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2021 Vol. 39, No. 10
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2021, 39(10): 1-7.
doi: 10.13205/j.hjgc.202110001
Abstract:
Based on mathematical statistics methods of Bootstrap sampling, we constructed an Evaluation model on the Status of CO2 emissions (ESC). This paper selected the areas with a good statistical basis, used multi-source time series data from the authorities, and combined with the emission uncertainty by referring to the IPCC Guidelines for national greenhouse gas inventories to explore the CO2 emission distribution and statistical parameters, which included the standard deviation and uncertainty of the emission. The statistical parameters were used as a quantitative criterion to determine the peak, plateau, and decline period of CO2 emission and solve the calculation errors caused by statistical accounting. Based on the ESC model, the peak period was within 1% (0.9%~1.1%) of peak CO2 emission. The plateau and decline period were evaluated based on the comparison between the annual decline rate and 2% (1.8%~2.2%). Once the annual decline rate after the CO2 emission peak exceeded 2%, we assumed the CO2 emission to be the decline period, otherwise the plateau period. Besides, we applied the ESC model to evaluate the periods of historical CO2 emission for the European Union and the United States. The results showed that:the European Union reached the CO2 emission peak in 1979, then entered the decline period from 1980 to 1983; the United States reached the CO2 emission peak in 2007, then entered the decline period of CO2 emission from 2008 to 2012; our model was reasonable on quantitative evaluation on the status of CO2 emission peak. This study could provide reference value for quantitative evaluation on the status of CO2 emission (including the peak, plateau, and decline period) for the country, region (province), or the city, provide sound support for studies on the pathway analysis and scenario simulation of CO2 emission, and offer scientific evaluation reference for decision makers.
Based on mathematical statistics methods of Bootstrap sampling, we constructed an Evaluation model on the Status of CO2 emissions (ESC). This paper selected the areas with a good statistical basis, used multi-source time series data from the authorities, and combined with the emission uncertainty by referring to the IPCC Guidelines for national greenhouse gas inventories to explore the CO2 emission distribution and statistical parameters, which included the standard deviation and uncertainty of the emission. The statistical parameters were used as a quantitative criterion to determine the peak, plateau, and decline period of CO2 emission and solve the calculation errors caused by statistical accounting. Based on the ESC model, the peak period was within 1% (0.9%~1.1%) of peak CO2 emission. The plateau and decline period were evaluated based on the comparison between the annual decline rate and 2% (1.8%~2.2%). Once the annual decline rate after the CO2 emission peak exceeded 2%, we assumed the CO2 emission to be the decline period, otherwise the plateau period. Besides, we applied the ESC model to evaluate the periods of historical CO2 emission for the European Union and the United States. The results showed that:the European Union reached the CO2 emission peak in 1979, then entered the decline period from 1980 to 1983; the United States reached the CO2 emission peak in 2007, then entered the decline period of CO2 emission from 2008 to 2012; our model was reasonable on quantitative evaluation on the status of CO2 emission peak. This study could provide reference value for quantitative evaluation on the status of CO2 emission (including the peak, plateau, and decline period) for the country, region (province), or the city, provide sound support for studies on the pathway analysis and scenario simulation of CO2 emission, and offer scientific evaluation reference for decision makers.
2021, 39(10): 8-14.
doi: 10.13205/j.hjgc.202110002
Abstract:
Under the background of the proposed Double Carbon goal, the power industry, as the primary carbon emission industry, will assume a greater share and responsibility of emission reduction. The paper selected 13 key low-carbon technology of power industry to evaluate and compare the trends of carbon abatement potential and corresponding cost during the process of peaking carbondioxide emissions. Taking every 5 years as a period, the marginal abatement cost curve (MACC) was analyzed, and the technology-based and cost-optimal carbon abatement plan for power industry in each selected year was offered. The results showed that the total carbon abatement potential of the 13 selected technologies in 2020, 2025, 2030 and 2035 were 470 million, 700 million, 500 million and 540 million tons, respectively. The corresponding average carbon abatement cost were 8,67,242,464 yuan/ton in each year. While, the marginal abatement cost of selected technologies in 2020 ranged from -295 yuan/ton to 376 yuan/ton. In terms of technology types, every technology showed specificity on the MACC. Compared with system flexibility and technology upgrading, power structure optimization had higher carbon abatement potential and lower carbon abatement cost. This paper can provide data support to select the low-carbon technology-based and cost-optimal plan in the power industry.
Under the background of the proposed Double Carbon goal, the power industry, as the primary carbon emission industry, will assume a greater share and responsibility of emission reduction. The paper selected 13 key low-carbon technology of power industry to evaluate and compare the trends of carbon abatement potential and corresponding cost during the process of peaking carbondioxide emissions. Taking every 5 years as a period, the marginal abatement cost curve (MACC) was analyzed, and the technology-based and cost-optimal carbon abatement plan for power industry in each selected year was offered. The results showed that the total carbon abatement potential of the 13 selected technologies in 2020, 2025, 2030 and 2035 were 470 million, 700 million, 500 million and 540 million tons, respectively. The corresponding average carbon abatement cost were 8,67,242,464 yuan/ton in each year. While, the marginal abatement cost of selected technologies in 2020 ranged from -295 yuan/ton to 376 yuan/ton. In terms of technology types, every technology showed specificity on the MACC. Compared with system flexibility and technology upgrading, power structure optimization had higher carbon abatement potential and lower carbon abatement cost. This paper can provide data support to select the low-carbon technology-based and cost-optimal plan in the power industry.
2021, 39(10): 15-22.
doi: 10.13205/j.hjgc.202110003
Abstract:
In order to reduce the carbon emission abatement cost of cement industry and determine the optimal carbon emission reduction technology path, based on the economic-energy model, we calculated the marginal abatement cost of the latest carbon emission reduction technology in China's cement industry in this paper. Using scenario analysis method to study the future emission reduction potential of 17 technologies implemented in 2020, compared with the non-implemented technologies, we took them as the benchmark scenario and compare them to carbon emission reduction potentials of the three future scenarios in 2025, 2030 and 2035 to obtain the different marginal emission reduction cost curves. The results showed that:1) the average abatement cost of 17 technologies in China's cement industry was 124 yuan/tCO2 in 2020. The total emission reduction was 30.4 million tons in 2020, and the total abatement cost was 1.03 billion yuan; for maintaining the same level of technology and emission, in 2035, the total emission reduction of 17 technologies will be 213.07 million tons, and the total abatement cost will be 10.34 billion yuan. 2) among the emission abatement technologies, the energy saving technology of integrated modular kiln lining and optimization technology of cement clinker firing system had higher emission reduction potential and lower abatement cost. Although carbon capture, use and storage technology had higher abatement cost, it had greater potential for future emission reductions. 3) technology penetration rate and clinker outputs were important factors in determining emission reduction potential. Therefore, in the future, the cement industry should pay attention to energy conservation and emission reduction policies, technology promotion and industrial structure adjustment, so as to further achieve the emission reduction target.
In order to reduce the carbon emission abatement cost of cement industry and determine the optimal carbon emission reduction technology path, based on the economic-energy model, we calculated the marginal abatement cost of the latest carbon emission reduction technology in China's cement industry in this paper. Using scenario analysis method to study the future emission reduction potential of 17 technologies implemented in 2020, compared with the non-implemented technologies, we took them as the benchmark scenario and compare them to carbon emission reduction potentials of the three future scenarios in 2025, 2030 and 2035 to obtain the different marginal emission reduction cost curves. The results showed that:1) the average abatement cost of 17 technologies in China's cement industry was 124 yuan/tCO2 in 2020. The total emission reduction was 30.4 million tons in 2020, and the total abatement cost was 1.03 billion yuan; for maintaining the same level of technology and emission, in 2035, the total emission reduction of 17 technologies will be 213.07 million tons, and the total abatement cost will be 10.34 billion yuan. 2) among the emission abatement technologies, the energy saving technology of integrated modular kiln lining and optimization technology of cement clinker firing system had higher emission reduction potential and lower abatement cost. Although carbon capture, use and storage technology had higher abatement cost, it had greater potential for future emission reductions. 3) technology penetration rate and clinker outputs were important factors in determining emission reduction potential. Therefore, in the future, the cement industry should pay attention to energy conservation and emission reduction policies, technology promotion and industrial structure adjustment, so as to further achieve the emission reduction target.
