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2024, Volume 42, Issue 10
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2024,
42(10):
1-10.
doi: 10.13205/j.hjgc.202410001
Abstract:
The ecological utilization of reclaimed water can alleviate water resource shortages and improve urban ecological environments. However, there are currently several key issues waiting for answers or solutions, including potential ecological effects of reclaimed water, a complete water quality indicator system and threshold-determining methods, an optimization of advanced treatment processes and ecological buffer zone construction, and an integrated evaluation system combining economic costs, energy conservation, carbon reduction, and environmental benefits. Therefore, it is an urgent need to establish effective technologies and methods for rapid assessment of water quality for ecological safety, clarify the ecological effects of reclaimed water, improve the indicator system for reclaimed water quality standards, develop methods for determining safety thresholds under different environmental characteristics, green technologies for the removal of key risk factors such as new pollutants and pathogenic microorganisms, clarify the water quality purification mechanisms, construction principles, and methods of the ecological buffer zones, and create comprehensive evaluation methods for the environmental benefits of reclaimed water ecological utilization as well as optimization methods for reclaimed water ecological utilization strategies.
The ecological utilization of reclaimed water can alleviate water resource shortages and improve urban ecological environments. However, there are currently several key issues waiting for answers or solutions, including potential ecological effects of reclaimed water, a complete water quality indicator system and threshold-determining methods, an optimization of advanced treatment processes and ecological buffer zone construction, and an integrated evaluation system combining economic costs, energy conservation, carbon reduction, and environmental benefits. Therefore, it is an urgent need to establish effective technologies and methods for rapid assessment of water quality for ecological safety, clarify the ecological effects of reclaimed water, improve the indicator system for reclaimed water quality standards, develop methods for determining safety thresholds under different environmental characteristics, green technologies for the removal of key risk factors such as new pollutants and pathogenic microorganisms, clarify the water quality purification mechanisms, construction principles, and methods of the ecological buffer zones, and create comprehensive evaluation methods for the environmental benefits of reclaimed water ecological utilization as well as optimization methods for reclaimed water ecological utilization strategies.
2024,
42(10):
11-16.
doi: 10.13205/j.hjgc.202410002
Abstract:
Aiming at the problem of ultra-low fluorine discharge from alkaline high-fluorine wastewater produced by a rare earth chemical plant, the technical scheme and condition optimization of fluorine removal was studied. The process scheme was proposed, and an engineering design was carried out. The results showed that the calcium fluoride chemical precipitation method was more suitable for removing fluoride from high-fluorine wastewater. The increase in the calcium-fluorine ratio helped improve the effect of chemical precipitation. However, excessive CaCl2 dosing (Ca∶F>0.7) would lead to a sharp increase in sludge production, while coagulation sedimentation was more suitable for further deep fluoride removal of low-fluorine wastewater (<20 mg F/L). When the molar ratio of aluminum to fluorine was 13.5, and the initial pH was 6, the fluorine concentration of the effluent could be stabilized at about 0.37 mg/L. The ultra-low discharge process plan for high-fluorine wastewater was proposed, and the engineering design was carried out. The high-calcium acid wastewater produced by the enterprise was used to pretreat the alkaline high-fluoride wastewater, and then the chemical precipitation-coagulation precipitation coupling process was used to stabilize the fluorine concentration of the effluent, to meet the limiting value of the emission standard of 1.5 mg/L below.
Aiming at the problem of ultra-low fluorine discharge from alkaline high-fluorine wastewater produced by a rare earth chemical plant, the technical scheme and condition optimization of fluorine removal was studied. The process scheme was proposed, and an engineering design was carried out. The results showed that the calcium fluoride chemical precipitation method was more suitable for removing fluoride from high-fluorine wastewater. The increase in the calcium-fluorine ratio helped improve the effect of chemical precipitation. However, excessive CaCl2 dosing (Ca∶F>0.7) would lead to a sharp increase in sludge production, while coagulation sedimentation was more suitable for further deep fluoride removal of low-fluorine wastewater (<20 mg F/L). When the molar ratio of aluminum to fluorine was 13.5, and the initial pH was 6, the fluorine concentration of the effluent could be stabilized at about 0.37 mg/L. The ultra-low discharge process plan for high-fluorine wastewater was proposed, and the engineering design was carried out. The high-calcium acid wastewater produced by the enterprise was used to pretreat the alkaline high-fluoride wastewater, and then the chemical precipitation-coagulation precipitation coupling process was used to stabilize the fluorine concentration of the effluent, to meet the limiting value of the emission standard of 1.5 mg/L below.
2024,
42(10):
17-25.
doi: 10.13205/j.hjgc.202410003
Abstract:
In this study, a novel type of highly efficient single-stage nitrogen removal process (Hesin) was developed based on the principle of partial nitrification-denitrification. The total volume of the Hesin reactor was 300 m3. After 185 days of start-up and operation, the Hesin process was successfully achieved for the efficient treatment of food wastewater anaerobic digestate. During the stable operation period, the hydraulic retention time (HRT) was 100 h, the wastewater volume was 60 m3/d, and the dissolved oxygen (DO) was limited to about 0.5 mg/L. The results showed that the average total nitrogen removal rate could reach 0.31 kg/(m3·d), the average total nitrogen removal efficiency could reach 95.55%, the concentration of total nitrogen in the effluent was less than 100 mg/L, and the average COD removal efficiency was 87.26%, 3 times that of the traditional process in the treatment of kitchen wastewater. The sludge concentration could reach 8.85 g/L after acclimation by the Hesin process, and the sludge particle size increased obviously. Through the analysis of microbial community structure by high-throughput sequencing, it was found that obvious community succession occurred during the domestication process, and the nitrite-oxidizing bacteria Nitrospirales were successfully inhibited and washed out. The results were consistent with the accumulation of nitrite during the operation of the Hesin process, indicating that the partial nitrification-denitrification process was successfully realized. This study can provide new solutions and technical support for the removal of total nitrogen in food wastewater anaerobic digestate.
In this study, a novel type of highly efficient single-stage nitrogen removal process (Hesin) was developed based on the principle of partial nitrification-denitrification. The total volume of the Hesin reactor was 300 m3. After 185 days of start-up and operation, the Hesin process was successfully achieved for the efficient treatment of food wastewater anaerobic digestate. During the stable operation period, the hydraulic retention time (HRT) was 100 h, the wastewater volume was 60 m3/d, and the dissolved oxygen (DO) was limited to about 0.5 mg/L. The results showed that the average total nitrogen removal rate could reach 0.31 kg/(m3·d), the average total nitrogen removal efficiency could reach 95.55%, the concentration of total nitrogen in the effluent was less than 100 mg/L, and the average COD removal efficiency was 87.26%, 3 times that of the traditional process in the treatment of kitchen wastewater. The sludge concentration could reach 8.85 g/L after acclimation by the Hesin process, and the sludge particle size increased obviously. Through the analysis of microbial community structure by high-throughput sequencing, it was found that obvious community succession occurred during the domestication process, and the nitrite-oxidizing bacteria Nitrospirales were successfully inhibited and washed out. The results were consistent with the accumulation of nitrite during the operation of the Hesin process, indicating that the partial nitrification-denitrification process was successfully realized. This study can provide new solutions and technical support for the removal of total nitrogen in food wastewater anaerobic digestate.
2024,
42(10):
26-32.
doi: 10.13205/j.hjgc.202410004
Abstract:
To study the efficient reduction of pollutants in inflow rivers, this paper took the Tiegang Reservoir in Bao’an District of Shenzhen as the research object, combined with the water quality of inflow rivers and the implementation status of the existing water quality improvement projects, proposed a process of "regulation and storage + treatment + transferring" to treat non-point source pollution in the basin, and analyzed the treatment results of this process. The results showed that the pollutant concentration of the four rivers flowing into the Tiegang Reservoir exceeded the Class Ⅴ in Surface Water Quality Standard of China (GB 3838—2002),and in the river basin, the non-point source pollution of 65000 m3 of initial rainfall water had not been resolved. The project set up six storage tanks to collect the 65000 m3 of initial rainfall water. After storage and regulation, the process of "A2/O biological reaction tank + high-density sedimentation tank + modular open channel ultraviolet disinfection device" was adopted for treatment; after treatment, the removal rate of COD in the initial rain reached 86.9%, and the removal rates of BOD5, ammonia nitrogen, total nitrogen, and total phosphorus all reached more than 94%. The water quality met the class Ⅳ surface water quality standard, and could directly feed the reservoir inflow river.
