Key Takeaways & Executive Findings
- •• • Combined algicide + submerged plant treatments significantly reduced TN, TP, Chl-a, and turbidity, achieving superior eutrophication control compared to plant-only treatments within the experimental period. • • The algicide + V. natans combination yielded the most pronounced reduction in the comprehensive trophic state index, indicating optimal restoration efficacy for this species pairing. • • Compound algicide significantly increased V. natans growth rate and H. verticillata catalase (CAT) activity, demonstrating species-specific physiological responses and suggesting V. natans has higher adaptability to the algicide. • • The compound algicide formulation (PQGA-126, PAC, red soil) effectively removed algae and reduced turbidity, providing a low-cost, high-efficiency option for emergency bloom control and eutrophic water remediation.
Abstract
Eutrophication and cyanobacterial blooms threaten aquatic ecosystems and drinking water safety globally. This study evaluated the efficacy of a compound algicide (PQGA-126, PAC, and red soil) combined with submerged plants (Vallisneria natans and Hydrilla verticillata) for suppressing blooms and restoring eutrophic water. Indoor static experiments used algae-laden water from Nanhu Lake, Gongqingcheng, Jiangxi. Six treatments were established: control, V. natans alone, H. verticillata alone, algicide alone, algicide + V. natans, and algicide + H. verticillata. Results demonstrated that combined treatments significantly reduced total nitrogen (TN), total phosphorus (TP), chlorophyll-a (Chl-a), and turbidity, markedly lowering eutrophication within a short period. The combined approach outperformed single-plant treatments, with algicide + V. natans achieving the greatest reduction in the comprehensive trophic state index. Additionally, the algicide significantly enhanced V. natans growth rate and H. verticillata catalase (CAT) activity, indicating species-specific physiological responses. These findings suggest that integrating compound algicide with submerged plants, particularly V. natans, offers a promising strategy for rapid and effective eutrophic water remediation.
1. Introduction
Excessive nutrient loading into freshwater systems accelerates eutrophication, triggering frequent cyanobacterial blooms that compromise ecological integrity and drinking water safety. Conventional chemical algicides such as copper sulfate are effective but pose toxicity risks to non-target organisms. Inorganic flocculants like polyaluminum chloride (PAC) and polyferric sulfate (PFAS) can aggregate and settle algae at low cost, yet their performance is pH-dependent and inadequate for organic-polluted waters. These limitations underscore the need for algicides with reduced side effects, stable performance, and broad applicability.
This study addresses this bottleneck by developing a composite algicide combining PQGA-126 (a quaternary ammonium polymer), PAC, and red soil. The formulation leverages synergistic flocculation and charge neutralization to enhance algae removal and turbidity reduction. To achieve sustained restoration, the algicide was integrated with submerged plants—Vallisneria natans and Hydrilla verticillata—which stabilize sediments and assimilate nutrients. Indoor static experiments evaluated the combined efficacy on eutrophic water from Nanhu Lake, providing empirical evidence for an integrated emergency and long-term remediation strategy.
Loading authentic research manuscript (Pages 1–5)...
LI Xiaozhen, LI Wei, HUO Bintang, SHENG Weijing, DAI Taotao, ZHONG Jiayou, DAI Guofei, CHEN Yuwei (2026). Combined Application of Compound Algicide and Submerged Plants for Algal Bloom Control and Eutrophic Water Remediation. Journal of Environmental Engineering Technology. https://doi.org/10.13205/j.hjgc.202608013
Research & Educational Purpose Only: The translations, structured abstracts, analytical annotations, and data reports provided by SinoGreenTechare intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoGreenTech claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What are the specific mechanisms by which the compound algicide (PQGA-126, PAC, red soil) enhances algae removal compared to PAC alone?
The composite algicide synergistically combines the cationic polymer PQGA-126 with PAC and red soil. PQGA-126 provides strong charge neutralization and bridging flocculation, while PAC offers coagulation and red soil acts as a weighting agent to accelerate settling. This multi-mechanism approach improves floc formation and settling efficiency, achieving superior turbidity and Chl-a reduction compared to PAC alone, as evidenced by the significant decreases in TN, TP, Chl-a, and turbidity in combined treatments.
