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2022 Vol. 40, No. 9
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2022, 40(9): 1-8.
doi: 10.13205/j.hjgc.202209001
Abstract:
To promote the implementation of China's Dual Carbon Goals policy and expand the recycling technology of CO2, the experimental exploration of CO2 synthesis of diesel was carried out in this paper. Using iron-based catalyst and CO2 as the raw material, the feasibility study of CO2 hydrogenation synthesis of diesel was discussed. Based on verifying the feasibility of CO2 synthesis to derive diesel, we further investigated the effect of catalyst carrier's acidity and alkalinity, catalyst component Fe content and additive addition on catalytic activity. The research showed that the main components and component distribution characteristics of the synthesis products of CO2 hydrogenation were highly consistent with those of commercial diesel. The iron-based catalyst supported by γ-Al2O3 could effectively promote the reverse water gas reaction of CO2 and the Fenton reaction. As a catalyst promoter, the addition of potassium had a good auxiliary effect on improving the catalytic activity. The reaction temperature and pressure were the controllable factors of the reaction, and the pressure was the decisive factor. The study found that only when the pressure was higher than 1.6 MPa, the reaction smoothly occured in the temperature range above 250 ℃. In addition, the acidity and alkalinity of the carrier, the content of the catalytic component Fe and the auxiliary K had a crucial influence on the composition characteristics of the synthesized products and similarity with diesel.
To promote the implementation of China's Dual Carbon Goals policy and expand the recycling technology of CO2, the experimental exploration of CO2 synthesis of diesel was carried out in this paper. Using iron-based catalyst and CO2 as the raw material, the feasibility study of CO2 hydrogenation synthesis of diesel was discussed. Based on verifying the feasibility of CO2 synthesis to derive diesel, we further investigated the effect of catalyst carrier's acidity and alkalinity, catalyst component Fe content and additive addition on catalytic activity. The research showed that the main components and component distribution characteristics of the synthesis products of CO2 hydrogenation were highly consistent with those of commercial diesel. The iron-based catalyst supported by γ-Al2O3 could effectively promote the reverse water gas reaction of CO2 and the Fenton reaction. As a catalyst promoter, the addition of potassium had a good auxiliary effect on improving the catalytic activity. The reaction temperature and pressure were the controllable factors of the reaction, and the pressure was the decisive factor. The study found that only when the pressure was higher than 1.6 MPa, the reaction smoothly occured in the temperature range above 250 ℃. In addition, the acidity and alkalinity of the carrier, the content of the catalytic component Fe and the auxiliary K had a crucial influence on the composition characteristics of the synthesized products and similarity with diesel.
2022, 40(9): 9-18.
doi: 10.13205/j.hjgc.202209002
Abstract:
The current impact of air pollutants on the regional economy and human health cannot be ignored. This paper selected data on atmospheric pollutants and meteorological elements in Xuzhou from January 1, 2016 to January 24, 2021. Given the characteristics of strong fluctuation of atmospheric pollutant concentration, the pollutant data were decomposed into intrinsic mode fuction by using complementary ensemble empirical mode decomposition(CEEMD), and various features of the original data were extracted. Each decomposed intrinsic mode fuction was used as the input layer of the bidirectional gated recurrent model(BiGRU). Through bidirectional cyclic training, the characteristic trend of each component was learned and the optimal training parameters were obtained. The output results of each intrinsic mode fuction were reconstructed to obtain the final predicted value. The results showed that compared with the BiGRU and BP models, MAE, RMSE and MAPE of each air pollutant predicted by CEEMD-BiGRU model were reduced by more than 15%, 20% and 2 percentage points, and the prediction accuracy was greatly improved. On this basis, CEEMD-BiGRU model was used to predict the residuals of the latter period to correct the original prediction values and obtain the upper bound of the prediction interval for air pollutants, further to extend the applicability of the model.
The current impact of air pollutants on the regional economy and human health cannot be ignored. This paper selected data on atmospheric pollutants and meteorological elements in Xuzhou from January 1, 2016 to January 24, 2021. Given the characteristics of strong fluctuation of atmospheric pollutant concentration, the pollutant data were decomposed into intrinsic mode fuction by using complementary ensemble empirical mode decomposition(CEEMD), and various features of the original data were extracted. Each decomposed intrinsic mode fuction was used as the input layer of the bidirectional gated recurrent model(BiGRU). Through bidirectional cyclic training, the characteristic trend of each component was learned and the optimal training parameters were obtained. The output results of each intrinsic mode fuction were reconstructed to obtain the final predicted value. The results showed that compared with the BiGRU and BP models, MAE, RMSE and MAPE of each air pollutant predicted by CEEMD-BiGRU model were reduced by more than 15%, 20% and 2 percentage points, and the prediction accuracy was greatly improved. On this basis, CEEMD-BiGRU model was used to predict the residuals of the latter period to correct the original prediction values and obtain the upper bound of the prediction interval for air pollutants, further to extend the applicability of the model.
2022, 40(9): 19-25,43.
doi: 10.13205/j.hjgc.202209003
Abstract:
Due to the special process of the coking plant, the emission problems of sulfur dioxide, nitrogen oxides, particulate matter and VOCs are more prominent. Therefore, the emission characteristics of VOCs in the ambient air at the boundary of the coking plant were analyzed, the ozone formation potential of VOCs was evaluated according to the maximum incremental reaction activity method(MIR) and propylene-equivalent concentration method(PEC), and the secondary organic aerosol formation potential of VOCs was evaluated, according to the fractional aerosol coefficients method(FAC). The results showed that: 1) a total of 17 VOCs including aromatic hydrocarbons, halogenated hydrocarbons, olefins, sulfides and ketones were analyzed at five points in the upwind and downwind direction of the factory boundary. 2) There were significant differences in VOCs detected at the plant boundary in different regions, and the total mass concentration was 28.2~167.9 μg/m3, in which aromatic hydrocarbons accounted for the largest proportion in TVOCs at each point, reaching 51.01%~84.63%. 3) The OFP at the boundary of the cold drum of desulfurization and salt extraction was the largest, with a theoretical value of 335.51 μg/m3, and the OFP at the boundary of office and living area was the smallest, with a theoretical value of 47.06 μg/m3. The contribution rate of aromatic hydrocarbons to OFP was 27.21%~62.37%, that of olefins was 39.17%~61.84%, and that of halogenated hydrocarbons was 2.08%~14.56%. The change trend of OFP estimated by PEC method was consistent with that of MIR method, and the propylene-equivalent concentration range was 3.11~31.89 μg/m3; the contribution rates of propylene-equivalent concentration of aromatic hydrocarbons at each point were 37.10%, 51.46%, 66.79%, 58.80% and 22.74%, respectively. 4) The formation potential of SOA at each point was 0.452, 0.938, 2.517, 4.055, 0.495 μg/m3, respectively; aromatic hydrocarbons contributed the most to the formation potential of SOA. Substances with high mass concentration and reaction activity, such as propylene, toluene, xylene and vinyl chloride, were the VOCs components that need priority control and could be used as markers of VOCs in the ambient air of coking plants.
