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2025 Vol. 43, No. 11
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2025, 43(11): 1-10.
doi: 10.13205/j.hjgc.202511001
Abstract:
The accurate detection of particle concentration and size distribution is crucial for ensuring the efficient operation of water treatment plants and environmental monitoring. However， in practical environments， various particles are often mixed， making it challenging for existing detection methods to achieve precise measurements in complex particle systems. To address the need for intelligent monitoring in water treatment plants， this study proposed an approach that integrated the electrical sensing zone （ESZ） method with machine learning （ML）， achieving high-precision classification and identification of typical pure-substance particles in water treatment for the first time. By optimizing ESZ acquisition conditions， the optimal parameters were determined as a suction speed of 3 mL/min and a stirring speed of 300 r/min. The formation mechanism of ESZ signals was theoretically analyzed， revealing that multiple factors exist， including fluid velocity， particle diameter， density， and shape， influence waveforms. A pure-substance particle database was constructed based on ESZ， and various machine learning classification algorithms were compared. The support vector machine （SVM） model demonstrated the best performance， achieving an identification accuracy of 95.3% for four pure-substance particles： bubbles， quartz sand， polyethylene terephthalate （PET）， and paramecium. While bubbles and quartz sand were distinguished with excellent accuracy， some confusion remained between PET and paramecium， indicating the need for further algorithm optimization. This study provides a new approach for particle identification， and future work will involve validation in mixed-particle systems， offering technical support for the precision and intelligence of water treatment monitoring.
The accurate detection of particle concentration and size distribution is crucial for ensuring the efficient operation of water treatment plants and environmental monitoring. However， in practical environments， various particles are often mixed， making it challenging for existing detection methods to achieve precise measurements in complex particle systems. To address the need for intelligent monitoring in water treatment plants， this study proposed an approach that integrated the electrical sensing zone （ESZ） method with machine learning （ML）， achieving high-precision classification and identification of typical pure-substance particles in water treatment for the first time. By optimizing ESZ acquisition conditions， the optimal parameters were determined as a suction speed of 3 mL/min and a stirring speed of 300 r/min. The formation mechanism of ESZ signals was theoretically analyzed， revealing that multiple factors exist， including fluid velocity， particle diameter， density， and shape， influence waveforms. A pure-substance particle database was constructed based on ESZ， and various machine learning classification algorithms were compared. The support vector machine （SVM） model demonstrated the best performance， achieving an identification accuracy of 95.3% for four pure-substance particles： bubbles， quartz sand， polyethylene terephthalate （PET）， and paramecium. While bubbles and quartz sand were distinguished with excellent accuracy， some confusion remained between PET and paramecium， indicating the need for further algorithm optimization. This study provides a new approach for particle identification， and future work will involve validation in mixed-particle systems， offering technical support for the precision and intelligence of water treatment monitoring.
2025, 43(11): 11-20.
doi: 10.13205/j.hjgc.202511002
Abstract:
Urban rivers， as an essential component of the urban ecosystem， play a crucial role in urban development， and understanding the variation of water environment and conducting water quality assessments are improtant for urban planning and environmental protection policies formulation. The spatial and temporal variation in water quality of urban rivers in Yangpu District， Shanghai， China， were analyzed based on the monthly data of 18 monitoring sites from 2018 to 2022， using the comprehensive water quality index method （WQI）， the Mann-Kendall trend test， and the principal component analysis in the study. The results indicated that， in terms of water quality parameters， dissolved oxygen showed an increasing trend， and ammonia nitrogen， potassium permanganate index， as well as total phosphorus exhibited opposite trends， but these trends were not statistically significant. Spatially， the water quality at all monitoring sites demonstrated a significant improvement， with upstream water quality being better than the downstream. Temporally， the WQI revealed that the urban rivers in Shanghai improved year by year from 2018 to 2022， with the water quality evaluation improving from Class Ⅲ to Class Ⅱ. This reflected significant enhancement in water quality under remediation efforts. Principal component analysis identified that dissolved oxygen and total phosphorus， as the key factors， influencing the urban river water quality in Shanghai from 2018 to 2022. Furthermore， the water quality of urban rivers in Shanghai during dry seasons was better than that during wet seasons， with dissolved oxygen and total phosphorus similarly being the influencing factors during both periods. These findings suggest that changes in dissolved oxygen and total phosphorus should be paid special attention to in urban rivers management.
Urban rivers， as an essential component of the urban ecosystem， play a crucial role in urban development， and understanding the variation of water environment and conducting water quality assessments are improtant for urban planning and environmental protection policies formulation. The spatial and temporal variation in water quality of urban rivers in Yangpu District， Shanghai， China， were analyzed based on the monthly data of 18 monitoring sites from 2018 to 2022， using the comprehensive water quality index method （WQI）， the Mann-Kendall trend test， and the principal component analysis in the study. The results indicated that， in terms of water quality parameters， dissolved oxygen showed an increasing trend， and ammonia nitrogen， potassium permanganate index， as well as total phosphorus exhibited opposite trends， but these trends were not statistically significant. Spatially， the water quality at all monitoring sites demonstrated a significant improvement， with upstream water quality being better than the downstream. Temporally， the WQI revealed that the urban rivers in Shanghai improved year by year from 2018 to 2022， with the water quality evaluation improving from Class Ⅲ to Class Ⅱ. This reflected significant enhancement in water quality under remediation efforts. Principal component analysis identified that dissolved oxygen and total phosphorus， as the key factors， influencing the urban river water quality in Shanghai from 2018 to 2022. Furthermore， the water quality of urban rivers in Shanghai during dry seasons was better than that during wet seasons， with dissolved oxygen and total phosphorus similarly being the influencing factors during both periods. These findings suggest that changes in dissolved oxygen and total phosphorus should be paid special attention to in urban rivers management.
2025, 43(11): 21-29.
doi: 10.13205/j.hjgc.202511003
Abstract:
In the urban development process， some existing sewage treatment plants are encountering the challenge of insufficient treatment capacity. In developed urban zones， constructing new sewage treatment plants is often restricted by high land costs， limited space， and long construction periods. Against this backdrop， in-situ expansion technology has emerged as an effective solution. A sewage treatment plant in Guangzhou， originally designed with a capacity of 1.5×105 m3/d， has been operating over-capacity due to a sharp increase in wastewater volume caused by regional development. To address the issue of insufficient treatment capacity， the plant has designed and implemented an in-situ expansion and technological transformation strategy， successfully increasing its treatment capacity from 1.5×105 m3/d to 2×105 m3/d. Its core lies in the detailed expansion strategies for each treatment process segment. One of the key aspects is the upgrading of the process flow. The original process， which consisted of modified AAO （anaerobic-anoxic-oxic） + secondary sedimentation tank + high-efficiency Sedimentation， has been innovatively improved to "modified AAO + secondary sedimentation tank （integrated aeration and sedimentation） + magnetic coagulation sedimentation. This upgraded process not only enhances the overall treatment efficiency but also significantly improves the plant's ability to handle the increased volume of wastewater. In addition to the process upgrade， the plant has also adopted a phased implementation strategy for technological renovation based on actual influent water quality. This approach allows for a more flexible and cost-effective expansion process. By carefully analyzing the actual water quality data and adjusting the renovation plan accordingly， the plant can achieve an optimal balance between capacity expansion and cost control. This phased implementation strategy maximizes the cost-effectiveness by optimizing investment and minimizing operational costs. Compared with traditional new construction methods， in-situ expansion technology offers several significant advantages. Firstly， it conserves land resources by making full use of the existing plant's infrastructure and facilities， thus avoiding the need for additional land acquisition. Secondly， it reduces engineering investment costs， as the renovation and upgrade of existing facilities are generally less expensive than constructing an entirely new plant. Lastly， it lowers operating costs by leveraging the existing operational systems and personnel， thereby achieving scale economies. In conclusion， the in-situ expansion and technological transformation of the Guangzhou sewage treatment plant not only successfully increases its treatment capacity but also provides an economical and efficient solution. This case demonstrates that in-situ expansion technology can be an excellent alternative for addressing the capacity limitations of existing sewage treatment plants in urban areas， especially where land is scarce and financial resources are constrained.
In the urban development process， some existing sewage treatment plants are encountering the challenge of insufficient treatment capacity. In developed urban zones， constructing new sewage treatment plants is often restricted by high land costs， limited space， and long construction periods. Against this backdrop， in-situ expansion technology has emerged as an effective solution. A sewage treatment plant in Guangzhou， originally designed with a capacity of 1.5×105 m3/d， has been operating over-capacity due to a sharp increase in wastewater volume caused by regional development. To address the issue of insufficient treatment capacity， the plant has designed and implemented an in-situ expansion and technological transformation strategy， successfully increasing its treatment capacity from 1.5×105 m3/d to 2×105 m3/d. Its core lies in the detailed expansion strategies for each treatment process segment. One of the key aspects is the upgrading of the process flow. The original process， which consisted of modified AAO （anaerobic-anoxic-oxic） + secondary sedimentation tank + high-efficiency Sedimentation， has been innovatively improved to "modified AAO + secondary sedimentation tank （integrated aeration and sedimentation） + magnetic coagulation sedimentation. This upgraded process not only enhances the overall treatment efficiency but also significantly improves the plant's ability to handle the increased volume of wastewater. In addition to the process upgrade， the plant has also adopted a phased implementation strategy for technological renovation based on actual influent water quality. This approach allows for a more flexible and cost-effective expansion process. By carefully analyzing the actual water quality data and adjusting the renovation plan accordingly， the plant can achieve an optimal balance between capacity expansion and cost control. This phased implementation strategy maximizes the cost-effectiveness by optimizing investment and minimizing operational costs. Compared with traditional new construction methods， in-situ expansion technology offers several significant advantages. Firstly， it conserves land resources by making full use of the existing plant's infrastructure and facilities， thus avoiding the need for additional land acquisition. Secondly， it reduces engineering investment costs， as the renovation and upgrade of existing facilities are generally less expensive than constructing an entirely new plant. Lastly， it lowers operating costs by leveraging the existing operational systems and personnel， thereby achieving scale economies. In conclusion， the in-situ expansion and technological transformation of the Guangzhou sewage treatment plant not only successfully increases its treatment capacity but also provides an economical and efficient solution. This case demonstrates that in-situ expansion technology can be an excellent alternative for addressing the capacity limitations of existing sewage treatment plants in urban areas， especially where land is scarce and financial resources are constrained.