To study the efficient reduction of pollutants in inflow rivers, this paper took the Tiegang Reservoir in Bao’an District of Shenzhen as the research object, combined with the water quality of inflow rivers and the implementation status of the existing water quality improvement projects, proposed a process of "regulation and storage + treatment + transferring" to treat non-point source pollution in the basin, and analyzed the treatment results of this process. The results showed that the pollutant concentration of the four rivers flowing into the Tiegang Reservoir exceeded the Class Ⅴ in Surface Water Quality Standard of China (GB 3838—2002),and in the river basin, the non-point source pollution of 65000 m3 of initial rainfall water had not been resolved. The project set up six storage tanks to collect the 65000 m3 of initial rainfall water. After storage and regulation, the process of "A2/O biological reaction tank + high-density sedimentation tank + modular open channel ultraviolet disinfection device" was adopted for treatment; after treatment, the removal rate of COD in the initial rain reached 86.9%, and the removal rates of BOD5, ammonia nitrogen, total nitrogen, and total phosphorus all reached more than 94%. The water quality met the class Ⅳ surface water quality standard, and could directly feed the reservoir inflow river.
2024,
42(10):
33-40.
doi: 10.13205/j.hjgc.202410005
Abstract:
Due to the differences in the process and extent of urbanization, large differences of non-point source pollution appeared in different regions. To study the distribution characteristics and environmental effects of urban and non-urban non-point source pollution in typical river basins, this study selected two typical hilly and mountainous areas of the Yangtze River basin (Yongchuan District, Chongqing) and plain river network area (Jintan District, Changzhou, Jiangsu) as research objects. The spatial and temporal distribution characteristics of urban and non-urban non-point source pollution in different landforms were analyzed. Combined with rainfall characteristics, the correlation between rainfall and urban and non-urban non-point source pollutants was explored. The results showed that the proportion of urban non-point source pollution was much higher than that in non-urban areas in the two regions, especially in winter (from November to March) when there is less rainfall in the hilly and mountainous area. The monthly responses of those two regions to non-point source pollutants were different. Generally, the concentrations of different forms of nitrogen and phosphorus in the hilly and mountainous area were slightly higher than those in plain river network area. In the hilly and mountainous area, the highest nitrogen and phosphorus concentrations of different forms in urban areas appeared in December, while the highest concentrations in non-urban areas appeared in August. However, the highest nitrogen and phosphorus concentrations of different forms in plain river network area appeared in November. In addition, the permanganate index of non-urban areas was higher than that of urban areas in autumn and winter. Rainfall is positively correlated with most non-urban non-point source pollutants in the two regions, indicating that rainfall is one of the main influencing factors of non-urban non-point source pollution. However, the correlation between rainfall and different non-point source pollutants can be divided into long-term response and instantaneous effect. 10-year average annual rainfall is positively correlated with most non-urban non-point source pollutants in the two regions, while rainfall during the sampling time is positively correlated with most urban non-point source pollutants in plain river network area. This study reveals the non-negligible role of urban non-point source pollution in the hilly and mountainous area and the plain river network area. Analyzing the spatial and temporal distribution characteristics and emission characteristics of non-point source pollutants from different sources is important for scientific prevention and control of non-point source pollution.
Due to the differences in the process and extent of urbanization, large differences of non-point source pollution appeared in different regions. To study the distribution characteristics and environmental effects of urban and non-urban non-point source pollution in typical river basins, this study selected two typical hilly and mountainous areas of the Yangtze River basin (Yongchuan District, Chongqing) and plain river network area (Jintan District, Changzhou, Jiangsu) as research objects. The spatial and temporal distribution characteristics of urban and non-urban non-point source pollution in different landforms were analyzed. Combined with rainfall characteristics, the correlation between rainfall and urban and non-urban non-point source pollutants was explored. The results showed that the proportion of urban non-point source pollution was much higher than that in non-urban areas in the two regions, especially in winter (from November to March) when there is less rainfall in the hilly and mountainous area. The monthly responses of those two regions to non-point source pollutants were different. Generally, the concentrations of different forms of nitrogen and phosphorus in the hilly and mountainous area were slightly higher than those in plain river network area. In the hilly and mountainous area, the highest nitrogen and phosphorus concentrations of different forms in urban areas appeared in December, while the highest concentrations in non-urban areas appeared in August. However, the highest nitrogen and phosphorus concentrations of different forms in plain river network area appeared in November. In addition, the permanganate index of non-urban areas was higher than that of urban areas in autumn and winter. Rainfall is positively correlated with most non-urban non-point source pollutants in the two regions, indicating that rainfall is one of the main influencing factors of non-urban non-point source pollution. However, the correlation between rainfall and different non-point source pollutants can be divided into long-term response and instantaneous effect. 10-year average annual rainfall is positively correlated with most non-urban non-point source pollutants in the two regions, while rainfall during the sampling time is positively correlated with most urban non-point source pollutants in plain river network area. This study reveals the non-negligible role of urban non-point source pollution in the hilly and mountainous area and the plain river network area. Analyzing the spatial and temporal distribution characteristics and emission characteristics of non-point source pollutants from different sources is important for scientific prevention and control of non-point source pollution.
2024,
42(10):
41-49.
doi: 10.13205/j.hjgc.202410006
Abstract:
The crude oil phase of reservoir-produced fluid has been considered as an ideal environment for obtaining crude oil-degrading bacteria in recent years, but there is little research on microbial isolation from the crude oil phase. In this study, the microbial community structure in the aqueous-oil phase of the produced fluid from six oil wells located in the North China Oilfield was compared. Then, the endogenous community in the six crude oil phases was enriched, respectively. At the same time, the community succession in the process of enrichment was dynamically tracked. Finally, the response of the enriched communities to continuous disturbance of environmental factors was investigated. The results showed that the microbial diversity and richness in the crude oil phase were higher than those in the aqueous phase, and there were significant differences in the community structure between the two phases. The crude oil phases from well P1#, 92#, and 99# contained 111, 23, and 9 unique OTUs, respectively. After 10 generations of continuous enrichment, the crude oil degradation rates of enriched communities 15#, 92#, and P1# gradually increased and tended to be stable, and the maximum degradation rate was 81.9%, 71.5%, and 63.6%, respectively. The dominant bacteria in the community 15# mainly included Brevibacillus (89.3%), Novibacillus (8.0%), and Bacillus (1.5%), while Brevibacillus was the absolute dominant bacteria (with a relative abundance of 99%) in the community 92# and P1#. Under the multiple disturbances of temperature and oxygen, the microbial composition and abundance of community P1# changed. The dominant Brevibacillus was suppressed while the relative abundance of Paenibacillus and Aneurinibacillus increased, resulting in the accumulation of medium and long chain alkanes (C18 to C29). However, community 15# and 92# can maintain stable ability of alkane degradation. These results indicated that the crude oil phase of the produced liquid can act as a potential microbial source for exploring crude oil-degrading bacteria.
The crude oil phase of reservoir-produced fluid has been considered as an ideal environment for obtaining crude oil-degrading bacteria in recent years, but there is little research on microbial isolation from the crude oil phase. In this study, the microbial community structure in the aqueous-oil phase of the produced fluid from six oil wells located in the North China Oilfield was compared. Then, the endogenous community in the six crude oil phases was enriched, respectively. At the same time, the community succession in the process of enrichment was dynamically tracked. Finally, the response of the enriched communities to continuous disturbance of environmental factors was investigated. The results showed that the microbial diversity and richness in the crude oil phase were higher than those in the aqueous phase, and there were significant differences in the community structure between the two phases. The crude oil phases from well P1#, 92#, and 99# contained 111, 23, and 9 unique OTUs, respectively. After 10 generations of continuous enrichment, the crude oil degradation rates of enriched communities 15#, 92#, and P1# gradually increased and tended to be stable, and the maximum degradation rate was 81.9%, 71.5%, and 63.6%, respectively. The dominant bacteria in the community 15# mainly included Brevibacillus (89.3%), Novibacillus (8.0%), and Bacillus (1.5%), while Brevibacillus was the absolute dominant bacteria (with a relative abundance of 99%) in the community 92# and P1#. Under the multiple disturbances of temperature and oxygen, the microbial composition and abundance of community P1# changed. The dominant Brevibacillus was suppressed while the relative abundance of Paenibacillus and Aneurinibacillus increased, resulting in the accumulation of medium and long chain alkanes (C18 to C29). However, community 15# and 92# can maintain stable ability of alkane degradation. These results indicated that the crude oil phase of the produced liquid can act as a potential microbial source for exploring crude oil-degrading bacteria.
