Login
Register
E-alert
Current Articles
2026, Volume 44, Issue 3
Display Method:
2026,
44(3):
1-10.
doi: 10.13205/j.hjgc.202603001
Abstract:
This study reconceptualized partial nitrification from a microbial ecological perspective by elucidating the dynamic competition between AOB and NOB across the initiation， maintenance， and destabilization phases. Continuous selection pressure was proposed as the core determinant of process stability within a community-process coupled framework. The review indicates that the initiation depends on non-steady-state disturbances that amplify AOB growth advantages， whereas the maintenance phase is characterized by a metastable state with dynamic community structure but relatively stable function， where NOB persist at low abundance or under spatial constraint. When cumulative disturbances weaken AOB competitiveness， NOB can rapidly rebound， inducing a critical shift from partial to complete nitrification. Accordingly， operational strategies centered on resource supply， niche constraint， and community feedback are outlined， emphasizing window-period management to enhance system resilience. The alignment of time-resolved community data with key operational parameters is further discussed as a basis for identifying instability thresholds and early-warning signals to support predictive control and risk management in partial nitrification processes.
This study reconceptualized partial nitrification from a microbial ecological perspective by elucidating the dynamic competition between AOB and NOB across the initiation， maintenance， and destabilization phases. Continuous selection pressure was proposed as the core determinant of process stability within a community-process coupled framework. The review indicates that the initiation depends on non-steady-state disturbances that amplify AOB growth advantages， whereas the maintenance phase is characterized by a metastable state with dynamic community structure but relatively stable function， where NOB persist at low abundance or under spatial constraint. When cumulative disturbances weaken AOB competitiveness， NOB can rapidly rebound， inducing a critical shift from partial to complete nitrification. Accordingly， operational strategies centered on resource supply， niche constraint， and community feedback are outlined， emphasizing window-period management to enhance system resilience. The alignment of time-resolved community data with key operational parameters is further discussed as a basis for identifying instability thresholds and early-warning signals to support predictive control and risk management in partial nitrification processes.
2026,
44(3):
11-29.
doi: 10.13205/j.hjgc.202603002
Abstract:
Nitrogenous pollutant discharges are rising with urbanization and industrialization， and their untreated release worsens aquatic nitrogen pollution. Currently， nitrogen removal from municipal and industrial wastewater is transitioning from an energy-intensive model to strategies emphasizing pollution reduction， carbon mitigation， and synergistic efficiency. Green and sustainable nitrogen removal technologies represent a key research frontier in water pollution control. This review systematically examined nitrogen pollution in China's wastewater， characterized nitrogen-laden industrial effluents， and highlighted challenges such as wide concentration ranges， complex compositions， and treatment recalcitrance. Based on this analysis， this paper comprehensively reviewed the principles and applications of advanced nitrogen removal technologies， including physicochemical， biological， electrochemical/bioelectrochemical， and advanced oxidation processes. Their treatment efficiency， advantages， and limitations were analyzed， with special emphasis on the application of advanced oxidation processes for refractory nitrogenous pollutants. Future efforts should prioritize adopting low-energy， low-chemical-consumption biological nitrogen removal processes， integrate electrochemical and advanced oxidation processes with conventional methods， enhance overall treatment efficiency， and reduce costs. These advancements are pivotal for achieving China's Dual Carbon Goals and advancing sustainable development.
Nitrogenous pollutant discharges are rising with urbanization and industrialization， and their untreated release worsens aquatic nitrogen pollution. Currently， nitrogen removal from municipal and industrial wastewater is transitioning from an energy-intensive model to strategies emphasizing pollution reduction， carbon mitigation， and synergistic efficiency. Green and sustainable nitrogen removal technologies represent a key research frontier in water pollution control. This review systematically examined nitrogen pollution in China's wastewater， characterized nitrogen-laden industrial effluents， and highlighted challenges such as wide concentration ranges， complex compositions， and treatment recalcitrance. Based on this analysis， this paper comprehensively reviewed the principles and applications of advanced nitrogen removal technologies， including physicochemical， biological， electrochemical/bioelectrochemical， and advanced oxidation processes. Their treatment efficiency， advantages， and limitations were analyzed， with special emphasis on the application of advanced oxidation processes for refractory nitrogenous pollutants. Future efforts should prioritize adopting low-energy， low-chemical-consumption biological nitrogen removal processes， integrate electrochemical and advanced oxidation processes with conventional methods， enhance overall treatment efficiency， and reduce costs. These advancements are pivotal for achieving China's Dual Carbon Goals and advancing sustainable development.
2026,
44(3):
30-45.
doi: 10.13205/j.hjgc.202603003
Abstract:
Ozonation is an effective advanced treatment technology for textile dyeing and finishing wastewater； however， its large-scale application is primarily constrained by its intrinsically low ozone mass transfer efficiency. Membrane contactor reactors （MCRs） can significantly enhance ozone mass transfer by constructing microscale gas-liquid interfaces， offering advantages such as high mass transfer efficiency and the absence of secondary pollution. Nevertheless， issues including membrane fouling， high material costs， and poor operational stability still limit their engineering-scale implementation. This study systematically reviewed recent advances in the mechanisms of ozone mass transfer enhancement in MCRs. The principles of gas-liquid interfacial mass transfer and the design characteristics of hollow fiber membrane contactor configurations were introduced. The regulatory effects of membrane material properties （e.g.， the selection of hydrophobic PTFE/PVDF）， operating parameters （gas-liquid flow rates， transmembrane pressure， and pH）， and mass transfer models on the volumetric ozone mass transfer coefficient were critically analyzed. Furthermore， the application efficiency of MCRs in textile dyeing and finishing wastewater treatment was evaluated， with particular emphasis on efficient dye removal， organic matter mineralization， and decolorization. Research demonstrated that optimized MCR systems could increase the volumetric ozone mass transfer coefficient by 5~10 times compared with conventional bubble column processes， thereby substantially enhancing the kinetics of pollutant degradation. However， challenges such as membrane fouling-induced flux decline， bromate by-product formation， and cost-benefit optimization remained to be addressed. Finally， future research directions were proposed， focusing on the rational design of multifunctional composite membranes integrating antifouling properties， corrosion resistance， and low cost； the elucidation of interfacial reaction mechanisms through coupling with intensified fields such as high-gravity and electrocatalytic processes； the development of intelligent parameter regulation systems based on process modeling； and comprehensive techno-economic and environmental risk assessments at the pilot scale. These efforts will provide theoretical support and technical guidance for the engineering application of MCR-ozone processes.