2025, 43(11): 30-39.
doi: 10.13205/j.hjgc.202511004
Abstract:
To solve the critical issue of antibiotic residues in the effluent of urban wastewater treatment plants， this study investigated the enhancement of constructed wetlands （CWs） through the application of calamus-based biochar fillers to improve the removal efficiency of sulfamethoxazole （SMX） and erythromycin （ERY）. The research focuses on optimizing the operational methods and parameters of CWs， and analyzing the distribution of antibiotic resistance genes （ARGs） and the microbial community structure. The findings were as follows： 1） horizontal subsurface flow constructed wetland demonstrated a markedly higher removal rate for SMX， ERY， and nitrogenous nutrients compared to vertical subsurface flow constructed wetland （P<0.05）， indicating its superior performance in deep water purification； 2）the optimal removal efficiencies for SMX and ERY， reaching 90.5% and 92.7%， respectively， were achieved when the dosage of calamus-based biochar fillers was set at 4% and the hydraulic retention time was maintained at 3 days； 3） the substantial reduction of antibiotic resistance genes in the constructed wetlands effluent was 81.2% when biochar filler dosage increased from 2% to 4%， but the substantial reduction of antibiotic resistance genes in the constructed wetlands effluent was 74.4% when biochar filler dosage increased from 2% to 4%. Meanwhile， the absolute abundance of sul1 decreased from 1.2×109 copies/g in 2% biochar filler to 9.6×108 copies/g in 4% biochar filler， and further to 3.8×108 copies/g in 6% biochar filler， respectively. Additionally， the abundance of antibiotic-resistant bacteria， specifically Rhodococcus and Luteolibacter， within the substrate significantly decreased by 16%. These would reduce the ecological safety risks in water bodies. These findings provide new insights for enhancing constructed wetland systems， enabling the sustainable and efficient removal of antibiotic residues from municipal wastewater treatment plant effluents.
To solve the critical issue of antibiotic residues in the effluent of urban wastewater treatment plants， this study investigated the enhancement of constructed wetlands （CWs） through the application of calamus-based biochar fillers to improve the removal efficiency of sulfamethoxazole （SMX） and erythromycin （ERY）. The research focuses on optimizing the operational methods and parameters of CWs， and analyzing the distribution of antibiotic resistance genes （ARGs） and the microbial community structure. The findings were as follows： 1） horizontal subsurface flow constructed wetland demonstrated a markedly higher removal rate for SMX， ERY， and nitrogenous nutrients compared to vertical subsurface flow constructed wetland （P<0.05）， indicating its superior performance in deep water purification； 2）the optimal removal efficiencies for SMX and ERY， reaching 90.5% and 92.7%， respectively， were achieved when the dosage of calamus-based biochar fillers was set at 4% and the hydraulic retention time was maintained at 3 days； 3） the substantial reduction of antibiotic resistance genes in the constructed wetlands effluent was 81.2% when biochar filler dosage increased from 2% to 4%， but the substantial reduction of antibiotic resistance genes in the constructed wetlands effluent was 74.4% when biochar filler dosage increased from 2% to 4%. Meanwhile， the absolute abundance of sul1 decreased from 1.2×109 copies/g in 2% biochar filler to 9.6×108 copies/g in 4% biochar filler， and further to 3.8×108 copies/g in 6% biochar filler， respectively. Additionally， the abundance of antibiotic-resistant bacteria， specifically Rhodococcus and Luteolibacter， within the substrate significantly decreased by 16%. These would reduce the ecological safety risks in water bodies. These findings provide new insights for enhancing constructed wetland systems， enabling the sustainable and efficient removal of antibiotic residues from municipal wastewater treatment plant effluents.
2025, 43(11): 40-49.
doi: 10.13205/j.hjgc.202511005
Abstract:
The utilization of iron and manganese minerals in water purification has gained significant research attention recently， driven by the need for sustainable and cost-effective solutions to address water pollution. Their remarkable properties， such as potent ion exchange capabilities， excellent adsorption potential， and notable oxidation characteristics， make them highly promising matrix materials for water treatment. These minerals are not only abundant and eco-friendly but also exhibit unique physicochemical properties that enhance their effectiveness in removing contaminants from water systems. To thoroughly examine and compare the efficacy of iron and manganese minerals in removing nitrogen and phosphorus in constructed wetlands， sponge iron and manganese sand were selected as substrates for a series of adsorption experiments. The phase composition and surface morphology of these substrates were analyzed using X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The experiments showed that， under static conditions， both sponge iron and manganese sand exhibited superior adsorption effects on total phosphorus （TP） compared to ammonia nitrogen （NH+4-N）. The theoretical saturated adsorption capacity for TP was 587.38 mg/kg for sponge iron and 284.51 mg/kg for manganese sand， with a desorption rate of only around 10%. This low desorption rate suggests that the adsorbed phosphorus is unlikely to be released back into the water， making these materials highly effective for long-term phosphorus removal. In dynamic vertical flow tests， sponge iron effectively eliminated TP through a combination of adsorption and co-precipitation involving metal mineral components. Both soluble reactive phosphorus （SRP） and particulate phosphorus （PP） showed impressive removal efficiencies， demonstrating the versatility of sponge iron in targeting different forms of phosphorus. However， due to the lack of ion exchange mechanisms， the average removal rate for NH+4-N was only around 40%， indicating its limited effectiveness for nitrogen removal. In contrast， manganese sand， with its unique metal mineral composition， surface morphology， and chemical adsorption-dominated mechanism， exhibited strong adsorption capacity for various pollutants. The presence of manganese oxides facilitated redox reactions， crucial for degrading organic pollutants and removing heavy metals. Additionally， manganese sand was particularly effective in removing macromolecular substances in aromatic proteins， enhancing dissolved organic matter （DOM） components and significantly improving water quality. These findings strongly suggest that manganese sand holds great promise for extensive application in water treatment.
The utilization of iron and manganese minerals in water purification has gained significant research attention recently， driven by the need for sustainable and cost-effective solutions to address water pollution. Their remarkable properties， such as potent ion exchange capabilities， excellent adsorption potential， and notable oxidation characteristics， make them highly promising matrix materials for water treatment. These minerals are not only abundant and eco-friendly but also exhibit unique physicochemical properties that enhance their effectiveness in removing contaminants from water systems. To thoroughly examine and compare the efficacy of iron and manganese minerals in removing nitrogen and phosphorus in constructed wetlands， sponge iron and manganese sand were selected as substrates for a series of adsorption experiments. The phase composition and surface morphology of these substrates were analyzed using X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The experiments showed that， under static conditions， both sponge iron and manganese sand exhibited superior adsorption effects on total phosphorus （TP） compared to ammonia nitrogen （NH+4-N）. The theoretical saturated adsorption capacity for TP was 587.38 mg/kg for sponge iron and 284.51 mg/kg for manganese sand， with a desorption rate of only around 10%. This low desorption rate suggests that the adsorbed phosphorus is unlikely to be released back into the water， making these materials highly effective for long-term phosphorus removal. In dynamic vertical flow tests， sponge iron effectively eliminated TP through a combination of adsorption and co-precipitation involving metal mineral components. Both soluble reactive phosphorus （SRP） and particulate phosphorus （PP） showed impressive removal efficiencies， demonstrating the versatility of sponge iron in targeting different forms of phosphorus. However， due to the lack of ion exchange mechanisms， the average removal rate for NH+4-N was only around 40%， indicating its limited effectiveness for nitrogen removal. In contrast， manganese sand， with its unique metal mineral composition， surface morphology， and chemical adsorption-dominated mechanism， exhibited strong adsorption capacity for various pollutants. The presence of manganese oxides facilitated redox reactions， crucial for degrading organic pollutants and removing heavy metals. Additionally， manganese sand was particularly effective in removing macromolecular substances in aromatic proteins， enhancing dissolved organic matter （DOM） components and significantly improving water quality. These findings strongly suggest that manganese sand holds great promise for extensive application in water treatment.