2024,
42(10):
50-55.
doi: 10.13205/j.hjgc.202410007
Abstract:
Inner Mongolia Autonomous Region is an important ecological security barrier in China’s northern border region. Research on the effect of rural sewage treatment in Inner Mongolia Autonomous Region will help ensure regional ecological security and promote the construction of harmonious and beautiful villages. This study surveyed sewage treatment in 585 villages in Inner Mongolia Autonomous Region and analyzed the characteristics of rural sewage production and discharge (including per capita displacement, drainage coefficient, and sewage quality), and the current situation (including treatment scale, process type, and effluent destination) of five sewage treatment methods (including sewage resource utilization relying on toilet conversion, integration into urban sewers, construction of centralized sewage treatment facilities, construction of decentralized sewage treatment facilities, and transport-treatment) in the western, central and eastern regions of Inner Mongolia Autonomous Region. On this basis, three suggestions were put forward to scientifically evaluate the short-term treatment effect and long-term comprehensive benefit of the existing treatment methods, effectively reduce the impact of low temperature in winter and discontinuous drainage on the operation effect of sewage treatment facilities, and reasonably solve the treatment facilities operation problems caused by the shortage of funds and technical strength of operation and maintenance.
Inner Mongolia Autonomous Region is an important ecological security barrier in China’s northern border region. Research on the effect of rural sewage treatment in Inner Mongolia Autonomous Region will help ensure regional ecological security and promote the construction of harmonious and beautiful villages. This study surveyed sewage treatment in 585 villages in Inner Mongolia Autonomous Region and analyzed the characteristics of rural sewage production and discharge (including per capita displacement, drainage coefficient, and sewage quality), and the current situation (including treatment scale, process type, and effluent destination) of five sewage treatment methods (including sewage resource utilization relying on toilet conversion, integration into urban sewers, construction of centralized sewage treatment facilities, construction of decentralized sewage treatment facilities, and transport-treatment) in the western, central and eastern regions of Inner Mongolia Autonomous Region. On this basis, three suggestions were put forward to scientifically evaluate the short-term treatment effect and long-term comprehensive benefit of the existing treatment methods, effectively reduce the impact of low temperature in winter and discontinuous drainage on the operation effect of sewage treatment facilities, and reasonably solve the treatment facilities operation problems caused by the shortage of funds and technical strength of operation and maintenance.
2024,
42(10):
56-64.
doi: 10.13205/j.hjgc.202410008
Abstract:
Among many industrial wastewater treatment technologies, iron-carbon micro-electrolysis technology has the characteristics of no extra power supply, low operating consumption, capability for many kinds of wastewater, high treatment efficiency, simple equipment and easy maintenance. The research progress on the mechanism of iron carbon micro electrolysis, the research results on the optimization of influencing factors, such as initial pH, reaction time, iron carbon ratio, aeration rate and temperature, as well as the application research status of iron carbon micro electrolysis technology in the treatment of typical industrial wastewater such as printing and dyeing, pharmaceutical, coking and papermaking wastewater are reviewed. The bottleneck problems in the application of iron carbon micro electrolysis technology and the corresponding breakthrough direction are also discussed.
Among many industrial wastewater treatment technologies, iron-carbon micro-electrolysis technology has the characteristics of no extra power supply, low operating consumption, capability for many kinds of wastewater, high treatment efficiency, simple equipment and easy maintenance. The research progress on the mechanism of iron carbon micro electrolysis, the research results on the optimization of influencing factors, such as initial pH, reaction time, iron carbon ratio, aeration rate and temperature, as well as the application research status of iron carbon micro electrolysis technology in the treatment of typical industrial wastewater such as printing and dyeing, pharmaceutical, coking and papermaking wastewater are reviewed. The bottleneck problems in the application of iron carbon micro electrolysis technology and the corresponding breakthrough direction are also discussed.
2024,
42(10):
65-72.
doi: 10.13205/j.hjgc.202410009
Abstract:
Different activated carbon (AC) exhibits significant differences in the adsorption and removal of different pollutants. This article comprehensively evaluated the performance of commercial AC in the adsorption and removal of typical gasoline vapor m-xylene, and systematically investigated their adsorption performance. Selecting six ACs with different matrix materials as the research object, the static adsorption experiments were designed and by combining the characterization of physical and chemical properties of activated carbon, the AC with the best adsorption performance was used in dynamic adsorption studies, to explore the influence of gas flow rate, inlet concentration, and bed height on the adsorption performance. The results showed that the specific surface areas of the six ACs were from 851 m2/g to 1851 m2/g, pore volumes were spanning 0.047 m3/g to 0.698 m3/g, average pore sizes were between 3.0 nm and 4.3 nm, and the static adsorption capacities for m-xylene were ranging from 253.5 mg/g to 870.7 mg/g. AC-6 with a micro-mesoporous structure demonstrated the highest static adsorption capacity for m-xylene. It boasted a maximum specific surface area of 1851 m2/g, a pore volume of 0.698 m3/g, and an average pore size of 4.3 nm. Furthermore, AC-6 featured a rich array of surface functional groups, including hydroxyl, carboxyl, and ester groups. In dynamic adsorption experiments with AC-6, increasing the bed height from 0.6 cm to 1.0 cm resulted in a rise in saturated adsorption capacity from 436.6 mg/g to 465.4 mg/g. Increasing the gas flow rate, the saturated adsorption capacity was reduced from 473.1 mg/g to 430.9 mg/g; and increasing the inlet concentration, the saturated adsorption capacity was reduced from 468.0 mg/g to 386.7 mg/g, indicating that the import concentration of m-xylene had a significant impact on the adsorption performance. The adsorption kinetics of AC-6 on m-xylene complied with the Pseudo-first-order kinetic model, and the Langmuir adsorption isotherm model could better describe the adsorption process of AC on m-xylene.
Different activated carbon (AC) exhibits significant differences in the adsorption and removal of different pollutants. This article comprehensively evaluated the performance of commercial AC in the adsorption and removal of typical gasoline vapor m-xylene, and systematically investigated their adsorption performance. Selecting six ACs with different matrix materials as the research object, the static adsorption experiments were designed and by combining the characterization of physical and chemical properties of activated carbon, the AC with the best adsorption performance was used in dynamic adsorption studies, to explore the influence of gas flow rate, inlet concentration, and bed height on the adsorption performance. The results showed that the specific surface areas of the six ACs were from 851 m2/g to 1851 m2/g, pore volumes were spanning 0.047 m3/g to 0.698 m3/g, average pore sizes were between 3.0 nm and 4.3 nm, and the static adsorption capacities for m-xylene were ranging from 253.5 mg/g to 870.7 mg/g. AC-6 with a micro-mesoporous structure demonstrated the highest static adsorption capacity for m-xylene. It boasted a maximum specific surface area of 1851 m2/g, a pore volume of 0.698 m3/g, and an average pore size of 4.3 nm. Furthermore, AC-6 featured a rich array of surface functional groups, including hydroxyl, carboxyl, and ester groups. In dynamic adsorption experiments with AC-6, increasing the bed height from 0.6 cm to 1.0 cm resulted in a rise in saturated adsorption capacity from 436.6 mg/g to 465.4 mg/g. Increasing the gas flow rate, the saturated adsorption capacity was reduced from 473.1 mg/g to 430.9 mg/g; and increasing the inlet concentration, the saturated adsorption capacity was reduced from 468.0 mg/g to 386.7 mg/g, indicating that the import concentration of m-xylene had a significant impact on the adsorption performance. The adsorption kinetics of AC-6 on m-xylene complied with the Pseudo-first-order kinetic model, and the Langmuir adsorption isotherm model could better describe the adsorption process of AC on m-xylene.
2024,
42(10):
73-82.
doi: 10.13205/j.hjgc.202410010
Abstract:
To analyze the pollution characteristics of PM2.5 and O3, the meteorological environment and diffusion of the two pollution processes were simulated and analyzed on the mesoscale region, by using the pollutant data of the national control monitoring stations in Shenyang during the COVID-19 epidemic, and combined with WRF-Chem model. HYSPLIT software was used to analyze the transmission channel, potential source area, and concentration weight of the pollution process. The results showed that PM2.5 concentration had been declining during the three years of the epidemic, and O3 concentration was at an extremely low point in 2021. PM2.5 pollution and O3 pollution fluctuates with seasons. PM2.5 pollution shows obvious seasonal characteristics, more frequent in autumn and winter, and is greatly affected by adverse weather conditions such as temperature inversion, high humidity, high atmospheric stability, and low wind speed. O3 pollution is significantly affected by high temperatures. In January, the external transport of pollutants in Shenyang mainly comes from the north, while the external transport of O3 pollution in spring and summer is mainly affected by the southern Liaoning Province and the Yellow Sea region. The O3 concentration is obviously higher in spring and summer, and lower in autumn and winter, and higher at noon than at night, which is affected by warming and high temperature. High-intensity solar radiation, high-temperature weather, and static weather can induce ozone pollution. Reducing anthropogenic emissions during the epidemic effectively reduces PM2.5 pollution, but has no significant impact on O3 pollution.