How does the combined application of algicide and submerged plants affect the physiological stress responses of V. natans and H. verticillata?
The algicide significantly increased the growth rate of V. natans and catalase (CAT) activity in H. verticillata. This indicates that V. natans exhibited higher adaptability, likely due to enhanced antioxidant defense or metabolic resilience. The differential response suggests species-specific tolerance, which is critical for selecting appropriate plant species in integrated remediation strategies.
What are the scalability and cost implications of using this compound algicide for large-scale eutrophic lake restoration?
The components—PQGA-126, PAC, and red soil—are commercially available and relatively inexpensive. Red soil is abundant and low-cost, while PAC is widely used in water treatment. The combined approach reduces the required dosage of synthetic polymers, potentially lowering overall costs. However, scalability depends on factors such as mixing efficiency, application method, and environmental conditions. Pilot-scale trials are necessary to optimize dosage and assess cost-effectiveness against conventional methods.
What is the long-term stability of the remediation effect, and are there potential risks of secondary pollution from the algicide residues?
The study focused on short-term effects (within the experimental period). Long-term stability requires monitoring nutrient rebound and plant establishment. The algicide components are generally considered low-toxicity; PAC is widely used in drinking water treatment, and PQGA-126 is a quaternary ammonium compound that may degrade. However, residual aluminum and polymer byproducts could pose risks. Further studies on degradation kinetics and ecotoxicological impacts are recommended to ensure environmental safety.
How does the performance of the combined algicide + V. natans treatment compare to other established remediation technologies, such as chemical precipitation or constructed wetlands?
The combined treatment achieved significant reductions in TN, TP, Chl-a, and turbidity within a short period, outperforming plant-only treatments. Compared to chemical precipitation alone, the integration with submerged plants provides additional ecological benefits such as habitat provision and nutrient cycling. Constructed wetlands offer long-term nutrient removal but require larger footprints and longer retention times. The combined approach offers a rapid response option for emergency bloom control while initiating ecological restoration, making it a versatile tool for eutrophic water management.
Related Chinese Research & Cross-Citations
Synergistic Regulation by Long- and Short-Chain Quorum Sensing Signaling Molecules Enhances Sulfamethoxazole Metabolism in Electroactive Biofilms within a Microbial Electrolysis Cell Coupled Anaerobic Digestion System
High-strength sulfamethoxazole (SMX) wastewater severely inhibits anaerobic microorganisms, reducing organic degradation and methane yield. This study investigated the effects of short-chain (C6-HSL) and long-chain (C12-HSL) N-acyl-homoserine lactone (AHL) signaling molecules, individually and in combination, on the construction, performance, and antibiotic resistance gene (ARG) profiles of anaerobic electroactive biofilms within a microbial electrolysis cell coupled anaerobic digestion (MEC-AD) system. Compared to the control (no AHLs), SMX removal efficiency increased by 9.26%, 7.44%, and 10.67% for C6-HSL (T1), C12-HSL (T2), and combined (T3) treatments, respectively. Methane production rates rose by 20.4%, 16.9%, and 23.1% for T1, T2, and T3, respectively. AHLs promoted extracellular polymeric substance secretion, enhancing electroactive microbe attachment to the anode. Microbial community analysis revealed increased diversity and modulated key functional genera. Notably, Georgenia abundance increased by 16.77% (T1) and 36.47% (T3) but decreased by 15.99% (T2). ARG analysis showed that single AHLs elevated intI1, sul1, and sul2 abundances, whereas combined AHLs (T3) exhibited a milder response, with sul2 abundance reduced by 4.92% relative to control. This suggests synergistic AHLs suppress ARG host proliferation. This study first demonstrates that combined short- and long-chain AHLs enhance electroactive biofilm formation, maintain microbial community stability, and modulate ARG dissemination risk, offering a quorum sensing-based strategy for antibiotic wastewater treatment and risk management.
