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2022 Vol. 40, No. 12
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2022, 40(12): 9-16.
doi: 10.13205/j.hjgc.202212002
Abstract:
China and the United States have large wastewater treatment and high carbon emission scale. The carbon emission from sludge treatment and disposal is an important part of the total carbon emission of sewage treatment plants. A reasonable sludge management strategy is the key to future carbon emission reduction of sewage treatment plants. In this paper, the sludge treatment facilities and paths of six typical wastewater treatment plants in China and the United States were investigated on-site, and the performance characteristics of energy recovery and carbon emission of different typical sludge treatment processes in China and the United States were analyzed. The results showed that, without considering carbon offset, among the six wastewater treatment plants in China and the US, the carbon emission of East China A (mesophilic anaerobic digestion+dewatering+landfill/land use), East China B (dewatering+landfill/incineration), East China C (dewatering+incineration), Hyperion (thermophilic anaerobic digestion+dewatering+agricultural end-use), OCSD (mesophilic anaerobic digestion+dewatering+agriculture end-use) and Blue plains (thermo hydrolysis+mesophilic anaerobic digestion+dewatering+agricultural end-use) were 1410, 1881, 1914, 471, 402, 405 kg CO2/t DS, respectively. Considering the carbon offset effect caused by energy recovery and resource utilization, the net carbon emission from sludge treatment and disposal in the six WWTPs were 984, 1681, 1941, -183, -240, -315 kg CO2/t DS, respectively. The carbon emission offset efficiency of six WWTPs in China and the United States was 30.2%, 10.6%, 0%, 138.9%, 159.7% and 177.9%, respectively. Sludge anaerobic digestion and land utilization of its product were the keys to carbon emission reduction, and increasing the organic matter content of sludge could enhance the carbon offset effect. The research results could provide basis and reference for the low-carbon transformation of WWTPs in China and the harmless, reduced and low-carbon treatment of sludge.
China and the United States have large wastewater treatment and high carbon emission scale. The carbon emission from sludge treatment and disposal is an important part of the total carbon emission of sewage treatment plants. A reasonable sludge management strategy is the key to future carbon emission reduction of sewage treatment plants. In this paper, the sludge treatment facilities and paths of six typical wastewater treatment plants in China and the United States were investigated on-site, and the performance characteristics of energy recovery and carbon emission of different typical sludge treatment processes in China and the United States were analyzed. The results showed that, without considering carbon offset, among the six wastewater treatment plants in China and the US, the carbon emission of East China A (mesophilic anaerobic digestion+dewatering+landfill/land use), East China B (dewatering+landfill/incineration), East China C (dewatering+incineration), Hyperion (thermophilic anaerobic digestion+dewatering+agricultural end-use), OCSD (mesophilic anaerobic digestion+dewatering+agriculture end-use) and Blue plains (thermo hydrolysis+mesophilic anaerobic digestion+dewatering+agricultural end-use) were 1410, 1881, 1914, 471, 402, 405 kg CO2/t DS, respectively. Considering the carbon offset effect caused by energy recovery and resource utilization, the net carbon emission from sludge treatment and disposal in the six WWTPs were 984, 1681, 1941, -183, -240, -315 kg CO2/t DS, respectively. The carbon emission offset efficiency of six WWTPs in China and the United States was 30.2%, 10.6%, 0%, 138.9%, 159.7% and 177.9%, respectively. Sludge anaerobic digestion and land utilization of its product were the keys to carbon emission reduction, and increasing the organic matter content of sludge could enhance the carbon offset effect. The research results could provide basis and reference for the low-carbon transformation of WWTPs in China and the harmless, reduced and low-carbon treatment of sludge.
2022, 40(12): 17-21,60.
doi: 10.13205/j.hjgc.202212003
Abstract:
Landfill is one of the main anthropogenic emission sources of greenhouse gases. Due to historical reasons, there are a large number of expired landfills and informal storage yards in China facing a severe problem of waste stock that needs to repair urgently. Aerobic remediation technology has been widely used because it can effectively accelerate waste stabilization, but its carbon emission characteristics in the remediation process are still not clear. Taking a large-scale landfill as the object, this paper investigated the change characteristics of landfill organic waste and secondary pollutants under different repairing states, revealed its stabilization process under aerobic repair, and calculated the effect of methane emission reduction in this process. The results showed that under the aeration and water injection of 322.34 m3/min and 25.65 m3/d respectively, by intermittent gas injection method (opening for 3 hours and stopping for 3 hours, running for 9 hours per day), the content of organic matter in garbage decreased from 47.66% to 17.86%; the proportion of methane in landfill gas decreased from 0.02%~46.48% to 4.23%, reaching the requirement that the methane concentration at the outlet of air duct was less than 5%; the concentrations of COD, ammonia nitrogen and total nitrogen in leachate decreased to 800.8 mg/L, 680.9 mg/L and 897.8 mg/L respectively; during the restoration process, the actual methane emission of the landfill was reduced from 24.57 tons to 2.47 tons, cut by 22.10 tons. At the same time, due to the acceleration of the stabilization of the landfill, its methane emission potential was reduced by 1.75 kg/t waste. In conclusion, aerobic remediation could provide important support for methane emission reduction in landfill sites.
Landfill is one of the main anthropogenic emission sources of greenhouse gases. Due to historical reasons, there are a large number of expired landfills and informal storage yards in China facing a severe problem of waste stock that needs to repair urgently. Aerobic remediation technology has been widely used because it can effectively accelerate waste stabilization, but its carbon emission characteristics in the remediation process are still not clear. Taking a large-scale landfill as the object, this paper investigated the change characteristics of landfill organic waste and secondary pollutants under different repairing states, revealed its stabilization process under aerobic repair, and calculated the effect of methane emission reduction in this process. The results showed that under the aeration and water injection of 322.34 m3/min and 25.65 m3/d respectively, by intermittent gas injection method (opening for 3 hours and stopping for 3 hours, running for 9 hours per day), the content of organic matter in garbage decreased from 47.66% to 17.86%; the proportion of methane in landfill gas decreased from 0.02%~46.48% to 4.23%, reaching the requirement that the methane concentration at the outlet of air duct was less than 5%; the concentrations of COD, ammonia nitrogen and total nitrogen in leachate decreased to 800.8 mg/L, 680.9 mg/L and 897.8 mg/L respectively; during the restoration process, the actual methane emission of the landfill was reduced from 24.57 tons to 2.47 tons, cut by 22.10 tons. At the same time, due to the acceleration of the stabilization of the landfill, its methane emission potential was reduced by 1.75 kg/t waste. In conclusion, aerobic remediation could provide important support for methane emission reduction in landfill sites.
2022, 40(12): 22-28.
doi: 10.13205/j.hjgc.202212004
Abstract:
On May 1st, 2020, Beijing officially implemented the Beijing Municipal Household Waste Management Regulations. In order to understand the changes in the characteristics of kitchen waste after garbage classification and domestic waste before classification in Beijing, the garbage in the kitchen waste garbage bins in the garbage classification collection points of residential areas was sampled and analyzed, and then compared with the domestic garbage mix collected and transported in Beijing before classification. The results showed that after Beijing implemented garbage classification, the proportions of kitchen waste components in kitchen waste bins gradually increased. After one year of implementation, the proportion of kitchen waste components reached 99%. The moisture content and bulk density of kitchen waste increased significantly, compared with that before classification, and the combustible points and calorific value were significantly reduced, so it was not suitable for incineration treatment; pH and C/N showed a downward trend, conductivity showed a tiny growing trend, and the contents of organic matter, total nitrogen (in terms of nitrogen element), total phosphorus (in terms of P2O5) and total potassium (in terms of K2O) increased, and the potential for waste resource utilization also increased. Among the seven kinds of heavy (metalloid) metals with greater harm, such as Cd, Pb, Cr, Hg, As, Cu and Zn, except for As, the content of the remaining metal elements showed a downward trend; among the metal elements such as Na, Ca, Mg, Fe, and Mn, the content of the remaining elements, except Na, showed a downward trend. Therefore, the metal content in kitchen waste could be effectively controlled through the garbage sorting, so that the seed germination index could be increased, the biological toxic effect on plants reduced, and the environmental risk reduced. This study can provide a reference and basis for the planning of waste resource utilization and treatment facilities in Beijing.
On May 1st, 2020, Beijing officially implemented the Beijing Municipal Household Waste Management Regulations. In order to understand the changes in the characteristics of kitchen waste after garbage classification and domestic waste before classification in Beijing, the garbage in the kitchen waste garbage bins in the garbage classification collection points of residential areas was sampled and analyzed, and then compared with the domestic garbage mix collected and transported in Beijing before classification. The results showed that after Beijing implemented garbage classification, the proportions of kitchen waste components in kitchen waste bins gradually increased. After one year of implementation, the proportion of kitchen waste components reached 99%. The moisture content and bulk density of kitchen waste increased significantly, compared with that before classification, and the combustible points and calorific value were significantly reduced, so it was not suitable for incineration treatment; pH and C/N showed a downward trend, conductivity showed a tiny growing trend, and the contents of organic matter, total nitrogen (in terms of nitrogen element), total phosphorus (in terms of P2O5) and total potassium (in terms of K2O) increased, and the potential for waste resource utilization also increased. Among the seven kinds of heavy (metalloid) metals with greater harm, such as Cd, Pb, Cr, Hg, As, Cu and Zn, except for As, the content of the remaining metal elements showed a downward trend; among the metal elements such as Na, Ca, Mg, Fe, and Mn, the content of the remaining elements, except Na, showed a downward trend. Therefore, the metal content in kitchen waste could be effectively controlled through the garbage sorting, so that the seed germination index could be increased, the biological toxic effect on plants reduced, and the environmental risk reduced. This study can provide a reference and basis for the planning of waste resource utilization and treatment facilities in Beijing.