To analyze the pollution characteristics of PM2.5 and O3, the meteorological environment and diffusion of the two pollution processes were simulated and analyzed on the mesoscale region, by using the pollutant data of the national control monitoring stations in Shenyang during the COVID-19 epidemic, and combined with WRF-Chem model. HYSPLIT software was used to analyze the transmission channel, potential source area, and concentration weight of the pollution process. The results showed that PM2.5 concentration had been declining during the three years of the epidemic, and O3 concentration was at an extremely low point in 2021. PM2.5 pollution and O3 pollution fluctuates with seasons. PM2.5 pollution shows obvious seasonal characteristics, more frequent in autumn and winter, and is greatly affected by adverse weather conditions such as temperature inversion, high humidity, high atmospheric stability, and low wind speed. O3 pollution is significantly affected by high temperatures. In January, the external transport of pollutants in Shenyang mainly comes from the north, while the external transport of O3 pollution in spring and summer is mainly affected by the southern Liaoning Province and the Yellow Sea region. The O3 concentration is obviously higher in spring and summer, and lower in autumn and winter, and higher at noon than at night, which is affected by warming and high temperature. High-intensity solar radiation, high-temperature weather, and static weather can induce ozone pollution. Reducing anthropogenic emissions during the epidemic effectively reduces PM2.5 pollution, but has no significant impact on O3 pollution.
2024,
42(10):
83-91.
doi: 10.13205/j.hjgc.202410011
Abstract:
Studying the emission generation mechanism and dispersion features in the bottleneck nodes of highway freight can provide a theoretical basis for pollution joint prevention and control in highway emission hotspots. To achieve the dynamic portrayal of spatial-temporal emissions, second-by-second driving data, and heavy-duty diesel vehicle emission test data were collected from Beijing’s key freight road network, then, based on the characterization of congestion formation and dissipation, a quantification index of emission intensity in different driving conditions (deceleration, acceleration, and idling) was designed. Furthermore, an emission spatial-temporal distribution model based on the vehicle specific power was built. Finally, taking the Xiji Comprehensive Inspection Station in Tongzhou District Beijing as a case, we compared the changes in the spatial-temporal emissions(CO2, CO, THC, NOx) before and after the establishment of the station, and the adoption of two emission reduction measures(sampling and enhancing service efficiency). The results showed that the total emissions at the bottleneck nodes were 2.2 to 2.5 times higher than the conventional ones. The queuing area in front of the bottleneck and 0~10 m behind it had the maximum emission intensity, which was 2.1 to 2.9 times higher than the decelerated and bottleneck operating areas. To a certain extent, sampling and enhancing service efficiency can reduce polution emissions. Moreover, both of the emission reduction strategies significantly improve NOx emission reduction effect.
Studying the emission generation mechanism and dispersion features in the bottleneck nodes of highway freight can provide a theoretical basis for pollution joint prevention and control in highway emission hotspots. To achieve the dynamic portrayal of spatial-temporal emissions, second-by-second driving data, and heavy-duty diesel vehicle emission test data were collected from Beijing’s key freight road network, then, based on the characterization of congestion formation and dissipation, a quantification index of emission intensity in different driving conditions (deceleration, acceleration, and idling) was designed. Furthermore, an emission spatial-temporal distribution model based on the vehicle specific power was built. Finally, taking the Xiji Comprehensive Inspection Station in Tongzhou District Beijing as a case, we compared the changes in the spatial-temporal emissions(CO2, CO, THC, NOx) before and after the establishment of the station, and the adoption of two emission reduction measures(sampling and enhancing service efficiency). The results showed that the total emissions at the bottleneck nodes were 2.2 to 2.5 times higher than the conventional ones. The queuing area in front of the bottleneck and 0~10 m behind it had the maximum emission intensity, which was 2.1 to 2.9 times higher than the decelerated and bottleneck operating areas. To a certain extent, sampling and enhancing service efficiency can reduce polution emissions. Moreover, both of the emission reduction strategies significantly improve NOx emission reduction effect.
2024,
42(10):
92-101.
doi: 10.13205/j.hjgc.202410012
Abstract:
To deeply understand the current situation of vehicle emissions in Zhengzhou and improve the level of mobile pollution sources management, a vehicular dynamic emission model based on the traffic flow characteristics and localized emission factors was established by integrating multi-source traffic big data, achieving the real-time calculation of on-road emission. Then a high spatio-temporal resolution on-road emission inventory in Zhengzhou was developed at the hourly and link level. The vehicle emission characteristics were analyzed by vehicle type, ring road, administrative division, and road type, and the measures for vehicle pollution control were proposed. The results showed that passenger cars were the major contributors to CO2, CO, and HC emissions, while NOx and PM emissions mainly came from trucks and coaches. The carbon emissions (including CO2, CO, and HC) in Zhengzhou were mainly concentrated in the area of the 3rd Ring Road, with a gradually decreasing trend from downtown areas to urban fringes. The emissions of NOx and PM were concentrated in ring roads with distinctive banding distribution. The analysis of the emission characteristics of administrative regions showed that the proportion of CO2, CO, and HC emissions in Zhengdong New District and Jinshui District was more prominent, and NOx and PM emissions in Zhongmu County and Xinzheng County were relatively heavier. Additionally, the CO2 emission rate of urban expressways was as high as 3.66 t/(km·d), and the NOx emission intensity on highways was the highest, at 0.017 t/(km·d). The research indicated that Zhengzhou could give priority to promoting green and low-carbon development in the downtown area and enhancing the level of truck pollution control, which contributed to the synergy of pollution and carbon emissions reduction from mobile sources and improvement of air quality.
To deeply understand the current situation of vehicle emissions in Zhengzhou and improve the level of mobile pollution sources management, a vehicular dynamic emission model based on the traffic flow characteristics and localized emission factors was established by integrating multi-source traffic big data, achieving the real-time calculation of on-road emission. Then a high spatio-temporal resolution on-road emission inventory in Zhengzhou was developed at the hourly and link level. The vehicle emission characteristics were analyzed by vehicle type, ring road, administrative division, and road type, and the measures for vehicle pollution control were proposed. The results showed that passenger cars were the major contributors to CO2, CO, and HC emissions, while NOx and PM emissions mainly came from trucks and coaches. The carbon emissions (including CO2, CO, and HC) in Zhengzhou were mainly concentrated in the area of the 3rd Ring Road, with a gradually decreasing trend from downtown areas to urban fringes. The emissions of NOx and PM were concentrated in ring roads with distinctive banding distribution. The analysis of the emission characteristics of administrative regions showed that the proportion of CO2, CO, and HC emissions in Zhengdong New District and Jinshui District was more prominent, and NOx and PM emissions in Zhongmu County and Xinzheng County were relatively heavier. Additionally, the CO2 emission rate of urban expressways was as high as 3.66 t/(km·d), and the NOx emission intensity on highways was the highest, at 0.017 t/(km·d). The research indicated that Zhengzhou could give priority to promoting green and low-carbon development in the downtown area and enhancing the level of truck pollution control, which contributed to the synergy of pollution and carbon emissions reduction from mobile sources and improvement of air quality.
2024,
42(10):
102-111.
doi: 10.13205/j.hjgc.202410013
Abstract:
Based on analyzing the current situation of VOCs research in various industries, in terms of the railway transportation industry VOCs emission links and characteristics, a whole process control measure was proposed by combining VOCs emission standards, governance technologies and problems in management and control. The research showed that VOCs have only been studied in the railway transportation industry in the last five years, with a focus on treatment techniques. There were many VOCs emission links in the railway industry, of which the ones with a greater environmental impact were the cleaning, overhaul and painting phases of train maintenance. Meanwhile, VOCs concentrations in each category vary with different workplaces. The concentrations of VOCs in the injection pump workshop and the open liquid level of the oil storage tank were in the sequence of aliphatic hydrocarbons>halogenated hydrocarbons>oxygenated compounds>aromatic hydrocarbons, and those in the painting treatment warehouse and the open level of dipping paint were in the sequence of halogenated hydrocarbons>oxygenated compounds>aromatic hydrocarbons>aliphatic hydrocarbons. The VOCs emitted from oils had the highest concentrations of aliphatic hydrocarbons, while the VOCs emitted from paints had the highest concentrations of halogenated hydrocarbons. In addition, it was found that there were few standards and governance techniques suitable for the rail industry. In the course of the full railway coverage survey, some operating sites had outdated treatment facilities, unsealed operating sites and some leaking pipes, and suitable VOCs management technology and monitoring systems had not yet been developed. Furthermore, a construction approach was proposed for the refinement of VOCs throughout the whole process of emission reduction and control for the railway transportation industry. The research results can provide an important basis for the precise reduction of VOCs in China’s railway transportation industry.