2021, 39(10): 23-31,40.
doi: 10.13205/j.hjgc.202110004
Abstract:
Promoting the low-carbon development of the iron and steel industry has become an important part of achieving carbon peaking and carbon neutrality in China, as it's a major energy consumption and CO2 emitting industry. In this paper, we analyzed the key abatement technologies and the abatement costs for iron and steel industry under three types of scenarios and four decarbonization aspects:energy structure adjustment, process structure optimization, energy saving and emission reduction technology promotion, and CCUS technology application, to reveal the emission reduction priority of each technology. The results indicated that, under the steady development scenario, the average abatement cost for iron and steel industry was RMB 433/t CO2. The total abatement cost of all the technologies was RMB 210 billion, with a total carbon abatement volume of 490 million tons. Among the various abatement technologies, scrap-EAF had the best economic efficiency, contributing nearly half of the total abatement in the iron and steel industry, indicating that the scarp-EAF becomes an essential measure for China's iron and steel industry to achieve the target of carbon peak and carbon neutrality.
Promoting the low-carbon development of the iron and steel industry has become an important part of achieving carbon peaking and carbon neutrality in China, as it's a major energy consumption and CO2 emitting industry. In this paper, we analyzed the key abatement technologies and the abatement costs for iron and steel industry under three types of scenarios and four decarbonization aspects:energy structure adjustment, process structure optimization, energy saving and emission reduction technology promotion, and CCUS technology application, to reveal the emission reduction priority of each technology. The results indicated that, under the steady development scenario, the average abatement cost for iron and steel industry was RMB 433/t CO2. The total abatement cost of all the technologies was RMB 210 billion, with a total carbon abatement volume of 490 million tons. Among the various abatement technologies, scrap-EAF had the best economic efficiency, contributing nearly half of the total abatement in the iron and steel industry, indicating that the scarp-EAF becomes an essential measure for China's iron and steel industry to achieve the target of carbon peak and carbon neutrality.
2021, 39(10): 32-40.
doi: 10.13205/j.hjgc.202110005
Abstract:
Petrochemical and chemical industries are the pillar industries of China's national economy, as well as the industries with high energy consumption and emission. To achieve their low-carbon development, it's the key to balance the relationship between industry self-development and the goal of decarbonization. In this paper, we analyzed the key abatement technologies and the abatement costs for petrochemical and chemical industries through the expert-based and model-derived marginal abatement cost curve. The results indicated that the average abatement cost of petrochemical and chemical industries was RMB 298/t, with the potential of contributing the abatement of 0.44 billion tons CO2 in 2035 (account for 30% of total carbon emissions). Compared with energy conservation technologies, energy substitution have higher abatement cost, but also have higher abatement potential. In 2035, the application of energy substitution will account for 62% of the total carbon emission abatement. In this case, promoting the transformation of coal to renewable, clean energy will be the key to achieve carbon neutrality in the petrochemical and chemical industries.
Petrochemical and chemical industries are the pillar industries of China's national economy, as well as the industries with high energy consumption and emission. To achieve their low-carbon development, it's the key to balance the relationship between industry self-development and the goal of decarbonization. In this paper, we analyzed the key abatement technologies and the abatement costs for petrochemical and chemical industries through the expert-based and model-derived marginal abatement cost curve. The results indicated that the average abatement cost of petrochemical and chemical industries was RMB 298/t, with the potential of contributing the abatement of 0.44 billion tons CO2 in 2035 (account for 30% of total carbon emissions). Compared with energy conservation technologies, energy substitution have higher abatement cost, but also have higher abatement potential. In 2035, the application of energy substitution will account for 62% of the total carbon emission abatement. In this case, promoting the transformation of coal to renewable, clean energy will be the key to achieve carbon neutrality in the petrochemical and chemical industries.
2021, 39(10): 50-56,63.
doi: 10.13205/j.hjgc.202110007
Abstract:
As an important source of carbon emissions in the transportation sector, road transportation will take on important responsibilities in the process of achieving the goal of Carbon Peak and Carbon Neutrality. Research on the cost of carbon emission reduction technologies is conducive to balancing the development of road traffic motorization and the realization of this goal, which is an important measure to realize the sustainable development of road transport. This research divided vehicles into passenger cars, commercial buses, light commercial trucks and heavy commercial trucks, and then analyzed reduction potential and cost of the engine technology, transmission technology, auxiliary system technology, vehicle technology and new energy vehicle applications on these vehicles, and finally established the MAC curve of my country's road transport carbon emissions from 2020 to 2035. The main conclusions are as follows:1) the same vehicle energy saving and emission reduction technology had the lowest unit carbon emissions abatement cost when applied to heavy commercial truck. Meanwhile, the application of new energy vehicles in passenger cars had great potential for emission reduction, but it did not occupy a cost advantage compared with other models. 2)the unit carbon emissions abatement cost of fuel cell new energy vehicles was much higher than that of pure electric and plug-in hybrid new energy vehicles. In the future, it was necessary to reduce the production cost of fuel cells and the cost of hydrogen preparation, storage and transportation. 3) the total carbon emissions abatement costs first increased and then decreased, which indicated that with the reasonable promotion of energy-saving emission reduction technologies, the resistance to emission reduction in this sector was declining.
As an important source of carbon emissions in the transportation sector, road transportation will take on important responsibilities in the process of achieving the goal of Carbon Peak and Carbon Neutrality. Research on the cost of carbon emission reduction technologies is conducive to balancing the development of road traffic motorization and the realization of this goal, which is an important measure to realize the sustainable development of road transport. This research divided vehicles into passenger cars, commercial buses, light commercial trucks and heavy commercial trucks, and then analyzed reduction potential and cost of the engine technology, transmission technology, auxiliary system technology, vehicle technology and new energy vehicle applications on these vehicles, and finally established the MAC curve of my country's road transport carbon emissions from 2020 to 2035. The main conclusions are as follows:1) the same vehicle energy saving and emission reduction technology had the lowest unit carbon emissions abatement cost when applied to heavy commercial truck. Meanwhile, the application of new energy vehicles in passenger cars had great potential for emission reduction, but it did not occupy a cost advantage compared with other models. 2)the unit carbon emissions abatement cost of fuel cell new energy vehicles was much higher than that of pure electric and plug-in hybrid new energy vehicles. In the future, it was necessary to reduce the production cost of fuel cells and the cost of hydrogen preparation, storage and transportation. 3) the total carbon emissions abatement costs first increased and then decreased, which indicated that with the reasonable promotion of energy-saving emission reduction technologies, the resistance to emission reduction in this sector was declining.
2021, 39(10): 57-63.
doi: 10.13205/j.hjgc.202110008
Abstract:
Chlorine dioxide is a kind of disinfectant with excellent performance and wide application. Chlorine dioxide disinfects microbe by means of damaging the structure of cells and viruses and inhibiting cell metabolism. Calculated by multiplying chlorine dioxide dosage by the contact time, chlorine dioxide was able to inactivate many common viruses (for example, Enterovirus 71, coliphage MS2, etc.) for more than 3log inactivation rate with a dose of 15 (mg·min)/L, and effectively inactivate bacteria (for example, Escherichia coli, Staphylococcus aureus, etc.) for more than 1.5 log with a dose of 60 (mg·min)/L; however, more doses of chlorine dioxide were needed to achieve efficacious disinfection of Cryptosporidium parvum oocysts (for instance, achieving 1.9 log inactivation rate with about 600 (mg·min)/L dose); in wastewater treatment plant (WWTP) influent, only 0.8 log of Escherichia coli and 0.5 log of total coliform inactivation rate were achieved with 30 (mg·min)/L chlorine dioxide dose. The efficiency of chlorine dioxide inactivation was improved as the temperature rise, but the impact of pH for chlorine dioxide inactivation efficiency of different microbe may be different. Usually, organic matter in water samples weakened chlorine dioxide effect for disinfection by consuming chlorine dioxide. However, there were exceptions in natural waters with better inactivation efficiency than that in pure water which may result from the influence of natural organic matter. Research on microbial community structure after chlorine dioxide disinfection was insufficient with only a few studies concerning municipal sewage, reclaimed water and drinking water, etc. In a certain time after chlorine dioxide disinfection, both suspended and attached microbe may regrow, but changes of microbial community structure and secretion characteristics still remained to be studied.
