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2024 Vol. 42, No. 2
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2024, 42(2): 1-9.
doi: 10.13205/j.hjgc.202402001
Abstract:
The treatment and disposal of municipal sewage sludge started late in China, and yet multiple utilization ways and industrialization promotion are still being explored, of which economy is an important factor related to the success of the technical application path and realization of the technical system. “Anaerobic digestion+land use” is one of the mainstream treatment and disposal technical routes of municipal sewage sludge in China. Focusing on “traditional anaerobic digestion+land use” and “advanced anaerobic digestion+land use”, based on the unified accounting method of the whole process operation cost, economic efficiency, and change rules under different sludge characteristics or technical conditions were analyzed. Besides, this study discussed the interaction between economy and technology implementation and put forward optimization suggestions for the application and promotion of the “anaerobic digestion+land use” technical route through economic analysis. This study can provide a basis for the top-level design and technical route selection of municipal sewage sludge treatment and disposal, provide a reference for project operators to evaluate and improve the operation level, and provide support for the promotion and realization of municipal sewage sludge harmless treatment and resource utilization.
The treatment and disposal of municipal sewage sludge started late in China, and yet multiple utilization ways and industrialization promotion are still being explored, of which economy is an important factor related to the success of the technical application path and realization of the technical system. “Anaerobic digestion+land use” is one of the mainstream treatment and disposal technical routes of municipal sewage sludge in China. Focusing on “traditional anaerobic digestion+land use” and “advanced anaerobic digestion+land use”, based on the unified accounting method of the whole process operation cost, economic efficiency, and change rules under different sludge characteristics or technical conditions were analyzed. Besides, this study discussed the interaction between economy and technology implementation and put forward optimization suggestions for the application and promotion of the “anaerobic digestion+land use” technical route through economic analysis. This study can provide a basis for the top-level design and technical route selection of municipal sewage sludge treatment and disposal, provide a reference for project operators to evaluate and improve the operation level, and provide support for the promotion and realization of municipal sewage sludge harmless treatment and resource utilization.
2024, 42(2): 10-22.
doi: 10.13205/j.hjgc.202402002
Abstract:
Due to the low organic content of municipal residual sludge, collaborative treatment and disposal of kitchen waste has attracted wide attention. Using municipal sludge and kitchen waste as raw materials and sawdust as the conditioner, this paper investigated the process performance of co-composting and discussed the transformation characteristics of carbon and nitrogen elements under the disposal approach based on land use. The results indicated that under the conditions of(73±2)% moisture content and(23±1)℃ temperature, earthworms could survive better and improve the stability of vermicompost. Specifically, after a 60-day composting cycle, the average degradation rate of TOC in the earthworm group was about 32.62%, while that in the control group was about 27.13%. The increase rate of TN in the earthworm group was 18.90% to 29.80%, while that in the control group was 15.83% to 27.40%, and the C/N decreased obviously before and after composting. The degradation percentage of the earthworm group was higher. The growth and reproduction characteristics of earthworms in the compost environment were better with a ratio of residual sludge:kitchen waste:sawdust=4:3:3(by dry weight). Therefore, municipal sludge, kitchen waste, and sawdust combined with vermicomposting treatment can effectively accelerate the composting process, and improve the stability of organic matter and the degree of resource utilization, which is conducive to the subsequent land use.
Due to the low organic content of municipal residual sludge, collaborative treatment and disposal of kitchen waste has attracted wide attention. Using municipal sludge and kitchen waste as raw materials and sawdust as the conditioner, this paper investigated the process performance of co-composting and discussed the transformation characteristics of carbon and nitrogen elements under the disposal approach based on land use. The results indicated that under the conditions of(73±2)% moisture content and(23±1)℃ temperature, earthworms could survive better and improve the stability of vermicompost. Specifically, after a 60-day composting cycle, the average degradation rate of TOC in the earthworm group was about 32.62%, while that in the control group was about 27.13%. The increase rate of TN in the earthworm group was 18.90% to 29.80%, while that in the control group was 15.83% to 27.40%, and the C/N decreased obviously before and after composting. The degradation percentage of the earthworm group was higher. The growth and reproduction characteristics of earthworms in the compost environment were better with a ratio of residual sludge:kitchen waste:sawdust=4:3:3(by dry weight). Therefore, municipal sludge, kitchen waste, and sawdust combined with vermicomposting treatment can effectively accelerate the composting process, and improve the stability of organic matter and the degree of resource utilization, which is conducive to the subsequent land use.
2024, 42(2): 23-31.
doi: 10.13205/j.hjgc.202402003
Abstract:
This study aimed at the problem of insufficient carbon sources during the treatment of sulfate wastewater and explored the feasibility of using the alkaline-thermal hydrolysate of residual sludge as the carbon source of sulfate-reducing bacteria(SRBs). Batch experimental results showed that the optimum sludge pretreatment conditions were T=70 ℃, initial pH=13 and t=10 h, and the optimal parameters for SO42- removal by SRBs were ρ(COD)=10000 mg/L, ρ(SO42-)=2500 mg/L, initial pH=7, and T=35 ℃. Under this condition, the removal efficiency of SO42- reached 90% above, and the utilization efficiency of ρ(COD) reached 80%. The SO42- removal efficiency with sludge alkaline-thermal hydrolase was compared with four other SRBs common carbon sources(sodium lactate, sodium propionate, sodium acetate, and glucose), and the experiment showed that the removal efficiency of SO42- using sludge hydrolysate as SRBs carbon source was higher than other carbon sources. The research confirmed that the residual sludge alkaline-thermal hydrolysate can be used as the carbon source of SRBs, which provided favorable support for the treatment of SO42- wastewater and utilization of residual sludge.
This study aimed at the problem of insufficient carbon sources during the treatment of sulfate wastewater and explored the feasibility of using the alkaline-thermal hydrolysate of residual sludge as the carbon source of sulfate-reducing bacteria(SRBs). Batch experimental results showed that the optimum sludge pretreatment conditions were T=70 ℃, initial pH=13 and t=10 h, and the optimal parameters for SO42- removal by SRBs were ρ(COD)=10000 mg/L, ρ(SO42-)=2500 mg/L, initial pH=7, and T=35 ℃. Under this condition, the removal efficiency of SO42- reached 90% above, and the utilization efficiency of ρ(COD) reached 80%. The SO42- removal efficiency with sludge alkaline-thermal hydrolase was compared with four other SRBs common carbon sources(sodium lactate, sodium propionate, sodium acetate, and glucose), and the experiment showed that the removal efficiency of SO42- using sludge hydrolysate as SRBs carbon source was higher than other carbon sources. The research confirmed that the residual sludge alkaline-thermal hydrolysate can be used as the carbon source of SRBs, which provided favorable support for the treatment of SO42- wastewater and utilization of residual sludge.
2024, 42(2): 32-39.
doi: 10.13205/j.hjgc.202402004
Abstract:
To clarify the immobilization effect of sludge biochar on Cu, Pb, and Cd in dredged sediment contaminated by river channel in a mining region, this study used the municipal sludge as raw material to prepare sludge biochar under anoxic condition at 500 ℃, analyzed the influences of addition ratios of different sludge biochar on the distribution and immobilization effect of three heavy metals in dredged sediment, combining with characterization methods of scanning electron microscopy, FTIR and XPS. The results showed that the addition of sludge biochar could improve the stabilization forms of heavy metals in dredged sediment. When the addition ratio was 1.0%, the proportion of Cu, Pb, and Cd in the stable(oxidizable and residual) in dredged sediment increased by 37.7%, 42.9%, and 42.4%, respectively. Sludge biochar mainly immobilizes heavy metals through complexation reaction and precipitation. The leaching concentration of Cu, Pb, and Cd in the dredged sediment after sludge biochar immobilized decreased from 0.876 mg/L, 0.057 mg/L and 0.018 mg/L to 0.253 mg/L, 0.011 mg/L and 0.001 mg/L, respectively. Meanwhile, the leaching concentration was lower than the limit of the Class Ⅲ standard of Environmental Quality Standard for Surface Water(GB 3838—2002). The immobilized dredged sediment can be reused as resources with no risk of secondary dissolution of heavy metals.
To clarify the immobilization effect of sludge biochar on Cu, Pb, and Cd in dredged sediment contaminated by river channel in a mining region, this study used the municipal sludge as raw material to prepare sludge biochar under anoxic condition at 500 ℃, analyzed the influences of addition ratios of different sludge biochar on the distribution and immobilization effect of three heavy metals in dredged sediment, combining with characterization methods of scanning electron microscopy, FTIR and XPS. The results showed that the addition of sludge biochar could improve the stabilization forms of heavy metals in dredged sediment. When the addition ratio was 1.0%, the proportion of Cu, Pb, and Cd in the stable(oxidizable and residual) in dredged sediment increased by 37.7%, 42.9%, and 42.4%, respectively. Sludge biochar mainly immobilizes heavy metals through complexation reaction and precipitation. The leaching concentration of Cu, Pb, and Cd in the dredged sediment after sludge biochar immobilized decreased from 0.876 mg/L, 0.057 mg/L and 0.018 mg/L to 0.253 mg/L, 0.011 mg/L and 0.001 mg/L, respectively. Meanwhile, the leaching concentration was lower than the limit of the Class Ⅲ standard of Environmental Quality Standard for Surface Water(GB 3838—2002). The immobilized dredged sediment can be reused as resources with no risk of secondary dissolution of heavy metals.
