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2026 Vol. 44, No. 8
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2026, 44(8): 1-11.
doi: 10.13205/j.hjgc.202608001
Abstract:
The discharging wastewater from spent lithium-ion batteries is characterized by complex composition， high salinity， and substantial organic load， making its efficient treatment and resource recovery a critical challenge in the lithium battery recycling chain. This study investigated the feasibility of applying anaerobic chain elongation technology for resource recovery from such wastewater. The results showed that the reactor could tolerate up to 40% discharge wastewater in the feed， with caproate production reaching 6.38 g/L. However， when the wastewater proportion increased to 60%， system performance declined sharply， and the synthesis of butyrate and caproate ceased. Batch screening experiments ruled out the influence of high salinity ［ρ（TDS）≈12 g/L］ and metal ions such as Li+， Ni2+， Co2+， and Mn2+， identifying fluoride （F-） as the dominant inhibitory factor leading to functional failure. Concentration gradient experiments further quantified the inhibitory effect of F-. At concentrations below 600 mg/L， butyrate production remained largely unaffected； at 900 mg/L， substrate metabolism was severely inhibited， with only slight recovery observed at the final stage； and at 1200 mg/L， chain elongation metabolism was completely blocked. Microbial community analysis revealed that the chain elongation function was undertaken by different taxonomic groups at different stages. Initially， Clostridium kluyveri dominated， followed by a shift to Caproicibacterium and Thermocaproicibacter during the mid-phase. In the recovery phase， a synergistic consortium of Oscillibacter valericigenes and Caproicibacteriumsp. emerged. Furthermore， after introducing actual discharging wastewater， microbial groups such as Brevundimonas diminuta and Clostridiumljungdahlii， which are likely involved in degrading complex organics， gradually became enriched， providing the substrate foundation for chain elongation. This study offers a feasible strategy and mechanistic insights for the high-value bioconversion of wastewater from lithium battery recycling.
The discharging wastewater from spent lithium-ion batteries is characterized by complex composition， high salinity， and substantial organic load， making its efficient treatment and resource recovery a critical challenge in the lithium battery recycling chain. This study investigated the feasibility of applying anaerobic chain elongation technology for resource recovery from such wastewater. The results showed that the reactor could tolerate up to 40% discharge wastewater in the feed， with caproate production reaching 6.38 g/L. However， when the wastewater proportion increased to 60%， system performance declined sharply， and the synthesis of butyrate and caproate ceased. Batch screening experiments ruled out the influence of high salinity ［ρ（TDS）≈12 g/L］ and metal ions such as Li+， Ni2+， Co2+， and Mn2+， identifying fluoride （F-） as the dominant inhibitory factor leading to functional failure. Concentration gradient experiments further quantified the inhibitory effect of F-. At concentrations below 600 mg/L， butyrate production remained largely unaffected； at 900 mg/L， substrate metabolism was severely inhibited， with only slight recovery observed at the final stage； and at 1200 mg/L， chain elongation metabolism was completely blocked. Microbial community analysis revealed that the chain elongation function was undertaken by different taxonomic groups at different stages. Initially， Clostridium kluyveri dominated， followed by a shift to Caproicibacterium and Thermocaproicibacter during the mid-phase. In the recovery phase， a synergistic consortium of Oscillibacter valericigenes and Caproicibacteriumsp. emerged. Furthermore， after introducing actual discharging wastewater， microbial groups such as Brevundimonas diminuta and Clostridiumljungdahlii， which are likely involved in degrading complex organics， gradually became enriched， providing the substrate foundation for chain elongation. This study offers a feasible strategy and mechanistic insights for the high-value bioconversion of wastewater from lithium battery recycling.
2026, 44(8): 12-18.
doi: 10.13205/j.hjgc.202608002
Abstract:
Under the synergistic policy framework of carbon peaking， carbon neutrality and the circular economy， existing carbon capture， utilization and storage （CCUS） projects in coal-fired power plants （CFPPs） continue to face significant challenges， including high regeneration energy demand， reliance on turbine steam extraction， limited carbon utilization pathways， poor economic viability and difficulties in by-product management. To address these limitations， this study proposed an integrated low-carbon retrofitting strategy that couples molten-salt thermal energy storage （TES） and microalgal carbon fixation systems with existing CCUS facilities under minimal plant modification. A closed-loop carbon and energy utilization framework was established， integrating waste heat recovery， primary CO2 capture， secondary biological carbon fixation and biomass fuel recycling. The proposed system operates through a gradient synergistic mechanism： （i） recovered waste heat is stored in a molten-salt TES unit to provide regeneration energy， thereby replacing conventional steam extraction； （ii） CO2 is initially captured by the CCUS process； （iii） residual CO2 is further utilized by microalgae for deep carbon fixation； and （iv） the harvested algal sludge is converted into biomass fuel for co-firing within the power plant， completing the carbon recycling loop. The technical architecture， coupling mechanisms， scenario-specific implementation pathways and operational risk control strategies were systematically evaluated. The results indicate that the integrated system can reduce energy consumption by approximately 30% to 40% per unit of CO2 captured， increase the overall carbon fixation efficiency by 15% to 20%， and shorten the investment payback period to less than five years. Furthermore， the proposed framework enables the transformation of conventional coal-fired power plants from single-purpose energy producers into multifunctional circular systems integrating energy generation， carbon cycling and resource recovery. Owing to the technological maturity of its constituent components， strong adaptability to different plant capacities and geographical conditions， and a clear deployment roadmap from pilot demonstration to large-scale implementation， this integrated solution provides a practical， replicable and scalable pathway for the low-carbon and circular transition of China's thermal power sector.
Under the synergistic policy framework of carbon peaking， carbon neutrality and the circular economy， existing carbon capture， utilization and storage （CCUS） projects in coal-fired power plants （CFPPs） continue to face significant challenges， including high regeneration energy demand， reliance on turbine steam extraction， limited carbon utilization pathways， poor economic viability and difficulties in by-product management. To address these limitations， this study proposed an integrated low-carbon retrofitting strategy that couples molten-salt thermal energy storage （TES） and microalgal carbon fixation systems with existing CCUS facilities under minimal plant modification. A closed-loop carbon and energy utilization framework was established， integrating waste heat recovery， primary CO2 capture， secondary biological carbon fixation and biomass fuel recycling. The proposed system operates through a gradient synergistic mechanism： （i） recovered waste heat is stored in a molten-salt TES unit to provide regeneration energy， thereby replacing conventional steam extraction； （ii） CO2 is initially captured by the CCUS process； （iii） residual CO2 is further utilized by microalgae for deep carbon fixation； and （iv） the harvested algal sludge is converted into biomass fuel for co-firing within the power plant， completing the carbon recycling loop. The technical architecture， coupling mechanisms， scenario-specific implementation pathways and operational risk control strategies were systematically evaluated. The results indicate that the integrated system can reduce energy consumption by approximately 30% to 40% per unit of CO2 captured， increase the overall carbon fixation efficiency by 15% to 20%， and shorten the investment payback period to less than five years. Furthermore， the proposed framework enables the transformation of conventional coal-fired power plants from single-purpose energy producers into multifunctional circular systems integrating energy generation， carbon cycling and resource recovery. Owing to the technological maturity of its constituent components， strong adaptability to different plant capacities and geographical conditions， and a clear deployment roadmap from pilot demonstration to large-scale implementation， this integrated solution provides a practical， replicable and scalable pathway for the low-carbon and circular transition of China's thermal power sector.
2026, 44(8): 19-31.
doi: 10.13205/j.hjgc.202608003
Abstract:
Driven by the Dual Carbon Goals and the imperative concept of a circular economy， transitioning municipal wastewater treatment from traditional energy-intensive aerobic processes to sustainable， energy-recovering anaerobic technologies has become highly essential for the water industry. However， the practical application of anaerobic biological treatment for low-strength municipal wastewater often faces severe operational challenges， particularly those recovering from unexpected equipment shutdowns， long-term starvation， and seasonal low-temperature fluctuations. To systematically address these critical issues in pilot-scale applications， a pilot-scale anaerobic filter （AF） packed with volcanic rock media was employed to treat actual municipal wastewater； the reactor， with an effective volume of 240 L， was evaluated over multiple continuous operational phases. This study comprehensively investigated the system’s performance recovery following an extended 234-day period of starvation， and the subsequent impact of continuous low-temperature stress on operational efficiency， pollutant spatial distribution， and microbial community structure. The experimental results demonstrated that extending the hydraulic retention time from 8 to 12 hours facilitated the rapid recovery of the AF； upon achieving stable recovery， the removal amounts of total chemical oxygen demand （TCOD） and soluble chemical oxygen demand （SCOD） reached 58.6 mg/L and 21.5 mg/L， respectively， and following a continuous 100-day period of low-temperature operation（ the influent temperature dropped to as low as 11.7 ℃）， the TCOD and SCOD removal amounts remained 54.6 mg/L and 28.6 mg/L， respectively. Although the extremely low temperature decreased the overall CH4 production volume， the specific CH4 yield was not significantly affected， thereby maintaining an efficient energy conversion rate； mechanistic investigations revealed that， under low-temperature conditions， the secretion of proteins within extracellular polymeric substances （EPS） significantly increased and exhibited a strong negative correlation with the temperature gradient along the filter height. The massive protein secretion played a crucial protective role in resisting low-temperature stress， thereby enabling the system to maintain structural integrity and operate stably. High-throughput sequencing and quantitative polymerase chain reaction analysis of the microbial community revealed a distinct spatial and temporal succession； after the long-term starvation period， the functional microbiomes recovered sequentially in the strict order of hydrolytic-acidogenic bacteria， hydrogen-producing acetogenic bacteria， and methanogens， and during this initial recovery phase， the CO2-reducing methanogen Methanobacterium dominated the methanogenic community； however， following the prolonged low-temperature period， a significant pathway shift occurred， and the acetoclastic methanogen Methanosaeta， relying on its high affinity for acetate， became the dominant methanogen in the system. Furthermore， low-temperature stress promoted a unique spatial functional stratification， leading to a substantial enrichment of hydrolytic-acidogenic and hydrogen-producing acetogenic bacteria in the upper-middle layers of the filter， which significantly improved the effective utilization of the reactor volume. Finally， a comprehensive energy and carbon footprint accounting indicated that， except for the extreme scenario where the influent temperature dropped to 11.7 ℃， the recovered CH4 electrical energy could fully satisfy the baseline energy consumption of the system’s peristaltic pump； furthermore， coupling the anaerobic filter effluent with a nitrate-dependent anaerobic methane oxidation process proved to be the optimal technological pathway for preventing dissolved methane emission and achieving deep carbon emission reduction. These findings provide vital theoretical support， precise spatial-temporal microbial mechanisms， and a highly practical engineering paradigm for the resilient operation and carbon-energy synergistic optimization of full-scale anaerobic wastewater treatment facilities under extreme environmental conditions.