Chlorine dioxide is a kind of disinfectant with excellent performance and wide application. Chlorine dioxide disinfects microbe by means of damaging the structure of cells and viruses and inhibiting cell metabolism. Calculated by multiplying chlorine dioxide dosage by the contact time, chlorine dioxide was able to inactivate many common viruses (for example, Enterovirus 71, coliphage MS2, etc.) for more than 3log inactivation rate with a dose of 15 (mg·min)/L, and effectively inactivate bacteria (for example, Escherichia coli, Staphylococcus aureus, etc.) for more than 1.5 log with a dose of 60 (mg·min)/L; however, more doses of chlorine dioxide were needed to achieve efficacious disinfection of Cryptosporidium parvum oocysts (for instance, achieving 1.9 log inactivation rate with about 600 (mg·min)/L dose); in wastewater treatment plant (WWTP) influent, only 0.8 log of Escherichia coli and 0.5 log of total coliform inactivation rate were achieved with 30 (mg·min)/L chlorine dioxide dose. The efficiency of chlorine dioxide inactivation was improved as the temperature rise, but the impact of pH for chlorine dioxide inactivation efficiency of different microbe may be different. Usually, organic matter in water samples weakened chlorine dioxide effect for disinfection by consuming chlorine dioxide. However, there were exceptions in natural waters with better inactivation efficiency than that in pure water which may result from the influence of natural organic matter. Research on microbial community structure after chlorine dioxide disinfection was insufficient with only a few studies concerning municipal sewage, reclaimed water and drinking water, etc. In a certain time after chlorine dioxide disinfection, both suspended and attached microbe may regrow, but changes of microbial community structure and secretion characteristics still remained to be studied.
2021, 39(10): 64-71,128.
doi: 10.13205/j.hjgc.202110009
Abstract:
Taking Poyang Lake, a large river-connected lake in China as an example, 10 indicators, including Chl-a and TN, were measured at six typical points in Poyang Lake from 2016 to 2018. The spatio-temporal variation characteristics of different factors in Poyang Lake were analyzed, and the driving factors of algal proliferation were determined by integrated trophic state index method and principal component analysis, combined with the hydrology and hydrodynamics, sediment and anthropogenic influence of Poyang Lake. The results showed that:COD concentration was higher in the south and lower in the north, showed a high-low-high trend from the west to the east. The trend of TN concentration was similar to that of NH3-N, showing higher in the south and the east, and lower in the north in summer, while the distribution spread from Banghu to Duchang in the west. TP concentration was higher in the south and lower in the north, and high in both the east and west. The occurrence frequency of Melosira and Microcystis was 51.11% and 16.44%, respectively. The density of algal cells and chl-a were the highest in Banghu, which were 7.8 and 5.3 times higher than those in Hukou, respectively. Poyang Lake was mainly at a light eutrophication level during the study period. TP was the main limiting factor for algal proliferation at six sites, which had little relationship with TN. Also, water temperature and dissolved oxygen may be factors for algal proliferation in Poyang Lake. In the future, the comprehensive management of algae in Poyang Lake should be carried out by strengthening seasonal monitoring and early warning, focusing on identifying and regulating key factors at measurement points, and strengthening algal species monitoring.
Taking Poyang Lake, a large river-connected lake in China as an example, 10 indicators, including Chl-a and TN, were measured at six typical points in Poyang Lake from 2016 to 2018. The spatio-temporal variation characteristics of different factors in Poyang Lake were analyzed, and the driving factors of algal proliferation were determined by integrated trophic state index method and principal component analysis, combined with the hydrology and hydrodynamics, sediment and anthropogenic influence of Poyang Lake. The results showed that:COD concentration was higher in the south and lower in the north, showed a high-low-high trend from the west to the east. The trend of TN concentration was similar to that of NH3-N, showing higher in the south and the east, and lower in the north in summer, while the distribution spread from Banghu to Duchang in the west. TP concentration was higher in the south and lower in the north, and high in both the east and west. The occurrence frequency of Melosira and Microcystis was 51.11% and 16.44%, respectively. The density of algal cells and chl-a were the highest in Banghu, which were 7.8 and 5.3 times higher than those in Hukou, respectively. Poyang Lake was mainly at a light eutrophication level during the study period. TP was the main limiting factor for algal proliferation at six sites, which had little relationship with TN. Also, water temperature and dissolved oxygen may be factors for algal proliferation in Poyang Lake. In the future, the comprehensive management of algae in Poyang Lake should be carried out by strengthening seasonal monitoring and early warning, focusing on identifying and regulating key factors at measurement points, and strengthening algal species monitoring.
2021, 39(10): 72-77.
doi: 10.13205/j.hjgc.202110010
Abstract:
In order to optimize the ozone dosage in an up flow activated carbon-ultrafiltration combined process for the water works, pilot-scale experiments were conducted to study the impact of ozone dosages on the processing efficiency of each unit, and the central composite response surface design was adopted to study the effect of ozone dosage on TOC and trihalomethane formation potential (THMFP), meanwhile, the removal efficiency of typical odor compounds and antibiotics in Jinze Reservoir was also analyzed. The results showed that excessively high pre-ozone dosage was not conducive to the removal of turbidity, UV254 and CODMn in the coagulatory settler, while exceedingly high post-ozone dosage was not conducive to the removal of UV254 and CODMn in the activated carbon filter. For the removal of TOC and THMFP in Jinze Reservoir, the optimized ozone dosage range was 0.6~0.65 mg/L and 1.35~1.4 mg/L for the pre-ozone and post-ozone dosage, respectively. Moreover, the pilot-scale process was highly effective in removing typical antibiotics and odor compounds except 1,4-dichlorobenzene and ethylbenzene in Jinze reservoir.
In order to optimize the ozone dosage in an up flow activated carbon-ultrafiltration combined process for the water works, pilot-scale experiments were conducted to study the impact of ozone dosages on the processing efficiency of each unit, and the central composite response surface design was adopted to study the effect of ozone dosage on TOC and trihalomethane formation potential (THMFP), meanwhile, the removal efficiency of typical odor compounds and antibiotics in Jinze Reservoir was also analyzed. The results showed that excessively high pre-ozone dosage was not conducive to the removal of turbidity, UV254 and CODMn in the coagulatory settler, while exceedingly high post-ozone dosage was not conducive to the removal of UV254 and CODMn in the activated carbon filter. For the removal of TOC and THMFP in Jinze Reservoir, the optimized ozone dosage range was 0.6~0.65 mg/L and 1.35~1.4 mg/L for the pre-ozone and post-ozone dosage, respectively. Moreover, the pilot-scale process was highly effective in removing typical antibiotics and odor compounds except 1,4-dichlorobenzene and ethylbenzene in Jinze reservoir.
2021, 39(10): 78-84.
doi: 10.13205/j.hjgc.202110011
Abstract:
Iron and manganese are redox sensitive elements. Anaerobic and aerobic process can cause the release and morphological transformation of iron, manganese and sulfide sediments, resulting in the deterioration of water quality. At present, few studies combined black water of reservoir with migration of iron, manganese and sulfide. In order to explore the frequent blackening phenomenon of reservoirs in the southern water source area, we selected the Tianbao reservoir in Nanning as the research object, and collected samples from different depths of the reservoir from March 2018 to December 2018, to analyze the seasonal variation characteristics of water quality of the reservoir and the influence on the migration and transformation of iron, manganese and sulfide. The results showed that the thermal stratification structure was mainly affected by the temperature change. The formation of thermocline in stratification period led to the vertical physical and chemical properties difference, which formed the low temperature anaerobic environment at the bottom. And the unique red soil structure made iron and manganese have stronger endogenous release capacity. Under the influence of rainfall erosion and long-term anaerobic situation, the iron and manganese layer released in large quantities (0.76 mg/L and 1.47 mg/L), the sulfide release was inhibited by high concentration iron (0.005 mg/L). During the blackening period, the stratification failure caused vertical convective mixing. Reoxygenation transformed the forms of iron, manganese and sulfide, and simultaneously migration upward produced FES, MNS and other blackening substances, which triggered the surface blackening phenomenon. The key to solve the problem of blackening was to carry out researches on triggering mechanism and substance screening of black water.
Iron and manganese are redox sensitive elements. Anaerobic and aerobic process can cause the release and morphological transformation of iron, manganese and sulfide sediments, resulting in the deterioration of water quality. At present, few studies combined black water of reservoir with migration of iron, manganese and sulfide. In order to explore the frequent blackening phenomenon of reservoirs in the southern water source area, we selected the Tianbao reservoir in Nanning as the research object, and collected samples from different depths of the reservoir from March 2018 to December 2018, to analyze the seasonal variation characteristics of water quality of the reservoir and the influence on the migration and transformation of iron, manganese and sulfide. The results showed that the thermal stratification structure was mainly affected by the temperature change. The formation of thermocline in stratification period led to the vertical physical and chemical properties difference, which formed the low temperature anaerobic environment at the bottom. And the unique red soil structure made iron and manganese have stronger endogenous release capacity. Under the influence of rainfall erosion and long-term anaerobic situation, the iron and manganese layer released in large quantities (0.76 mg/L and 1.47 mg/L), the sulfide release was inhibited by high concentration iron (0.005 mg/L). During the blackening period, the stratification failure caused vertical convective mixing. Reoxygenation transformed the forms of iron, manganese and sulfide, and simultaneously migration upward produced FES, MNS and other blackening substances, which triggered the surface blackening phenomenon. The key to solve the problem of blackening was to carry out researches on triggering mechanism and substance screening of black water.