Due to the special process of the coking plant, the emission problems of sulfur dioxide, nitrogen oxides, particulate matter and VOCs are more prominent. Therefore, the emission characteristics of VOCs in the ambient air at the boundary of the coking plant were analyzed, the ozone formation potential of VOCs was evaluated according to the maximum incremental reaction activity method(MIR) and propylene-equivalent concentration method(PEC), and the secondary organic aerosol formation potential of VOCs was evaluated, according to the fractional aerosol coefficients method(FAC). The results showed that: 1) a total of 17 VOCs including aromatic hydrocarbons, halogenated hydrocarbons, olefins, sulfides and ketones were analyzed at five points in the upwind and downwind direction of the factory boundary. 2) There were significant differences in VOCs detected at the plant boundary in different regions, and the total mass concentration was 28.2~167.9 μg/m3, in which aromatic hydrocarbons accounted for the largest proportion in TVOCs at each point, reaching 51.01%~84.63%. 3) The OFP at the boundary of the cold drum of desulfurization and salt extraction was the largest, with a theoretical value of 335.51 μg/m3, and the OFP at the boundary of office and living area was the smallest, with a theoretical value of 47.06 μg/m3. The contribution rate of aromatic hydrocarbons to OFP was 27.21%~62.37%, that of olefins was 39.17%~61.84%, and that of halogenated hydrocarbons was 2.08%~14.56%. The change trend of OFP estimated by PEC method was consistent with that of MIR method, and the propylene-equivalent concentration range was 3.11~31.89 μg/m3; the contribution rates of propylene-equivalent concentration of aromatic hydrocarbons at each point were 37.10%, 51.46%, 66.79%, 58.80% and 22.74%, respectively. 4) The formation potential of SOA at each point was 0.452, 0.938, 2.517, 4.055, 0.495 μg/m3, respectively; aromatic hydrocarbons contributed the most to the formation potential of SOA. Substances with high mass concentration and reaction activity, such as propylene, toluene, xylene and vinyl chloride, were the VOCs components that need priority control and could be used as markers of VOCs in the ambient air of coking plants.
2022, 40(9): 26-32.
doi: 10.13205/j.hjgc.202209004
Abstract:
To investigate the seasonal characteristics and sources of water-soluble ions in PM1 in the southwest suburb of Chengdu, samples were collected during typical seasonal months(January, April, July and October)of 2019, and 8 main kinds of water-soluble ions, including NO3-, SO42-, NH4+, Ca2+, Cl-, K+, Na+, Mg2+ in the samples were detected, and finally the mass concentrations and correlation among PM1 and its water-soluble ions components were analyzed in this research. The result showed that the annual average concentrations of PM1 and total water-soluble ions were(30.1±12.5) μg/m3 and(8.5±6.2) μg/m3, respectively. Concentrations of ions were, from more to less, in an order of NO3->SO42->NH4+>K+>Ca2+>Cl->Na+>Mg2+. Secondary ions(SNA) contributed as high as 90.0% of the total water-soluble ions, and their contributions to PM1 were different between seasons, which were 35.0%, 23.6%, 22.0% and 17.5% in winter, spring, autumn and summer, respectively. The ratios of NO3-/SO42- were 0.9 and 0.6 in spring and summer, and 1.2 and 2.1 in autumn and winter, which revealed that the vehicle sources played an important role in the formation of PM1 in autumn and winter. The mean values of sulfur oxidation rate(SOR) and nitrogen oxidation rate(NOR) were 0.37 and 0.04, due to the variations in sources and meteorological conditions, respectively, indicating that there was a higher secondary aerosol transformation rate of sulfur. The results of principle component analysis indicated that the secondary inorganic sources, coal combustion, biomass burning and dust were the main sources of the water-soluble ions during the sampling periods.
To investigate the seasonal characteristics and sources of water-soluble ions in PM1 in the southwest suburb of Chengdu, samples were collected during typical seasonal months(January, April, July and October)of 2019, and 8 main kinds of water-soluble ions, including NO3-, SO42-, NH4+, Ca2+, Cl-, K+, Na+, Mg2+ in the samples were detected, and finally the mass concentrations and correlation among PM1 and its water-soluble ions components were analyzed in this research. The result showed that the annual average concentrations of PM1 and total water-soluble ions were(30.1±12.5) μg/m3 and(8.5±6.2) μg/m3, respectively. Concentrations of ions were, from more to less, in an order of NO3->SO42->NH4+>K+>Ca2+>Cl->Na+>Mg2+. Secondary ions(SNA) contributed as high as 90.0% of the total water-soluble ions, and their contributions to PM1 were different between seasons, which were 35.0%, 23.6%, 22.0% and 17.5% in winter, spring, autumn and summer, respectively. The ratios of NO3-/SO42- were 0.9 and 0.6 in spring and summer, and 1.2 and 2.1 in autumn and winter, which revealed that the vehicle sources played an important role in the formation of PM1 in autumn and winter. The mean values of sulfur oxidation rate(SOR) and nitrogen oxidation rate(NOR) were 0.37 and 0.04, due to the variations in sources and meteorological conditions, respectively, indicating that there was a higher secondary aerosol transformation rate of sulfur. The results of principle component analysis indicated that the secondary inorganic sources, coal combustion, biomass burning and dust were the main sources of the water-soluble ions during the sampling periods.
2022, 40(9): 33-43.
doi: 10.13205/j.hjgc.202209005
Abstract:
Using meteorological and environmental monitoring data, the pollution events, concentration variation characteristics and pollutant correlation of PM2.5 in Shenyang from 2015 to 2018 were analyzed. Using WRF-Chem and HYSPLIT model, a pollution process in Shenyang in 2018 was analyzed from the aspects of meteorological elements, high-altitude circulation situation and pollution transmission characteristics. The results indicated that the monthly concentration showed the characteristics of V-shaped, with a sequence of winter>spring>autumn>summer, and the daily concentration showed the characteristics of double peak. Correlation analysis showed that temperature(-0.3666) and relative humidity(-0.1158) were the main meteorological factors affecting PM2.5 concentration, while PM10(0.9964) and NO2(0.7242) were the main pollutants. From January 26th to 28th in 2018, a heavy pollution process occurred in Shenyang. At the beginning of the pollution, the high-altitude circulation was flat, the warm advection in front of the shallow trough was dominant, the ground was controlled by a weak high-pressure pressure equalizing field, the ground wind speed was dominated by the static and light wind, and the wind field convergence was conducive to the accumulation of pollutants. In the development process of pollution, the increase of ground relative humidity was conducive to the growth of particle moisture absorption; the thickness of ground and high-altitude inversion layer were large, and then the pollution was intensified. In the weakening process of pollution, the inversion layer disappeared, the stratification was stable, and the vertical diffusion conditions turned better. The accumulation of local pollutants and external transmission under static and stable meteorological conditions were the main reason of the heavy pollution.
Using meteorological and environmental monitoring data, the pollution events, concentration variation characteristics and pollutant correlation of PM2.5 in Shenyang from 2015 to 2018 were analyzed. Using WRF-Chem and HYSPLIT model, a pollution process in Shenyang in 2018 was analyzed from the aspects of meteorological elements, high-altitude circulation situation and pollution transmission characteristics. The results indicated that the monthly concentration showed the characteristics of V-shaped, with a sequence of winter>spring>autumn>summer, and the daily concentration showed the characteristics of double peak. Correlation analysis showed that temperature(-0.3666) and relative humidity(-0.1158) were the main meteorological factors affecting PM2.5 concentration, while PM10(0.9964) and NO2(0.7242) were the main pollutants. From January 26th to 28th in 2018, a heavy pollution process occurred in Shenyang. At the beginning of the pollution, the high-altitude circulation was flat, the warm advection in front of the shallow trough was dominant, the ground was controlled by a weak high-pressure pressure equalizing field, the ground wind speed was dominated by the static and light wind, and the wind field convergence was conducive to the accumulation of pollutants. In the development process of pollution, the increase of ground relative humidity was conducive to the growth of particle moisture absorption; the thickness of ground and high-altitude inversion layer were large, and then the pollution was intensified. In the weakening process of pollution, the inversion layer disappeared, the stratification was stable, and the vertical diffusion conditions turned better. The accumulation of local pollutants and external transmission under static and stable meteorological conditions were the main reason of the heavy pollution.