Ozonation is an effective advanced treatment technology for textile dyeing and finishing wastewater； however， its large-scale application is primarily constrained by its intrinsically low ozone mass transfer efficiency. Membrane contactor reactors （MCRs） can significantly enhance ozone mass transfer by constructing microscale gas-liquid interfaces， offering advantages such as high mass transfer efficiency and the absence of secondary pollution. Nevertheless， issues including membrane fouling， high material costs， and poor operational stability still limit their engineering-scale implementation. This study systematically reviewed recent advances in the mechanisms of ozone mass transfer enhancement in MCRs. The principles of gas-liquid interfacial mass transfer and the design characteristics of hollow fiber membrane contactor configurations were introduced. The regulatory effects of membrane material properties （e.g.， the selection of hydrophobic PTFE/PVDF）， operating parameters （gas-liquid flow rates， transmembrane pressure， and pH）， and mass transfer models on the volumetric ozone mass transfer coefficient were critically analyzed. Furthermore， the application efficiency of MCRs in textile dyeing and finishing wastewater treatment was evaluated， with particular emphasis on efficient dye removal， organic matter mineralization， and decolorization. Research demonstrated that optimized MCR systems could increase the volumetric ozone mass transfer coefficient by 5~10 times compared with conventional bubble column processes， thereby substantially enhancing the kinetics of pollutant degradation. However， challenges such as membrane fouling-induced flux decline， bromate by-product formation， and cost-benefit optimization remained to be addressed. Finally， future research directions were proposed， focusing on the rational design of multifunctional composite membranes integrating antifouling properties， corrosion resistance， and low cost； the elucidation of interfacial reaction mechanisms through coupling with intensified fields such as high-gravity and electrocatalytic processes； the development of intelligent parameter regulation systems based on process modeling； and comprehensive techno-economic and environmental risk assessments at the pilot scale. These efforts will provide theoretical support and technical guidance for the engineering application of MCR-ozone processes.
2026,
44(3):
46-57.
doi: 10.13205/j.hjgc.202603004
Abstract:
Denitrification is a critical process for advanced nitrogen removal in wastewater treatment， fundamentally governed by microbially driven electron transfer and electron allocation. As research has shifted from macroscopic treatment metrics toward microscopic regulation， elucidating denitrification mechanisms from an electron-flow perspective has emerged as a major research frontier. This review systematically summarized the theoretical framework of electron flow in denitrification systems， compared intracellular electron transport pathways and energy allocation characteristics between heterotrophic and autotrophic denitrifiers， and highlighted the central role of the quinone pool in electron collection and redistribution. Furthermore， from the perspective of interspecies microbial interactions， recent advances in indirect interspecies electron transfer （IIET） and direct interspecies electron transfer （DIET） were summarized， and competitive as well as cooperative interactions among microorganisms in mixed systems during electron donor and electron acceptor utilization were analyzed. Building on this framework， the impacts of carbon source characteristics， pH， oxidation-reduction potential （ORP）， and coexisting contaminants on electron transport chains and electron allocation pathways were further discussed. Finally， in light of current limitations in the in situ quantification of electron fluxes， future research directions were proposed， including the development of multi-scale in situ characterization techniques， novel electron-conductive materials， and intelligent electron-flow regulation models.
Denitrification is a critical process for advanced nitrogen removal in wastewater treatment， fundamentally governed by microbially driven electron transfer and electron allocation. As research has shifted from macroscopic treatment metrics toward microscopic regulation， elucidating denitrification mechanisms from an electron-flow perspective has emerged as a major research frontier. This review systematically summarized the theoretical framework of electron flow in denitrification systems， compared intracellular electron transport pathways and energy allocation characteristics between heterotrophic and autotrophic denitrifiers， and highlighted the central role of the quinone pool in electron collection and redistribution. Furthermore， from the perspective of interspecies microbial interactions， recent advances in indirect interspecies electron transfer （IIET） and direct interspecies electron transfer （DIET） were summarized， and competitive as well as cooperative interactions among microorganisms in mixed systems during electron donor and electron acceptor utilization were analyzed. Building on this framework， the impacts of carbon source characteristics， pH， oxidation-reduction potential （ORP）， and coexisting contaminants on electron transport chains and electron allocation pathways were further discussed. Finally， in light of current limitations in the in situ quantification of electron fluxes， future research directions were proposed， including the development of multi-scale in situ characterization techniques， novel electron-conductive materials， and intelligent electron-flow regulation models.
2026,
44(3):
58-72.
doi: 10.13205/j.hjgc.202603005
Abstract:
Against the backdrop of increasingly severe global sustainability challenges， Bipolar Membrane Electrodialysis （BMED） technology is emerging as a pivotal solution driving transformation in the chemical， environmental， and resource management sectors. This technology not only demonstrates remarkable efficiency and economic benefits in critical areas such as resource extraction， pollution control， and CO2 capture but also exhibits substantial potential for large-scale commercial implementation. This review systematically outlines the working principles and fabrication methods of bipolar membranes， along with their applications across various industrial fields， highlighting their significant capacity to advance greener and more efficient industrial processes. Representative case studies in resource recovery， pollution mitigation， and CO2 capture are presented to illustrate the promising industrial prospects of BMED and validate its practical value in enabling sustainable resource utilization and environmental protection.
Against the backdrop of increasingly severe global sustainability challenges， Bipolar Membrane Electrodialysis （BMED） technology is emerging as a pivotal solution driving transformation in the chemical， environmental， and resource management sectors. This technology not only demonstrates remarkable efficiency and economic benefits in critical areas such as resource extraction， pollution control， and CO2 capture but also exhibits substantial potential for large-scale commercial implementation. This review systematically outlines the working principles and fabrication methods of bipolar membranes， along with their applications across various industrial fields， highlighting their significant capacity to advance greener and more efficient industrial processes. Representative case studies in resource recovery， pollution mitigation， and CO2 capture are presented to illustrate the promising industrial prospects of BMED and validate its practical value in enabling sustainable resource utilization and environmental protection.
2026,
44(3):
73-83.
doi: 10.13205/j.hjgc.202603006
Abstract:
Iron-dependent autotrophic denitrification （IDAD） is a promising biological technology for nitrogen removal from wastewater with a low C/N ratio. While significant differences in community structure among IDAD consortia from different studies have been reported， the underlying reasons remain unclear. Hypothesizing that the anion type of ferrous salts could be a key contributing factor， this study enriched two IDAD consortia （R1 and R2） using FeCl2 and FeSO4 as respective electron donors under identical inoculum sludge conditions. Their nitrogen removal performance， extracellular polymeric substance （EPS） composition， iron oxidation product properties， microbial community structure， and functional gene distribution characteristics during long-term operation were systematically compared. The results showed that R1 exhibited higher denitrification efficiency and Fe（Ⅱ） oxidation activity. Key iron-oxidizing bacterial genera such as Gallionella showed a significantly higher relative abundance in R1 than in R2， and R1 also maintained higher community diversity. Metagenomic analysis further revealed a higher abundance of functional genes related to iron oxidation and denitrification in R1. In contrast， R2 was enriched with more genera associated with sulfate metabolism and complex organic matter degradation. Distinct differences were also observed in EPS composition and iron mineral surface properties between the two consortia. This study confirms that the type of ferrous salt significantly regulates the structural assembly and metabolic functions of IDAD consortia， providing a theoretical basis for optimizing their application in practical wastewater treatment.
