Evaluation and Coupling Analysis of Purging Performance in Regenerative Thermal Oxidizers Based on CFD Simulation

Authors: CHEN Hongrui, LU Zhaoyang, QU Xiaolei, LI Ming, XU Zunzhu, CHEN Weijie, WEI Ziqiang

Ammonium salt crystallization-induced blockage of the regenerative heat exchanger in regenerative thermal oxidizers (RTOs) remains a critical operational challenge, particularly in pharmaceutical applications where NH4Cl constitutes up to 70% of the fouling deposits. This study employs computational fluid dynamics (CFD) to systematically simulate six purging configurations, varying injection angle and pipe arrangement, and quantifies purging effectiveness via a novel evaluation method based on characteristic observation planes. Using the Realizable k-ε turbulence model coupled with a porous media model, we analyze the velocity distribution and low-velocity failure zones at the gas chamber–regenerator interface. Results demonstrate that a single-pipe 45° oblique injection achieves the highest effective purging area of 57.6%, a 35.7% improvement over conventional horizontal purging. Increasing pipe diameter significantly enhances flow uniformity, yielding an efficiency gain of approximately 40%, outperforming mere increases in gas velocity. A synergistic optimization strategy is proposed, prioritizing high-performance purging structures with coordinated parameter tuning. The recommended configuration—single-pipe 45° injection, 280 mm pipe diameter, and 14 m·s−1 gas velocity—achieves 88.2% purging efficiency without additional fan power, representing a 45.6% improvement over conventional modes. These findings provide a theoretical basis and engineering solution for RTO purging system design and operational optimization.

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Quantitative Evaluation and Coupling Analysis of Purging Performance in Regenerative Thermal Oxidizers Based on CFD Simulation

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202509072• Jan 15, 2026

Precision Source Parameter Inversion for Typical Air Pollutant Emissions at Microscale: An Integrated PSO-NM Algorithm and Gaussian Dispersion Model Approach

Authors: CUI Jixian, BAI Zishuo, SUN Lei, HONG Ningning, PENG Shitao, YE Yin, ZHANG Guangming

Accurate identification of pollutant emission source parameters is critical for effective pollution response. This study evaluates the performance of genetic algorithm (GA), Nelder-Mead simplex (NM), particle swarm optimization (PSO), and their coupled variants on multi-dimensional, multi-extremum benchmark functions, and develops a source parameter inversion technique integrating PSO-NM with a Gaussian dispersion model. Validation via sulfur hexafluoride (SF6) single-point and multi-point release experiments demonstrates that PSO-NM achieves mean values closest to theoretical optima on Shubert, Hartmann, and Shekel functions, with superior stability and precision. In single-point source experiments, the relative deviation of source strength (Q) inversion ranges from -27.1% to 38.5%, with positional errors below 10 m, indicating robust convergence and repeatability. Multi-point source inversion exhibits stability across two scenarios but with reduced accuracy compared to single-point cases. When source strength is unknown, inversion accuracy for low-release sources (relative deviation 37.3%-70.4%) surpasses that for high-release sources; when position is unknown, positional deviations generally remain below 50 m, with low-release sources yielding better x0 deviations (-1.6 to 8.2 m) but slightly worse y0, z0, and distance parameters. Inversion errors primarily stem from meteorological non-stationarity, inter-source interference, algorithmic local optima, low-concentration measurement noise, and model assumptions. Future improvements may incorporate real-time meteorological correction and source-specific constraints to enhance accuracy and robustness in complex scenarios. The findings provide technical support for precise source tracing, monitoring, and refined management of pollutant emissions at microscale in industrial parks and enterprises.

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Precision Source Parameter Inversion for Typical Air Pollutant Emissions at Microscale: An Integrated PSO-NM Algorithm and Gaussian Dispersion Model Approach

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202510041• Jan 15, 2026

Ten-Thousand-Ton Scale Engineering Practice of Retrofitting a UASB Reactor into an Aerobic Granular Sludge Process

Authors: WANG Xianglian, MA Lin, JIA Chunfang, CHEN Kai, LIN Sijie, XU Wei, WU Weijun, LYU Jianhao, YANG Caoling, HU Qing

This study presents a full-scale engineering practice of retrofitting an idle upflow anaerobic sludge blanket (UASB) reactor into an aerobic granular sludge (AGS) system for treating low-strength municipal wastewater. The design capacity was 20,000 m3/d (maximum 24,000 m3/d), achieving separate treatment of industrial and domestic wastewater to reduce operational costs. Systematic analysis covered hydraulic capacity enhancement, effluent quality, pollutant removal efficiencies, sludge granulation progress, and operational costs. Results showed rapid start-up: the system reached 75% of design capacity by day 10 and 90% by day 26. During a 4-month operation, average removal efficiencies for COD, NH4+-N, TN, and SS were 83.2%, 97.0%, 75.9%, and 94.4%, respectively, even under low influent BOD5/TN ratios (typically below 4). Granulation progressed quickly: by day 44, average particle size was 2.6 times that of the inoculum and over 4 times that of flocs, with granules (>200 μm) accounting for 17.3%; by day 110, these values increased to 3.2 times and 5 times, with granule proportion reaching 33.4%. Compared to the previous year (June–August), the AGS process reduced electricity consumption, chemical consumption, and sludge production by 77.3%, 25.4%, and 30.4%, respectively, while saving 65.6% of footprint. This ten-thousand-ton case provides a practical basis for AGS technology application in China.

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Ten-Thousand-Ton Scale Engineering Practice of Retrofitting a UASB Reactor into an Aerobic Granular Sludge Process

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Original ResearchVol. 20, Issue 5 • pp. 100-112DOI: 10.12030/j.cjee.202508101• Jan 15, 2026

Desulfurization of Lead-Zinc Molten Slag and Synergistic Oxidation of NOx with NaClO2

Authors: LIU Jiawen, ZHU Han, SUN Lina, LI Kai, SUN Xin, MA Yixing

The emission of sulfur dioxide (SO2) and nitrogen oxides (NOx) from fossil fuel combustion and metal smelting industries poses severe risks to environmental and human health. This study utilized depleted lead-zinc molten slag as a desulfurizer for wet flue gas desulfurization, and the resulting desulfurization slurry was further employed for NOx removal, achieving resource utilization. The desulfurization efficiency of the slag was determined, and NaClO2 was identified as the most effective oxidant when combined with the slag slurry for NOx removal. The effects of NaClO2 concentration, reaction temperature, flue gas flow rate, oxygen concentration, NOx concentration, and pH on removal efficiency were investigated. Optimal conditions were found at NaClO2 concentration of 2.5 mmol·L−1, temperature 45 °C, flue gas flow 200 mL·min−1, O2 volume fraction 10%, NOx volume fraction 0.03%, and pH 6, achieving a NOx removal efficiency of 97.24%. Metal ion experiments revealed that Fe3+, Zn2+, Mn2+, and K+ exhibited synergistic effects with NaClO2, with Fe3+ showing the most significant enhancement. Fe3+ promoted the decomposition of NaClO2 to generate stronger oxidants such as ClO2, thereby enhancing NOx oxidation and absorption. This approach offers a cost-effective and environmentally friendly alternative to traditional selective catalytic reduction, avoiding ammonia slip and secondary pollution.

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Desulfurization of Lead-Zinc Molten Slag and Synergistic Oxidation of NOx with NaClO2

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202511047• Jan 15, 2026

Carbon Emission Accounting Method for Ultra-High Voltage Transmission Line Construction Considering Carbon Intensity and Activity Data Uncertainty

Authors: ZHANG Yujiao, LI Zhiqi, YANG Yanhui, HAN Yang, HUANG Xiongfeng, JU (Corresponding author: HUANG Xiongfeng)

Ultra-high voltage (UHV) transmission lines are critical infrastructure for China's energy strategy. Compared with conventional voltage lines, UHV lines exhibit nonlinear growth in resource and capital consumption, complex supply chains, and strong spatiotemporal heterogeneity in carbon emission factors, resulting in substantial and uncertain construction-phase emissions. Accurate accounting is essential for achieving carbon peaking and carbon neutrality goals in the power sector. To address issues of ambiguous system boundaries, weak characterization of input parameter uncertainty, and poor cross-year applicability of input-output carbon intensities, this study defines the accounting boundary using budget quotas and develops a hybrid life cycle assessment (HLCA) model. For easily traceable emission sources, process-based LCA (PLCA) is applied, with uncertainty analysis via distribution fitting and Monte Carlo simulation. For difficult-to-trace sources, input-output LCA (IO-LCA) is used with carbon intensity correction. A case study of a ±800 kV transmission line yields a construction-phase carbon emission intensity of 1,858.91 t·km⁻¹ (CO₂ equivalent), with a 95% confidence interval of [1,379.73, 2,486.45] t·km⁻¹. Sobol global sensitivity analysis identifies key emission reduction pathways. The method's validity is confirmed by comparison with existing studies, providing quantitative support for low-carbon design, construction optimization, and carbon auditing of UHV projects.

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Carbon Emission Accounting Method for Ultra-High Voltage Transmission Line Construction Considering Carbon Intensity and Activity Data Uncertainty

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202502081• Jan 15, 2026

Spatiotemporal Variation Characteristics of Coal Dust Pollution in the Baorixile Mining Area

Authors: GAO Sihua, HUO Jiangrun, LI Jing, ZHANG Jinpeng, FU Xiao, WANG Yujue, WANG Kewen

Coal dust from open-pit mining severely impacts the mining area and surrounding environment, exhibiting significant dynamic changes. However, quantitative assessments of the pollution extent and multi-timescale evolution remain insufficient. Based on the Google Earth Engine platform and Landsat TM/ETM+/OLI/OLI-2 and Sentinel-2 MSI imagery from 2001 to 2024, we retrieved the enhanced coal dust index (ECDI) and coal dust pollution levels. Combined with the mine lifecycle stages, we revealed the temporal and spatial variations of coal dust in the Baorixile mining area. Annual and monthly remote sensing retrievals were stacked to construct multi-year and intra-annual dust impact frequency (DIF) indicators, precisely quantifying the spatial extent and frequency of coal dust pollution. Results show that from 2001 to 2024, the interannual coal dust pollution experienced three stages: fluctuating increase, significant decrease, and stabilization. The average pollution degree peaked at 0.41 in 2010 and remained between 0.18 and 0.22 from 2016 to 2024. The spatial pattern improved, converging from widespread diffusion to the open-pit and bare coal accumulation areas. From 2019 to 2023, intra-annual pollution increased then decreased, with summer most severe, followed by autumn, spring, and winter. Based on annual retrievals, 6 periods of multi-year DIF (2001-2024) were generated at 4-year intervals. The maximum impact range (DIF≥1) first expanded then contracted significantly; the perennial impact area (DIF=4) shifted from the southeast to the central-western open-pit, indicating a notable migration of dust disturbance gravity and effective control. Based on monthly retrievals, 6 periods of intra-annual DIF (2019-2024) were generated at 12-month intervals. The intra-annual DIF showed a gradient decreasing from the core operation area to the periphery. High-frequency zones (DIF≥9) were stably concentrated in the open-pit. The affected area fluctuated downward from 88.14 km² in 2019 to 72.84 km² in 2024. This study provides theoretical and data support for scientifically understanding and monitoring the ecological status of mining areas and formulating dust suppression measures.

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Spatiotemporal Variation Characteristics of Coal Dust Pollution in the Baorixile Mining Area

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202510060• Jan 15, 2026

Removal Efficiency of Emerging Contaminants in Wastewater Treatment Plant Effluent by Gravel-Based Constructed Wetlands

Authors: HUANG Yangrui, CHEN Yasong, ZHAO Yunpeng, ZHAO Jian, JI Zehua, LIU Huijuan

Wastewater treatment plant (WWTP) effluent is a significant pathway for emerging contaminants (ECs) to enter natural water bodies. This study investigated the removal of ECs by two field-scale gravel-based constructed wetlands: a horizontal subsurface flow constructed wetland (QL-CW) and a surface flow constructed wetland (BL-CW), both treating actual WWTP effluent. The influence of operation mode and wetland plant type on EC removal was examined. Using liquid chromatography-mass spectrometry, principal component analysis, and ecological risk assessment, the removal efficiencies and mechanisms for various ECs were explored. In QL-CW, biodegradation was more pronounced, particularly via ammonia-oxidizing bacteria co-metabolism, favoring ECs with benzyl, secondary amine, secondary amide, tertiary amide, halogenated, and carboxyl functional groups. In BL-CW, electrostatic attraction and hydrophobic interactions were more significant, with plant and root-microorganism uptake and adsorption playing key roles. Surface flow mode achieved significantly higher removal of antibiotics (45.3% vs. 34.1%) compared to horizontal subsurface flow, while no significant differences were observed for non-antibiotic pharmaceuticals (66.6% vs. 64.4%) and pesticides (49.8% vs. 34.2%). Planting Cyperus alternifolius (windmill grass) was more beneficial for antibiotic removal (43.6% vs. 30.1%) than planting Ipomoea aquatica (water spinach). The wetlands effectively reduced the ecological risks of most ECs to marginal levels. This study provides insights into the deep treatment of ECs in WWTP effluent by constructed wetlands.

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Removal Efficiency of Emerging Contaminants in Wastewater Treatment Plant Effluent by Gravel-Based Constructed Wetlands

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202511003• Jan 15, 2026

Research Progress on Combined Stress Effects of Secondary Water Pollution from Tailings Dam Leakage on Aquatic Organisms

Authors: WANG Yuchen, XU Li, FENG Yanhui, ZHU Jialin, CAI Qijia, YAO Ling'ai, LIANG Rongchang, WANG Yuqi, XU Xuefeng, MA Qianli

Tailings dam leakage can cause secondary sudden water pollution events, imposing severe combined stress of high turbidity and heavy metal contamination on natural water bodies within a short period, threatening aquatic ecological security. Existing studies have systematically revealed the pollution characteristics and biological effects of such events, which are fundamentally distinct from natural high-turbidity water and industrial wastewater leakage. Compared with natural high-turbidity water, tailings leakage inputs finer particles with higher specific surface area, leading to more intense and prolonged turbidity stress. Meanwhile, heavy metals in tailings are more enriched than natural sediments, with higher proportions of active forms and bioavailability, causing significant bioaccumulation and toxic effects, and long-term decline in benthic community species richness. Compared with industrial wastewater leakage, tailings leakage simultaneously releases high concentrations of fine suspended solids and multiple heavy metals, forming a unique 'physical-chemical' combined stress. This synergistic effect amplifies biological toxicity through multiple pathways such as mechanical damage, light limitation, and oxidative stress, resulting in severe and often irreversible ecological damage, such as impaired fish swimming behavior and collapse of benthic community structure. Analyzing the long-term impacts of tailings leakage on aquatic ecosystems from the perspective of combined stress is helpful for providing scientific basis for emergency response and medium-to-long-term ecological risk prevention of related sudden water pollution events.