2022, 40(9): 44-53.
doi: 10.13205/j.hjgc.202209006
Abstract:
In order to study the pollution status of PM2.5 and PM10 in the atmosphere of Jiaozuo, Henan, based on the hourly observation data of PM2.5 and PM10 concentrations at 50 ambient air quality monitoring stations in Jiaozuo from 2018 to 2020, combined with meteorological data, the spatial and temporal distribution characteristics of PM2.5 and PM10 in Jiaozuo and the influence of meteorological factors were analyzed. The results showed that: 1) The diurnal variation of PM2.5 and PM10 concentrations presented a bimodal structure in all seasons. The variation curve of the overall monthly PM2.5 and PM10 concentrations in the three years was approximately U-shaped. The seasonal variation characteristics of PM2.5 and PM10 were higher in winter and low in summer, and moderate in spring and autumn. 2) The spatial characteristics of PM2.5 and PM10 concentrations were higher in southwestern regions and lower in northeastern regions. Compared with 2018, the decrease scopes of PM2.5 and PM10 concentrations in Xiuwu County in 2020 were the largest, which were 30.25% and 22.72%, respectively. 3) Spearman correlation analysis showed that the concentrations of PM2.5 and PM10 had significantly negative correlations with temperature and wind speed, and a significantly positive correlation with air pressure. Relative humidity had a significantly positive correlation with PM2.5 concentration, and a significantly negative correlation with PM10 concentration. The monitoring station in Environmental Protection Bureau of Jiaozuo had higher concentrations of PM2.5 and PM10 in northeast and southwest wind directions. The selected monitoring stations in surrounding counties(cities) of Jiaozuo had higher concentrations of PM2.5 and PM10 in the southwest wind direction, such as Qinghua Town in Boai County, Xiwan Town in Qinyang City and Qiaomiao Township in Wuzhi County. The study showed that there was a certain relationship between air pollution and meteorological factors in Jiaozuo from 2018 to 2020. It was expected to provide an important scientific basis for the prevention and control of air pollution in industrial areas, and the planning and layout of production and life in the future.
In order to study the pollution status of PM2.5 and PM10 in the atmosphere of Jiaozuo, Henan, based on the hourly observation data of PM2.5 and PM10 concentrations at 50 ambient air quality monitoring stations in Jiaozuo from 2018 to 2020, combined with meteorological data, the spatial and temporal distribution characteristics of PM2.5 and PM10 in Jiaozuo and the influence of meteorological factors were analyzed. The results showed that: 1) The diurnal variation of PM2.5 and PM10 concentrations presented a bimodal structure in all seasons. The variation curve of the overall monthly PM2.5 and PM10 concentrations in the three years was approximately U-shaped. The seasonal variation characteristics of PM2.5 and PM10 were higher in winter and low in summer, and moderate in spring and autumn. 2) The spatial characteristics of PM2.5 and PM10 concentrations were higher in southwestern regions and lower in northeastern regions. Compared with 2018, the decrease scopes of PM2.5 and PM10 concentrations in Xiuwu County in 2020 were the largest, which were 30.25% and 22.72%, respectively. 3) Spearman correlation analysis showed that the concentrations of PM2.5 and PM10 had significantly negative correlations with temperature and wind speed, and a significantly positive correlation with air pressure. Relative humidity had a significantly positive correlation with PM2.5 concentration, and a significantly negative correlation with PM10 concentration. The monitoring station in Environmental Protection Bureau of Jiaozuo had higher concentrations of PM2.5 and PM10 in northeast and southwest wind directions. The selected monitoring stations in surrounding counties(cities) of Jiaozuo had higher concentrations of PM2.5 and PM10 in the southwest wind direction, such as Qinghua Town in Boai County, Xiwan Town in Qinyang City and Qiaomiao Township in Wuzhi County. The study showed that there was a certain relationship between air pollution and meteorological factors in Jiaozuo from 2018 to 2020. It was expected to provide an important scientific basis for the prevention and control of air pollution in industrial areas, and the planning and layout of production and life in the future.
2022, 40(9): 54-62,172.
doi: 10.13205/j.hjgc.202209007
Abstract:
The organic compounds emitted from biomass burning are important precursors of atmospheric secondary organic aerosols, but relevant reaction parameters are still relatively lacking. This study selected four representative species, including resorcinol(RES), 4-ethylphenol(4-EP), eugenol(Eug) and 2,4,6-trimethylphenol(Trmp), and used the relative rate method to determine the second-order reaction rate constants of those species against oxidation by the hydroxyl radical in the atmospheric aqueous-phases(such as conditions of fog/cloud droplets), also estimated the liquid phase reaction life under actual atmospheric conditions. The kinetic constants(K) of the four precursors at 298 K, pH=5.4 were(7.68±0.04)×109 L/(mol·s),(18.12±0.56)×109 L/(mol·s),(23.11±0.60)×109 L/(mol·s) and(16.90±0.58)×109 L/(mol·s), respectively. The uncertainties of K values were 3.5%~12%. In addition, the K value at T=293 K and 288 K were also determined, and the values at 288 K were 22%~38% lower than those at 298 K, indicating that temperature had a significant influence on the bimolecular rate constants of those compounds. It was also found that when the precursor was consumed nearly half, the solution pH decreased, suggesting that a certain number of organic acids might be generated during oxidation. The atmospheric lifetimes calculated according to the CAPRAM 3.0 under different scenarios ranged from tens of seconds to tens of hours, indicating that the aqueous-phase oxidation of biomass burning emitted phenolic species had a considerable impact on the secondary organic aerosol formation.
The organic compounds emitted from biomass burning are important precursors of atmospheric secondary organic aerosols, but relevant reaction parameters are still relatively lacking. This study selected four representative species, including resorcinol(RES), 4-ethylphenol(4-EP), eugenol(Eug) and 2,4,6-trimethylphenol(Trmp), and used the relative rate method to determine the second-order reaction rate constants of those species against oxidation by the hydroxyl radical in the atmospheric aqueous-phases(such as conditions of fog/cloud droplets), also estimated the liquid phase reaction life under actual atmospheric conditions. The kinetic constants(K) of the four precursors at 298 K, pH=5.4 were(7.68±0.04)×109 L/(mol·s),(18.12±0.56)×109 L/(mol·s),(23.11±0.60)×109 L/(mol·s) and(16.90±0.58)×109 L/(mol·s), respectively. The uncertainties of K values were 3.5%~12%. In addition, the K value at T=293 K and 288 K were also determined, and the values at 288 K were 22%~38% lower than those at 298 K, indicating that temperature had a significant influence on the bimolecular rate constants of those compounds. It was also found that when the precursor was consumed nearly half, the solution pH decreased, suggesting that a certain number of organic acids might be generated during oxidation. The atmospheric lifetimes calculated according to the CAPRAM 3.0 under different scenarios ranged from tens of seconds to tens of hours, indicating that the aqueous-phase oxidation of biomass burning emitted phenolic species had a considerable impact on the secondary organic aerosol formation.