Iron-dependent autotrophic denitrification （IDAD） is a promising biological technology for nitrogen removal from wastewater with a low C/N ratio. While significant differences in community structure among IDAD consortia from different studies have been reported， the underlying reasons remain unclear. Hypothesizing that the anion type of ferrous salts could be a key contributing factor， this study enriched two IDAD consortia （R1 and R2） using FeCl2 and FeSO4 as respective electron donors under identical inoculum sludge conditions. Their nitrogen removal performance， extracellular polymeric substance （EPS） composition， iron oxidation product properties， microbial community structure， and functional gene distribution characteristics during long-term operation were systematically compared. The results showed that R1 exhibited higher denitrification efficiency and Fe（Ⅱ） oxidation activity. Key iron-oxidizing bacterial genera such as Gallionella showed a significantly higher relative abundance in R1 than in R2， and R1 also maintained higher community diversity. Metagenomic analysis further revealed a higher abundance of functional genes related to iron oxidation and denitrification in R1. In contrast， R2 was enriched with more genera associated with sulfate metabolism and complex organic matter degradation. Distinct differences were also observed in EPS composition and iron mineral surface properties between the two consortia. This study confirms that the type of ferrous salt significantly regulates the structural assembly and metabolic functions of IDAD consortia， providing a theoretical basis for optimizing their application in practical wastewater treatment.
2026,
44(3):
84-91.
doi: 10.13205/j.hjgc.202603007
Abstract:
This study took a large municipal wastewater treatment plant （WWTP） in northern China as the research object， and systematically investigated the influence characteristics and response mechanism of abnormal influent shock load on the structure of activated sludge microbial community. The results showed that influent shock caused drastic changes in the structure of activated sludge microbial community： the abundances of core functional flora such as Proteobacteria and Bacteroidetes decreased significantly by 55.30% and 44.35%， respectively； the community diversity was reduced， the nitrification function was weakened， and the concentration of effluent ammonia nitrogen increased. Meanwhile， shock-resistant flora such as the genus SJA-28 within Chlorobi proliferated rapidly， showing a 5.68-fold increase in relative abundance compared to the normal period， which helped sustain the pollutant removal capacity of the system to some extent. These findings confirmed that the activated sludge system has strong shock resistance and self-recovery capacity. The implementation of regulatory measures such as shortening sludge retention time （SRT） and increasing the dosage of sodium acetate and phosphorus removal chemicals was shown to be conducive to the rapid recovery of functional flora. Based on these findings， it is suggested that in practical operation， SRT adjustment strategies should be flexibly adjusted according to influent quality characteristics and temperature conditions， so as to improve the stability and resilience of the wastewater treatment system in responding to shock loading.
This study took a large municipal wastewater treatment plant （WWTP） in northern China as the research object， and systematically investigated the influence characteristics and response mechanism of abnormal influent shock load on the structure of activated sludge microbial community. The results showed that influent shock caused drastic changes in the structure of activated sludge microbial community： the abundances of core functional flora such as Proteobacteria and Bacteroidetes decreased significantly by 55.30% and 44.35%， respectively； the community diversity was reduced， the nitrification function was weakened， and the concentration of effluent ammonia nitrogen increased. Meanwhile， shock-resistant flora such as the genus SJA-28 within Chlorobi proliferated rapidly， showing a 5.68-fold increase in relative abundance compared to the normal period， which helped sustain the pollutant removal capacity of the system to some extent. These findings confirmed that the activated sludge system has strong shock resistance and self-recovery capacity. The implementation of regulatory measures such as shortening sludge retention time （SRT） and increasing the dosage of sodium acetate and phosphorus removal chemicals was shown to be conducive to the rapid recovery of functional flora. Based on these findings， it is suggested that in practical operation， SRT adjustment strategies should be flexibly adjusted according to influent quality characteristics and temperature conditions， so as to improve the stability and resilience of the wastewater treatment system in responding to shock loading.
2026,
44(3):
92-100.
doi: 10.13205/j.hjgc.202603008
Abstract:
This study， conducted at the Haikou Jiangdong Water Plant， applied a direct ultrafiltration process to treat the Nandu River water for potable use. Pilot-scale experiments were performed to optimize key operational parameters， including filtration cycle， backwash regime， and chemical-enhanced backwash （CEB） dosing and frequency. Under the optimized condition， the study comprehensively evaluated treatment performance， membrane-fouling characteristics， and techno-economic outcomes. The results showed that with a filtration cycle of 90 min and a high-intensity， short-duration backwash regime （170 L/（m2·h） flux， 150 s air scouring， 10 s combined air-water top backwash， 10 s combined air-water bottom backwash）， together with CEB using 500 mg/L sodium hypochlorite at a frequency of 7 days， the system exhibited robust adaptability and stable performance across varying raw-water qualities. The system maintained regulatory-compliant effluent even when raw-water CODMn reached 7.01 mg/L during high-turbidity periods （≥50 NTU）. However， when raw-water CODMn approached 3.6 mg/L during low-turbidity periods （<50 NTU）， there was a potential risk of the effluent CODMn exceeding the applicable drinking-water standard. Over 42 days of operation， the transmembrane pressure increased by a cumulative 8.48 kPa but stabilized following a short-term high-turbidity perturbation. Membrane-fouling analyses confirmed that the optimized operating conditions effectively limited fouling and identified siliceous-aluminous inorganic residues as the primary irreversible foulant fraction. A techno-economic assessment indicated water production costs of RMB 0.226/m3 （low-turbidity） and RMB 0.243/m3 （high-turbidity）， both lower than the RMB 0.261/m3 estimated for a conventional coagulation-sedimentation-filtration-disinfection process. The operational-parameter framework established in this study provides experimental evidence and technical support for applying direct ultrafiltration as a primary pretreatment unit in engineering practice.