Based on analyzing the current situation of VOCs research in various industries, in terms of the railway transportation industry VOCs emission links and characteristics, a whole process control measure was proposed by combining VOCs emission standards, governance technologies and problems in management and control. The research showed that VOCs have only been studied in the railway transportation industry in the last five years, with a focus on treatment techniques. There were many VOCs emission links in the railway industry, of which the ones with a greater environmental impact were the cleaning, overhaul and painting phases of train maintenance. Meanwhile, VOCs concentrations in each category vary with different workplaces. The concentrations of VOCs in the injection pump workshop and the open liquid level of the oil storage tank were in the sequence of aliphatic hydrocarbons>halogenated hydrocarbons>oxygenated compounds>aromatic hydrocarbons, and those in the painting treatment warehouse and the open level of dipping paint were in the sequence of halogenated hydrocarbons>oxygenated compounds>aromatic hydrocarbons>aliphatic hydrocarbons. The VOCs emitted from oils had the highest concentrations of aliphatic hydrocarbons, while the VOCs emitted from paints had the highest concentrations of halogenated hydrocarbons. In addition, it was found that there were few standards and governance techniques suitable for the rail industry. In the course of the full railway coverage survey, some operating sites had outdated treatment facilities, unsealed operating sites and some leaking pipes, and suitable VOCs management technology and monitoring systems had not yet been developed. Furthermore, a construction approach was proposed for the refinement of VOCs throughout the whole process of emission reduction and control for the railway transportation industry. The research results can provide an important basis for the precise reduction of VOCs in China’s railway transportation industry.
2024,
42(10):
112-120.
doi: 10.13205/j.hjgc.202410014
Abstract:
Under the background of "Dual Carbon Goal", the preparation of biochar using biomass as the raw material instead of coal-based carbon for low-temperature denitrification of sintering flue gas in iron and steel industry has become a research hotspot. In this paper, using biomass as raw material, the effects of nitric acid oxidation, Mn doping amount, binder addition and activation conditions on material properties were investigated through single-factor experiments, and Mn-doped porous carbon matrix composite functional materials with the required mechanical strength, high denitrification efficiency and good catalytic stability were prepared. Moreover, the structure-activity relationship between material composition, structure and low-temperature denitrification activity was initially explored through a series of characterization. The results showed that the composite functional material with the best comprehensive properties was obtained by doping the active component Mn with the addition of mixed binder and water vapor activation. The steady-state removal rate of NO at low temperature (120 ℃) was 66.4%, which was about 7 times that of the coal-based activated carbon. The denitrification activity was also significantly higher than that of coal-based activated carbon under simulated wet flue gas conditions. The research results provide a new idea for the low-temperature SCR denitrification of sintering flue gas in iron and steel industry.
Under the background of "Dual Carbon Goal", the preparation of biochar using biomass as the raw material instead of coal-based carbon for low-temperature denitrification of sintering flue gas in iron and steel industry has become a research hotspot. In this paper, using biomass as raw material, the effects of nitric acid oxidation, Mn doping amount, binder addition and activation conditions on material properties were investigated through single-factor experiments, and Mn-doped porous carbon matrix composite functional materials with the required mechanical strength, high denitrification efficiency and good catalytic stability were prepared. Moreover, the structure-activity relationship between material composition, structure and low-temperature denitrification activity was initially explored through a series of characterization. The results showed that the composite functional material with the best comprehensive properties was obtained by doping the active component Mn with the addition of mixed binder and water vapor activation. The steady-state removal rate of NO at low temperature (120 ℃) was 66.4%, which was about 7 times that of the coal-based activated carbon. The denitrification activity was also significantly higher than that of coal-based activated carbon under simulated wet flue gas conditions. The research results provide a new idea for the low-temperature SCR denitrification of sintering flue gas in iron and steel industry.
2024,
42(10):
121-131.
doi: 10.13205/j.hjgc.202410015
Abstract:
The output of fly ash is increasing year by year, resulting in waste of resources and environmental health hazards. With the adjustment of the industrialization structure, the huge storage of fly ash has brought a series of pressures and challenges. At present, the extraction of rare earth elements from fly ash to achieve high value-added recycling has become an important solution to solve the problem of fly ash. In this paper, the utilization status and existing extraction methods of rare earth elements in fly ash are reviewed, and the existing technical processes are systematically summarized and discussed, to provide a reference for the resource utilization of rare earth elements in fly ash. In this paper, it is found that the traditional methods of recovering rare earth elements from fly ash have high recovery rates, but the cost and secondary pollution risk is high. New technologies such as biological methods have lower energy consumption and are environmentally friendly, which are more promising than traditional methods, but the technology is immature, and there are problems such as long cycles, low efficiency, and difficult separation of the products. Therefore, the future development direction should focus on the cost reduction and efficiency increase of traditional methods and the process optimization of new methods. This paper can provide reference for fly ash resource utilization, to form an environmentally friendly, economical, and efficient fly ash recovery strategy, practice the reduction, reuse and resource utilization of circular economy, and help the sustainable development of China’s mining industry.
The output of fly ash is increasing year by year, resulting in waste of resources and environmental health hazards. With the adjustment of the industrialization structure, the huge storage of fly ash has brought a series of pressures and challenges. At present, the extraction of rare earth elements from fly ash to achieve high value-added recycling has become an important solution to solve the problem of fly ash. In this paper, the utilization status and existing extraction methods of rare earth elements in fly ash are reviewed, and the existing technical processes are systematically summarized and discussed, to provide a reference for the resource utilization of rare earth elements in fly ash. In this paper, it is found that the traditional methods of recovering rare earth elements from fly ash have high recovery rates, but the cost and secondary pollution risk is high. New technologies such as biological methods have lower energy consumption and are environmentally friendly, which are more promising than traditional methods, but the technology is immature, and there are problems such as long cycles, low efficiency, and difficult separation of the products. Therefore, the future development direction should focus on the cost reduction and efficiency increase of traditional methods and the process optimization of new methods. This paper can provide reference for fly ash resource utilization, to form an environmentally friendly, economical, and efficient fly ash recovery strategy, practice the reduction, reuse and resource utilization of circular economy, and help the sustainable development of China’s mining industry.
2024,
42(10):
132-139.
doi: 10.13205/j.hjgc.202410016
Abstract:
As an inevitable strategic choice for aviation carbon neutrality, the application of sustainable aviation fuel (SAF) can significantly reduce the carbon emissions of the aviation industry. Bibliometric analysis combined with the S-curve technique and visualization tools (VOSviewer) were applied, to quantitatively analyze 2440 articles related to SAF research in the Web of Science from 2001 to 2022. The development trend of key technologies for SAF based on the incoPat Global Patent Database was also conducted. Biblio-metric results revealed that the number of articles on SAF had increased from 8 in 2001 to 388 in 2022, and it intuitively showed that SAF technology has great development potential in the next 20 years by constructing the S-curve of the published volume. In the global competition for sustainable aviation fuel technology, China ranks second in terms of publication volume in the world after the United States, both of them are core countries in the international cooperation network. The co-occurrence and evolution path of keywords suggests that "ethanol", "microalgae", "cellulose", "hydrodeoxygenation", "Fischer-Tropsch synthesis" and "life cycle assessment" have become the current research hotspots. Patent data analysis demonstrates that the two key technologies, "hydrodeoxygenation" and "Fischer-Tropsch synthesis", have become a relatively mature. This bibliometric conclusion can provide support for China to develop its own sustainable aviation fuel technology and industry based on its own national situations.
As an inevitable strategic choice for aviation carbon neutrality, the application of sustainable aviation fuel (SAF) can significantly reduce the carbon emissions of the aviation industry. Bibliometric analysis combined with the S-curve technique and visualization tools (VOSviewer) were applied, to quantitatively analyze 2440 articles related to SAF research in the Web of Science from 2001 to 2022. The development trend of key technologies for SAF based on the incoPat Global Patent Database was also conducted. Biblio-metric results revealed that the number of articles on SAF had increased from 8 in 2001 to 388 in 2022, and it intuitively showed that SAF technology has great development potential in the next 20 years by constructing the S-curve of the published volume. In the global competition for sustainable aviation fuel technology, China ranks second in terms of publication volume in the world after the United States, both of them are core countries in the international cooperation network. The co-occurrence and evolution path of keywords suggests that "ethanol", "microalgae", "cellulose", "hydrodeoxygenation", "Fischer-Tropsch synthesis" and "life cycle assessment" have become the current research hotspots. Patent data analysis demonstrates that the two key technologies, "hydrodeoxygenation" and "Fischer-Tropsch synthesis", have become a relatively mature. This bibliometric conclusion can provide support for China to develop its own sustainable aviation fuel technology and industry based on its own national situations.