2021, 39(10): 85-92,109.
doi: 10.13205/j.hjgc.202110012
Abstract:
The selection of models is the key to the species-sensitive distribution method. In this study, characteristics and applicability of five distribution models commonly used in the species-sensitive distribution methods were systematically introduced, which were normal distribution, log-normal distribution, logistic distribution, log-logistic distribution and Burr-Ⅲ distribution. The variability among the models was analyzed. This study not only proposed the methods of model screening and goodness-of-fit test in species sensitivity distribution fitting, but also fitted the species sensitivity distribution curves of cadmium using each one of the five models, and further discussed the differences between the models and the basis of selection. Finally, some suggestions for model selection in the fitting of species-sensitivity distribution were presented. This result could provide theoretical references for the application of the species-sensitivity distribution method and the derivation of water quality benchmarks.
The selection of models is the key to the species-sensitive distribution method. In this study, characteristics and applicability of five distribution models commonly used in the species-sensitive distribution methods were systematically introduced, which were normal distribution, log-normal distribution, logistic distribution, log-logistic distribution and Burr-Ⅲ distribution. The variability among the models was analyzed. This study not only proposed the methods of model screening and goodness-of-fit test in species sensitivity distribution fitting, but also fitted the species sensitivity distribution curves of cadmium using each one of the five models, and further discussed the differences between the models and the basis of selection. Finally, some suggestions for model selection in the fitting of species-sensitivity distribution were presented. This result could provide theoretical references for the application of the species-sensitivity distribution method and the derivation of water quality benchmarks.
2021, 39(10): 93-100.
doi: 10.13205/j.hjgc.202110013
Abstract:
The forecast of PM2.5 concentration plays an important role in air pollution control and improvement of environmental quality. Affected by multiple factors such as changes in meteorological conditions and air pollutants emissions, the PM2.5 forecast was usually susceptible to sudden changes and noise data. Therefore, in-depth exploration of the PM2.5 concentration change law and modeling robust prediction models have become key steps in this task. Based on the analysis of the correlation between meteorological conditions and atmospheric pollutants on PM2.5, a staged temporal-attention network (STAN) was proposed. This method combined a multi-stage attention module and a recurrent neural network (RNN) to model the cross-influence of meteorological factors and atmospheric pollutants on PM2.5 concentration. Statistical analysis of the absolute error values of the prediction results of Beijing, Shanghai, and Guangzhou showed the following results:1) compared with the widely used support vector machine (SVM), long short-term memory (LSTM), and multilayer perceptron (MLP), the performance of the proposed method increased more than 10%. 2) compared with the latest fusion model U-net, the proposed STAN still achieved a decrease in the error of 7%. Taking Beijing's winter forecast results as an example for statistical analysis, the fitting coefficient between the predicted value of STAN and the measured value could reach 95.2%. In the robustness analysis, it was found that the error increased by only 9.3% when the proposed method ran on data with 10% noise. The above results proved that the combination of the attention mechanism and the temporal learning module could deeply mine the change law of PM2.5 and suppress noise data. It also showed that the STAN could achieve the robust prediction of PM2.5 concentration.
The forecast of PM2.5 concentration plays an important role in air pollution control and improvement of environmental quality. Affected by multiple factors such as changes in meteorological conditions and air pollutants emissions, the PM2.5 forecast was usually susceptible to sudden changes and noise data. Therefore, in-depth exploration of the PM2.5 concentration change law and modeling robust prediction models have become key steps in this task. Based on the analysis of the correlation between meteorological conditions and atmospheric pollutants on PM2.5, a staged temporal-attention network (STAN) was proposed. This method combined a multi-stage attention module and a recurrent neural network (RNN) to model the cross-influence of meteorological factors and atmospheric pollutants on PM2.5 concentration. Statistical analysis of the absolute error values of the prediction results of Beijing, Shanghai, and Guangzhou showed the following results:1) compared with the widely used support vector machine (SVM), long short-term memory (LSTM), and multilayer perceptron (MLP), the performance of the proposed method increased more than 10%. 2) compared with the latest fusion model U-net, the proposed STAN still achieved a decrease in the error of 7%. Taking Beijing's winter forecast results as an example for statistical analysis, the fitting coefficient between the predicted value of STAN and the measured value could reach 95.2%. In the robustness analysis, it was found that the error increased by only 9.3% when the proposed method ran on data with 10% noise. The above results proved that the combination of the attention mechanism and the temporal learning module could deeply mine the change law of PM2.5 and suppress noise data. It also showed that the STAN could achieve the robust prediction of PM2.5 concentration.
2021, 39(10): 101-109.
doi: 10.13205/j.hjgc.202110014
Abstract:
In practical engineering, because the exhaust hood was directly connected with the dust removal system, the size and flow of the exhaust hood were not easy to change once determined. When the actual exhaust air volume was much smaller than the exhaust air volume designed by the design method, it was difficult to obtain the optimal design parameters by using the traditional design method. Therefore, reasonable design of the size and flow of air supply outlet under the determined the form and flow of exhaust hood have strong practical significance. In this paper, numerical simulation was used to compare the flow field and the capture of pollutants under different forms of side suction exhaust hood and supply air device. On this basis, the air supply inlet were added, and the capture characteristics of different air supply flow rate on the pollutants were compared under the the constant exhaust flow. In addition, the effects of different air supply terminal devices on the capture of pollutants were studied. The results showed that movable exhaust hood and rotating open and closed exhaust hood could effectively improve the capture efficiency of pollutants. On this basis, the capture efficiency of pollutant could be improved by using air supply inlet, compared with using the exhaust hood alone. It was found that when the exhaust flow of the exhaust hood in the actual project was determined, the ratio of the exhaust flow should be adjusted on the premise that the supply air flow could effectively transport pollutants to the exhaust outlet. Finally, it was found that using parallel flow air supply device could improve the uniformity of air supply, improve the capture efficiency of exhaust hood. The results of the present study could provide certain guidance for the transformation and design of the push pull ventilation device in practical engineering.
In practical engineering, because the exhaust hood was directly connected with the dust removal system, the size and flow of the exhaust hood were not easy to change once determined. When the actual exhaust air volume was much smaller than the exhaust air volume designed by the design method, it was difficult to obtain the optimal design parameters by using the traditional design method. Therefore, reasonable design of the size and flow of air supply outlet under the determined the form and flow of exhaust hood have strong practical significance. In this paper, numerical simulation was used to compare the flow field and the capture of pollutants under different forms of side suction exhaust hood and supply air device. On this basis, the air supply inlet were added, and the capture characteristics of different air supply flow rate on the pollutants were compared under the the constant exhaust flow. In addition, the effects of different air supply terminal devices on the capture of pollutants were studied. The results showed that movable exhaust hood and rotating open and closed exhaust hood could effectively improve the capture efficiency of pollutants. On this basis, the capture efficiency of pollutant could be improved by using air supply inlet, compared with using the exhaust hood alone. It was found that when the exhaust flow of the exhaust hood in the actual project was determined, the ratio of the exhaust flow should be adjusted on the premise that the supply air flow could effectively transport pollutants to the exhaust outlet. Finally, it was found that using parallel flow air supply device could improve the uniformity of air supply, improve the capture efficiency of exhaust hood. The results of the present study could provide certain guidance for the transformation and design of the push pull ventilation device in practical engineering.
2021, 39(10): 110-115,123.
doi: 10.13205/j.hjgc.202110015
Abstract:
Aiming at the problems of low temperature oxidation and self-heating of dried municipal sewage sludge, the exothermic characteristics of low temperature oxidation of the sludge with moisture content of 10%~70% (dry basis) at different temperatures (30℃~70℃) were studied with isothermal calorimetry. The results showed that the low temperature oxidation heat generation had three major mechanisms, including microbial biological oxidation, inorganic matters (Fe/S/O system) oxidation, organic matters chemical oxidation. The low temperature oxidation exothermic characteristics of the sludge were resulted from their comprehensive performance, and the overlapping of these three mechanisms jointly determined the self-heating characteristics of the sludge at low temperatures. The moisture content and ambient temperature affected the contribution of each heat source in process of sludge low-temperature oxidation, leading to the transformation of the main heat source and also having impact on the respective heat release characteristics of the three mechanisms. Increasing temperature and moisture content enhanced the heat generation of the sludge, then the self-heating potential became stronger, thus increased the risk of spontaneous combustion.