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Research Progress on Combined Stress Effects of Secondary Water Pollution from Tailings Dam Leakage on Aquatic Organisms

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202511087• Jan 15, 2026

Source Apportionment and Driving Factors of Heavy Metal Pollution in Paddy Soils Around a Mining Area Using PMF and XGBoost-SHAP Models

Authors: HU Jiaxue, LI Pei, SONG Shihong, WANG Xueping

Identifying the sources and driving factors of heavy metals (HMs) in paddy soils around mining areas is crucial for safeguarding regional agricultural production and food security. This study focused on paddy soils near a mining area in southern Jiangxi Province, integrating Spearman correlation analysis, positive matrix factorization (PMF), and extreme gradient boosting (XGBoost) coupled with SHapley Additive exPlanations (SHAP) to quantitatively apportion potential ecological risks, pollution sources, and driving factors. Results showed that mean concentrations of Pb, Ni, and Cu exceeded the soil background values of Jiangxi Province, except for Cr. The mean comprehensive potential ecological risk index (RI) was 17.4, with 25.7% of sampling sites exhibiting moderate risk, and Ni being the primary ecological risk factor. Source apportionment identified three main sources: natural background (51.1%), industrial and mining activities (26.6%), and a mixed source of agricultural activities and traffic emissions (22.3%). Spatial variation of Cr, Cu, and Ni was predominantly governed by soil physicochemical properties (Fe and P contents), whereas Pb distribution was significantly influenced by industrial and mining activities. The combination of PMF and XGBoost-SHAP effectively delineated sources and driving factors, providing a scientific basis for targeted soil management and pollution control in mining-affected agricultural regions.

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Source Apportionment and Driving Factors of Heavy Metal Pollution in Paddy Soils Around a Mining Area Using PMF and XGBoost-SHAP Models

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202505106• Jan 15, 2026

Effects of Different Fertilization Treatments on Soil Nutrient Availability and Microbial Response Mechanisms in the Baiyinhua Open-Pit Mining Area

Authors: SUN Guohao, LI Jingguo, QU Laiye, GOU Tienan, JIA Hongjun, YANG Ziyu, ZHANG Naili

Open-pit coal mining causes severe soil nutrient depletion, limiting vegetation restoration. This study, conducted in the Baiyinhua No.2 mining area (Inner Mongolia), evaluated the effects of different fertilization strategies on soil nitrogen (N) and phosphorus (P) availability and microbial community responses. A field experiment was established in May 2023 with five treatments: low (L), medium (M), and high (H) phosphorus inorganic fertilizers, green manure (GM), and a microbial fertilizer (MF) containing nitrogen-fixing and rhizobia bacteria, compared to a control (CK). Results showed that MF significantly increased total carbon (TC) from 8.47 to 10.17 g·kg⁻¹ and total nitrogen (TN) from 0.37 to 0.56 g·kg⁻¹, while H significantly increased available phosphorus (AP) from 9.78 to 26.28 mg·kg⁻¹. Both treatments significantly altered fungal community structure, with increased relative abundances of Gibberella and Alternaria. The study concludes that MF and H improve soil nutrient availability by modulating fungal communities, with MF offering a sustainable biological approach for mine reclamation. These findings provide targeted fertilization strategies for restoring degraded mining soils and advancing green mining practices.

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Effects of Different Fertilization Treatments on Soil Nutrient Availability and Microbial Response Mechanisms in the Baiyinhua Open-Pit Mining Area

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202509036• Jan 15, 2026

Chitosan Coupled with Electroflotation for Phosphorus Recovery from Eutrophic Taihu Lake Water

Authors: WANG Jiayu, HUANG Siyu, ZHANG Zhenxiu, LIU Guangyao, ZHANG Qingji, ZOU Lei, SHI Wenqing, ZHU Lin

Algal-derived phosphorus (P) constitutes a significant fraction in eutrophic lakes, with particulate phosphorus (PP) serving as both a major internal P reservoir and a potential target for P resource recovery. This study proposed a chitosan-coupled electroflotation (CEF) technology for efficient enrichment and recovery of algal-derived P from high-algal water. Using Taihu Lake algae-laden water as the test medium, the effects of chitosan dosage and voltage on the enrichment of different P fractions were systematically evaluated. Results showed that the optimal P enrichment was achieved at a chitosan dosage of 15 mg·L−1, and higher voltages further enhanced the enrichment efficiency. Under optimal conditions, PP accounted for 83.57% of the enriched P, indicating a strong capability for particulate P capture. The mechanism involved chitosan-induced flocculation via charge neutralization and sweep flocculation, while higher voltages increased the positive charge density of chitosan molecules, enhancing charge neutralization and electroflotation. In P release experiments, open conditions significantly promoted the transformation of PP to dissolved P, whereas closed conditions inhibited this process. Additionally, chitosan's antibacterial action and physical retention effectively limited P release. Compared with conventional metal salt coagulants, this method avoids metal ion residues, offering high environmental safety and providing a green and feasible approach for the harmless disposal and resource utilization of algal-derived P in eutrophic lakes.

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Chitosan Coupled with Electroflotation for Phosphorus Recovery from Eutrophic Taihu Lake Water

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202505104• Jan 15, 2026

Synergistic Remediation of Aged Oil-Contaminated Soil by Plants and Degrading Microbial Consortium

Authors: ZHAO Lei, JI Xuan, YANG Jingfeng, PEI Zixuan, GUAN Shengdi, YU Yan

This study investigated the synergistic remediation of aged oil-contaminated soil collected from an oil well in Yanchang, northern Shaanxi, China, with an initial total petroleum hydrocarbon (TPH) concentration of 17.1 g·kg⁻¹, exceeding the second-class land use screening value (4,500 mg·kg⁻¹) by approximately 3.8-fold. Indigenous high-efficiency degrading strains were screened and a microbial consortium was constructed. Pot experiments were conducted to compare the TPH degradation efficiencies and soil property changes under plant, microbial, and combined plant-microbial remediation. The consortium MC-5 (SDB1:SDB2:SDB3:SDB4 = 1:1:0:3) exhibited the highest TPH degradation rate of 83.46% in liquid culture. In soil, combined remediation with ryegrass (Lolium perenne) achieved a TPH degradation rate of 60.93%, significantly higher than the control (CK) by 54.26 percentage points. The consortium also degraded recalcitrant resins and asphaltenes by 49.44%. The microbial consortium played a dominant role, contributing 63%–69% to TPH removal, whereas plant contribution was only 2%–12%, primarily in the later stage. Addition of rhamnolipid biosurfactant enhanced the combined remediation, increasing TPH degradation by 7.05 percentage points compared to non-amended treatments. These findings provide insights into the mechanisms of plant-microbial synergy and offer theoretical and practical guidance for bioremediation of petroleum-contaminated soils.

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Synergistic Remediation of Aged Oil-Contaminated Soil by Plants and Degrading Microbial Consortium

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202505108• Jan 15, 2026

Research Progress and Prospects of Aboveground-Belowground Synergistic Restoration Principles and Technologies for Degraded Ecosystems in Open-Pit Mines in High-Cold Regions

Authors: ZHANG Naili, YU Tongrui, LI Xingxuan, XU Changyou, LIU Yongjie, QU Laiye

Open-pit mining in high-cold regions causes severe ecological degradation, including vegetation loss, soil structure destruction, and frequent freeze-thaw disturbances, complicating ecosystem recovery. This review systematically synthesizes the current status, theories, and key restoration technologies for degraded ecosystems in high-cold mining areas. Comparative analysis with typical high-cold degraded ecosystems worldwide reveals that high-cold mining areas face challenges such as frequent freeze-thaw cycles, hydrological disruption, wind erosion, and difficult vegetation establishment. We propose strengthening aboveground-belowground synergistic restoration: (1) aboveground restoration should focus on screening cold-resistant native plants and optimizing mixed community configurations, combined with plant growth-promoting multi-microbial consortia to facilitate vegetation recovery; (2) belowground restoration should be based on engineering soil profile reconstruction, integrating physical-chemical-biological multi-dimensional remediation techniques to achieve aboveground and belowground community reconstruction and functional recovery; (3) a progressive restoration framework is established, with short-term goals targeting soil stabilization and structure improvement, medium-term goals focusing on constructing multifunctional plant-soil communities, and long-term goals achieving self-sustaining, maintenance-free restored ecosystems. Finally, addressing the unclear mechanisms of aboveground-belowground synergistic interactions and insufficient environmental adaptability of restoration technologies, two prospects are proposed: (1) deepening research on aboveground-belowground synergistic mechanisms to reveal interactions between cold-tolerant microorganisms and plants; (2) advancing the development of characteristic restoration technologies adapted to high-cold environments.

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Research Progress and Prospects of Aboveground-Belowground Synergistic Restoration Principles and Technologies for Degraded Ecosystems in Open-Pit Mines in High-Cold Regions

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202505103• Jan 15, 2026

Drought Resistance Evaluation of Dominant Species in Inner Mongolia Desert Steppe During Seed Germination

Authors: ZHANG Tingting, LI Xin, FEI Xihao, QU Laiye, YU Yan

This study evaluated the drought resistance of seven dominant plant species from the Inner Mongolia desert steppe during seed germination to identify suitable species for ecological restoration of arid mining dumps. Seeds were subjected to soil moisture gradients ranging from 2.56% to 12.77% to simulate drought stress. Germination percentage, growth parameters, germination index, simplified vigor index, and drought resistance index were measured. A multi-dimensional evaluation system was constructed using the membership function method. Results showed that with increasing water stress, germination parameters generally declined nonlinearly. Under severe drought (soil moisture 5.11%), Lolium perenne and Melilotus officinalis exhibited significantly higher germination rates than other species (P<0.05). Comprehensive evaluation ranked drought resistance as: Lolium perenne > Melilotus officinalis > Setaria viridis > Elymus dahuricus > Medicago sativa > Astragalus adsurgens > Artemisia oxycephala. These findings indicate that Lolium perenne, Melilotus officinalis, and Setaria viridis possess strong drought resistance and can serve as pioneer species for vegetation reconstruction in mining areas. Furthermore, a soil moisture content of 5.11% (40% of field capacity) was identified as the lower threshold for seed germination, providing a quantitative basis for water management in arid mining ecological restoration.

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Drought Resistance Evaluation of Dominant Species in Inner Mongolia Desert Steppe During Seed Germination

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202511004• Jan 15, 2026

Diffusion Coefficient and Microbial Community Structure Dynamics During Acclimation of Encapsulated Immobilized Denitrifying Bacteria

Authors: LI Hua, ZHAI Luoluo, DUAN Yafei, DONG Hongbiao, MA Yanwu, ZHANG Jiasong, JU

To address nitrate nitrogen accumulation in aquaculture tailwater, a core-shell encapsulated immobilized denitrifying bacterial capsule containing lychee seed powder and denitrifying activated sludge was developed. The capsule's micro-morphology, bacterial activity recovery, growth, community structure changes, and diffusion coefficient dynamics during acclimation were investigated. The capsule shell exhibited a honeycomb porous structure with an average pore size of (0.25 ± 0.063) μm. Denitrifying bacterial activity recovered rapidly, with nitrate nitrogen removal efficiency stabilizing at 83.61% by day 21. Biomass within the capsules increased progressively, reaching (21.96 ± 0.28) mg·(g-pellet)−1 on day 30. The effective diffusion coefficient decreased with biomass growth, dropping to 0.232 × 10−9 m²·s−1 by day 30. Organic carbon source and encapsulation acclimation environment altered the microbial community structure; after acclimation, dominant genera were Methylobacterium (22.8%), Brevibacillus (18.1%), and Azospirillum (17.3%). Denitrifying bacteria containing nirS- and nirK- genes predominantly belonged to Proteobacteria (>99%). Genera involved in organic carbon metabolism and denitrification, including Bosea, Bradyrhizobium, Rhizobacter, and Alicycliphilus, increased in abundance. The encapsulated denitrifying bacteria exhibited short activity recovery time and excellent denitrification performance, making them suitable for denitrification of aquaculture tailwater or other low C/N ratio wastewater.

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Diffusion Coefficient and Microbial Community Structure Dynamics During Acclimation of Encapsulated Immobilized Denitrifying Bacteria

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202510034• Jan 15, 2026

Chloride-Enhanced Fe(II)/PMS/H2O2 System for Degradation of PBTC and Simultaneous Recovery of Iron Phosphate

Authors: WEN Shuozhao, LIU Xueyu, LI Jiaqian, WU Xiangyang, LING Yu, GUO Zhenjie, LI Guowen, LI Yibing, ZHANG Juanjuan

Phosphonate wastewater, characterized by stable C–P bonds, poses significant environmental risks due to its resistance to degradation and potential to contribute to eutrophication. This study developed a chloride-enhanced Fe(II)/PMS/H2O2 system for the oxidative degradation of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) and simultaneous recovery of phosphorus as iron phosphate (FePO4). Under optimal conditions (0.1 mmol/L PBTC, 1.0 mmol/L Fe(II), 0.5 mmol/L PMS, 0.5 mmol/L H2O2, 10 mmol/L NaCl, initial pH 3.0, 60 min), total phosphorus (TP) removal reached 100%, with phosphorus nearly completely recovered as FePO4 precipitate. Increasing NaCl concentration and temperature enhanced TP removal, while pH significantly influenced removal efficiency and product speciation; acidic conditions (pH < 4.3) favored FePO4 precipitation. Coexisting Ca2+ and Mg2+ had negligible effects, whereas HCO3− and humic acid (HA) inhibited TP removal in a concentration-dependent manner. Radical quenching and electron spin resonance (ESR) analyses identified hydroxyl radicals (•OH), ferryl ion (Fe(IV)=O), sulfate radicals (SO4•−), and chlorine radicals (Cl•) as primary reactive species, with •OH playing a dominant role. Chloride introduction promoted the generation of multiple reactive species, and Cl• and its derivative Cl2•− directly attacked the C–P bond and phosphonate group, facilitating phosphorus release as PO43− and subsequent FePO4 formation. The system's feasibility was validated using actual industrial circulating cooling water. This study provides a novel approach for phosphonate wastewater treatment and phosphorus recovery.