2022, 40(12): 29-36.
doi: 10.13205/j.hjgc.202212005
Abstract:
The effects of hydrochar and pyrochar prepared by food waste on the production of caproate from food waste fermentation were investigated. The physicochemical properties of the biochar and microbial community were analyzed. The results showed that the maximum production of caproate was only 1.65 g COD/L in the blank. The addition of 5 g/L hydrochar and pyrochar both promoted the production of caproate with the maximum production at 3.64 g COD/L and 24.24 g COD/L, which were 2.2 times and 14.7 times that in the blank respectively. While excess hydrochar and pyrochar (10 g/L and 20 g/L) inhibited the production of caproate. The comparative analysis of the physicochemical properties of the biochar showed that the pyrochar could promote direct interspecies electron transferring, and pyrochar with a larger specific surface area could provide more attachment sites for the functional microbes for caproate production and enrich its abundance, promoting the conversion of ethanol and butyrate into caproate. Microbial community analysis showed that the relative abundance of functional microbes for caproate production including Clostridium_sensu_stricto_12, Caproiciproducens and Clostridium_sensu_stricto_11 in the 5 g/L pyrochar was 35.6%, 2.0% and 1.7%, respectively.
The effects of hydrochar and pyrochar prepared by food waste on the production of caproate from food waste fermentation were investigated. The physicochemical properties of the biochar and microbial community were analyzed. The results showed that the maximum production of caproate was only 1.65 g COD/L in the blank. The addition of 5 g/L hydrochar and pyrochar both promoted the production of caproate with the maximum production at 3.64 g COD/L and 24.24 g COD/L, which were 2.2 times and 14.7 times that in the blank respectively. While excess hydrochar and pyrochar (10 g/L and 20 g/L) inhibited the production of caproate. The comparative analysis of the physicochemical properties of the biochar showed that the pyrochar could promote direct interspecies electron transferring, and pyrochar with a larger specific surface area could provide more attachment sites for the functional microbes for caproate production and enrich its abundance, promoting the conversion of ethanol and butyrate into caproate. Microbial community analysis showed that the relative abundance of functional microbes for caproate production including Clostridium_sensu_stricto_12, Caproiciproducens and Clostridium_sensu_stricto_11 in the 5 g/L pyrochar was 35.6%, 2.0% and 1.7%, respectively.
2022, 40(12): 37-45.
doi: 10.13205/j.hjgc.202212006
Abstract:
Food waste has a complex composition and high moisture content. Although the pyrolysis process can achieve fast, harmless reduction and energy reuse of food waste, the process highly relies on external energy input. Thus the mass and energy evaluation for the pyrolysis process is very important. In this work, the mass distribution and energy flow for the pyrolysis of food waste were comprehensively investigated. We tried to achieve self-powered prolysis by burning the pyrolytic products. The pyrolysis experiments were conducted in a lab-scale fixed-bed reactor, and the influence of moisture on food waste and pyrolysis temperature was investigated. Moreover, based on the results of TG-DSC, an index (ERPC) was built for evaluating the potential of self-power. Results showed that when the temperature increased from 400 ℃ to 800 ℃, the solid product of pyrolysis decreased while the gaseous product increased. The liquid product increased firstly then decrease, and peaked at 500 ℃. Based on the analysis of the heating value of the products, the high pyrolysis temperature and moisture content weakened energy production. If all of the pyrolysis products (gas, oil and char) were burned, the moisture content of food waste should be lower than 40% for achieving self-power, and the pyrolysis temperature should be lower than 500 ℃. If only burning gas and oil products, the pyrolysis temperature should be lower than 600 ℃, and the moisture content lower than 10%. However, self-power can never be achieved under any conditions, if only burning prolysis gas.
Food waste has a complex composition and high moisture content. Although the pyrolysis process can achieve fast, harmless reduction and energy reuse of food waste, the process highly relies on external energy input. Thus the mass and energy evaluation for the pyrolysis process is very important. In this work, the mass distribution and energy flow for the pyrolysis of food waste were comprehensively investigated. We tried to achieve self-powered prolysis by burning the pyrolytic products. The pyrolysis experiments were conducted in a lab-scale fixed-bed reactor, and the influence of moisture on food waste and pyrolysis temperature was investigated. Moreover, based on the results of TG-DSC, an index (ERPC) was built for evaluating the potential of self-power. Results showed that when the temperature increased from 400 ℃ to 800 ℃, the solid product of pyrolysis decreased while the gaseous product increased. The liquid product increased firstly then decrease, and peaked at 500 ℃. Based on the analysis of the heating value of the products, the high pyrolysis temperature and moisture content weakened energy production. If all of the pyrolysis products (gas, oil and char) were burned, the moisture content of food waste should be lower than 40% for achieving self-power, and the pyrolysis temperature should be lower than 500 ℃. If only burning gas and oil products, the pyrolysis temperature should be lower than 600 ℃, and the moisture content lower than 10%. However, self-power can never be achieved under any conditions, if only burning prolysis gas.
2022, 40(12): 46-52,104.
doi: 10.13205/j.hjgc.202212007
Abstract:
The pilot-scale DANO and static fermentation were used as the main equipment of the primary and secondary fermentation process, respectively, and the appropriate control parameters were explored for the kitchen solid slag produced in the actual project. According to conditioners, C/N and moisture content, five batches of M1, M2, D1, D2 and D3 were set. Physicochemical indexes, ammonia volatilization, oxygen content, cellulase and protease content and final fertilizer quality indexes were detected to reveal the effect of DANO dynamic composting of kitchen solid residues under different conditions. The results showed that: 1) when the environmental temperature was in the range of 18.5 to 25.8 ℃, the temperature rise of the primary fermentation process of DANO was less affected by the environment. Compared with straw, sawdust had the characteristics of a slow heating rate, high peak temperature and long composting duration; 2) when the moisture content was controlled to be 50% to 60%, the temperature of the straw pile body in the high-temperature period was more than 55 ℃, and the maintenance time was longer than 7 days; 3) it was reasonable to control the initial C/N of the straw pile in the range of 23 to 27. To sum up, the composting cycle could be controlled in the range of 28 to 33 days by controlling the relevant conditions. Relevant important indexes including final product C/N, moisture content, total nutrient and pH all met the requirements of China’s Field Standard Organic Fertilizer (NY/T 525—2021)
The pilot-scale DANO and static fermentation were used as the main equipment of the primary and secondary fermentation process, respectively, and the appropriate control parameters were explored for the kitchen solid slag produced in the actual project. According to conditioners, C/N and moisture content, five batches of M1, M2, D1, D2 and D3 were set. Physicochemical indexes, ammonia volatilization, oxygen content, cellulase and protease content and final fertilizer quality indexes were detected to reveal the effect of DANO dynamic composting of kitchen solid residues under different conditions. The results showed that: 1) when the environmental temperature was in the range of 18.5 to 25.8 ℃, the temperature rise of the primary fermentation process of DANO was less affected by the environment. Compared with straw, sawdust had the characteristics of a slow heating rate, high peak temperature and long composting duration; 2) when the moisture content was controlled to be 50% to 60%, the temperature of the straw pile body in the high-temperature period was more than 55 ℃, and the maintenance time was longer than 7 days; 3) it was reasonable to control the initial C/N of the straw pile in the range of 23 to 27. To sum up, the composting cycle could be controlled in the range of 28 to 33 days by controlling the relevant conditions. Relevant important indexes including final product C/N, moisture content, total nutrient and pH all met the requirements of China’s Field Standard Organic Fertilizer (NY/T 525—2021)
2022, 40(12): 53-60.
doi: 10.13205/j.hjgc.202212008
Abstract:
In this study, a case project of dry-wet press separation of food waste-hydrothermal carbonization technology was taken as the research object. The operational efficiency of the food waste treatment project was evaluated, and the energy consumption and cost for per unit of food waste treatment were analyzed. The study results were as follows: the project treated an average of 115.32 t of food waste per day, with a waste mass reduction rate of 60.31%. The products obtained by dry-wet press separation-hydrothermal carbonization of food waste were dry waste and hydrothermal carbon, the moisture contents of them were 68.41% and 35.92%, and the low-level calorific values were 5029.61 J/g and 14424.80 J/g, respectively. The combustion performance of the products was substantially higher than raw food waste. The unit energy consumption of food waste treatment was 46.26 kW·h/t, of which hydrothermal carbonization treatment and wet and dry separation and pressing treatment accounted for 72.14% and 10.54%, respectively. The cost of food waste disposal was RMB 386.56/t. The project effectively achieves the reduction and reuse of food waste. The treatment products have promising applications in making waste-derived fuels, adsorbent materials, biochar-based fertilizers and soil amendments. This research provides reliable design reference and technical support for the development of urban food waste treatment projects.
In this study, a case project of dry-wet press separation of food waste-hydrothermal carbonization technology was taken as the research object. The operational efficiency of the food waste treatment project was evaluated, and the energy consumption and cost for per unit of food waste treatment were analyzed. The study results were as follows: the project treated an average of 115.32 t of food waste per day, with a waste mass reduction rate of 60.31%. The products obtained by dry-wet press separation-hydrothermal carbonization of food waste were dry waste and hydrothermal carbon, the moisture contents of them were 68.41% and 35.92%, and the low-level calorific values were 5029.61 J/g and 14424.80 J/g, respectively. The combustion performance of the products was substantially higher than raw food waste. The unit energy consumption of food waste treatment was 46.26 kW·h/t, of which hydrothermal carbonization treatment and wet and dry separation and pressing treatment accounted for 72.14% and 10.54%, respectively. The cost of food waste disposal was RMB 386.56/t. The project effectively achieves the reduction and reuse of food waste. The treatment products have promising applications in making waste-derived fuels, adsorbent materials, biochar-based fertilizers and soil amendments. This research provides reliable design reference and technical support for the development of urban food waste treatment projects.
2022, 40(12): 61-70,78.
doi: 10.13205/j.hjgc.202212009
Abstract:
Treatment of organic waste with anaerobic digestion (AD) is one of the most important steps in achieving carbon neutrality, but the treatment of biogas digestate limits the application and development of AD. In this paper, four typical types of organic waste digestate (i.e., food waste, sewage sludge, agricultural waste, and organic fraction of municipal solid waste) were studied. Their characteristics, nutrient and heavy metals concentrations were investigated, with the data derived from literature and internal unpublished databases of large and medium-sized AD plants. Furthermore, the bottleneck and future development of digestate treatment were discussed, by comparing the differences in policies, regulations, and standards from China and overseas. The opportunities and challenges of traditional digestate disposal means and the emerging resource-based technologies were evaluated, with a focus on transportation distance, scale-up capability, operation cost, and carbon emission, aiming to provide new information for policy formulation, technological development, and industrial applications.