2022, 40(9): 63-68,117.
doi: 10.13205/j.hjgc.202209008
Abstract:
To achieve the deep denitrification effect of wastewater treatment plants, taking a sewage treatment plant in Taihu Lake Basin as an example, the biomass carbon source with derivatives of biomass waste as the main raw material was used as the electron donor for denitrification, and the denitrification effects of the anoxic tank and deep-bed filter were studied respectively. The changes in microbial community structure before and after the addition of carbon sources were also analyzed. The results showed that 1.67~1.73 mg/L nitrate could be removed, when the biomass carbon source dosage was 2.5~3.0 t/d, and the removal rate was about 52%~68%. Meanwhile, the deep bed filter consumed about 5.27 mg COD for every 1 mg NO3--N removal after adding biomass carbon source in the process of denitrification. Thus, the effluent TN was stable and met the discharge limit requirements of class Ⅰ and Ⅱ protected areas in the Discharge Standard of Main Water Pollutants for Municipal Wastewater Treatment Plant & Key Industries in Taihu Area(DB 32/1072—2018). Through 16 S rRNA gene sequence analysis, it was found that the dominant microbial phyla of hypoxic pools and deep-bed filters were Proteobacteria, Actinobacteria, Chloroflexi, and Bacteroidota. After adding biomass carbon source to deep-bed filter with different process conditions and growth environment, the dominant flora with denitrification function such as Thiothrix, Bacillus, Propionicicella, norank_f_Rhodocyclaceae and Terrimonas were more prominent and further effectively ensured the stable deep nitrogen removal performance of the system. At the same time, the adding of biomass carbon source indirectly reduced carbon dioxide emissions, which made a positive contribution to carbon emission reduction and carbon neutralization.
To achieve the deep denitrification effect of wastewater treatment plants, taking a sewage treatment plant in Taihu Lake Basin as an example, the biomass carbon source with derivatives of biomass waste as the main raw material was used as the electron donor for denitrification, and the denitrification effects of the anoxic tank and deep-bed filter were studied respectively. The changes in microbial community structure before and after the addition of carbon sources were also analyzed. The results showed that 1.67~1.73 mg/L nitrate could be removed, when the biomass carbon source dosage was 2.5~3.0 t/d, and the removal rate was about 52%~68%. Meanwhile, the deep bed filter consumed about 5.27 mg COD for every 1 mg NO3--N removal after adding biomass carbon source in the process of denitrification. Thus, the effluent TN was stable and met the discharge limit requirements of class Ⅰ and Ⅱ protected areas in the Discharge Standard of Main Water Pollutants for Municipal Wastewater Treatment Plant & Key Industries in Taihu Area(DB 32/1072—2018). Through 16 S rRNA gene sequence analysis, it was found that the dominant microbial phyla of hypoxic pools and deep-bed filters were Proteobacteria, Actinobacteria, Chloroflexi, and Bacteroidota. After adding biomass carbon source to deep-bed filter with different process conditions and growth environment, the dominant flora with denitrification function such as Thiothrix, Bacillus, Propionicicella, norank_f_Rhodocyclaceae and Terrimonas were more prominent and further effectively ensured the stable deep nitrogen removal performance of the system. At the same time, the adding of biomass carbon source indirectly reduced carbon dioxide emissions, which made a positive contribution to carbon emission reduction and carbon neutralization.
2022, 40(9): 69-73,191.
doi: 10.13205/j.hjgc.202209009
Abstract:
Compared with the traditional enhanced biological phosphorus removal(EBPR) process which achieves the enrichment and recovery of sludge phosphate through the flow process, the biofilm process can efficiently and synchronically remove and enrich phosphate in wastewater, thus has the potential to be applied to the mainstream process. Given the problem of high carbon source stimulation required for anaerobic phosphorus release by the biofilm process, the phosphorus storage of biofilm can be enhanced by optimizing the process conditions to strengthen the biofilm aerobic phosphorus uptake capacity, thus reducing the consumption of carbon source during anaerobic phosphorus release. In this paper, a biofilm sequencing batch reactor(BSBR) was used to investigate the response relationship between phosphorus storage and phosphorus concentration in the recovery tank under the addition of a low carbon source. The effects of dissolved oxygen, mixing strength and aerobic time on phosphate enhanced absorption were studied by orthogonal test. The results showed that when the temperature was(25±2) ℃ and the anaerobic external carbon source was(180±20) mg/L, the phosphorus concentration in the enrichment solution increased with the increase of phosphorus storage in the biofilm, up to 90.62 mg/L. Under the same phosphorus storage, the dissolved oxygen concentration increased from 2 mg/L to 8 mg/L, and the maximum phosphate absorption rate increased from 2.60 mg/(L·h) to 8.70 mg/(L·h). Orthogonal experiments showed that the order of influencing factors on phosphate enhanced absorption was dissolved oxygen>aerobic time>mixing intensity. When the dissolved oxygen concentration was 6 mg/L, the stirring speed was 200 r/min, and the aerobic time was 5 h, the phosphorus removal efficiency was up to 99.98%.
Compared with the traditional enhanced biological phosphorus removal(EBPR) process which achieves the enrichment and recovery of sludge phosphate through the flow process, the biofilm process can efficiently and synchronically remove and enrich phosphate in wastewater, thus has the potential to be applied to the mainstream process. Given the problem of high carbon source stimulation required for anaerobic phosphorus release by the biofilm process, the phosphorus storage of biofilm can be enhanced by optimizing the process conditions to strengthen the biofilm aerobic phosphorus uptake capacity, thus reducing the consumption of carbon source during anaerobic phosphorus release. In this paper, a biofilm sequencing batch reactor(BSBR) was used to investigate the response relationship between phosphorus storage and phosphorus concentration in the recovery tank under the addition of a low carbon source. The effects of dissolved oxygen, mixing strength and aerobic time on phosphate enhanced absorption were studied by orthogonal test. The results showed that when the temperature was(25±2) ℃ and the anaerobic external carbon source was(180±20) mg/L, the phosphorus concentration in the enrichment solution increased with the increase of phosphorus storage in the biofilm, up to 90.62 mg/L. Under the same phosphorus storage, the dissolved oxygen concentration increased from 2 mg/L to 8 mg/L, and the maximum phosphate absorption rate increased from 2.60 mg/(L·h) to 8.70 mg/(L·h). Orthogonal experiments showed that the order of influencing factors on phosphate enhanced absorption was dissolved oxygen>aerobic time>mixing intensity. When the dissolved oxygen concentration was 6 mg/L, the stirring speed was 200 r/min, and the aerobic time was 5 h, the phosphorus removal efficiency was up to 99.98%.