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Chloride-Enhanced Fe(II)/PMS/H2O2 System for Degradation of PBTC and Simultaneous Recovery of Iron Phosphate

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202503016• Jan 15, 2026

Microbial Mechanisms Underlying Soil Nutrient Availability in Vegetation Reconstruction of an Open-Pit Mining Area in Inner Mongolia

Authors: GOU Tienan, SUN Guohao, LI Jingguo, ZHANG Liming, ZENG Lixue, LI Haichao, QU Laiye, ZHANG Naili

Open-pit coal mining severely damages soil and plant community structure and function, causing soil nutrient loss and ecological degradation. Vegetation reconstruction is a key measure for restoring degraded mining ecosystems, with the core challenge being the selection of suitable plant species and optimization of plant configurations. This study focused on the degraded ecosystem of the Baiyinhua open-pit mine in Inner Mongolia, screening native plant species for vegetation reconstruction experiments to investigate early-stage changes in soil nutrient availability and the underlying microbial mechanisms. Results showed that soil physicochemical properties and fungal community diversity exhibited strong adaptability during early reconstruction. However, soil fungal community composition and the relative abundance of saprotrophic fungi differed significantly among plant configurations. Leymus chinensis significantly increased the proportion of soil saprotrophic fungi from 67.28% in the control to 81.63%, while reducing the relative proportion of pathogenic fungi from 15.63% to 4.33%, demonstrating its potential to enhance soil health. Medicago rivularis improved soil microbial community composition and increased soil available phosphorus content, highlighting its capacity as an excellent pioneer species for optimizing soil nutrient availability. Furthermore, mixed sowing of grasses and legumes showed potential to enhance the nitrogen-fixing effect of legumes. Given the significant positive correlation between soil fungal community composition and total nitrogen and available nitrogen, the effects of different plant configurations on soil nutrient availability and biological health likely stem largely from the regulation of soil fungal community composition. In conclusion, achieving the goal of selecting optimal plant configurations still requires long-term continuous observation and analysis, particularly for optimizing configurations between high-quality grasses like Leymus chinensis and legumes.

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Microbial Mechanisms Underlying Soil Nutrient Availability in Vegetation Reconstruction of an Open-Pit Mining Area in Inner Mongolia

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202509055• Jan 15, 2026

Magnetic Field Modulation of Microbial Functional Specialization for Optimizing Environmental Bioprocesses: A Review

Authors: WANG Guoliang, KANG Jiaqi, LI Ruixiang, LI Tian

Microbial communities are the core functional units in environmental biotechnology. Magnetic field technology, as a non-invasive physical enhancement method, has shown application potential in wastewater treatment and waste resource recovery. Traditional ecological theory posits a positive correlation between species diversity and system function/stability. However, magnetic field enhancement often coincides with improved system performance and decreased microbial diversity, indicating a decoupling. This review systematically explains this phenomenon as the result of magnetic field-driven functional specialization of microbial communities. Magnetic fields act on paramagnetic targets in energy metabolism, including iron-sulfur clusters and cytochromes, alter cell surface physicochemical properties, impose oxidative stress, and select strains with high metabolic flexibility, thereby achieving targeted enrichment of key functional groups such as ammonia-oxidizing bacteria and electroactive bacteria within Proteobacteria. Although such functionally specialized communities have reduced species richness, they exhibit higher energy metabolism efficiency, enhanced electron transfer capacity, optimized interspecies cooperation networks, and strengthened system robustness. These advantages collectively support efficient and stable macroscopic bioprocess performance. This study also discusses potential limitations regarding ecosystem resilience and scenario dependence, and envisions future directions such as quantitative modeling and synergy with magnetic materials to advance magnetic field technology from empirical application to rational design.

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Magnetic Field Modulation of Microbial Functional Specialization for Optimizing Environmental Bioprocesses: A Review

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202509031• Jan 15, 2026

Carbon Footprint and Environmental Benefits of Waste Television Dismantling and Recycling: A Life Cycle Assessment Study

Authors: LI Huan, XU Zi-yin, JIANG Yuan-yuan, WU Tian, CHEN Meng-jun

This study establishes a carbon footprint calculation method and an environmental benefit assessment model for the dismantling process of waste televisions (TVs) based on life cycle assessment (LCA). Activity data on energy consumption and material flows were collected from typical treatment enterprises via field investigation. The ReCiPe 2016 model was applied to quantify midpoint and endpoint environmental impacts. Results show that the dismantling and recycling process yields net environmental benefits in most impact categories. At the midpoint level, significant reductions were observed in fossil resource scarcity (−26,494.23 kg oil eq), freshwater ecotoxicity (−2.21×10^4 kg 1,4-DCB), and greenhouse gas emissions (−956.53 kg CO2 eq). At the endpoint level, reductions in human health damage (−1.59×10^4 DALY), ecosystem damage (−2.35×10^4 species·yr), and resource depletion costs (−4.22×10^4 USD) were achieved. Carbon footprint analysis indicates that the carbon footprint per TV ranges from 0.231 to 0.247 kg CO2 eq per unit, with electricity consumption as the dominant emission source. Sensitivity analysis reveals that electricity consumption significantly influences the carbon footprint. Finally, emission reduction recommendations are proposed from aspects of equipment upgrade and energy management, providing theoretical basis and practical guidance for low-carbon treatment of electronic waste.

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Carbon Footprint and Environmental Benefits of Waste Television Dismantling and Recycling: A Life Cycle Assessment Study

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202511057• Jan 15, 2026

Effects of Field Application of Sewage Sludge Aerobic Fermentation Products on Antibiotic Resistance Gene Prevalence in Pakchoi (Brassica chinensis L.)

Authors: MA Shijin, HE Dahai, WANG Bin, HE Ruoxue, ZHOU Litao, LI Jiang, JU, HAI Lipeng

To investigate the effects of applying sewage sludge aerobic fermentation products on antibiotic resistance genes (ARGs) in the rhizosphere soil and phyllosphere of pakchoi (Brassica chinensis L.), field experiments were conducted with three treatments: sludge product (sludge group), chemical fertilizer (fertilizer group), and no fertilizer (control). Antibiotic residues, abundances of ARGs and mobile genetic elements (MGEs) were measured in rhizosphere soil and phyllosphere, and microbial community composition and virulence factor (VF) contributions were annotated via metagenomics. Results showed that antibiotic concentrations in rhizosphere soil were generally higher than in phyllosphere. Compared with control, sludge application increased soil antibiotic content by 12.70%, whereas fertilizer increased it by only ~3%, indicating a more significant exogenous input from sludge. At the resistance level, total ARG abundances in rhizosphere soil and phyllosphere of the sludge group increased by 25.47% and 73.08%, respectively, relative to control, with concurrent increases in beta-lactam resistance genes and MGEs such as integron intI1. Sludge application may enhance integron-mediated gene capture and horizontal transfer potential, driving resistance risk accumulation in both phyllosphere and rhizosphere soil. Conversely, fertilizer application reduced ARG abundances by 53.40% in rhizosphere soil and 13.50% in phyllosphere compared with control, consistent with decreased microbial community abundance and diversity, suggesting that reduction of host bacteria and dissemination vectors was a key reason. In community structure, Proteobacteria dominated the phyllosphere, while Chloroflexi dominated rhizosphere soil. Correlation networks identified Sphaerobacter thermophilus and Aggregatilinea lenta positively correlated with multiple ARGs (r≈0.95–1.00), whereas Solirubrobacter sp. CPCC_204708 was negatively correlated (r≈−0.91). Virulence factor contributions followed trends similar to ARGs. Sludge fermentation products simultaneously increased ARG prevalence and related risk indicators in both rhizosphere soil and phyllosphere of pakchoi, providing a reference for risk identification and safe application of sludge fermentation products in agriculture.

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Effects of Field Application of Sewage Sludge Aerobic Fermentation Products on Antibiotic Resistance Gene Prevalence in Pakchoi (Brassica chinensis L.)

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202510029• Jan 15, 2026

Optimization of Thermal Hydrolysis Pretreatment of Corn Straw for Enhanced Methane Production

Authors: LI Zhibo, XIE Juan, HAN Yongchen, LI Su, WANG Xiaochang, LI Yuyou, CHEN Rong, XING Baoshan

Low hydrolysis efficiency is a core bottleneck in anaerobic digestion (AD) of lignocellulosic agricultural residues, limiting methane production and resource utilization. This study optimized thermal hydrolysis pretreatment (THP) of corn straw (CS) using response surface methodology (RSM) to enhance methane yield. The optimal conditions were determined as solid-to-liquid ratio of 51.0–57.5 mg·mL−1, pretreatment time of 74–81 min, and temperature of 182.5–197.5 °C. Under the optimal combination (52.3 mg·mL−1, 78.4 min, 191 °C), cumulative methane yield increased from 218.0 to 362.9 mL·g−1 VS, a 66.7% improvement over untreated CS. Characterization via XRD, FTIR, and SEM revealed that THP disrupted the lignocellulosic structure, reducing lignin content from 21.5% to 8.3% and crystallinity index (CrI) from 70.83% to 61.95%. Inhibitory derivatives generated during THP included furfural (1.69 mg·mL−1), 5-methylfurfural (2.44 mg·mL−1), and phenol (23.14 mg·L−1), with a theoretical combined inhibition rate of 7.26%. The promotion effect on methane production (66.7%) far exceeded the theoretical inhibition (7.26%), indicating that THP under optimized conditions is effective and environmentally controllable. This study provides a systematic framework for optimizing THP parameters to maximize methane production from agricultural residues.

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Optimization of Thermal Hydrolysis Pretreatment of Corn Straw for Enhanced Methane Production

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202510056• Jan 15, 2026

Pilot Trial on Endogenous Pollution Control in Hejia Ditch, Harbin: Efficacy and Mechanisms of Sediment Elutriation

Authors: WANG Huazhe, MENG Zhaohui, WANG Miao, GUO Wanqian

To support the construction of an ecologically clean small watershed in Harbin, a pilot-scale trial of sediment elutriation was conducted in the Hejia Ditch to evaluate its effectiveness in controlling endogenous pollution and to elucidate the underlying mechanisms. After treatment, sediment organic matter, total nitrogen (TN), and total phosphorus (TP) decreased by 5.11%, 10.19%, and 8.71%, respectively. Water transparency, dissolved oxygen (DO), and oxidation-reduction potential (ORP) increased by 102.46%, 11.07%, and 15.66%, while chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N) removal rates reached 35.67% and 22.65%. The technology effectively removed surface suspended sediment, leaving a stable layer of coarse inorganic particles that formed a clear mud-water interface. Post-treatment, clay content decreased by 8.87%, sand content increased by 12.37%, and median (D50) and 90th percentile (D90) particle sizes increased by 32.39% and 159.97%, respectively. Mechanical disturbance and particle size redistribution enhanced oxygen transfer at the interface, increasing the abundance of facultative anaerobic phyla such as Chloroflexi and Spirochaetes, thereby suppressing the generation of odorous gases (H2S, NH3) and preventing sediment resuspension. Increased microbial diversity and richness improved ecosystem stability and self-purification capacity. These results demonstrate that sediment elutriation is an effective method for controlling endogenous pollution in Hejia Ditch, providing a scientific basis for ecological restoration and long-term management.

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Pilot Trial on Endogenous Pollution Control in Hejia Ditch, Harbin: Efficacy and Mechanisms of Sediment Elutriation

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202511041• Jan 15, 2026

Electron-Driven Processes for Sustained Dark Hydroxyl Radical Generation under Redox Fluctuations in Mangrove Soils

Authors: DONG Junjie, LIN Dong, LIAO Zehua, LU Yaobin, LUAN Tiangang

Hydroxyl radicals (·OH) generated via dark reactions under fluctuating redox conditions significantly influence pollutant degradation and elemental cycling, yet the key electron supply mechanisms driving their sustained production remain unclear. This study aimed to elucidate the electron-driven processes underlying sustained dark ·OH generation in mangrove soils under redox fluctuations. Simulated tidal redox cycles were conducted, and electron donating capacity (EDC), three-dimensional fluorescence spectroscopy, nuclear magnetic resonance, and high-throughput sequencing were employed to analyze the dynamics of different Fe(II) species, key organic matter components, and microbial communities. Results demonstrated that, without exogenous electron donors, mangrove soils exhibited stable ·OH generation potential and EDC. During early redox cycles, total EDC of soil suspensions was dominated by reactive Fe(II), while the contribution of reduced organic matter increased over time, with solid-phase components accounting for 94.5%–97.6% of total EDC. Humic acids in soil organic matter facilitated reversible electron transfer via quinone functional groups, maintaining redox activity. Geothermobacter and Desulfobulbus were identified as dominant iron-reducing bacteria, likely key microorganisms for regenerating the "iron-organic matter" electron sources. This study reveals the mechanisms of endogenous electron donor regeneration and sustained dark ·OH generation mediated by iron and organic matter cycling in mangrove soils, providing theoretical support for understanding the long-term environmental effects of ·OH in tidal environments and its impact on biogeochemical cycles.

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Electron-Driven Processes for Sustained Dark Hydroxyl Radical Generation under Redox Fluctuations in Mangrove Soils

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202510072• Jan 15, 2026

Optimization of CFD Simulation Parameter Settings for Flow Fields with Porous Structures

Authors: ZHU Deqing, CHEN Tingguo, REN Chengjiao, WANG Ke

Porous structures are widely used in hydraulic and pneumatic systems for flow rectification and throttling, reducing velocity, regulating pressure, and improving flow stability. Numerical simulation is a common approach to study such flows, yet the lack of standardized parameter settings often leads to user-dependent errors. This study, based on the CFD software Fluent, systematically analyzes nine key parameters across three core stages: modeling, mesh generation, and solver settings. Under both quasi-2D and 3D configurations, the influence and underlying mechanisms of each parameter on simulation results are revealed, and a reference parameter-setting method is proposed. The method is validated against wind tunnel experiments, showing that the simulated average velocity reduction ratio γS deviates from experimental values by less than 6%, confirming its reliability and applicability. This work provides a basis for standardized parameter settings in numerical simulations of porous structures, enhancing consistency and predictive accuracy.