2024,
42(10):
140-146.
doi: 10.13205/j.hjgc.202410017
Abstract:
With the implementation of China’s garbage classification policy and of the Dual Carbon Goal, the kitchen waste treatment industry is in a rapid development stage. Compared with traditional processes such as landfill and incineration, anaerobic fermentation of kitchen waste has the advantages of high resource utilization and environmental friendliness; the diversity of anaerobic fermentation products gives it a wide range of development and application potential. This article summarizes the mechanism and development status of anaerobic fermentation of kitchen waste, and focuses on analyzing the research and engineering application of producing biogas and acid as the main products. At the same time, the current problems and future development directions in the field of anaerobic fermentation of kitchen waste are discussed. The aim is to provide support for the selection of suitable anaerobic fermentation treatment methods for kitchen waste in different regions, promote the efficient and low-cost development of kitchen waste recycling technology, and strengthen the effective disposal of kitchen waste and the multi-scenario application of resource products.
With the implementation of China’s garbage classification policy and of the Dual Carbon Goal, the kitchen waste treatment industry is in a rapid development stage. Compared with traditional processes such as landfill and incineration, anaerobic fermentation of kitchen waste has the advantages of high resource utilization and environmental friendliness; the diversity of anaerobic fermentation products gives it a wide range of development and application potential. This article summarizes the mechanism and development status of anaerobic fermentation of kitchen waste, and focuses on analyzing the research and engineering application of producing biogas and acid as the main products. At the same time, the current problems and future development directions in the field of anaerobic fermentation of kitchen waste are discussed. The aim is to provide support for the selection of suitable anaerobic fermentation treatment methods for kitchen waste in different regions, promote the efficient and low-cost development of kitchen waste recycling technology, and strengthen the effective disposal of kitchen waste and the multi-scenario application of resource products.
2024,
42(10):
147-154.
doi: 10.13205/j.hjgc.202410018
Abstract:
To investigate the characteristics of earthworm enrichment of heavy metals in the process of rice husk charcoal composting sludge, 0, 2%, 4%, 6%, and 8% (mass fraction) rice husk charcoal was added to the sludge to undergo earthworm composting respectively. Through the internal correlation analysis of heavy metals concentrations in sludge, earthworm epidermis, intestine, and whole body, the pathways of earthworm absorption of heavy metals in sludge were explored. The results showed that after adding rice husk charcoal to the earthworm sludge composting system, the pH and TK of the composted sludge increased, while the EC, TOC, TP, and available heavy metals contents of the composted sludge decreased; the addition of rice husk charcoal increased the heavy metal content in the whole bodies, epidermis, and intestines of earthworms, thereby reducing the available heavy metals contents in sludge; the addition of rice husk charcoal promoted the trend of earthworm epidermis absorbing heavy metals. The distribution coefficients of Cr, Cu, and Zn increased with the increase of rice husk charcoal dosage, while the distribution coefficients of Pb decreased with the increase of this dosage; the addition of rice husk charcoal affects the overall heavy metals absorption capacity of earthworms by changing pH and EC of sludge, affected the heavy metals absorption capacity of earthworm epidermis by changing the pH, TOC, TN, and TP of sludge, and affected the heavy metals absorption capacity of earthworm intestines by changing TN and TP of sludge. This study can provide theoretical support for the regulation of heavy metals in earthworm compost sludge by biochar and the resource utilization of sludge.
To investigate the characteristics of earthworm enrichment of heavy metals in the process of rice husk charcoal composting sludge, 0, 2%, 4%, 6%, and 8% (mass fraction) rice husk charcoal was added to the sludge to undergo earthworm composting respectively. Through the internal correlation analysis of heavy metals concentrations in sludge, earthworm epidermis, intestine, and whole body, the pathways of earthworm absorption of heavy metals in sludge were explored. The results showed that after adding rice husk charcoal to the earthworm sludge composting system, the pH and TK of the composted sludge increased, while the EC, TOC, TP, and available heavy metals contents of the composted sludge decreased; the addition of rice husk charcoal increased the heavy metal content in the whole bodies, epidermis, and intestines of earthworms, thereby reducing the available heavy metals contents in sludge; the addition of rice husk charcoal promoted the trend of earthworm epidermis absorbing heavy metals. The distribution coefficients of Cr, Cu, and Zn increased with the increase of rice husk charcoal dosage, while the distribution coefficients of Pb decreased with the increase of this dosage; the addition of rice husk charcoal affects the overall heavy metals absorption capacity of earthworms by changing pH and EC of sludge, affected the heavy metals absorption capacity of earthworm epidermis by changing the pH, TOC, TN, and TP of sludge, and affected the heavy metals absorption capacity of earthworm intestines by changing TN and TP of sludge. This study can provide theoretical support for the regulation of heavy metals in earthworm compost sludge by biochar and the resource utilization of sludge.
2024,
42(10):
155-164.
doi: 10.13205/j.hjgc.202410019
Abstract:
Heavymetal contamination in farmland is closely related to food safety and human health. This study investigated the heavy metal pollution in farmland soil near the Wushikeng Iron Mine in Guixi, Jiangxi Province. We collected 52 soil samples from the abandoned mining pits, tailings ponds, and downstream farmlands. We used the geo-accumulation index method and the potential ecological risk assessment method to evaluate the pollution characteristics of heavy metals in the soil. Additionally, the absolute principal component-multiple linear regression model (APCS-MLR) and positive matrix factorization model (PMF) were used to determine the sources of heavy metals detected in the soil. The study results showed that the contents of Cu, Cd, and As in the downstream farmland soil exceeded the screening value of the Soil Environmental Quality-Agricultural Land Soil Pollution Risk Control Standard (Trial) of China. The geo-accumulation index evaluation revealed that Cd was in moderately pollution level, Cu, Ni, and Zn were in slightly pollution level, and As, Hg, and Pb were in pollution-free level. Moreover, the potential ecological risk assessment results indicated that Cd (133.36) posed a strong ecological risk, Hg (54.18) posed a moderate ecological risk, and the other heavy metal elements posed a mild ecological risk. The average comprehensive ecological risk index of the study area was 226.59, indicating a strong potential ecological risk. Both the APCS-MLR and PMF models identified the sources of heavy metals in the soil. The results showed that Pb is mainly from natural sources, Cd and Cu are mainly affected by abandoned iron ore, Zn and Ni are affected by both natural and abandoned iron ore, As is mainly from farms, and Hg is mainly affected by fossil fuel combustion.
Heavymetal contamination in farmland is closely related to food safety and human health. This study investigated the heavy metal pollution in farmland soil near the Wushikeng Iron Mine in Guixi, Jiangxi Province. We collected 52 soil samples from the abandoned mining pits, tailings ponds, and downstream farmlands. We used the geo-accumulation index method and the potential ecological risk assessment method to evaluate the pollution characteristics of heavy metals in the soil. Additionally, the absolute principal component-multiple linear regression model (APCS-MLR) and positive matrix factorization model (PMF) were used to determine the sources of heavy metals detected in the soil. The study results showed that the contents of Cu, Cd, and As in the downstream farmland soil exceeded the screening value of the Soil Environmental Quality-Agricultural Land Soil Pollution Risk Control Standard (Trial) of China. The geo-accumulation index evaluation revealed that Cd was in moderately pollution level, Cu, Ni, and Zn were in slightly pollution level, and As, Hg, and Pb were in pollution-free level. Moreover, the potential ecological risk assessment results indicated that Cd (133.36) posed a strong ecological risk, Hg (54.18) posed a moderate ecological risk, and the other heavy metal elements posed a mild ecological risk. The average comprehensive ecological risk index of the study area was 226.59, indicating a strong potential ecological risk. Both the APCS-MLR and PMF models identified the sources of heavy metals in the soil. The results showed that Pb is mainly from natural sources, Cd and Cu are mainly affected by abandoned iron ore, Zn and Ni are affected by both natural and abandoned iron ore, As is mainly from farms, and Hg is mainly affected by fossil fuel combustion.