This study， conducted at the Haikou Jiangdong Water Plant， applied a direct ultrafiltration process to treat the Nandu River water for potable use. Pilot-scale experiments were performed to optimize key operational parameters， including filtration cycle， backwash regime， and chemical-enhanced backwash （CEB） dosing and frequency. Under the optimized condition， the study comprehensively evaluated treatment performance， membrane-fouling characteristics， and techno-economic outcomes. The results showed that with a filtration cycle of 90 min and a high-intensity， short-duration backwash regime （170 L/（m2·h） flux， 150 s air scouring， 10 s combined air-water top backwash， 10 s combined air-water bottom backwash）， together with CEB using 500 mg/L sodium hypochlorite at a frequency of 7 days， the system exhibited robust adaptability and stable performance across varying raw-water qualities. The system maintained regulatory-compliant effluent even when raw-water CODMn reached 7.01 mg/L during high-turbidity periods （≥50 NTU）. However， when raw-water CODMn approached 3.6 mg/L during low-turbidity periods （<50 NTU）， there was a potential risk of the effluent CODMn exceeding the applicable drinking-water standard. Over 42 days of operation， the transmembrane pressure increased by a cumulative 8.48 kPa but stabilized following a short-term high-turbidity perturbation. Membrane-fouling analyses confirmed that the optimized operating conditions effectively limited fouling and identified siliceous-aluminous inorganic residues as the primary irreversible foulant fraction. A techno-economic assessment indicated water production costs of RMB 0.226/m3 （low-turbidity） and RMB 0.243/m3 （high-turbidity）， both lower than the RMB 0.261/m3 estimated for a conventional coagulation-sedimentation-filtration-disinfection process. The operational-parameter framework established in this study provides experimental evidence and technical support for applying direct ultrafiltration as a primary pretreatment unit in engineering practice.
2026,
44(3):
101-111.
doi: 10.13205/j.hjgc.202603009
Abstract:
In the context of global carbon neutrality goals and energy transformation，it is urgent to develop new technologies that efficiently convert CO2 into renewable energy carriers such as CH4. Microbial electrolysis cells （MECs）， which couple electrochemistry with microbial metabolism for CO2 conversion， exhibit performance that is heavily dependent on the electron transfer capabilities and biocompatibility of the cathode.Therefore，Nafion was employed to load nanoscale Fe3O4 and carboxylated multi-walled carbon nanotubes onto nickel foam （NF）. The electrochemical performance of the modified NF was characterized using techniques such as electrochemical impedance spectroscopy （EIS），cyclic voltammetry （CV），and linear sweep voltammetry （LSV）. The results indicated that the modified NF exhibited lower internal resistance，a larger electrochemical active surface area，and enhanced hydrogen evolution capabilities.Ultimately，this modified cathode was employed in a constant current dual-chamber anaerobic methanogenic MECs for the electrochemical reduction of CO2 to CH4.The results demonstrated that under a constant current of -0.1 A，the CH4 concentration of the nanoscale Fe3O4 and carboxylated multi-walled carbon nanotube-modified NF group could reach 90%，surpassing the 80% CH4 concentration of the NF group. Moreover，the daily CH4 production of the modified group was 295 mL，higher than the 260 mL daily methane production of the NF group，reflecting an increase of 13%. It was found that the modified NF exhibited higher hydrogen production and lower internal resistance， creating a more favorable environment for the growth and enrichment of hydrogenotrophic methanogens， thereby facilitating the electrochemical reduction of CO2 to CH4. Subsequent microbial community analysis also indicated that the relative abundance of the hydrogenotrophic methanogen Methanobacterium in the reactor with the modified NF was higher than that in the NF group，further facilitating the process of H2 serving as an electron donor for CO2 reduction to CH4. This research provides new ideas and experimental evidence for the development of novel non-precious metal composite cathode materials in bioelectrochemical systems.
In the context of global carbon neutrality goals and energy transformation，it is urgent to develop new technologies that efficiently convert CO2 into renewable energy carriers such as CH4. Microbial electrolysis cells （MECs）， which couple electrochemistry with microbial metabolism for CO2 conversion， exhibit performance that is heavily dependent on the electron transfer capabilities and biocompatibility of the cathode.Therefore，Nafion was employed to load nanoscale Fe3O4 and carboxylated multi-walled carbon nanotubes onto nickel foam （NF）. The electrochemical performance of the modified NF was characterized using techniques such as electrochemical impedance spectroscopy （EIS），cyclic voltammetry （CV），and linear sweep voltammetry （LSV）. The results indicated that the modified NF exhibited lower internal resistance，a larger electrochemical active surface area，and enhanced hydrogen evolution capabilities.Ultimately，this modified cathode was employed in a constant current dual-chamber anaerobic methanogenic MECs for the electrochemical reduction of CO2 to CH4.The results demonstrated that under a constant current of -0.1 A，the CH4 concentration of the nanoscale Fe3O4 and carboxylated multi-walled carbon nanotube-modified NF group could reach 90%，surpassing the 80% CH4 concentration of the NF group. Moreover，the daily CH4 production of the modified group was 295 mL，higher than the 260 mL daily methane production of the NF group，reflecting an increase of 13%. It was found that the modified NF exhibited higher hydrogen production and lower internal resistance， creating a more favorable environment for the growth and enrichment of hydrogenotrophic methanogens， thereby facilitating the electrochemical reduction of CO2 to CH4. Subsequent microbial community analysis also indicated that the relative abundance of the hydrogenotrophic methanogen Methanobacterium in the reactor with the modified NF was higher than that in the NF group，further facilitating the process of H2 serving as an electron donor for CO2 reduction to CH4. This research provides new ideas and experimental evidence for the development of novel non-precious metal composite cathode materials in bioelectrochemical systems.
2026,
44(3):
112-124.
doi: 10.13205/j.hjgc.202603010
Abstract:
Per- and polyfluoroalkyl substances （PFASs） are frequently detected at elevated concentrations in water bodies of the lower Yangtze River， posing risks to drinking water safety and human health. This study investigated the occurrence of 23 typical PFASs in source water， treated water， and tap water from eight drinking water treatment plants （DWTPs） in the lower reaches of the Yangtze River. The removal efficiency of PFASs by the treatment processes and their priority for control were also assessed. The results revealed the presence of 19 PFASs across the eight DWTPs， with total concentrations ranging from 32.02 to 167.68 ng/L and an average of 85.86 ng/L. Among these， 14 long-chain and 5 short-chain PFASs were identified， contributing 35.7% and 64.3% to the total concentration， respectively， indicating that short-chain PFASs were the predominant pollutants. The major contaminant monomers were perfluorooctanoic acid （PFOA）， perfluorobutanoic acid （PFBA）， perfluorobutanesulfonic acid （PFBS）， and perfluorohexanoic acid （PFHxA）. The overall removal efficiency of PFASs by the drinking water treatment processes was 17.8%， with a removal efficiency of 22.2% for long-chain and 15.1% for short-chain congeners. Notably， concentrations of 14 PFASs increased during distribution from the treatment plant to the tap， resulting in an overall rebound rate of 39.6%. PFBA， PFOA， and PFBS were the primary contributors， accounting for over 92.8% of this concentration increase. Modeling assessment identified PFOA， perfluorononanoic acid （PFNA）， perfluorododecanoic acid （PFDoA）， and perfluorooctanesulfonic acid （PFOS） as priority PFASs requiring enhanced monitoring and control measures.