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Optimization of CFD Simulation Parameter Settings for Flow Fields with Porous Structures

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202510081• Jan 15, 2026

Nitrogen-Vacancy Defective Carbon Nitride Modified Graphite Felt Cathode for Efficient Electrochemical Synthesis of Hydrogen Peroxide

Authors: XIE Wanghong, HU Huawei, ZHANG Xinwan, YANG Zhengwu, LU Zilan, ZHU Leilei, JIA Daqing, ZHANG Lehua

Electrochemical two-electron oxygen reduction (2e−ORR) for hydrogen peroxide (H2O2) synthesis faces challenges of low cathodic catalytic efficiency and complex catalyst preparation. This study prepared nitrogen-vacancy (Nv) rich carbon nitride via one-step pyrolysis, composited with carbon nanotubes (CNT), and loaded onto graphite felt (GF) to fabricate a non-precious metal gas diffusion electrode Nv-C3N4-CNT/GF. The electrode exhibited a three-dimensional fibrous skeleton with interconnected micro-nano hierarchical pores, facilitating efficient electron transport. Electrochemical impedance spectroscopy revealed a low charge transfer resistance of 13.26 Ω, indicating superior electrocatalytic activity and charge transfer efficiency. Single-factor experiments and response surface methodology (RSM) optimization determined optimal conditions: calcination temperature 300 °C, catalyst mass ratio 3:1, Nv-C3N4-CNT loading 0.1 g, current density 40 mA·cm−2, pH 7, and aeration rate 0.1 L·min−1. Under these conditions, H2O2 accumulation reached 1622.73 mg·L−1 after 90 min, which was 1.3 and 1.5 times higher than g-C3N4-CNT/GF and CNT/GF electrodes, respectively. Stability tests showed that after 6 cycles, H2O2 production remained at 1400.52 mg·L−1, and within 960 min, the maximum production reached 2014.04 mg·L−1 with a highest Faradaic efficiency of 54.86%. These results demonstrate the electrode's potential for cyclic use. This study provides a new approach for developing efficient, low-cost electrodes for electrosynthesis of H2O2, offering a reference for green H2O2 production.

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Nitrogen-Vacancy Defective Carbon Nitride Modified Graphite Felt Cathode for Efficient Electrochemical Synthesis of Hydrogen Peroxide

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202512042• Jan 15, 2026

Carbon Deposition Pore-Narrowing Modification of Activated Carbon for Adsorption of Chlorinated Volatile Organic Compounds

Authors: GUO Zhen, LU Hongjie, WEI Fangda, WEN Kai, WU Feng, LI Jinjun

Chlorinated volatile organic compounds (CVOCs) such as dichloromethane (DCM), dichloroethane (DCE), trichloroethylene (TCE), and chlorobenzene (CB) are hazardous air pollutants requiring efficient removal. This study modified a commercial activated carbon (AC) via high-temperature treatment and phenol cracking carbon deposition to tailor its pore structure for enhanced adsorption of small-molecule CVOCs. The modified material (AC-M) exhibited a significant increase in ultramicropore volume (<0.8 nm), leading to a 24.2% increase in DCM adsorption capacity under dry conditions and superior water vapor resistance. Surface oxygen-containing functional groups decreased, enhancing hydrophobicity and mitigating water cluster formation. Adsorption kinetics analysis revealed that AC-M had a 39% higher total adsorption rate constant for DCM and a 22% reduction in mass transfer zone height, indicating faster adsorption. However, for larger CVOCs (DCE, TCE, CB), adsorption capacities slightly decreased due to reduced specific surface area, suggesting their adsorption relies more on micropores of matching size. This work provides a theoretical basis for designing efficient adsorbents for small-molecule CVOCs control.

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Carbon Deposition Pore-Narrowing Modification of Activated Carbon for Adsorption of Chlorinated Volatile Organic Compounds

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202511078• Jan 15, 2026

Multi-step Wet Enhanced Removal of Chlorine and Heavy Metals from Municipal Solid Waste Incineration Fly Ash

Authors: CHEN Hua, LAN Zhicong, HUANG Xingzhu, ZHU Nengwu, JU

Municipal solid waste incineration (MSWI) fly ash contains high levels of soluble chlorine and heavy metals, posing environmental risks. This study employed a sequential wet treatment process (water washing–water washing–acid washing–water washing) at a low liquid-to-solid ratio of 2:1 L·kg⁻¹ to enhance the removal of chlorine and heavy metals. Acetic acid and a mixed acid (acetic acid:sulfuric acid molar ratio 1:1) were used as acid washing agents. Results showed that the soluble chlorine content decreased from 23.96% in the raw ash to approximately 0.6%, achieving a removal efficiency of 97.5%. The 3 mol·L⁻¹ acetic acid group exhibited high removal efficiencies for Pb, Cu, and Cd at 52.97%, 29.60%, and 61.54%, respectively, while increasing the stable fraction of heavy metals. However, excessive dissolution of Ca and Al occurred. The mixed acid group demonstrated a 6.9-fold higher 'calcium retention' capacity compared to acetic acid alone, attributed to the presence of sulfate. After treatment, the leaching concentrations of Pb and Zn were significantly reduced to 0.001 mg·L⁻¹ and 0.05 mg·L⁻¹, respectively, meeting the limits of the 'Technical Specification for Pollution Control of MSWI Fly Ash' (HJ 1134—2020). The treated ash exhibited a CaO-SiO₂-MgO-Al₂O₃ system, suitable for building material applications. This study provides technical support for on-site, building-material-oriented disposal of MSWI fly ash.

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Multi-step Wet Enhanced Removal of Chlorine and Heavy Metals from Municipal Solid Waste Incineration Fly Ash

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202506024• Jan 15, 2026

Simultaneous Distillation Extraction Coupled with Derivatization and GC-MS for Multi-Residue Determination of Phenolic Compounds in Wastewater

Authors: YANG Zijia, ZHOU Yiqi

A simple, economical method for the multi-residue determination of phenolic compounds in wastewater was developed using simultaneous distillation extraction (SDE) combined with derivatization and gas chromatography-mass spectrometry (GC-MS). The effects of extraction time, salt concentration, and pH on extraction efficiency were investigated. Optimal recovery was achieved with the addition of 10 g·L−1 NaCl, adjustment of pH to 4, and extraction with dichloromethane for 2.5 h. Under these conditions, recoveries for spiked concentrations of 100 ng·L−1 and 1,000 ng·L−1 ranged from 58.92% to 91.08% (RSD 2.97%–8.60%, n=3) and 68.83% to 109.88% (RSD 3.06%–7.22%, n=3), respectively. Limits of quantification (LOQ) were between 8.46 and 59.67 ng·L−1, with good linearity over the range of 10.0–1,000 ng·L−1. The method integrates extraction and purification in a single step, reducing sample preparation steps and organic solvent consumption, while improving sample throughput and recovery. Derivatization enhances sensitivity, enabling the detection of ultra-trace phenolic multi-residues in complex matrices such as influent of wastewater treatment plants.

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Simultaneous Distillation Extraction Coupled with Derivatization and GC-MS for Multi-Residue Determination of Phenolic Compounds in Wastewater

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202511076• Jan 15, 2026

Distribution and Enrichment Characteristics of Heavy Metals in Soil and Plants Along an Altitude Gradient in the Northern and Southern Mountains of Lhasa

Authors: LIU Xianlun, AN Baosheng, WANG Chuanfei, LI Jiule, WANG Weicai, WANG Zhongyan

This study investigated the altitudinal distribution and enrichment characteristics of heavy metals in the soil-plant system of the northern and southern mountains of Lhasa on the Tibetan Plateau. Soil and dominant plant samples were collected from three sites along an elevation gradient from 3,650 to 4,150 m, and concentrations of Cr, Cd, Cu, Zn, Ni, As, and Pb were analyzed. Soil heavy metal concentrations ranged from 0.06 to 184.4 mg·kg−1, with all elements except Cd and Pb exceeding local background values. Plant heavy metal concentrations were within normal ranges, indicating no obvious stress. Correlation analysis revealed significant positive correlations between soil Zn and Cd, Cr and Ni, and plant Zn and Cu. Except for Cr, Cu, and Cd, plant and soil concentrations of the same element were significantly correlated. Bioconcentration factor (BCF) analysis showed that most plants had weak enrichment capacity (BCF < 1), but five species, including Ephedra sinica and Rheum likiangense, exhibited BCF > 1 for Cd, with R. likiangense showing the highest BCF of 4.01. The enrichment capacity varied with altitude and species. Potential ecological risk assessment indicated that Cd posed a relatively high risk in plants, warranting attention. This study fills a gap in understanding the spatial distribution and enrichment of heavy metals in this region, providing a scientific basis for ecological management and environmental protection.

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Distribution and Enrichment Characteristics of Heavy Metals in Soil and Plants Along an Altitude Gradient in the Northern and Southern Mountains of Lhasa

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202509004• Jan 15, 2026

Experimental Study on Purification of Acetone Waste Gas by a Novel Composite Absorbent

Authors: CHEN Changtao, MENG Haoyu, ZHOU Hongming, ZHANG Feng, LONG Chao

Acetone, a widely used solvent in the pharmaceutical industry, poses environmental and economic challenges due to its high volatility and the low concentration of acetone in water-based absorbents, which complicates recovery. This study proposes a composite absorbent comprising 1,4-butanediol (BDO), triethylene glycol, sodium citrate, and water, aiming to enhance acetone absorption capacity and enable cost-effective resource recovery. Response surface methodology optimized the absorbent composition to BDO 35%, triethylene glycol 10%, and sodium citrate 5%, achieving an acetone absorption capacity of 51.97 g·kg−1, which is 2.39 times that of pure water (21.77 g·kg−1). Density functional theory (DFT) calculations and AIM topological analysis revealed that BDO forms stronger hydrogen bonds with acetone, characterized by shorter bond lengths and higher electron density, underpinning its superior molecular recognition and absorption capability. Process simulation of absorption-regeneration cycles demonstrated that, compared to pure water, the composite absorbent reduces absorbent consumption by 36.2% and regeneration energy consumption by 41.15% while achieving effluent acetone concentrations below 100 mg·m−3. This multi-scale investigation, spanning macroscopic experiments, molecular mechanisms, and process simulation, validates the feasibility and advantages of BDO-based composite absorbents for VOC control, providing theoretical and data support for the engineering application of alcohol-based absorbents in efficient organic pollutant separation.

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Experimental Study on Purification of Acetone Waste Gas by a Novel Composite Absorbent

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202511002• Jan 15, 2026

Adsorption and High-Temperature Nitrogen Desorption Performance and Mechanism of Granular Activated Carbon for Large-Air-Volume Low-Concentration PCE-Containing Waste Gas

Authors: HUANG Yuting, MA Ling, CAI Yufei, WANG Zhentao, WANG Yuxuan, JIN Ke, JIANG Xingyu, ZHAO Weirong

To treat large-air-volume, low-concentration volatile organic compounds (VOCs) containing tetrachloroethylene (PCE) generated from rubber-metal bonding, this study systematically investigated the adsorption-desorption behavior and interaction mechanisms of PCE, toluene, and methyl isobutyl ketone (MIBK) on granular activated carbon (GAC). Static adsorption experiments showed that PCE adsorption capacity reached 556.6 mg·g−1, while dynamic multi-component adsorption capacity was 179.6 mg·g−1. Kinetic analysis indicated that PCE adsorption was controlled by both intraparticle diffusion and external surface adsorption, whereas toluene and MIBK were primarily intraparticle diffusion-limited. During high-temperature nitrogen desorption, PCE underwent dechlorination, hydrogenation, and recombination, producing trichloroethylene, 1,2-dichloroethane, 1,2-dichloropropane, and HCl, with HCl accounting for 3.61% of the chlorine molar content in adsorbed PCE. After four adsorption-desorption cycles, the iodine value of GAC dropped below the industry standard of 600 mg·g−1; however, water washing and alkali immersion extended the cycle life to 8 and 9 cycles, respectively. The HCl generation pattern in co-adsorption systems was consistent with single-PCE systems. A regeneration process combining alkali immersion and water washing was proposed and integrated into an engineering strategy. Compared to conventional activated carbon adsorption coupled with RTO incineration, the proposed classification strategy reduced annual costs by 49.5×10⁴ CNY. This work provides a cost-effective and safe solution for Cl-VOCs treatment.

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Adsorption and High-Temperature Nitrogen Desorption Performance and Mechanism of Granular Activated Carbon for Large-Air-Volume Low-Concentration PCE-Containing Waste Gas

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202511098• Jan 15, 2026

Determination of 2-Bromostyrene in Water by Headspace Solid-Phase Microextraction Coupled with Gas Chromatography-Mass Spectrometry

Authors: SU Zhaofan, ZHANG Zhong, WU Zihao

A highly sensitive analytical method for the determination of 2-bromostyrene in tap water and surface water was developed and optimized using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). The extraction conditions were systematically optimized via single-factor experiments and an L9(34) orthogonal array with range analysis. The optimal conditions were: sample volume 10 mL, extraction time 30 min, extraction temperature 30 °C, stirring rate 1000 r·min−1, and 2.5 g NaCl as salting-out agent. The method exhibited good linearity over the range 100–5000 ng·L−1 (R² = 0.9994), with a detection limit of 13.8 ng·L−1 and a quantification limit of 55.3 ng·L−1. Recoveries from spiked tap water and surface water samples ranged from 90.2% to 102.2%, with relative standard deviations between 5% and 11%. Statistical tests (normal distribution, F-test, t-test) all yielded P > 0.05, confirming the method's reliability. The method is simple, sensitive, and exhibits minimal matrix effects, making it suitable for routine monitoring of trace 2-bromostyrene in drinking water and surface water.