2024, 42(2): 40-47.
doi: 10.13205/j.hjgc.202402005
Abstract:
The preparation of activated carbon from sludge is a resourceful way to utilize sludge and with a wide range of applications. However, few studies have been conducted to evaluate the process of sludge-based activated carbon(SDAC) preparation. In this study, the activated carbon prepared from sewage plant sludge was used as an object, and a flow chart of the preparation process was established to quantitatively reveal the environmental impacts and key influencing factors of the preparation process by applying life cycle assessment(LCA). The results showed that the environmental impact of the roasting step dominated the whole preparation process, followed by the grinding or impregnation step, and then the washing and drying steps. The energy consumption of water vapor physical activation, CO2 physical activation, KOH impregnation, ZnCl2 impregnation, H3PO4 impregnation, ZnCl2 molten salt method, and physicochemical method were 68.976, 79.776, 47.376, 53.964, 48.564, 45.828, and 46.764 MJ/kg of activated carbon, respectively, whereas the values of global warming potential were 14.93, 17.06, 15.54, 13.42, 14.51, 12.65 and 13.91 kg CO2 eq/kg of activated carbon, respectively. The LCA results showed that the preparation of activated carbon using the CO2 physical activation method had the highest environmental impact, while the ZnCl2 molten salt method had the lowest environmental impact. The results of sensitivity analysis on the ZnCl2 molten salt method showed that electricity consumption and activator are the two key factors for further optimization of the activated carbon preparation method. Based on the life cycle perspective, the ZnCl2 molten salt method is more effective in preparing SDAC, and the energy-saving modification of the equipment should be strengthened, which can significantly reduce the environmental impact of the SDAC preparation process.
The preparation of activated carbon from sludge is a resourceful way to utilize sludge and with a wide range of applications. However, few studies have been conducted to evaluate the process of sludge-based activated carbon(SDAC) preparation. In this study, the activated carbon prepared from sewage plant sludge was used as an object, and a flow chart of the preparation process was established to quantitatively reveal the environmental impacts and key influencing factors of the preparation process by applying life cycle assessment(LCA). The results showed that the environmental impact of the roasting step dominated the whole preparation process, followed by the grinding or impregnation step, and then the washing and drying steps. The energy consumption of water vapor physical activation, CO2 physical activation, KOH impregnation, ZnCl2 impregnation, H3PO4 impregnation, ZnCl2 molten salt method, and physicochemical method were 68.976, 79.776, 47.376, 53.964, 48.564, 45.828, and 46.764 MJ/kg of activated carbon, respectively, whereas the values of global warming potential were 14.93, 17.06, 15.54, 13.42, 14.51, 12.65 and 13.91 kg CO2 eq/kg of activated carbon, respectively. The LCA results showed that the preparation of activated carbon using the CO2 physical activation method had the highest environmental impact, while the ZnCl2 molten salt method had the lowest environmental impact. The results of sensitivity analysis on the ZnCl2 molten salt method showed that electricity consumption and activator are the two key factors for further optimization of the activated carbon preparation method. Based on the life cycle perspective, the ZnCl2 molten salt method is more effective in preparing SDAC, and the energy-saving modification of the equipment should be strengthened, which can significantly reduce the environmental impact of the SDAC preparation process.
2024, 42(2): 48-56.
doi: 10.13205/j.hjgc.202402006
Abstract:
The residual microplastics(MPs) in excess sludge potentially harm the environment and ecosystems. Therefore, it is necessary to study the migration, fate, and degradation mechanism of MPs in excess sludge, and develop effective degradation methods to deal with the MPs problem. The occurrence state of MPs in excess sludge is first introduced and the effects of MPs on the properties of excess sludge and sludge treatment are analyzed. The effects are closely related to the type, concentration, and particle size of MPs. Secondly, the degradation pathways of MPs in wastewater treatment plants are reviewed, which can be divided into non-biodegradable and biodegradable pathways. Non-biodegradable pathways include pyrolysis and hydrothermal treatment. Biodegradable pathways include sludge composting, anaerobic digestion, and biofilm method. The degradation efficiency and mechanism of MPs are discussed and the characteristics and application prospects of each pathway are analyzed. Among them, hydrothermal treatment and sludge composting have high MPs degradation efficiency, good economic viability, and wide applicability. Currently, the research on the degradation of MPs in excess sludge is still in the preliminary stage, and further research is needed to tackle the MPs problem.
The residual microplastics(MPs) in excess sludge potentially harm the environment and ecosystems. Therefore, it is necessary to study the migration, fate, and degradation mechanism of MPs in excess sludge, and develop effective degradation methods to deal with the MPs problem. The occurrence state of MPs in excess sludge is first introduced and the effects of MPs on the properties of excess sludge and sludge treatment are analyzed. The effects are closely related to the type, concentration, and particle size of MPs. Secondly, the degradation pathways of MPs in wastewater treatment plants are reviewed, which can be divided into non-biodegradable and biodegradable pathways. Non-biodegradable pathways include pyrolysis and hydrothermal treatment. Biodegradable pathways include sludge composting, anaerobic digestion, and biofilm method. The degradation efficiency and mechanism of MPs are discussed and the characteristics and application prospects of each pathway are analyzed. Among them, hydrothermal treatment and sludge composting have high MPs degradation efficiency, good economic viability, and wide applicability. Currently, the research on the degradation of MPs in excess sludge is still in the preliminary stage, and further research is needed to tackle the MPs problem.
2024, 42(2): 57-65.
doi: 10.13205/j.hjgc.202402007
Abstract:
To solve the problem of excessive phosphorus in water, Zn/Fe-LDHs modified red mud(ZFRM) was prepared by coprecipitating Zn/Fe-LDHs onto the surface of red mud(RM) under alkaline conditions, and used to remove phosphate from wastewater. The phosphate removal performance and mechanism of Zn/Fe-LDHs modified red mud were studied by kinetic experiments, thermodynamic experiments, and regeneration experiments, combined with SEM, BET, XRD, and FTIR characterization. The results showed that the adsorption process of ZFRM to phosphorus conformed to the quasi-second-order kinetic model and Langmuir adsorption isotherm model. At 45 ℃, the maximum adsorption capacity was 56.26 mg/g, and the adsorption reaction was spontaneous and entropy-increasing endothermic reaction. The phosphorus removal capacity of ZFRM was less affected by pH. Carbonate ions coexisting in water can inhibit phosphorus adsorption. In the regeneration experiment, the adsorption capacity of ZFRM after 4 regenerations was 19.07 mg/g, and still had good adsorption performance. In addition, lamellar zinc iron hydrotalcite had been successfully coated on the surface of the flocculent red mud, forming a developed pore structure, and significantly increasing the specific surface area. The adsorption mechanism mainly included ion exchange, coordination reaction, and electrostatic action. Compared with other phosphorus removal materials, the synthesized ZFRM had high phosphorus removal efficiency, strong reproducibility, cheap raw materials, and simple synthesis process. It was a highly effective phosphorus removal agent with great potential in application.
To solve the problem of excessive phosphorus in water, Zn/Fe-LDHs modified red mud(ZFRM) was prepared by coprecipitating Zn/Fe-LDHs onto the surface of red mud(RM) under alkaline conditions, and used to remove phosphate from wastewater. The phosphate removal performance and mechanism of Zn/Fe-LDHs modified red mud were studied by kinetic experiments, thermodynamic experiments, and regeneration experiments, combined with SEM, BET, XRD, and FTIR characterization. The results showed that the adsorption process of ZFRM to phosphorus conformed to the quasi-second-order kinetic model and Langmuir adsorption isotherm model. At 45 ℃, the maximum adsorption capacity was 56.26 mg/g, and the adsorption reaction was spontaneous and entropy-increasing endothermic reaction. The phosphorus removal capacity of ZFRM was less affected by pH. Carbonate ions coexisting in water can inhibit phosphorus adsorption. In the regeneration experiment, the adsorption capacity of ZFRM after 4 regenerations was 19.07 mg/g, and still had good adsorption performance. In addition, lamellar zinc iron hydrotalcite had been successfully coated on the surface of the flocculent red mud, forming a developed pore structure, and significantly increasing the specific surface area. The adsorption mechanism mainly included ion exchange, coordination reaction, and electrostatic action. Compared with other phosphorus removal materials, the synthesized ZFRM had high phosphorus removal efficiency, strong reproducibility, cheap raw materials, and simple synthesis process. It was a highly effective phosphorus removal agent with great potential in application.
2024, 42(2): 66-72.
doi: 10.13205/j.hjgc.202402008
Abstract:
In recent years, the safe and low-carbon treatment and disposal of municipal organic solid waste, such as municipal sludge and kitchen waste, has garnered significant attention. This study establishes an accounting methodology for carbon emissions and compensation by using a medium-sized city with a population of 1 million as a case study. Theoretical carbon emission levels for collaborative treatment, traditional incineration, and landfill pathways are analyzed to determine efficient emission reduction strategies through quantifying the contributions of direct and indirect carbon emissions. The results demonstrate that collaborative treatment of municipal organic solid waste yields significantly lower carbon emissions(513 t CO2/year) compared to traditional landfills(12973 t CO2/year) or traditional incineration(14733 t CO2/year). Direct carbon emissions in the collaborative disposal process account for 63%, emphasizing the importance of maximizing resource utilization through biogas production and fermentation products for effective carbon reduction. Indirect carbon emissions during incineration and landfill processes primarily stem from power consumption during incineration(68%) and deep dehydration agent usage during landfill disposal(87%), highlighting these areas as crucial focal points for reducing the overall carbon footprint. This study's findings provide valuable insights into low-carbon approaches towards treating municipal organic solid waste while aiding cities in achieving their goals of attaining carbon neutrality.
In recent years, the safe and low-carbon treatment and disposal of municipal organic solid waste, such as municipal sludge and kitchen waste, has garnered significant attention. This study establishes an accounting methodology for carbon emissions and compensation by using a medium-sized city with a population of 1 million as a case study. Theoretical carbon emission levels for collaborative treatment, traditional incineration, and landfill pathways are analyzed to determine efficient emission reduction strategies through quantifying the contributions of direct and indirect carbon emissions. The results demonstrate that collaborative treatment of municipal organic solid waste yields significantly lower carbon emissions(513 t CO2/year) compared to traditional landfills(12973 t CO2/year) or traditional incineration(14733 t CO2/year). Direct carbon emissions in the collaborative disposal process account for 63%, emphasizing the importance of maximizing resource utilization through biogas production and fermentation products for effective carbon reduction. Indirect carbon emissions during incineration and landfill processes primarily stem from power consumption during incineration(68%) and deep dehydration agent usage during landfill disposal(87%), highlighting these areas as crucial focal points for reducing the overall carbon footprint. This study's findings provide valuable insights into low-carbon approaches towards treating municipal organic solid waste while aiding cities in achieving their goals of attaining carbon neutrality.