Driven by the Dual Carbon Goals and the imperative concept of a circular economy， transitioning municipal wastewater treatment from traditional energy-intensive aerobic processes to sustainable， energy-recovering anaerobic technologies has become highly essential for the water industry. However， the practical application of anaerobic biological treatment for low-strength municipal wastewater often faces severe operational challenges， particularly those recovering from unexpected equipment shutdowns， long-term starvation， and seasonal low-temperature fluctuations. To systematically address these critical issues in pilot-scale applications， a pilot-scale anaerobic filter （AF） packed with volcanic rock media was employed to treat actual municipal wastewater； the reactor， with an effective volume of 240 L， was evaluated over multiple continuous operational phases. This study comprehensively investigated the system’s performance recovery following an extended 234-day period of starvation， and the subsequent impact of continuous low-temperature stress on operational efficiency， pollutant spatial distribution， and microbial community structure. The experimental results demonstrated that extending the hydraulic retention time from 8 to 12 hours facilitated the rapid recovery of the AF； upon achieving stable recovery， the removal amounts of total chemical oxygen demand （TCOD） and soluble chemical oxygen demand （SCOD） reached 58.6 mg/L and 21.5 mg/L， respectively， and following a continuous 100-day period of low-temperature operation（ the influent temperature dropped to as low as 11.7 ℃）， the TCOD and SCOD removal amounts remained 54.6 mg/L and 28.6 mg/L， respectively. Although the extremely low temperature decreased the overall CH4 production volume， the specific CH4 yield was not significantly affected， thereby maintaining an efficient energy conversion rate； mechanistic investigations revealed that， under low-temperature conditions， the secretion of proteins within extracellular polymeric substances （EPS） significantly increased and exhibited a strong negative correlation with the temperature gradient along the filter height. The massive protein secretion played a crucial protective role in resisting low-temperature stress， thereby enabling the system to maintain structural integrity and operate stably. High-throughput sequencing and quantitative polymerase chain reaction analysis of the microbial community revealed a distinct spatial and temporal succession； after the long-term starvation period， the functional microbiomes recovered sequentially in the strict order of hydrolytic-acidogenic bacteria， hydrogen-producing acetogenic bacteria， and methanogens， and during this initial recovery phase， the CO2-reducing methanogen Methanobacterium dominated the methanogenic community； however， following the prolonged low-temperature period， a significant pathway shift occurred， and the acetoclastic methanogen Methanosaeta， relying on its high affinity for acetate， became the dominant methanogen in the system. Furthermore， low-temperature stress promoted a unique spatial functional stratification， leading to a substantial enrichment of hydrolytic-acidogenic and hydrogen-producing acetogenic bacteria in the upper-middle layers of the filter， which significantly improved the effective utilization of the reactor volume. Finally， a comprehensive energy and carbon footprint accounting indicated that， except for the extreme scenario where the influent temperature dropped to 11.7 ℃， the recovered CH4 electrical energy could fully satisfy the baseline energy consumption of the system’s peristaltic pump； furthermore， coupling the anaerobic filter effluent with a nitrate-dependent anaerobic methane oxidation process proved to be the optimal technological pathway for preventing dissolved methane emission and achieving deep carbon emission reduction. These findings provide vital theoretical support， precise spatial-temporal microbial mechanisms， and a highly practical engineering paradigm for the resilient operation and carbon-energy synergistic optimization of full-scale anaerobic wastewater treatment facilities under extreme environmental conditions.
2026, 44(8): 32-41.
doi: 10.13205/j.hjgc.202608004
Abstract:
This paper innovatively presents the design and implementation of an on-site thermal treatment system for medical organic waste liquid at the source. The system achieves a tight integration of automatic control with energy-efficient and eco- friendly operation at the equipment level. It enables immediate treatment of waste liquid at the source， leading to a reduction in storage and transportation volumes by over 95%. Consequently， it eliminates potential safety hazards and environmental risks associated with traditional waste liquid management and treatment processes. The system design primarily consists of four modules： a waste liquid identification module， a graded thermal treatment module， a heat recovery module， and a tail gas purification module. Among these， the specially developed graded thermal treatment technology can effectively process hazardous medical organic waste liquids with different compositions and calorific values. Finally， on-site treatment experiments were conducted on four typical types of hazardous medical organic waste liquids to validate the feasibility of the system. The results demonstrate that the system can achieve effective treatment of hazardous medical organic waste liquid， meeting the safety and environmental protection requirements while offering certain economic benefits.
This paper innovatively presents the design and implementation of an on-site thermal treatment system for medical organic waste liquid at the source. The system achieves a tight integration of automatic control with energy-efficient and eco- friendly operation at the equipment level. It enables immediate treatment of waste liquid at the source， leading to a reduction in storage and transportation volumes by over 95%. Consequently， it eliminates potential safety hazards and environmental risks associated with traditional waste liquid management and treatment processes. The system design primarily consists of four modules： a waste liquid identification module， a graded thermal treatment module， a heat recovery module， and a tail gas purification module. Among these， the specially developed graded thermal treatment technology can effectively process hazardous medical organic waste liquids with different compositions and calorific values. Finally， on-site treatment experiments were conducted on four typical types of hazardous medical organic waste liquids to validate the feasibility of the system. The results demonstrate that the system can achieve effective treatment of hazardous medical organic waste liquid， meeting the safety and environmental protection requirements while offering certain economic benefits.
2026, 44(8): 42-50.
doi: 10.13205/j.hjgc.202608005
Abstract:
The increasing volume of end-of-life carbon fiber reinforced polymer （CFRP） and the high energy consumption and emissions associated with virgin fiber production underscore an urgent need for low-carbon recycling technologies. As an emerging and rapidly developing method， superheated steam pyrolysis for carbon fiber recovery is systematically reviewed in this paper. The synergistic “hydrothermal-weak oxidation” mechanism of superheated steam at 450 to 500 ℃ enables controlled resin cracking and simultaneous char removal. The effects of key parameters， including temperature， oxygen concentration， residence time， and the coupling of CO2/steam two-step processes， on the mechanical， surface， and electrical properties of recycled carbon fiber（rCF） are summarized. A “low-temperature， short-duration， micro-oxygen” process is proposed to retain over 90% of the tensile strength of rCF. A comparison of laboratory-， pilot-， and industrial-scale setups highlights the need to address exhaust gas treatment， adaptability to multi-component waste， and energy integration during process scale-up. Life cycle assessment （LCA） confirms that this recycling route can reduce energy consumption by approximately 25% and carbon emissions by about 30%， compared to landfilling/incineration， demonstrating environmental and economic advantages. Future research should focus on establishing product databases， optimizing distributed recycling networks， and developing unified LCA frameworks to provide standardized technical support and decision-making tools for CFRP closed-loop recycling.
The increasing volume of end-of-life carbon fiber reinforced polymer （CFRP） and the high energy consumption and emissions associated with virgin fiber production underscore an urgent need for low-carbon recycling technologies. As an emerging and rapidly developing method， superheated steam pyrolysis for carbon fiber recovery is systematically reviewed in this paper. The synergistic “hydrothermal-weak oxidation” mechanism of superheated steam at 450 to 500 ℃ enables controlled resin cracking and simultaneous char removal. The effects of key parameters， including temperature， oxygen concentration， residence time， and the coupling of CO2/steam two-step processes， on the mechanical， surface， and electrical properties of recycled carbon fiber（rCF） are summarized. A “low-temperature， short-duration， micro-oxygen” process is proposed to retain over 90% of the tensile strength of rCF. A comparison of laboratory-， pilot-， and industrial-scale setups highlights the need to address exhaust gas treatment， adaptability to multi-component waste， and energy integration during process scale-up. Life cycle assessment （LCA） confirms that this recycling route can reduce energy consumption by approximately 25% and carbon emissions by about 30%， compared to landfilling/incineration， demonstrating environmental and economic advantages. Future research should focus on establishing product databases， optimizing distributed recycling networks， and developing unified LCA frameworks to provide standardized technical support and decision-making tools for CFRP closed-loop recycling.
2026, 44(8): 51-62.
doi: 10.13205/j.hjgc.202608006
Abstract:
Organic waste contains abundant phosphorus （P） and is regarded as a potential P reservoir. The variation in available phosphorus （AP） during its resource utilization is of great importance for phosphorus recovery and utilization. Composting is an important approach for the resource utilization of organic waste， during which P speciation is transformed along with the degradation and humification of organic matter. However， because composting experiments are time-consuming and costly， and the process is influenced by multiple factors， the dynamic behavior of AP is difficult to reveal efficiently using conventional experiments. In this study， a dataset containing 647 samples was compiled from the literature. Data preprocessing was implemented via iterative imputation， one-hot encoding， and standardization. A predictive model for AP formation during composting was developed using a stacking ensemble learning method. Shapley additive explanations （SHAP） and partial dependence plots （PDPs） were further used to identify the key factors affecting AP formation. The results showed that the best ensemble model for predicting AP during organic waste composting consisted of XGBoost and SVR as base learners and ElasticNet as the meta-learner. The model achieved R2 values of 0.954 and 0.928 for the training and test sets， respectively， indicating stable predictive performance and low overall error. Global SHAP importance analysis showed that the main factors affecting AP content were feedstock type， bulking agent type， turning interval， pH， electrical conductivity （EC）， and the C/N ratio. In particular， livestock manure as the feedstock and straw-based materials as the bulking agent made significant positive contributions to the predicted AP values. PDP analysis further showed that relatively low pH and C/N ratio generally favored AP accumulation throughout the composting period. During the initial stage of composting， higher moisture content and lower EC were more favorable for AP increase. During the early thermophilic stage， higher pile temperature was associated with higher predicted AP levels. During the cooling and maturation stage， AP accumulation was further promoted when moisture content （< 48%） and C/N ratio （< 14） were kept at relatively low levels and the composting duration was appropriately extended （> 43 d）. In this study， accurate prediction of AP content during organic waste composting was achieved using a stacking ensemble learning method， and the key factors affecting AP formation were identified through SHAP and PDP analyses. The developed model provides support for regulating AP formation and optimizing engineering applications in the composting process.
Organic waste contains abundant phosphorus （P） and is regarded as a potential P reservoir. The variation in available phosphorus （AP） during its resource utilization is of great importance for phosphorus recovery and utilization. Composting is an important approach for the resource utilization of organic waste， during which P speciation is transformed along with the degradation and humification of organic matter. However， because composting experiments are time-consuming and costly， and the process is influenced by multiple factors， the dynamic behavior of AP is difficult to reveal efficiently using conventional experiments. In this study， a dataset containing 647 samples was compiled from the literature. Data preprocessing was implemented via iterative imputation， one-hot encoding， and standardization. A predictive model for AP formation during composting was developed using a stacking ensemble learning method. Shapley additive explanations （SHAP） and partial dependence plots （PDPs） were further used to identify the key factors affecting AP formation. The results showed that the best ensemble model for predicting AP during organic waste composting consisted of XGBoost and SVR as base learners and ElasticNet as the meta-learner. The model achieved R2 values of 0.954 and 0.928 for the training and test sets， respectively， indicating stable predictive performance and low overall error. Global SHAP importance analysis showed that the main factors affecting AP content were feedstock type， bulking agent type， turning interval， pH， electrical conductivity （EC）， and the C/N ratio. In particular， livestock manure as the feedstock and straw-based materials as the bulking agent made significant positive contributions to the predicted AP values. PDP analysis further showed that relatively low pH and C/N ratio generally favored AP accumulation throughout the composting period. During the initial stage of composting， higher moisture content and lower EC were more favorable for AP increase. During the early thermophilic stage， higher pile temperature was associated with higher predicted AP levels. During the cooling and maturation stage， AP accumulation was further promoted when moisture content （< 48%） and C/N ratio （< 14） were kept at relatively low levels and the composting duration was appropriately extended （> 43 d）. In this study， accurate prediction of AP content during organic waste composting was achieved using a stacking ensemble learning method， and the key factors affecting AP formation were identified through SHAP and PDP analyses. The developed model provides support for regulating AP formation and optimizing engineering applications in the composting process.