Per- and polyfluoroalkyl substances （PFASs） are frequently detected at elevated concentrations in water bodies of the lower Yangtze River， posing risks to drinking water safety and human health. This study investigated the occurrence of 23 typical PFASs in source water， treated water， and tap water from eight drinking water treatment plants （DWTPs） in the lower reaches of the Yangtze River. The removal efficiency of PFASs by the treatment processes and their priority for control were also assessed. The results revealed the presence of 19 PFASs across the eight DWTPs， with total concentrations ranging from 32.02 to 167.68 ng/L and an average of 85.86 ng/L. Among these， 14 long-chain and 5 short-chain PFASs were identified， contributing 35.7% and 64.3% to the total concentration， respectively， indicating that short-chain PFASs were the predominant pollutants. The major contaminant monomers were perfluorooctanoic acid （PFOA）， perfluorobutanoic acid （PFBA）， perfluorobutanesulfonic acid （PFBS）， and perfluorohexanoic acid （PFHxA）. The overall removal efficiency of PFASs by the drinking water treatment processes was 17.8%， with a removal efficiency of 22.2% for long-chain and 15.1% for short-chain congeners. Notably， concentrations of 14 PFASs increased during distribution from the treatment plant to the tap， resulting in an overall rebound rate of 39.6%. PFBA， PFOA， and PFBS were the primary contributors， accounting for over 92.8% of this concentration increase. Modeling assessment identified PFOA， perfluorononanoic acid （PFNA）， perfluorododecanoic acid （PFDoA）， and perfluorooctanesulfonic acid （PFOS） as priority PFASs requiring enhanced monitoring and control measures.
2026,
44(3):
125-135.
doi: 10.13205/j.hjgc.202603011
Abstract:
This study proposed a hybrid Long Short-Term Memory （LSTM）-Transformer model integrated with wavelet denoising for water quality prediction. Using hourly monitoring data （water temperature， turbidity， pH， conductivity， and dissolved oxygen） collected from two municipally controlled river cross-sections in South China from 2021 to 2024， the discrete wavelet transform was first applied for noise reduction. Subsequently， a predictive model combining LSTM and Transformer architectures was constructed. Experimental results demonstrated that the proposed model achieved outstanding performance in predicting dissolved oxygen （DO） concentrations for the next four hours at both sites （Site 1： coefficient of determination （R2）=0.8015， mean absolute error （MAE）=0.5169 mg/L， root mean square error （RMSE）=0.8494 mg/L； Site 2： R2=0.8873， MAE=0.4456 mg/L， RMSE=0.7143 mg/L）， significantly outperforming standalone LSTM and Transformer models （the R2 of the proposed model increased by 5.7%， while MAE and RMSE decreased by 20.2% and 10.4%， respectively）.Furthermore， the SHAP interpretability method was employed for feature importance analysis and global impact interpretation， revealing that the key water quality factors influencing DO and their complex nonlinear relationships exhibited significant site-specific heterogeneity. This underscores the necessity of incorporating specific environmental contexts （e.g.， geographical features， hydrological conditions， and pollution source distribution） for mechanistic interpretation. The findings of this study provide an effective and interpretable technical reference for high-precision real-time prediction and intelligent management of regional river water quality.
This study proposed a hybrid Long Short-Term Memory （LSTM）-Transformer model integrated with wavelet denoising for water quality prediction. Using hourly monitoring data （water temperature， turbidity， pH， conductivity， and dissolved oxygen） collected from two municipally controlled river cross-sections in South China from 2021 to 2024， the discrete wavelet transform was first applied for noise reduction. Subsequently， a predictive model combining LSTM and Transformer architectures was constructed. Experimental results demonstrated that the proposed model achieved outstanding performance in predicting dissolved oxygen （DO） concentrations for the next four hours at both sites （Site 1： coefficient of determination （R2）=0.8015， mean absolute error （MAE）=0.5169 mg/L， root mean square error （RMSE）=0.8494 mg/L； Site 2： R2=0.8873， MAE=0.4456 mg/L， RMSE=0.7143 mg/L）， significantly outperforming standalone LSTM and Transformer models （the R2 of the proposed model increased by 5.7%， while MAE and RMSE decreased by 20.2% and 10.4%， respectively）.Furthermore， the SHAP interpretability method was employed for feature importance analysis and global impact interpretation， revealing that the key water quality factors influencing DO and their complex nonlinear relationships exhibited significant site-specific heterogeneity. This underscores the necessity of incorporating specific environmental contexts （e.g.， geographical features， hydrological conditions， and pollution source distribution） for mechanistic interpretation. The findings of this study provide an effective and interpretable technical reference for high-precision real-time prediction and intelligent management of regional river water quality.
2026,
44(3):
136-145.
doi: 10.13205/j.hjgc.202603012
Abstract:
As global plastic production continues to rise， the quantity of plastic waste has also increased dramatically. Effectively addressing plastic pollution while achieving the resource recovery and recycling of plastic waste has become a global challenge. Compared with conventional recycling methods， the photothermal catalysis process， which integrates photocatalysis and thermocatalysis， offers significant advantages such as high conversion efficiency and mild reaction conditions. Herein， this review outlines the research progress of photothermal catalysis technology in the treatment and resource recovery of plastic waste. It first elaborates on the mechanism of photothermal conversion， including plasmonic localized heating， non-radiative relaxation of semiconductors， and molecular thermal vibration. Based on the roles of light and heat in photothermal catalytic reactions， photothermal catalysis is classified into three categories： thermal-assisted photocatalysis， photo-driven thermocatalysis， and photo-thermal co-catalysis. The type of catalytic material plays a crucial role in regulating catalytic performance during the photothermal catalytic conversion of plastics. This review summarizes the catalytic properties of three typical photothermal catalytic materials： plasmonic metal nanoparticles， metal oxide semiconductors， and carbon-based materials， providing material design directions for efficient plastic upcycling. Furthermore， starting with the upcycling mechanisms of two representative plastics， polyethylene and polyester， the review summarizes the reaction pathways for plastic upcycling to produce liquid fuels and organic acids. Finally， based on the current research status， this review also highlights the technical challenges of using photothermal catalysis for plastic upcycling. This review aims to provide technical support for the chemical recycling of plastic waste and offer new perspectives for its upcycling.