2024, 42(2): 73-81.
doi: 10.13205/j.hjgc.202402009
Abstract:
Aiming at the complexity of oily sludge radiation pyrolysis, the temperature field and heat transfer characteristics inside the pyrolysis furnace are unknown. The temperature distribution inside the pyrolysis furnace and the heating characteristics of the materials under different factors were investigated by Fluent software, using double Eulerian model, DO radiation model and multi-component model. The results indicate that the temperature distribution of the sludge in the furnace was divided into two stages of heating and constant temperature with the cut-off point of L/D=10, and 600 ℃ was the optimal pyrolysis final temperature. Meanwhile, higher water content prolongs the sludge pyrolysis time, while lowering the screw speed reduces the amount of final sludge remaining. In addition, setting a heat shield above the radiation tube can significantly improve the uniformity of the entire furnace temperature distribution. Finally, the total recovered energy of the pyrolysis products was 6592.25 kJ through the energy balance analysis of the whole pyrolysis system, with a maximum energy recovery rate of 82%. Among them, the pyrolysis gas energy accounts for 65.78%~90.11% of the total energy input of the system, which can greatly reduce the external energy supply required by the system.
Aiming at the complexity of oily sludge radiation pyrolysis, the temperature field and heat transfer characteristics inside the pyrolysis furnace are unknown. The temperature distribution inside the pyrolysis furnace and the heating characteristics of the materials under different factors were investigated by Fluent software, using double Eulerian model, DO radiation model and multi-component model. The results indicate that the temperature distribution of the sludge in the furnace was divided into two stages of heating and constant temperature with the cut-off point of L/D=10, and 600 ℃ was the optimal pyrolysis final temperature. Meanwhile, higher water content prolongs the sludge pyrolysis time, while lowering the screw speed reduces the amount of final sludge remaining. In addition, setting a heat shield above the radiation tube can significantly improve the uniformity of the entire furnace temperature distribution. Finally, the total recovered energy of the pyrolysis products was 6592.25 kJ through the energy balance analysis of the whole pyrolysis system, with a maximum energy recovery rate of 82%. Among them, the pyrolysis gas energy accounts for 65.78%~90.11% of the total energy input of the system, which can greatly reduce the external energy supply required by the system.
2024, 42(2): 82-96.
doi: 10.13205/j.hjgc.202402010
Abstract:
Biochar-supported Bi2O3-Bi7.90Mo0.10O12.15/Cu4S7(CSB-BOC) composites were prepared by impregnation-post pyrolysis method and its lattice structure, morphology, surface elements, and chemical morphology were characterized and analyzed by XRD, SEM, XPS and other technologies. Subsequently, the performance and mechanism of CSB-BOC activated peroxymonosulfate(PMS) to remove emerging contaminants were explored. Tetracycline hydrochloride(TC), a typical emerging contaminant, was used as the target pollutant, and the effects of different catalyst reaction systems, PMS concentration, anions, humic acid(HA) and pH on pollutant's removal were studied; the stability of CSB-BOC recycling and the feasibility of removing pollutants in slow-gathering areas of river water were investigated; the phytotoxicity of TC degradation intermediates was evaluated. The results showed that CSB-BOC-5-1 had the best catalytic performance. When the concentration of CSB-BOC-5-1 was 0.2 g/L, the concentration of PMS was 0.2 g/L, the concentration of TC was 20 mg/L, pH=6.8, and the temperature was 23 ℃, the removal rate of TC reached 95% within 60 min at room temperature, 2.79 times that of coconut shell carbon(CSB)+PMS. The degradation efficiency after four degradation cycles only decreased by 10 percentage points. The results of the radical quenching experiment and electron spin resonance(ESR) showed that1O2 was the main active species for TC degradation. The degradation products of TC were identified by LC-MS, and two possible degradation pathways were proposed. The phytotoxicity test and the actual water tests showed that the treatment solution of CSB-BOC+PMS for TC degradation was non-toxic or low toxic, and it showed good effect when being used to remove emerging contaminants in the water samples of slow-gathering areas of a river.
Biochar-supported Bi2O3-Bi7.90Mo0.10O12.15/Cu4S7(CSB-BOC) composites were prepared by impregnation-post pyrolysis method and its lattice structure, morphology, surface elements, and chemical morphology were characterized and analyzed by XRD, SEM, XPS and other technologies. Subsequently, the performance and mechanism of CSB-BOC activated peroxymonosulfate(PMS) to remove emerging contaminants were explored. Tetracycline hydrochloride(TC), a typical emerging contaminant, was used as the target pollutant, and the effects of different catalyst reaction systems, PMS concentration, anions, humic acid(HA) and pH on pollutant's removal were studied; the stability of CSB-BOC recycling and the feasibility of removing pollutants in slow-gathering areas of river water were investigated; the phytotoxicity of TC degradation intermediates was evaluated. The results showed that CSB-BOC-5-1 had the best catalytic performance. When the concentration of CSB-BOC-5-1 was 0.2 g/L, the concentration of PMS was 0.2 g/L, the concentration of TC was 20 mg/L, pH=6.8, and the temperature was 23 ℃, the removal rate of TC reached 95% within 60 min at room temperature, 2.79 times that of coconut shell carbon(CSB)+PMS. The degradation efficiency after four degradation cycles only decreased by 10 percentage points. The results of the radical quenching experiment and electron spin resonance(ESR) showed that1O2 was the main active species for TC degradation. The degradation products of TC were identified by LC-MS, and two possible degradation pathways were proposed. The phytotoxicity test and the actual water tests showed that the treatment solution of CSB-BOC+PMS for TC degradation was non-toxic or low toxic, and it showed good effect when being used to remove emerging contaminants in the water samples of slow-gathering areas of a river.
2024, 42(2): 97-103.
doi: 10.13205/j.hjgc.202402011
Abstract:
To clarify the mechanism of the sudden increase of negative pressure near the water inlet pipe and reduce the negative pressure in the dropshaft, the water-air two-phase and air pressure distribution in the dropshaft model were simulated based on the computational fluid dynamics software Fluent. Then, the relationship between the water tongue and the air pressure change near the water inlet pipe was analyzed. Finally, an optimized dropshaft model was proposed and its effect was evaluated. The results showed that when the dimensionless water flow rate was greater than 0.08, the negative pressure near the water inlet pipe began to increase suddenly, and there was basically no change under a small flow rate. The water tongue was the main reason for the sudden increase of negative pressure, which occupied the space of air circulation and increased the loss of airflow. The air supply under the water tongue was insufficient, so the negative pressure would suddenly increase. The study also showed that the optimized dropshaft model formed a water-free cavity area in the space enclosed by the circular diaphragm and the shaft wall opposite the water intake pipe, which expanded the space for airflow, basically ensuring that the airflow near the water inlet pipe was not affected by the water flow, and also reduced the negative pressure and air pressure gradient in the dropshaft.
To clarify the mechanism of the sudden increase of negative pressure near the water inlet pipe and reduce the negative pressure in the dropshaft, the water-air two-phase and air pressure distribution in the dropshaft model were simulated based on the computational fluid dynamics software Fluent. Then, the relationship between the water tongue and the air pressure change near the water inlet pipe was analyzed. Finally, an optimized dropshaft model was proposed and its effect was evaluated. The results showed that when the dimensionless water flow rate was greater than 0.08, the negative pressure near the water inlet pipe began to increase suddenly, and there was basically no change under a small flow rate. The water tongue was the main reason for the sudden increase of negative pressure, which occupied the space of air circulation and increased the loss of airflow. The air supply under the water tongue was insufficient, so the negative pressure would suddenly increase. The study also showed that the optimized dropshaft model formed a water-free cavity area in the space enclosed by the circular diaphragm and the shaft wall opposite the water intake pipe, which expanded the space for airflow, basically ensuring that the airflow near the water inlet pipe was not affected by the water flow, and also reduced the negative pressure and air pressure gradient in the dropshaft.
2024, 42(2): 104-112.
doi: 10.13205/j.hjgc.202402012
Abstract:
In this paper, a granular activated carbon(GAC) enhanced anaerobic dynamic membrane bioreactor(AnDMBR) was constructed. To explore the physicochemical and biological effects of GAC addition on the AnDMBR, the impact of different GAC dosages(3, 6, 10, 20 g/L) on the filtration performance, pollutants removal, methane production and the characteristics of anaerobic sludge and dynamic membrane was investigated. The results showed that, compared to the control reactor without GAC addition, the turbidity removal increased by 3.1 to 12.3 percentage points, and the COD removal increased by 5.7 to 12.1 percentage points. The higher the GAC dosage, the greater the contribution to pollutant removal. Compared to the control reactor without GAC addition, the total methane yield increased by 23.7%, 34.6%, 24.2%, and 8.3%, respectively, with the optimal GAC dosage of 6 g/L for enhanced methane production. Adding GAC can improve the pollutant removal performance and the methanogenesis of the AnDMBR. The supplementation of GAC can reduce the content of extracellular polymeric substances(EPS) in the anaerobic sludge and dynamic membrane as well as the content of all fluorescent dissolved organic matter in the effluent, leading to a decreased growth rate of transmembrane pressure(TMP). GAC could adsorb and enrich biomass to form biological activated carbon, which increased the particle size of anaerobic sludge, modified sludge characteristics, and enhanced the porous structure of the cake layer. These features played a positive role in the long-term stable operation of the AnDMBR.
In this paper, a granular activated carbon(GAC) enhanced anaerobic dynamic membrane bioreactor(AnDMBR) was constructed. To explore the physicochemical and biological effects of GAC addition on the AnDMBR, the impact of different GAC dosages(3, 6, 10, 20 g/L) on the filtration performance, pollutants removal, methane production and the characteristics of anaerobic sludge and dynamic membrane was investigated. The results showed that, compared to the control reactor without GAC addition, the turbidity removal increased by 3.1 to 12.3 percentage points, and the COD removal increased by 5.7 to 12.1 percentage points. The higher the GAC dosage, the greater the contribution to pollutant removal. Compared to the control reactor without GAC addition, the total methane yield increased by 23.7%, 34.6%, 24.2%, and 8.3%, respectively, with the optimal GAC dosage of 6 g/L for enhanced methane production. Adding GAC can improve the pollutant removal performance and the methanogenesis of the AnDMBR. The supplementation of GAC can reduce the content of extracellular polymeric substances(EPS) in the anaerobic sludge and dynamic membrane as well as the content of all fluorescent dissolved organic matter in the effluent, leading to a decreased growth rate of transmembrane pressure(TMP). GAC could adsorb and enrich biomass to form biological activated carbon, which increased the particle size of anaerobic sludge, modified sludge characteristics, and enhanced the porous structure of the cake layer. These features played a positive role in the long-term stable operation of the AnDMBR.