Treatment of organic waste with anaerobic digestion (AD) is one of the most important steps in achieving carbon neutrality, but the treatment of biogas digestate limits the application and development of AD. In this paper, four typical types of organic waste digestate (i.e., food waste, sewage sludge, agricultural waste, and organic fraction of municipal solid waste) were studied. Their characteristics, nutrient and heavy metals concentrations were investigated, with the data derived from literature and internal unpublished databases of large and medium-sized AD plants. Furthermore, the bottleneck and future development of digestate treatment were discussed, by comparing the differences in policies, regulations, and standards from China and overseas. The opportunities and challenges of traditional digestate disposal means and the emerging resource-based technologies were evaluated, with a focus on transportation distance, scale-up capability, operation cost, and carbon emission, aiming to provide new information for policy formulation, technological development, and industrial applications.
2022, 40(12): 71-78.
doi: 10.13205/j.hjgc.202212010
Abstract:
Anaerobic fermentation (AF) of waste activated sludge (WAS) via electrochemical pretreatment (EPT) is a practical, effective and cost-saving protocol for volatile fatty acids (VFAs) production. However, AF performance is significantly affected by the different electrolytes during EPT. This study aimed to investigate the effects of different types of electrolytes (Control, NaCl, Na2SO4 and CaCl2) on VFAs production from AF of WAS via EPT with a current intensity at 1 A for 60 min. The results showed that by using 0.05 mol/L NaCl as the electrolyte during EPT, the amount of organic matter released from WAS, such as soluble COD, glycogen, protein etc., was the highest compared to other electrolytes. Thus the maximal VFAs accumulation during AF via EPT by using NaCl as the electrolyte reached 2625.8 mg COD/L, which was 51.6% higher than that of the control. These results indicated that EPT with NaCl as the electrolyte could effectively improve the hydrolysis of WAS, increase the amount of organic matter released from WAS and promote the enrichment of anaerobic fermentative bacteria (such as Firmicutes and Bacteroidetes). All of these subsequently promoted the AF of WAS and thus increased VFAs production, which in turn enhanced the resource recovery from WAS treatment.
Anaerobic fermentation (AF) of waste activated sludge (WAS) via electrochemical pretreatment (EPT) is a practical, effective and cost-saving protocol for volatile fatty acids (VFAs) production. However, AF performance is significantly affected by the different electrolytes during EPT. This study aimed to investigate the effects of different types of electrolytes (Control, NaCl, Na2SO4 and CaCl2) on VFAs production from AF of WAS via EPT with a current intensity at 1 A for 60 min. The results showed that by using 0.05 mol/L NaCl as the electrolyte during EPT, the amount of organic matter released from WAS, such as soluble COD, glycogen, protein etc., was the highest compared to other electrolytes. Thus the maximal VFAs accumulation during AF via EPT by using NaCl as the electrolyte reached 2625.8 mg COD/L, which was 51.6% higher than that of the control. These results indicated that EPT with NaCl as the electrolyte could effectively improve the hydrolysis of WAS, increase the amount of organic matter released from WAS and promote the enrichment of anaerobic fermentative bacteria (such as Firmicutes and Bacteroidetes). All of these subsequently promoted the AF of WAS and thus increased VFAs production, which in turn enhanced the resource recovery from WAS treatment.
2022, 40(12): 79-88.
doi: 10.13205/j.hjgc.202212011
Abstract:
Humic acid (HA) and Fulvic acid (FA) are organic components produced during the composting process, which have redox ability to act as electron shuttles to mediate the bioreduction of pollutants, due to the presence of active functional groups such as quinone and phenol groups. In this study, the electron transfer capacity (ETC) of HA and FA in different periods of pig manure composting was determined by electrochemical method, and the chemical structure changes of HA and FA and their effects on ETC were investigated by combining UV-Vis, FTIR and 3D-EEM. The results showed that from beginning to the end, the ETC of HA increased from 10.06 μmol e-/g C to 40.07 μmol e-/g C, and the ETC of FA increased from 15.36 μmol e-/g C to 69.73 μmol e-/g C, both of which showed a fluctuating increasing trend with time, and EDC was dominant in the electron transfer process. Spectral analysis showed that lignin-like substances in the compost would be transformed into humus with a high degree of polymerization after composting. Compared with the initial stage of composting, the degree of humification and aromatization of organic matter at the maturity stage increased, and the molecular weight also raised. Protein-like substances (component C4) gradually decreased in the composting process, which was easy to be used as carbon sources by microorganisms to convert into humic-like substances (component C2), and component C2 was relatively stable in composting. Correlation analysis showed that a decrease in protein-like substances and an increase in humification enhanced the ETC of HA and FA, and the electron transfer capacity of FA was more susceptible to the degree of humification.
Humic acid (HA) and Fulvic acid (FA) are organic components produced during the composting process, which have redox ability to act as electron shuttles to mediate the bioreduction of pollutants, due to the presence of active functional groups such as quinone and phenol groups. In this study, the electron transfer capacity (ETC) of HA and FA in different periods of pig manure composting was determined by electrochemical method, and the chemical structure changes of HA and FA and their effects on ETC were investigated by combining UV-Vis, FTIR and 3D-EEM. The results showed that from beginning to the end, the ETC of HA increased from 10.06 μmol e-/g C to 40.07 μmol e-/g C, and the ETC of FA increased from 15.36 μmol e-/g C to 69.73 μmol e-/g C, both of which showed a fluctuating increasing trend with time, and EDC was dominant in the electron transfer process. Spectral analysis showed that lignin-like substances in the compost would be transformed into humus with a high degree of polymerization after composting. Compared with the initial stage of composting, the degree of humification and aromatization of organic matter at the maturity stage increased, and the molecular weight also raised. Protein-like substances (component C4) gradually decreased in the composting process, which was easy to be used as carbon sources by microorganisms to convert into humic-like substances (component C2), and component C2 was relatively stable in composting. Correlation analysis showed that a decrease in protein-like substances and an increase in humification enhanced the ETC of HA and FA, and the electron transfer capacity of FA was more susceptible to the degree of humification.
2022, 40(12): 89-97.
doi: 10.13205/j.hjgc.202212012
Abstract:
Aerobic composting is one of the effective ways to recycle organic waste. However, the phosphorus supply of composting products is inferior to chemical fertilizers, resulting in weak competition of organic waste composts. Therefore, it is of great significance to regulate the availability of compost phosphorus resources and the transformation of phosphorus components. For phosphorus-decomposing microorganisms that can promote the activation of insoluble phosphorus in the composting process, the relative abundance and activity of functional microorganisms related to phosphorus transformation in the compost can be improved by microbial enhancement and microhabitat regulation, which can significantly improve the form of phosphorus components and increase the effective phosphorus content in composting. However, this process is vulnerable to multiple factors such as material sources, composting process conditions, microbial species relationships, etc. Therefore, this paper summarized the transformation law of phosphorus in compost and the dynamic characteristics of phosphorus decomposing microorganisms in compost, expounded on the strengthening methods of phosphorus decomposing microorganisms for endogenous control of the compost microenvironment, such as exogenous inoculation of phosphorus decomposing bacteria and addition of biochar in compost, and discussed the key limiting factors (temperature, C/N, moisture content, etc.) for the regulation of endogenous and exogenous phosphorus decomposing microorganisms in compost. It can provide a theoretical basis for exploring the directional transformation and regulation technology of phosphorus in compost and development of phosphorus-rich compost products in the future.
Aerobic composting is one of the effective ways to recycle organic waste. However, the phosphorus supply of composting products is inferior to chemical fertilizers, resulting in weak competition of organic waste composts. Therefore, it is of great significance to regulate the availability of compost phosphorus resources and the transformation of phosphorus components. For phosphorus-decomposing microorganisms that can promote the activation of insoluble phosphorus in the composting process, the relative abundance and activity of functional microorganisms related to phosphorus transformation in the compost can be improved by microbial enhancement and microhabitat regulation, which can significantly improve the form of phosphorus components and increase the effective phosphorus content in composting. However, this process is vulnerable to multiple factors such as material sources, composting process conditions, microbial species relationships, etc. Therefore, this paper summarized the transformation law of phosphorus in compost and the dynamic characteristics of phosphorus decomposing microorganisms in compost, expounded on the strengthening methods of phosphorus decomposing microorganisms for endogenous control of the compost microenvironment, such as exogenous inoculation of phosphorus decomposing bacteria and addition of biochar in compost, and discussed the key limiting factors (temperature, C/N, moisture content, etc.) for the regulation of endogenous and exogenous phosphorus decomposing microorganisms in compost. It can provide a theoretical basis for exploring the directional transformation and regulation technology of phosphorus in compost and development of phosphorus-rich compost products in the future.
2022, 40(12): 98-104.
doi: 10.13205/j.hjgc.202212013
Abstract:
With the increasing application of ethanol gasoline, the contaminated karst groundwater by its release has been concerned. Benzene, toluene, ethylbenzene, and xylene (referred to as BTEX) in gasoline can be effectively removed by in situ chemical oxidation using persulfate (PS). However, it’s still not clear whether the presence of ethanol affects the removal of BTEX by PS. In this paper, limestone particles, acting as the aqueous media, and gasoline BTEX (20 mg/L) combined with ethanol (500 mg/L or 5000 mg/L), acting as the pollutants, were used to form microcosms and simulate a contaminated karst groundwater environment. BTEX and ethanol removal effects by PS chemical oxidation were studied respectively, as well as their removal effects in coexistence. The results showed that 91% of BTEX was removed by PS in the first 28 days, with the first-order rate constants ranging from 0.006 to 0.349 d-1. Benzene was the most difficult to remove, followed by toluene. Ethanol was removed by PS with the pseudo-first-order rate constants ranging from 0.003 to 0.054 d-1, which was less than that of BTEX. The presence of ethanol could decrease the removal rate of BTEX, but couldn’t affect the removal priority of BTEX. The increase of PS concentration was beneficial to the removal of ethanol and BTEX, nevertheless, which could inhibit microbial activity, make the pH value drop more, and cause calcium sulfate precipitation. This work provides scientific data for in situ chemical oxidation of karst groundwater contaminated by ethanol gasoline.