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Determination of 2-Bromostyrene in Water by Headspace Solid-Phase Microextraction Coupled with Gas Chromatography-Mass Spectrometry

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202511020• Jan 15, 2026

Scenario Simulation and Case Study of Oil Spill Diffusion from Oil Pipelines Crossing Rivers

Authors: LIU Yuanwen, QU Jing, LIU Xiang, WANG Jiuping, WANG Shengxin, WANG Yifei, GAO Zuqiao, LYU Yu, LI Changbin

With the increasing number of oil pipelines crossing rivers, the potential risks of oil leakage and surface spreading to river ecosystems and water environments are becoming more severe. Scenario-based simulation of oil spill diffusion is a prerequisite for effective interception point placement and leakage risk prevention. Numerous factors influence oil spill diffusion, including environmental conditions, river hydrology, and accessibility of emergency resources. This study integrates these factors and multiple dynamic processes to design eight typical scenarios for oil spill diffusion simulation, considering emergency resource locations, river hydrological regimes, and leakage modes. A case study is conducted on an oil pipeline crossing a river in northwest China. Results indicate that the diffusion distance and affected area are primarily controlled by water conditions and emergency resource accessibility. In emergency management, the efficiency of maintenance and repair resources during high-water months should be prioritized. Mechanistically, external forces such as hydraulic and wind forces have a greater influence on diffusion distance, surpassing internal forces like gravity, viscosity, and surface tension within a short time. For river crossings near emergency resources, internal force effects should be considered in oil spill diffusion simulations. When emergency resource arrival times are long, the diffusion distance based on Fay's theory is relatively small and can be neglected in engineering practice. This study provides a computational basis and methodological reference for risk assessment and emergency response to potential oil spills from pipelines crossing rivers, enhancing the scientific and effective nature of risk prevention and emergency handling.

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Scenario Simulation and Case Study of Oil Spill Diffusion from Oil Pipelines Crossing Rivers

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Original ResearchVol. 20, Issue 6 • pp. 100-112DOI: 10.12030/j.cjee.202511010• Jan 15, 2026

Construction of Pd-Ru/Silicalite-1 Bimetallic Catalysts and Their Performance and Mechanism for Complete Methane Oxidation

Authors: WEI Yuwei, LYU Xuanzheng, MA Chunyan, XU Yan, SONG Maoyong

Complete catalytic oxidation of methane requires catalysts with high low-temperature activity, long-term thermal stability, and excellent water resistance for industrial application. This study constructed supported Pd-Ru/S-1 bimetallic catalysts using hydrophobic all-silica zeolite Silicalite-1 as support. Systematic catalytic performance tests evaluated methane oxidation activity, thermal stability, and water resistance, while multiple physicochemical characterizations revealed the reaction mechanism. Results showed that the catalyst with Pd/Ru ratio of 2:1 (2Pd-1Ru/S-1) exhibited optimal comprehensive performance, achieving T90 of 380 °C, maintaining 94% methane conversion at 375 °C for 48 h, and demonstrating excellent water resistance. Mechanistic studies indicated that PdO is the main active phase, and the reaction follows the Eley-Rideal (E-R) mechanism. The electronic synergy between Pd and Ru enhances the interaction between PdO and the support, effectively inhibiting sintering and water poisoning of active components. This study aims to provide a new strategy for industrial catalyst design to advance the industrialization of low-concentration methane catalytic technology, addressing its climate and pollution impacts.

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Construction of Pd-Ru/Silicalite-1 Bimetallic Catalysts and Their Performance and Mechanism for Complete Methane Oxidation

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202512031• Jan 15, 2026

Adsorption Performance and Mechanism of Iron-Modified Sugarcane Bagasse Biochar for Amoxicillin in Aqueous Solution

Authors: LU Juncai, LIU Shuang, QU Jia, YOU Shaohong, JIANG Pingping, JU

The overuse of antibiotics has led to residual amoxicillin (AMX) in aquatic environments, promoting the spread of antibiotic resistance genes (ARGs) and threatening ecological safety. In this study, magnetic iron-modified biochar (Fe-BC) was prepared from agricultural waste sugarcane bagasse via FeCl3·6H2O impregnation and oxygen-limited pyrolysis. The adsorption performance and mechanism of Fe-BC for AMX were systematically investigated. Under conditions of 25 °C, pH 6, and initial AMX concentration of 50 mg·L−1, the adsorption capacity reached 32.61 mg·g−1. Characterization of Fe-BC before and after adsorption, combined with adsorption kinetics, isotherms, and thermodynamic analyses, revealed that adsorption primarily relied on oxygen-containing functional groups. The mechanisms included pore filling, electrostatic interaction, hydrogen bonding, complexation, and π–π interaction. After six thermal regeneration cycles, the removal efficiency of AMX remained above 76%. The specific surface area of Fe-BC increased from 279.20 m2·g−1 to 481.42 m2·g−1, an enhancement of approximately 72.4%. These results provide a technical reference for the resource utilization of agricultural waste and cost-effective treatment of antibiotic-containing wastewater in rural decentralized areas.

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Adsorption Performance and Mechanism of Iron-Modified Sugarcane Bagasse Biochar for Amoxicillin in Aqueous Solution

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202508006• Jan 15, 2026

Enhanced Nitrogen Removal from Landfill Leachate via a Two-Stage A/O–MBBR System Coupled with Anammox

Authors: LIU Jianxi, LIU Hongtao, TAN Yong, GUO Juncheng, LIU Sichen, TAN Cong

Landfill leachate, characterized by high ammonia nitrogen, high organic load, complex toxic components, and low nitrogen removal efficiency, poses significant environmental challenges. To achieve efficient nitrogen removal, a continuous-flow two-stage anoxic/oxic (A/O) moving-bed biofilm reactor (MBBR) system coupled with anaerobic ammonium oxidation (Anammox) was constructed and operated for long-term treatment of actual landfill leachate. After biofilm attachment and multi-gradient acclimation, influent concentrations were gradually increased from low levels (NH4+-N ~200 mg·L−1, COD ~2500–3000 mg·L−1) to high levels (NH4+-N ~1800 mg·L−1, COD ~8500 mg·L−1). During stable operation, average removal efficiencies of NH4+-N and COD reached 97.7% and 66.8%, respectively, with total nitrogen (TN) removal efficiency improving to 93.9%. Along the reactor, the first A/O stage achieved major organic degradation and ammonia oxidation, while the second stage facilitated nitrite accumulation and promoted Anammox for synergistic nitrogen removal. High-throughput sequencing revealed Proteobacteria as the dominant phylum (>50%), with denitrifying genera such as Azoarcus and Thauera significantly enriched. Planctomycetota abundance increased from 0.6% to 3.7%, and Candidatus Kuenenia was detected, confirming successful Anammox colonization and participation in nitrogen removal. This study validates the efficient combined nitrogen removal mechanism of the A/O–MBBR system with Anammox, providing theoretical basis and technical support for engineering treatment of high-ammonia wastewater.

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Enhanced Nitrogen Removal from Landfill Leachate via a Two-Stage A/O–MBBR System Coupled with Anammox

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202512064• Jan 15, 2026

Cerium-Based Magnetic Y-Type Molecular Sieve for Deep Removal of Fluoride Ions from Water

Authors: FANG Wanrong, QIU Zhaofu, WANG Yuan, LI Shangshu, JIN Xibiao

With increasingly stringent discharge standards for fluoride-containing wastewater, there is an urgent need for cost-effective, easily operable adsorbents capable of rapid adsorption and separation for deep defluorination. In this study, a novel adsorbent, Ce-FMSY, was successfully prepared by co-precipitation of cerium (Ce) and Fe3O4 onto Y-type molecular sieve (MSY). The effects of Ce/Fe mass ratio, adsorption time, initial solution pH, and coexisting anions on adsorption performance were systematically investigated. Results showed that at a Ce loading of 1.0% and Ce/Fe mass ratio of 2:1, Ce-FMSY rapidly adsorbed 86.2% of F− within 30 min, with a maximum adsorption capacity of 4.139 mg·g−1. The saturated magnetization of Ce-FMSY was 13.4 emu·g−1, enabling rapid solid-liquid separation. The adsorbent maintained a stable fluoride removal rate of 77.1%–96.8% over an initial pH range of 3–9. Adsorption kinetics and isotherm fitting indicated that F− adsorption onto Ce-FMSY followed pseudo-second-order kinetics and the Freundlich model, suggesting chemisorption as the dominant mechanism, involving rapid diffusion, surface complexation, and valence transformation reactions. After five adsorption-desorption cycles, the adsorption capacity slightly decreased and then stabilized, with F− removal efficiency maintained at approximately 72.3% of the initial value. This study provides data support and theoretical reference for deep fluoride removal from wastewater.

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Cerium-Based Magnetic Y-Type Molecular Sieve for Deep Removal of Fluoride Ions from Water

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202510044• Jan 15, 2026

Catalytic Conversion Behavior and Degradation Mechanisms of Sulfur-Containing Multi-Pollutants such as Thiols and Thioethers: A Review

Authors: FENG Yu, FANG Jian, XU Zhizhi, LAI Junyu, LU Jichang, LUO Yongming

The efficient treatment of sulfur-containing volatile organic compounds (S-VOCs) has become a critical task for air pollution control and green low-carbon transition under China's 14th Five-Year Plan. Industrial emissions often contain multiple S-VOC species, whose interactions can complicate degradation pathways, generate uncontrollable byproducts, and deactivate catalysts, limiting practical application. This review systematically summarizes the past decade of research on catalytic degradation of thiols and thioethers in multi-pollutant systems, focusing on competitive adsorption mechanisms, interfacial reaction pathways, and environmental factor regulation. Performance differences and reaction mechanisms across various catalyst systems under coexisting S-VOCs and inorganic sulfur are compared. Key findings indicate that mixed thiol systems exhibit faster deactivation than single-component systems due to temperature-dependent competitive adsorption and pathway switching, governed by molecular size–active site matching. Strategies such as metal–support strong interactions, zeolite confinement, nanocluster effects, and single-atom catalysts have improved activity and stability. However, dynamic competition mechanisms at active sites remain unresolved. Future research should develop atomic/molecular-level characterization techniques and multi-variable kinetic models, and shift from end-of-pipe purification to resource recovery, e.g., converting H2S and thiols into high-value chemicals like methanethiol, achieving dual goals of pollution control and sulfur resource recycling.

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Catalytic Conversion Behavior and Degradation Mechanisms of Sulfur-Containing Multi-Pollutants such as Thiols and Thioethers: A Review

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511043• Jan 15, 2026

Dominant Role of Digestate Biochar-Modified Zero-Valent Iron Interfacial Structure in Regulating Nitrobenzene Reduction Efficiency

Authors: LIU Daicheng, LI Yongqiang, CHEN Jingkang, XIONG Lei, GUO Dajiang, JU

Zero-valent iron (ZVI) suffers from surface passivation and low electron utilization in reductive removal of nitrobenzene (NB). To address these issues, a ball-milled iron/digestate biochar composite (BM-Fe/DBC) was prepared and compared with a physically mixed counterpart (PM-Fe/DBC). Characterization revealed that ball milling tightly embedded ZVI particles into the carbon matrix, forming Fe–C chemical bonds and a strong interfacial coupling structure that established efficient electron transfer channels. This structure significantly enhanced the micro-galvanic effect between iron and carbon, yielding superior reduction performance across a wide pH range (3–9). Under optimal conditions (Fe:C mass ratio 2:1, dosage 1.0 g·L−1, pH 5), BM-Fe/DBC achieved 79.9% NB removal, and the generation of aniline (AN) was 1.85 times that of PM-Fe/DBC. Mechanistic studies indicated that the intimate Fe–C interfacial coupling promoted sustained ZVI corrosion and enhanced the production of indirect reducing species, including adsorbed Fe(II) and atomic hydrogen (H*). Electrochemical analyses showed that BM-Fe/DBC exhibited a lower corrosion potential, a higher corrosion current density (approximately 2.15 times higher), and lower charge transfer resistance, kinetically confirming its superior electron transfer capability. These findings reveal that constructing strong interfacial coupling in iron–carbon composites via mechanochemical methods can effectively overcome key limitations of ZVI in reduction reactions, providing a theoretical basis and practical pathway for designing high-performance water treatment materials.

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Dominant Role of Digestate Biochar-Modified Zero-Valent Iron Interfacial Structure in Regulating Nitrobenzene Reduction Efficiency

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202510042• Jan 15, 2026

Empowering a Chinese-Characteristic Waste Classification Model with Mid-End Intelligent Sorting

Authors: JIANG Zixuan, WEN Zongguo, HU Yupeng, WU Jianyang, WU Jiancheng, ZHANG Liping

Given China's escalating municipal solid waste (MSW) generation and the limitations of current classification schemes, this study proposes a novel waste classification model centered on mid-end intelligent sorting technology. The approach integrates targeted pretreatment with multimodal visual recognition and robotic grasping to efficiently sort complex household waste, while compact equipment innovations adapt to the low-value characteristics of recyclables. An engineering demonstration case shows that the technology can effectively recover low-value recyclables comprising 15%–30% of mixed MSW. If applied at 5% of a case city's waste transfer stations, approximately 5×10^4 t of recyclables could be sorted annually. Preliminary estimates indicate a 20% return on investment for operators at an 80 t·d−1 scale. The study demonstrates that mid-end intelligent sorting offers a technically feasible and economically sustainable solution to reduce fiscal expenditure on waste classification while improving efficiency.

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Empowering a Chinese-Characteristic Waste Classification Model with Mid-End Intelligent Sorting

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202512045• Jan 15, 2026

Electrocatalytic Degradation of Phenol by Sn-Sb Co-doped Ti/SnO2 Electrode: Performance and Mechanism

Authors: XIE Haoyu, WANG Tianyu, LI Yanhong, LIU Ruiping

To optimize the anode structure of Ti/SnO2-based electrodes in electrochemical advanced oxidation processes (EAOPs) and enhance their electrocatalytic activity and stability, Sn-Sb co-doped Ti/SnO2 electrodes were fabricated via a sol-gel method. The degradation performance and mechanism were evaluated using phenol as a model pollutant. Three electrodes were prepared with different Sn/Sb molar ratios: Ti/SnO2 (10:0), Ti/Sb (0:10), and Ti/SnO2-Sb (9:1). Characterization by XRD, SEM, and electrochemical tests revealed that the Sn-Sb co-doped electrode exhibited a dense surface, higher oxygen evolution potential (OEP), larger electrochemically active surface area, and lower charge transfer resistance compared to single-doped counterparts. In constant-current electrolysis experiments (20 mA·cm−2, pH=5, 0.1 mol·L−1 Na2SO4), the co-doped electrode achieved superior phenol and TOC removal efficiencies and higher apparent rate constants, with the lowest specific energy consumption per unit TOC removal. Radical quenching and intermediate analysis indicated that hydroxyl radicals (·OH) were the dominant reactive species. The degradation pathway involved aromatic ring hydroxylation, ring opening, and further mineralization of short-chain carboxylic acids. Sn-Sb co-doping enhanced the generation of ·OH by increasing surface adsorbed oxygen and defect site density. This synergistic doping strategy significantly improved the electrocatalytic activity and service life of Ti/SnO2-based anodes, providing a basis for the rational design of anode materials for EAOPs in treating refractory organic wastewater.