2024, 42(2): 113-120.
doi: 10.13205/j.hjgc.202402013
Abstract:
Pollutants in groundwater are complicated from many sources, and nitrate pollutants are one of them. In this study, a methanotroph-based biofilm reactor was established to find a remediation method with low consumption, high efficiency, and no secondary pollutants, by assaying nitrate reduction efficiency, functional microorganisms, and metabolic pathway.Results showed that the maximum nitrate removal rate reached 98.83% when nitrate nitrogen concentration in the influent was 10 mg/L. DOM component changes found that the dissolved organic matter primarily was a tryptophan-like protein. Macrogenomic analysis revealed that the dominant aerobic methanotrophs in this biofilm reactor were Methylocystis(5.25%) and Methylomonas(2.73%); the dominant anaerobic methanotrophs were Methylmirabilis(0.0016%), and Methanoperedens(0.0016%); and the dominant nitrate-reducing bacteria were mainly Lysobacter(9.72%), Opitutus(2.74%), and Hypomicrobium(2.01%). The KEGG database was annotated to identify microbial functions in the system, including 40 methane-metabolism-related functional genes and 19 nitrogen-metabolism-related functional genes, as well as 5 relatively complete methane metabolism pathways and 6 nitrogen metabolism pathways. Thus, methanogens could be proved with the capability of partial denitrification and good selectivity for nitrate. Relevant research results can provide technical support and a theoretical basis for the remediation of nitrate-contaminated groundwater.
Pollutants in groundwater are complicated from many sources, and nitrate pollutants are one of them. In this study, a methanotroph-based biofilm reactor was established to find a remediation method with low consumption, high efficiency, and no secondary pollutants, by assaying nitrate reduction efficiency, functional microorganisms, and metabolic pathway.Results showed that the maximum nitrate removal rate reached 98.83% when nitrate nitrogen concentration in the influent was 10 mg/L. DOM component changes found that the dissolved organic matter primarily was a tryptophan-like protein. Macrogenomic analysis revealed that the dominant aerobic methanotrophs in this biofilm reactor were Methylocystis(5.25%) and Methylomonas(2.73%); the dominant anaerobic methanotrophs were Methylmirabilis(0.0016%), and Methanoperedens(0.0016%); and the dominant nitrate-reducing bacteria were mainly Lysobacter(9.72%), Opitutus(2.74%), and Hypomicrobium(2.01%). The KEGG database was annotated to identify microbial functions in the system, including 40 methane-metabolism-related functional genes and 19 nitrogen-metabolism-related functional genes, as well as 5 relatively complete methane metabolism pathways and 6 nitrogen metabolism pathways. Thus, methanogens could be proved with the capability of partial denitrification and good selectivity for nitrate. Relevant research results can provide technical support and a theoretical basis for the remediation of nitrate-contaminated groundwater.
2024, 42(2): 121-127.
doi: 10.13205/j.hjgc.202402014
Abstract:
Based on the analysis of the physicochemical properties of graphene oxide(GO), the effects of electrolyte, natural organic matter(NOM), and stable solution concentration on its aggregation and sedimentation in water were studied. The results showed that the concentration of GO stable solution had little effect on its physicochemical properties and stability in water. Electrolytes induced the GO aggregation by reducing Zeta potential in water. The aggregation process presented two stages: reaction limited and diffusion limited. The critical condensation concentrations(CCC) of each electrolyte were 180 mmol/L of Na+, 4.5 mmol/L of Mg2+ and 1.8 mmol/L of Ca2+, respectively. Compared with Mg2+, Ca2+ could strengthen the aggregation process by adsorption bridging. The sedimentation process of GO was also divided into two stages: rapid sedimentation and slow sedimentation, and aggregation was the main factor affecting GO sedimentation. The presence of natural organic matter could effectively inhibit coagulation and enhance the stability of GO in water. However, HA has a complex correlation with GO and Ca2+, which further accelerates the aggregation process. With the increase of GO concentration in water, the aggregation and sedimentation rate were accelerated. In the presence of a lower concentration, GO had higher stability in the water environment.
Based on the analysis of the physicochemical properties of graphene oxide(GO), the effects of electrolyte, natural organic matter(NOM), and stable solution concentration on its aggregation and sedimentation in water were studied. The results showed that the concentration of GO stable solution had little effect on its physicochemical properties and stability in water. Electrolytes induced the GO aggregation by reducing Zeta potential in water. The aggregation process presented two stages: reaction limited and diffusion limited. The critical condensation concentrations(CCC) of each electrolyte were 180 mmol/L of Na+, 4.5 mmol/L of Mg2+ and 1.8 mmol/L of Ca2+, respectively. Compared with Mg2+, Ca2+ could strengthen the aggregation process by adsorption bridging. The sedimentation process of GO was also divided into two stages: rapid sedimentation and slow sedimentation, and aggregation was the main factor affecting GO sedimentation. The presence of natural organic matter could effectively inhibit coagulation and enhance the stability of GO in water. However, HA has a complex correlation with GO and Ca2+, which further accelerates the aggregation process. With the increase of GO concentration in water, the aggregation and sedimentation rate were accelerated. In the presence of a lower concentration, GO had higher stability in the water environment.
2024, 42(2): 128-134.
doi: 10.13205/j.hjgc.202402015
Abstract:
The issue of water pollution and environmental deterioration caused by insufficient processing capacity sewage treatment in rural areas is a critical problem that requires immediate attention. The current rate of urbanization has led to severe neglect of the construction of sewage treatment facilities in rural areas, causing the direct injection of untreated sewage into rivers. Source control, pollution interception, collection, and treatment are essential methods for controlling the pollution of Inferior V-class water bodies. In this paper, we conducted an in-depth analysis on the csuse of the inferior V-class water bodies in typical rural river water, expanded and upgraded rural sewage treatment facilities, and introduced the concept of entropy, to analyze the impact of organic matter, nitrogen, and phosphorus reduction on water environment and emission reduction effect. After upgrading rural sewage treatment facilities from 800 m3/d to 1800 m3/d, the water environment of typical river channels was effectively improved, and the annual entropy increase was reduced by 9.80×107 kJ/K. The stability of the river water environment and water ecosystem depends on maintaining a relative balance between entropy increase and reverse entropy increase. Evaluating the increase in entropy has practical significance for upgrading and renovating sewage plants and controlling the effect of overflow pollution. In the current context of carbon emissions, carbon neutrality, and the treatment of Inferior V-class water bodies, the sustainable treatment of sewage under the concept of entropy will be excepted to be a development focus of new technology evaluation.
The issue of water pollution and environmental deterioration caused by insufficient processing capacity sewage treatment in rural areas is a critical problem that requires immediate attention. The current rate of urbanization has led to severe neglect of the construction of sewage treatment facilities in rural areas, causing the direct injection of untreated sewage into rivers. Source control, pollution interception, collection, and treatment are essential methods for controlling the pollution of Inferior V-class water bodies. In this paper, we conducted an in-depth analysis on the csuse of the inferior V-class water bodies in typical rural river water, expanded and upgraded rural sewage treatment facilities, and introduced the concept of entropy, to analyze the impact of organic matter, nitrogen, and phosphorus reduction on water environment and emission reduction effect. After upgrading rural sewage treatment facilities from 800 m3/d to 1800 m3/d, the water environment of typical river channels was effectively improved, and the annual entropy increase was reduced by 9.80×107 kJ/K. The stability of the river water environment and water ecosystem depends on maintaining a relative balance between entropy increase and reverse entropy increase. Evaluating the increase in entropy has practical significance for upgrading and renovating sewage plants and controlling the effect of overflow pollution. In the current context of carbon emissions, carbon neutrality, and the treatment of Inferior V-class water bodies, the sustainable treatment of sewage under the concept of entropy will be excepted to be a development focus of new technology evaluation.
2024, 42(2): 135-143.
doi: 10.13205/j.hjgc.202402016
Abstract:
Acidic orange 7(AO7) is a typical anionic azo dye, and has attracted widespread attention for its potential hazards to the environment and human health. In this study, molybdenum disulfide(MoS2) was used as an activator of peroxyacetic acid(PAA) for the degradation of AO7. The results indicated that the degradation efficiency of AO7 in the MoS2/PAA system was much higher than that in the MoS2/H2O2 system and MoS2/PI system. The degradation efficiency of AO7 reached 84.2% under the condition of ρ(MoS2)0=0.4 g/L, c(PAA)0=0.4 mmol/L, and initial pH=3.0. In addition, the MoS2/H2O2 system can efficiently degrade various pollutants such as MO, ACE, DCF, SMX, and TC. EPR and quenching experiments result indicated that ·OH, R-O·, and 1O2 generated by the MoS2/PAA system were the main reactive oxygen species for AO7 degradation. UV full wavelength scanning revealed that the azo bonds and aromatic fragments(naphthalene and benzene rings) of AO7 were rapidly disrupted under the attack of active free radicals. Further investigation was conducted on the effects of initial pH, MoS2 dosage, PAA concentration, coexisting water matrix on AO7 degradation. In the co-existing water matrix experiment, Cl-, SO42- and HCO-3 did not affect the removal of AO7, while humic acid(HA) inhibited it. In natural water bodies, the MoS2/PAA system still exhibits strong oxidation performance(up to 60%) towards AO7. Overall, this study provides new knowledge on the degradation of organic pollutants within the MoS2/PAA system.