With the increasing application of ethanol gasoline, the contaminated karst groundwater by its release has been concerned. Benzene, toluene, ethylbenzene, and xylene (referred to as BTEX) in gasoline can be effectively removed by in situ chemical oxidation using persulfate (PS). However, it’s still not clear whether the presence of ethanol affects the removal of BTEX by PS. In this paper, limestone particles, acting as the aqueous media, and gasoline BTEX (20 mg/L) combined with ethanol (500 mg/L or 5000 mg/L), acting as the pollutants, were used to form microcosms and simulate a contaminated karst groundwater environment. BTEX and ethanol removal effects by PS chemical oxidation were studied respectively, as well as their removal effects in coexistence. The results showed that 91% of BTEX was removed by PS in the first 28 days, with the first-order rate constants ranging from 0.006 to 0.349 d-1. Benzene was the most difficult to remove, followed by toluene. Ethanol was removed by PS with the pseudo-first-order rate constants ranging from 0.003 to 0.054 d-1, which was less than that of BTEX. The presence of ethanol could decrease the removal rate of BTEX, but couldn’t affect the removal priority of BTEX. The increase of PS concentration was beneficial to the removal of ethanol and BTEX, nevertheless, which could inhibit microbial activity, make the pH value drop more, and cause calcium sulfate precipitation. This work provides scientific data for in situ chemical oxidation of karst groundwater contaminated by ethanol gasoline.
2022, 40(12): 105-111.
doi: 10.13205/j.hjgc.202212014
Abstract:
To explore the influence of the spatial layout of rainwater garden in the building community on the runoff process, a 1D and 2D coupling hydrodynamic model with SWMM (storm flood management model) pipe network module and GAST (surface hydrodynamic numerical model based on GPU acceleration technology) was adopted in this research, and the runoff process under the measured rainfall condition was simulated and calculated by taking Tianfuheyuan community in Xixian New Area as an example. The rainwater gardens were arranged in the upper, middle and lower reaches of the Tianfuheyuan community respectively, to simulate the regulation effect on the outlet runoff of the pipe network, and more than 6 return periods and 18 typical conditions were conducted in this paper. The results showed that the coupling model could be used to accurately simulate the process of urban pipe network drainage and surface inundation; the Nash efficiency coefficients were 0.80 and 0.76 in the two measured rainfall events, representing good accordance with the measured data. With the increase in design rainfall return period, the total runoff control rate decreased gradually. Under the same return period, the total runoff control rate of the rainwater garden arranged on the downstream side was increased by 5.33% to 8.74% compared with that on the upstream side, and that’s an obvious improvement. The research results can provide a reference for optimizing the spatial layout of rainwater gardens in building communities.
To explore the influence of the spatial layout of rainwater garden in the building community on the runoff process, a 1D and 2D coupling hydrodynamic model with SWMM (storm flood management model) pipe network module and GAST (surface hydrodynamic numerical model based on GPU acceleration technology) was adopted in this research, and the runoff process under the measured rainfall condition was simulated and calculated by taking Tianfuheyuan community in Xixian New Area as an example. The rainwater gardens were arranged in the upper, middle and lower reaches of the Tianfuheyuan community respectively, to simulate the regulation effect on the outlet runoff of the pipe network, and more than 6 return periods and 18 typical conditions were conducted in this paper. The results showed that the coupling model could be used to accurately simulate the process of urban pipe network drainage and surface inundation; the Nash efficiency coefficients were 0.80 and 0.76 in the two measured rainfall events, representing good accordance with the measured data. With the increase in design rainfall return period, the total runoff control rate decreased gradually. Under the same return period, the total runoff control rate of the rainwater garden arranged on the downstream side was increased by 5.33% to 8.74% compared with that on the upstream side, and that’s an obvious improvement. The research results can provide a reference for optimizing the spatial layout of rainwater gardens in building communities.
2022, 40(12): 112-120.
doi: 10.13205/j.hjgc.202212015
Abstract:
Vermifiltration (VF) is a low-carbon and eco-friendly technology. Based on the excellent excess sludge reduction efficacy, the removal effects of newly emerging pollutants, antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB) were evaluated, with a conventional biofilter (BF, no earthworm) as a control. The results indicated that the VF increased the removal rate of ARB (tetracycline resistant bacteria, sulfamethoxazole resistance bacteria and double resistance bacteria) by more than 25%, and exhibited higher but selective ARGs (tetO, tetM, tetQ, tetW, sul1, sul2) removal rates, generally increased by more than 20%, compared to the BF. Moreover, the average removal rate of intI1 by VF was 98.24%, reducing the risk of horizontal transmission of ARGs. In summer and winter, compared with the BF, the removal of ARGs and ARB by the VF increased by more than 15%, indicating that the addition of earthworms weakened the inhibitory effect of low and high temperatures. Conclusively, vermifiltration could effectively improve the removal rates of various ARGs and ARB in the excess sludge by the excellent excess sludge removal, which provides a reference for the ARGs and ARB removal assisted by the earthworms.
Vermifiltration (VF) is a low-carbon and eco-friendly technology. Based on the excellent excess sludge reduction efficacy, the removal effects of newly emerging pollutants, antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB) were evaluated, with a conventional biofilter (BF, no earthworm) as a control. The results indicated that the VF increased the removal rate of ARB (tetracycline resistant bacteria, sulfamethoxazole resistance bacteria and double resistance bacteria) by more than 25%, and exhibited higher but selective ARGs (tetO, tetM, tetQ, tetW, sul1, sul2) removal rates, generally increased by more than 20%, compared to the BF. Moreover, the average removal rate of intI1 by VF was 98.24%, reducing the risk of horizontal transmission of ARGs. In summer and winter, compared with the BF, the removal of ARGs and ARB by the VF increased by more than 15%, indicating that the addition of earthworms weakened the inhibitory effect of low and high temperatures. Conclusively, vermifiltration could effectively improve the removal rates of various ARGs and ARB in the excess sludge by the excellent excess sludge removal, which provides a reference for the ARGs and ARB removal assisted by the earthworms.
2022, 40(12): 128-133.
doi: 10.13205/j.hjgc.202212017
Abstract:
To improve the pollutant removal efficiency of electroplating wastewater, the removal efficiencies of organic matter, nitrogen and phosphorus by anaerobic anoxic aerobic (AAO)-biofilm coupling process were discussed. The experimental results showed that the AAO-biofilm process owned good operation performance for treating refractory organic matters in electroplating wastewater, and the COD removal rate was stable at about 89%. The majority of nitrogen was removed through nitrification in the aerobic tank and denitrification in the anoxic tank. The nitrogen removal rate of the system reached 70%~80% after 60 days operation. Refractory organics affected the removal efficiency of NH4+-N and COD and made a time gap between them. The change of NH4+-N lagged behind COD. The phosphorus removal performance of the AAO-biofilm process tended to be stable after 50 days operation, the effluent concentration was less than 1 mg/L, and the removal rate was more than 65%. Phosphorus was mainly removed through anaerobic release and aerobic absorption of the functional microorganisms.
To improve the pollutant removal efficiency of electroplating wastewater, the removal efficiencies of organic matter, nitrogen and phosphorus by anaerobic anoxic aerobic (AAO)-biofilm coupling process were discussed. The experimental results showed that the AAO-biofilm process owned good operation performance for treating refractory organic matters in electroplating wastewater, and the COD removal rate was stable at about 89%. The majority of nitrogen was removed through nitrification in the aerobic tank and denitrification in the anoxic tank. The nitrogen removal rate of the system reached 70%~80% after 60 days operation. Refractory organics affected the removal efficiency of NH4+-N and COD and made a time gap between them. The change of NH4+-N lagged behind COD. The phosphorus removal performance of the AAO-biofilm process tended to be stable after 50 days operation, the effluent concentration was less than 1 mg/L, and the removal rate was more than 65%. Phosphorus was mainly removed through anaerobic release and aerobic absorption of the functional microorganisms.
2022, 40(12): 134-141.
doi: 10.13205/j.hjgc.202212018
Abstract:
Aiming at the problem of low early strength of steel slag-desulfurized ash-based cementitious materials, the effects of different early strength agents on the compressive strength and hydration performance of steel slag-desulfurized ash-based cementitious materials were studied. Experimental research results showed that when the desulfurization ash content was 15%, the 3-day compressive strength was 3.65 MPa, which was 48.95% lower than the blank sample. Using quicklime, calcium chloride, calcium formate, silica fume, aluminum sulfate and other composite early-strength agents to modify steel slag-desulfurization ash-based cementitious materials, the 3-day compressive strength reached 17.89 MPa, which was 4.90 times that of the blank sample, and met the cement compressive strength requirements of composite Portland cement 42.5 grade, specified in China’s national standard, GB 175—2007. Through XRD, SEM, FI-RT, XPS and DTG tests, it was found that the main hydration products of cementitious materials were monosulfur hydrated calcium aluminum sulfide, hydrated calcium chloroaluminate, and hydrated calcium silicate, and Friedel’s salt.
Aiming at the problem of low early strength of steel slag-desulfurized ash-based cementitious materials, the effects of different early strength agents on the compressive strength and hydration performance of steel slag-desulfurized ash-based cementitious materials were studied. Experimental research results showed that when the desulfurization ash content was 15%, the 3-day compressive strength was 3.65 MPa, which was 48.95% lower than the blank sample. Using quicklime, calcium chloride, calcium formate, silica fume, aluminum sulfate and other composite early-strength agents to modify steel slag-desulfurization ash-based cementitious materials, the 3-day compressive strength reached 17.89 MPa, which was 4.90 times that of the blank sample, and met the cement compressive strength requirements of composite Portland cement 42.5 grade, specified in China’s national standard, GB 175—2007. Through XRD, SEM, FI-RT, XPS and DTG tests, it was found that the main hydration products of cementitious materials were monosulfur hydrated calcium aluminum sulfide, hydrated calcium chloroaluminate, and hydrated calcium silicate, and Friedel’s salt.