2026, 44(8): 63-76.
doi: 10.13205/j.hjgc.202608007
Abstract:
The Minjiang River Basin， subjected to combined pollution from domestic， agricultural， and industrial sources， has become a typical sensitive area for studying the environmental behavior of emerging contaminants such as antibiotics. This study conducted a cross-year comparative analysis of the composition and concentrations of antibiotics in water samples from nine sampling sites during the dry season in November 2022 and 2024. The findings revealed： 1） After the implementation of the “National Action Plan for Reducing Antimicrobial Use in Livestock”， the detection concentrations of tetracycline antibiotics （TCs） decreased （e.g.， doxycycline concentrations dropped from 7.75 ng/L to the undetectable level）， and the mixed risk quotient （MRQ） across the entire basin transitioned from medium to low level. However， lincomycin （up to 4.6 ng/L）， clarithromycin （1.3 ng/L）， and florfenicol （0.6 ng/L） have emerged， indicating an increasing hidden ecological risk from substitution； 2） High-concentration antibiotic zones transferred from urban residential areas in 2022 to intensive aquaculture zones and upstream reservoir areas in 2024. The reduction in dry-season water flow intensified pollutant accumulation， synergistically enhancing the effects of tidal drag. Additionally， the conversion of agricultural land to aquaculture ponds led to increased use of alternative drugs （e.g.， sulfamethazine）， while policy interventions mitigated the exacerbation of urban antibiotic pollution by construction land. This study elucidates the migration patterns of antibiotic pollution under the combined effects of policy regulation and natural processes， emphasizing focusing on the hidden risks from alternative drugs and the driving role of land-use changes. It provides a scientific basis for the risk assessment and targeted management of emerging contaminants in river basins.
The Minjiang River Basin， subjected to combined pollution from domestic， agricultural， and industrial sources， has become a typical sensitive area for studying the environmental behavior of emerging contaminants such as antibiotics. This study conducted a cross-year comparative analysis of the composition and concentrations of antibiotics in water samples from nine sampling sites during the dry season in November 2022 and 2024. The findings revealed： 1） After the implementation of the “National Action Plan for Reducing Antimicrobial Use in Livestock”， the detection concentrations of tetracycline antibiotics （TCs） decreased （e.g.， doxycycline concentrations dropped from 7.75 ng/L to the undetectable level）， and the mixed risk quotient （MRQ） across the entire basin transitioned from medium to low level. However， lincomycin （up to 4.6 ng/L）， clarithromycin （1.3 ng/L）， and florfenicol （0.6 ng/L） have emerged， indicating an increasing hidden ecological risk from substitution； 2） High-concentration antibiotic zones transferred from urban residential areas in 2022 to intensive aquaculture zones and upstream reservoir areas in 2024. The reduction in dry-season water flow intensified pollutant accumulation， synergistically enhancing the effects of tidal drag. Additionally， the conversion of agricultural land to aquaculture ponds led to increased use of alternative drugs （e.g.， sulfamethazine）， while policy interventions mitigated the exacerbation of urban antibiotic pollution by construction land. This study elucidates the migration patterns of antibiotic pollution under the combined effects of policy regulation and natural processes， emphasizing focusing on the hidden risks from alternative drugs and the driving role of land-use changes. It provides a scientific basis for the risk assessment and targeted management of emerging contaminants in river basins.
2026, 44(8): 77-94.
doi: 10.13205/j.hjgc.202608008
Abstract:
Medium-chain fatty acids （MCFAs） are promising biobased products due to their high energy density， hydrophobicity， and significant value for chemical conversion. They represent an important link between organic waste valorization and the development of a circular economy. Compared with conventional anaerobic digestion for methane production， chain elongation （CE） can further convert short-chain intermediates， such as acetate， lactate， and ethanol， into higher-value carboxylic acids， including caproate and caprylate， through the reverse β-oxidation （RBO） pathway. This process provides a novel approach for resource recovery from sewage sludge， food waste， agricultural residues， livestock manure， and high-strength organic wastewater. However， CE systems driven by natural mixed microbial communities are still constrained by fluctuations in substrate composition， competition for electron donors， carbon diversion to methanogenesis， insufficient product selectivity， product toxicity， and high separation costs， all of which limit the stable， efficient， and targeted production of MCFAs. Focusing on the interdisciplinary demands of environmental sustainability and circular economy development， this review systematically summarizes the metabolic mechanisms， artificial regulation strategies， and engineering challenges in MCFA production via CE， with particular emphasis on the directed recovery of carbon and electron resources from organic wastes. Future perspectives are proposed regarding stable continuous-flow operation， product separation and recovery， techno-economic assessment， and life cycle evaluation. This review aims to provide insights into the high-value utilization of organic wastes and the synergistic optimization of carbon and energy resource recovery.
Medium-chain fatty acids （MCFAs） are promising biobased products due to their high energy density， hydrophobicity， and significant value for chemical conversion. They represent an important link between organic waste valorization and the development of a circular economy. Compared with conventional anaerobic digestion for methane production， chain elongation （CE） can further convert short-chain intermediates， such as acetate， lactate， and ethanol， into higher-value carboxylic acids， including caproate and caprylate， through the reverse β-oxidation （RBO） pathway. This process provides a novel approach for resource recovery from sewage sludge， food waste， agricultural residues， livestock manure， and high-strength organic wastewater. However， CE systems driven by natural mixed microbial communities are still constrained by fluctuations in substrate composition， competition for electron donors， carbon diversion to methanogenesis， insufficient product selectivity， product toxicity， and high separation costs， all of which limit the stable， efficient， and targeted production of MCFAs. Focusing on the interdisciplinary demands of environmental sustainability and circular economy development， this review systematically summarizes the metabolic mechanisms， artificial regulation strategies， and engineering challenges in MCFA production via CE， with particular emphasis on the directed recovery of carbon and electron resources from organic wastes. Future perspectives are proposed regarding stable continuous-flow operation， product separation and recovery， techno-economic assessment， and life cycle evaluation. This review aims to provide insights into the high-value utilization of organic wastes and the synergistic optimization of carbon and energy resource recovery.
2026, 44(8): 95-109.
doi: 10.13205/j.hjgc.202608009
Abstract:
To investigate the flow and heat transfer characteristics of natural draft direct air-cooling towers （NDC） for large coal-fired power generating units， a three-dimensional CFD numerical model covering major plant buildings， air-cooled radiators， and ambient wind fields uas established based on the NDC systems of a 2×660 MW unit of a power plant. The influences of meteorological factors， including ambient wind speed， ambient temperature and ambient wind direction， as well as regulation measures such as rolling shutters， louvers and bypass windows on the heat dissipation performance of NDC towers were systematically analyzed. The results demonstrate that ambient wind speed acts as the dominant factor governing the performance of the NDC system. As wind speed rose， the uneven distribution of air intake volume and heat dissipation among each cooling delta increased remarkably， which elevated the unit back pressure， and the upstream tower suffered more severe impacts than the downstream one. Ambient temperature exerted a slight effect on circumferential flow distribution， yet substantially changed the overall back pressure of the system. In terms of regulation strategies， closing rolling shutters in the windward zone and reducing the opening of partial louvers can improve air flow redistribution to a certain extent， but will reduce the total air flow rate and total heat dissipation of the entire tower. By contrast， bottom bypass windows can effectively optimize the air intake on the leeward side and boost heat dissipation under high-wind operating conditions， whereas top bypass windows deliver only limited improvement effects. This research can provide fundamental data and technical references for the optimal design， operational regulation， and energy-saving retrofitting of large NDC units.
To investigate the flow and heat transfer characteristics of natural draft direct air-cooling towers （NDC） for large coal-fired power generating units， a three-dimensional CFD numerical model covering major plant buildings， air-cooled radiators， and ambient wind fields uas established based on the NDC systems of a 2×660 MW unit of a power plant. The influences of meteorological factors， including ambient wind speed， ambient temperature and ambient wind direction， as well as regulation measures such as rolling shutters， louvers and bypass windows on the heat dissipation performance of NDC towers were systematically analyzed. The results demonstrate that ambient wind speed acts as the dominant factor governing the performance of the NDC system. As wind speed rose， the uneven distribution of air intake volume and heat dissipation among each cooling delta increased remarkably， which elevated the unit back pressure， and the upstream tower suffered more severe impacts than the downstream one. Ambient temperature exerted a slight effect on circumferential flow distribution， yet substantially changed the overall back pressure of the system. In terms of regulation strategies， closing rolling shutters in the windward zone and reducing the opening of partial louvers can improve air flow redistribution to a certain extent， but will reduce the total air flow rate and total heat dissipation of the entire tower. By contrast， bottom bypass windows can effectively optimize the air intake on the leeward side and boost heat dissipation under high-wind operating conditions， whereas top bypass windows deliver only limited improvement effects. This research can provide fundamental data and technical references for the optimal design， operational regulation， and energy-saving retrofitting of large NDC units.
2026, 44(8): 110-118.
doi: 10.13205/j.hjgc.202608010
Abstract:
Driven by the synergistic advancement of the Dual Carbon Strategy and the circular economy， the high-value resource utilization of coal fly ash from coal-fired power plants and the multiscale remediation of environmental pollutants have emerged as critical research topics. However， the direct construction of hierarchical porous zeolite A，which integrates a microporous framework with mesoporous mass-transfer channels，from coal fly ash remains a significant challenge. This is largely due to the complex impurity background of the raw material and the difficulty in synergistically controlling crystalline phase growth and pore architecture. To address the inherent bottlenecks of conventional microporous zeolite A， such as narrow pore channels， severe mass-transfer limitations， and inefficiencies in removing larger pollutant molecules， this study successfully synthesized a hierarchical porous zeolite A featuring a three-dimensionally interconnected mesoporous network. This was achieved via a soft-template-assisted alkali fusion-hydrothermal method， utilizing acid-treated coal fly ash as the silica-alumina source. The underlying mechanisms governing the effects of template type and dosage on the crystalline phase， morphological evolution， and pore structure of the products were systematically investigated. The results demonstrated that using 3 % dimethyloctadecyl［3-（trimethoxysilyl）propyl］ ammonium chloride （TPOAC） as the template，the prepared zeolite yielded a step-like， rough cubic morphology formed by the self-assembly of nanocrystals. Its specific surface area and total pore volume reached 57.0 m2/g and 0.1351 cm3/g， respectively， representing approximately three- and four-fold increases compared to conventional microporous zeolite A. Furthermore， aqueous ammonia nitrogen， and gaseous acetone were employed as probe pollutants to elucidate the differential response mechanisms of the hierarchical pore structure toward contaminants with distinct adsorption mechanisms. For ammonia nitrogen， which primarily relies on an ion-exchange mechanism， the hierarchical pores mainly served to improve mass transfer， yielding an adsorption capacity comparable to that of microporous zeolite A. In contrast， for larger acetone molecules restricted by the molecular sieving effect， the hierarchical porous zeolite A leveraged its highly developed mesoporous volume to effectively overcome steric diffusion hindrance. This induced highly efficient capillary condensation， resulting in a dramatic surge in acetone adsorption capacity from 12 mg/g （for conventional microporous zeolite） to 59 mg/g， a nearly four-fold increase. This study elucidates the structure-activity relationship between pore architecture evolution and differential adsorption behaviors， providing robust theoretical and technical support for the large-scale utilization of coal fly ash and the targeted design of advanced remediation materials for complex environmental pollutants.