As global plastic production continues to rise， the quantity of plastic waste has also increased dramatically. Effectively addressing plastic pollution while achieving the resource recovery and recycling of plastic waste has become a global challenge. Compared with conventional recycling methods， the photothermal catalysis process， which integrates photocatalysis and thermocatalysis， offers significant advantages such as high conversion efficiency and mild reaction conditions. Herein， this review outlines the research progress of photothermal catalysis technology in the treatment and resource recovery of plastic waste. It first elaborates on the mechanism of photothermal conversion， including plasmonic localized heating， non-radiative relaxation of semiconductors， and molecular thermal vibration. Based on the roles of light and heat in photothermal catalytic reactions， photothermal catalysis is classified into three categories： thermal-assisted photocatalysis， photo-driven thermocatalysis， and photo-thermal co-catalysis. The type of catalytic material plays a crucial role in regulating catalytic performance during the photothermal catalytic conversion of plastics. This review summarizes the catalytic properties of three typical photothermal catalytic materials： plasmonic metal nanoparticles， metal oxide semiconductors， and carbon-based materials， providing material design directions for efficient plastic upcycling. Furthermore， starting with the upcycling mechanisms of two representative plastics， polyethylene and polyester， the review summarizes the reaction pathways for plastic upcycling to produce liquid fuels and organic acids. Finally， based on the current research status， this review also highlights the technical challenges of using photothermal catalysis for plastic upcycling. This review aims to provide technical support for the chemical recycling of plastic waste and offer new perspectives for its upcycling.
2026,
44(3):
146-154.
doi: 10.13205/j.hjgc.202603013
Abstract:
Vivianite crystallization is recognized as an efficient and environmentally friendly approach for phosphorus recovery in wastewater resource utilization. However， in practical phosphorus recovery processes， the dissolved organic matter （DOM） present in the supernatant of sludge anaerobic fermentation may interfere with vivianite crystallization， thereby affecting both the phosphorus recovery efficiency and the product properties. In this study， polysaccharides， proteins， acetic acid， propionic acid， and humic substances were selected as representative organic matter to systematically assess how their types and concentrations affect vivianite crystallization， and to elucidate their impacts on crystal morphologies and structure as well as the associated interaction mechanisms. The results showed that the inhibitory effects of different types of organic matter on phosphorus recovery via vivianite crystallization followed the order of humic substances > proteins > propionic acid > acetic acid > polysaccharides. The presence of humic substances significantly reduced the phosphorus recovery rate and crystal size， and led to the formation of irregular surface deposits on the crystals. This study provides a theoretical foundation for clarifying the interference mechanism of DOM in vivianite crystallization within fermentation broth and offers insights for its regulation. These findings are of great importance for guiding the optimization of the efficient phosphorus recovery processes in real wastewater systems.
Vivianite crystallization is recognized as an efficient and environmentally friendly approach for phosphorus recovery in wastewater resource utilization. However， in practical phosphorus recovery processes， the dissolved organic matter （DOM） present in the supernatant of sludge anaerobic fermentation may interfere with vivianite crystallization， thereby affecting both the phosphorus recovery efficiency and the product properties. In this study， polysaccharides， proteins， acetic acid， propionic acid， and humic substances were selected as representative organic matter to systematically assess how their types and concentrations affect vivianite crystallization， and to elucidate their impacts on crystal morphologies and structure as well as the associated interaction mechanisms. The results showed that the inhibitory effects of different types of organic matter on phosphorus recovery via vivianite crystallization followed the order of humic substances > proteins > propionic acid > acetic acid > polysaccharides. The presence of humic substances significantly reduced the phosphorus recovery rate and crystal size， and led to the formation of irregular surface deposits on the crystals. This study provides a theoretical foundation for clarifying the interference mechanism of DOM in vivianite crystallization within fermentation broth and offers insights for its regulation. These findings are of great importance for guiding the optimization of the efficient phosphorus recovery processes in real wastewater systems.
2026,
44(3):
155-167.
doi: 10.13205/j.hjgc.202603014
Abstract:
In response to the severe global challenge of increasing microbial resistance， developing efficient and environmentally friendly antibacterial materials has become an urgent demand in the field of materials science. This research used natural dolomite from a region in Hunan as the raw material and investigated the controllable preparation process of antibacterial magnesium oxide （MgO） via the dolomite carbonation method， focusing on the regulation mechanisms of the microstructure of the product through heavy magnesium hydrolysis methods （spray pyrolysis and vacuum pyrolysis） and precursor calcination conditions. By systematically optimizing the process parameters， the optimal calcination conditions for dolomite were determined to be 1000 °C for 180 minutes， with a carbonation endpoint pH of 7.5， under which the magnesium recovery efficiency achieved the highest. Spray pyrolysis at a feed rate of 30 mL/min and 220 °C produced well-shaped hollow spherical MgCO3·3H2O precursors； when this precursor was calcined at 600 °C with a heating rate of 10 °C/min for 3 hours， high-activity MgO with a high specific surface area （49.43 m2/g）， nanoscale particle size （d50=222.47 nm）， and a hierarchical porous structure was successfully obtained. Antibacterial tests showed that this MgO material achieved a 100% sterilization efficiency against Escherichia coli， with a minimum bactericidal concentration of 0.5 mg/mL， demonstrating excellent antibacterial efficacy. By constructing a "process-structure-performance" regulation system， this study provides reliable theoretical guidance and technical support for the preparation of high-performance， environmentally friendly nanostructured antibacterial materials based on natural dolomite.
In response to the severe global challenge of increasing microbial resistance， developing efficient and environmentally friendly antibacterial materials has become an urgent demand in the field of materials science. This research used natural dolomite from a region in Hunan as the raw material and investigated the controllable preparation process of antibacterial magnesium oxide （MgO） via the dolomite carbonation method， focusing on the regulation mechanisms of the microstructure of the product through heavy magnesium hydrolysis methods （spray pyrolysis and vacuum pyrolysis） and precursor calcination conditions. By systematically optimizing the process parameters， the optimal calcination conditions for dolomite were determined to be 1000 °C for 180 minutes， with a carbonation endpoint pH of 7.5， under which the magnesium recovery efficiency achieved the highest. Spray pyrolysis at a feed rate of 30 mL/min and 220 °C produced well-shaped hollow spherical MgCO3·3H2O precursors； when this precursor was calcined at 600 °C with a heating rate of 10 °C/min for 3 hours， high-activity MgO with a high specific surface area （49.43 m2/g）， nanoscale particle size （d50=222.47 nm）， and a hierarchical porous structure was successfully obtained. Antibacterial tests showed that this MgO material achieved a 100% sterilization efficiency against Escherichia coli， with a minimum bactericidal concentration of 0.5 mg/mL， demonstrating excellent antibacterial efficacy. By constructing a "process-structure-performance" regulation system， this study provides reliable theoretical guidance and technical support for the preparation of high-performance， environmentally friendly nanostructured antibacterial materials based on natural dolomite.