2022, 40(9): 74-80,134.
doi: 10.13205/j.hjgc.202209010
Abstract:
This paper used iron nanoparticles(nFe) and ultrasound(US) to activate persulfate(PS), then explored the removal efficiencies of PS, nFe/PS and US/PS in pre-oxidation processes on antibiotic resistance genes(ARGs) and dissolved organic matter(DOC) in secondary effluent, and discussed their removal mechanisms. The results showed that the optimal dosages of PS, nFe and US were determined to be 4 mmol/L, 2 mmol/L and 40 kHz, respectively. After PS, nFe/PS and US/PS pre-oxidation reactions, concentrations of ARGs(tetA, tetC, sulⅠ, sulⅡ), intⅠ1 and 16 S rRNA were 104.38~106.82, 104.02~105.97 and 104.02~106.98, respectively. Under the optimal reaction conditions, the removal rates of DOC were 11.2%, 17.2% and 15.3%, respectively. Among them, nFe/PS had the best removal effect on the above-mentioned ARGs and DOC. In the three pre-oxidation processes, OH· and SO4-· all participated in the reaction. Compared with PS alone and US/PS combined processes, the content of OH· and SO4-· generated was the highest in the pre-oxidation of nFe/PS, and the concentration of SO4-· was the highest in the reaction system. Therefore, the nFe/PS pre-oxidation method could be used as a subsequent treatment to effectively remove ARGs and DOC in the secondary effluent.
This paper used iron nanoparticles(nFe) and ultrasound(US) to activate persulfate(PS), then explored the removal efficiencies of PS, nFe/PS and US/PS in pre-oxidation processes on antibiotic resistance genes(ARGs) and dissolved organic matter(DOC) in secondary effluent, and discussed their removal mechanisms. The results showed that the optimal dosages of PS, nFe and US were determined to be 4 mmol/L, 2 mmol/L and 40 kHz, respectively. After PS, nFe/PS and US/PS pre-oxidation reactions, concentrations of ARGs(tetA, tetC, sulⅠ, sulⅡ), intⅠ1 and 16 S rRNA were 104.38~106.82, 104.02~105.97 and 104.02~106.98, respectively. Under the optimal reaction conditions, the removal rates of DOC were 11.2%, 17.2% and 15.3%, respectively. Among them, nFe/PS had the best removal effect on the above-mentioned ARGs and DOC. In the three pre-oxidation processes, OH· and SO4-· all participated in the reaction. Compared with PS alone and US/PS combined processes, the content of OH· and SO4-· generated was the highest in the pre-oxidation of nFe/PS, and the concentration of SO4-· was the highest in the reaction system. Therefore, the nFe/PS pre-oxidation method could be used as a subsequent treatment to effectively remove ARGs and DOC in the secondary effluent.
2022, 40(9): 81-88,142.
doi: 10.13205/j.hjgc.202209011
Abstract:
Grasping the characteristics and sources of non-point source pollution load in the Gansu section of the Yellow River Basin is an important basis for improving the level of water pollution control on a regional scale. Based on the DPeRS model, this study selected four pollution indicators of total nitrogen, total phosphorus, ammonia nitrogen and chemical oxygen demand, from the five major pollution types, farmland runoff, urban runoff, livestock and poultry breeding, rural life, and soil erosion. Pollution load estimation, pollution source analysis and spatial distribution analysis were carried out on non-point source pollution of nine cities(prefectures) and 58 districts(counties). The results showed that: from the model estimation results, the average non-point source pollution load of total nitrogen, total phosphorus, ammonia nitrogen and chemical oxygen demand in the entire basin in 2018 was 65.6,11.8,19.1, 77.2 kg/km2. From the regional scale analysis, the area with the highest non-point source pollution load of total nitrogen and total phosphorus in the Yellow River Basin of Gansu was Anning District, Lanzhou, which accounted for 10.83% and 5.16% of the total load of the entire basin respectively; the area with the highest non-point source pollution load of ammonia nitrogen and chemical oxygen demand was Linxia City in Linxia Prefecture, respectively, accounted for 26.23% and 56.56% of the total load of the entire basin. From the analysis of pollution sources, the primary pollution sources of total nitrogen, total phosphorus, ammonia nitrogen and chemical oxygen demand were farmland runoff, soil erosion, farmland runoff, and livestock and poultry farming. From the spatial distribution analysis, the total non-point source pollution load of each district(county) of the Yellow River Basin presented a distribution characteristic of middle-high and low sides. The areas with heavier pollution load were mainly concentrated in local areas such as the Lanzhou section of the Yellow River, the Linxia section of the Daxia River, and the Tianshui section of the Weihe River.
Grasping the characteristics and sources of non-point source pollution load in the Gansu section of the Yellow River Basin is an important basis for improving the level of water pollution control on a regional scale. Based on the DPeRS model, this study selected four pollution indicators of total nitrogen, total phosphorus, ammonia nitrogen and chemical oxygen demand, from the five major pollution types, farmland runoff, urban runoff, livestock and poultry breeding, rural life, and soil erosion. Pollution load estimation, pollution source analysis and spatial distribution analysis were carried out on non-point source pollution of nine cities(prefectures) and 58 districts(counties). The results showed that: from the model estimation results, the average non-point source pollution load of total nitrogen, total phosphorus, ammonia nitrogen and chemical oxygen demand in the entire basin in 2018 was 65.6,11.8,19.1, 77.2 kg/km2. From the regional scale analysis, the area with the highest non-point source pollution load of total nitrogen and total phosphorus in the Yellow River Basin of Gansu was Anning District, Lanzhou, which accounted for 10.83% and 5.16% of the total load of the entire basin respectively; the area with the highest non-point source pollution load of ammonia nitrogen and chemical oxygen demand was Linxia City in Linxia Prefecture, respectively, accounted for 26.23% and 56.56% of the total load of the entire basin. From the analysis of pollution sources, the primary pollution sources of total nitrogen, total phosphorus, ammonia nitrogen and chemical oxygen demand were farmland runoff, soil erosion, farmland runoff, and livestock and poultry farming. From the spatial distribution analysis, the total non-point source pollution load of each district(county) of the Yellow River Basin presented a distribution characteristic of middle-high and low sides. The areas with heavier pollution load were mainly concentrated in local areas such as the Lanzhou section of the Yellow River, the Linxia section of the Daxia River, and the Tianshui section of the Weihe River.
2022, 40(9): 89-95.
doi: 10.13205/j.hjgc.202209012
Abstract:
The differences in COD, TP removal rate and sludge yield in different heterogeneous Fenton catalysts for treating high concentration organophosphorus groundwater pumped from pesticide-contaminated sites were compared, and the influences of H2O2 dosage, heterogeneous catalyst loading and pH on the reaction efficiency were investigated. The surface structure and composition of heterogeneous catalysts before and after the reaction were analyzed using scanning electron microscope(SEM) and X-ray energy spectrum(EDS). The results indicated that Fe2O3/Al2O3 heterogeneous catalyst had a higher specific surface area and Fe content at load, and Fe was deposited on the surface of the material after the reaction. In heterogeneous Fenton reaction with Fe2O3/Al2O3, Al2O3 and Fe2O3/SiO2-Al2O3 as catalysts, the removal rates of COD and TP can reach 84.72%, 74.10%, 75.98% and 88.48%, 82.80%, 85.83%, respectively. Higher than homogeneous Fenton reaction without solid catalyst. In the range of ρ(H2O2)/ρ(COD)=0.5~2.0, the removal rates of COD and TP significantly increased with the increase of H2O2 dosage, and the removal rates of COD and TP were in direct proportion to the loading amount of heterogeneous catalysts. At the same time, the addition of heterogeneous catalyst can significantly reduce the sludge yield and expand the effective pH range of the reaction system.