2025, 43(11): 50-57.
doi: 10.13205/j.hjgc.202511006
Abstract:
Chlorinated hydrocarbons is one of the typical groundwater contaminants. Conventional pump-and-treat technology is apt to cause a tailing phenomenon in its later stage. Surfactant enhanced aquifer remediation （SEAR） is a promising remediation technology； however， its engineering applications have rarely been reported in China. This study implemented enhanced remediation of chlorinated hydrocarbons contaminated groundwater with in-situ microemulsion flushing at pilot scale， the flushing solution （i.e.， microemulsion precursor） composed of 3.0% SDS（sodium dodecyl sulfate）-7.0% n-butanol-2.0% KCl was injected into 5 to 10 meters deep from ground surface with 1 m3/d for 14 consecutive days in a chlorinated hydrocarbons contaminated zone， in a simultaneous extraction-injection mode. The monitoring data of this pilot showed that the concentration of each component of the flushing solution， i.e.， SDS， n-butanol， potassium ion and chloride ion in the extraction well peaked on the 10th to 12th day， with corresponding flushing volume approximately 1 time of the effective pore volume. Solubility of all the chlorinated hydrocarbons was enhanced through in-situ microemulsion flushing， with groundwater concentration 1.06 to 86.90 times that prior to flushing， and solubilization efficiency was in order of tetrachloroethylene （PCE） > trichloroethylene （TCE） > vinyl chloride （VC） > cis-1，2-dichloroethylene （cis-DCE）. The stronger the hydrophobicity of a chlorinated hydrocarbons， the higher its solubilization efficiency. A removal rate of 88.81% to 100% of various chlorinated hydrocarbons in the aquifer medium （soil） was achieved， indicating
Chlorinated hydrocarbons is one of the typical groundwater contaminants. Conventional pump-and-treat technology is apt to cause a tailing phenomenon in its later stage. Surfactant enhanced aquifer remediation （SEAR） is a promising remediation technology； however， its engineering applications have rarely been reported in China. This study implemented enhanced remediation of chlorinated hydrocarbons contaminated groundwater with in-situ microemulsion flushing at pilot scale， the flushing solution （i.e.， microemulsion precursor） composed of 3.0% SDS（sodium dodecyl sulfate）-7.0% n-butanol-2.0% KCl was injected into 5 to 10 meters deep from ground surface with 1 m3/d for 14 consecutive days in a chlorinated hydrocarbons contaminated zone， in a simultaneous extraction-injection mode. The monitoring data of this pilot showed that the concentration of each component of the flushing solution， i.e.， SDS， n-butanol， potassium ion and chloride ion in the extraction well peaked on the 10th to 12th day， with corresponding flushing volume approximately 1 time of the effective pore volume. Solubility of all the chlorinated hydrocarbons was enhanced through in-situ microemulsion flushing， with groundwater concentration 1.06 to 86.90 times that prior to flushing， and solubilization efficiency was in order of tetrachloroethylene （PCE） > trichloroethylene （TCE） > vinyl chloride （VC） > cis-1，2-dichloroethylene （cis-DCE）. The stronger the hydrophobicity of a chlorinated hydrocarbons， the higher its solubilization efficiency. A removal rate of 88.81% to 100% of various chlorinated hydrocarbons in the aquifer medium （soil） was achieved， indicating
2025, 43(11): 58-66.
doi: 10.13205/j.hjgc.202511007
Abstract:
The paper aims to explore the characteristics and patterns of dynamic changes in urban groundwater by organizing and analyzing the monitoring data on water level and water temperature in urban groundwater in Shenyang. Understanding these changes is crucial for protecting the urban groundwater environment and ensuring the safety of the urban water supply. The research methodology includes using groundwater monitoring data from five districts within Shenyang from Nov. 2022 to Oct. 2023， analyzing in detail the characteristics of the dynamic changes of groundwater， and comprehensively evaluating the changing characteristics in groundwater level， groundwater flow field， and groundwater temperature from multiple perspectives， including meteorology， hydrology， and anthropogenic activities. The basic law of the dynamic change of groundwater level and water temperature in Shenyang urban area in one year was obtained. The results showed that the groundwater dynamics in Shenyang were significantly influenced by seasonal precipitation， river level changes， and human activities （e.g.， mining， heat pump system use， etc.）. These findings not only reveal the dynamic change law of groundwater in Shenyang in the monitoring period， but also provide a valuable scientific basis for future water resources management.
The paper aims to explore the characteristics and patterns of dynamic changes in urban groundwater by organizing and analyzing the monitoring data on water level and water temperature in urban groundwater in Shenyang. Understanding these changes is crucial for protecting the urban groundwater environment and ensuring the safety of the urban water supply. The research methodology includes using groundwater monitoring data from five districts within Shenyang from Nov. 2022 to Oct. 2023， analyzing in detail the characteristics of the dynamic changes of groundwater， and comprehensively evaluating the changing characteristics in groundwater level， groundwater flow field， and groundwater temperature from multiple perspectives， including meteorology， hydrology， and anthropogenic activities. The basic law of the dynamic change of groundwater level and water temperature in Shenyang urban area in one year was obtained. The results showed that the groundwater dynamics in Shenyang were significantly influenced by seasonal precipitation， river level changes， and human activities （e.g.， mining， heat pump system use， etc.）. These findings not only reveal the dynamic change law of groundwater in Shenyang in the monitoring period， but also provide a valuable scientific basis for future water resources management.
2025, 43(11): 67-72.
doi: 10.13205/j.hjgc.202511008
Abstract:
Urban stormwater runoff has emerged as a critical environmental challenge， significantly impacting aquatic ecosystems by transporting pollutants such as nitrogen， phosphorus， and organic matter into the receiving water bodies. These contaminants contribute to water quality degradation and disrupt ecological balance， necessitating effective and sustainable mitigation strategies. Aquatic plants have shown considerable promise in addressing this issue due to their natural pollutant removal capabilities. This study investigated the purification efficiencies of four aquatic plant species， Acorus calamus， Lythrum salicaria， Thalia dealbata， and Iristectorum， and evaluated their treatment efficiencies on TP， TN and COD in rainwater by simulating urban rainwater runoff hydroponic experiments. It was found that the combinations of Iris tectorum and Thalia dealbata （IT）， Iris tectorum and Acorus calamus （IA）， Thalia dealbata and Lythrum salicaria （TL）， and Lythrum salicaria and Acorus calamus （LA） showed different effects on the removal of pollutants from rainwater runoff. The results showed that the TN removal rate of each plant combination ranged from 90% to 97%， 87% to 93%， 90% to 93% and 93% to 97%， respectively. The co-cultured Thalia dealbata and Lythrum salicaria group
Urban stormwater runoff has emerged as a critical environmental challenge， significantly impacting aquatic ecosystems by transporting pollutants such as nitrogen， phosphorus， and organic matter into the receiving water bodies. These contaminants contribute to water quality degradation and disrupt ecological balance， necessitating effective and sustainable mitigation strategies. Aquatic plants have shown considerable promise in addressing this issue due to their natural pollutant removal capabilities. This study investigated the purification efficiencies of four aquatic plant species， Acorus calamus， Lythrum salicaria， Thalia dealbata， and Iristectorum， and evaluated their treatment efficiencies on TP， TN and COD in rainwater by simulating urban rainwater runoff hydroponic experiments. It was found that the combinations of Iris tectorum and Thalia dealbata （IT）， Iris tectorum and Acorus calamus （IA）， Thalia dealbata and Lythrum salicaria （TL）， and Lythrum salicaria and Acorus calamus （LA） showed different effects on the removal of pollutants from rainwater runoff. The results showed that the TN removal rate of each plant combination ranged from 90% to 97%， 87% to 93%， 90% to 93% and 93% to 97%， respectively. The co-cultured Thalia dealbata and Lythrum salicaria group
2025, 43(11): 73-83.
doi: 10.13205/j.hjgc.202511009
Abstract:
China’s National 14th Five-Year Plan and the 2035 Vision proposes eliminating heavily polluted weather and continuously improving the environmental quality of Beijing-Tianjin-Hebei with the surrounding area （BTHSA）. The air pollutant concentration and GDAS data in BTHSA in 2021 were adopted to explore heavy pollution's spatial and temporal characteristics. Then， they were used to analyze the distribution of the airflow trajectories and the primary pollutants’ potential source during the typical heavy pollution processes. The results indicated that： in terms of temporal distribution， BTHSA had no heavy pollution days in August and September， while January and March had the largest day number. Besides， the main primary pollutants were PM2.5， PM10， and O3 during heavy pollution days. Regarding spatial distribution， heavy pollution occurred in the entire region of BTHSA in spring and winter， and only in some areas in summer and autumn. The number of heavily polluted and severely polluted days showed significant spatial aggregation. The analysis of typical heavy pollution processes displayed that： in spring， PM10 in Shijiazhuang was influenced by short-range transport from the east and long-range transport airflow trajectories from the northwest. In summer， O3 in Taiyuan was dominated by emissions from external sources and long-distance transport from the northwest. In autumn， PM2.5 in Hebi was due to local source emissions and short-range transport. In winter， PM2.5 in Kaifeng mainly came from short-range transport from the east. Therefore， countermeasures were proposed including tapping the distribution characteristics and potential source areas of primary pollutants in each heavy pollution process， targeting the development of joint prevention and control measures， and coordinating the prevention and control of air pollution in key regions.
China’s National 14th Five-Year Plan and the 2035 Vision proposes eliminating heavily polluted weather and continuously improving the environmental quality of Beijing-Tianjin-Hebei with the surrounding area （BTHSA）. The air pollutant concentration and GDAS data in BTHSA in 2021 were adopted to explore heavy pollution's spatial and temporal characteristics. Then， they were used to analyze the distribution of the airflow trajectories and the primary pollutants’ potential source during the typical heavy pollution processes. The results indicated that： in terms of temporal distribution， BTHSA had no heavy pollution days in August and September， while January and March had the largest day number. Besides， the main primary pollutants were PM2.5， PM10， and O3 during heavy pollution days. Regarding spatial distribution， heavy pollution occurred in the entire region of BTHSA in spring and winter， and only in some areas in summer and autumn. The number of heavily polluted and severely polluted days showed significant spatial aggregation. The analysis of typical heavy pollution processes displayed that： in spring， PM10 in Shijiazhuang was influenced by short-range transport from the east and long-range transport airflow trajectories from the northwest. In summer， O3 in Taiyuan was dominated by emissions from external sources and long-distance transport from the northwest. In autumn， PM2.5 in Hebi was due to local source emissions and short-range transport. In winter， PM2.5 in Kaifeng mainly came from short-range transport from the east. Therefore， countermeasures were proposed including tapping the distribution characteristics and potential source areas of primary pollutants in each heavy pollution process， targeting the development of joint prevention and control measures， and coordinating the prevention and control of air pollution in key regions.