2024,
42(10):
165-176.
doi: 10.13205/j.hjgc.202410020
Abstract:
To determine the combined effect of rice straw biochar and Bacillus on the transformation of heavy metal speciation and the mechanisms affecting microbial communities in Cu-Cd contaminated soil, the contents of different speciation of Cu and Cd in soil, soil chemical properties and enzyme activities were compared and analyzed through soil culture experiments. The structure composition and diversity response patterns of soil microbial communities were investigated by high-throughput sequencing technology. The results indicated that after biochar and microbial (BC+M) treatment, the acid-extractable Cu and Cd contents decreased significantly, and the contents decreased by 27.35% and 27.48%, respectively. BC+M significantly enhanced soil pH value, and enhanced soil available phosphorus, available potassium and catalase activity by 114.16%, 462.76% and 113.79%, respectively. Acid-extracted Cu and Cd were negatively correlated with pH, alkali-hydrolyzed nitrogen (AN), available phosphorus (AP), available potassium (AK), cation exchange capacity (CEC) and organic matter (SOM), but acid-extracted Cu was significantly negatively correlated with AK and AP (P<0.05), and acid-extracted Cd was significantly negatively correlated with AK and pH (P<0.05). The BC+M treatment significantly diversified the soil microbial communities, mainly increasing the abundance of dominant bacterial groups such as Chloroflexi, Actinobacteriota, Firmicutes, Acidobacteriota and Bacteroidota, which are known for strong resistance to heavy metals. Compared to fungal communities, bacterial communities respond more intensely to changes in soil environmental factors, especially Proteobacteria, Chloroflexi, Firmicutes, Acidobacteriota and Bacteroidota. Rice straw biochar and Bacillus primarily affect soil pH, AP, AK and the structure of the bacterial community, thereby facilitating the transformation of acid-extractable forms of Cu and Cd into other potentially less harmful states. This provides a theoretical reference for the microbial processes in soil heavy metal pollution remediation.
To determine the combined effect of rice straw biochar and Bacillus on the transformation of heavy metal speciation and the mechanisms affecting microbial communities in Cu-Cd contaminated soil, the contents of different speciation of Cu and Cd in soil, soil chemical properties and enzyme activities were compared and analyzed through soil culture experiments. The structure composition and diversity response patterns of soil microbial communities were investigated by high-throughput sequencing technology. The results indicated that after biochar and microbial (BC+M) treatment, the acid-extractable Cu and Cd contents decreased significantly, and the contents decreased by 27.35% and 27.48%, respectively. BC+M significantly enhanced soil pH value, and enhanced soil available phosphorus, available potassium and catalase activity by 114.16%, 462.76% and 113.79%, respectively. Acid-extracted Cu and Cd were negatively correlated with pH, alkali-hydrolyzed nitrogen (AN), available phosphorus (AP), available potassium (AK), cation exchange capacity (CEC) and organic matter (SOM), but acid-extracted Cu was significantly negatively correlated with AK and AP (P<0.05), and acid-extracted Cd was significantly negatively correlated with AK and pH (P<0.05). The BC+M treatment significantly diversified the soil microbial communities, mainly increasing the abundance of dominant bacterial groups such as Chloroflexi, Actinobacteriota, Firmicutes, Acidobacteriota and Bacteroidota, which are known for strong resistance to heavy metals. Compared to fungal communities, bacterial communities respond more intensely to changes in soil environmental factors, especially Proteobacteria, Chloroflexi, Firmicutes, Acidobacteriota and Bacteroidota. Rice straw biochar and Bacillus primarily affect soil pH, AP, AK and the structure of the bacterial community, thereby facilitating the transformation of acid-extractable forms of Cu and Cd into other potentially less harmful states. This provides a theoretical reference for the microbial processes in soil heavy metal pollution remediation.
2024,
42(10):
177-187.
doi: 10.13205/j.hjgc.202410021
Abstract:
To assess the degree of heavy metals pollution and human health risk in undisturbed soil of a simple domestic waste landfill, a small-scale domestic waste landfill in Zhejiang Province was taken as an example, and 54 soil samples were collected from 18 soil sites in the landfill. The contents of Cu, Pb, Cd, Hg, As, and Zn in the soil samples were analyzed. Pollution load index (PLI), ground accumulation index (Igeo), and potential ecological risk index (RI) were comprehensively used to investigate the characteristics of heavy metals pollution. The health risk assessment of heavy metals in adults was carried out by the USEPA health risk assessment model. The results showed that the overall pollution degree of 6 heavy metals in 18 soil sites was mainly in a non-polluting and light pollution level, and the main indicators of pollution accumulation and potential risk were Cd, As, Cu, and Hg. However, attention should be paid to the middle and lower soil layers, because they are more seriously polluted than the surface layer, and a few have high and extremely high ecological risks. Oral intake is the main exposure pathway for carcinogenic risk. 95% of the values of As and Cd showed significant carcinogenic risk; the noncarcinogenic index and total hazard index of adults under the three exposure routes were less than 1, so there was no risk. The research results can provide data reference for the follow-up treatment of simple domestic waste landfills. Whether the site is closed for control, excavation screening, utilization, or relocation, it can provide data support for the ecological restoration of soil pollution at the original site, and provide a scientific basis for risk control and restoration.
To assess the degree of heavy metals pollution and human health risk in undisturbed soil of a simple domestic waste landfill, a small-scale domestic waste landfill in Zhejiang Province was taken as an example, and 54 soil samples were collected from 18 soil sites in the landfill. The contents of Cu, Pb, Cd, Hg, As, and Zn in the soil samples were analyzed. Pollution load index (PLI), ground accumulation index (Igeo), and potential ecological risk index (RI) were comprehensively used to investigate the characteristics of heavy metals pollution. The health risk assessment of heavy metals in adults was carried out by the USEPA health risk assessment model. The results showed that the overall pollution degree of 6 heavy metals in 18 soil sites was mainly in a non-polluting and light pollution level, and the main indicators of pollution accumulation and potential risk were Cd, As, Cu, and Hg. However, attention should be paid to the middle and lower soil layers, because they are more seriously polluted than the surface layer, and a few have high and extremely high ecological risks. Oral intake is the main exposure pathway for carcinogenic risk. 95% of the values of As and Cd showed significant carcinogenic risk; the noncarcinogenic index and total hazard index of adults under the three exposure routes were less than 1, so there was no risk. The research results can provide data reference for the follow-up treatment of simple domestic waste landfills. Whether the site is closed for control, excavation screening, utilization, or relocation, it can provide data support for the ecological restoration of soil pollution at the original site, and provide a scientific basis for risk control and restoration.
2024,
42(10):
188-200.
doi: 10.13205/j.hjgc.202410022
Abstract:
Analysing the spatiotemporal heterogeneity of China’s energy carbon emission efficiency is one of the keys to researching and formulating regional energy carbon emission efficiency improvement strategies and accelerating the realization of the Double Carbon goal. This study proposed a framework for analyzing spatiotemporal heterogeneity of energy carbon emissions based on the combination of the SBM-DEA (slack-based measure-data envelopment analysis) and the spatiotemporal weighted regression (STWR) model. Firstly, the energy carbon emission efficiency index (ECEI) was calculated based on SBM-DEA model. Then, the spatiotemporal non-stationary relationships between the efficiency index and its main driving forces from 2012 to 2019, i.e., the degree of opening to the outside world, the level of urbanization, the investment in science and technology, and the proportion of coal consumption were built by using STWR. Furthermore, based on the dynamic time warping algorithm (dynamic time warping, DTW), the similarity between the time series of different coefficients corresponding to each independent variable, which was generated by the STWR model, was calculated. The K-Medoids were employed to cluster based on the similarity with using the Elbow method to determine the optimal cluster number of K. The results show that China’s energy carbon emissions are generally increasing, but the ECEI has not improved. 1) Among them, the degree of openness to the ECEI presents a ladder distribution from the western to the eastern, and the overall positive impact intensity is western regions>central regions>eastern regions. 2) Most of the impact of urbanization level is positive, the degree increases first and then decreases, and reaches the maximum in 2015. The urbanization level in southern China has a U-shaped relationship with energy and carbon emission efficiency, and the degree of negative impact first increases and then decreases. 3) The investment in science and technology is mainly positively correlated with the efficiency of energy and carbon emissions. The coastal areas are relatively stable, and the positive impact of Hubei and Hunan is gradually increasing, while the three northeastern provinces (Heilongjiang, Jilin, and Liaoning) and Sichuan are negatively correlated. 4) From 2013 to 2017, the proportion of coal consumption in each region had a negative impact on energy carbon emission efficiency, concentrated in the central region and showed an extension trend, and its influence gradually was weakened. The proportion of coal consumption in Hebei, Henan, and Shaanxi has a large negative impact on energy carbon emission efficiency, showing a W shape. The proposed analysis framework can conduct a multi-dimensional evaluation of environmental impact, resource consumption, and social value, and measure China’s carbon emission efficiency more scientifically and reasonably. It is the first time to introduce the STWR model, which can be used to explore the sub-stationarity relationship between the energy carbon emission efficiency value and the main driving factors and its change over time. Clustering of time-series coefficients can help identify the spatiotemporal pattern of carbon emission efficiency and support decision-making to coordinate regional energy consumption and carbon dioxide emissions dynamically and rationally.