Preparation of Solid-Phase Carbon Sources with Different Ratios and Their Carbon Release Properties
Low C/N ratios in wastewater treatment plant effluent necessitate external carbon sources for denitrification, but conventional liquid carbon sources are costly and unstable. This study prepared nine composite solid-phase carbon sources by combining PHBV with natural cellulose materials (straw, sawdust, corncob) at different mass ratios. Dynamic release experiments, DOC analysis, UV-Vis spectroscopy, and EEM fluorescence were employed to characterize carbon release. Results showed that increasing cellulose proportion in corncob-based sources led to release patterns opposite to those of straw- and sawdust-based sources. For straw and sawdust, higher cellulose ratios accelerated release rates, increased total release and duration, reduced aromaticity and molecular weight of released DOM, and promoted protein-like components (tryptophan, tyrosine), indicating enhanced bioavailability. Under identical ratios, corncob-based sources exhibited moderate total release, release durations exceeding 134 h, lower DOM aromaticity and molecular weight, and lower humic substance proportion, indicating superior bioavailability and engineering potential. Among the nine sources, JG5, MX5, and CC4 (PHBV:cellulose mass ratios of 4:5, 4:5, and 1:1, respectively) showed optimal comprehensive performance with low theoretical maximum release, long release periods, and high mass transfer coefficients. EEM-PARAFAC identified three DOM components (protein-like C1, C2; humic-like C3), with protein-like components dominating. This study validates the relationship between cellulose proportion and release kinetics and reveals synergistic regulation of DOM components, offering guidance for designing effective solid-phase carbon sources.
Enhancement of Anaerobic Digestion Operational Efficiency for Guar Gum Production Wastewater Using a Microaerobic-Biochar Coupled System
Guar gum production wastewater contains 1,2-propanediol, which in conventional anaerobic treatment causes propionate accumulation and microbial inhibition. Microaerobic conditions foster fermentative bacterial metabolism, enhancing organic substrate conversion, while biochar promotes anaerobic microbial aggregation and oxygen tolerance. This study treated actual guar gum wastewater using three configurations: blank control, anaerobic, and microaerobic-biochar (O2/BC) coupled systems. Under mesophilic conditions (37 °C), with micro-aeration at 0.2 mL/(g VS·d) and biochar dosage of 15 g/L, the O2/BC system achieved a COD removal efficiency of 90%, 10.6 percentage points higher than the anaerobic control. Effluent COD and propionate concentrations dropped to 3800 mg/L and 0.15 g/L, respectively, representing reductions of 49.6% and 98.4% versus the control. Biogas production was 1.64 times that of the control, with a maximum methane concentration of 77.2%. Fourier transform infrared spectroscopy (FT-IR) indicated increased abundance of –OH, –CH2–, and C–O functional groups on sludge surfaces, revealing biochar's adsorption enhancement. Scanning electron microscopy (SEM) showed dense microbial aggregates dominated by long bacilli, distinct from conventional anaerobic sludge. Microbial community analysis revealed increased abundance of Clostridium and Comamonas, modulating the propionate-to-acetate ratio and optimizing acidification efficiency, thereby promoting complex organic degradation. This study provides a novel technical pathway for biological treatment of alcohol-rich organic wastewater.
Occurrence Characteristics, Source Apportionment, and Ecological Risk Assessment of Pesticides in Plateau Lakes: A Case Study of Dianchi Lake
This study systematically investigated the occurrence, spatial distribution, sources, and ecological risks of 160 pesticides in Dianchi Lake, a typical plateau lake impacted by agricultural activities. A total of 37 pesticides were detected in the water, with total concentrations ranging from 64.2 to 1132.8 ng/L (average 610.0 ng/L). Fungicides, including boscalid (BOS), fluopicolide (FPC), and dimethomorph (DMM), were dominant, contributing up to 65.0% of the total concentration. Spatially, the southern lake region exhibited significantly higher concentrations (672.5 ng/L) than the north, attributed to intensive facility agriculture. Highly hydrophobic pesticides, such as penconazole (PEN), showed a tendency to enrich in bottom layers. Source apportionment identified inflowing rivers and wastewater treatment plant effluents as primary input sources, with average concentrations 7 and 9 times higher than lake water, respectively. Ecological risk assessment revealed that pesticides posed the highest risk to algae, followed by daphnia and fish. Prometryn (PMT) was identified as a high-risk factor for algae, while profenofos (PFF) and carbendazim (CBD) posed potential threats to higher trophic levels. These findings provide fundamental data and technical support for understanding pesticide pollution in plateau lake ecosystems.