2025, 43(11): 84-92.
doi: 10.13205/j.hjgc.202511010
Abstract:
At present， odor pollution has become a key problem restricting the industrialization of compost. Odor gas biological deodorization technology is widely used by most scholars for its advantages of high efficiency， no secondary pollution， good ecological safety， simple equipment， easy operation， relatively low cost， convenient maintenance and management. To study the enhancement effect of biochar on biofilter and the change of microbial community in its filler， this paper took NH3 in compost tail gas as the target pollutant， and bamboo biochar enhanced biofilter as the research object， and carried out the experiments on NH3 removing effect in biofilters with different additions of biochar （0%， 10%， 20% by volume ratio， respectively）， and with different heights （20， 40 cm）. The changes of NH+4-N， NO-3-N， and microbial communities in the filler were analyzed in depth. The results showed that the average removal efficiency of NH3 in biofilters with different treatments was higher than 92%. The best removal effect， 99.17%， was achieved in the biofilter when the biochar content was 20% and the packing height was 40 cm； NH+4-N was more converted to NO-3-N， NO-2-N or other compounds when the biochar content was 20% and the packing height was 20 cm and 40 cm， among which NO-2-N content reached the highest level on the 24th day， which was respectively 0.37 g/kg， 0.31 g/kg. Biome analysis showed that microbial diversity was highest in the treatment with 20% biochar addition. The microbial diversity index was 4.42 and 4.34 at 20 cm and 40 cm heights， respectively； Brumimicrobium， norank-f-MWH-CFBk5， and norank-f-Fodinicurvataceae were the dominant fungi after the passage of NH3 genera. Therefore， the use of biochar-enhanced biofilter for NH3 treatment has a good application prospect.
At present， odor pollution has become a key problem restricting the industrialization of compost. Odor gas biological deodorization technology is widely used by most scholars for its advantages of high efficiency， no secondary pollution， good ecological safety， simple equipment， easy operation， relatively low cost， convenient maintenance and management. To study the enhancement effect of biochar on biofilter and the change of microbial community in its filler， this paper took NH3 in compost tail gas as the target pollutant， and bamboo biochar enhanced biofilter as the research object， and carried out the experiments on NH3 removing effect in biofilters with different additions of biochar （0%， 10%， 20% by volume ratio， respectively）， and with different heights （20， 40 cm）. The changes of NH+4-N， NO-3-N， and microbial communities in the filler were analyzed in depth. The results showed that the average removal efficiency of NH3 in biofilters with different treatments was higher than 92%. The best removal effect， 99.17%， was achieved in the biofilter when the biochar content was 20% and the packing height was 40 cm； NH+4-N was more converted to NO-3-N， NO-2-N or other compounds when the biochar content was 20% and the packing height was 20 cm and 40 cm， among which NO-2-N content reached the highest level on the 24th day， which was respectively 0.37 g/kg， 0.31 g/kg. Biome analysis showed that microbial diversity was highest in the treatment with 20% biochar addition. The microbial diversity index was 4.42 and 4.34 at 20 cm and 40 cm heights， respectively； Brumimicrobium， norank-f-MWH-CFBk5， and norank-f-Fodinicurvataceae were the dominant fungi after the passage of NH3 genera. Therefore， the use of biochar-enhanced biofilter for NH3 treatment has a good application prospect.
2025, 43(11): 93-104.
doi: 10.13205/j.hjgc.202511011
Abstract:
In the paper， MnPO/TiO2 catalysts was prepared by using MnO x， which has strong electron transport capacity， excellent redox property and environmental friendliness， as the active component， and phosphoric acid was used to modulate the acidity and redox property of Mn/TiO2 catalysts， and their denitrification performance was tested， and the adsorption characteristics of reactant molecules on the surface of the catalysts were simulated by DFT method. The results showed that the highest denitrification activity occurred when the Mn/P was 2， the active component loading was 10%， and the calcination temperature was 350 ℃， and the denitrification efficiency was above 80% at 120 ℃， and above 99% at a temperature range of 150 to 210 ℃. The results of the anti-SO2 test and characterization showed that the Mn2P2O7 could effectively improve the sulfur resistance of the MnPO/TiO2 catalysts. DFT simulation result showed that the adsorption characteristics of NH3 and NO on the surfaces of Mn2P2O7 （111） and Mn3O4 （110）， and the adsorption of NO on the surfaces of Mn2P2O7（111） and Mn3O4（110） with N-terminal adsorption， were relatively stronger. The adsorption energies of SO2 on the surfaces of Mn2P2O7（111） and Mn3O4（110） were much larger than those of NO. SO2 was at a disadvantage for competitive adsorption with NO on the catalyst surface. Meanwhile， the adsorption energy of SO2 on the surface of Mn2P2O7（111） was larger than that on the surface of Mn3O4（110）， which indicated Mn2P2O7 could improve the sulfur resistance of MnPO/TiO2. The adsorption energy of the H2O molecule on the surface of Mn2P2O7（111） was -129.56 kJ/mol， and on the surface of Mn3O4（110） surface was -135.2 kJ/mol and -133.65 kJ/mol for Mn1 and Mn2， respectively， both of which are chemisorbed.
In the paper， MnPO/TiO2 catalysts was prepared by using MnO x， which has strong electron transport capacity， excellent redox property and environmental friendliness， as the active component， and phosphoric acid was used to modulate the acidity and redox property of Mn/TiO2 catalysts， and their denitrification performance was tested， and the adsorption characteristics of reactant molecules on the surface of the catalysts were simulated by DFT method. The results showed that the highest denitrification activity occurred when the Mn/P was 2， the active component loading was 10%， and the calcination temperature was 350 ℃， and the denitrification efficiency was above 80% at 120 ℃， and above 99% at a temperature range of 150 to 210 ℃. The results of the anti-SO2 test and characterization showed that the Mn2P2O7 could effectively improve the sulfur resistance of the MnPO/TiO2 catalysts. DFT simulation result showed that the adsorption characteristics of NH3 and NO on the surfaces of Mn2P2O7 （111） and Mn3O4 （110）， and the adsorption of NO on the surfaces of Mn2P2O7（111） and Mn3O4（110） with N-terminal adsorption， were relatively stronger. The adsorption energies of SO2 on the surfaces of Mn2P2O7（111） and Mn3O4（110） were much larger than those of NO. SO2 was at a disadvantage for competitive adsorption with NO on the catalyst surface. Meanwhile， the adsorption energy of SO2 on the surface of Mn2P2O7（111） was larger than that on the surface of Mn3O4（110）， which indicated Mn2P2O7 could improve the sulfur resistance of MnPO/TiO2. The adsorption energy of the H2O molecule on the surface of Mn2P2O7（111） was -129.56 kJ/mol， and on the surface of Mn3O4（110） surface was -135.2 kJ/mol and -133.65 kJ/mol for Mn1 and Mn2， respectively， both of which are chemisorbed.
2025, 43(11): 105-114.
doi: 10.13205/j.hjgc.202511012
Abstract:
As the key area of Chengdu's industrial planning and industrial layout， Pengzhou is not only the key area of Chengdu's industrial source emissions， one of the main transmission channels of air pollutants， but also the upstream area of pollution sources' cross-border transportation and cold air activities. This study utilized the WRF-CALPUFF air quality model， in conjunction with environmental air quality monitoring data from Pengzhou， meteorological observations， as well as an industrial emission inventory， to simulate and analyze the contributions of key industrial sources to ambient PM2.5 concentrations and their impacts on environmental air quality during the winter of 2022 （from December 2022 to February 2023）. The results indicated that the cement and metal products industries were major contributors to PM2.5 in Pengzhou during winter， with an average contribution of 1.96 μg/m3 to the PM2.5 concentration， accounting for over 70% of total industrial sources. During polluted weather conditions， the impact of these industries on air quality was even more significant， reaching approximately 80% of the total influence. Comparative analysis of two typical pollution episodes from January to February 2023 revealed that the contributions of key industrial sources to PM2.5 concentrations were closely related to local wind field characteristics， particularly under the influence of northerly and north-easterly winds， where pollutants accumulation was more pronounced. In the winter of 2022， the top 20 companies in terms of PM2.5 contributions in Pengzhou had an average contribution of 2.26 μg/m3， which was more pronounced during polluted weather， reaching 3.34 μg/m3 and accounting for about 87% of the total contributions from all key enterprises. Therefore， by simulating the pollution impact of enterprises， this study highlights the importance of managing key industries， providing a scientific basis for environmental protection departments to formulate off-peak production and emergency emission reduction measures for key industries during autumn and winter， and supporting the continuous improvement of air quality.
As the key area of Chengdu's industrial planning and industrial layout， Pengzhou is not only the key area of Chengdu's industrial source emissions， one of the main transmission channels of air pollutants， but also the upstream area of pollution sources' cross-border transportation and cold air activities. This study utilized the WRF-CALPUFF air quality model， in conjunction with environmental air quality monitoring data from Pengzhou， meteorological observations， as well as an industrial emission inventory， to simulate and analyze the contributions of key industrial sources to ambient PM2.5 concentrations and their impacts on environmental air quality during the winter of 2022 （from December 2022 to February 2023）. The results indicated that the cement and metal products industries were major contributors to PM2.5 in Pengzhou during winter， with an average contribution of 1.96 μg/m3 to the PM2.5 concentration， accounting for over 70% of total industrial sources. During polluted weather conditions， the impact of these industries on air quality was even more significant， reaching approximately 80% of the total influence. Comparative analysis of two typical pollution episodes from January to February 2023 revealed that the contributions of key industrial sources to PM2.5 concentrations were closely related to local wind field characteristics， particularly under the influence of northerly and north-easterly winds， where pollutants accumulation was more pronounced. In the winter of 2022， the top 20 companies in terms of PM2.5 contributions in Pengzhou had an average contribution of 2.26 μg/m3， which was more pronounced during polluted weather， reaching 3.34 μg/m3 and accounting for about 87% of the total contributions from all key enterprises. Therefore， by simulating the pollution impact of enterprises， this study highlights the importance of managing key industries， providing a scientific basis for environmental protection departments to formulate off-peak production and emergency emission reduction measures for key industries during autumn and winter， and supporting the continuous improvement of air quality.