Aiming at the problems of low temperature oxidation and self-heating of dried municipal sewage sludge, the exothermic characteristics of low temperature oxidation of the sludge with moisture content of 10%~70% (dry basis) at different temperatures (30℃~70℃) were studied with isothermal calorimetry. The results showed that the low temperature oxidation heat generation had three major mechanisms, including microbial biological oxidation, inorganic matters (Fe/S/O system) oxidation, organic matters chemical oxidation. The low temperature oxidation exothermic characteristics of the sludge were resulted from their comprehensive performance, and the overlapping of these three mechanisms jointly determined the self-heating characteristics of the sludge at low temperatures. The moisture content and ambient temperature affected the contribution of each heat source in process of sludge low-temperature oxidation, leading to the transformation of the main heat source and also having impact on the respective heat release characteristics of the three mechanisms. Increasing temperature and moisture content enhanced the heat generation of the sludge, then the self-heating potential became stronger, thus increased the risk of spontaneous combustion.
2021, 39(10): 116-123.
doi: 10.13205/j.hjgc.202110016
Abstract:
Fly ash from domestic waste incineration contains organic matters such as dioxins, and heavy metals such as chromium and mercury. It is a highly hazardous solid waste, which has become one of the main sources of dioxin. This article focuses on the recent research status of different detoxification technologies of dioxin in fly ash, and systematically elaborates the technical principles, research status and development trend of different technologies. Cement kiln co-processing technology and low-temperature pyrolysis are the promising industrial applications technologies. Specifically, cement kiln co-processing technology can achieve high-efficiency degradation of dioxins without secondary pollutants. The limitation is that the technology needs to rely on the clinker production line, and the investment and operation cost of fly ash water washing pretreatment is relatively high. Low-temperature pyrolysis technology can be achieved efficiently in removal of dioxins in fly ash, while the dioxins may transfer from the solid phase to the gas phase. Usually, low-temperature pyrolysis technology is combined with other gas phase dioxin degradation technologies such as catalytic oxidation technology, which can achieve efficient gas phase dioxin degradation. This article aims to provide reference for the practical research of detoxification technology of dioxin in fly ash, and prospect the future degradation technology and development direction of dioxin in fly ash.
Fly ash from domestic waste incineration contains organic matters such as dioxins, and heavy metals such as chromium and mercury. It is a highly hazardous solid waste, which has become one of the main sources of dioxin. This article focuses on the recent research status of different detoxification technologies of dioxin in fly ash, and systematically elaborates the technical principles, research status and development trend of different technologies. Cement kiln co-processing technology and low-temperature pyrolysis are the promising industrial applications technologies. Specifically, cement kiln co-processing technology can achieve high-efficiency degradation of dioxins without secondary pollutants. The limitation is that the technology needs to rely on the clinker production line, and the investment and operation cost of fly ash water washing pretreatment is relatively high. Low-temperature pyrolysis technology can be achieved efficiently in removal of dioxins in fly ash, while the dioxins may transfer from the solid phase to the gas phase. Usually, low-temperature pyrolysis technology is combined with other gas phase dioxin degradation technologies such as catalytic oxidation technology, which can achieve efficient gas phase dioxin degradation. This article aims to provide reference for the practical research of detoxification technology of dioxin in fly ash, and prospect the future degradation technology and development direction of dioxin in fly ash.
2021, 39(10): 124-128.
doi: 10.13205/j.hjgc.202110017
Abstract:
In this paper, the physicochemical properties of fly ash from 14 municipal solid waste incinerators located in Northeast, North, East and South China were analysed, including their composition, loss on ignition and melting characteristics. The results showed that the content of CaO in fly ash of grate furnace was the highest in China, and the mass fraction of CaO was 40%~60%. The content of Cl was in the range of 20%~30%. At the same time, considerable contents of heavy metals which are easy to gasify were enriched in the fly ash. The loss on ignition of fly ash increased significantly with the increase of incineration temperature. When the temperature was 1200℃ above, it tended to be stable, and the highest loss on ignition was 40% above. The flow temperature of fly ash was most significantly affected by the content of SiO2, distributed in the range of 1100~1500℃.
In this paper, the physicochemical properties of fly ash from 14 municipal solid waste incinerators located in Northeast, North, East and South China were analysed, including their composition, loss on ignition and melting characteristics. The results showed that the content of CaO in fly ash of grate furnace was the highest in China, and the mass fraction of CaO was 40%~60%. The content of Cl was in the range of 20%~30%. At the same time, considerable contents of heavy metals which are easy to gasify were enriched in the fly ash. The loss on ignition of fly ash increased significantly with the increase of incineration temperature. When the temperature was 1200℃ above, it tended to be stable, and the highest loss on ignition was 40% above. The flow temperature of fly ash was most significantly affected by the content of SiO2, distributed in the range of 1100~1500℃.
2021, 39(10): 129-135.
doi: 10.13205/j.hjgc.202110018
Abstract:
Sludge-based biochar obtained from pyrolyzing sludge under anaerobic conditions can be used as soil amendment to improve contaminated soil. However, the possible pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals have potential environmental risks. The preparing of the environment-friendly biochar has become a prerequisite for subsequent utilization. In this research, four kinds of sludge-based biochar samples were respectively prepared at the different pyrolysis time (1~4 hours) under 500℃. It was found that the PAHs content in sludge-based biochar was significantly less than that in the raw sludge. The concentration of 4 kinds of PAHs (2~5 rings of PAHs) in the 4 kinds of sludge-based biochar increased firstly and then decreased with the pyrolysis duration increasing and reached the maximum in 2 hours, however the concentration of Σ16PAHs exceeded the agricultural limit. It showed that the duration of 2 hours was conducive to the full reaction of the organic matters in the original sludge to form new PAHs, and it also provided sufficient reaction time for the condensation of low-ring aromatic hydrocarbons to high-ring aromatic hydrocarbons. Since the most toxic BaP and DahA were not detected in the biochar during 2 hours, its corresponding toxic equivalents (TEQs) were also the lowest. Although the concentration in 1 hour did not exceed the agricultural standard in China, the TEQs was the highest, exceeding the threshold specified by the International Biochar Association. Considering the PAHs content and TEQs limit, the sludge based biochar prepared by pyrolysis time of 3 hours and 4 hours was much safer. From the perspective of energy conservation, 3 hours pyrolysis time were recommended.
Sludge-based biochar obtained from pyrolyzing sludge under anaerobic conditions can be used as soil amendment to improve contaminated soil. However, the possible pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals have potential environmental risks. The preparing of the environment-friendly biochar has become a prerequisite for subsequent utilization. In this research, four kinds of sludge-based biochar samples were respectively prepared at the different pyrolysis time (1~4 hours) under 500℃. It was found that the PAHs content in sludge-based biochar was significantly less than that in the raw sludge. The concentration of 4 kinds of PAHs (2~5 rings of PAHs) in the 4 kinds of sludge-based biochar increased firstly and then decreased with the pyrolysis duration increasing and reached the maximum in 2 hours, however the concentration of Σ16PAHs exceeded the agricultural limit. It showed that the duration of 2 hours was conducive to the full reaction of the organic matters in the original sludge to form new PAHs, and it also provided sufficient reaction time for the condensation of low-ring aromatic hydrocarbons to high-ring aromatic hydrocarbons. Since the most toxic BaP and DahA were not detected in the biochar during 2 hours, its corresponding toxic equivalents (TEQs) were also the lowest. Although the concentration in 1 hour did not exceed the agricultural standard in China, the TEQs was the highest, exceeding the threshold specified by the International Biochar Association. Considering the PAHs content and TEQs limit, the sludge based biochar prepared by pyrolysis time of 3 hours and 4 hours was much safer. From the perspective of energy conservation, 3 hours pyrolysis time were recommended.