Driven by the synergistic advancement of the Dual Carbon Strategy and the circular economy， the high-value resource utilization of coal fly ash from coal-fired power plants and the multiscale remediation of environmental pollutants have emerged as critical research topics. However， the direct construction of hierarchical porous zeolite A，which integrates a microporous framework with mesoporous mass-transfer channels，from coal fly ash remains a significant challenge. This is largely due to the complex impurity background of the raw material and the difficulty in synergistically controlling crystalline phase growth and pore architecture. To address the inherent bottlenecks of conventional microporous zeolite A， such as narrow pore channels， severe mass-transfer limitations， and inefficiencies in removing larger pollutant molecules， this study successfully synthesized a hierarchical porous zeolite A featuring a three-dimensionally interconnected mesoporous network. This was achieved via a soft-template-assisted alkali fusion-hydrothermal method， utilizing acid-treated coal fly ash as the silica-alumina source. The underlying mechanisms governing the effects of template type and dosage on the crystalline phase， morphological evolution， and pore structure of the products were systematically investigated. The results demonstrated that using 3 % dimethyloctadecyl［3-（trimethoxysilyl）propyl］ ammonium chloride （TPOAC） as the template，the prepared zeolite yielded a step-like， rough cubic morphology formed by the self-assembly of nanocrystals. Its specific surface area and total pore volume reached 57.0 m2/g and 0.1351 cm3/g， respectively， representing approximately three- and four-fold increases compared to conventional microporous zeolite A. Furthermore， aqueous ammonia nitrogen， and gaseous acetone were employed as probe pollutants to elucidate the differential response mechanisms of the hierarchical pore structure toward contaminants with distinct adsorption mechanisms. For ammonia nitrogen， which primarily relies on an ion-exchange mechanism， the hierarchical pores mainly served to improve mass transfer， yielding an adsorption capacity comparable to that of microporous zeolite A. In contrast， for larger acetone molecules restricted by the molecular sieving effect， the hierarchical porous zeolite A leveraged its highly developed mesoporous volume to effectively overcome steric diffusion hindrance. This induced highly efficient capillary condensation， resulting in a dramatic surge in acetone adsorption capacity from 12 mg/g （for conventional microporous zeolite） to 59 mg/g， a nearly four-fold increase. This study elucidates the structure-activity relationship between pore architecture evolution and differential adsorption behaviors， providing robust theoretical and technical support for the large-scale utilization of coal fly ash and the targeted design of advanced remediation materials for complex environmental pollutants.
2026, 44(8): 119-127.
doi: 10.13205/j.hjgc.202608011
Abstract:
Tetracycline is a poorly biodegradable organic pollutant that poses a serious threat to the aquatic environment. The Fenton-like method has received much attention for its high efficiency in treating tetracycline-containing wastewater. It degrades tetracycline by generating hydroxyl radicals （·OH） through the activation of H2O2， thereby improving the biodegradability of wastewater. This review presents a comprehensive summary of recent advances in the application of Fenton-like methods and heterogeneous Fenton systems， detailing their reaction mechanisms， treatment efficiencies， and technical features. Under the optimized conditions， the removal rate of tetracycline by various methods can exceed 90%. Crucially， the heterogeneous Fenton method demonstrates superior applicability over a wider pH range， reduced iron sludge production， and excellent catalyst recyclability， representing the most promising strategy for practical implementation. Finally， this review outlines future perspectives， emphasizing the need for developing novel catalysts， optimizing reactor design， controlling toxic by-products， and integrating hybrid technologies to facilitate their practical application.
Tetracycline is a poorly biodegradable organic pollutant that poses a serious threat to the aquatic environment. The Fenton-like method has received much attention for its high efficiency in treating tetracycline-containing wastewater. It degrades tetracycline by generating hydroxyl radicals （·OH） through the activation of H2O2， thereby improving the biodegradability of wastewater. This review presents a comprehensive summary of recent advances in the application of Fenton-like methods and heterogeneous Fenton systems， detailing their reaction mechanisms， treatment efficiencies， and technical features. Under the optimized conditions， the removal rate of tetracycline by various methods can exceed 90%. Crucially， the heterogeneous Fenton method demonstrates superior applicability over a wider pH range， reduced iron sludge production， and excellent catalyst recyclability， representing the most promising strategy for practical implementation. Finally， this review outlines future perspectives， emphasizing the need for developing novel catalysts， optimizing reactor design， controlling toxic by-products， and integrating hybrid technologies to facilitate their practical application.
2026, 44(8): 128-140.
doi: 10.13205/j.hjgc.202608012
Abstract:
The challenge of limited phosphorus removal efficiency in low-carbon municipal wastewater is addressed by the innovative side-stream enhanced biological phosphorus removal （S2EBPR） process，which has garnered significant attention. Recent research highlights the core mechanism rooted in the metabolic traits of phosphorus accumulating organisms （PAOs）， pivotal for effective phosphorus removal. However， conventional enhanced biological phosphorus removal （EBPR） processes face constraints under low C/P conditions， where the scarcity of carbon source weakens PAOs’ competitive edge， directly impeding phosphorus removal efficiency. Consequently， S2EBPR establishes a side-stream sludge fermentation unit， through which anaerobic fermentation conditions are precisely regulated and PAOs’ dominant position in carbon source competition is strengthened， thereby enhancing the enrichment of PAOs and the optimization of their metabolism. This breakthrough not only overcomes the low C/P limitation but also underscores the fundamental advantage of S2EBPR. Furthermore， the discussion delves into the critical operational and environmental parameters influencing its efficacy， offering a foundation for precise process management. Looking ahead， the synergistic development of S2EBPR alongside emerging water treatment technologies holds promise for simultaneously efficient nitrogen and phosphorus removal in wastewater treatment， thereby furnishing technical insights for fostering sustainable resource recycling practices.
The challenge of limited phosphorus removal efficiency in low-carbon municipal wastewater is addressed by the innovative side-stream enhanced biological phosphorus removal （S2EBPR） process，which has garnered significant attention. Recent research highlights the core mechanism rooted in the metabolic traits of phosphorus accumulating organisms （PAOs）， pivotal for effective phosphorus removal. However， conventional enhanced biological phosphorus removal （EBPR） processes face constraints under low C/P conditions， where the scarcity of carbon source weakens PAOs’ competitive edge， directly impeding phosphorus removal efficiency. Consequently， S2EBPR establishes a side-stream sludge fermentation unit， through which anaerobic fermentation conditions are precisely regulated and PAOs’ dominant position in carbon source competition is strengthened， thereby enhancing the enrichment of PAOs and the optimization of their metabolism. This breakthrough not only overcomes the low C/P limitation but also underscores the fundamental advantage of S2EBPR. Furthermore， the discussion delves into the critical operational and environmental parameters influencing its efficacy， offering a foundation for precise process management. Looking ahead， the synergistic development of S2EBPR alongside emerging water treatment technologies holds promise for simultaneously efficient nitrogen and phosphorus removal in wastewater treatment， thereby furnishing technical insights for fostering sustainable resource recycling practices.
2026, 44(8): 141-148.
doi: 10.13205/j.hjgc.202608013
Abstract:
To investigate the effects of the algicide combined with submerged plants on inhibiting algal blooms and restoring eutrophic water bodies， as well as the influence of the algicide on the growth and physiology of submerged plants， a compound algicide was prepared using Polyquats-GreatAp126 （PQGA-126）， polyaluminum chloride （PAC）， and red soil. Two submerged plant species， Vallisneria natans and Hydrilla verticillata， were selected for the study. Eutrophic algae-containing water collected from Nanhu Lake in Gongqingcheng City， Jiangxi Province， was used as the research subject. The following treatment groups were established： a control group （CK）， a V. natans group （Vn）， an H. verticillata group （Hv）， a compound algicide group （PPS）， an algicide + V. natans group （PVn）， and an algicide + H. verticillata group （PHv），to conduct indoor static simulation cultivation experiments. The results showed that the combined treatments of the compound algicide with the two submerged plants significantly reduced the concentrations of TN， TP， Chl-a， and water turbidity. This approach substantially decreased the eutrophication level within a short period， and the restoration effect was significantly superior to that of the individual application of either V. natans or H. verticillata. Moreover， the combined application with V. natans resulted in a more pronounced reduction in the comprehensive trophic state index of the water body. Furthermore， the compound algicide significantly enhanced the growth rate of V. natans and the catalase activity of H. verticillata， indicating that V. natans is more adaptable to the compound algicide.
To investigate the effects of the algicide combined with submerged plants on inhibiting algal blooms and restoring eutrophic water bodies， as well as the influence of the algicide on the growth and physiology of submerged plants， a compound algicide was prepared using Polyquats-GreatAp126 （PQGA-126）， polyaluminum chloride （PAC）， and red soil. Two submerged plant species， Vallisneria natans and Hydrilla verticillata， were selected for the study. Eutrophic algae-containing water collected from Nanhu Lake in Gongqingcheng City， Jiangxi Province， was used as the research subject. The following treatment groups were established： a control group （CK）， a V. natans group （Vn）， an H. verticillata group （Hv）， a compound algicide group （PPS）， an algicide + V. natans group （PVn）， and an algicide + H. verticillata group （PHv），to conduct indoor static simulation cultivation experiments. The results showed that the combined treatments of the compound algicide with the two submerged plants significantly reduced the concentrations of TN， TP， Chl-a， and water turbidity. This approach substantially decreased the eutrophication level within a short period， and the restoration effect was significantly superior to that of the individual application of either V. natans or H. verticillata. Moreover， the combined application with V. natans resulted in a more pronounced reduction in the comprehensive trophic state index of the water body. Furthermore， the compound algicide significantly enhanced the growth rate of V. natans and the catalase activity of H. verticillata， indicating that V. natans is more adaptable to the compound algicide.
2026, 44(8): 149-155.
doi: 10.13205/j.hjgc.202608014
Abstract:
Fluoride pollution poses a serious threat to public health worldwide. For dispersed residential areas where high-fluoride groundwater is used as the drinking water source， electroflocculation-based defluorination is a preferable treatment option. However， this technology may have different environmental and economic impacts depending on the water supply scheme adopted， necessitating a comprehensive evaluation to identify the optimal scheme. In this study， three water supply schemes were established： centralized and undifferentiated water supply （S1）， centralized and differentiated water supply （S2）， and distributed and differentiated water supply （S3）. The life cycle environmental impacts and life cycle costs of the three schemes were compared to determine the best option. The results show that： 1） S1 has the largest negative environmental impact， with its environmental impact indicators ranging from 1.4 to 6.7 times those of S2 or S3. The environmental impact is mainly attributable to electrode consumption and electricity usage， particularly when treating large volumes of water. 2） S3 exhibits the lowest water supply cost， achieving a 62% cost reduction compared to S1. In conclusion， the distributed and differentiated water supply scheme （S3） offers both lower life cycle environmental impact and the lowest life cycle cost， making it the most advantageous option for dispersed residential areas.