2025, 43(11): 115-122.
doi: 10.13205/j.hjgc.202511013
Abstract:
The incorporation technology， the three-tower system of indirect dry cooling tower， FGD， and exhaust flue gas stack in power plants has developed rapidly， especially in Northwest China. It has advantages including energy saving， water saving， and environmental protection. But there is no operating experience of the three-tower system for 1000 MW power plants and cooling towers higher than 200 m. Due to the large volume of the two air cooling towers and their close proximity， there is no relevant practical experiences on their mutual impact and surrounding tall buildings’ impact on their performance. Therefore， numerical simulation methods were proposed. Through numerical simulation， a detailed calculation was conducted on the air cooling system of a 2×1000 MW unit， to analyze the impacts of winds with different directions and speeds in summer， surrounding tall buildings， and cooling tower spacing on the airflow field inside the tower and the thermal performance of the radiator， as well as the safety of the unit. The results indicated that the wind affects the airflow velocity and temperature distribution inside the cooling tower obviously， different wind speeds and directions had different influences on heat transfer， and there will be reverse flow and penetrating flow when the wind speed was higher than 16 m/s； the surrounding tall buildings also had some protective effect for the cooling towers； both will affect the heat transfer and the flue gas exhaust. Under the extreme condition， the back pressure of the boiler raised， the maximum back pressure was 32.2 kPa， which was still lower than the warning limit value of 48 kPa， and within the controllable range， then the boiler can operate safely.
The incorporation technology， the three-tower system of indirect dry cooling tower， FGD， and exhaust flue gas stack in power plants has developed rapidly， especially in Northwest China. It has advantages including energy saving， water saving， and environmental protection. But there is no operating experience of the three-tower system for 1000 MW power plants and cooling towers higher than 200 m. Due to the large volume of the two air cooling towers and their close proximity， there is no relevant practical experiences on their mutual impact and surrounding tall buildings’ impact on their performance. Therefore， numerical simulation methods were proposed. Through numerical simulation， a detailed calculation was conducted on the air cooling system of a 2×1000 MW unit， to analyze the impacts of winds with different directions and speeds in summer， surrounding tall buildings， and cooling tower spacing on the airflow field inside the tower and the thermal performance of the radiator， as well as the safety of the unit. The results indicated that the wind affects the airflow velocity and temperature distribution inside the cooling tower obviously， different wind speeds and directions had different influences on heat transfer， and there will be reverse flow and penetrating flow when the wind speed was higher than 16 m/s； the surrounding tall buildings also had some protective effect for the cooling towers； both will affect the heat transfer and the flue gas exhaust. Under the extreme condition， the back pressure of the boiler raised， the maximum back pressure was 32.2 kPa， which was still lower than the warning limit value of 48 kPa， and within the controllable range， then the boiler can operate safely.
2025, 43(11): 123-132.
doi: 10.13205/j.hjgc.202511014
Abstract:
Lignin-based biochar is renowned for its multifunctionality and environmental benefits. However， there is limited information on the intricate relationship between structural characteristics and the adsorption capacities of lignin-based biochar derived from different biomass sources. This study comparatively analyzed the Pb2+ adsorption performance of lignin-based biochar prepared from NaOH/ethanol-pretreated hardwoods （poplar woodchips） and herbaceous plants （wheat straw） at varying pyrolysis temperatures （350， 550， 750 ℃） and chemical modifications （KOH and chitosan）. Notably， chitosan-modified wheat straw lignin-based biochar demonstrated superior Pb2+ adsorption performance， achieving an adsorption capacity of 37.78 mg/g. Its unique structural properties， including active functional groups ［—OH， —C（O）NH—， etc.］ on the surface， contributed to this excellent adsorption capacity. The adsorption mechanism conformed to the quasi-second-order kinetics， indicating chemisorption was the dominant mechanism， while intraparticle diffusion occurred in two stages. Additionally， isothermal adsorption data were best described by the Freundlich model， suggesting that both chemical complexation and surface heterogeneity govern the adsorption process. These findings offer valuable insights into how the origin of lignin impacts the adsorption efficacy of its derived biochar.
Lignin-based biochar is renowned for its multifunctionality and environmental benefits. However， there is limited information on the intricate relationship between structural characteristics and the adsorption capacities of lignin-based biochar derived from different biomass sources. This study comparatively analyzed the Pb2+ adsorption performance of lignin-based biochar prepared from NaOH/ethanol-pretreated hardwoods （poplar woodchips） and herbaceous plants （wheat straw） at varying pyrolysis temperatures （350， 550， 750 ℃） and chemical modifications （KOH and chitosan）. Notably， chitosan-modified wheat straw lignin-based biochar demonstrated superior Pb2+ adsorption performance， achieving an adsorption capacity of 37.78 mg/g. Its unique structural properties， including active functional groups ［—OH， —C（O）NH—， etc.］ on the surface， contributed to this excellent adsorption capacity. The adsorption mechanism conformed to the quasi-second-order kinetics， indicating chemisorption was the dominant mechanism， while intraparticle diffusion occurred in two stages. Additionally， isothermal adsorption data were best described by the Freundlich model， suggesting that both chemical complexation and surface heterogeneity govern the adsorption process. These findings offer valuable insights into how the origin of lignin impacts the adsorption efficacy of its derived biochar.
2025, 43(11): 133-141.
doi: 10.13205/j.hjgc.202511015
Abstract:
In this study， the pyrolysis kinetic properties and product characteristics of typical organic components in decommissioned wind turbine blades were thoroughly investigated. The three main organic components in the blades： glass fiber reinforced resin （GFRP）， foam material （FM）， and adhesive material （AM） were systematically analyzed by using thermogravimetric analysis-Fourier transform infrared spectroscopy-mass spectrometry （TG-FTIR-MS）. It was found that the pyrolysis process of GFRP was mainly characterized by devolatilization， with its maximum weight loss occurring at about 350 ℃ and a low residual carbon content after pyrolysis. The maximum weight loss in the pyrolysis process of adhesive material occurred at about 375 ℃ and 350 ℃， respectively. The pyrolytic weight loss of the foam material showed two stages with peaks at 265 ℃ and 460 ℃， respectively. Fourier transform infrared spectroscopy （FTIR） analysis showed that the main products generated during pyrolysis included carbon dioxide （CO2）， water （H2O）， and methane （CH4）， and that an increase in temperature increase rate helped to accelerate the decomposition of the samples. Mass spectrometry （MS） analysis further revealed gases containing nitrogen， sulfur， and chlorine， as well as other organic compounds released during the pyrolysis process. During the pyrolysis process， extra attention needs to be paid to the removal of N and Cl from the pyrolysis gas-liquid phase products. This study provides valuable basic data for the thermochemical characterization of wind turbine blades and provides a theoretical basis for their effective recycling. By gaining a deeper understanding of the behaviors and product properties of these organic components during pyrolysis， targeted recycling technologies can be better developed for the sustainable use of wind turbine blades.
In this study， the pyrolysis kinetic properties and product characteristics of typical organic components in decommissioned wind turbine blades were thoroughly investigated. The three main organic components in the blades： glass fiber reinforced resin （GFRP）， foam material （FM）， and adhesive material （AM） were systematically analyzed by using thermogravimetric analysis-Fourier transform infrared spectroscopy-mass spectrometry （TG-FTIR-MS）. It was found that the pyrolysis process of GFRP was mainly characterized by devolatilization， with its maximum weight loss occurring at about 350 ℃ and a low residual carbon content after pyrolysis. The maximum weight loss in the pyrolysis process of adhesive material occurred at about 375 ℃ and 350 ℃， respectively. The pyrolytic weight loss of the foam material showed two stages with peaks at 265 ℃ and 460 ℃， respectively. Fourier transform infrared spectroscopy （FTIR） analysis showed that the main products generated during pyrolysis included carbon dioxide （CO2）， water （H2O）， and methane （CH4）， and that an increase in temperature increase rate helped to accelerate the decomposition of the samples. Mass spectrometry （MS） analysis further revealed gases containing nitrogen， sulfur， and chlorine， as well as other organic compounds released during the pyrolysis process. During the pyrolysis process， extra attention needs to be paid to the removal of N and Cl from the pyrolysis gas-liquid phase products. This study provides valuable basic data for the thermochemical characterization of wind turbine blades and provides a theoretical basis for their effective recycling. By gaining a deeper understanding of the behaviors and product properties of these organic components during pyrolysis， targeted recycling technologies can be better developed for the sustainable use of wind turbine blades.
2025, 43(11): 142-151.
doi: 10.13205/j.hjgc.202511016
Abstract:
Hot metal pre-desulfurization has become an indispensable key process in modern iron and steel enterprises， and desulfurization slag is the main solid waste generated in the desulfurization process， with an annual output of 10 to 20 million tons. Therefore， the treatment and utilization of desulfurization slag generated in the desulfurization process are important issues of concern of steel enterprises. Based on these， this paper first introduces the desulfurization mechanism of different desulfurizers and identifies the possible chemical composition of desulfurization slag by analyzing the reaction process. After that， the chemical and phase compositions of desulfurization slag are comprehensively reviewed， to lay a foundation for the following utilization. Finally， the research progress on reuse and high value-added utilization of desulfurization slag in steel mills is summarized. The result shows that the properly treated desulfurization slag has multiple values， which can not only recover the metal iron， but also replace lime for steelmaking， and the tailings can also realize the utilization of building materials. In addition， desulfurization slag also shows great potential in ion adsorption for heavy metal polluted wastewater and using as rubber filler.