2026,
44(3):
168-176.
doi: 10.13205/j.hjgc.202603015
Abstract:
The widespread use of tetracycline has resulted in elevated antibiotic concentrations in natural water bodies， posing significant threats to aquatic ecosystems and public health. Although iron-manganese modified biochar （IMBC） can effectively remove tetracycline， its powdered form is prone to leaching during application， leading to reduced utilization efficiency and potential system clogging. In this study， foam concrete （FC） was employed as an immobilization matrix to fabricate a novel iron-manganese modified biochar foam concrete （IMBC-FC） composite. The results showed that sufficient hydration reactions occurred during the immobilization process， endowing IMBC-FC with a highly porous structure that effectively avoided the masking of active sites on IMBC. The tetracycline removal efficiency of IMBC-FC reached 87.7%， and the impact of immobilization on the removal performance of IMBC was less than 10%. Removal pathway analysis indicated that oxidative degradation contributed approximately 56.9% to tetracycline removal， and singlet oxygen （1O2） was identified as the dominant reactive oxygen species （ROS） in the system. Functional groups such as hydroxyl （—OH） and carboxyl （—COO-） generated during hydration likely participated in both ROS generation and electron transfer， thus synergistically facilitating the degradation process. Furthermore， a comprehensive evaluation of the engineering application performance of IMBC-FC was carried out in accordance with relevant standards for water treatment filter media and constructed wetland substrates. The results demonstrated that IMBC-FC exhibits excellent advantages in porosity， mechanical strength， and tetracycline removal efficiency， indicating its promising engineering application prospects. This study is expected to provide a reliable technical pathway and theoretical support for the efficient immobilization of metal-modified biochar.
The widespread use of tetracycline has resulted in elevated antibiotic concentrations in natural water bodies， posing significant threats to aquatic ecosystems and public health. Although iron-manganese modified biochar （IMBC） can effectively remove tetracycline， its powdered form is prone to leaching during application， leading to reduced utilization efficiency and potential system clogging. In this study， foam concrete （FC） was employed as an immobilization matrix to fabricate a novel iron-manganese modified biochar foam concrete （IMBC-FC） composite. The results showed that sufficient hydration reactions occurred during the immobilization process， endowing IMBC-FC with a highly porous structure that effectively avoided the masking of active sites on IMBC. The tetracycline removal efficiency of IMBC-FC reached 87.7%， and the impact of immobilization on the removal performance of IMBC was less than 10%. Removal pathway analysis indicated that oxidative degradation contributed approximately 56.9% to tetracycline removal， and singlet oxygen （1O2） was identified as the dominant reactive oxygen species （ROS） in the system. Functional groups such as hydroxyl （—OH） and carboxyl （—COO-） generated during hydration likely participated in both ROS generation and electron transfer， thus synergistically facilitating the degradation process. Furthermore， a comprehensive evaluation of the engineering application performance of IMBC-FC was carried out in accordance with relevant standards for water treatment filter media and constructed wetland substrates. The results demonstrated that IMBC-FC exhibits excellent advantages in porosity， mechanical strength， and tetracycline removal efficiency， indicating its promising engineering application prospects. This study is expected to provide a reliable technical pathway and theoretical support for the efficient immobilization of metal-modified biochar.
2026,
44(3):
177-188.
doi: 10.13205/j.hjgc.202603016
Abstract:
Under the context of global warming， it is imperative to advance the synergistic efficiency of pollution reduction and carbon mitigation in the wastewater treatment industry. This study is based on the 2023 operational data from three typical municipal wastewater treatment plants （WWTPs） in Jiangsu Province employing A2/O and its modified processes. Using the emission factor method， carbon emission accounting and characteristic analysis were conducted. and explored the impact of influent characteristics and operational parameters on the carbon emissions of WWTPs through path analysis. From an indirect control perspective， this study assessed the carbon reduction potential of measures such as photovoltaic power generation and water-source heat pumps. The results indicate that： The total carbon emission intensity of the three typical WWTPs ranged from 0.578 kg/m3 to 0.671 kg/m3， with total carbon emissions between 18890 t and 28150 t. The indirect carbon emissions account for a relatively high proportion （71.7%） of the total carbon emissions in A2/O wastewater treatment plant， with electricity consumption contributing the most （53.3%） to the carbon emissions. The carbon emissions attributed to carbon source dosage accounted for the largest proportion of chemical consumption， reaching 36.9% to 59.5% of the total chemical carbon emissions. The operation of wastewater treatment plants with lower influent concentrations requires higher energy and material consumption， resulting in greater indirect carbon emissions. Furthermore， the influent water quality characteristics and operational parameters of typical A2/O process wastewater treatment plants all have direct or indirect impacts on various types of carbon emission intensities. To effectively control carbon emissions， plants can actively optimize process operational parameter adjustments， implement equipment upgrades and retrofits， adopt intelligent/smart control systems， and implement various carbon-alternative measures. By adopting PV power generation and water-source heat pumps， WWTP2 could theoretically achieve 22.7% and 100.2% carbon displacement rates， respectively， demonstrating significant carbon reduction potential.
Under the context of global warming， it is imperative to advance the synergistic efficiency of pollution reduction and carbon mitigation in the wastewater treatment industry. This study is based on the 2023 operational data from three typical municipal wastewater treatment plants （WWTPs） in Jiangsu Province employing A2/O and its modified processes. Using the emission factor method， carbon emission accounting and characteristic analysis were conducted. and explored the impact of influent characteristics and operational parameters on the carbon emissions of WWTPs through path analysis. From an indirect control perspective， this study assessed the carbon reduction potential of measures such as photovoltaic power generation and water-source heat pumps. The results indicate that： The total carbon emission intensity of the three typical WWTPs ranged from 0.578 kg/m3 to 0.671 kg/m3， with total carbon emissions between 18890 t and 28150 t. The indirect carbon emissions account for a relatively high proportion （71.7%） of the total carbon emissions in A2/O wastewater treatment plant， with electricity consumption contributing the most （53.3%） to the carbon emissions. The carbon emissions attributed to carbon source dosage accounted for the largest proportion of chemical consumption， reaching 36.9% to 59.5% of the total chemical carbon emissions. The operation of wastewater treatment plants with lower influent concentrations requires higher energy and material consumption， resulting in greater indirect carbon emissions. Furthermore， the influent water quality characteristics and operational parameters of typical A2/O process wastewater treatment plants all have direct or indirect impacts on various types of carbon emission intensities. To effectively control carbon emissions， plants can actively optimize process operational parameter adjustments， implement equipment upgrades and retrofits， adopt intelligent/smart control systems， and implement various carbon-alternative measures. By adopting PV power generation and water-source heat pumps， WWTP2 could theoretically achieve 22.7% and 100.2% carbon displacement rates， respectively， demonstrating significant carbon reduction potential.