Fluoride pollution poses a serious threat to public health worldwide. For dispersed residential areas where high-fluoride groundwater is used as the drinking water source， electroflocculation-based defluorination is a preferable treatment option. However， this technology may have different environmental and economic impacts depending on the water supply scheme adopted， necessitating a comprehensive evaluation to identify the optimal scheme. In this study， three water supply schemes were established： centralized and undifferentiated water supply （S1）， centralized and differentiated water supply （S2）， and distributed and differentiated water supply （S3）. The life cycle environmental impacts and life cycle costs of the three schemes were compared to determine the best option. The results show that： 1） S1 has the largest negative environmental impact， with its environmental impact indicators ranging from 1.4 to 6.7 times those of S2 or S3. The environmental impact is mainly attributable to electrode consumption and electricity usage， particularly when treating large volumes of water. 2） S3 exhibits the lowest water supply cost， achieving a 62% cost reduction compared to S1. In conclusion， the distributed and differentiated water supply scheme （S3） offers both lower life cycle environmental impact and the lowest life cycle cost， making it the most advantageous option for dispersed residential areas.
2026, 44(8): 156-168.
doi: 10.13205/j.hjgc.202608015
Abstract:
Inter-basin water diversion projects can profoundly alter the water quality dynamics of receiving basins. Taking the Qincun Reservoir and its downstream reaches in the Huang ze River Basin as a case study， this research quantitatively evaluates the water-quality responses under multiple coordinated management measures. An integrated Environmental Fluid Dynamics Code-Soil and Water Assessment Tool （EFDC-SWAT） modeling framework was established， coupling a two-dimensional hydrodynamic-water-quality model for the reservoir with a hydrology-water-quality model for the downstream reaches. Seven management scenarios were designed to reflect various combinations of point-and non-point-source pollution control strategies. Simulations focused on the spatiotemporal variations in key indicators，total nitrogen （TN）， total phosphorus （TP）， ammonia nitrogen （NH3-N）， and permanganate index （CODMn），and assessed the pollution-load reduction effectiveness of each measure. Comparative analysis using the comprehensive water quality identification index （CWQⅡ） revealed that under Scenario 3 （highest pollution-control standards with lowest diversion volume）， TN and TP concentrations in the reservoir decreased by 80% and 50%， respectively， achieving the Class Ⅱ water-quality standards. Downstream TN and TP levels declined by 36% and 33%，and the CWQⅡ improved from 4.211 to 3.410. Land consolidation contributed 77% and 45% to TN and TP load reductions in the reservoir， respectively， while a 20% reduction in diversion volume was most effective in improving downstream TN （>50%）. These results demonstrate that the coupled EFDC-SWAT model effectively elucidates the mechanisms through which inter-basin water diversion influences the water quality in supply-area. Moreover， synergistic point-and non-point-source controls exhibit a nonlinear enhancement effect on overall water-quality improvement.
Inter-basin water diversion projects can profoundly alter the water quality dynamics of receiving basins. Taking the Qincun Reservoir and its downstream reaches in the Huang ze River Basin as a case study， this research quantitatively evaluates the water-quality responses under multiple coordinated management measures. An integrated Environmental Fluid Dynamics Code-Soil and Water Assessment Tool （EFDC-SWAT） modeling framework was established， coupling a two-dimensional hydrodynamic-water-quality model for the reservoir with a hydrology-water-quality model for the downstream reaches. Seven management scenarios were designed to reflect various combinations of point-and non-point-source pollution control strategies. Simulations focused on the spatiotemporal variations in key indicators，total nitrogen （TN）， total phosphorus （TP）， ammonia nitrogen （NH3-N）， and permanganate index （CODMn），and assessed the pollution-load reduction effectiveness of each measure. Comparative analysis using the comprehensive water quality identification index （CWQⅡ） revealed that under Scenario 3 （highest pollution-control standards with lowest diversion volume）， TN and TP concentrations in the reservoir decreased by 80% and 50%， respectively， achieving the Class Ⅱ water-quality standards. Downstream TN and TP levels declined by 36% and 33%，and the CWQⅡ improved from 4.211 to 3.410. Land consolidation contributed 77% and 45% to TN and TP load reductions in the reservoir， respectively， while a 20% reduction in diversion volume was most effective in improving downstream TN （>50%）. These results demonstrate that the coupled EFDC-SWAT model effectively elucidates the mechanisms through which inter-basin water diversion influences the water quality in supply-area. Moreover， synergistic point-and non-point-source controls exhibit a nonlinear enhancement effect on overall water-quality improvement.
2026, 44(8): 169-179.
doi: 10.13205/j.hjgc.202608016
Abstract:
With advancing urbanization in China， legacy contaminated sites resulting from discontinued or relocated chemical plants are posing increasingly severe environmental risks to groundwater. This contaminated groundwater presents a substantial threat to human health. In this study， a pesticide-contaminated site was investigated using the Groundwater Modeling System （GMS） software to construct a three-dimensional geological structure model， a groundwater flow model， and a solute transport model. These models were used to simulate the migration mechanisms of three representative contaminants （benzene， chloroform， and vinyl chloride） in aquifers and to evaluate the remediation performance of pump-and-treat technology. The results showed that during the initial contaminant transport phase （within 100 d）， contaminants spread uniformly from leakage sources. Subsequently， between 500 and 2000 days， diffusion evolved into elliptical patterns along the southeast-northwest groundwater flow direction， with maximum migration distances increasing to 154.5 m （benzene）， 130.5 m （chloroform）， and 165.2 m （vinyl chloride）， and diffusion areas reaching 18117.4 m2， 13928.5 m2， and 25043.2 m2， respectively. The peak concentrations decreased over time and distance， with benzene decreasing from 53.3 mg/L to 13.0 mg/L （a 75.6% reduction）， chloroform dropping from 112.0 mg/L to 20.0 mg/L （an 82.1% reduction）， and vinyl chloride declining from 128.0 mg/L to 24.0 mg/L （an 81.3% reduction）. For the pump-and-treat remediation approach， the dynamic pumping scheme was simulated. At a simulation time of 400 days， the contaminant plume areas of benzene， chloroform， and vinyl chloride were reduced by 85.8%， 78.0%， and 85.9%， respectively， while their peak concentrations decreased by approximately 90.2%， 82.1%， and 93.8%. Within the 500-day remediation period， all contaminant concentrations dropped below remediation target values. The total pumping volumes were 94500 m3， 60000 m3， and 72000 m3， respectively. Combining pump-and-treat with Fenton reagent （3% dosage） effectively treated the extracted groundwater. This study demonstrates that numerical simulation optimizes contamination delineation and pumping strategies， offering a cost-efficient technical pathway for similar sites.
With advancing urbanization in China， legacy contaminated sites resulting from discontinued or relocated chemical plants are posing increasingly severe environmental risks to groundwater. This contaminated groundwater presents a substantial threat to human health. In this study， a pesticide-contaminated site was investigated using the Groundwater Modeling System （GMS） software to construct a three-dimensional geological structure model， a groundwater flow model， and a solute transport model. These models were used to simulate the migration mechanisms of three representative contaminants （benzene， chloroform， and vinyl chloride） in aquifers and to evaluate the remediation performance of pump-and-treat technology. The results showed that during the initial contaminant transport phase （within 100 d）， contaminants spread uniformly from leakage sources. Subsequently， between 500 and 2000 days， diffusion evolved into elliptical patterns along the southeast-northwest groundwater flow direction， with maximum migration distances increasing to 154.5 m （benzene）， 130.5 m （chloroform）， and 165.2 m （vinyl chloride）， and diffusion areas reaching 18117.4 m2， 13928.5 m2， and 25043.2 m2， respectively. The peak concentrations decreased over time and distance， with benzene decreasing from 53.3 mg/L to 13.0 mg/L （a 75.6% reduction）， chloroform dropping from 112.0 mg/L to 20.0 mg/L （an 82.1% reduction）， and vinyl chloride declining from 128.0 mg/L to 24.0 mg/L （an 81.3% reduction）. For the pump-and-treat remediation approach， the dynamic pumping scheme was simulated. At a simulation time of 400 days， the contaminant plume areas of benzene， chloroform， and vinyl chloride were reduced by 85.8%， 78.0%， and 85.9%， respectively， while their peak concentrations decreased by approximately 90.2%， 82.1%， and 93.8%. Within the 500-day remediation period， all contaminant concentrations dropped below remediation target values. The total pumping volumes were 94500 m3， 60000 m3， and 72000 m3， respectively. Combining pump-and-treat with Fenton reagent （3% dosage） effectively treated the extracted groundwater. This study demonstrates that numerical simulation optimizes contamination delineation and pumping strategies， offering a cost-efficient technical pathway for similar sites.
2026, 44(8): 180-187.
doi: 10.13205/j.hjgc.202608017
Abstract:
Carbon monoxide （CO） is emitted during high-carbon ferrochrome production. However， measured CO emission factor data for different furnace types and process stages remain limited， constraining the accuracy of emission inventory compilation and pollution reduction assessments for the ferroalloy industry. To address the lack of basic CO emission data for high-carbon ferrochrome production， this study selected four typical production facilities in Ulanqab， Inner Mongolia Autonomous Region， China， including two semi-closed submerged arc furnaces and two closed submerged arc furnaces. A combined method integrating manual monitoring and continuous emission monitoring system （CEMS） data was applied. A characteristic ratio between CO and NO x concentrations was established， and continuous monitoring data were used to calculate CO emissions and product-based emission factors. The results indicated that the CO emission factors of semi-closed submerged arc furnace facilities A and B were 7.06 kg/t and 3.66 kg/t， respectively， while those of the associated pelletizing processes of closed submerged arc furnace facilities C and D were 1.41 kg/t and 0.51 kg/t， respectively. The CO emission level of semi-closed submerged arc furnaces was significantly higher than that of closed submerged arc furnaces. This study provides measured evidence for CO emission accounting and the development of furnace-type-specific emission factors in the high-carbon ferrochrome industry.
Carbon monoxide （CO） is emitted during high-carbon ferrochrome production. However， measured CO emission factor data for different furnace types and process stages remain limited， constraining the accuracy of emission inventory compilation and pollution reduction assessments for the ferroalloy industry. To address the lack of basic CO emission data for high-carbon ferrochrome production， this study selected four typical production facilities in Ulanqab， Inner Mongolia Autonomous Region， China， including two semi-closed submerged arc furnaces and two closed submerged arc furnaces. A combined method integrating manual monitoring and continuous emission monitoring system （CEMS） data was applied. A characteristic ratio between CO and NO x concentrations was established， and continuous monitoring data were used to calculate CO emissions and product-based emission factors. The results indicated that the CO emission factors of semi-closed submerged arc furnace facilities A and B were 7.06 kg/t and 3.66 kg/t， respectively， while those of the associated pelletizing processes of closed submerged arc furnace facilities C and D were 1.41 kg/t and 0.51 kg/t， respectively. The CO emission level of semi-closed submerged arc furnaces was significantly higher than that of closed submerged arc furnaces. This study provides measured evidence for CO emission accounting and the development of furnace-type-specific emission factors in the high-carbon ferrochrome industry.