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Electrocatalytic Degradation of Phenol by Sn-Sb Co-doped Ti/SnO2 Electrode: Performance and Mechanism

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511095• Jan 15, 2026

Characteristics of Autumn–Winter Daily Atmospheric Dustfall Pollution in the Core Area of Beijing

Authors: HUANG Yu-hu, LIU Li-yang, LI Bei-bei, WANG Yu, LIANG Jing, ZHAO Yu, QIN Jian-ping

To address the low temporal resolution of conventional monthly dustfall monitoring and the lack of component information, this study proposed a daily dustfall measurement method that adds a filtration step to the Chinese standard method, referencing international standards. Using a sand-core filtration device with quartz or mixed cellulose ester membranes, the method achieved a spiked recovery of 101.1% ± 1.2%, good parallelism (y = 0.95x + 0.28), and satisfactory temporal closure. During autumn–winter (November 2020 to March 2021) at a representative site in Xicheng District, Beijing, daily dustfall ranged from 0.06 to 2.33 t·(km²·d)−1. Days with daily dustfall exceeding 0.7 t·(km²·d)−1 accounted for only 4% of the sampling days but contributed 25% of the total dustfall, with high values mainly occurring in January, March, and December. The insoluble fraction averaged 83% ± 12%, and a logarithmic model (y = 9.36ln(x) + 99.98) was established to estimate the insoluble proportion from insoluble dustfall (x, ≤1.00). Daily dustfall showed a strong positive correlation with average wind speed, and an exponential prediction model (y = 0.06e0.61x) was derived. Windy conditions (≥3 on the Beaufort scale) significantly amplified dustfall. The study recommends suspending earthwork, covering bare ground, and increasing watering frequency during high-wind alerts to mitigate dust pollution. This work provides a reliable method for high-resolution dustfall monitoring and insights for targeted pollution control in urban core areas.

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Characteristics of Autumn–Winter Daily Atmospheric Dustfall Pollution in the Core Area of Beijing

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511055• Jan 15, 2026

Numerical Simulation of Water Environment in the Mountainous River of the Upper Heihe River Based on MIKE21

Authors: WANG Yu, WEI Xiaozhen, LUO Tianfeng, WANG Hao, TIAN Miao, SUN Chao, ZHANG Xiaolong, REN Weilong, HU Feiyan

To systematically investigate the spatiotemporal distribution of hydrodynamics and water quality under cascaded hydropower development in the upper Heihe River, a MIKE21-based water environment model was constructed for the mountainous reach. The model simulated the dynamic changes of total phosphorus (TP), total nitrogen (TN), and ammonia nitrogen (NH3-N) from January to August 2023. Calibration and validation against field data showed good performance: the hydrodynamic model achieved a coefficient of determination (R2) of 0.89 and a mean relative error (MRE) of 11.3%; the water quality model achieved an average R2 of 0.86 and an average MRE of 14.21%. Hydrodynamic simulations revealed average flow velocities of 1.78, 0.72, and 0.36 m·s−1 during wet, normal, and dry periods, respectively. Natural river sections exhibited high velocities up to 4.3 m·s−1, while reservoir sections had near-stagnant flow due to hydraulic structures. Water quality simulations indicated that TN and NH3-N concentrations were higher in dry and normal periods, whereas TP was higher in the wet period. Spatially, concentrations in reservoir sections exceeded those in natural sections: natural sections had TP, TN, and NH3-N concentrations of 0.07–0.10, 0.25–0.50, and 0.025–0.250 mg·L−1, respectively, while reservoir sections had 0.12–0.17, 0.60–0.80, and 0.10–0.45 mg·L−1. These findings provide scientific references for water environment management in the Heihe River and similar inland river basins.

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Numerical Simulation of Water Environment in the Mountainous River of the Upper Heihe River Based on MIKE21

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202512057• Jan 15, 2026

Preparation of Slag-Based Carbon Powder-Sodium Alginate Composite Membrane and Its Efficient Adsorption of Cr(VI) from Aqueous Solutions

Authors: CHEN Qiuyi, ZHANG Zhe, HUO Qiang, MO Yuanyuan, JU

A novel slag-based carbon powder-sodium alginate composite membrane was fabricated by incorporating purified slag-derived carbon powder into a sodium alginate matrix, followed by dual crosslinking with polyethyleneimine and glutaraldehyde. The membrane was designed to achieve waste-to-treat-waste objectives, enhance the resource value of industrial slag, and provide an efficient, regenerable adsorbent for Cr(VI) removal from water. Adsorption performance was systematically evaluated. Optimal adsorption occurred at pH 2, with elevated temperature and initial Cr(VI) concentration favoring uptake; equilibrium was reached at approximately 73 h. The adsorption kinetics followed a pseudo-second-order model, and isotherm data fitted the Langmuir model, yielding a theoretical maximum adsorption capacity of 471.970 mg·g−1. Thermodynamic analysis indicated a spontaneous, endothermic process. In simulated wastewater containing multiple metal ions, competitive effects moderately reduced adsorption capacity. After three adsorption-desorption cycles, the membrane retained good structural stability despite a decline in capacity. Characterization via SEM-EDS, FTIR, and XPS revealed a porous structure and the involvement of functional groups such as –COOH and –NH2, with partial reduction of Cr(VI) to Cr(III). The adsorption mechanism was attributed to synergistic electrostatic interaction, chemical coordination, and redox reactions.

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Preparation of Slag-Based Carbon Powder-Sodium Alginate Composite Membrane and Its Efficient Adsorption of Cr(VI) from Aqueous Solutions

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202504023• Jan 15, 2026

Interpretation of the National Standard GB/T 19515—2023: Requirements and Calculation Methods for Recyclability Rate and Recoverability Rate of Road Vehicles

Authors: ZHANG Tongzhu, HOU Meng

The national standard GB/T 19515—2023, titled "Road vehicles - Recyclability and recoverability - Requirements and calculation methods," has been officially released and implemented. This standard is crucial for guiding automotive manufacturers in selecting recyclable materials for new products and enhancing the potential recyclability and recoverability of vehicles. This paper provides a comprehensive interpretation of the standard, covering its background, significance, technical requirements for the two rates (recyclability rate and recoverability rate), and the calculation methods. The standard aims to assist automotive enterprises in establishing a calculation system for these rates, thereby improving the recyclability performance of vehicles, reducing waste from end-of-life vehicles, and promoting the circular economy within the automotive industry. Key aspects include the alignment with international standards such as ISO 22628 and EU directives, the historical evolution of the standard from 2004 to 2023, and the detailed calculation methodology based on four stages of end-of-life vehicle processing: pre-treatment, dismantling, metal separation, and treatment of non-metallic residues. The paper also highlights the importance of design-phase considerations and the need for manufacturers to collect accurate material data from their supply chains. Future improvements to the standard are discussed, including expanding vehicle type coverage and refining material identification requirements.

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Interpretation of the National Standard GB/T 19515—2023: Requirements and Calculation Methods for Recyclability Rate and Recoverability Rate of Road Vehicles

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202512059• Jan 15, 2026

Construction of Thiol-Functionalized Chitin and Its Adsorption Performance and Mechanism for Pd(II)

Authors: LUO Yi, YAN Linzhe, LI Bo, XUE Zhenluan, SHAO Penghui

Recovery of palladium from Pd-bearing wastewater is economically and environmentally significant. Adsorption is a promising method due to its simplicity, low cost, and high efficiency. In this study, a novel thiol-modified adsorbent (CHT-SH) was synthesized via one-step functionalization of inexpensive chitin (CHT) with thioglycolic acid. At room temperature and pH=2, CHT-SH exhibited an experimental adsorption capacity of 223.67 mg·g−1 for Pd(II), which was approximately 7 times higher than that of pristine CHT (30.6 mg·g−1). Kinetic and isotherm studies indicated that the adsorption process followed the pseudo-second-order kinetic model and the Langmuir isotherm model, with a maximum theoretical adsorption capacity of 248.89 mg·g−1, suggesting monolayer chemisorption. Characterization (FTIR, SEM, XPS, XRD) and density functional theory (DFT) calculations revealed that the adsorption mechanism primarily involved synergistic coordination of nitrogen and sulfur atoms, along with electrostatic interactions. Furthermore, CHT-SH demonstrated good reusability, retaining stable adsorption capacity after five adsorption-desorption cycles. Compared to other adsorbents that rely on redox mechanisms and are costly, CHT-SH offers comprehensive advantages. This work provides a cost-effective and efficient adsorbent for Pd(II) recovery from wastewater, offering technical support and theoretical reference for practical applications.

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Construction of Thiol-Functionalized Chitin and Its Adsorption Performance and Mechanism for Pd(II)

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202512052• Jan 15, 2026

Performance of Iron-Carbon-Manganese Ore Composite Substrate Constructed Wetland for Simultaneous Removal of Nitrogen and Tetracycline

Authors: CHENG Yuwei, LU Xixin, ZHANG Haiqing, HAO Yinli, QU Dan, LIU Yongze, JIN Rencai, HUANG Jinkun, ZHU Yan

Constructed wetlands (CWs) with conventional substrates often exhibit limited removal of nitrogen and antibiotics from secondary effluent. This study developed an iron-carbon-manganese ore (Fe-C-Mn) composite substrate CW to enhance simultaneous removal of nitrogen and tetracycline (TC). Under influent TC of 2 mg·L−1 and total nitrogen (TN) of 15 mg·L−1, the Fe-C-Mn system achieved average TC removal of 91.3%, significantly higher than the gravel control (27.2%). TN and nitrate nitrogen (NO3−-N) removals reached 71.7% and 83.3%, respectively, versus 7.8% and 1.2% in the control. Substrate analysis revealed increased surface roughness and synergistic generation of active components (Fe(II)/Fe(III) and Mn(II)), driving autotrophic denitrification and TC biodegradation/chemical degradation. Microbial community analysis indicated reduced overall diversity but selective enrichment of potential TC degraders (e.g., Trichosporon, Bacillota) and denitrifiers (e.g., unclassified_f_Rhodocyclaceae). TC degradation pathways included demethylation, hydroxylation, and ring-opening, ultimately yielding small metabolites. These findings provide theoretical and technical support for enhanced removal of antibiotics and nitrogen from secondary effluent using CWs.

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Performance of Iron-Carbon-Manganese Ore Composite Substrate Constructed Wetland for Simultaneous Removal of Nitrogen and Tetracycline

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202512025• Jan 15, 2026

Stratification of Persulfate in Porous Aquifers and Its Impact on Remediation of Light Non-Aqueous Phase Liquid Contamination

Authors: YANG Wei, CHEN Yudao, JU, LI Weixuan, TANG Dongbo, DU Liu, YAN Xue

Persulfate (PS) is a common oxidant in in-situ chemical oxidation (ISCO) for groundwater organic contamination, but its vertical concentration stratification may lead to inefficient remediation of light non-aqueous phase liquids (LNAPLs). To investigate the vertical stratification characteristics of PS in porous aquifers and its impact on LNAPLs remediation, static water column experiments and flowing water sand tank experiments were conducted. The migration behavior of PS under non-slow-release and slow-release conditions was compared, with Br− as a reference tracer and benzene, toluene, and xylene (BTX) as LNAPLs contaminants. Results showed that in static water columns, Br− exhibited weak vertical migration, short migration distance, and a low decay rate (0.009 d−1), consistent with a stable tracer. In contrast, PS showed strong vertical migration, with concentrations increasing with depth; under slow-release conditions, the concentration difference between the top and bottom of the column could reach two orders of magnitude. Br− migration was dominated by molecular diffusion (effective diffusion coefficient 2.2×10−9 m2·s−1), while PS migration was driven by both diffusion and density. Under slow-release conditions, the average PS decay rate was 0.072 d−1, slightly higher than the non-slow-release rate (0.059 d−1). In both column and sand tank experiments, BTX exhibited a distinct shallow-layer distribution, contrasting with PS. When the aquifer thickness is large, PS stratification limits its contact with LNAPLs contaminants, increasing remediation cost and difficulty. These findings provide theoretical reference for PS-based ISCO remediation of LNAPLs in porous aquifers.

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Stratification of Persulfate in Porous Aquifers and Its Impact on Remediation of Light Non-Aqueous Phase Liquid Contamination

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511005• Jan 15, 2026

Nitrogen Removal Performance of Tidal Flow Constructed Wetlands Based on α-Fe2O3/Volcanic Rock Mixed Substrate

Authors: GONG Jiaxing, GUO Jie, LUO Xiao, ZHANG Rui

To enhance the adsorption performance of volcanic rock for nitrogen in water, an α-Fe2O3/volcanic rock composite was successfully prepared via ferric citrate impregnation and calcination. Its adsorption characteristics for NH4+-N and NO3−-N and application in tidal flow constructed wetlands (TFCWs) were systematically investigated. Results showed that the adsorption kinetics of both nitrogen forms followed a pseudo-second-order model, indicating chemisorption dominance. Langmuir and Freundlich isotherm models both fitted the data, suggesting coexistence of monolayer and multilayer adsorption. The saturated adsorption capacities of α-Fe2O3/volcanic rock for NH4+-N and NO3−-N were 0.055 mg·g−1 and 0.067 mg·g−1, respectively. In TFCWs using this composite as substrate, average removal efficiencies for NH4+-N and NO3−-N reached 72.51% and 68.13%, respectively. Furthermore, microbial community abundance and diversity in the wetland system significantly increased, indicating that α-Fe2O3 introduction effectively enhanced microbial activity, thereby improving nitrogen removal efficiency.