2026,
44(3):
189-196.
doi: 10.13205/j.hjgc.202603017
Abstract:
The green and low-carbon construction of river regulation projects is an important part of the green transformation of water conservancy projects under the goals of "carbon peaking and carbon neutrality". Aiming at the common problems existing in the green and low-carbon construction of traditional river regulation projects， such as excessive qualitative descriptions of strategies， insufficient life cycle assessment （LCA）， excessive process analysis， and inadequate multi-scenario guidance， this paper took the demonstration section of the Jurong River Regulation Project in Nanjing as a case study. Based on identifying the carbon emission characteristics of river regulation projects via LCA， an environment-economic dual-objective model was adopted to conduct scenario analysis for the selection of green and low-carbon construction technologies under different objectives， and corresponding combined strategies of green and low-carbon technical measures were proposed. The results showed that the carbon emission intensity during the construction period of the Jurong River demonstration section（length 8.46 km） was 2705 t CO2eq/km， among which the raw material production stage accounted for 92.49%， followed by the engineering construction stage （5.75%）， engineering transportation （1.06%）， and engineering preparation （0.70%）. Multi-scenario analysis indicated that the application of measures including low-carbon new energy transportation， fly ash， and recycled concrete could reduce carbon emissions by 4486 t CO2eq and achieve an optimal economic benefit of RMB 1.0814 million. The combination of fly ash， recycled aggregate concrete， and carbon capture and reduction cement （with a replacement rate of 90.32%） could reduce emissions by 7551 t CO2eq， realizing a balance between economic and environmental performance. Implementing all carbon reduction measures could achieve a carbon reduction of 9596 t CO2eq but would require an investment of RMB 1.1337 million. The scenarios of maximum economic benefit and economic-ecological balance present better engineering applicability and can provide a decision-making basis for the green and low-carbon construction of river regulation projects.
The green and low-carbon construction of river regulation projects is an important part of the green transformation of water conservancy projects under the goals of "carbon peaking and carbon neutrality". Aiming at the common problems existing in the green and low-carbon construction of traditional river regulation projects， such as excessive qualitative descriptions of strategies， insufficient life cycle assessment （LCA）， excessive process analysis， and inadequate multi-scenario guidance， this paper took the demonstration section of the Jurong River Regulation Project in Nanjing as a case study. Based on identifying the carbon emission characteristics of river regulation projects via LCA， an environment-economic dual-objective model was adopted to conduct scenario analysis for the selection of green and low-carbon construction technologies under different objectives， and corresponding combined strategies of green and low-carbon technical measures were proposed. The results showed that the carbon emission intensity during the construction period of the Jurong River demonstration section（length 8.46 km） was 2705 t CO2eq/km， among which the raw material production stage accounted for 92.49%， followed by the engineering construction stage （5.75%）， engineering transportation （1.06%）， and engineering preparation （0.70%）. Multi-scenario analysis indicated that the application of measures including low-carbon new energy transportation， fly ash， and recycled concrete could reduce carbon emissions by 4486 t CO2eq and achieve an optimal economic benefit of RMB 1.0814 million. The combination of fly ash， recycled aggregate concrete， and carbon capture and reduction cement （with a replacement rate of 90.32%） could reduce emissions by 7551 t CO2eq， realizing a balance between economic and environmental performance. Implementing all carbon reduction measures could achieve a carbon reduction of 9596 t CO2eq but would require an investment of RMB 1.1337 million. The scenarios of maximum economic benefit and economic-ecological balance present better engineering applicability and can provide a decision-making basis for the green and low-carbon construction of river regulation projects.
2026,
44(3):
197-205.
doi: 10.13205/j.hjgc.202603018
Abstract:
Coastal wetland ecosystems are intrinsically linked to regional socioeconomic development. However， the internal response relationship between these two systems remains unclear. This study took Dongtai City as a study case and used systematic field sampling and multi-source data integration. Partial least squares structural equation modeling （PLS-SEM） was employed to analyze the coupled relationships among socioeconomic development， river surface water quality， and sediment carbon and nitrogen characteristics. The results indicated that over the past five years， both the socioeconomic level and urbanization rate of Dongtai City have increased steadily. Water quality exhibited significant seasonal fluctuations， while a marked declining trend in total nitrogen （TN） was observed. Meanwhile， total organic carbon （TOC） and TN contents in coastal wetland sediments showed minor fluctuations. The PLS-SEM analysis revealed that socioeconomic development indirectly regulated TOC and TN contents in coastal wetlands （path coefficient = 0.1， P < 0.05） by influencing the surface water pollution load of rivers （path coefficient = -0.33， P < 0.001）. This study elucidated the internal nexus between macro-socioeconomic drivers and micro-nutrient characteristics in coastal wetlands， providing a scientific foundation for the synergistic advancement of ecological conservation and the marine economy.
Coastal wetland ecosystems are intrinsically linked to regional socioeconomic development. However， the internal response relationship between these two systems remains unclear. This study took Dongtai City as a study case and used systematic field sampling and multi-source data integration. Partial least squares structural equation modeling （PLS-SEM） was employed to analyze the coupled relationships among socioeconomic development， river surface water quality， and sediment carbon and nitrogen characteristics. The results indicated that over the past five years， both the socioeconomic level and urbanization rate of Dongtai City have increased steadily. Water quality exhibited significant seasonal fluctuations， while a marked declining trend in total nitrogen （TN） was observed. Meanwhile， total organic carbon （TOC） and TN contents in coastal wetland sediments showed minor fluctuations. The PLS-SEM analysis revealed that socioeconomic development indirectly regulated TOC and TN contents in coastal wetlands （path coefficient = 0.1， P < 0.05） by influencing the surface water pollution load of rivers （path coefficient = -0.33， P < 0.001）. This study elucidated the internal nexus between macro-socioeconomic drivers and micro-nutrient characteristics in coastal wetlands， providing a scientific foundation for the synergistic advancement of ecological conservation and the marine economy.