Acidic orange 7(AO7) is a typical anionic azo dye, and has attracted widespread attention for its potential hazards to the environment and human health. In this study, molybdenum disulfide(MoS2) was used as an activator of peroxyacetic acid(PAA) for the degradation of AO7. The results indicated that the degradation efficiency of AO7 in the MoS2/PAA system was much higher than that in the MoS2/H2O2 system and MoS2/PI system. The degradation efficiency of AO7 reached 84.2% under the condition of ρ(MoS2)0=0.4 g/L, c(PAA)0=0.4 mmol/L, and initial pH=3.0. In addition, the MoS2/H2O2 system can efficiently degrade various pollutants such as MO, ACE, DCF, SMX, and TC. EPR and quenching experiments result indicated that ·OH, R-O·, and 1O2 generated by the MoS2/PAA system were the main reactive oxygen species for AO7 degradation. UV full wavelength scanning revealed that the azo bonds and aromatic fragments(naphthalene and benzene rings) of AO7 were rapidly disrupted under the attack of active free radicals. Further investigation was conducted on the effects of initial pH, MoS2 dosage, PAA concentration, coexisting water matrix on AO7 degradation. In the co-existing water matrix experiment, Cl-, SO42- and HCO-3 did not affect the removal of AO7, while humic acid(HA) inhibited it. In natural water bodies, the MoS2/PAA system still exhibits strong oxidation performance(up to 60%) towards AO7. Overall, this study provides new knowledge on the degradation of organic pollutants within the MoS2/PAA system.
2024, 42(2): 144-151.
doi: 10.13205/j.hjgc.202402017
Abstract:
After the ultra-low emission renovation, the conventional air pollutant emissions from the power and steel industries have been significantly reduced. The new problem caused by unconventional pollutants and colored plumes has gradually attracted people's attention for its visual appearance and "de-whitening" problem for a long time. Based on relevant domestic and international standards and methods, the emission levels of SO3, NH3, filterable particulate matter(FPM), and condensable particulate matter(CPM) at the main exhaust ports in three coal-fired power plants and the sintering machine heads of two iron and steel plants were tested to evaluate the effectiveness of ultra-low emission implementation and the feasibility of colored smoke plume control. The results showed that the emission concentrations of SO3, NH3 and FPM from three coal-fired power plants and sintering flue gas of the two steel plants were 0.11 mg/Nm3 to 1.61 mg/Nm3, 0.02 mg/Nm3 to 1.66 mg/Nm3, and 0.81 mg/Nm3 to 5.76 mg/Nm3, respectively, which were all at a low level, and the emission concentrations of FPM could all meet the ultra-low emission requirements. After implementing the flue gas "de-whitening" transformation, the emission concentrations of SO3 and NH3 from coal-fired power plants or iron and steel plants' sintering processes decreased significantly, but the emission reduction effect was limited. The CPM emission concentrations from three coal-fired power plants and two steel plants' sintering processes were 3.39 mg/Nm3 to 4.82 mg/Nm3 and 26.6 mg/Nm3 to 29.1 mg/Nm3, respectively. The latter was at a higher level, about 3 times the ultra-low emission limit of particulate matter, and about 32 times of FPM emission concentration, and the CPM/total particulate matter(TPM) reached about 97%. Whether in coal-fired power plants or steel plants, applying "de-whitening" technology might not necessarily significantly reduce CPM emissions. Therefore, the feasibility of adding "whitening" transformation after ultra-low emission transformation is worth pondering. In addition, the online monitoring results of particulate matter in coal-fired power plants and iron and steel plants were both at a relatively low level, and far lower than the TPM emission concentrations measured by manual monitoring. The existing online monitoring data, which does not include CPM, has certain limitations and uncertainties in evaluating the particulate matter emissions in flue gas meeting the standard. Hence, it is urgent to improve the existing measurement system and emission standard system of particulate matter in stationary pollution sources to control the emissions of CPM.
After the ultra-low emission renovation, the conventional air pollutant emissions from the power and steel industries have been significantly reduced. The new problem caused by unconventional pollutants and colored plumes has gradually attracted people's attention for its visual appearance and "de-whitening" problem for a long time. Based on relevant domestic and international standards and methods, the emission levels of SO3, NH3, filterable particulate matter(FPM), and condensable particulate matter(CPM) at the main exhaust ports in three coal-fired power plants and the sintering machine heads of two iron and steel plants were tested to evaluate the effectiveness of ultra-low emission implementation and the feasibility of colored smoke plume control. The results showed that the emission concentrations of SO3, NH3 and FPM from three coal-fired power plants and sintering flue gas of the two steel plants were 0.11 mg/Nm3 to 1.61 mg/Nm3, 0.02 mg/Nm3 to 1.66 mg/Nm3, and 0.81 mg/Nm3 to 5.76 mg/Nm3, respectively, which were all at a low level, and the emission concentrations of FPM could all meet the ultra-low emission requirements. After implementing the flue gas "de-whitening" transformation, the emission concentrations of SO3 and NH3 from coal-fired power plants or iron and steel plants' sintering processes decreased significantly, but the emission reduction effect was limited. The CPM emission concentrations from three coal-fired power plants and two steel plants' sintering processes were 3.39 mg/Nm3 to 4.82 mg/Nm3 and 26.6 mg/Nm3 to 29.1 mg/Nm3, respectively. The latter was at a higher level, about 3 times the ultra-low emission limit of particulate matter, and about 32 times of FPM emission concentration, and the CPM/total particulate matter(TPM) reached about 97%. Whether in coal-fired power plants or steel plants, applying "de-whitening" technology might not necessarily significantly reduce CPM emissions. Therefore, the feasibility of adding "whitening" transformation after ultra-low emission transformation is worth pondering. In addition, the online monitoring results of particulate matter in coal-fired power plants and iron and steel plants were both at a relatively low level, and far lower than the TPM emission concentrations measured by manual monitoring. The existing online monitoring data, which does not include CPM, has certain limitations and uncertainties in evaluating the particulate matter emissions in flue gas meeting the standard. Hence, it is urgent to improve the existing measurement system and emission standard system of particulate matter in stationary pollution sources to control the emissions of CPM.
2024, 42(2): 152-160.
doi: 10.13205/j.hjgc.202402018
Abstract:
In this study, the concentrations of major air pollutants in Luohu District of Shenzhen in 2019 were statistically analyzed, the trend of conventional air pollutant concentration in Luohu District was explored, and the correlation between atmospheric pollutant concentration and meteorological factors in Luohu District was analyzed. The potential source analysis of two pollution events in Luohu District in 2019 was analyzed, the principal component analysis of the main pollutant ozone in Luohu District was carried out, and finally, air pollution control suggestions and countermeasures were put forward for Luohu District. The results showed that the concentration of air pollutants in Luohu District in 2019 was greatly affected by the season, and there was a weekend effect, among the 348 effective data of the year. The number of days with the main pollutant as ozone was 225, accounting for 64.66% of the whole year, and the main pollutant in Luohu District in 2019 was ozone. The correlation between particulate matter concentration and other pollutants in Luohu District was significant, and the concentration of pollutants in the atmospheric environment was significantly correlated with temperature, wind, and relative humidity. The results of the analysis of the potential sources of the two air pollution events showed that the northeast direction including Dongguan etc., was the potential input source of O3 and PM2.5 in Luohu District. Four principal components were analyzed through the analysis of the principal component of ozone concentration, of which the first component could explain 59.2% of the ozone concentration, and the main factors affecting atmospheric ozone concentration in Luohu District were wind, humidity, PM2.5, PM10 and SO2. This study provides a reference for the control and treatment of air pollution in Luohu District.
In this study, the concentrations of major air pollutants in Luohu District of Shenzhen in 2019 were statistically analyzed, the trend of conventional air pollutant concentration in Luohu District was explored, and the correlation between atmospheric pollutant concentration and meteorological factors in Luohu District was analyzed. The potential source analysis of two pollution events in Luohu District in 2019 was analyzed, the principal component analysis of the main pollutant ozone in Luohu District was carried out, and finally, air pollution control suggestions and countermeasures were put forward for Luohu District. The results showed that the concentration of air pollutants in Luohu District in 2019 was greatly affected by the season, and there was a weekend effect, among the 348 effective data of the year. The number of days with the main pollutant as ozone was 225, accounting for 64.66% of the whole year, and the main pollutant in Luohu District in 2019 was ozone. The correlation between particulate matter concentration and other pollutants in Luohu District was significant, and the concentration of pollutants in the atmospheric environment was significantly correlated with temperature, wind, and relative humidity. The results of the analysis of the potential sources of the two air pollution events showed that the northeast direction including Dongguan etc., was the potential input source of O3 and PM2.5 in Luohu District. Four principal components were analyzed through the analysis of the principal component of ozone concentration, of which the first component could explain 59.2% of the ozone concentration, and the main factors affecting atmospheric ozone concentration in Luohu District were wind, humidity, PM2.5, PM10 and SO2. This study provides a reference for the control and treatment of air pollution in Luohu District.
2024, 42(2): 161-166.
doi: 10.13205/j.hjgc.202402019
Abstract:
The study selected a typical coking enterprise to carry out the characterization of unit VOCs emissions for four production units with high active volatile organic compounds(VOCs) components, namely, phenol refining, Gumarone, asphalt coke, and tar naphthalene. Unit VOCs exhaust was collected using a Suma tank, and 106 VOCs components were characterized and quantified by gas chromatography-mass spectrometry(GC-MS), and the contribution of each unit's VOCs emission to the generation of O3 in the atmosphere was calculated using the maximum incremental reactivity(MIR). The results showed that: 1) aromatic hydrocarbons, halogenated hydrocarbons, and oxygenated VOCs(OVOCs) were the main featured components of the four units, and the sum of mass fractions accounted for 92.33% to 95.38%. 2) The sum of mass fractions of the top 10 VOCs species ranked by the four units ranged from 90.45 to 93.46%. Among them, benzene, acetone, methylene chloride, ethanol, and toluene were the characteristic species of VOCs emission from coking enterprises. 3) The ozone generation potential(OFP) values of the four units were 278.73 μg/m3 to 426.95 μg/m3, in an order of tar naphthalene unit(426.95 μg/m3)>phenol refining unit(410.43 μg/m3)>asphalt coke unit(294.36 μg/m3)>Gumarone unit(278.73 μg/m3). 4) The contribution of the top 10 species of the four units to OFP ranged from 96.24% to 97.97%. Benzene, toluene, m/p-xylene, ethylene, and acetone were the key active species in the industry. 5) Different coking production units had different species characterizing VOCs emissions, and the active species contributing to OFP varied. The largest active species contributing to OFP from phenol refining unit was m/p-xylene, the largest active species contributing to OFP from Gumarone and asphalt coke unit was ethylene, and the primary active species from tar naphthalene unit was toluene. It is recommended that targeted VOCs emission reduction strategies be formulated based on key active components screened in the study. To control the contribution of VOCs emissions to the OFP in the coking industry, priority should be given to the adoption of targeted measures to control the emissions of characteristic pollutant components in different installation areas, such as focusing on strengthening the collection and treatment of respiratory gases from the storage tanks of reactive materials, and the effectiveness of the implementation of the LDAR in the installations involving reactive materials.