2026, 44(8): 188-202.
doi: 10.13205/j.hjgc.202608018
Abstract:
Chlorinated volatile organic compounds （CVOCs） are volatile， difficult to degrade， and highly toxic， posing serious threats to the atmospheric environment and human health. Catalytic oxidation is currently one of the mainstream methods for CVOCs abatement， owing to its high efficiency， safety， and economic feasibility， and its key aspect lies in the design and development of high-performance catalysts. In the catalytic oxidation of CVOCs， the poisoning effect of chlorine species on catalysts severely restricts catalytic performance. Ru-based catalysts， which exhibit excellent catalytic oxidation activity toward CVOCs and favorable chlorine-resistant performance， have been widely studied in recent years. This paper reviews the latest research progress on Ru-based catalysts for the catalytic oxidation of CVOCs. The mechanism of catalytic oxidation of CVOCs by Ru-based catalysts is elucidated through a systematic analysis of the relevant literature. Furthermore， the strategies for the design and structural regulation of Ru-based catalysts are outlined from the perspectives of active components， supports， and surface modification. Finally， novel preparation methods for Ru-based catalysts and the influence of reaction components on catalytic performance are summarized. Future research directions in this field are also prospected， aiming to provide a reference for the subsequent design and development of high-performance Ru-based catalysts suitable for complex operating conditions.
Chlorinated volatile organic compounds （CVOCs） are volatile， difficult to degrade， and highly toxic， posing serious threats to the atmospheric environment and human health. Catalytic oxidation is currently one of the mainstream methods for CVOCs abatement， owing to its high efficiency， safety， and economic feasibility， and its key aspect lies in the design and development of high-performance catalysts. In the catalytic oxidation of CVOCs， the poisoning effect of chlorine species on catalysts severely restricts catalytic performance. Ru-based catalysts， which exhibit excellent catalytic oxidation activity toward CVOCs and favorable chlorine-resistant performance， have been widely studied in recent years. This paper reviews the latest research progress on Ru-based catalysts for the catalytic oxidation of CVOCs. The mechanism of catalytic oxidation of CVOCs by Ru-based catalysts is elucidated through a systematic analysis of the relevant literature. Furthermore， the strategies for the design and structural regulation of Ru-based catalysts are outlined from the perspectives of active components， supports， and surface modification. Finally， novel preparation methods for Ru-based catalysts and the influence of reaction components on catalytic performance are summarized. Future research directions in this field are also prospected， aiming to provide a reference for the subsequent design and development of high-performance Ru-based catalysts suitable for complex operating conditions.
2026, 44(8): 203-210.
doi: 10.13205/j.hjgc.202608019
Abstract:
In the semi-dry desulfurization process of the circulating fluidized bed， the flow field of the reactor usually affects its desulfurization efficiency. Under the condition of constant flue gas velocity in the Venturi tube， the measure for adapting to different flue gas load variation by setting bypass valves across the Venturi tube section between the reactor inlet and the diffusion section can not only optimize the flow field inside the reactor， but also improve the desulfurization efficiency. In this paper， through numerical simulation， it was concluded that， when the flue gas load of the reactor changes， the opening of the bypass valves should be no less than 50%， and the number of bypass pipelines should be no less than 2， to ensure the uniform flow field distribution in the reactor. When the flue gas load was 100%， the pressure loss of the reactor was 911 Pa. With the flue gas load decrease， the pressure loss of the empty reactor was about 500 Pa. In summary， the circulating fluidized bed reactor with a bypass through the introduction and optimized regulation of the bypass structure， can achieve uniform and stable flow fields as well as low operating pressure losses within a wide flue gas load range of 50% to 100%. This provides an effective solution for enhancing desulfurization efficiency and operational adaptability in practical engineering applications.
In the semi-dry desulfurization process of the circulating fluidized bed， the flow field of the reactor usually affects its desulfurization efficiency. Under the condition of constant flue gas velocity in the Venturi tube， the measure for adapting to different flue gas load variation by setting bypass valves across the Venturi tube section between the reactor inlet and the diffusion section can not only optimize the flow field inside the reactor， but also improve the desulfurization efficiency. In this paper， through numerical simulation， it was concluded that， when the flue gas load of the reactor changes， the opening of the bypass valves should be no less than 50%， and the number of bypass pipelines should be no less than 2， to ensure the uniform flow field distribution in the reactor. When the flue gas load was 100%， the pressure loss of the reactor was 911 Pa. With the flue gas load decrease， the pressure loss of the empty reactor was about 500 Pa. In summary， the circulating fluidized bed reactor with a bypass through the introduction and optimized regulation of the bypass structure， can achieve uniform and stable flow fields as well as low operating pressure losses within a wide flue gas load range of 50% to 100%. This provides an effective solution for enhancing desulfurization efficiency and operational adaptability in practical engineering applications.
2026, 44(8): 211-219.
doi: 10.13205/j.hjgc.202608020
Abstract:
This paper summarized the overall progress and achievements of the collaborative innovation pilots aimed at reducing pollution and carbon emissions， identified existing challenges， and proposed actionable insights. Currently， the pilots have demonstrated smooth progress and notable phased outcomes. Most pilot units have actively promoted breakthroughs in institutional and mechanism innovations， achieved substantial advancements in key sectors and critical areas， and implemented a series of synergistic measures， yielding institutional innovations and replicable practices. However， challenges persist， including fragmented interdepartmental collaboration， insufficient alignment of management systems， funding shortages for synergistic projects， and inadequate technological support. Recommendations included intensifying awareness campaigns on synergistic efficiency， establishing coordinated promotion mechanisms， accelerating the implementation of synergistic management systems， advancing core technology R&D， conducting progress evaluations， and amplifying publicity to foster broader adoption. Simultaneously， recommendations were proposed for expanding the second batch of pilot work， focusing on advancement strategies， types of pilot programs， and selection methods.
This paper summarized the overall progress and achievements of the collaborative innovation pilots aimed at reducing pollution and carbon emissions， identified existing challenges， and proposed actionable insights. Currently， the pilots have demonstrated smooth progress and notable phased outcomes. Most pilot units have actively promoted breakthroughs in institutional and mechanism innovations， achieved substantial advancements in key sectors and critical areas， and implemented a series of synergistic measures， yielding institutional innovations and replicable practices. However， challenges persist， including fragmented interdepartmental collaboration， insufficient alignment of management systems， funding shortages for synergistic projects， and inadequate technological support. Recommendations included intensifying awareness campaigns on synergistic efficiency， establishing coordinated promotion mechanisms， accelerating the implementation of synergistic management systems， advancing core technology R&D， conducting progress evaluations， and amplifying publicity to foster broader adoption. Simultaneously， recommendations were proposed for expanding the second batch of pilot work， focusing on advancement strategies， types of pilot programs， and selection methods.
2026, 44(8): 220-230.
doi: 10.13205/j.hjgc.202608021
Abstract:
To address the significant increase in fine particulate matter （PM2.5） and its chemical component concentrations caused by the concentrated setting-off of fireworks and firecrackers during the Spring Festival in Yancheng City， this study introduced the Bayesian-optimized XGBoost model （BO-XGBoost） based on PM2.5， particulate component， and meteorological observation data in Yancheng City， to quantitatively assess the contribution of fireworks and firecracker setting-off to changes in PM2.5 and its components. The results showed that the concentrated setting-off of fireworks and firecrackers exerted significantly differentiated effects on various pollutants. Among water-soluble ions， K+ and Mg2+ were core characteristic tracers， with their concentrations reaching 15.89 and 20.08 times their baseline levels， respectively， on Lunar New Year’s Eve， directly reflecting high-intensity emissions from setting-off activities. Secondary conversion ions such as SO42- and NO3- showed sustained high contributions on both Lunar New Year’s Eve and the fifth day of the first lunar month， reflecting the cumulative effect of primary pollutants from setting-off after atmospheric chemical transformation. Among inorganic elements， K， Ba， and Sr were core characteristic tracers， with concentrations showing explosive growth on Lunar New Year’s Eve， serving as direct "fingerprints" of fireworks and firecracker setting-off. Elements such as Pb and Mn were also significantly affected by setting-off， with their concentration fluctuations reflecting direct heavy metal emissions. Temporal comparisons indicated that emission intensity on Lunar New Year’s Eve was significantly higher than that on the fifth day of the first lunar month， and the proportional contribution of secondary conversion processes to pollutant concentrations increased on the fifth day. This study achieved accurate quantification of setting-off contributions through a data-driven model， clarified the pollution fingerprint characteristics and temporal differentiation patterns of fireworks and firecracker setting-off. These findings provide a scientific basis and technical support for air quality management and the optimization of setting-off policies during the Spring Festival in Yancheng City.
To address the significant increase in fine particulate matter （PM2.5） and its chemical component concentrations caused by the concentrated setting-off of fireworks and firecrackers during the Spring Festival in Yancheng City， this study introduced the Bayesian-optimized XGBoost model （BO-XGBoost） based on PM2.5， particulate component， and meteorological observation data in Yancheng City， to quantitatively assess the contribution of fireworks and firecracker setting-off to changes in PM2.5 and its components. The results showed that the concentrated setting-off of fireworks and firecrackers exerted significantly differentiated effects on various pollutants. Among water-soluble ions， K+ and Mg2+ were core characteristic tracers， with their concentrations reaching 15.89 and 20.08 times their baseline levels， respectively， on Lunar New Year’s Eve， directly reflecting high-intensity emissions from setting-off activities. Secondary conversion ions such as SO42- and NO3- showed sustained high contributions on both Lunar New Year’s Eve and the fifth day of the first lunar month， reflecting the cumulative effect of primary pollutants from setting-off after atmospheric chemical transformation. Among inorganic elements， K， Ba， and Sr were core characteristic tracers， with concentrations showing explosive growth on Lunar New Year’s Eve， serving as direct "fingerprints" of fireworks and firecracker setting-off. Elements such as Pb and Mn were also significantly affected by setting-off， with their concentration fluctuations reflecting direct heavy metal emissions. Temporal comparisons indicated that emission intensity on Lunar New Year’s Eve was significantly higher than that on the fifth day of the first lunar month， and the proportional contribution of secondary conversion processes to pollutant concentrations increased on the fifth day. This study achieved accurate quantification of setting-off contributions through a data-driven model， clarified the pollution fingerprint characteristics and temporal differentiation patterns of fireworks and firecracker setting-off. These findings provide a scientific basis and technical support for air quality management and the optimization of setting-off policies during the Spring Festival in Yancheng City.