The differences in COD, TP removal rate and sludge yield in different heterogeneous Fenton catalysts for treating high concentration organophosphorus groundwater pumped from pesticide-contaminated sites were compared, and the influences of H2O2 dosage, heterogeneous catalyst loading and pH on the reaction efficiency were investigated. The surface structure and composition of heterogeneous catalysts before and after the reaction were analyzed using scanning electron microscope(SEM) and X-ray energy spectrum(EDS). The results indicated that Fe2O3/Al2O3 heterogeneous catalyst had a higher specific surface area and Fe content at load, and Fe was deposited on the surface of the material after the reaction. In heterogeneous Fenton reaction with Fe2O3/Al2O3, Al2O3 and Fe2O3/SiO2-Al2O3 as catalysts, the removal rates of COD and TP can reach 84.72%, 74.10%, 75.98% and 88.48%, 82.80%, 85.83%, respectively. Higher than homogeneous Fenton reaction without solid catalyst. In the range of ρ(H2O2)/ρ(COD)=0.5~2.0, the removal rates of COD and TP significantly increased with the increase of H2O2 dosage, and the removal rates of COD and TP were in direct proportion to the loading amount of heterogeneous catalysts. At the same time, the addition of heterogeneous catalyst can significantly reduce the sludge yield and expand the effective pH range of the reaction system.
2022, 40(9): 96-100.
doi: 10.13205/j.hjgc.202209013
Abstract:
The pumping test is carried out in a riverside well field along the Harbin section of the Songhua River. The recharge ratio of surface water infiltration of a riverside well field was estimated by using hydrodynamic analytical method, and environmental tracing method, and its changes during pumping were analyzed. The results showed that the recharge ratio of surface water increased with the decrease of groundwater level when pumping in the riverside well field, and tended to be stable after the flow field got stable. When the groundwater level in the study area was stable, it was estimated that the surface water captured by pumping accounted for about 60% of the yield by the two methods, and the two methods supported each other. The storage function of the riverside well field was obvious. The pumping impact on surface water was small, and the safety and stability of surface water wouldn't not be affected. The research can provide decision support and practical reference for the construction of riverside well fields along the Songhua River with similar conditions.
The pumping test is carried out in a riverside well field along the Harbin section of the Songhua River. The recharge ratio of surface water infiltration of a riverside well field was estimated by using hydrodynamic analytical method, and environmental tracing method, and its changes during pumping were analyzed. The results showed that the recharge ratio of surface water increased with the decrease of groundwater level when pumping in the riverside well field, and tended to be stable after the flow field got stable. When the groundwater level in the study area was stable, it was estimated that the surface water captured by pumping accounted for about 60% of the yield by the two methods, and the two methods supported each other. The storage function of the riverside well field was obvious. The pumping impact on surface water was small, and the safety and stability of surface water wouldn't not be affected. The research can provide decision support and practical reference for the construction of riverside well fields along the Songhua River with similar conditions.
2022, 40(9): 101-107.
doi: 10.13205/j.hjgc.202209014
Abstract:
In this paper, rainfall data in 126 meteorological stations from 1960 to 2020 over the Yangtze River basin were chosen to explore spatial and temporal patterns of rainy-season features(i.e., onset, retreat, and rainy-season precipitation). The multi-scale moving t-test was used to capture the onset and retreat of the rainy season in different stations. Furthermore, the teleconnections between seas surface temperature and rainy-season features were calculated to explore the underlying causes of the variability of rainy-season features.Resultsshowed that onset, retreat, and rainy-season precipitation had prominent characteristics of inter-decadal and spatial changes. In terms of spatial patterns, onset, retreat, and rainy-season precipitation changed from southeast to northwest. The temporal regular of rainy-season features from 1960 to 2020 was explored. The Pettitt test was applied to detect the abruption point of rainy-season characteristics. It showed that the abruption points of rainy-season features were related to ENSO events. Furthermore, rainy-season features were related to ENSO and anti-cyclone in the northern Pacific Ocean. Warmer sea surface temperature would cause a later onset, earlier retreat, and less rainfall, which played a crucial role in water management in the Yangtze River basin.
In this paper, rainfall data in 126 meteorological stations from 1960 to 2020 over the Yangtze River basin were chosen to explore spatial and temporal patterns of rainy-season features(i.e., onset, retreat, and rainy-season precipitation). The multi-scale moving t-test was used to capture the onset and retreat of the rainy season in different stations. Furthermore, the teleconnections between seas surface temperature and rainy-season features were calculated to explore the underlying causes of the variability of rainy-season features.Resultsshowed that onset, retreat, and rainy-season precipitation had prominent characteristics of inter-decadal and spatial changes. In terms of spatial patterns, onset, retreat, and rainy-season precipitation changed from southeast to northwest. The temporal regular of rainy-season features from 1960 to 2020 was explored. The Pettitt test was applied to detect the abruption point of rainy-season characteristics. It showed that the abruption points of rainy-season features were related to ENSO events. Furthermore, rainy-season features were related to ENSO and anti-cyclone in the northern Pacific Ocean. Warmer sea surface temperature would cause a later onset, earlier retreat, and less rainfall, which played a crucial role in water management in the Yangtze River basin.
2022, 40(9): 108-117.
doi: 10.13205/j.hjgc.202209015
Abstract:
Biofuel ash(BFA) was modified by alkali melting combined with hydrothermal method, and generated geopolymer-zeolite composition. XRD, SEM, and FTIR were carried out to characterize biofuel ash before and after modification, and the adsorption characteristics of modified BFA(MBFA) for Cd2+, Zn2+, Cu2+, Pb2+ were studied. The result indicated that the specific surface area and pore volume of modified biofuel ash were enhanced obviously. Both the pseudo-first-order kinetics and the pseudo-second-order kinetic models could well describe the adsorption process of MBFA for Cd2+, Zn2+, Cu2+, and Pb2+(R2>0.9375), indicating the existence of both physical and chemical adsorption. At 298 K, both the Langmuir equation and Freundlich equation reached a high fitting degree(0.9223≤R2≤0.9982) for Cd2+, Zn2+, Cu2+, but for Pb2+, Langmuir equation were better. According to the fitting results of the Langmuir model, the adsorption capacity of modified biofuel ash of Cd2+, Zn2+, Cu2+ and Pb2+ in single heavy metal ion solution was 71.26, 53.52, 54.05, 279.48 mg/g, respectively, which were higher than most similar adsorbents. The adsorption of the heavy metal ions onto MBFA was disturbed by coexisting metal ions, and in mixed solution the selective adsorption of heavy metal ions by MBFA was in the order of Pb2+>Cu2+>Cd2+>Zn2+.
Biofuel ash(BFA) was modified by alkali melting combined with hydrothermal method, and generated geopolymer-zeolite composition. XRD, SEM, and FTIR were carried out to characterize biofuel ash before and after modification, and the adsorption characteristics of modified BFA(MBFA) for Cd2+, Zn2+, Cu2+, Pb2+ were studied. The result indicated that the specific surface area and pore volume of modified biofuel ash were enhanced obviously. Both the pseudo-first-order kinetics and the pseudo-second-order kinetic models could well describe the adsorption process of MBFA for Cd2+, Zn2+, Cu2+, and Pb2+(R2>0.9375), indicating the existence of both physical and chemical adsorption. At 298 K, both the Langmuir equation and Freundlich equation reached a high fitting degree(0.9223≤R2≤0.9982) for Cd2+, Zn2+, Cu2+, but for Pb2+, Langmuir equation were better. According to the fitting results of the Langmuir model, the adsorption capacity of modified biofuel ash of Cd2+, Zn2+, Cu2+ and Pb2+ in single heavy metal ion solution was 71.26, 53.52, 54.05, 279.48 mg/g, respectively, which were higher than most similar adsorbents. The adsorption of the heavy metal ions onto MBFA was disturbed by coexisting metal ions, and in mixed solution the selective adsorption of heavy metal ions by MBFA was in the order of Pb2+>Cu2+>Cd2+>Zn2+.
