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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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