2026, 44(8): 231-237.
doi: 10.13205/j.hjgc.202608022
Abstract:
Since China's first domestic sludge incineration project was completed and put into operation at the Shidongkou Wastewater Treatment Plant in Shanghai in 2004， this technology has been gradually adopted and promoted in key economically developed cities in China. However， as urban wastewater treatment facilities are often planned and constructed in a decentralized manner and employ diverse process technologies， the sludge characterization is changeable. In contrast， the planning and construction of sludge mono-incineration facilities are relatively concentrated， sludges with different properties have brought great impacts on the planning and site selection， project decision-making， engineering design， and economic stable operation of drying and incineration facilities. Taking the planning and engineering design of a sludge incineration plant in Qingdao as an example， the properties of sludge from major wastewater treatment plants in the urban area currently vary significantly due to differences in wastewater characteristics and treatment processes. Based on the data of sludge moisture content， organic matter content and other key indicators from each wastewater treatment plant， theoretical research was carried out to construct an energy balance calculation model. Based on this model， a set of sludge distribution plans was formulated， and a simplified cost calculation method for sludge with different properties was developed， which provides a reference for the differentiated pricing and rational allocation of sludge with multiple properties in sludge drying and incineration projects. Meanwhile， combined with the differences in sludge moisture content， and aiming at the two types of received sludge properties （conventional dewatering and deep dewatering）， a comparative analysis was carried out on the whole-process costs and carbon emissions from the sludge's origin to its final disposal from the perspective of "wastewater treatment plant + sludge incineration"， to provide support for the overall planning and process optimization of urban sludge treatment and disposal.
Since China's first domestic sludge incineration project was completed and put into operation at the Shidongkou Wastewater Treatment Plant in Shanghai in 2004， this technology has been gradually adopted and promoted in key economically developed cities in China. However， as urban wastewater treatment facilities are often planned and constructed in a decentralized manner and employ diverse process technologies， the sludge characterization is changeable. In contrast， the planning and construction of sludge mono-incineration facilities are relatively concentrated， sludges with different properties have brought great impacts on the planning and site selection， project decision-making， engineering design， and economic stable operation of drying and incineration facilities. Taking the planning and engineering design of a sludge incineration plant in Qingdao as an example， the properties of sludge from major wastewater treatment plants in the urban area currently vary significantly due to differences in wastewater characteristics and treatment processes. Based on the data of sludge moisture content， organic matter content and other key indicators from each wastewater treatment plant， theoretical research was carried out to construct an energy balance calculation model. Based on this model， a set of sludge distribution plans was formulated， and a simplified cost calculation method for sludge with different properties was developed， which provides a reference for the differentiated pricing and rational allocation of sludge with multiple properties in sludge drying and incineration projects. Meanwhile， combined with the differences in sludge moisture content， and aiming at the two types of received sludge properties （conventional dewatering and deep dewatering）， a comparative analysis was carried out on the whole-process costs and carbon emissions from the sludge's origin to its final disposal from the perspective of "wastewater treatment plant + sludge incineration"， to provide support for the overall planning and process optimization of urban sludge treatment and disposal.
2026, 44(8): 238-246.
doi: 10.13205/j.hjgc.202608023
Abstract:
Zinc-containing steel dust sludge is a by-product generated during the steelmaking process， which contains a large amount of Cl， as well as elements such as Fe， Zn， K， and Na. During its recycling process in the steel production cycle， Cl accumulates， leading to unstable sintering operation and severe corrosion of blast furnace linings. This paper investigated the water leaching dechlorination of zinc-containing steel dust sludge. The results showed that the Cl leaching rate reached 87% under the conditions of a liquid-to-solid ratio of 5 mL/g， a leaching temperature of 70 ℃， a leaching time of 60 min， and a rotation speed of 160 r/min. Additionally， at a liquid-to-solid ratio of 6 mL/g and room temperature， the Cl leaching rate reached 90% after 45 min of three-stage countercurrent water washing. The water-washing process reduced the leaching toxicity of metals in zinc-containing steel dust sludge to a certain extent. The research results provide theoretical and technical support for the dechlorination of zinc-containing steel dust sludge.
Zinc-containing steel dust sludge is a by-product generated during the steelmaking process， which contains a large amount of Cl， as well as elements such as Fe， Zn， K， and Na. During its recycling process in the steel production cycle， Cl accumulates， leading to unstable sintering operation and severe corrosion of blast furnace linings. This paper investigated the water leaching dechlorination of zinc-containing steel dust sludge. The results showed that the Cl leaching rate reached 87% under the conditions of a liquid-to-solid ratio of 5 mL/g， a leaching temperature of 70 ℃， a leaching time of 60 min， and a rotation speed of 160 r/min. Additionally， at a liquid-to-solid ratio of 6 mL/g and room temperature， the Cl leaching rate reached 90% after 45 min of three-stage countercurrent water washing. The water-washing process reduced the leaching toxicity of metals in zinc-containing steel dust sludge to a certain extent. The research results provide theoretical and technical support for the dechlorination of zinc-containing steel dust sludge.
2026, 44(8): 247-257.
doi: 10.13205/j.hjgc.202608024
Abstract:
Microbial remediation is one of the widely used remediation techniques in the field of groundwater chromium pollution remediation. Using literature collected from the Web of Science core® database as the data source， CiteSpace， VOSviewer and Pajek bibliometric software were used to analyze the relevant literature in the field of global groundwater microbial remediation in the past 15 years （2010 to 2024） from three aspects： publication volume， keyword analysis， and policy analysis. The development trend and hotspots of research in this field were systematically sorted out. The results showed that there were a total of 441 research papers in the field of groundwater microbial remediation technology， and the trend of publication has been on the rise in the past 15 years. The development of this field can be divided into three stages： The early research stage （2010 to 2016） mainly focused on the basic treatment methods of chromium pollution； the in-depth exploration stage （2017 to 2019） focused on the intrinsic mechanisms of microbial remediation processes； the expanded research stage （2020 to 2024） shifted its focus to remediation process optimization. Through literature analysis， it is revealed that biological adsorption and biological reduction are the main mechanisms of chromium contaminated microbial remediation. The impact mechanism of four environmental factors， including temperature， pH， initial chromium concentration and reaction time， on microbial remediation was determined through correlation analysis and principal component analysis. Temperature was identified as the key factor affecting remediation efficiency， and the removal efficiency and mechanism of different dominant bacterial strains were summarized， providing reference for the selection of bacterial strains in practical applications. In the future， it is recommended to focus on the synergistic effects of microbial communities， the combination of nanomaterials， and the optimization of environmental conditions to enhance the microbial remediation efficiency of chromium pollution.
Microbial remediation is one of the widely used remediation techniques in the field of groundwater chromium pollution remediation. Using literature collected from the Web of Science core® database as the data source， CiteSpace， VOSviewer and Pajek bibliometric software were used to analyze the relevant literature in the field of global groundwater microbial remediation in the past 15 years （2010 to 2024） from three aspects： publication volume， keyword analysis， and policy analysis. The development trend and hotspots of research in this field were systematically sorted out. The results showed that there were a total of 441 research papers in the field of groundwater microbial remediation technology， and the trend of publication has been on the rise in the past 15 years. The development of this field can be divided into three stages： The early research stage （2010 to 2016） mainly focused on the basic treatment methods of chromium pollution； the in-depth exploration stage （2017 to 2019） focused on the intrinsic mechanisms of microbial remediation processes； the expanded research stage （2020 to 2024） shifted its focus to remediation process optimization. Through literature analysis， it is revealed that biological adsorption and biological reduction are the main mechanisms of chromium contaminated microbial remediation. The impact mechanism of four environmental factors， including temperature， pH， initial chromium concentration and reaction time， on microbial remediation was determined through correlation analysis and principal component analysis. Temperature was identified as the key factor affecting remediation efficiency， and the removal efficiency and mechanism of different dominant bacterial strains were summarized， providing reference for the selection of bacterial strains in practical applications. In the future， it is recommended to focus on the synergistic effects of microbial communities， the combination of nanomaterials， and the optimization of environmental conditions to enhance the microbial remediation efficiency of chromium pollution.
2026, 44(8): 258-270.
doi: 10.13205/j.hjgc.202608025
Abstract:
To evaluate the characteristics of heavy metal contamination in desert lakes and the associated health risks， this study took Hongjiannao Lake in Northern Shaanxi as the research object and analyzed the concentrations of seven heavy metals （Hg， Pb， Cu， Zn， Cd， Cr， and As） in the water body from 2013 to 2024. The absolute principal component score-multiple linear regression （APCS-MLR） model was employed for quantitative source apportionment to identify contamination sources and their contribution rates. Combined with a health risk assessment model， the levels of non-carcinogenic and carcinogenic health risks to humans were revealed. The results indicated that the average concentrations of the seven heavy metals in Hongjiannao Lake did not exceed the background values， although 28.57% of the sampling points showed As concentrations exceeding the background value， with a maximum exceedance factor of 1.92. The average total concentration of the seven heavy metals decreased from 112.51 μg/L in 2013， to 2016 to 58.80 μg/L in 2017 to 2024， primarily due to the local government's policy of closing small coal mines in 2016 and the ecological restoration project in the coal mining area around the Hongjiannao Lake 4A-level tourist attraction. The water body in the study area was influenced by industrial， traffic， agricultural， and natural sources， with contribution rates of 35.44%， 16.23%， 24.67%， and 23.65%， respectively， indicating that industrial sources were the primary contributors to heavy metal contamination， followed by agricultural sources. The health risk assessment results showed that non-carcinogenic health risks were negligible， while carcinogenic risks exceeded the alert value （1.00E-4）， with higher risks for adults than for children. Oral ingestion was the primary exposure pathway， with As and Cd being the key control elements， showing exceedance rates of 100% and 16.67%， respectively. These findings provide a theoretical basis for health risk prevention and control for surrounding residents and for environmental quality management in the lake area.
To evaluate the characteristics of heavy metal contamination in desert lakes and the associated health risks， this study took Hongjiannao Lake in Northern Shaanxi as the research object and analyzed the concentrations of seven heavy metals （Hg， Pb， Cu， Zn， Cd， Cr， and As） in the water body from 2013 to 2024. The absolute principal component score-multiple linear regression （APCS-MLR） model was employed for quantitative source apportionment to identify contamination sources and their contribution rates. Combined with a health risk assessment model， the levels of non-carcinogenic and carcinogenic health risks to humans were revealed. The results indicated that the average concentrations of the seven heavy metals in Hongjiannao Lake did not exceed the background values， although 28.57% of the sampling points showed As concentrations exceeding the background value， with a maximum exceedance factor of 1.92. The average total concentration of the seven heavy metals decreased from 112.51 μg/L in 2013， to 2016 to 58.80 μg/L in 2017 to 2024， primarily due to the local government's policy of closing small coal mines in 2016 and the ecological restoration project in the coal mining area around the Hongjiannao Lake 4A-level tourist attraction. The water body in the study area was influenced by industrial， traffic， agricultural， and natural sources， with contribution rates of 35.44%， 16.23%， 24.67%， and 23.65%， respectively， indicating that industrial sources were the primary contributors to heavy metal contamination， followed by agricultural sources. The health risk assessment results showed that non-carcinogenic health risks were negligible， while carcinogenic risks exceeded the alert value （1.00E-4）， with higher risks for adults than for children. Oral ingestion was the primary exposure pathway， with As and Cd being the key control elements， showing exceedance rates of 100% and 16.67%， respectively. These findings provide a theoretical basis for health risk prevention and control for surrounding residents and for environmental quality management in the lake area.