2022, 40(9): 118-125.
doi: 10.13205/j.hjgc.202209016
Abstract:
Permeable pavement has become the key development direction of urban road pavement in the future because of its functions of rainwater infiltration and purification. The impact mechanism and factors of resource and environment impact in its life cycle need to be systematically and comprehensively analyzed. Based on the rainfall characteristics and pavement engineering practice in Beijing, this paper comprehensively analyzed the environmental impact of permeable cement concrete pavement in the whole life cycle with the life cycle assessment(LCA). Combined with the stormwater management model(SWMM), this paper simulated the environmental benefits of permeable pavement in the use stage, and compared the changes brought by different maintenance methods to the environmental impact of permeable cement concrete pavement. The results showed that the input of cement in the production stage was the main factor causing the environmental impact in its life cycle. The environmental benefits provided by rainwater infiltration and purification in the use stage could offset the environmental impact in other stages. From the environmental perspective, daily cleaning+high-pressure washing was the best available maintenance method for permeable cement concrete pavement. However, the service life should be taken into consideration to select the most suitable maintenance method, for the best environmental performance of the permeable pavement. Therefore, the coupling application of LCA and SWMM could more accurately quantify the environmental benefits and key influencing factors of permeable pavement in the whole life cycle. This method was expected to be applied to the systematic evaluation of resource and environmental impact of other LID facilities and even the whole sponge city.
Permeable pavement has become the key development direction of urban road pavement in the future because of its functions of rainwater infiltration and purification. The impact mechanism and factors of resource and environment impact in its life cycle need to be systematically and comprehensively analyzed. Based on the rainfall characteristics and pavement engineering practice in Beijing, this paper comprehensively analyzed the environmental impact of permeable cement concrete pavement in the whole life cycle with the life cycle assessment(LCA). Combined with the stormwater management model(SWMM), this paper simulated the environmental benefits of permeable pavement in the use stage, and compared the changes brought by different maintenance methods to the environmental impact of permeable cement concrete pavement. The results showed that the input of cement in the production stage was the main factor causing the environmental impact in its life cycle. The environmental benefits provided by rainwater infiltration and purification in the use stage could offset the environmental impact in other stages. From the environmental perspective, daily cleaning+high-pressure washing was the best available maintenance method for permeable cement concrete pavement. However, the service life should be taken into consideration to select the most suitable maintenance method, for the best environmental performance of the permeable pavement. Therefore, the coupling application of LCA and SWMM could more accurately quantify the environmental benefits and key influencing factors of permeable pavement in the whole life cycle. This method was expected to be applied to the systematic evaluation of resource and environmental impact of other LID facilities and even the whole sponge city.
REVIEW ON SPATIAL-TEMPORAL DISTRIBUTION CHARACTERISTICS OF MUNICIPAL SOLID WASTE COMPONENTS IN CHINA
2022, 40(9): 126-134.
doi: 10.13205/j.hjgc.202209017
Abstract:
The components of municipal solid waste(MSW) is the basis for selecting disposal methods, which are closely related to regions, seasons and residents' living habits. This paper systematically reviews the temporal and spatial distribution characteristics of MSW in China in recent years. In recent 20 years, kitchen waste accounts for the highest proportion(close to or even more than 50%) in urban MSW of China, the proportion of recyclables increased(from about 22% to about 30%), and the low heating value of MSW shows an upward trend(more than 6000 kJ/kg). Kitchen waste accounts for a high proportion of MSW in the first quarter of a year(about 61% in cities), and in the third and fourth quarters, the proportion of ash and soil increases(up to 29% in rural areas) with lower moisture content and higher heating value(up to 6600 kJ/kg in cities). Nationwide, there are significant differences in the proportion of MSW in various regions. The proportion of kitchen waste decreases from the east(65%) to the west(50%), the proportion of recyclables decreases from the south(25%) to the north(17%), and that of ash and soil decreases from the north(27%) to the south(11%). The heat value of MSW is positively correlated with the level of the region's economic development. The conclusion can provide data support for the treatment of MSW according to local conditions.
The components of municipal solid waste(MSW) is the basis for selecting disposal methods, which are closely related to regions, seasons and residents' living habits. This paper systematically reviews the temporal and spatial distribution characteristics of MSW in China in recent years. In recent 20 years, kitchen waste accounts for the highest proportion(close to or even more than 50%) in urban MSW of China, the proportion of recyclables increased(from about 22% to about 30%), and the low heating value of MSW shows an upward trend(more than 6000 kJ/kg). Kitchen waste accounts for a high proportion of MSW in the first quarter of a year(about 61% in cities), and in the third and fourth quarters, the proportion of ash and soil increases(up to 29% in rural areas) with lower moisture content and higher heating value(up to 6600 kJ/kg in cities). Nationwide, there are significant differences in the proportion of MSW in various regions. The proportion of kitchen waste decreases from the east(65%) to the west(50%), the proportion of recyclables decreases from the south(25%) to the north(17%), and that of ash and soil decreases from the north(27%) to the south(11%). The heat value of MSW is positively correlated with the level of the region's economic development. The conclusion can provide data support for the treatment of MSW according to local conditions.
2022, 40(9): 135-142.
doi: 10.13205/j.hjgc.202209018
Abstract:
Many factors affect the emission concentration and composition of volatile organic compounds in the catering industry. Used the method of controlling a single variable on the catering experimental platform, the effects of the types of edible oils, cooking methods, and types of ingredients on the emission characteristics of non-methane total hydrocarbons(NMHC), non-methane volatile organic compounds(NMVOCs) and aldehydes and ketones in the cooking process of catering were studied. The results showed that the concentration of NMVOCs produced by cooking with corn oil was as low as 434 μg/m3, and that's only 1/10 of the blended oil. The NMVOCs produced by corn oil had the least kinds of components, and the risk of carcinogenesis was lower than that of blended oils and shortenings. The cooking method of deep-frying produced more NMVOCs and aldehydes and ketone compounds than those of stir-frying. The types and quantities of NMVOCs produced by cooking meat ingredients were more than those of vegetable ingredcents in the same way.
Many factors affect the emission concentration and composition of volatile organic compounds in the catering industry. Used the method of controlling a single variable on the catering experimental platform, the effects of the types of edible oils, cooking methods, and types of ingredients on the emission characteristics of non-methane total hydrocarbons(NMHC), non-methane volatile organic compounds(NMVOCs) and aldehydes and ketones in the cooking process of catering were studied. The results showed that the concentration of NMVOCs produced by cooking with corn oil was as low as 434 μg/m3, and that's only 1/10 of the blended oil. The NMVOCs produced by corn oil had the least kinds of components, and the risk of carcinogenesis was lower than that of blended oils and shortenings. The cooking method of deep-frying produced more NMVOCs and aldehydes and ketone compounds than those of stir-frying. The types and quantities of NMVOCs produced by cooking meat ingredients were more than those of vegetable ingredcents in the same way.