Microbiome Mechanisms of Composite Carbon Sources for Enhancing Denitrification and Reducing N2O Emissions
Biological nitrogen removal in wastewater treatment plants (WWTPs) is often limited by insufficient influent carbon sources, necessitating external carbon addition to enhance denitrification. Conventional single carbon sources, such as sodium acetate, frequently fail to meet the metabolic demands of complex microbial communities, compromising nitrogen removal efficiency and stability. Composite carbon sources, by providing multiple electron donors, can improve metabolic cooperation among microorganisms, yet their underlying microbial mechanisms remain insufficiently understood. In this study, activated sludge from a municipal WWTP was used to investigate the microbial mechanisms of composite carbon sources during denitrification. Batch denitrification experiments were conducted in combination with metagenomic and metatranscriptomic analyses to systematically characterize microbial community structure and functional gene expression under different carbon source conditions. Results showed that, compared with sodium acetate as the single carbon source, the composite carbon source system (sodium acetate: sodium succinate: ethanol = 2:1:3) increased the denitrification rate from (6.822 ± 0.141) mg/(L·h) to (8.370 ± 0.186) mg/(L·h), representing a 22.7% improvement, while reducing N2O accumulation by approximately 55%. Metagenomic analysis revealed that Ottowia, Rubrivivax, Thauera, and Zoogloea were the dominant denitrifying genera. Metatranscriptomic results further demonstrated that the composite carbon sources significantly upregulated the transcription of key denitrification genes, with nirS, norB, and nosZ increasing by 37.8%, 27.4%, and 48.6%, respectively. In addition, the composite carbon sources promoted complementary carbon metabolic strategies among different microbial communities, enhancing electron donor supply and improving denitrification efficiency. These findings indicate that composite carbon sources synergistically enhance denitrification performance through regulation of functional gene transcription in complex microbial communities, providing a theoretical basis for carbon source optimization in WWTPs.
Key Environmental Behaviors and Pollution Control Strategies of Tire Wear Particles in Aquatic Environments
Tire wear particles (TWPs) are emerging pollutants and constitute the dominant type of microplastics (MPs) in urban stormwater runoff, accounting for up to 90% of MPs in some cases. They are characterized by small size, high mobility, complex composition, and significant toxicity. Current research on TWPs remains fragmented, lacking a comprehensive understanding of their environmental behaviors and pollution control in aquatic systems. This review systematically analyzes the enrichment and vectoring roles of TWPs for coexisting pollutants, and their environmental fate, including ecotoxicological impacts, detection methodologies, release of intrinsic additives, and aggregation and sedimentation behaviors. Drawing on insights from other microplastic studies, the paper explores control technologies across the pollution pathway—source, transport, and terminal treatment—and proposes feasible management strategies. Key findings indicate that TWPs can adsorb heavy metals and organic contaminants, with adsorption capacities influenced by aging processes. Their aggregation is governed by solution chemistry, with critical coagulation concentrations varying with ionic strength and pH. The release of additives such as zinc and benzothiazoles is significant, posing ecological risks. Future research should focus on real-water aggregation mechanisms, additive release under natural conditions, long-term performance of treatment facilities like constructed wetlands under TWPs stress, enzymatic degradation pathways, and integration of AI, big data, and IoT for cost-effective detection and risk modeling. This review provides a scientific basis for developing targeted pollution control measures for TWPs in aquatic environments.