2026, 44(8): 271-280.
doi: 10.13205/j.hjgc.202608026
Abstract:
Biochar and microbial inoculants are widely used for agricultural soil amendment. To better investigate the effects of different types of straw-derived biochar and microbial inoculants， applied individually or in combination， on nitrogen transformation in upland soil， this study established six treatment groups for a laboratory-based static incubation experiment， to determine their impacts on soil nitrogen cycle. The experimental results demonstrated that applying rice straw biochar increased the soil nitrate nitrogen content by 148.74% to 152.68%， significantly enhancing soil nitrification. Furthermore， its combined application with microbial inoculants increased the average net soil nitrogen mineralization rate by 77.28% to 99.38%. Conversely， rapeseed straw biochar decreased the soil nitrate nitrogen content by 51.66% to 57.61%， and its combined application with the inoculants reduced the average net nitrogen mineralization rate by 82.07% to 84.73%. Treatments S， Y， SJ， and YJ promoted the synthesis of soil microbial biomass nitrogen （MBN）. Compared with CK， treatments S and Y increased MBN by 2.02- and 2.20-fold， respectively， while the combined treatments （SJ， YJ） further increased the MBN content by 103.26% to 149.44%. Thus， different types of straw biochar exerted inconsistent effects on soil nitrification and net nitrogen mineralization， while the combined treatments exhibited a synergistic effect on MBN production. For the comprehensive improvement and utilization of upland soil， selecting the YJ treatment proved to be the optimal amendment strategy， effectively reducing the risk of soil inorganic nitrogen loss while enhancing microbial nitrogen activity.
Biochar and microbial inoculants are widely used for agricultural soil amendment. To better investigate the effects of different types of straw-derived biochar and microbial inoculants， applied individually or in combination， on nitrogen transformation in upland soil， this study established six treatment groups for a laboratory-based static incubation experiment， to determine their impacts on soil nitrogen cycle. The experimental results demonstrated that applying rice straw biochar increased the soil nitrate nitrogen content by 148.74% to 152.68%， significantly enhancing soil nitrification. Furthermore， its combined application with microbial inoculants increased the average net soil nitrogen mineralization rate by 77.28% to 99.38%. Conversely， rapeseed straw biochar decreased the soil nitrate nitrogen content by 51.66% to 57.61%， and its combined application with the inoculants reduced the average net nitrogen mineralization rate by 82.07% to 84.73%. Treatments S， Y， SJ， and YJ promoted the synthesis of soil microbial biomass nitrogen （MBN）. Compared with CK， treatments S and Y increased MBN by 2.02- and 2.20-fold， respectively， while the combined treatments （SJ， YJ） further increased the MBN content by 103.26% to 149.44%. Thus， different types of straw biochar exerted inconsistent effects on soil nitrification and net nitrogen mineralization， while the combined treatments exhibited a synergistic effect on MBN production. For the comprehensive improvement and utilization of upland soil， selecting the YJ treatment proved to be the optimal amendment strategy， effectively reducing the risk of soil inorganic nitrogen loss while enhancing microbial nitrogen activity.
2026, 44(8): 281-289.
doi: 10.13205/j.hjgc.202608027
Abstract:
A large number of industrial enterprises in China have relocated from their former sites， leaving behind soil contamination problems， particularly volatile organic compounds such as BTEX， whose environmental migration and health risks have attracted significant attention. Owing to the special hydrogeological conditions of coastal plains—including a high groundwater table and interbedded sedimentary strata—the spatial distribution and migration patterns of contaminants in these areas differ markedly from those in inland regions. This study took a decommissioned resin plant site in the coastal plain of the Yangtze River Delta as the research object and systematically investigated the spatial distribution， migration patterns， and health risks of BTEX contamination in the soil. The results showed that seven BTEX compounds were detected in the soil， with detection rates ranging from 24.3% to 47.1%. Among them， the maximum concentrations of benzene， ethylbenzene， and m/p-xylene exceeded the screening values for Class I construction land in China. The contaminant plume was mainly distributed in the product warehouse area in the southern part of the site， while the potential pollution source was located in the upstream wastewater treatment unit， presenting a “source-sink” spatial mismatch phenomenon. The vertical distribution of contaminants exhibited a differentiated pattern of “shallow-layer volatilization， middle-layer enrichment， and deep-layer retardation”. Significant enrichment occurred in the silty clay layer at depths of 3 to 6 m， while concentrations sharply decreased in the mucky clay layer. MIP multi-parameter detection showed that major components such as benzene and toluene migrated overall， whereas chlorobenzene exhibited delayed migration owing to its strong adsorption affinity. Benzene was the most prominent contaminant of concern for health risks： its carcinogenic risks （up to 7.42×10-4） and non-carcinogenic hazard quotients （up to 38.24） both exceeded acceptable levels. Inhalation of gaseous contaminants from underlying soil into indoor air contributed over 87% of the total risk of benzene， making it the dominant exposure pathway. This study reveals the unique characteristics of contaminant migration and risk formation under conditions of a high water table and interbedded strata in coastal plains. These findings can provide a scientific basis for the accurate investigation， risk assessment， and remediation of similar industrially contaminated sites.
A large number of industrial enterprises in China have relocated from their former sites， leaving behind soil contamination problems， particularly volatile organic compounds such as BTEX， whose environmental migration and health risks have attracted significant attention. Owing to the special hydrogeological conditions of coastal plains—including a high groundwater table and interbedded sedimentary strata—the spatial distribution and migration patterns of contaminants in these areas differ markedly from those in inland regions. This study took a decommissioned resin plant site in the coastal plain of the Yangtze River Delta as the research object and systematically investigated the spatial distribution， migration patterns， and health risks of BTEX contamination in the soil. The results showed that seven BTEX compounds were detected in the soil， with detection rates ranging from 24.3% to 47.1%. Among them， the maximum concentrations of benzene， ethylbenzene， and m/p-xylene exceeded the screening values for Class I construction land in China. The contaminant plume was mainly distributed in the product warehouse area in the southern part of the site， while the potential pollution source was located in the upstream wastewater treatment unit， presenting a “source-sink” spatial mismatch phenomenon. The vertical distribution of contaminants exhibited a differentiated pattern of “shallow-layer volatilization， middle-layer enrichment， and deep-layer retardation”. Significant enrichment occurred in the silty clay layer at depths of 3 to 6 m， while concentrations sharply decreased in the mucky clay layer. MIP multi-parameter detection showed that major components such as benzene and toluene migrated overall， whereas chlorobenzene exhibited delayed migration owing to its strong adsorption affinity. Benzene was the most prominent contaminant of concern for health risks： its carcinogenic risks （up to 7.42×10-4） and non-carcinogenic hazard quotients （up to 38.24） both exceeded acceptable levels. Inhalation of gaseous contaminants from underlying soil into indoor air contributed over 87% of the total risk of benzene， making it the dominant exposure pathway. This study reveals the unique characteristics of contaminant migration and risk formation under conditions of a high water table and interbedded strata in coastal plains. These findings can provide a scientific basis for the accurate investigation， risk assessment， and remediation of similar industrially contaminated sites.
2026, 44(8): 290-298.
doi: 10.13205/j.hjgc.202608028
Abstract:
The multi-component volatile organic compounds （VOCs） waste gas generated during ship loading operations have a complex composition， typically including methanol， dichloromethane， trichloroethylene， p-xylene， acrylonitrile， benzene， acetonitrile， and other organic compounds， which are difficult to treat under the high-humidity conditions of marine environments. In this study， the above seven typical VOCs were selected as representatives. Three types of molecular sieves with different pore sizes， namely ZSM-5， β-type， and HY， were systematically screened， and their selective adsorption performance for various components was investigated under varying moisture content conditions （0%， 2.5%， and 5%）. The competitive adsorption behavior of an acrylonitrile and p-xylene mixed system on ZSM-5-all-silica and HY-100 molecular sieves was particularly examined. The experimental results showed that： 1） the saturated adsorption capacity of the molecular sieves decreased with increasing moisture content， indicating an obvious competitive adsorption effect between water molecules and VOCs； 2） the selective adsorption of the molecular sieves followed the pore size matching principle： ZSM-5 （pore size： 0.54 to 0.56 nm） was suitable for the adsorption of small C1 to C3 molecules such as dichloromethane， trichloroethylene， acetonitrile， and acrylonitrile （adsorption capacity： 10 to 50 mg/g）； β-type molecular sieves （pore size： 1.1 to 1.2 nm） exhibited the best universality for C3 to C6 molecules； and HY molecular sieves （pore size： 2.16 to 2.76 nm） were more suitable for the adsorption of large C8 molecules such as p-xylene （adsorption capacity： 100 to 120 mg/g）； 3） in multi-component VOCs systems， by optimizing the proportion and arrangement of molecular sieves， the adsorption capacity for different components could be balanced， significantly prolonging the breakthrough time of mixed VOCs and improving the utilization efficiency of the molecular sieves. This study holds theoretical significance and practical value for promoting the engineering application of molecular sieve technology in the treatment of waste gas from ship loading operations and port collection， distribution， and transportation processes， enhancing the treatment efficiency of multi-component VOCs， and reducing emissions of waste gas generated during the transfer of liquid bulk cargo at ports.
The multi-component volatile organic compounds （VOCs） waste gas generated during ship loading operations have a complex composition， typically including methanol， dichloromethane， trichloroethylene， p-xylene， acrylonitrile， benzene， acetonitrile， and other organic compounds， which are difficult to treat under the high-humidity conditions of marine environments. In this study， the above seven typical VOCs were selected as representatives. Three types of molecular sieves with different pore sizes， namely ZSM-5， β-type， and HY， were systematically screened， and their selective adsorption performance for various components was investigated under varying moisture content conditions （0%， 2.5%， and 5%）. The competitive adsorption behavior of an acrylonitrile and p-xylene mixed system on ZSM-5-all-silica and HY-100 molecular sieves was particularly examined. The experimental results showed that： 1） the saturated adsorption capacity of the molecular sieves decreased with increasing moisture content， indicating an obvious competitive adsorption effect between water molecules and VOCs； 2） the selective adsorption of the molecular sieves followed the pore size matching principle： ZSM-5 （pore size： 0.54 to 0.56 nm） was suitable for the adsorption of small C1 to C3 molecules such as dichloromethane， trichloroethylene， acetonitrile， and acrylonitrile （adsorption capacity： 10 to 50 mg/g）； β-type molecular sieves （pore size： 1.1 to 1.2 nm） exhibited the best universality for C3 to C6 molecules； and HY molecular sieves （pore size： 2.16 to 2.76 nm） were more suitable for the adsorption of large C8 molecules such as p-xylene （adsorption capacity： 100 to 120 mg/g）； 3） in multi-component VOCs systems， by optimizing the proportion and arrangement of molecular sieves， the adsorption capacity for different components could be balanced， significantly prolonging the breakthrough time of mixed VOCs and improving the utilization efficiency of the molecular sieves. This study holds theoretical significance and practical value for promoting the engineering application of molecular sieve technology in the treatment of waste gas from ship loading operations and port collection， distribution， and transportation processes， enhancing the treatment efficiency of multi-component VOCs， and reducing emissions of waste gas generated during the transfer of liquid bulk cargo at ports.