The study selected a typical coking enterprise to carry out the characterization of unit VOCs emissions for four production units with high active volatile organic compounds(VOCs) components, namely, phenol refining, Gumarone, asphalt coke, and tar naphthalene. Unit VOCs exhaust was collected using a Suma tank, and 106 VOCs components were characterized and quantified by gas chromatography-mass spectrometry(GC-MS), and the contribution of each unit's VOCs emission to the generation of O3 in the atmosphere was calculated using the maximum incremental reactivity(MIR). The results showed that: 1) aromatic hydrocarbons, halogenated hydrocarbons, and oxygenated VOCs(OVOCs) were the main featured components of the four units, and the sum of mass fractions accounted for 92.33% to 95.38%. 2) The sum of mass fractions of the top 10 VOCs species ranked by the four units ranged from 90.45 to 93.46%. Among them, benzene, acetone, methylene chloride, ethanol, and toluene were the characteristic species of VOCs emission from coking enterprises. 3) The ozone generation potential(OFP) values of the four units were 278.73 μg/m3 to 426.95 μg/m3, in an order of tar naphthalene unit(426.95 μg/m3)>phenol refining unit(410.43 μg/m3)>asphalt coke unit(294.36 μg/m3)>Gumarone unit(278.73 μg/m3). 4) The contribution of the top 10 species of the four units to OFP ranged from 96.24% to 97.97%. Benzene, toluene, m/p-xylene, ethylene, and acetone were the key active species in the industry. 5) Different coking production units had different species characterizing VOCs emissions, and the active species contributing to OFP varied. The largest active species contributing to OFP from phenol refining unit was m/p-xylene, the largest active species contributing to OFP from Gumarone and asphalt coke unit was ethylene, and the primary active species from tar naphthalene unit was toluene. It is recommended that targeted VOCs emission reduction strategies be formulated based on key active components screened in the study. To control the contribution of VOCs emissions to the OFP in the coking industry, priority should be given to the adoption of targeted measures to control the emissions of characteristic pollutant components in different installation areas, such as focusing on strengthening the collection and treatment of respiratory gases from the storage tanks of reactive materials, and the effectiveness of the implementation of the LDAR in the installations involving reactive materials.
2024, 42(2): 167-174.
doi: 10.13205/j.hjgc.202402020
Abstract:
As a new type of environmental pollutant, microplastics pose a serious threat to the soil ecosystem. Studying the effects of microplastics on soil microorganisms and their functions plays an important role in understanding the harm of microplastic pollution to terrestrial ecosystems. Based on the theory of soil heterogeneity, combining soil physical grouping methods and llumina Miseq high-throughput sequencing technology, this paper analyzed the effect of microplastics on soil microorganisms and their functions in soil with different aggregate-fraction levels. The results showed that microplastics altered the soil microbial community structure by significantly increasing and decreasing the abundance of Actinobacteria and Proteobacteria, respectively. Actinobacteria replaced Proteobacteria as the dominant phylum. Furthermore, the relative abundance levels of pathways related to carbohydrate metabolism, lipid metabolism, xenobiotics biodegradation and metabolism, metabolism of terpenoids and polyketides, and immune disease in microplastic treatments were higher than those in control treatments. The direction of effect of microplastics on bacterial metabolic function was consistent in three aggregate-size fractions, but the degree of effect decreased by the sequence of coarse particulate fraction(0.25 to 2 mm), non-aggregated silt and clay fraction(<0.053 mm) and micro-aggregate fraction(0.053 to 0.25 mm). Among three aggregate-size fractions, specific genes involved in labile-C degradation, recalcitrant-C degradation, organic N conversion, denitrification, and organic P mineralization were significantly enriched in microplastic treatments. The results showed that microplastic could change microbial community structure and function, which might change the ecological function of soil.
As a new type of environmental pollutant, microplastics pose a serious threat to the soil ecosystem. Studying the effects of microplastics on soil microorganisms and their functions plays an important role in understanding the harm of microplastic pollution to terrestrial ecosystems. Based on the theory of soil heterogeneity, combining soil physical grouping methods and llumina Miseq high-throughput sequencing technology, this paper analyzed the effect of microplastics on soil microorganisms and their functions in soil with different aggregate-fraction levels. The results showed that microplastics altered the soil microbial community structure by significantly increasing and decreasing the abundance of Actinobacteria and Proteobacteria, respectively. Actinobacteria replaced Proteobacteria as the dominant phylum. Furthermore, the relative abundance levels of pathways related to carbohydrate metabolism, lipid metabolism, xenobiotics biodegradation and metabolism, metabolism of terpenoids and polyketides, and immune disease in microplastic treatments were higher than those in control treatments. The direction of effect of microplastics on bacterial metabolic function was consistent in three aggregate-size fractions, but the degree of effect decreased by the sequence of coarse particulate fraction(0.25 to 2 mm), non-aggregated silt and clay fraction(<0.053 mm) and micro-aggregate fraction(0.053 to 0.25 mm). Among three aggregate-size fractions, specific genes involved in labile-C degradation, recalcitrant-C degradation, organic N conversion, denitrification, and organic P mineralization were significantly enriched in microplastic treatments. The results showed that microplastic could change microbial community structure and function, which might change the ecological function of soil.
2024, 42(2): 175-181.
doi: 10.13205/j.hjgc.202402021
Abstract:
To investigate the response mechanism of root secretions of Leersia hexandra Swartz to Cr(Ⅵ) and identify the key microorganisms in Cr(Ⅵ) reduction, in this study, the types and contents of organic matters secreted by the roots of L. hexandra in an artificial wetland-microbial fuel cell(CW-MFC) system were studied at six Cr(Ⅵ) treatment levels(0, 40, 60, 80, 100, 120 mg/L). Soil microorganisms in the system were measured simultaneously at the control and optimal chromium treatment concentrations. The results showed that: 1) the effect of chromium stress on the root secretion of L. hexandra showed an increasing trend followed by a decreasing trend during the increase of chromium concentration, with the highest quantity of compounds in the root secretion at a hexavalent chromium treatment concentration of 80 mg/L; 2) the roots of L. hexandra were mainly lipids, alkanes, phenols, alkenes, and alcohols, of which alkanes were the most abundant; 3) hexavalent chromium stress significantly increased the enrichment of Geobacter in the CW-MFC system, which may be the key microorganism associated with chromium reduction and enrichment in L. hexandra.
To investigate the response mechanism of root secretions of Leersia hexandra Swartz to Cr(Ⅵ) and identify the key microorganisms in Cr(Ⅵ) reduction, in this study, the types and contents of organic matters secreted by the roots of L. hexandra in an artificial wetland-microbial fuel cell(CW-MFC) system were studied at six Cr(Ⅵ) treatment levels(0, 40, 60, 80, 100, 120 mg/L). Soil microorganisms in the system were measured simultaneously at the control and optimal chromium treatment concentrations. The results showed that: 1) the effect of chromium stress on the root secretion of L. hexandra showed an increasing trend followed by a decreasing trend during the increase of chromium concentration, with the highest quantity of compounds in the root secretion at a hexavalent chromium treatment concentration of 80 mg/L; 2) the roots of L. hexandra were mainly lipids, alkanes, phenols, alkenes, and alcohols, of which alkanes were the most abundant; 3) hexavalent chromium stress significantly increased the enrichment of Geobacter in the CW-MFC system, which may be the key microorganism associated with chromium reduction and enrichment in L. hexandra.
2024, 42(2): 182-191.
doi: 10.13205/j.hjgc.202402022
Abstract:
To investigate the performance of polypyrrole(PPy) modified electrodes in enhancing the electrokinetic remediation of uranium contaminated soil driven by a microbial fuel cell(MFC), PPy was used to modify the carbon felt electrodes, to investigate the effect of different ratios of PPy modified electrode on the electrical production performance of MFC, as well as the electrokinetic remediation performance on uranium contaminated soil. The results showed that the PPy-modified electrodes enhanced the power generation performance of MFC. The maximum voltage of CP100 reached 164 mV, and the maximum power density was 18.92 mW/m2, which was 29.13% and 43.12% higher than the original carbon felt electrodes, respectively; PPy, as an MFC cathode, enhanced the removal of uranium from soil, and the adsorption rate of uranium in CP50 was about 13 times higher than that in the original carbon felt electrode; MFC, as a power source, effectively drove the migration of uranium from the anode to the cathode in the soil. The maximum removal rate of uranium near the anode of the CP50 experimental group was as high as 56.42%. PPy-modified electrodes can significantly enhance the power generation capacity of microbial fuel cells and uranium removal.
To investigate the performance of polypyrrole(PPy) modified electrodes in enhancing the electrokinetic remediation of uranium contaminated soil driven by a microbial fuel cell(MFC), PPy was used to modify the carbon felt electrodes, to investigate the effect of different ratios of PPy modified electrode on the electrical production performance of MFC, as well as the electrokinetic remediation performance on uranium contaminated soil. The results showed that the PPy-modified electrodes enhanced the power generation performance of MFC. The maximum voltage of CP100 reached 164 mV, and the maximum power density was 18.92 mW/m2, which was 29.13% and 43.12% higher than the original carbon felt electrodes, respectively; PPy, as an MFC cathode, enhanced the removal of uranium from soil, and the adsorption rate of uranium in CP50 was about 13 times higher than that in the original carbon felt electrode; MFC, as a power source, effectively drove the migration of uranium from the anode to the cathode in the soil. The maximum removal rate of uranium near the anode of the CP50 experimental group was as high as 56.42%. PPy-modified electrodes can significantly enhance the power generation capacity of microbial fuel cells and uranium removal.