2022, 40(12): 142-150,179.
doi: 10.13205/j.hjgc.202212019
Abstract:
Since the distribution of air pollution sources is influenced by topography, landform and meteorology, the distribution of air pollution data in space is of arbitrary shapes and densities. To more accurately mine the rule of air pollution, this paper proposed a clustering model based on the DP algorithm for discovering the backbones of the cluster. The model could directly group pollution data without statistical analysis and extract key information from air pollution data by keeping the distribution unchanged, so as to excavate the change law of air pollution more accurately. The proposed clustering model and the k-Means algorithm were compared and analyzed on the three hourly pollutant concentration datasets monitored in January of 2017, 2019 and 2021 in Lanzhou respectively. In these three datasets, our model could more clearly mine the pollution data. The key pollution data accounted for 59.0%, 57.2% and 69.0% respectively in the backbones of pollution cluster, and the primary pollutants causing pollution were NO2 and particulate matter. To reflect the applicability of the model, we analyzed our model on the pollution data in Lanzhou in January 2021, then found that the variation of air pollution in that month was caused by the joint or alternate action of pollutants NO2 and PM10, the hourly variation trend of pollution showed a bimodal pattern both on the number of contaminated hours and the occurrence frequency of primary pollutants (NO2 and PM10), and Chengguan District was the polluted area. The validity of the model was tested using the causes analysis of the above pollution laws, which made the model practical and effective for extracting key air pollution data without changing its complex distribution.
Since the distribution of air pollution sources is influenced by topography, landform and meteorology, the distribution of air pollution data in space is of arbitrary shapes and densities. To more accurately mine the rule of air pollution, this paper proposed a clustering model based on the DP algorithm for discovering the backbones of the cluster. The model could directly group pollution data without statistical analysis and extract key information from air pollution data by keeping the distribution unchanged, so as to excavate the change law of air pollution more accurately. The proposed clustering model and the k-Means algorithm were compared and analyzed on the three hourly pollutant concentration datasets monitored in January of 2017, 2019 and 2021 in Lanzhou respectively. In these three datasets, our model could more clearly mine the pollution data. The key pollution data accounted for 59.0%, 57.2% and 69.0% respectively in the backbones of pollution cluster, and the primary pollutants causing pollution were NO2 and particulate matter. To reflect the applicability of the model, we analyzed our model on the pollution data in Lanzhou in January 2021, then found that the variation of air pollution in that month was caused by the joint or alternate action of pollutants NO2 and PM10, the hourly variation trend of pollution showed a bimodal pattern both on the number of contaminated hours and the occurrence frequency of primary pollutants (NO2 and PM10), and Chengguan District was the polluted area. The validity of the model was tested using the causes analysis of the above pollution laws, which made the model practical and effective for extracting key air pollution data without changing its complex distribution.
2022, 40(12): 151-156,164.
doi: 10.13205/j.hjgc.202212020
Abstract:
To explore the path to carbon emission peaking of Henan, China and meet the strategic need of the local authorities, in this paper, the data of twelve factors of social, economic, energy consumption, and resources in Henan from 2001 to 2020 were selected, and the Lasso-BP neural network method was used to establish a prediction model of carbon emission in Henan province. Based on the regression analysis of the data of the 12 indexes, six different development paths were designed to predict the carbon emission of Henan from 2021 to 2035. The results showed that: 1) among the twelve factors, six key factors affecting carbon peaking were the share of coal consumption, energy consumption per unit of GDP, forest coverage, total energy consumption, the share of secondary industry GDP, and private car ownership; 2) paths 1 to 4 pursuing single-factor development were all unable to achieve carbon peaking in 2030. Under paths 5 and 6, Henan would reach peak carbon in 2029. Compared with path 5, the peak CO2 emission of path 6 was 2.53 Mt lower, with a peak of 510.91 Mt CO2; 3) to achieve the carbon emission peak, the average annual growth rates of coal consumption, energy consumption per unit of GDP, forest coverage, total energy consumption, the share of secondary industry in GDP, and private car ownership should be controlled at -4.0% and -5.0%, -3.5% and -4.0%, 2.0% and 3.0%, 0.5% and 0.4%, -1.5% and -2.0%,7.5% and 7.0%, during the 14th Five-Year Plan and the 15th Five-Year Plan Period respectively.
To explore the path to carbon emission peaking of Henan, China and meet the strategic need of the local authorities, in this paper, the data of twelve factors of social, economic, energy consumption, and resources in Henan from 2001 to 2020 were selected, and the Lasso-BP neural network method was used to establish a prediction model of carbon emission in Henan province. Based on the regression analysis of the data of the 12 indexes, six different development paths were designed to predict the carbon emission of Henan from 2021 to 2035. The results showed that: 1) among the twelve factors, six key factors affecting carbon peaking were the share of coal consumption, energy consumption per unit of GDP, forest coverage, total energy consumption, the share of secondary industry GDP, and private car ownership; 2) paths 1 to 4 pursuing single-factor development were all unable to achieve carbon peaking in 2030. Under paths 5 and 6, Henan would reach peak carbon in 2029. Compared with path 5, the peak CO2 emission of path 6 was 2.53 Mt lower, with a peak of 510.91 Mt CO2; 3) to achieve the carbon emission peak, the average annual growth rates of coal consumption, energy consumption per unit of GDP, forest coverage, total energy consumption, the share of secondary industry in GDP, and private car ownership should be controlled at -4.0% and -5.0%, -3.5% and -4.0%, 2.0% and 3.0%, 0.5% and 0.4%, -1.5% and -2.0%,7.5% and 7.0%, during the 14th Five-Year Plan and the 15th Five-Year Plan Period respectively.
2022, 40(12): 157-164.
doi: 10.13205/j.hjgc.202212021
Abstract:
Catalytic filters are low-cost and high-efficiency for synergistic removal of NOx and particulates, which have become the development direction of air pollution control technology in the cement and steel industries. The morphology of the catalytic interface in the catalytic filter has a significant influence on its denitration performance. MnCeOx/P84 catalytic filter with a spherical catalytic interface (α-MnCeOx/P84) was prepared, and its NOx removal performance was investigated. The results showed that the NOx removal efficiency of α-MnCeOx/P84 was 86.9% at 130 ℃ and 97% above at 160 ℃ to 190 ℃ when the MnCeOx loading was 60 g/m2. At the same time, α-MnceOx/P84 had good SO2 resistance and stability, and the NOx removal rate of α-MnceOx/P84 could reach 83% at 190 ℃ after introducing SO2 with a volume fraction of 0.003%. When the injection of SO2 was stopped, NOx removal rate of α-MnceOx/P84 increased and stabilized at about 93%. After 200 hours denitrification reaction test, the denitrification efficiency and catalyst loading of α-MnCeOx/P84 did not decrease significantly. The characterization results showed that the spherical MnCeOx active component in α-MnCeOx/P84 was present in weak crystalline form, tightly wrapped around the surface of the filter fiber, uniformly dispersed, and the mesopore was the main pore structure of the MnCeOx catalyst, which could provide a channel for the catalytic reaction to proceed. Further analysis of H2-TPR and In-situ DRIFTS showed that α-MnCeOx/P84 had good redox ability at 100 ℃ to 200 ℃ and had abundant Lewis acid sites and Brnsted acid sites, which provided an important guarantee for its superior low-temperature NH3-SCR denitrification performance. MnCeOx/P84 catalyst filter with a spherical catalytic interface had the characteristics of low load and high stability, which laid a foundation for the promotion and application of dust and NOx removal over catalytic filters.
Catalytic filters are low-cost and high-efficiency for synergistic removal of NOx and particulates, which have become the development direction of air pollution control technology in the cement and steel industries. The morphology of the catalytic interface in the catalytic filter has a significant influence on its denitration performance. MnCeOx/P84 catalytic filter with a spherical catalytic interface (α-MnCeOx/P84) was prepared, and its NOx removal performance was investigated. The results showed that the NOx removal efficiency of α-MnCeOx/P84 was 86.9% at 130 ℃ and 97% above at 160 ℃ to 190 ℃ when the MnCeOx loading was 60 g/m2. At the same time, α-MnceOx/P84 had good SO2 resistance and stability, and the NOx removal rate of α-MnceOx/P84 could reach 83% at 190 ℃ after introducing SO2 with a volume fraction of 0.003%. When the injection of SO2 was stopped, NOx removal rate of α-MnceOx/P84 increased and stabilized at about 93%. After 200 hours denitrification reaction test, the denitrification efficiency and catalyst loading of α-MnCeOx/P84 did not decrease significantly. The characterization results showed that the spherical MnCeOx active component in α-MnCeOx/P84 was present in weak crystalline form, tightly wrapped around the surface of the filter fiber, uniformly dispersed, and the mesopore was the main pore structure of the MnCeOx catalyst, which could provide a channel for the catalytic reaction to proceed. Further analysis of H2-TPR and In-situ DRIFTS showed that α-MnCeOx/P84 had good redox ability at 100 ℃ to 200 ℃ and had abundant Lewis acid sites and Brnsted acid sites, which provided an important guarantee for its superior low-temperature NH3-SCR denitrification performance. MnCeOx/P84 catalyst filter with a spherical catalytic interface had the characteristics of low load and high stability, which laid a foundation for the promotion and application of dust and NOx removal over catalytic filters.
2022, 40(12): 165-172.
doi: 10.13205/j.hjgc.202212022
Abstract:
A water-energy-carbon footprint nexus model was proposed to be used for calculating the energy consumption and carbon footprint of sports venues. Meanwhile, the uncertainty of the water system carbon footprint of sports venues was analyzed, and the definition of the characteristic emission factors was proposed. By analyzing the characteristics of most kinds of sports venues, the emission factor method was adopted in the model including domestic water system, air conditioning water system and sports water system of sports venues, in which the energy consumption and carbon emission of water intake, water supply, water use and drainage were analyzed. The numerical uncertainty analysis was carried out by combining data quality evaluation with random analysis. The scenario uncertainty analysis was performed by scenario analysis and sensitivity analysis for identifying and quantifying the influencing factors. A case study of the National Sliding Centre in Yanqing Area of 2022 Beijing Winter Olympic Games was conducted. The results showed that the carbon emissions of ice making and heating were the highest at 161.2 t CO2 and 114.3 t CO2 respectively in the operation stage. The carbon emissions were reduced by 65.4% under the scenario of advanced technology+clean energy, and the coefficient of variation was 0.183~0.187. The research indicated the measures of adopting green electricity, water-saving sanitary wares, recycling water and improving energy efficiency achieved stable emission reduction effect.