Hot metal pre-desulfurization has become an indispensable key process in modern iron and steel enterprises， and desulfurization slag is the main solid waste generated in the desulfurization process， with an annual output of 10 to 20 million tons. Therefore， the treatment and utilization of desulfurization slag generated in the desulfurization process are important issues of concern of steel enterprises. Based on these， this paper first introduces the desulfurization mechanism of different desulfurizers and identifies the possible chemical composition of desulfurization slag by analyzing the reaction process. After that， the chemical and phase compositions of desulfurization slag are comprehensively reviewed， to lay a foundation for the following utilization. Finally， the research progress on reuse and high value-added utilization of desulfurization slag in steel mills is summarized. The result shows that the properly treated desulfurization slag has multiple values， which can not only recover the metal iron， but also replace lime for steelmaking， and the tailings can also realize the utilization of building materials. In addition， desulfurization slag also shows great potential in ion adsorption for heavy metal polluted wastewater and using as rubber filler.
2025, 43(11): 152-161.
doi: 10.13205/j.hjgc.202511017
Abstract:
The resource utilization of stale refuse in a standard landfill in the Greater Bay Area was analyzed. Samples of stale refuse at different depths， with a landfill age of 9 years， were collected for physicochemical analysis. The results showed that the combustible component accounted for 56% to 72% of the stale refuse， which was similar to the proportion of combustible components in fresh waste （67%）， and the calorific value reached 8167 to 11230 kJ/kg. And the recyclable component accounted for 4.5% to 7.0%， with metal components accounting for less than 2%， and the remaining fine fraction components accounting for 20% to 40%. It was recommended to use a combined process of “crushing + vibration screen+ roller screen + magnetic separation” to improve screening efficiency， optimize combustible composition， and enhance the fuel characteristics. The material under the coarse screen should be disposed of harmlessly before being used as base material for building， due to its serious pollution state. Fine fraction containing petroleum hydrocarbons and heavy metals （chromium， copper， zinc， arsenic） exceeding standards should also be disposed of harmlessly before being used as backfill for sealing and covering soil， instead of being applied directly.
The resource utilization of stale refuse in a standard landfill in the Greater Bay Area was analyzed. Samples of stale refuse at different depths， with a landfill age of 9 years， were collected for physicochemical analysis. The results showed that the combustible component accounted for 56% to 72% of the stale refuse， which was similar to the proportion of combustible components in fresh waste （67%）， and the calorific value reached 8167 to 11230 kJ/kg. And the recyclable component accounted for 4.5% to 7.0%， with metal components accounting for less than 2%， and the remaining fine fraction components accounting for 20% to 40%. It was recommended to use a combined process of “crushing + vibration screen+ roller screen + magnetic separation” to improve screening efficiency， optimize combustible composition， and enhance the fuel characteristics. The material under the coarse screen should be disposed of harmlessly before being used as base material for building， due to its serious pollution state. Fine fraction containing petroleum hydrocarbons and heavy metals （chromium， copper， zinc， arsenic） exceeding standards should also be disposed of harmlessly before being used as backfill for sealing and covering soil， instead of being applied directly.
2025, 43(11): 162-170.
doi: 10.13205/j.hjgc.202511018
Abstract:
Based on the high moisture， sticky nature， and slow hydrolysis rate of three-phase organic solid residue from food waste， this study employed a leach bed reactor （LBR） with an added bulking agent and micro-aeration to perform separate hydrolysis-acidification. The results showed that in 14 days， the hydrolysis and acidification rates reached 515.6 g sCOD/kg VS and 360.4 g sCODSMPs/kg VS， respectively. Acetic acid and butyric acid accounted for approximately 60% to 73% of the soluble metabolic products， while the peak concentrations of ammonia nitrogen and nitrate were 1300.5 mg/L and 98.8 mg/L， respectively， with no detectable nitrite nitrogen accumulation. Microbial community analysis indicated that Firmicutes was dominant， increasing from 21% in the inoculated sludge to 98.3%， with genera such as Sporanaerobacter （26%）， Bacillus （29%）， and Ureibacillus （16%） jointly contributing to hydrolysis-acidification. Methane production tests revealed that the acidification liquid achieved a methane conversion rate of 85.1%， yielding an accumulated methane production of 298 mL CH4/g COD（approximately 32 m3 CH4/t solid residue）， confirming its suitability for direct methanogenesis. This study offers a new strategy for high-rate methane production from three-phase organic solid residue， with potential to enhance the existing anaerobic digestion processes of food waste.
Based on the high moisture， sticky nature， and slow hydrolysis rate of three-phase organic solid residue from food waste， this study employed a leach bed reactor （LBR） with an added bulking agent and micro-aeration to perform separate hydrolysis-acidification. The results showed that in 14 days， the hydrolysis and acidification rates reached 515.6 g sCOD/kg VS and 360.4 g sCODSMPs/kg VS， respectively. Acetic acid and butyric acid accounted for approximately 60% to 73% of the soluble metabolic products， while the peak concentrations of ammonia nitrogen and nitrate were 1300.5 mg/L and 98.8 mg/L， respectively， with no detectable nitrite nitrogen accumulation. Microbial community analysis indicated that Firmicutes was dominant， increasing from 21% in the inoculated sludge to 98.3%， with genera such as Sporanaerobacter （26%）， Bacillus （29%）， and Ureibacillus （16%） jointly contributing to hydrolysis-acidification. Methane production tests revealed that the acidification liquid achieved a methane conversion rate of 85.1%， yielding an accumulated methane production of 298 mL CH4/g COD（approximately 32 m3 CH4/t solid residue）， confirming its suitability for direct methanogenesis. This study offers a new strategy for high-rate methane production from three-phase organic solid residue， with potential to enhance the existing anaerobic digestion processes of food waste.
2025, 43(11): 171-178.
doi: 10.13205/j.hjgc.202511019
Abstract:
The research focused on coal to olefin sludge， and explored the optimal process condition for coal chemical sludge blending and pulping by utilizing thermal hydrolysis technology，to achieve structural depolymerization and directional conversion of bound water. By comparing the changes in key parameters such as sludge viscosity， relaxation time， and capillary water absorption time before and after sludge modification， the optimal modification conditions were determined. In addition， a comprehensive and objective evaluation of the modification effect of sludge was conducted by combining the dynamic changes in chemical oxygen consumption and sludge mixing concentration. The results showed that when the modification temperature was 180 ℃ and the hydrolysis time was 240 minutes， the viscosity of the sludge decreased from 919 mPa · s to 57 mPa · s， and the capillary water absorption time decreased sharply from over 5000 s to 108 s. The flow state and dewatering performance of the sludge were significantly improved； after sludge modification， the chemical oxygen consumption increased from 1460 mg/L to 18203 mg/L， with an increase of 12.5 times； by blending modified sludge with coal for pulping， when the sludge addition was 10%， the maximum slurry concentration obtained was 63.8%， meeting the requirement of industry standard of no less than 63% for coal water slurry pulping； and the modification time was calibrated using a hot reaction kettle， confirming that the optimal modification time for industrial demonstration was 60 minutes. The research provides new ideas for the harmless， resourceful， and rational disposal of coal chemical sludge， and lays a foundation for constructing a "waste-free" green new process with nearly zero emission of typical difficult-to-treat solid waste in the coal chemical industry.
The research focused on coal to olefin sludge， and explored the optimal process condition for coal chemical sludge blending and pulping by utilizing thermal hydrolysis technology，to achieve structural depolymerization and directional conversion of bound water. By comparing the changes in key parameters such as sludge viscosity， relaxation time， and capillary water absorption time before and after sludge modification， the optimal modification conditions were determined. In addition， a comprehensive and objective evaluation of the modification effect of sludge was conducted by combining the dynamic changes in chemical oxygen consumption and sludge mixing concentration. The results showed that when the modification temperature was 180 ℃ and the hydrolysis time was 240 minutes， the viscosity of the sludge decreased from 919 mPa · s to 57 mPa · s， and the capillary water absorption time decreased sharply from over 5000 s to 108 s. The flow state and dewatering performance of the sludge were significantly improved； after sludge modification， the chemical oxygen consumption increased from 1460 mg/L to 18203 mg/L， with an increase of 12.5 times； by blending modified sludge with coal for pulping， when the sludge addition was 10%， the maximum slurry concentration obtained was 63.8%， meeting the requirement of industry standard of no less than 63% for coal water slurry pulping； and the modification time was calibrated using a hot reaction kettle， confirming that the optimal modification time for industrial demonstration was 60 minutes. The research provides new ideas for the harmless， resourceful， and rational disposal of coal chemical sludge， and lays a foundation for constructing a "waste-free" green new process with nearly zero emission of typical difficult-to-treat solid waste in the coal chemical industry.
2025, 43(11): 179-186.
doi: 10.13205/j.hjgc.202511020
Abstract:
The annual output of copper smelting slag in the world exceeds 50 million tons， and stacking is the current mainstream copper smelting slag treatment method， which causes the risk of heavy metal overflow and potential environmental pollution. In this paper， non-ferrous iron was extracted from copper smelting slag by sulfuric acid leaching to prepare ferrous sulfate solution， and then iron oxide yellow pigment was prepared by air oxidation. The influence of key parameters， such as leaching liquid concentration， air flow， temperature， treating time， raw material particle size and crystal seed addition was investigated by the experiments. The results showed that when the leaching temperature was set at 95 ℃， the leaching time was 2 hours， and the liquid-solid ratio was 5∶1， the leaching efficiency of iron in copper smelting slag was as high as 96.5%. When the ratio of crystal to seed was 33%， the oxidation time was 50 h， the air volume was 0.8 m3/h， and the terminal pH value was adjusted to 3.5， the content of Fe2O3 in the prepared iron oxide yellow pigment reached 86.4%. This process has the advantages of wide availability of raw materials and simple experimental operation， and provides a new utilization path for copper smelting slag.