Analysing the spatiotemporal heterogeneity of China’s energy carbon emission efficiency is one of the keys to researching and formulating regional energy carbon emission efficiency improvement strategies and accelerating the realization of the Double Carbon goal. This study proposed a framework for analyzing spatiotemporal heterogeneity of energy carbon emissions based on the combination of the SBM-DEA (slack-based measure-data envelopment analysis) and the spatiotemporal weighted regression (STWR) model. Firstly, the energy carbon emission efficiency index (ECEI) was calculated based on SBM-DEA model. Then, the spatiotemporal non-stationary relationships between the efficiency index and its main driving forces from 2012 to 2019, i.e., the degree of opening to the outside world, the level of urbanization, the investment in science and technology, and the proportion of coal consumption were built by using STWR. Furthermore, based on the dynamic time warping algorithm (dynamic time warping, DTW), the similarity between the time series of different coefficients corresponding to each independent variable, which was generated by the STWR model, was calculated. The K-Medoids were employed to cluster based on the similarity with using the Elbow method to determine the optimal cluster number of K. The results show that China’s energy carbon emissions are generally increasing, but the ECEI has not improved. 1) Among them, the degree of openness to the ECEI presents a ladder distribution from the western to the eastern, and the overall positive impact intensity is western regions>central regions>eastern regions. 2) Most of the impact of urbanization level is positive, the degree increases first and then decreases, and reaches the maximum in 2015. The urbanization level in southern China has a U-shaped relationship with energy and carbon emission efficiency, and the degree of negative impact first increases and then decreases. 3) The investment in science and technology is mainly positively correlated with the efficiency of energy and carbon emissions. The coastal areas are relatively stable, and the positive impact of Hubei and Hunan is gradually increasing, while the three northeastern provinces (Heilongjiang, Jilin, and Liaoning) and Sichuan are negatively correlated. 4) From 2013 to 2017, the proportion of coal consumption in each region had a negative impact on energy carbon emission efficiency, concentrated in the central region and showed an extension trend, and its influence gradually was weakened. The proportion of coal consumption in Hebei, Henan, and Shaanxi has a large negative impact on energy carbon emission efficiency, showing a W shape. The proposed analysis framework can conduct a multi-dimensional evaluation of environmental impact, resource consumption, and social value, and measure China’s carbon emission efficiency more scientifically and reasonably. It is the first time to introduce the STWR model, which can be used to explore the sub-stationarity relationship between the energy carbon emission efficiency value and the main driving factors and its change over time. Clustering of time-series coefficients can help identify the spatiotemporal pattern of carbon emission efficiency and support decision-making to coordinate regional energy consumption and carbon dioxide emissions dynamically and rationally.
2024,
42(10):
201-208.
doi: 10.13205/j.hjgc.202410023
Abstract:
Compared with the traditional organic amine absorber, 30% MEA, the biphasic solvent has more significant development advantages in reducing the energy consumption of CO2 capture. In this paper, monoethanolamine (MEA), hydroxyethyl ethylenediamine (AEEA), diethylenetriamine (DETA) and triethylenetetramine (TETA) with different amino structures were selected as the main absorbers and compounded with the phase-splitting agent diethylethanolamine (DEEA) and water in the ratio of 1∶2∶1, to construct four different biphasic absorption systems. Through a comparative study of their phase splitting performance, absorption-desorption performance, and viscosity characteristics, DEEA+DETA was selected as the most promising biphasic absorption system, and its regeneration energy consumption and cycle stability were investigated in detail. The results showed that the biphasic solvent of DEEA+DETA, with a wide range of split-phase loading and moderate viscosity, has an absorption load of up to 3.26 mol/L, a cyclic capacity of 2.52 mol/L, and a low regeneration energy consumption of 2.55 GJ/t CO2, 32.9% lower than that of 30% MEA. It still maintained high absorption-desorption performance and good cyclic stability after 10 cycles.
Compared with the traditional organic amine absorber, 30% MEA, the biphasic solvent has more significant development advantages in reducing the energy consumption of CO2 capture. In this paper, monoethanolamine (MEA), hydroxyethyl ethylenediamine (AEEA), diethylenetriamine (DETA) and triethylenetetramine (TETA) with different amino structures were selected as the main absorbers and compounded with the phase-splitting agent diethylethanolamine (DEEA) and water in the ratio of 1∶2∶1, to construct four different biphasic absorption systems. Through a comparative study of their phase splitting performance, absorption-desorption performance, and viscosity characteristics, DEEA+DETA was selected as the most promising biphasic absorption system, and its regeneration energy consumption and cycle stability were investigated in detail. The results showed that the biphasic solvent of DEEA+DETA, with a wide range of split-phase loading and moderate viscosity, has an absorption load of up to 3.26 mol/L, a cyclic capacity of 2.52 mol/L, and a low regeneration energy consumption of 2.55 GJ/t CO2, 32.9% lower than that of 30% MEA. It still maintained high absorption-desorption performance and good cyclic stability after 10 cycles.
2024,
42(10):
209-217.
doi: 10.13205/j.hjgc.202410024
Abstract:
Achieving carbon peak and carbon neutrality is a major strategy made by China, which puts forward an urgent need for accurate estimation of carbon sources and sinks. More and more concerns are focused on top-down approaches, which estimate the CO2 exchanges of the Earth’s surface with atmosphere to ensure the objectivity, rationality and accuracy of carbon data. Although the theory of top-down inversion is rigorous, the inversion of carbon source and sink from atmospheric concentration variations turns out to be a challenging scientific problem for a long time. Based on space-borne and ground-based measurements, previous atmospheric inversions have improved the understanding of global terrestrial and ocean carbon fluxes. However, there are still significant uncertainties in the estimation of carbon fluxes at urban and regional scales. On the one hand, at the regional scale, the atmospheric inversion of China’s terrestrial biosphere carbon sources and sinks are used as a reference. Most of China’s carbon sink inversion research adopts global atmospheric transport models to assimilate natural fluxes, which quantifies the biosphere carbon budget with a relatively coarse spatial resolution and long timescale from a weekly or monthly perspective. The limitations in observations and model errors lead to great uncertainty in the inversions, and there is considerable controversy among previous top-down results. Based on the mesoscale atmospheric transport models, several regional carbon assimilation schemes were found to help improve the spatiotemporal resolution of carbon fluxes estimation and reduce the bias in atmospheric inversion. At the urban scale, cities are the main sources of CO2 anthropogenic emissions. The bottom-up approach, taking inventory as an example, has some disadvantages on account of the uncertainties and temporal hysteresis in statistics of energy consumption data. Through carbon assimilation techniques, carbon emissions can be estimated more objectively and timely. Moreover, implementing cross-validation of top-down and bottom-up estimates is beneficial to the credibility of carbon data. In general, great progress has been made in carbon data assimilation at the urban and regional scales during recent decades. In the future, it is urgent to reduce the impact of model and observation uncertainties, to carry out accurate inversions from terrestrial and anthropogenic aspects, which will form an important scientific and practical basis for investigating the regional carbon cycle.
Achieving carbon peak and carbon neutrality is a major strategy made by China, which puts forward an urgent need for accurate estimation of carbon sources and sinks. More and more concerns are focused on top-down approaches, which estimate the CO2 exchanges of the Earth’s surface with atmosphere to ensure the objectivity, rationality and accuracy of carbon data. Although the theory of top-down inversion is rigorous, the inversion of carbon source and sink from atmospheric concentration variations turns out to be a challenging scientific problem for a long time. Based on space-borne and ground-based measurements, previous atmospheric inversions have improved the understanding of global terrestrial and ocean carbon fluxes. However, there are still significant uncertainties in the estimation of carbon fluxes at urban and regional scales. On the one hand, at the regional scale, the atmospheric inversion of China’s terrestrial biosphere carbon sources and sinks are used as a reference. Most of China’s carbon sink inversion research adopts global atmospheric transport models to assimilate natural fluxes, which quantifies the biosphere carbon budget with a relatively coarse spatial resolution and long timescale from a weekly or monthly perspective. The limitations in observations and model errors lead to great uncertainty in the inversions, and there is considerable controversy among previous top-down results. Based on the mesoscale atmospheric transport models, several regional carbon assimilation schemes were found to help improve the spatiotemporal resolution of carbon fluxes estimation and reduce the bias in atmospheric inversion. At the urban scale, cities are the main sources of CO2 anthropogenic emissions. The bottom-up approach, taking inventory as an example, has some disadvantages on account of the uncertainties and temporal hysteresis in statistics of energy consumption data. Through carbon assimilation techniques, carbon emissions can be estimated more objectively and timely. Moreover, implementing cross-validation of top-down and bottom-up estimates is beneficial to the credibility of carbon data. In general, great progress has been made in carbon data assimilation at the urban and regional scales during recent decades. In the future, it is urgent to reduce the impact of model and observation uncertainties, to carry out accurate inversions from terrestrial and anthropogenic aspects, which will form an important scientific and practical basis for investigating the regional carbon cycle.