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Nitrogen Removal Performance of Tidal Flow Constructed Wetlands Based on α-Fe2O3/Volcanic Rock Mixed Substrate

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202512015• Jan 15, 2026

Stabilization Efficiency and Mechanisms of Iron-Manganese Phosphate Modified Biochar for Cadmium, Lead, and Zinc Co-Contaminated Soil

Authors: LI Jiayue, ZHU Bin, ZUO Jianfen, YAN Ximing, LIU Yang, PAN Bo, HUANG Jianhong, JU

The co-contamination of cadmium (Cd), lead (Pb), and zinc (Zn) in agricultural soils near mining areas poses significant risks to ecosystems and human health. Conventional stabilization materials often exhibit insufficient performance for Zn, particularly in multi-metal systems. This study synthesized a novel composite biochar (PFMBC) by loading phosphate and iron-manganese oxides onto biochar via phosphoric acid impregnation followed by secondary pyrolysis at 600 °C. The stabilization efficiency of PFMBC was evaluated against pristine biochar (BC) and iron-manganese modified biochar (FMBC) in a soil collected from a lead-zinc mining area (total Cd: 43.77 mg·kg−1, Pb: 3355.94 mg·kg−1, Zn: 1296.57 mg·kg−1). After 60 days of incubation with 5% PFMBC, the DTPA-extractable (bioavailable) fractions of Cd, Pb, and Zn decreased by 73.44%, 90.10%, and 69.33%, respectively, significantly outperforming BC and FMBC. Sequential extraction indicated that PFMBC promoted the transformation of Cd, Pb, and Zn from acid-soluble and reducible fractions to more stable residual fractions. Characterization via FTIR, SEM, and XRD revealed enhanced surface functional groups and the formation of stable mineral phases. The synergistic effects of phosphate precipitation, iron-manganese oxide adsorption, and surface complexation contributed to the superior stabilization, particularly overcoming the challenge of Zn immobilization. These findings demonstrate that PFMBC is a promising amendment for the remediation of Cd-Pb-Zn co-contaminated soils, offering high efficiency and long-term stability.

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Stabilization Efficiency and Mechanisms of Iron-Manganese Phosphate Modified Biochar for Cadmium, Lead, and Zinc Co-Contaminated Soil

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511027• Jan 15, 2026

Nutrient Release Characteristics of Aquaculture Sludge through Anaerobic Acidification in an Aquaponics System

Authors: ZI Yongxia, HE Xinmeng, GAO Yueshu, LI Chunjie

Aquaponics systems integrate aquaculture and hydroponics to recycle resources, yet nutrient recovery from aquaculture sludge remains inefficient. This study investigated anaerobic acidification as an alternative to conventional anaerobic digestion, which suffers from long conversion cycles. Batch experiments compared two sludge loading rates: high (13.22 kg·kg−1) and low (4.61 kg·kg−1) (mass of sludge per mass of anaerobic inoculum). Under low loading, soluble chemical oxygen demand (SCOD) exhibited a single peak, reaching a maximum organic solid conversion of 68.2% at 70.5 h. In contrast, high loading produced three SCOD peaks with an average peak conversion efficiency of only 26.9% at 27.5 h and higher residual concentrations. Ammonia nitrogen conversion was slightly higher under low loading (64.8%) than high loading (62.2%), while orthophosphate conversion was markedly superior (95.7% vs. 76.4%). The optimal hydraulic retention time for low-loading operation was 144 h, corresponding to an organic loading rate of 0.77 kg·(kg·d)−1. Under these conditions, the produced ammonia and phosphate can be effectively recovered without adversely affecting water quality, as the biofilter converts ammonia to nitrate for plant uptake. Microbial analysis revealed that low-loading conditions favored the dominance of Acinetobacter (relative abundance 66.6%), which likely enhances organic degradation and nutrient release. These findings demonstrate that anaerobic acidification under low loading is a promising strategy for efficient nutrient recovery in aquaponics, offering a shorter conversion time and higher nutrient yields than traditional methods.

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Nutrient Release Characteristics of Aquaculture Sludge through Anaerobic Acidification in an Aquaponics System

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202510071• Jan 15, 2026

Removal of Nitrate from Livestock Wastewater Using Composite Carbon Sources of Corncob and Polycaprolactone

Authors: TANG Qiang, YAN Xiaoping, HE Xiao, LIU Siqi, ZHAO Shengwei, JIANG Rong, YANG Zhanbiao

Carbon source is a critical factor driving heterotrophic denitrification, yet the low carbon-to-nitrogen ratio (C/N) of livestock wastewater limits this process. This study developed novel composite carbon sources by combining corncob (CC) and polycaprolactone (PCL). Static carbon release and denitrification experiments were conducted to evaluate carbon release patterns and nitrogen removal performance. Results showed that the carbon release index (n) was below 0.45, indicating Fickian diffusion as the dominant release mechanism. The composite carbon source prepared at a CC:PCL mass ratio of 3:2 (denoted YP4) achieved a nitrate nitrogen removal efficiency of 94.76%, with effluent ammonia nitrogen meeting the discharge limits of GB 18596-2001. High-throughput sequencing revealed that YP4 increased the relative abundance of genera capable of denitrification and biopolymer degradation (e.g., Aeromonas, Novosphingobium, Bacteroides, and Clostridium sensu stricto), thereby enhancing heterotrophic denitrification and nitrogen removal. These findings provide a novel approach for selecting and preparing external carbon sources for biological heterotrophic denitrification of low C/N wastewater.

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Removal of Nitrate from Livestock Wastewater Using Composite Carbon Sources of Corncob and Polycaprolactone

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202512014• Jan 15, 2026

Application of Microporous Bio-Gravel for Microecological Remediation of Degraded Mine Soils

Authors: WANG Jingwen, HU Hao, LIU Yongjie, LI Jingguo, QU Laiye, ZHANG Naili, TAO Siqi

Mining activities cause severe soil degradation and microbial diversity loss, impeding ecological restoration. This study evaluated the effects of a novel soil amendment, microporous bio-gravel (MBG), on bacterial and fungal community structure and function in degraded soil from the Baiyinhua open-pit mine, Inner Mongolia. A pot experiment with four MBG-to-soil volume ratios (CK, L=1:3, M=1:2, H=1:1) was conducted, with a simplified plant community and uniform fertilization. After 180 days, soil samples were analyzed via high-throughput sequencing and bioinformatics. Results showed that the medium ratio (M) significantly increased fungal Shannon index and evenness, while the high ratio (H) negatively affected bacterial communities. At phylum and genus levels, MBG promoted enrichment of Cyanobacteria and specific functional groups (e.g., nitrogen-fixing bacteria, Bacillus). Co-occurrence network analysis revealed peak complexity, modularity, and average degree in bacterial and fungal networks under the M treatment. Functional prediction indicated significant enrichment of pathways related to lipopolysaccharide biosynthesis, nitrotoluene degradation, and plant-pathogen interactions, alongside increased abundance of saprotrophic and ectomycorrhizal fungi. Mantel and VPA analyses showed that MBG indirectly regulated microbial community structure by improving soil physicochemical properties and plant traits, with stronger effects on fungi than bacteria. In conclusion, MBG optimizes the soil microhabitat and plant-soil-microbe interactions, modulating microbial diversity, network complexity, and functional potential. The medium ratio (1:2) was most effective, demonstrating potential for ecological restoration of degraded mine soils.

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Application of Microporous Bio-Gravel for Microecological Remediation of Degraded Mine Soils

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511025• Jan 15, 2026

Carbon Emission Accounting and Reduction Pathways for a Municipal Wastewater Treatment Plant in Lanzhou

Authors: XU Wen, YANG Rui, LIU Xiangrui, MAO Yaoru, CHENG Xiuwen

Under the national carbon peak and carbon neutrality goals, carbon reduction in municipal wastewater treatment plants (WWTPs) has been largely overlooked, yet accurate accounting is the first step toward mitigation. This study establishes a carbon emission accounting method for a municipal WWTP in Lanzhou, covering the operation and maintenance phase, to identify key emission sources and propose feasible reduction pathways. The results show that the total annual carbon emission in 2023 was 61,399.80 t CO2-eq, with an emission intensity of 0.71 kg CO2-eq per tonne of wastewater treated. Monthly emissions were relatively stable, with a coefficient of variation of 3.46%. Direct emissions accounted for 47.47% of the total, with N2O being the dominant contributor (61.89% of direct emissions), followed by CO2 (30.88%) and CH4 (7.23%). Indirect emissions accounted for 52.53%, dominated by electricity consumption (95.15% of indirect emissions). Pearson correlation analysis revealed that direct carbon emissions per tonne were significantly correlated with influent BOD5 concentration, influent TN concentration, BOD5 removal rate, and TN removal rate (P < 0.01). Sensitivity analysis identified sewer retention time, fossil carbon fraction in influent, and solids retention time as the most influential parameters, with sensitivity coefficients of 0.42, 0.35, and 0.28, respectively. Considering uncertainties in emission factors and monitoring errors, the 95% confidence interval for annual total emissions was 55,200–67,600 t CO2-eq, corresponding to an emission intensity of 0.64–0.79 kg CO2-eq per tonne. Recommendations focus on three synergistic reduction strategies: reducing source emissions, lowering energy consumption, and enhancing carbon compensation.

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Carbon Emission Accounting and Reduction Pathways for a Municipal Wastewater Treatment Plant in Lanzhou

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202509120• Jan 15, 2026

Intensity-Based Carbon Reduction Benefits of 'Zero-Waste City' Construction: A Case Study of Mianyang

Authors: LONG Fei, JIANG Zhonglin, TANG Xiujuan, JIANG Yingying, DING Xia, CHEN Mengjun, JU (Corresponding Author: CHEN Mengjun)

The 'Zero-Waste City' initiative, centered on source reduction, resource utilization, and safe disposal of solid waste, aims to minimize environmental impact. To quantitatively assess its carbon reduction contribution, this study took Mianyang as a case, systematically collecting data on solid waste generation, utilization, and disposal across industrial, agricultural, and other sectors from 2021 to 2024. Employing an improved WARM model and emission factor method, and incorporating generation, utilization, and disposal intensities, the carbon reduction benefits before (2021–2022) and after (2023–2024) the initiative were evaluated. Results show that despite significant improvements in comprehensive utilization and safe disposal rates, total solid waste generation increased, leading to a net negative carbon effect of -127.6×10^4 tCO2eq based on absolute quantities. However, after stripping economic and population growth factors, intensity-based accounting revealed a cumulative reduction of 10.8×10^4 tCO2eq, demonstrating significant synergistic benefits. The industrial sector contributed the most, with a reduction of 40.2×10^4 tCO2eq, driven by green transformation and enhanced utilization capacity. Conversely, the rising intensity of domestic solid waste generation resulted in a negative benefit of -46.1×10^4 tCO2eq, highlighting a key area for future improvement. The study underscores the necessity of considering both intensity and absolute quantity dimensions in evaluating rapidly developing cities. These findings provide practical evidence and reference pathways for advancing 'Zero-Waste City' construction and synergistic pollution reduction and carbon mitigation under the 'dual carbon' goals.

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Intensity-Based Carbon Reduction Benefits of 'Zero-Waste City' Construction: A Case Study of Mianyang

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511021• Jan 15, 2026

Synergistic Cadmium Immobilization in Paddy Soil by Klebsiella aerogenes Wn Combined with Hydroxyapatite

Authors: ZHAI Ke, SU Yuan, GUAN Huize, TANG Xi, RAO Zhongxiu, HUANG Fengqiu, TANG Chongjian

Phosphate-solubilizing microorganisms (PSM) can immobilize cadmium (Cd) by dissolving insoluble phosphates and inducing the precipitation of stable Cd-phosphate minerals. However, the low bioavailability of soil phosphorus and the relatively low Cd2+ concentrations often limit the efficiency of microbial-induced phosphate precipitation (MIPP). This study proposed a combined strategy using the phosphate-solubilizing bacterium Klebsiella aerogenes Wn (Wn) and hydroxyapatite (HAP) to enhance Cd immobilization in paddy soil. Pot experiments were conducted to evaluate the effects on soil Cd availability and rice grain Cd accumulation, and the underlying mechanisms were investigated. Results showed that the combined treatment stabilized soil pH between 5.8 and 6.7 and electrical conductivity between 66 and 290 μS·cm−1, while increasing available phosphorus by 4%–67%. The optimal treatment (T4: 8 g·kg−1 HAP + 3.75×10^9 cfu·kg−1 Wn) reduced soil available Cd by 40.2% and decreased rice grain Cd to 0.0699 mg·kg−1, which is 65% below the national food safety limit. Microbial community analysis confirmed successful colonization of Wn. Pure culture experiments demonstrated that Wn induced phosphate precipitation, forming a more stable cadmium hydroxyapatite mineral [Ca3.9(Ca4.7Cd0.7)(PO4)6(OH)1.8]. The combined Wn-HAP treatment is an efficient strategy for remediating Cd-contaminated farmland, with significant potential for ensuring agricultural product safety and promoting soil remediation.

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Synergistic Cadmium Immobilization in Paddy Soil by Klebsiella aerogenes Wn Combined with Hydroxyapatite

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511054• Jan 15, 2026

S-scheme Bi6O5(OH)3(NO3)5·3H2O/BiOBr0.8I0.2 Heterojunction Photocatalyst: Synthesis and Visible-Light Degradation Mechanism of Rhodamine B

Authors: LI Dongmei, HE Shuai, JIANG Shuxian, CHEN Zhixiang, WU Hanjie, ZHANG Jinming, DAI Ziqiang, LIU Ziye

A novel S-scheme heterojunction photocatalyst, Bi6O5(OH)3(NO3)5·3H2O/BiOBr0.8I0.2 (BON@BI), was synthesized via a one-step hydrothermal method using Bi6O5(OH)3(NO3)5·3H2O (BON), KBr, and KI as precursors. The mass ratio of BON to BiOBr0.8I0.2 (BI) was optimized, revealing that the 20% BON@BI composite (BON@BIOPT) exhibited the highest visible-light photocatalytic activity. Under 30 min of visible-light irradiation, BON@BIOPT achieved a 99.8% degradation efficiency of Rhodamine B (RhB), approximately twice that of pristine BI (52.2%). The composite displayed a rod-like morphology with uniform nanosheets, and its specific surface area increased from 32.54 m²·g⁻¹ (BI) to 44.7 m²·g⁻¹. The absorption edge red-shifted from 560 nm (BI) to 580 nm, narrowing the bandgap from 2.55 eV to 2.43 eV. The S-scheme heterojunction formed between BON and BI generates an internal electric field that effectively suppresses recombination of strongly reducing photogenerated electrons and strongly oxidizing holes, with superoxide radicals (O₂•⁻) and holes (h⁺) identified as the primary reactive species. BON@BIOPT exhibited excellent stability, retaining 88.6% degradation efficiency after seven consecutive cycles. It also demonstrated robust environmental adaptability, maintaining 85–98% degradation efficiency under various pH conditions and in the presence of interfering anions. The degradation pathway of RhB involves N-de-ethylation, cleavage of the conjugated chromophore, and deamination, ultimately mineralizing into low-molecular-weight organics, inorganic salts, CO₂, and H₂O. These results underscore the potential of BON@BIOPT for practical remediation of organic pollutants in water.