A water-energy-carbon footprint nexus model was proposed to be used for calculating the energy consumption and carbon footprint of sports venues. Meanwhile, the uncertainty of the water system carbon footprint of sports venues was analyzed, and the definition of the characteristic emission factors was proposed. By analyzing the characteristics of most kinds of sports venues, the emission factor method was adopted in the model including domestic water system, air conditioning water system and sports water system of sports venues, in which the energy consumption and carbon emission of water intake, water supply, water use and drainage were analyzed. The numerical uncertainty analysis was carried out by combining data quality evaluation with random analysis. The scenario uncertainty analysis was performed by scenario analysis and sensitivity analysis for identifying and quantifying the influencing factors. A case study of the National Sliding Centre in Yanqing Area of 2022 Beijing Winter Olympic Games was conducted. The results showed that the carbon emissions of ice making and heating were the highest at 161.2 t CO2 and 114.3 t CO2 respectively in the operation stage. The carbon emissions were reduced by 65.4% under the scenario of advanced technology+clean energy, and the coefficient of variation was 0.183~0.187. The research indicated the measures of adopting green electricity, water-saving sanitary wares, recycling water and improving energy efficiency achieved stable emission reduction effect.
2022, 40(12): 173-179.
doi: 10.13205/j.hjgc.202212023
Abstract:
To explore the effects of crude oil contamination on the particle size and stability of soil aggregates, taking the simulated polluted soil as the research object, parameters such as particle size of soil mechanically stable aggregates, particle size of water-stable aggregates and crude oil concentration of aggregates under the condition of different crude oil content (2%, 5%, 10%) and different polluting duration (2 d, 15 d, 30 d) were studied. The results showed that: the proportions of mechanically stable aggregates and water-stable aggregates with a particle size of 2 mm above were increased by crude oil, and the proportions of mechanically stable aggregates and water-stable aggregates with a particle size of less than 0.25 mm were reduced. With the polluting duration prolonged, the proportion of aggregates with a particle size of 2 mm above increased significantly, and the proportion of aggregates with a particle size of 0.25mm below decreased significantly. The crude oil concentration of aggregates with the same particle size increased with the increase of total oil content of the soil. The distribution of crude oil in aggregates with different particle sizes decreased in the order of 2 mm above >0.25 to 2 mm>0.25 mm below. The distribution of crude oil in aggregates with a particle size of 2 mm above accounted for more than 60% of the total crude oil. Crude oil changed the particle sizes of soil aggregates, increased the stability of aggregates and promoted the formation of large aggregates with a particle size of 2 mm above. Crude oil was mainly distributed in large aggregates.
To explore the effects of crude oil contamination on the particle size and stability of soil aggregates, taking the simulated polluted soil as the research object, parameters such as particle size of soil mechanically stable aggregates, particle size of water-stable aggregates and crude oil concentration of aggregates under the condition of different crude oil content (2%, 5%, 10%) and different polluting duration (2 d, 15 d, 30 d) were studied. The results showed that: the proportions of mechanically stable aggregates and water-stable aggregates with a particle size of 2 mm above were increased by crude oil, and the proportions of mechanically stable aggregates and water-stable aggregates with a particle size of less than 0.25 mm were reduced. With the polluting duration prolonged, the proportion of aggregates with a particle size of 2 mm above increased significantly, and the proportion of aggregates with a particle size of 0.25mm below decreased significantly. The crude oil concentration of aggregates with the same particle size increased with the increase of total oil content of the soil. The distribution of crude oil in aggregates with different particle sizes decreased in the order of 2 mm above >0.25 to 2 mm>0.25 mm below. The distribution of crude oil in aggregates with a particle size of 2 mm above accounted for more than 60% of the total crude oil. Crude oil changed the particle sizes of soil aggregates, increased the stability of aggregates and promoted the formation of large aggregates with a particle size of 2 mm above. Crude oil was mainly distributed in large aggregates.
2022, 40(12): 180-186.
doi: 10.13205/j.hjgc.202212024
Abstract:
As for the limited space and complex air flow field in large indoor places, research on the spread of aerosol-borne viruses in such large enclosed spaces is of great significance for preventing spreading of infectious viruses. Taking a shelter hospital in Wuhan temporarily refitted from a stadium in the COVID-19 epidemic in 2020 as the research object, the air flow field in the shelter was analyzed by numerical simulation, and the DPM model (discrete phase particle model) was used to simulate the virus-carrying distribution and diffusion of aerosol particles in the shelter. The effects of natural ventilation, forced ventilation, air distribution in air ducts and bottom suction on particle distribution were also studied. The results of the numerical simulation showed that the aerosol diffusion was effectively suppressed, when the air distribution of the air duct was matched with the bottom suction, and when the wind pressure of the air distribution in the air duct was 50 kPa, the effect of particle removal was the best.
As for the limited space and complex air flow field in large indoor places, research on the spread of aerosol-borne viruses in such large enclosed spaces is of great significance for preventing spreading of infectious viruses. Taking a shelter hospital in Wuhan temporarily refitted from a stadium in the COVID-19 epidemic in 2020 as the research object, the air flow field in the shelter was analyzed by numerical simulation, and the DPM model (discrete phase particle model) was used to simulate the virus-carrying distribution and diffusion of aerosol particles in the shelter. The effects of natural ventilation, forced ventilation, air distribution in air ducts and bottom suction on particle distribution were also studied. The results of the numerical simulation showed that the aerosol diffusion was effectively suppressed, when the air distribution of the air duct was matched with the bottom suction, and when the wind pressure of the air distribution in the air duct was 50 kPa, the effect of particle removal was the best.
2022, 40(12): 187-195,230.
doi: 10.13205/j.hjgc.202212025
Abstract:
In China, the output of coal gangue is large, and the utilization rate is low. A large amount of accumulation has not been reasonably utilized, resulting in the wasting of land resources and environmental pollution. In this paper, coal gangue was used as the main raw material, and porous materials were obtained by adding aluminum powder for foaming and curing, and then fermented with waste organic matter and carbon-containing auxiliary materials to make solid waste-based soil conditioners. The soil physicochemical properties of spraying solid waste-based soil conditioner (SWSC), arbuscular mycorrhizal fungi (AMF) and solid waste-based soil conditioner coupled with mycorrhizal fungi (SWSC+AMF), and their effects on the growth of typical plants in the mining area were compared. The accumulation of heavy metals in plants under different treatments was compared. A proportion of gangue and cement at 85%∶15% was best for making the porous material. Chicken manure and weathered coal were selected as organic matter and carbon excipients. When the ratio of porous particles, chicken manure and weathered coal was 4∶2∶4, the prepared solid waste-based soil conditioner was the best. When the mass ratio of porous particles, chicken manure and weathered coal was 4∶2∶4, the prepared solid waste-based soil agent conditioner was the best. The whole process of preparation and application of soil conditioners was evaluated for heavy metal safety, and the heavy metal content met the limit values in the corresponding national standards. The content of organic matter in the soil sprayed with SWSC+AMF was 35.2 mg/kg, the content of available potassium and available phosphorus was 261 mg/kg and 278 mg/kg, and the content of alkaline phosphatase could reach 293.07 mg/kg. Moreover, spraying SWSC+AMF could promote the growth of plant height and root length, which can effectively reduce the accumulation of Cd, Pb and Ni element in Elymus grass, and improve soil structure and fertility.
In China, the output of coal gangue is large, and the utilization rate is low. A large amount of accumulation has not been reasonably utilized, resulting in the wasting of land resources and environmental pollution. In this paper, coal gangue was used as the main raw material, and porous materials were obtained by adding aluminum powder for foaming and curing, and then fermented with waste organic matter and carbon-containing auxiliary materials to make solid waste-based soil conditioners. The soil physicochemical properties of spraying solid waste-based soil conditioner (SWSC), arbuscular mycorrhizal fungi (AMF) and solid waste-based soil conditioner coupled with mycorrhizal fungi (SWSC+AMF), and their effects on the growth of typical plants in the mining area were compared. The accumulation of heavy metals in plants under different treatments was compared. A proportion of gangue and cement at 85%∶15% was best for making the porous material. Chicken manure and weathered coal were selected as organic matter and carbon excipients. When the ratio of porous particles, chicken manure and weathered coal was 4∶2∶4, the prepared solid waste-based soil conditioner was the best. When the mass ratio of porous particles, chicken manure and weathered coal was 4∶2∶4, the prepared solid waste-based soil agent conditioner was the best. The whole process of preparation and application of soil conditioners was evaluated for heavy metal safety, and the heavy metal content met the limit values in the corresponding national standards. The content of organic matter in the soil sprayed with SWSC+AMF was 35.2 mg/kg, the content of available potassium and available phosphorus was 261 mg/kg and 278 mg/kg, and the content of alkaline phosphatase could reach 293.07 mg/kg. Moreover, spraying SWSC+AMF could promote the growth of plant height and root length, which can effectively reduce the accumulation of Cd, Pb and Ni element in Elymus grass, and improve soil structure and fertility.
2022, 40(12): 196-201,280.
doi: 10.13205/j.hjgc.202212026
Abstract:
In order to investigate the domestic life sewage discharge situation of urban residents in South China and the change of water quality inside the plot, taking Nanning as an example, three representative living quarters were selected to monitor the water quality and quantity of the building sewage pipes and outlets throughout the day. The results showed that the peak period of water volume throughout the day was 7:00—9:00, 11:00—13:00, and 20:00—23:00, and the peak period of water quality throughout the day was 6:00—9:00, 11:00—13:00 and 18:00—21:00, sewage pollutants discharge was closely related to the characteristics of residential communities. Nitrogen and phosphorus pollutants in domestic sewage were highly homologous, more than 80% of which come from human excretion. There was no correlation between detergent content and phosphorus compounds’ concentration. After the septic tank, the water quality was still attenuating. After the septic tank, the COD of every 1 km sewage pipeline could be reduced by 34 mg/L, and the reduction rate was 11.7%. Based on the water quality of building sewage pipes and daily water consumption per capita, the per capita domestic sewage discharge coefficient of COD, NH3-N, TN, TP, BOD5, and LAS of the selected urban residents was 52.2, 7.1, 8.7, 0.61, 25.4, 0.49 g/(p·d), respectively.