2021, 39(10): 136-142.
doi: 10.13205/j.hjgc.202110019
Abstract:
Although lots of energy was consumed in municipal solid waste (MSW) classification transportation, little researches were focused on this process. The energy consumption analysis is not only the basis of the comprehensive evaluation of the environment and economic benefits of MSW classification, but also the basis for the designing of MSW classification and transportation systems. In this study, three typical scenarios (residential area, office/business area, and school area) of MSW classified transportation were developed and the energy consumption in each scenario was calculated. The results showed that:there was no significant difference in energy consumption in these three MSW classified transportation scenarios. Compared with the mixed MSW transportation, the energy consumption of classified transportation increased by 77%~116% (direct transportation) and 25%~42% (single stage transshipment), and the reduction of transportation energy consumption caused by transshipment was negatively related to the transportation distance. For each waste component, the energy consumption ascending order in transportation was food waste[0.09~0.10 kgce/(t·km) by direct transportation, 0.05~0.07 kgce/(t·km) by transshipment], residual waste or recyclables[0.11~0.13 kgce/(t·km) by direct transportation, 0.07~0.08 kgce/(t·km) by transshipment], and hazardous waste[0.21~0.30 kgce/(t·km) by direct transportation, 0.13~0.20 kgce/(t·km) by transshipment].
Although lots of energy was consumed in municipal solid waste (MSW) classification transportation, little researches were focused on this process. The energy consumption analysis is not only the basis of the comprehensive evaluation of the environment and economic benefits of MSW classification, but also the basis for the designing of MSW classification and transportation systems. In this study, three typical scenarios (residential area, office/business area, and school area) of MSW classified transportation were developed and the energy consumption in each scenario was calculated. The results showed that:there was no significant difference in energy consumption in these three MSW classified transportation scenarios. Compared with the mixed MSW transportation, the energy consumption of classified transportation increased by 77%~116% (direct transportation) and 25%~42% (single stage transshipment), and the reduction of transportation energy consumption caused by transshipment was negatively related to the transportation distance. For each waste component, the energy consumption ascending order in transportation was food waste[0.09~0.10 kgce/(t·km) by direct transportation, 0.05~0.07 kgce/(t·km) by transshipment], residual waste or recyclables[0.11~0.13 kgce/(t·km) by direct transportation, 0.07~0.08 kgce/(t·km) by transshipment], and hazardous waste[0.21~0.30 kgce/(t·km) by direct transportation, 0.13~0.20 kgce/(t·km) by transshipment].
2021, 39(10): 143-149.
doi: 10.13205/j.hjgc.202110020
Abstract:
As environmental protection policies has become stricter in oil and gas fields and the large output and low disposal rate of water-based drilling waste, how to effectively deal with solid waste from water-based drilling has become an urgent problem in the industry. In this paper, characteristics of water-based drilling waste were introduced. On this basis, advantages and disadvantages of treatment and disposal methods of drilling fluid and cuttings or dried mud were summarized and compared, including solidification or stabilization, solid-liquid separation, microbial treatment, incineration and landfill, etc. This paper puts forward four problems existing in disposal of water-based drilling waste in China, including attaching importance to oil-based waste rather than water-based waste, insufficient solid waste disposal capacity, lack of specifications and standards, and difficulty in treatment of some water-based drilling systems. On the basis of these problems, the future research focus is forecasted.
As environmental protection policies has become stricter in oil and gas fields and the large output and low disposal rate of water-based drilling waste, how to effectively deal with solid waste from water-based drilling has become an urgent problem in the industry. In this paper, characteristics of water-based drilling waste were introduced. On this basis, advantages and disadvantages of treatment and disposal methods of drilling fluid and cuttings or dried mud were summarized and compared, including solidification or stabilization, solid-liquid separation, microbial treatment, incineration and landfill, etc. This paper puts forward four problems existing in disposal of water-based drilling waste in China, including attaching importance to oil-based waste rather than water-based waste, insufficient solid waste disposal capacity, lack of specifications and standards, and difficulty in treatment of some water-based drilling systems. On the basis of these problems, the future research focus is forecasted.
2021, 39(10): 150-156.
doi: 10.13205/j.hjgc.202110021
Abstract:
In this paper, bauxite tailings were used as the raw material, and the acid leaching impurity removal process was adopted, concentrates with different Fe2O3 and K2O contents were obtained by controlling the concentration of hydrochloric acid and the liquid-solid ratio in the process of hydrochloric acid leaching. The influence mechanism of different binary impurity composition on the microscopic morphology, phase composition, normal temperature mechanical properties and high temperature performance of the samples was studied, and the optimal hydrochloric acid concentration and the leaching liquid-solid ratio were obtained. The results showed that when the content of Fe2O3 and K2O in the tailings were both less than 2.0%, the crystalline phase content and load softening temperature of the material were higher; when the content of impurity Fe2O3 was greater than 2.0% and greatly increased, the amorphous phase content of the material increased rapidly, performance under high temperature decreased, but performance under room temperature increased. When controlling the content of Fe2O3 and K2O in the bauxite tailings of less than 2%, the load softening temperature was maintained above 1400℃, which met the requirements of the standard for commercially available NZ-45 refractory bricks.
In this paper, bauxite tailings were used as the raw material, and the acid leaching impurity removal process was adopted, concentrates with different Fe2O3 and K2O contents were obtained by controlling the concentration of hydrochloric acid and the liquid-solid ratio in the process of hydrochloric acid leaching. The influence mechanism of different binary impurity composition on the microscopic morphology, phase composition, normal temperature mechanical properties and high temperature performance of the samples was studied, and the optimal hydrochloric acid concentration and the leaching liquid-solid ratio were obtained. The results showed that when the content of Fe2O3 and K2O in the tailings were both less than 2.0%, the crystalline phase content and load softening temperature of the material were higher; when the content of impurity Fe2O3 was greater than 2.0% and greatly increased, the amorphous phase content of the material increased rapidly, performance under high temperature decreased, but performance under room temperature increased. When controlling the content of Fe2O3 and K2O in the bauxite tailings of less than 2%, the load softening temperature was maintained above 1400℃, which met the requirements of the standard for commercially available NZ-45 refractory bricks.
2021, 39(10): 157-162,149.
doi: 10.13205/j.hjgc.202110022
Abstract:
In order to clarify the distribution characteristics of water-soluble ions in the soils, dust and coke quenching slag around the coke oven, the samples around the coke oven were collected. Ions (SO42-, NO3-, Cl-, F-, NH4+, Na+, Ca2+, K+, and Mg2+) in the samples were analyzed using ICS-90 ion chromatograph (Dionex, USA).The results showed that the mass fractions of water-soluble ions in the soils, dust and coke quenching slag around the coke oven were 1.65, 5.27, 2.19 g/kg, respectively. The variation coefficients of SO42- and NH4+ in the soils around the coke oven were 84.22% and 51.17%, suggesting that the soils were affected differently by pollutants emitted during coking process. The soil inside the coking plant were more susceptible to pollutants emitted from coking process, than those in the soil outside the coking plant. The NO3-/SO42- ratios in the dust near combustion chamber exhaust chimney and in south of quenching tower were 0.46 and 0.03, respectively, indicating that the dust around the coke oven was also affected by the pollutants emitted from coking process. The mass fractions of total water-soluble ions and SO42- in the dust in south of quenching tower were 6.99 times and 18.44 times those of the dust next to combustion chamber exhaust chimney, respectively. The distribution characteristic of water-soluble ions in coke quenching slag was almost the same as that in dust in south of quenching tower, and there was a significant correlation between coke quenching slag and dust in south of quenching tower. SO42- was a water-soluble ion with the highest mass fraction in the soils, dust and coke quenching slag around the coke oven. Therefore, it was suggested to strengthen the control of particulate matter and SO2 emission in the coking process.
In order to clarify the distribution characteristics of water-soluble ions in the soils, dust and coke quenching slag around the coke oven, the samples around the coke oven were collected. Ions (SO42-, NO3-, Cl-, F-, NH4+, Na+, Ca2+, K+, and Mg2+) in the samples were analyzed using ICS-90 ion chromatograph (Dionex, USA).The results showed that the mass fractions of water-soluble ions in the soils, dust and coke quenching slag around the coke oven were 1.65, 5.27, 2.19 g/kg, respectively. The variation coefficients of SO42- and NH4+ in the soils around the coke oven were 84.22% and 51.17%, suggesting that the soils were affected differently by pollutants emitted during coking process. The soil inside the coking plant were more susceptible to pollutants emitted from coking process, than those in the soil outside the coking plant. The NO3-/SO42- ratios in the dust near combustion chamber exhaust chimney and in south of quenching tower were 0.46 and 0.03, respectively, indicating that the dust around the coke oven was also affected by the pollutants emitted from coking process. The mass fractions of total water-soluble ions and SO42- in the dust in south of quenching tower were 6.99 times and 18.44 times those of the dust next to combustion chamber exhaust chimney, respectively. The distribution characteristic of water-soluble ions in coke quenching slag was almost the same as that in dust in south of quenching tower, and there was a significant correlation between coke quenching slag and dust in south of quenching tower. SO42- was a water-soluble ion with the highest mass fraction in the soils, dust and coke quenching slag around the coke oven. Therefore, it was suggested to strengthen the control of particulate matter and SO2 emission in the coking process.