2024, 42(2): 192-198.
doi: 10.13205/j.hjgc.202402023
Abstract:
Microbial reduction of Cr(Ⅵ) to Cr(Ⅲ) is a promising method for remediation of chromium-contaminated soil. Molecular biology was used to identify the species of the strain, and the in situ remediation effect of hexavalent chromium was evaluated through laboratory tests and physical simulation experiments. The results showed that the 16S rDNA full-length sequence of the isolated strain capable of reducing Cr(Ⅵ) was analyzed in Ezbiocloud data, and the similarity was 98.89% with Desulfovibrio desulfuricans DSM 642T, named D. desulfuricans S-7. The most suitable growth temperature for D. desulfuricans S-7 was 30 ℃, while the most suitable pH was 7.0, and the suitable NaCl concentration was 0 to 10%. The results showed that the removal rate of 25 mg/L Cr(Ⅵ) was 79.74%, and the growth and reproduction of the strain was inhibited under an initial 100 mg/L of Cr(Ⅵ). The simulation experiment results revealed Cr(Ⅵ) concentration in the soil changed from 50.0 mg/kg to 3.1 mg/kg, and its removal rate reached 93.8%, while the remediated soil could meet China's national standard, GB 36600—2018, for Class 1 development land. This study showed that D. Desulfurians S-7 can effectively remediate Cr(Ⅵ) contaminated soil in anaerobic environment, providing a new alternative for in-situ remediation of deep-layer Cr(Ⅵ) contaminated soil.
Microbial reduction of Cr(Ⅵ) to Cr(Ⅲ) is a promising method for remediation of chromium-contaminated soil. Molecular biology was used to identify the species of the strain, and the in situ remediation effect of hexavalent chromium was evaluated through laboratory tests and physical simulation experiments. The results showed that the 16S rDNA full-length sequence of the isolated strain capable of reducing Cr(Ⅵ) was analyzed in Ezbiocloud data, and the similarity was 98.89% with Desulfovibrio desulfuricans DSM 642T, named D. desulfuricans S-7. The most suitable growth temperature for D. desulfuricans S-7 was 30 ℃, while the most suitable pH was 7.0, and the suitable NaCl concentration was 0 to 10%. The results showed that the removal rate of 25 mg/L Cr(Ⅵ) was 79.74%, and the growth and reproduction of the strain was inhibited under an initial 100 mg/L of Cr(Ⅵ). The simulation experiment results revealed Cr(Ⅵ) concentration in the soil changed from 50.0 mg/kg to 3.1 mg/kg, and its removal rate reached 93.8%, while the remediated soil could meet China's national standard, GB 36600—2018, for Class 1 development land. This study showed that D. Desulfurians S-7 can effectively remediate Cr(Ⅵ) contaminated soil in anaerobic environment, providing a new alternative for in-situ remediation of deep-layer Cr(Ⅵ) contaminated soil.
2024, 42(2): 199-210.
doi: 10.13205/j.hjgc.202402024
Abstract:
The synergistic effects of climate change and human activities on ecosystem changes are difficult to distinguish. Focusing on this scientific issue, this study uses Hainan Island as a case study to measure the residuals of actual and potential trends in ecological quality, and quantify the relative contributions of climate factors and human activities with the residual trend method. The results show that the overall ecological quality of Hainan Island has been on an upward trend from 2002 to 2020, with 54.09% of the regional ecological quality showing a significant improvement trend, and 4.33% showing a significant decline trend. The contribution rate of human activities to the change in ecological quality on Hainan Island is 85.93%(P<0.05), while the contribution rate of climate change is 14.07%(P<0.05).Human activities have played a dominant role in the change of ecological quality on Hainan Island. Areas experiencing ecological quality improvement have seen a rise in forest ecosystems and a corresponding decline in farmland ecosystems. The main anthropogenic activities responsible for this are the sequential implementation of coastal defense forest construction, commercial plantation establishment, and the delineation of ecological protection red lines, such as Lingao County. Areas experiencing a decline in ecological quality have witnessed a reduction in forest ecosystems accompanied by an expansion of farmland and urban ecosystems. The primary human activity leading to this change is land reclamation and urban development through construction activities, such as Haikou. This study is of great significance for the scientific management of ecosystems and the response to climate change.
The synergistic effects of climate change and human activities on ecosystem changes are difficult to distinguish. Focusing on this scientific issue, this study uses Hainan Island as a case study to measure the residuals of actual and potential trends in ecological quality, and quantify the relative contributions of climate factors and human activities with the residual trend method. The results show that the overall ecological quality of Hainan Island has been on an upward trend from 2002 to 2020, with 54.09% of the regional ecological quality showing a significant improvement trend, and 4.33% showing a significant decline trend. The contribution rate of human activities to the change in ecological quality on Hainan Island is 85.93%(P<0.05), while the contribution rate of climate change is 14.07%(P<0.05).Human activities have played a dominant role in the change of ecological quality on Hainan Island. Areas experiencing ecological quality improvement have seen a rise in forest ecosystems and a corresponding decline in farmland ecosystems. The main anthropogenic activities responsible for this are the sequential implementation of coastal defense forest construction, commercial plantation establishment, and the delineation of ecological protection red lines, such as Lingao County. Areas experiencing a decline in ecological quality have witnessed a reduction in forest ecosystems accompanied by an expansion of farmland and urban ecosystems. The primary human activity leading to this change is land reclamation and urban development through construction activities, such as Haikou. This study is of great significance for the scientific management of ecosystems and the response to climate change.
2024, 42(2): 211-219.
doi: 10.13205/j.hjgc.202402025
Abstract:
As an important infrastructure for the irrigation of farmland in plain regions, small irrigation pumping stations are small in scale but large in number. This paper analyzes the full life cycle carbon emission accounting of the irrigation pumping stations from the perspective of ‘dual carbon', which is of great significance for achieving its sustainable development and promoting efficient of water extraction. Based on the carbon footprint theory, this paper adopts a hybrid life cycle assessment method, and divides the whole life cycle of an irrigation pumping station into five stages: material and equipment production, material and equipment transportation, construction, operation and maintenance, and demolition. This study analyzes the carbon emission law of irrigation pumping stations in the whole process of construction, operation, and management, and establishes a carbon emission model accounting method, including the accounting principle, research ideas, calculation process, and the accounting formula, etc. The results show that the total carbon emissions of the six irrigation pumping stations are 402.87, 34.30, 849.37, 140.93, 1645.56, 312.89 t CO2e, and the annual carbon emission coefficients per unit of irrigated area are 331, 147, 681, 144, 202, 126 kg CO2e/(hm2·a)), respectively; the carbon emissions of each stage vary greatly, with the largest emissions coming from the operation and maintenance phase(62.57%) and the material and equipment production phase(26.64%), while emissions from the construction phase(5.32%), the dismantling and scrapping phase(4.78%) and the material and equipment transportation phase(0.69%) are relatively smaller. Carbon emissions are influenced by the characteristics of irrigation, pumping station size, irrigation area, irrigated crops, and their water consumption, pumping head, power supply method, etc., and show some variability; the power supply method shows greater variability, with solar PV alone showing lower carbon emissions than uniform grid power supply in comparison, and the former type has the highest emissions during the construction phase(56.67%), followed by the operation and maintenance phase(19.04%). The uncertainty analysis of the parameters shows that the value of the lifetime of the structure is the most sensitive to the carbon emission accounting, and should be considered in the measurement of the actual and comprehensive consideration of the norms to make reasonable values. This has led to targeted carbon reduction measures for different types of irrigation pumping stations at different stages of their carbon emission characteristics. The research results provide a technical reference for scientific accounting of the carbon footprint of irrigation pumping stations, building green and economical water infrastructure, and promoting low-carbon development in rural water resources.
As an important infrastructure for the irrigation of farmland in plain regions, small irrigation pumping stations are small in scale but large in number. This paper analyzes the full life cycle carbon emission accounting of the irrigation pumping stations from the perspective of ‘dual carbon', which is of great significance for achieving its sustainable development and promoting efficient of water extraction. Based on the carbon footprint theory, this paper adopts a hybrid life cycle assessment method, and divides the whole life cycle of an irrigation pumping station into five stages: material and equipment production, material and equipment transportation, construction, operation and maintenance, and demolition. This study analyzes the carbon emission law of irrigation pumping stations in the whole process of construction, operation, and management, and establishes a carbon emission model accounting method, including the accounting principle, research ideas, calculation process, and the accounting formula, etc. The results show that the total carbon emissions of the six irrigation pumping stations are 402.87, 34.30, 849.37, 140.93, 1645.56, 312.89 t CO2e, and the annual carbon emission coefficients per unit of irrigated area are 331, 147, 681, 144, 202, 126 kg CO2e/(hm2·a)), respectively; the carbon emissions of each stage vary greatly, with the largest emissions coming from the operation and maintenance phase(62.57%) and the material and equipment production phase(26.64%), while emissions from the construction phase(5.32%), the dismantling and scrapping phase(4.78%) and the material and equipment transportation phase(0.69%) are relatively smaller. Carbon emissions are influenced by the characteristics of irrigation, pumping station size, irrigation area, irrigated crops, and their water consumption, pumping head, power supply method, etc., and show some variability; the power supply method shows greater variability, with solar PV alone showing lower carbon emissions than uniform grid power supply in comparison, and the former type has the highest emissions during the construction phase(56.67%), followed by the operation and maintenance phase(19.04%). The uncertainty analysis of the parameters shows that the value of the lifetime of the structure is the most sensitive to the carbon emission accounting, and should be considered in the measurement of the actual and comprehensive consideration of the norms to make reasonable values. This has led to targeted carbon reduction measures for different types of irrigation pumping stations at different stages of their carbon emission characteristics. The research results provide a technical reference for scientific accounting of the carbon footprint of irrigation pumping stations, building green and economical water infrastructure, and promoting low-carbon development in rural water resources.