The annual output of copper smelting slag in the world exceeds 50 million tons， and stacking is the current mainstream copper smelting slag treatment method， which causes the risk of heavy metal overflow and potential environmental pollution. In this paper， non-ferrous iron was extracted from copper smelting slag by sulfuric acid leaching to prepare ferrous sulfate solution， and then iron oxide yellow pigment was prepared by air oxidation. The influence of key parameters， such as leaching liquid concentration， air flow， temperature， treating time， raw material particle size and crystal seed addition was investigated by the experiments. The results showed that when the leaching temperature was set at 95 ℃， the leaching time was 2 hours， and the liquid-solid ratio was 5∶1， the leaching efficiency of iron in copper smelting slag was as high as 96.5%. When the ratio of crystal to seed was 33%， the oxidation time was 50 h， the air volume was 0.8 m3/h， and the terminal pH value was adjusted to 3.5， the content of Fe2O3 in the prepared iron oxide yellow pigment reached 86.4%. This process has the advantages of wide availability of raw materials and simple experimental operation， and provides a new utilization path for copper smelting slag.
2025, 43(11): 187-195.
doi: 10.13205/j.hjgc.202511021
Abstract:
Coal gangue is the largest solid waste in China. A large amount of untreated coal gangue will bring about many environmental problems. So it is urgent to deal with coal gangue in bulk and at high value. In this study， high-carbon and high-sulfur coal gangue was used as raw material to decarbonize and desulfurize， and raw coal gangue and two kinds of decarbonized coal gangues were used to prepare ceramsite， namely. By adjusting the raw material ratio， preparation parameters of green pellets， and firing parameters of ceramsite， the preparation process and performance characteristics of high-strength ceramsite were systematically studied. The research showed that the reverse flotation decarbonized coal gangue was more suitable for preparing ceramsite than raw coal gangue and self-heating decarbonized coal gangue. The optimal pelleting parameters were as follows： pelleting time of 8 minutes， green moisture of 14.0%， and the proportion of raw material -0.074 mm particles of 70%. Under this condition， the falling strength， compressive strength， and bursting temperature of green pellets were more than 20 times/0.5 m， 20 N/pellet， 335 ℃， and the compressive strength of dry pellets was 68 N/pellet. The high-strength ceramsites were obtained by roasting at 1125 ℃ for 25 min. The bulk density， apparent density， water absorption， cylinder compressive strength， and cold compressive strength were 884 kg/m3， 1667 kg/m3， 8.24%， 7.49 MPa， and 2541 N/pellet， respectively， meet the requirements of 900 grade high-strength ceramsites. The research provides theoretical support and a practical basis for the resource utilization of high-sulfur and high-carbon coal gangue， which is helpful in promoting the high-value utilization of solid waste.
Coal gangue is the largest solid waste in China. A large amount of untreated coal gangue will bring about many environmental problems. So it is urgent to deal with coal gangue in bulk and at high value. In this study， high-carbon and high-sulfur coal gangue was used as raw material to decarbonize and desulfurize， and raw coal gangue and two kinds of decarbonized coal gangues were used to prepare ceramsite， namely. By adjusting the raw material ratio， preparation parameters of green pellets， and firing parameters of ceramsite， the preparation process and performance characteristics of high-strength ceramsite were systematically studied. The research showed that the reverse flotation decarbonized coal gangue was more suitable for preparing ceramsite than raw coal gangue and self-heating decarbonized coal gangue. The optimal pelleting parameters were as follows： pelleting time of 8 minutes， green moisture of 14.0%， and the proportion of raw material -0.074 mm particles of 70%. Under this condition， the falling strength， compressive strength， and bursting temperature of green pellets were more than 20 times/0.5 m， 20 N/pellet， 335 ℃， and the compressive strength of dry pellets was 68 N/pellet. The high-strength ceramsites were obtained by roasting at 1125 ℃ for 25 min. The bulk density， apparent density， water absorption， cylinder compressive strength， and cold compressive strength were 884 kg/m3， 1667 kg/m3， 8.24%， 7.49 MPa， and 2541 N/pellet， respectively， meet the requirements of 900 grade high-strength ceramsites. The research provides theoretical support and a practical basis for the resource utilization of high-sulfur and high-carbon coal gangue， which is helpful in promoting the high-value utilization of solid waste.
2025, 43(11): 196-204.
doi: 10.13205/j.hjgc.202511022
Abstract:
To recover nutrients from wastewater and use steel slag material effectively， this study synthesized a modified steel slag material loaded with magnesium oxide， and probed the factors of adsorbing ammonia nitrogen and phosphate from water solution by this material. This study also analyzed the characterization of magnesium modified steel slag materials before and after adsorption by SEM-EDS， XRD， and RITR， in addition， explored the adsorption mechanism by kinetic model and adsorption isotherm model. The results showed that when the steel slag dosage was equal to 0.1 g/L， initial pH was equal to 3， adsorption time was 360 minutes， phosphate and ammonia nitrogen concentration were 220 mg/L and 100 mg/L， the magnesium-modified steel slag demonstrated a good performance in the simultaneous removal of ammonia nitrogen and phosphate， with maximum removal rates of 79.60% and 97.39% for ammonia nitrogen and phosphate. The maximum adsorption capacity of modified steel slag material was 74.973 mg/g and 216.362 mg/g for ammonia nitrogen and phosphate. Furthermore， it was found that the pseudo-2nd-order kinetic model and the Langmuir temperature adsorption curve model could describe the dynamic process of adsorption well. It indicated that the adsorption processes were chemisorption and molecular layer adsorption， and the final products were mainly struvite， suggesting that magnesium-modified steel slag is expected to become a promising material for nitrogen and phosphorus recovery
To recover nutrients from wastewater and use steel slag material effectively， this study synthesized a modified steel slag material loaded with magnesium oxide， and probed the factors of adsorbing ammonia nitrogen and phosphate from water solution by this material. This study also analyzed the characterization of magnesium modified steel slag materials before and after adsorption by SEM-EDS， XRD， and RITR， in addition， explored the adsorption mechanism by kinetic model and adsorption isotherm model. The results showed that when the steel slag dosage was equal to 0.1 g/L， initial pH was equal to 3， adsorption time was 360 minutes， phosphate and ammonia nitrogen concentration were 220 mg/L and 100 mg/L， the magnesium-modified steel slag demonstrated a good performance in the simultaneous removal of ammonia nitrogen and phosphate， with maximum removal rates of 79.60% and 97.39% for ammonia nitrogen and phosphate. The maximum adsorption capacity of modified steel slag material was 74.973 mg/g and 216.362 mg/g for ammonia nitrogen and phosphate. Furthermore， it was found that the pseudo-2nd-order kinetic model and the Langmuir temperature adsorption curve model could describe the dynamic process of adsorption well. It indicated that the adsorption processes were chemisorption and molecular layer adsorption， and the final products were mainly struvite， suggesting that magnesium-modified steel slag is expected to become a promising material for nitrogen and phosphorus recovery
2025, 43(11): 205-212.
doi: 10.13205/j.hjgc.202511023
Abstract:
Most rural domestic sewage treatment draws on the experience of urban sewage treatment， and the lack of reasonable treatment modes in engineering design often results in problems such as incomplete sewage collection， low operation efficiency of treatment facilities and substandard effluent quality. How to realize the effective collection of sewage and the first selection of efficient treatment process is the key to the design of rural domestic sewage treatment facilities. In this paper， we collected the rural sewage treatment data of Hubei， Hunan， Anhui and Jiangxi provinces in the middle reaches of the Yangtze River， and selected 22 typical rural sewage treatment facilities in different terrains for field investigation， and analyzed the current situation of rural sewage treatment， the collection of rural household drainage characteristics and the treatment effect of the facilities in the four provinces. The results showed that by 2022， the domestic sewage treatment rate of rural areas in the four provinces of the Yangtze River are 32.99%， 23.75%， 36.61% and 30.00% respectively， which are lower than the national rural domestic sewage treatment rate（31%）. The concentration of pollutants in facilities is generally lower than that of farmer households， and the inflow concentration of sewage treatment facilities in areas with different terrains is not significantly different. The concentration of COD， SS， NH+4-N， TN and TP are 41.66 to 72.17 mg/L， 24.86 to 46.86 mg/L， 8.00 to 10.06 mg/L， 12.27 to 16.29 mg/L and 1.35 to 1.6 mg/L， respectively. The treatment facilities in the plain area mostly use the biological method， and the bio-ecological combination processes are mostly used in the mountainous area， among which the treatment effect of A3O+MBBR， AO+constructed wetland and A2O+MBR process is better， and they can stably reach the first-class B effluent standard of GB 18918—2002. This research endeavors contribute to the advancement and optimization of strategies aimed at tackling the challenge of rural domestic sewage treatment within the middle reach of the Yangtze River.