In order to investigate the domestic life sewage discharge situation of urban residents in South China and the change of water quality inside the plot, taking Nanning as an example, three representative living quarters were selected to monitor the water quality and quantity of the building sewage pipes and outlets throughout the day. The results showed that the peak period of water volume throughout the day was 7:00—9:00, 11:00—13:00, and 20:00—23:00, and the peak period of water quality throughout the day was 6:00—9:00, 11:00—13:00 and 18:00—21:00, sewage pollutants discharge was closely related to the characteristics of residential communities. Nitrogen and phosphorus pollutants in domestic sewage were highly homologous, more than 80% of which come from human excretion. There was no correlation between detergent content and phosphorus compounds’ concentration. After the septic tank, the water quality was still attenuating. After the septic tank, the COD of every 1 km sewage pipeline could be reduced by 34 mg/L, and the reduction rate was 11.7%. Based on the water quality of building sewage pipes and daily water consumption per capita, the per capita domestic sewage discharge coefficient of COD, NH3-N, TN, TP, BOD5, and LAS of the selected urban residents was 52.2, 7.1, 8.7, 0.61, 25.4, 0.49 g/(p·d), respectively.
2022, 40(12): 202-210.
doi: 10.13205/j.hjgc.202212027
Abstract:
To explore the removal of dimethyl phthalate (DMP) in a vegetation-activated sludge process (V-ASP), DMP with influent concentration gradients of 50 mg/L, 5 mg/L, 500 μg/L, 50 μg/L and 0 μg/L was set to investigate the effects of conventional pollutants effluent concentration, the changes of plant and microorganism and its removal efficiency. The results showed that DMP had little effect on the removal of conventional pollutants in V-ASP, and the removal efficiency of TN got improved when the concentration of DMP was greater than or equal to 500 μg/L. The removal rates of 50 mg/L, 5 mg/L, 500 μg/L and 50 μg/L DMP in V-ASP were 99.97%, 99.51%, 94.19% and 83.68%, respectively. The main removal pathway of DMP in V-ASP was found out to be microbial catabolism, and the proportion of DMP absorbed by plants was less than 1.12%. When the influent DMP concentration reached 5 mg/L, the plant in V-ASP was significantly inhibited. High-throughput sequencing results showed that DMP had a certain effect on the microbial diversity of activated sludge and rhizosphere sludge in V-ASP. The relative abundance of Proteobacteria was the highest in the microbial community, and that of Rhodococcus increased with the increase of DMP concentration.
To explore the removal of dimethyl phthalate (DMP) in a vegetation-activated sludge process (V-ASP), DMP with influent concentration gradients of 50 mg/L, 5 mg/L, 500 μg/L, 50 μg/L and 0 μg/L was set to investigate the effects of conventional pollutants effluent concentration, the changes of plant and microorganism and its removal efficiency. The results showed that DMP had little effect on the removal of conventional pollutants in V-ASP, and the removal efficiency of TN got improved when the concentration of DMP was greater than or equal to 500 μg/L. The removal rates of 50 mg/L, 5 mg/L, 500 μg/L and 50 μg/L DMP in V-ASP were 99.97%, 99.51%, 94.19% and 83.68%, respectively. The main removal pathway of DMP in V-ASP was found out to be microbial catabolism, and the proportion of DMP absorbed by plants was less than 1.12%. When the influent DMP concentration reached 5 mg/L, the plant in V-ASP was significantly inhibited. High-throughput sequencing results showed that DMP had a certain effect on the microbial diversity of activated sludge and rhizosphere sludge in V-ASP. The relative abundance of Proteobacteria was the highest in the microbial community, and that of Rhodococcus increased with the increase of DMP concentration.
2022, 40(12): 211-216.
doi: 10.13205/j.hjgc.202212028
Abstract:
The effect of an Achromobacter denitrificans strain 2-5, with the function of iron oxidation and aerobic denitrification, on enhancing the denitrification performance of an SBR reactor and its bacterial community structure was studied in this paper. The results showed that the addition of Fe0 and Achromobacter denitricans strain 2-5 could improve the removal efficiency of NH4+-N and TN in the SBR reactor. Compared with the ordinary SBR reactors, the average removal rates of NH4+-N and TN were increased by 4.13% and 15.73%. Through high-throughput sequencing analysis, differences were found in the composition of microbial community structure in each reactor. At the phylum level, Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes were the dominant phyla. The addition of Fe0 and Achromobacter denitrificans strain 2-5 increased the diversity of bacteria with aerobic denitrification function in the reactor and strengthened the denitrification effect of the SBR reactor. The research results provide a theoretical basis for Fe0 to promote the metabolic growth of aerobic denitrifying bacteria and are conducive to the practical application of aerobic denitrifying bacteria.
The effect of an Achromobacter denitrificans strain 2-5, with the function of iron oxidation and aerobic denitrification, on enhancing the denitrification performance of an SBR reactor and its bacterial community structure was studied in this paper. The results showed that the addition of Fe0 and Achromobacter denitricans strain 2-5 could improve the removal efficiency of NH4+-N and TN in the SBR reactor. Compared with the ordinary SBR reactors, the average removal rates of NH4+-N and TN were increased by 4.13% and 15.73%. Through high-throughput sequencing analysis, differences were found in the composition of microbial community structure in each reactor. At the phylum level, Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes were the dominant phyla. The addition of Fe0 and Achromobacter denitrificans strain 2-5 increased the diversity of bacteria with aerobic denitrification function in the reactor and strengthened the denitrification effect of the SBR reactor. The research results provide a theoretical basis for Fe0 to promote the metabolic growth of aerobic denitrifying bacteria and are conducive to the practical application of aerobic denitrifying bacteria.
2022, 40(12): 217-223.
doi: 10.13205/j.hjgc.202212029
Abstract:
Treatment of heavy metal pollution in urban ecological environment becomes an urgent environmental problem. In order to explore the difference of remediation effect of heavy metal pollution in urban green space under different management measures, experimental plots with different management methods were established as the research object, and soil samples were collected to determine the contents of Cr, Ni, Cu, Zn, As, Cd and Pb in soil. The quantitative analysis of soil heavy metal pollution and ecological risk under different management methods by combining the single factor pollution index method, the Nemerow comprehensive pollution index, the geo-accumulation index method and the potential ecological risk assessment method. The results showed: 1) the contents of Cr, Ni, Cu, Zn, As, Cd and Pb in soil under different management methods were higher than the background value of Shaanxi Province. The contents of heavy metals in soil under different management methods were in an order of natural growth > irrigation > fertilization; 2) the variation trend of heavy metal content with the increase of soil depth was gradually decreasing, or first decreasing and then increasing, and the minimum value was obtained at the depth of 20 to 40 cm; 3) Cd was the main element causing ecological risk in the region, which is in light pollution state but with highest pollution level. Irrigation and fertilization have better remediation effect on soil heavy metal pollution than natural growth. Reasonable layout of urban green space management measures is conducive to the remediation of soil heavy metal pollution in urban green space and improvement of urban ecological environment quality.
Treatment of heavy metal pollution in urban ecological environment becomes an urgent environmental problem. In order to explore the difference of remediation effect of heavy metal pollution in urban green space under different management measures, experimental plots with different management methods were established as the research object, and soil samples were collected to determine the contents of Cr, Ni, Cu, Zn, As, Cd and Pb in soil. The quantitative analysis of soil heavy metal pollution and ecological risk under different management methods by combining the single factor pollution index method, the Nemerow comprehensive pollution index, the geo-accumulation index method and the potential ecological risk assessment method. The results showed: 1) the contents of Cr, Ni, Cu, Zn, As, Cd and Pb in soil under different management methods were higher than the background value of Shaanxi Province. The contents of heavy metals in soil under different management methods were in an order of natural growth > irrigation > fertilization; 2) the variation trend of heavy metal content with the increase of soil depth was gradually decreasing, or first decreasing and then increasing, and the minimum value was obtained at the depth of 20 to 40 cm; 3) Cd was the main element causing ecological risk in the region, which is in light pollution state but with highest pollution level. Irrigation and fertilization have better remediation effect on soil heavy metal pollution than natural growth. Reasonable layout of urban green space management measures is conducive to the remediation of soil heavy metal pollution in urban green space and improvement of urban ecological environment quality.
2022, 40(12): 224-230.
doi: 10.13205/j.hjgc.202212030
Abstract:
Environmental technology verification (ETV) is one of the effective evaluation methods for new environmental technology. It is a development trend of air pollution control in key industries by adopting ultra-low emission technologies. The research on ultra-low emission technologies verification of coal-fired power plants is an innovation in the refined application of environmental technology verification in the industry. In this study, based on analyzing the characteristics of air pollutants ultra-low emission technologies for coal-fired power plants, the verification index system of ultra-low emission technology for the coal-fired power plants was constructed by using an analytic hierarchy process, investigation and research methods, etc., and the acquisition method of verification index, test cycle and sample size, sampling frequency as well as index evaluation method were proposed. The application verification was carried out by taking an ultra-low emission combined technology, SCR denitration+dry electrostatic precipitation+limestone-gypsum wet desulfurization+wet electrostatic precipitation, as the example. The results showed that the technology verification method could objectively, scientifically, and effectively reflect the real performance of the technology on aspects of economy, environmental impact, maintenance and management, etc.
Environmental technology verification (ETV) is one of the effective evaluation methods for new environmental technology. It is a development trend of air pollution control in key industries by adopting ultra-low emission technologies. The research on ultra-low emission technologies verification of coal-fired power plants is an innovation in the refined application of environmental technology verification in the industry. In this study, based on analyzing the characteristics of air pollutants ultra-low emission technologies for coal-fired power plants, the verification index system of ultra-low emission technology for the coal-fired power plants was constructed by using an analytic hierarchy process, investigation and research methods, etc., and the acquisition method of verification index, test cycle and sample size, sampling frequency as well as index evaluation method were proposed. The application verification was carried out by taking an ultra-low emission combined technology, SCR denitration+dry electrostatic precipitation+limestone-gypsum wet desulfurization+wet electrostatic precipitation, as the example. The results showed that the technology verification method could objectively, scientifically, and effectively reflect the real performance of the technology on aspects of economy, environmental impact, maintenance and management, etc.