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S-scheme Bi6O5(OH)3(NO3)5·3H2O/BiOBr0.8I0.2 Heterojunction Photocatalyst: Synthesis and Visible-Light Degradation Mechanism of Rhodamine B

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511046• Jan 15, 2026

Comparative Carbon Footprint of Ex-situ Remediation Facility and On-site Remediation Modes for Contaminated Soil

Authors: LI De'an, DENG Yirong, LI Fuhan, ZHANG Zhenxing, LI Shuo, WANG Jun

To evaluate the carbon footprint differences between the emerging ex-situ remediation facility mode and the conventional on-site remediation mode in China, this study employed the SEFA tool to calculate greenhouse gas (GHG) emissions and energy consumption for four typical remediation scenarios. Results indicate that the carbon emission intensity of solidification/stabilization (S/S) in the remediation facility is 12.00% higher than that of on-site S/S, with unit carbon intensities of 66.74 and 59.59 kgCO2e·m−3, respectively, and total energy consumption 11.90% higher. The soil transport segment in the facility S/S contributes 13% of carbon emissions, being the primary reason for its higher total carbon footprint. Conversely, thermal desorption (TD) in the facility exhibits 11.10% lower carbon emissions than on-site TD, with unit intensities of 269.16 and 302.78 kgCO2e·m−3, and total energy consumption 3.97% lower, mainly due to the utilization of landfill biogas as renewable energy for heat and power generation, while soil transport contributes only 3% of emissions. The reagent segment in S/S and the heat supply segment in TD account for 77%–86% and 70%–72% of total GHG emissions, respectively. The study demonstrates that remediation facilities, leveraging advantages such as landfill biogas, can actively aggregate contaminated soil from surrounding areas for centralized thermal desorption, which is beneficial for regional carbon emission reduction in soil remediation.

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Comparative Carbon Footprint of Ex-situ Remediation Facility and On-site Remediation Modes for Contaminated Soil

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202510017• Jan 15, 2026

Carbon Emission Analysis and Reduction Scenario Prediction of Municipal Solid Waste Based on LCA-SD Model

Authors: ZHAO Hui, LIN Xiaoying, JIANG Wei, HUANG Hanwei, CAO Xinchong, CHEN Junjun, LIU Xueping

Municipal solid waste (MSW) is a significant source of urban carbon emissions. This study integrates life cycle assessment (LCA) and system dynamics (SD) to construct a multi-subsystem LCA-SD model covering economy, population, waste generation, transportation, treatment, and resource utilization, using Fuzhou City as a case study. The model was validated against historical data and uncertainty analysis. Carbon emissions from MSW transportation, treatment, and resource utilization during 2013–2023 were calculated, and emission trends under seven reduction scenarios for 2024–2035 were predicted. Results show that Fuzhou's MSW treatment evolved through three stages: 'landfill+incineration', 'treatment structure adjustment', and 'incineration+kitchen waste resource utilization', corresponding to emission growth, fluctuation, and reduction periods. In 2023, total net carbon emissions were 1.07×10^6 t CO2-eq, with incineration being the largest contributor (9.93×10^5 t), followed by transportation (2.93×10^4 t), leachate treatment (2.14×10^4 t), and kitchen waste treatment (7.90×10^3 t, negative emission). Scenario analysis indicates that without further measures, carbon neutrality cannot be achieved. Synergistic enhancement of kitchen waste separation and incineration power generation efficiency can significantly boost reduction, potentially achieving carbon neutrality by 2032. The study provides a dynamic accounting and scenario assessment framework for low-carbon transition of urban solid waste systems.

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Carbon Emission Analysis and Reduction Scenario Prediction of Municipal Solid Waste Based on LCA-SD Model

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202512066• Jan 15, 2026

RuO2 Nanorods for Electrochemical Chlorine Evolution and Simultaneous Removal of Ammonia Nitrogen and COD from Wastewater

Authors: SONG Xiaoyang, WANG Yan, REN Xiaohua, ZHAO Xu

This study addresses the removal of ammonia nitrogen (NH4+-N) and chemical oxygen demand (COD) from real coal chemical wastewater via electrochemical chlorine evolution. A nanorod-structured ruthenium dioxide catalyst (N-RuO2) was synthesized by modifying ruthenium trichloride precursor with ammonium chloride. Compared with unmodified RuO2, commercial DSA, and commercial RuO2 (Com-RuO2), N-RuO2 exhibited significantly enhanced electrochemical performance: Faradaic efficiency for chlorine evolution increased by 12.9%, 18.5%, and 25.6%, respectively; accelerated lifetime improved by 1.7, 1.9, and 2.9 times, respectively. In treating real coal chemical wastewater, N-RuO2 reduced NH4+-N to 86.4 mg·L−1 and COD to 72 mg·L−1, with degradation rate constants approximately 2.08 and 1.46 times higher than Com-RuO2, while energy consumption decreased by 17.7 Wh·g−1 and 1.5 Wh·g−1, respectively. Further studies showed that increasing chloride ion concentration enhanced removal rates and reduced energy consumption; higher current density accelerated removal but increased energy use; alkaline conditions favored NH4+-N removal, while neutral conditions favored COD removal. The excellent electrochemical performance of RuO2 nanorods indicates broad application prospects in practical water treatment.

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202408057• Jan 15, 2026

Coastal Urban Waterlogging Simulation and Drainage System Optimization: A Case Study of the Shajing River Drainage Area in Shenzhen

Authors: YU Ziwei, LYU Jiajie, TIAN Zhan, YE Qinghua, WANG Yanlong, LIU Qiaodan, TANG Yingdong

Urban waterlogging, exacerbated by climate change and rapid urbanization, poses increasing risks, particularly in coastal low-lying areas with dense river networks. This study simulated waterlogging in the Shajing River drainage area of the Maozhou River basin, Shenzhen, using the SOBEK hydrodynamic model. Under a 5-year return period rainfall, 47 manholes overflowed and 31.29% of stormwater pipes operated at full capacity. Twelve waterlogging-prone points were identified: eight due to insufficient drainage capacity and five due to river backflow from low elevation. Two optimization schemes were compared: enlarging pipe diameters and implementing Low Impact Development (LID) measures. Pipe enlargement reduced overflowing manholes by 32 and full-flow pipe length by 20%, effectively decreasing surface ponding. LID measures reduced overflowing manholes by only 4 and full-flow pipe length by 1.5%, but decreased maximum flooding depth by nearly 1 m, alleviating drainage system burden. The study highlights the complex causes of coastal urban waterlogging, especially river backflow under tidal influence, and recommends considering sea-level rise and storm surge in drainage design. The findings provide valuable references for attributing waterlogging causes and planning drainage network upgrades in coastal cities.

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Coastal Urban Waterlogging Simulation and Drainage System Optimization: A Case Study of the Shajing River Drainage Area in Shenzhen

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511011• Jan 15, 2026

Continuous Manufacturing Process Design of Solid-Waste-Based Ozone Catalysts and Their Long-Term Performance Study

Authors: HUANG Yanli, LI Yanhong, JI Zehua, et al.

The high cost of catalysts is a critical barrier to the upgrading and cost reduction of catalytic ozonation technology. This study developed a low-cost, long-life Fe–Mn-based ozone catalyst (FMG) derived from solid wastes (red mud and blast-furnace slag), leveraging iron and manganese components to construct dual active centers. A continuous manufacturing process was achieved by integrating alkali-activated cementitious reactions with disc pelletization via a cascade spray-coating and multi-stage curing technique. Under optimal conditions (ozone dosage 3.5 mg·L−1), the catalyst achieved 81.81% total organic carbon (TOC) removal of phenol solution within 60 min, retaining 87.27% of its initial activity after 15 reuse cycles. Long-term continuous-flow tests over 60 days demonstrated stable TOC removal between 69.44% and 75.46%. The production cost of FMG was 1,351.44 CNY·t−1, and the unit TOC removal cost was only 0.06 CNY·(g TOC)−1, representing a 78.69%–86.85% reduction compared to commercial catalysts (0.30–0.48 CNY·(g TOC)−1). This work provides a theoretical and technical foundation for cost-effective catalytic ozonation and high-value conversion of bulk solid wastes.

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Continuous Manufacturing Process Design of Solid-Waste-Based Ozone Catalysts and Their Long-Term Performance Study

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511050• Jan 15, 2026

Engineering Optimization of an 80 t·d−1 Municipal Solid Waste Gasification-Incineration Furnace: A Case Study in Inner Mongolia

Authors: ZHANG Zhefeng, LI Wenkai, GU Qi, LIU Jianguo, SHI Lin, ZHANG Jialong, WANG Qunhui, MA Lisha, ZHENG Tianlong

Municipal solid waste (MSW) management in Inner Mongolia has long relied on landfilling, facing land scarcity and leachate management challenges. This study addresses the region's dry, cold climate, high proportion of agricultural and livestock waste, fluctuating moisture content, and weak leachate treatment capacity. An engineering optimization was implemented on an 80 t·d−1 vertical rotary gasification-incineration system featuring a dual-combustion-chamber design (primary chamber for medium-temperature pyrolysis-gasification at 550–650 °C and secondary chamber for high-temperature oxidation above 900 °C), coupled with in-situ leachate recirculation. Field measurements showed improved processing capacity and continuous operation stability. Under the project's leachate yield, in-situ recirculation achieved on-site disposal without significant adverse effects on gasification-incineration conditions, providing buffering against moisture fluctuations. During the monitoring period, major gaseous pollutant emissions remained below current national standards. The results provide engineering references for the co-processing and stable operation of small-scale county-level MSW treatment facilities.

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Engineering Optimization of an 80 t·d−1 Municipal Solid Waste Gasification-Incineration Furnace: A Case Study in Inner Mongolia

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511094• Jan 15, 2026

Effect of Fermentation Temperature on Volatile Fatty Acid Production and Fungal Community Structure from Brewer's Spent Grain

Authors: HONG Wenfei, XU Yufeng, TONG Juan, WEI Yuansong, CHEN Hexiang

Brewer's spent grain (BSG), a major byproduct of the brewing industry, is produced in large quantities globally, yet its high-value utilization remains limited. This study investigated the effects of fermentation temperature (35, 40, 45, 50, and 55 °C) on volatile fatty acid (VFA) production and fungal community structure during anaerobic fermentation of BSG. Results showed that mesophilic temperatures significantly enhanced VFA yields, with the highest production at 35 °C, reaching 344.22 mg/g COD converted, and a peak VFA concentration of 14,267 mg/L after 5 days. Acetic acid dominated the VFA profile (95.6%–98.9%) across all temperatures. Protein and carbohydrate degradation rates were highest under mesophilic conditions, while lipid degradation peaked at 55 °C. Fungal community analysis revealed that at peak acid production, cellulose-degrading fungi were predominant, with Oligophagozyma being the dominant genus at 35 °C (90.07%) and 40 °C (55.31%). Higher temperatures increased fungal diversity and evenness. Mantel tests indicated that carbohydrates and lipids promoted fungal growth, whereas total dissolved solids, nitrate, and phosphate inhibited it. These findings provide insights into the role of fungi in VFA production from BSG and support its resource utilization.

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Effect of Fermentation Temperature on Volatile Fatty Acid Production and Fungal Community Structure from Brewer's Spent Grain

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511052• Jan 15, 2026

Effects of Different Morphologies of PET Microplastics on Anaerobic Digestion of Sewage Sludge

Authors: MA Yuhui, XIA Ziyuan, GOU Min, TANG Yueqin

Microplastics in sewage sludge, owing to their diverse physicochemical properties, can differentially affect subsequent anaerobic digestion. This study focused on polyethylene terephthalate (PET) microplastics, systematically investigating the effects of particle (MP), fiber (MF), and film (MPF) morphologies at concentrations of 0–150 mg·g⁻¹ (based on total solids) on sludge digestion performance and microbial community structure. Results showed that MP inhibited total biogas production at all concentrations (inhibition rates 8.16%–9.58%), whereas MF and MPF exhibited low-concentration stimulation and high-concentration inhibition, with MPF exerting stronger inhibition than MF. All MP concentrations induced significant reactive oxygen species (ROS) accumulation (increases of 9.43%–34.52%), indicating the strongest oxidative stress. Low concentrations of PET generally enhanced cell membrane permeability, prompting microbes to secrete different extracellular polymeric substances (EPS) to resist stress. The morphology and concentration of microplastics regulated the relative abundances of key functional bacteria (e.g., proteolytic bacteria and organic acid-oxidizing bacteria) and low-abundance bacteria, ultimately leading to differences in digestion performance. This study provides a theoretical basis for efficient treatment of sludge containing microplastics.

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Effects of Different Morphologies of PET Microplastics on Anaerobic Digestion of Sewage Sludge

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Original ResearchVol. 20, Issue 7 • pp. 100-112DOI: 10.12030/j.cjee.202511062• Jan 15, 2026

Application and Mechanistic Study of Lactate Regulation and Microbial Immobilization Technology in Sediment Microbial Fuel Cell Systems

Authors: YU Jianjun, QI Jiarui, WU Yutiancheng, LI Xiaofeng, XIE Wen, WU Chenyang

Sediment microbial fuel cells (SMFCs) are a green technology for simultaneous polluted sediment remediation and energy recovery, yet their performance is constrained by insufficient anodic microbial activity and low electron transfer efficiency. This study employed lactate addition combined with composite engineered microbial immobilization to synergistically optimize SMFC performance by enhancing microbial stability and carbon source supply. Results showed that lactate, as an easily utilized electron donor, promoted electrochemical activity, achieving a maximum power density of 22.06 mW·m−2 at 6 mmol·L−1, a 194% improvement over the blank group. Immobilization further enhanced electron transfer efficiency, with the highest output voltage (88.75 mV) being 2.09 times that of the non-immobilized group. For pollutant degradation, the 6 mmol·L−1 lactate group achieved TOC and TN removal rates of 29.02% and 28.4%, respectively, outperforming the control (22.41% and 21.42%). However, high lactate concentrations inhibited microbial metabolism, leading to TOC accumulation. 16S rRNA analysis revealed that the anodic microbial community was dominated by Bacillota and Pseudomonadota, both possessing electroactive and pollutant-degrading capabilities, indicating that lactate and immobilization exert a synergistic effect in SMFCs, simultaneously enhancing electricity generation and pollutant removal efficiency.

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Application and Mechanistic Study of Lactate Regulation and Microbial Immobilization Technology in Sediment Microbial Fuel Cell Systems

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