2021, 39(10): 163-170.
doi: 10.13205/j.hjgc.202110023
Abstract:
FeSN-Ccomposite catalytic material was prepared by hydration-pyrolyzation-carbonization using baycherry as a biomass and Fe2(SO4)3 as the doping source. FeSN-C composite catalytic material was characterized and applied as a cathode of microbial fuel cells (MFC) to drive the oxygen reduction reaction(ORR). The results showed that FeSN-C cathode performed well in electricity generation, producing the peak output voltage and power density of 550 mV and 854 mW/m2, which were 98.6% and 83.2% of that of commercial platinum carbon (Pt/C),respectively. At the same time, FeSN-C cathode had a small overpotential and high electron transfer number for ORR (n=3.78), dominated by the four electronic transfer reaction process. Further compared to the commercial platinum carbon product, FeSN-C had stronger stability, which was reduced by 17.1% in the current attenuation test, lower than 23.5% of the Pt/C cathode. The doping of Fe, S and N atoms led to a large collapse of the carbon skeleton, where more active sites were exposed. Meanwhile, the synergy between Fe, S, N was the key to improve the ORR of the cathode.
FeSN-Ccomposite catalytic material was prepared by hydration-pyrolyzation-carbonization using baycherry as a biomass and Fe2(SO4)3 as the doping source. FeSN-C composite catalytic material was characterized and applied as a cathode of microbial fuel cells (MFC) to drive the oxygen reduction reaction(ORR). The results showed that FeSN-C cathode performed well in electricity generation, producing the peak output voltage and power density of 550 mV and 854 mW/m2, which were 98.6% and 83.2% of that of commercial platinum carbon (Pt/C),respectively. At the same time, FeSN-C cathode had a small overpotential and high electron transfer number for ORR (n=3.78), dominated by the four electronic transfer reaction process. Further compared to the commercial platinum carbon product, FeSN-C had stronger stability, which was reduced by 17.1% in the current attenuation test, lower than 23.5% of the Pt/C cathode. The doping of Fe, S and N atoms led to a large collapse of the carbon skeleton, where more active sites were exposed. Meanwhile, the synergy between Fe, S, N was the key to improve the ORR of the cathode.
2021, 39(10): 178-184.
doi: 10.13205/j.hjgc.202110025
Abstract:
Two oxidants, H2O2 and Na2FeO4, were used to remove TPH from soil. The reaction kinetic model was established according to the relationship between reaction conditions and reaction rate. The factors such as reaction rate change, half-life and TPH removal rate in the reaction process were discussed and compared, and their reaction laws were also found out. The results showed that the process of removing TPH by H2O2 conformed to the first-order reaction kinetic model. The process of removing TPH by Na2FeO4 conformed to the second-order reaction kinetic model. The increase of H2O2 concentration led to the increase of reaction kinetic constant, and the increase of Na2FeO4 concentration led to the decrease of reaction kinetic constant. The initial reaction rates of H2O2 solution with TPH at concentrations of 0.078, 0.156, 0.234 mol/L TPH were 0.61×10-3, 1.38×10-3, 2.09×10-3 mol/(L·min). The initial reaction rates of Na2FeO4 solution with TPH at three concentrations of 0.070, 0.140 and 0.210 mol/L were 13.30×10-3, 20.47×10-3, 12.86×10-3 mol/(L·min). The reaction rates of the two oxidants with TPH were in the order of Na2FeO4>H2O2. The half-life of H2O2 reacted with TPH was 40.40~66.50 min, and the half-life of Na2FeO4 reacted with TPH was 4.10~7.14 min. The half-life of H2O2 was about 10 times of that of Na2FeO4. The removal rate of TPH in the soil by the two oxidants could reach more than 60%, which would not cause residue in the soil, but the utilization rate was low. The characteristics of the reaction rate, half-life and removal rate of the two oxidants in the process of removing TPH were summarized. Finally, the paper screened and optimized the reaction conditions to provide a theoretical basis for soil remediation in the Loess Plateau.
Two oxidants, H2O2 and Na2FeO4, were used to remove TPH from soil. The reaction kinetic model was established according to the relationship between reaction conditions and reaction rate. The factors such as reaction rate change, half-life and TPH removal rate in the reaction process were discussed and compared, and their reaction laws were also found out. The results showed that the process of removing TPH by H2O2 conformed to the first-order reaction kinetic model. The process of removing TPH by Na2FeO4 conformed to the second-order reaction kinetic model. The increase of H2O2 concentration led to the increase of reaction kinetic constant, and the increase of Na2FeO4 concentration led to the decrease of reaction kinetic constant. The initial reaction rates of H2O2 solution with TPH at concentrations of 0.078, 0.156, 0.234 mol/L TPH were 0.61×10-3, 1.38×10-3, 2.09×10-3 mol/(L·min). The initial reaction rates of Na2FeO4 solution with TPH at three concentrations of 0.070, 0.140 and 0.210 mol/L were 13.30×10-3, 20.47×10-3, 12.86×10-3 mol/(L·min). The reaction rates of the two oxidants with TPH were in the order of Na2FeO4>H2O2. The half-life of H2O2 reacted with TPH was 40.40~66.50 min, and the half-life of Na2FeO4 reacted with TPH was 4.10~7.14 min. The half-life of H2O2 was about 10 times of that of Na2FeO4. The removal rate of TPH in the soil by the two oxidants could reach more than 60%, which would not cause residue in the soil, but the utilization rate was low. The characteristics of the reaction rate, half-life and removal rate of the two oxidants in the process of removing TPH were summarized. Finally, the paper screened and optimized the reaction conditions to provide a theoretical basis for soil remediation in the Loess Plateau.
2021, 39(10): 185-190.
doi: 10.13205/j.hjgc.202110026
Abstract:
To control water-soluble Cr(Ⅵ) compound in cement clinker from the waste source into the kiln, and make sure the reasonable co-processing of chromium contaminated soil, this paper put forward the conversion rate from Cr(Ⅲ) in raw materials to Cr(Ⅵ) and water soluble Cr(Ⅵ) in the clinker as the breakthrough point and then conduct a research. The experiments were carried out under simulated and field test conditions, and the results were calculated through mass balancing method and conversion rate of Cr(Ⅵ). It was found that the total amount of Cr changed slightly before and after calcination, and the conversion rates of Cr(Ⅲ) to Cr(Ⅵ) in simulated calcination experiment and field test were 40% and 90%, respectively. The water-soluble Cr(Ⅵ) was only detected in clinker in filed test, with a proportion of 60%~69% of total Cr(Ⅵ). Eventually, the conversion rate of water-soluble Cr (Ⅵ) was calculated to be approximately 35.40%. The mixing degree of air and raw material showed an significant impact on the conversion rate of Cr(Ⅲ) to water-soluble Cr(Ⅵ). The analysis of cement product revealed that the concentration of water-soluble Cr(Ⅵ) was slightly higher in composite Portland cement, but still below the allowable limit in China's nation standard GB 31893-2015.
To control water-soluble Cr(Ⅵ) compound in cement clinker from the waste source into the kiln, and make sure the reasonable co-processing of chromium contaminated soil, this paper put forward the conversion rate from Cr(Ⅲ) in raw materials to Cr(Ⅵ) and water soluble Cr(Ⅵ) in the clinker as the breakthrough point and then conduct a research. The experiments were carried out under simulated and field test conditions, and the results were calculated through mass balancing method and conversion rate of Cr(Ⅵ). It was found that the total amount of Cr changed slightly before and after calcination, and the conversion rates of Cr(Ⅲ) to Cr(Ⅵ) in simulated calcination experiment and field test were 40% and 90%, respectively. The water-soluble Cr(Ⅵ) was only detected in clinker in filed test, with a proportion of 60%~69% of total Cr(Ⅵ). Eventually, the conversion rate of water-soluble Cr (Ⅵ) was calculated to be approximately 35.40%. The mixing degree of air and raw material showed an significant impact on the conversion rate of Cr(Ⅲ) to water-soluble Cr(Ⅵ). The analysis of cement product revealed that the concentration of water-soluble Cr(Ⅵ) was slightly higher in composite Portland cement, but still below the allowable limit in China's nation standard GB 31893-2015.