2022, 40(12): 231-238.
doi: 10.13205/j.hjgc.202212031
Abstract:
In order to improve the efficiency of VOCs source apportionment work, a PBP model based on BP neural network was proposed, which could analyze VOCs monitoring data in real time. The model was validated with the test dataset, and the results showed that it had the same accuracy as PMF model. Besides, it had the advantages of no limitation from the volume of data and fast computing speed. The PBP model was applied to the hourly resolution online VOCs dataset of an industrial zone in the Yangtze River Delta for 10 months, and the hourly resolution source apportionment results were obtained. The main sources of VOCs at the monitoring site were in the sequence of industrial process source (25%)>coal combustion source (20%)>gasoline vehicle exhaust source (18%)>solvent use source (15%)>mixed diesel vehicle and vessel exhaust source (12%)>fuel volatilization source (6%)>biogenic source (5%). Combined with the wind speed and direction data, the main emission directions of each source were identified, which provided a scientific basis for precise manage and control of VOCs sources. Therefore, it had a strong application potential in source apportionment.
In order to improve the efficiency of VOCs source apportionment work, a PBP model based on BP neural network was proposed, which could analyze VOCs monitoring data in real time. The model was validated with the test dataset, and the results showed that it had the same accuracy as PMF model. Besides, it had the advantages of no limitation from the volume of data and fast computing speed. The PBP model was applied to the hourly resolution online VOCs dataset of an industrial zone in the Yangtze River Delta for 10 months, and the hourly resolution source apportionment results were obtained. The main sources of VOCs at the monitoring site were in the sequence of industrial process source (25%)>coal combustion source (20%)>gasoline vehicle exhaust source (18%)>solvent use source (15%)>mixed diesel vehicle and vessel exhaust source (12%)>fuel volatilization source (6%)>biogenic source (5%). Combined with the wind speed and direction data, the main emission directions of each source were identified, which provided a scientific basis for precise manage and control of VOCs sources. Therefore, it had a strong application potential in source apportionment.
2022, 40(12): 239-243,223.
doi: 10.13205/j.hjgc.202212032
Abstract:
Based on the combination of online monitoring and artificial water quality, this paper formulated a systematic monitoring scheme through collecting background data, and realized the quantitative analysis of pollutants load in the region. The results showed that in the "squeezing out water" working part of improving quality and efficiency strategy, the removal of groundwater infiltrated by sewage pipelines can increase the water quality concentration of sewage plants by 36.01%, playing an important role; the contribution rate of pollutant load of sewage from industrial enterprises was low, and some enterprises needed to continue to discharge into the sewage treatment plant after pretreatment; in the "sewage collection" working part, the scattered sewage in the urban-rural fringe areas had a great impact on the increase of water plants’ inlet concentration. After all the sewage is collected in pipes, the pollutants’ concentration of the sewage plant inlet will increase by 30.30%. At the same time, although the mixed flow sewage of rainwater pipe network and the leakage sewage of river crossing pipeline have little impact on the increase of the inlet pollutants concentration of sewage plant, the pipe still needs to be modified and even reconstructed.
Based on the combination of online monitoring and artificial water quality, this paper formulated a systematic monitoring scheme through collecting background data, and realized the quantitative analysis of pollutants load in the region. The results showed that in the "squeezing out water" working part of improving quality and efficiency strategy, the removal of groundwater infiltrated by sewage pipelines can increase the water quality concentration of sewage plants by 36.01%, playing an important role; the contribution rate of pollutant load of sewage from industrial enterprises was low, and some enterprises needed to continue to discharge into the sewage treatment plant after pretreatment; in the "sewage collection" working part, the scattered sewage in the urban-rural fringe areas had a great impact on the increase of water plants’ inlet concentration. After all the sewage is collected in pipes, the pollutants’ concentration of the sewage plant inlet will increase by 30.30%. At the same time, although the mixed flow sewage of rainwater pipe network and the leakage sewage of river crossing pipeline have little impact on the increase of the inlet pollutants concentration of sewage plant, the pipe still needs to be modified and even reconstructed.
2022, 40(12): 244-252.
doi: 10.13205/j.hjgc.202212033
Abstract:
In this paper, hazard evaluation technology and technical process of remedial reagents applied in contaminated sites was explored and established, based on the requirements of the relevant laws and domestic regulations on soil pollution prevention and chemical management, in which physical, health and environmental hazards of the remedial reagents were mainly taken into account. The evaluation process mainly consisted of judgment and management of new chemicals, and identification of hazardous chemicals, and discrimination of their hazardous characteristics. Furthermore, remediation technology and remedial reagents for polluted soil and groundwater in contaminated sites in Shanghai were studied to verify the established technical process. Basic information on 135 contaminated site remediation projects in Shanghai was collected, and the remediation technologies and remedial reagents for typical contaminants were summarized. Hazardous characteristics of the remedial agents were then identified. For example, hydrogen peroxide, a conventional oxidant, could cause combustion or explosion if in high concentration, so a concentration of 60% below was advised. This study would provide innovative ideas, basic data, and technical support for the safe implementation of contaminated site remediation projects, safe use of remedial agents and soil remediation supervision by the ecological environment authorities in China.
In this paper, hazard evaluation technology and technical process of remedial reagents applied in contaminated sites was explored and established, based on the requirements of the relevant laws and domestic regulations on soil pollution prevention and chemical management, in which physical, health and environmental hazards of the remedial reagents were mainly taken into account. The evaluation process mainly consisted of judgment and management of new chemicals, and identification of hazardous chemicals, and discrimination of their hazardous characteristics. Furthermore, remediation technology and remedial reagents for polluted soil and groundwater in contaminated sites in Shanghai were studied to verify the established technical process. Basic information on 135 contaminated site remediation projects in Shanghai was collected, and the remediation technologies and remedial reagents for typical contaminants were summarized. Hazardous characteristics of the remedial agents were then identified. For example, hydrogen peroxide, a conventional oxidant, could cause combustion or explosion if in high concentration, so a concentration of 60% below was advised. This study would provide innovative ideas, basic data, and technical support for the safe implementation of contaminated site remediation projects, safe use of remedial agents and soil remediation supervision by the ecological environment authorities in China.
2022, 40(12): 253-269.
doi: 10.13205/j.hjgc.202212034
Abstract:
Organic contaminants in water/wastewater could cause damage to the ecosystem and human health due to their toxicity, persistence and bio-refractory nature. The membrane-based separation processes separate contaminants from water by physicochemical mechanisms. However, the interactions of organic molecules, and microorganisms with membrane surfaces inevitably lead to membrane fouling, which shortens membrane lifetime. Electrochemical membrane filtration (EMF) is an emerging water treatment technology that integrates the dual functions of contaminant retention and electrochemical degradation. It has the advantages of enhanced contaminant removal, antifouling and improved performance, which has received extensive research attention in the areas of advanced contaminant removal and disinfection. This paper reviews the research progress of electrochemical membrane filtration for water treatment in recent years, and introduces the principles of operation and advantages. The electrochemical membrane materials, reactor operating parameters, the influence of water quality parameters and the applications of EMF in pollutant removal and water disinfection are also summarized. Finally, the future development and perspectives of EMF are proposed.
Organic contaminants in water/wastewater could cause damage to the ecosystem and human health due to their toxicity, persistence and bio-refractory nature. The membrane-based separation processes separate contaminants from water by physicochemical mechanisms. However, the interactions of organic molecules, and microorganisms with membrane surfaces inevitably lead to membrane fouling, which shortens membrane lifetime. Electrochemical membrane filtration (EMF) is an emerging water treatment technology that integrates the dual functions of contaminant retention and electrochemical degradation. It has the advantages of enhanced contaminant removal, antifouling and improved performance, which has received extensive research attention in the areas of advanced contaminant removal and disinfection. This paper reviews the research progress of electrochemical membrane filtration for water treatment in recent years, and introduces the principles of operation and advantages. The electrochemical membrane materials, reactor operating parameters, the influence of water quality parameters and the applications of EMF in pollutant removal and water disinfection are also summarized. Finally, the future development and perspectives of EMF are proposed.
2022, 40(12): 270-280.
doi: 10.13205/j.hjgc.202212035
Abstract:
Antibiotic contamination and the resulting resistance genes have attracted worldwide attention because of the extensive overuse and abuse of antibiotics, which seriously affects the environment as well as human health. This paper summarizes the latest progress in the removal of antibiotics and resistance genes from wastewater by constructed wetlands. Many studies showed that the removal rate of antibiotics in sewage by constructed wetland is generally 60% to 100%, and the removal rate of antibiotic resistance genes is generally 10% to 100%. The main influence factors of the removal of antibiotics and resistance genes in constructed wetland include seasonal variation, influent quality, hydraulic retention time, temperature, pH, microorganism, plant and substrate. The constructed wetlands incorporate biodegradation, adsorption, plant uptake, hydrolysis, and photodecomposition for antibiotics and antibiotic resistance genes. Although constructed wetland can remove antibiotics and resistance genes, the enrichment of antibiotics in the substrate and the increase of the abundance of effluent resistance genes will bring potential risks, which should be paid attention to. Further study should focus on the synergistic removal mechanism of antibiotics, resistance genes and traditional pollutants by constructed wetland, the removal mechanism and contribution of every part of constructed wetlands, as well as the newly constructed wetland treatment technologies coupled with bioelectrochemical systems.
Antibiotic contamination and the resulting resistance genes have attracted worldwide attention because of the extensive overuse and abuse of antibiotics, which seriously affects the environment as well as human health. This paper summarizes the latest progress in the removal of antibiotics and resistance genes from wastewater by constructed wetlands. Many studies showed that the removal rate of antibiotics in sewage by constructed wetland is generally 60% to 100%, and the removal rate of antibiotic resistance genes is generally 10% to 100%. The main influence factors of the removal of antibiotics and resistance genes in constructed wetland include seasonal variation, influent quality, hydraulic retention time, temperature, pH, microorganism, plant and substrate. The constructed wetlands incorporate biodegradation, adsorption, plant uptake, hydrolysis, and photodecomposition for antibiotics and antibiotic resistance genes. Although constructed wetland can remove antibiotics and resistance genes, the enrichment of antibiotics in the substrate and the increase of the abundance of effluent resistance genes will bring potential risks, which should be paid attention to. Further study should focus on the synergistic removal mechanism of antibiotics, resistance genes and traditional pollutants by constructed wetland, the removal mechanism and contribution of every part of constructed wetlands, as well as the newly constructed wetland treatment technologies coupled with bioelectrochemical systems.