2024, 42(2): 220-229.
doi: 10.13205/j.hjgc.202402026
Abstract:
Energy efficiency is one of the key evaluation indicators for construction and operation of EU WtE plants. The EU WtE industry has a relatively complete energy efficiency evaluation system, supporting policies and corresponding techniques The EU Waste Framework Directive(2008/98/EC) proposes the concept of European Waste Hierarchy and specifies the priority of treatment methods. In addition, the calculation formula of energy efficiency evaluation index R1 and its minimum value has been established to evaluate whether EU WtE plants achieve the hierarchy of recovery in European Waste Hierarchy. Data shows that most WtE plants in EU have relatively abundant heat user/distribution network and can adopt co-generation, and the overall energy efficiency level is high, with more than 85% of WtE from municipal solid waste(MSW) is classified as recovery. The energy efficiency of MSW WtE plants in China was calculated using the R1 method. The results show that with the application of related techniques such as high parameter boiler units and large-scale grates in China, the energy efficiency of MSW WtE plants has significantly improved. However, WtE plants in China are with main purpose of power generation, and the energy efficiency is lower than that of the EU. Therefore, it is worth learning from the EU experience of reasonably adopting co-generation and related improvement techniques as well as gradually improving the energy efficiency evaluation system.
Energy efficiency is one of the key evaluation indicators for construction and operation of EU WtE plants. The EU WtE industry has a relatively complete energy efficiency evaluation system, supporting policies and corresponding techniques The EU Waste Framework Directive(2008/98/EC) proposes the concept of European Waste Hierarchy and specifies the priority of treatment methods. In addition, the calculation formula of energy efficiency evaluation index R1 and its minimum value has been established to evaluate whether EU WtE plants achieve the hierarchy of recovery in European Waste Hierarchy. Data shows that most WtE plants in EU have relatively abundant heat user/distribution network and can adopt co-generation, and the overall energy efficiency level is high, with more than 85% of WtE from municipal solid waste(MSW) is classified as recovery. The energy efficiency of MSW WtE plants in China was calculated using the R1 method. The results show that with the application of related techniques such as high parameter boiler units and large-scale grates in China, the energy efficiency of MSW WtE plants has significantly improved. However, WtE plants in China are with main purpose of power generation, and the energy efficiency is lower than that of the EU. Therefore, it is worth learning from the EU experience of reasonably adopting co-generation and related improvement techniques as well as gradually improving the energy efficiency evaluation system.
2024, 42(2): 230-238.
doi: 10.13205/j.hjgc.202402027
Abstract:
Continuous and stable socioeconomic development and improvement of the resident's living conditions in China have resulted in the great generation of municipal solid waste(MSW), which becomes a major barrier toward the sustainable development of cities. This study takes Huzhou in East China, the birthplace of President Jinping Xi's well-known remarks “Lucid Waters and Lush Mountains Are Invaluable Assets”, as well as a national pilot city for implementing “Zero-waste City” practice, as an example. This study systematically described the design and optimization of each functional unit of the intelligent platform, the operation and maintenance, particularly the management level of MSW by an intelligent platform supported by big data and information technology. Based on the inventory data of the generation, classification, collection, transportation, utilization, and disposal of MSW in Huzhou in recent 5 years and its evolution trend, the environmental benefits measured by carbon emission equivalence, from a waste reduction perspective since using the intelligent platform, has been evaluated by using life cycle assessment method. The promotion of smart or intelligent measures for the classification and management of MSW in Huzhou can provide a good reference for other cities.
Continuous and stable socioeconomic development and improvement of the resident's living conditions in China have resulted in the great generation of municipal solid waste(MSW), which becomes a major barrier toward the sustainable development of cities. This study takes Huzhou in East China, the birthplace of President Jinping Xi's well-known remarks “Lucid Waters and Lush Mountains Are Invaluable Assets”, as well as a national pilot city for implementing “Zero-waste City” practice, as an example. This study systematically described the design and optimization of each functional unit of the intelligent platform, the operation and maintenance, particularly the management level of MSW by an intelligent platform supported by big data and information technology. Based on the inventory data of the generation, classification, collection, transportation, utilization, and disposal of MSW in Huzhou in recent 5 years and its evolution trend, the environmental benefits measured by carbon emission equivalence, from a waste reduction perspective since using the intelligent platform, has been evaluated by using life cycle assessment method. The promotion of smart or intelligent measures for the classification and management of MSW in Huzhou can provide a good reference for other cities.
2024, 42(2): 239-246.
doi: 10.13205/j.hjgc.202402028
Abstract:
On April 24, 2022, the Ministry of Ecology and Environment of China announced the construction list of "waste-free city" during the 14th Five-Year Plan period. As the key field of social governance, the accurate classification and treatment of community household waste sources is a key link affecting the construction and development of "waste-free city". Therefore, it is necessary to promote the integration of community sanitation and establish a smart, scientific, fine, and clean infrastructure system for intelligent classification of community household garbage. Relevant studies show that with the gradual implementation of garbage classification policies, regulations and documents, the proportion of all kinds of household garbage is also gradually changing. Among them, the proportion of recyclables, kitchen waste and harmful waste is gradually increasing, while the proportion of other garbage is gradually decreasing. Meanwhile, the improvement of the purity of kitchen waste also lays a foundation for its resource utilization beyond incineration and power generation. It analyzes the characteristics of typical residential communities and the prominent problems existing in the classification, transport, and treatment of domestic garbage inside them, focusing on the standardized, modular, and integrated intelligent garbage classification equipment and AI classification management, scheduling and maintenance platform, and puts forward the configuration principles of intelligent garbage classification infrastructure system in typical communities in Majuqiao Town of Tongzhou District, Beijing. This study can provide a reference and basis for promoting the planning and construction of intelligent garbage sorting and clean collection systems in urban communities in Beijing, Tianjin, Hebei and other areas in China.
On April 24, 2022, the Ministry of Ecology and Environment of China announced the construction list of "waste-free city" during the 14th Five-Year Plan period. As the key field of social governance, the accurate classification and treatment of community household waste sources is a key link affecting the construction and development of "waste-free city". Therefore, it is necessary to promote the integration of community sanitation and establish a smart, scientific, fine, and clean infrastructure system for intelligent classification of community household garbage. Relevant studies show that with the gradual implementation of garbage classification policies, regulations and documents, the proportion of all kinds of household garbage is also gradually changing. Among them, the proportion of recyclables, kitchen waste and harmful waste is gradually increasing, while the proportion of other garbage is gradually decreasing. Meanwhile, the improvement of the purity of kitchen waste also lays a foundation for its resource utilization beyond incineration and power generation. It analyzes the characteristics of typical residential communities and the prominent problems existing in the classification, transport, and treatment of domestic garbage inside them, focusing on the standardized, modular, and integrated intelligent garbage classification equipment and AI classification management, scheduling and maintenance platform, and puts forward the configuration principles of intelligent garbage classification infrastructure system in typical communities in Majuqiao Town of Tongzhou District, Beijing. This study can provide a reference and basis for promoting the planning and construction of intelligent garbage sorting and clean collection systems in urban communities in Beijing, Tianjin, Hebei and other areas in China.
2024, 42(2): 247-254.
doi: 10.13205/j.hjgc.202402029
Abstract:
To study the lipotoxicity of polyfluoroalkyl phosphate diesters(DiPAPs) to zebrafish, firstly, a three-dimensional quantitative structure-activity relationship(3D-QSAR) model of the binding of 15 perfluoroalkyl and polyfluoroalkyl substances(PFASs) with peroxisome proliferator-activated receptor β(PPARβ) was developed to predict the binding affinity of 6:2 and 8:2 DiPAPs, respectively. Afterward, the interactions between 6:2 and 8:2 DiPAPs and PPARβ were studied based on molecular docking. Finally, to verify the predicted results of the 3D-QSAR model, the effects of 6:2 and 8:2 DiPAPs on the expression of zebrafish PPARβ were investigated. The results show that the 50% inhibition concentration(pIC50) of 6:2 and 8:2 DiPAPs was 3.73 mol/L and 3.63 mol/L, respectively, indicating their potential peroxisome proliferation activities. 6:2 and 8:2 DiPAPs could bind to PPARβ mainly through hydrogen bonding and hydrophobic interaction, and the binding activity of 6:2 DiPAP was higher than that of 8:2 DiPAP. After the exposure to 6:2 and 8:2 DiPAPs, the expressions of PPARβ were both significantly up-regulated. The expression in the 50 ng/L 6:2 DiPAP group was significantly higher than that in the 50 ng/L 8:2 DiPAP group, which was concordant with the predicted results by the 3D-QSAR model. In conclusion, 6:2 and 8:2 DiPAPs could induce lipotoxicity by affecting the expressions of zebrafish PPARβ. This study can provide scientific pieces of evidence for risk assessment of DiPAPs, such as a class of emerging PFASs, in the aquatic environment.
To study the lipotoxicity of polyfluoroalkyl phosphate diesters(DiPAPs) to zebrafish, firstly, a three-dimensional quantitative structure-activity relationship(3D-QSAR) model of the binding of 15 perfluoroalkyl and polyfluoroalkyl substances(PFASs) with peroxisome proliferator-activated receptor β(PPARβ) was developed to predict the binding affinity of 6:2 and 8:2 DiPAPs, respectively. Afterward, the interactions between 6:2 and 8:2 DiPAPs and PPARβ were studied based on molecular docking. Finally, to verify the predicted results of the 3D-QSAR model, the effects of 6:2 and 8:2 DiPAPs on the expression of zebrafish PPARβ were investigated. The results show that the 50% inhibition concentration(pIC50) of 6:2 and 8:2 DiPAPs was 3.73 mol/L and 3.63 mol/L, respectively, indicating their potential peroxisome proliferation activities. 6:2 and 8:2 DiPAPs could bind to PPARβ mainly through hydrogen bonding and hydrophobic interaction, and the binding activity of 6:2 DiPAP was higher than that of 8:2 DiPAP. After the exposure to 6:2 and 8:2 DiPAPs, the expressions of PPARβ were both significantly up-regulated. The expression in the 50 ng/L 6:2 DiPAP group was significantly higher than that in the 50 ng/L 8:2 DiPAP group, which was concordant with the predicted results by the 3D-QSAR model. In conclusion, 6:2 and 8:2 DiPAPs could induce lipotoxicity by affecting the expressions of zebrafish PPARβ. This study can provide scientific pieces of evidence for risk assessment of DiPAPs, such as a class of emerging PFASs, in the aquatic environment.