2021, 39(10): 191-196,156.
doi: 10.13205/j.hjgc.202110027
Abstract:
Soil is the source and sink of volatile organic compounds. It is of great significance to study the adsorption behavior of pollutants in soil for environmental fate and ecological risk. Based on the comprehensive analysis of the basic physical and chemical properties of 12 kinds of zonal soils in China, the distribution law of aniline at the soil water interface and the relationship between the adsorption behaviors and the physical and chemical properties of soil were discussed. The results showed that:1) the adsorption capacity of Heilongjiang black soil for aniline was the strongest, and the theoretical saturated adsorption capacity was the largest; 2) considering that the adsorption isotherms of some soil samples showed obvious nonlinearity, Freundlich model was used to fit the isotherms of aniline adsorbed by soil; 3) the physical and chemical properties of 12 zonal soils were significantly different; 4) the content of organic matter has the most significant effect on the adsorption behavior of aniline at the soil water interface:the higher the content of organic matter, the stronger the adsorption capacity of soil for aniline.
Soil is the source and sink of volatile organic compounds. It is of great significance to study the adsorption behavior of pollutants in soil for environmental fate and ecological risk. Based on the comprehensive analysis of the basic physical and chemical properties of 12 kinds of zonal soils in China, the distribution law of aniline at the soil water interface and the relationship between the adsorption behaviors and the physical and chemical properties of soil were discussed. The results showed that:1) the adsorption capacity of Heilongjiang black soil for aniline was the strongest, and the theoretical saturated adsorption capacity was the largest; 2) considering that the adsorption isotherms of some soil samples showed obvious nonlinearity, Freundlich model was used to fit the isotherms of aniline adsorbed by soil; 3) the physical and chemical properties of 12 zonal soils were significantly different; 4) the content of organic matter has the most significant effect on the adsorption behavior of aniline at the soil water interface:the higher the content of organic matter, the stronger the adsorption capacity of soil for aniline.
2021, 39(10): 197-200,212.
doi: 10.13205/j.hjgc.202110028
Abstract:
Environmental assessment management, pollutant discharge permit and environmental law enforcement are the three important management systems for constructing the environmental management system of fixed pollution sources. This paper combed the main environmental problems existing in tailings ponds in China, and analyzed the current situation of environmental impact assessment management, pollutant discharge permit and environmental protection law enforcement management of tailings ponds. In general, the environmental impact assessment management of tailings pond achieved scientific rating and supervision. The information about tailings pond in the pollutant discharge permit of most enterprises was incomplete or missing. The pollution control effect of some tailing ponds needed to be improved. In view of the problems existing in the connection of tailings pond system, this paper put forward opinions and suggestions, and pointed out that opening up the three systems of tailings pond environmental impact assessment management, pollutant discharge permit and environmental protection law enforcement management, and promoting the connection of environmental impact assessment, pollutant discharge permit and law enforcement were important measures to comprehensively improve the environmental management level of tailings pond. The results could provide references for promoting the whole process environmental management of tailings pond.
Environmental assessment management, pollutant discharge permit and environmental law enforcement are the three important management systems for constructing the environmental management system of fixed pollution sources. This paper combed the main environmental problems existing in tailings ponds in China, and analyzed the current situation of environmental impact assessment management, pollutant discharge permit and environmental protection law enforcement management of tailings ponds. In general, the environmental impact assessment management of tailings pond achieved scientific rating and supervision. The information about tailings pond in the pollutant discharge permit of most enterprises was incomplete or missing. The pollution control effect of some tailing ponds needed to be improved. In view of the problems existing in the connection of tailings pond system, this paper put forward opinions and suggestions, and pointed out that opening up the three systems of tailings pond environmental impact assessment management, pollutant discharge permit and environmental protection law enforcement management, and promoting the connection of environmental impact assessment, pollutant discharge permit and law enforcement were important measures to comprehensively improve the environmental management level of tailings pond. The results could provide references for promoting the whole process environmental management of tailings pond.
2021, 39(10): 201-206,170.
doi: 10.13205/j.hjgc.202110029
Abstract:
In this paper, the current situation of solid waste recycling in China was arranged, the current solid waste treatment mechanism, management ideas and methods, collaborative disposal and other issues were analyzed. Based on the whole life cycle theory, green cycle and low-carbon development ideas and methods, this paper carried out the whole life cycle optimization management of solid waste classification and resource utilization, and proposed that green ecological design and clean production should be carried out in the industrial production and manufacturing links; green supply chain and green consumption lifestyle should be constructed in the circulation consumption links. This paper points out that in the process of recovery and disposal, it is necessary to explore new business models and increase the technological innovation of solid waste recycling in key fields.
In this paper, the current situation of solid waste recycling in China was arranged, the current solid waste treatment mechanism, management ideas and methods, collaborative disposal and other issues were analyzed. Based on the whole life cycle theory, green cycle and low-carbon development ideas and methods, this paper carried out the whole life cycle optimization management of solid waste classification and resource utilization, and proposed that green ecological design and clean production should be carried out in the industrial production and manufacturing links; green supply chain and green consumption lifestyle should be constructed in the circulation consumption links. This paper points out that in the process of recovery and disposal, it is necessary to explore new business models and increase the technological innovation of solid waste recycling in key fields.
2021, 39(10): 207-212.
doi: 10.13205/j.hjgc.202110030
Abstract:
A health assessment method for the Yangtze River estuary ecosystem, which was considered as the terminal receptor of the Yangtze River basin, was established based on the conceptual framework of PSR (press-state-response). The main contents included:an ecosystem health assessment indicators system in which pressure, state and response parameters was taken into consideration; the weight of the indicators was determined by the analytic hierarchy process (AHP) method; the health of the Yangtze River estuary ecosystem was divided into five grades, "excellent" "good" "medium" "bad" and "poor". The health status of the Yangtze River estuary ecosystem from 2001 to 2017 was evaluated by this method. The results of ecosystem health of the Yangtze River estuary during 2001-2017 showed that the pressure index values were between 0.08 and 0.47 and showed a trend of fluctuating downward, the state index showed a trend of falling after rising first with the values fluctuated between 0.40 and 0.88, the response index values fluctuated between 0.45 and 0.94 and showed a trend of fluctuating upward. The EEHI value was between 0.40 and 0.65 during the 17 years, 2001 to 2017. The EEHI dropped from 2001 to 2006, then rise slowly. According to the EEHI value, although the grade of the health of Yangtze River estuary ecosystem in 2012, 2013 and 2015 achieve "good" level, and the health of the Yangtze River estuary ecosystem was graded as "medium" level in most of the years. The main factors affecting the health assessment index of the Yangtze River estuary were the decrease of sediment inflow, the high shock of nitrogen and phosphorus concentration in the Yangtze River estuary, the instability of plankton structure and the frequent occurrence of red tides.
A health assessment method for the Yangtze River estuary ecosystem, which was considered as the terminal receptor of the Yangtze River basin, was established based on the conceptual framework of PSR (press-state-response). The main contents included:an ecosystem health assessment indicators system in which pressure, state and response parameters was taken into consideration; the weight of the indicators was determined by the analytic hierarchy process (AHP) method; the health of the Yangtze River estuary ecosystem was divided into five grades, "excellent" "good" "medium" "bad" and "poor". The health status of the Yangtze River estuary ecosystem from 2001 to 2017 was evaluated by this method. The results of ecosystem health of the Yangtze River estuary during 2001-2017 showed that the pressure index values were between 0.08 and 0.47 and showed a trend of fluctuating downward, the state index showed a trend of falling after rising first with the values fluctuated between 0.40 and 0.88, the response index values fluctuated between 0.45 and 0.94 and showed a trend of fluctuating upward. The EEHI value was between 0.40 and 0.65 during the 17 years, 2001 to 2017. The EEHI dropped from 2001 to 2006, then rise slowly. According to the EEHI value, although the grade of the health of Yangtze River estuary ecosystem in 2012, 2013 and 2015 achieve "good" level, and the health of the Yangtze River estuary ecosystem was graded as "medium" level in most of the years. The main factors affecting the health assessment index of the Yangtze River estuary were the decrease of sediment inflow, the high shock of nitrogen and phosphorus concentration in the Yangtze River estuary, the instability of plankton structure and the frequent occurrence of red tides.