Most rural domestic sewage treatment draws on the experience of urban sewage treatment， and the lack of reasonable treatment modes in engineering design often results in problems such as incomplete sewage collection， low operation efficiency of treatment facilities and substandard effluent quality. How to realize the effective collection of sewage and the first selection of efficient treatment process is the key to the design of rural domestic sewage treatment facilities. In this paper， we collected the rural sewage treatment data of Hubei， Hunan， Anhui and Jiangxi provinces in the middle reaches of the Yangtze River， and selected 22 typical rural sewage treatment facilities in different terrains for field investigation， and analyzed the current situation of rural sewage treatment， the collection of rural household drainage characteristics and the treatment effect of the facilities in the four provinces. The results showed that by 2022， the domestic sewage treatment rate of rural areas in the four provinces of the Yangtze River are 32.99%， 23.75%， 36.61% and 30.00% respectively， which are lower than the national rural domestic sewage treatment rate（31%）. The concentration of pollutants in facilities is generally lower than that of farmer households， and the inflow concentration of sewage treatment facilities in areas with different terrains is not significantly different. The concentration of COD， SS， NH+4-N， TN and TP are 41.66 to 72.17 mg/L， 24.86 to 46.86 mg/L， 8.00 to 10.06 mg/L， 12.27 to 16.29 mg/L and 1.35 to 1.6 mg/L， respectively. The treatment facilities in the plain area mostly use the biological method， and the bio-ecological combination processes are mostly used in the mountainous area， among which the treatment effect of A3O+MBBR， AO+constructed wetland and A2O+MBR process is better， and they can stably reach the first-class B effluent standard of GB 18918—2002. This research endeavors contribute to the advancement and optimization of strategies aimed at tackling the challenge of rural domestic sewage treatment within the middle reach of the Yangtze River.
2025, 43(11): 213-221.
doi: 10.13205/j.hjgc.202511024
Abstract:
Polyethylene terephthalate （PET） is widely used in bottle flakes， textile fibers， films， etc.， which generates a large amount of discarded PET products. This results in prominent environmental impacts and an urgent need to explore the mechanism of synergistic efficiency in pollution reduction and carbon reduction. This study identified the dynamic material flow pattern of China's PET industry from 2000 to 2025， measured the environmental impact of the business with the life cycle assessment method， and revealed that recycling is the optimal path for the industry to reduce pollution and synergize with carbon reduction. The results show that China's PET consumption in 2025 will increase by 10.87 times compared with 2000， and the industry's greenhouse gas emissions and acidification potential in 2025 will reach 194.7 Mt CO2-eq and 0.16 Mt SO2-eq， which are 11.1 times and 10.1 times higher than that in 2000， respectively； recycling can effectively replace the environmental impacts of the development process of primary resources， and significantly reduce the quantities for landfill and incineration. From 2000 to 2025， recycling method achieves a cumulative reduction of 19.2% of greenhouse gas emissions， and makes cumulative human toxicity， acidification potential and abiotic resource consumption decreased by 21.9%， 19.0% and 18.7%， respectively. It is recommended to realize the technological upgrading of recycling processes， accelerate the construction of green recycling industry chain， and realize the quality improvement of recycled resources by increasing the proportion of chemical recycling.
Polyethylene terephthalate （PET） is widely used in bottle flakes， textile fibers， films， etc.， which generates a large amount of discarded PET products. This results in prominent environmental impacts and an urgent need to explore the mechanism of synergistic efficiency in pollution reduction and carbon reduction. This study identified the dynamic material flow pattern of China's PET industry from 2000 to 2025， measured the environmental impact of the business with the life cycle assessment method， and revealed that recycling is the optimal path for the industry to reduce pollution and synergize with carbon reduction. The results show that China's PET consumption in 2025 will increase by 10.87 times compared with 2000， and the industry's greenhouse gas emissions and acidification potential in 2025 will reach 194.7 Mt CO2-eq and 0.16 Mt SO2-eq， which are 11.1 times and 10.1 times higher than that in 2000， respectively； recycling can effectively replace the environmental impacts of the development process of primary resources， and significantly reduce the quantities for landfill and incineration. From 2000 to 2025， recycling method achieves a cumulative reduction of 19.2% of greenhouse gas emissions， and makes cumulative human toxicity， acidification potential and abiotic resource consumption decreased by 21.9%， 19.0% and 18.7%， respectively. It is recommended to realize the technological upgrading of recycling processes， accelerate the construction of green recycling industry chain， and realize the quality improvement of recycled resources by increasing the proportion of chemical recycling.
2025, 43(11): 222-230.
doi: 10.13205/j.hjgc.202511025
Abstract:
Based on carbon emission accounting and land use intensity measurement， the temporal and spatial distribution characteristics of carbon emissions level and land use intensity in Suzhou from 2005 to 2020 were analyzed， and the decoupling relationship of land use carbon emission in Suzhou was deeply studied with the decoupling model. The results showed that： 1） The carbon emissions in Suzhou showed an overall upward trend from 2005 to 2020， and the net carbon emissions increased by 2.183×107 t in 15 years. Spatial heterogeneity was obvious. 2） From 2005 to 2020， the intensity of land use in Suzhou showed a trend of increasing first and then decreasing， forming a distribution pattern with Gusu District as the center and a higher degree of land use in the north than in the south. 3） The spatial clustering of carbon decoupling in Suzhou had been significantly enhanced， and it had undergone a transformation from negative correlation to positive correlation. The decoupling mode was mainly strong decoupling and expanding negative decoupling. The intensity of land use showed significant differences in carbon emissions at different stages. Therefore， the government can implement the differentiated carbon emissions control strategy according to local conditions， actively adjust the industrial structure and optimize the allocation of land resources in combination with the local development vision， improve land use efficiency， and promote the coordinated development of ecological environment and economy.
Based on carbon emission accounting and land use intensity measurement， the temporal and spatial distribution characteristics of carbon emissions level and land use intensity in Suzhou from 2005 to 2020 were analyzed， and the decoupling relationship of land use carbon emission in Suzhou was deeply studied with the decoupling model. The results showed that： 1） The carbon emissions in Suzhou showed an overall upward trend from 2005 to 2020， and the net carbon emissions increased by 2.183×107 t in 15 years. Spatial heterogeneity was obvious. 2） From 2005 to 2020， the intensity of land use in Suzhou showed a trend of increasing first and then decreasing， forming a distribution pattern with Gusu District as the center and a higher degree of land use in the north than in the south. 3） The spatial clustering of carbon decoupling in Suzhou had been significantly enhanced， and it had undergone a transformation from negative correlation to positive correlation. The decoupling mode was mainly strong decoupling and expanding negative decoupling. The intensity of land use showed significant differences in carbon emissions at different stages. Therefore， the government can implement the differentiated carbon emissions control strategy according to local conditions， actively adjust the industrial structure and optimize the allocation of land resources in combination with the local development vision， improve land use efficiency， and promote the coordinated development of ecological environment and economy.
2025, 43(11): 231-237.
doi: 10.13205/j.hjgc.202511026
Abstract:
With the rapid economic development and increasing urbanization level of China， the scale of wastewater treatment has reached the top in the world. Sludge， as a by-product of wastewater treatment， has always been a research hotspot in the field of wastewater treatment regarding its safe disposal and resource utilization. Pyrolysis and carbonization technology for sludge， a novel technique that emerged in Japan and Europe in the 1990s， was gradually introduced and applied in China after 2008. Amidst the growing focus on carbon emissions， the resource utilization advantages of sludge pyrolysis and carbonization technology have gathered increasing attention. This paper provides a comparative analysis of global typical sludge pyrolysis and carbonization projects. In Japan， the emphasis of sludge pyrolysis and carbonization is not on the pyrolysis gas， but on the utilization of the resulting sludge char. The primary goal is to promote the application of sludge char in various fields， including fuel， soil improvement， and construction materials. In Europe， the driving force behind sludge pyrolysis and carbonization technology is searching for cleaner alternatives to incineration and the effective recovery of phosphorus from sludge. In China， there is still significant improvement room in the development of key technologies and integrated equipment for sludge pyrolysis and carbonization. Issues such as uneven heat transfer and low efficiency during the process operation need further exploration and optimization. By systematically introducing the engineering design concepts of a specific sludge pyrolysis and carbonization project and conducting a comprehensive carbon emission analysis， this study aims to advance the optimization of key technologies and the promotion of sludge pyrolysis and carbonization projects in China. It also seeks to enhance the operational level of engineering projects and improve the resource utilization efficiency of sludge char products. Overall， this research highlights the potential of sludge pyrolysis and carbonization technology as a sustainable solution for sludge management， aligning with the global trend towards carbon neutrality and resource conservation.
With the rapid economic development and increasing urbanization level of China， the scale of wastewater treatment has reached the top in the world. Sludge， as a by-product of wastewater treatment， has always been a research hotspot in the field of wastewater treatment regarding its safe disposal and resource utilization. Pyrolysis and carbonization technology for sludge， a novel technique that emerged in Japan and Europe in the 1990s， was gradually introduced and applied in China after 2008. Amidst the growing focus on carbon emissions， the resource utilization advantages of sludge pyrolysis and carbonization technology have gathered increasing attention. This paper provides a comparative analysis of global typical sludge pyrolysis and carbonization projects. In Japan， the emphasis of sludge pyrolysis and carbonization is not on the pyrolysis gas， but on the utilization of the resulting sludge char. The primary goal is to promote the application of sludge char in various fields， including fuel， soil improvement， and construction materials. In Europe， the driving force behind sludge pyrolysis and carbonization technology is searching for cleaner alternatives to incineration and the effective recovery of phosphorus from sludge. In China， there is still significant improvement room in the development of key technologies and integrated equipment for sludge pyrolysis and carbonization. Issues such as uneven heat transfer and low efficiency during the process operation need further exploration and optimization. By systematically introducing the engineering design concepts of a specific sludge pyrolysis and carbonization project and conducting a comprehensive carbon emission analysis， this study aims to advance the optimization of key technologies and the promotion of sludge pyrolysis and carbonization projects in China. It also seeks to enhance the operational level of engineering projects and improve the resource utilization efficiency of sludge char products. Overall， this research highlights the potential of sludge pyrolysis and carbonization technology as a sustainable solution for sludge management， aligning with the global trend towards carbon neutrality and resource conservation.