2022, 40(9): 143-149,157.
doi: 10.13205/j.hjgc.202209019
Abstract:
In order to find efficient stabilization materials for cadmium contaminated soil in Northeast China, the sulfhydryl biochar was prepared with corn stalk biochar as the raw material and(3-Mercaptopropyl) trimethoxysilane(MPS) as the modifier. Furthermore, the effects of different amounts(1%, 3%, 5%) of sulfhydryl biochar, biochar and lime on soil physical and chemical properties(pH value, CEC value, SOC value), leaching content of heavy metal cadmium TCLP and chemical form of cadmium were analyzed. The results showed that the cadmium leaching content of the TCLP method was 109.82, 96.35, 86.34 mg/kg under different dosage conditions of original biochar, which was inferior to that of lime treatment under the same dosage conditions. Each amount of sulfhydryl biochar decreased soil pH value, increased CEC value, and increased SOC value. The cadmium stabilization effect of 5% thiol biochar was the most obvious, and the cadmium leaching content of the TCLP method was 67.53 mg/kg, which was 11.1% lower than that of 5% lime treatment. The results showed that the pH value of soil decreased, CEC value increased and SOC value increased with each dosage of sulfhydryl biochar. The cadmium leaching content of TCLP method was 76.99 mg/kg, 72.52 mg/kg and 67.53 mg/kg, respectively, and the effect was better than that of lime under the same dosage condition. The cadmium stabilization effect of 5% thiol biochar was the most significant, and the cadmium leaching content was 11.1% lower than that of 5% lime. The results of BCR continuous extraction showed that the amount of 5% sulfhydryl biochar reduced the soluble cadmium and reducible cadmium of weak acid by 35.8% and 17.63%, respectively, which were 8.18% and 5.7% higher than that of 5% lime treatment. The results showed that thiol biochar had a better stabilization effect than lime on cadmium-contaminated soil in northeast China.
In order to find efficient stabilization materials for cadmium contaminated soil in Northeast China, the sulfhydryl biochar was prepared with corn stalk biochar as the raw material and(3-Mercaptopropyl) trimethoxysilane(MPS) as the modifier. Furthermore, the effects of different amounts(1%, 3%, 5%) of sulfhydryl biochar, biochar and lime on soil physical and chemical properties(pH value, CEC value, SOC value), leaching content of heavy metal cadmium TCLP and chemical form of cadmium were analyzed. The results showed that the cadmium leaching content of the TCLP method was 109.82, 96.35, 86.34 mg/kg under different dosage conditions of original biochar, which was inferior to that of lime treatment under the same dosage conditions. Each amount of sulfhydryl biochar decreased soil pH value, increased CEC value, and increased SOC value. The cadmium stabilization effect of 5% thiol biochar was the most obvious, and the cadmium leaching content of the TCLP method was 67.53 mg/kg, which was 11.1% lower than that of 5% lime treatment. The results showed that the pH value of soil decreased, CEC value increased and SOC value increased with each dosage of sulfhydryl biochar. The cadmium leaching content of TCLP method was 76.99 mg/kg, 72.52 mg/kg and 67.53 mg/kg, respectively, and the effect was better than that of lime under the same dosage condition. The cadmium stabilization effect of 5% thiol biochar was the most significant, and the cadmium leaching content was 11.1% lower than that of 5% lime. The results of BCR continuous extraction showed that the amount of 5% sulfhydryl biochar reduced the soluble cadmium and reducible cadmium of weak acid by 35.8% and 17.63%, respectively, which were 8.18% and 5.7% higher than that of 5% lime treatment. The results showed that thiol biochar had a better stabilization effect than lime on cadmium-contaminated soil in northeast China.
2022, 40(9): 150-157.
doi: 10.13205/j.hjgc.202209020
Abstract:
Simultaneously producing hydrogen and methane via sewage sludge and food waste anaerobic co-digestion, widely regarded as one of the promising methods for renewable energy, plays an important role in carbon emission reduction. This study explored the effect of different initial pH values on the methane production from the residue from anaerobic co-fermentative hydrogen production of sewage sludge and food waste through batch experiments under thermophilic operation(55±1)℃. The results showed that properly increasing the alkalinity of the initial substrate of residue from hydrogen production improved methanogenic performance, while the initial pH=6 inhibited methane production. The highest value of maximum methane concentration(79.08%), cumulative methane yield(101 mL/g DS), and maximum methane production rate(12.21 mL/d) were all found in the test group of initial pH=8. The degradation ratios of total carbohydrate and total protein with different initial pH values were positively correlated with the cumulative methane yield. And total carbohydrate and total protein degradation were also the highest at initial pH=8, with values of 6078 mg/L~55.70% and 4710 mg/L~69.67%, respectively. Among these, the degradation rate of total protein was higher than total carbohydrate. Meanwhile, the pH value after digestion from different initial pH values tended to be 7.5 or so.
Simultaneously producing hydrogen and methane via sewage sludge and food waste anaerobic co-digestion, widely regarded as one of the promising methods for renewable energy, plays an important role in carbon emission reduction. This study explored the effect of different initial pH values on the methane production from the residue from anaerobic co-fermentative hydrogen production of sewage sludge and food waste through batch experiments under thermophilic operation(55±1)℃. The results showed that properly increasing the alkalinity of the initial substrate of residue from hydrogen production improved methanogenic performance, while the initial pH=6 inhibited methane production. The highest value of maximum methane concentration(79.08%), cumulative methane yield(101 mL/g DS), and maximum methane production rate(12.21 mL/d) were all found in the test group of initial pH=8. The degradation ratios of total carbohydrate and total protein with different initial pH values were positively correlated with the cumulative methane yield. And total carbohydrate and total protein degradation were also the highest at initial pH=8, with values of 6078 mg/L~55.70% and 4710 mg/L~69.67%, respectively. Among these, the degradation rate of total protein was higher than total carbohydrate. Meanwhile, the pH value after digestion from different initial pH values tended to be 7.5 or so.
2022, 40(9): 158-166.
doi: 10.13205/j.hjgc.202209021
Abstract:
Soil covering has been used to isolate coal gangue from oxygen, and it can rapidly remediate coal gangue waste. However, the coal gangue which has long-term piled can release heavy metals under the rain leaching and groundwater soaking, which will diffuse to the surrounding soil with water flow. Meanwhile, the released heavy metals will also migrate to the upper covering soil under the action of soil capillarity and plant root activity, therefore impact soil quality. We chose a coal gangue hill in Ningdong, Ningxia as the research object, and analyzed the spatial distribution characteristics of Cu, Zn, Pb, Cr, Cd, As, Mn, and Ni in the covering soil at different depths of the coal gangue hill and the surrounding soil within 0~200 m distance from the coal gangue hill. We also explored the status quo of soil environmental quality, and comprehensively assessed the potential ecological risks of soils. The results showed that Cr was the main pollutant in the study area. Cr content in the covering soils was higher than the control in 86.36% of the sampling sites, and Cr content was higher than that of the soil background value of the control point in 100% and 50% of the sampling sites of the surrounding surface soil and deep soil, respectively. Toxic heavy metals in coal gangue migrated to the covering soil to a certain extent, and the heavy metals in the soil directly contacting with coal gangue layer were enriched obviously. The coal gangue dust diffusion is the main way to enrich heavy metals in the surrounding soil, and its significant influence range was within 10 m of the gangue hill. The potential ecological risk index(RI) of soils around the coal gangue hill ranged from 40.80~63.31, indicating that the pollution extent was all slight. RI value of the covering soil was between 44.83~70.54, and the pollution extent was of only one sampling point reached the medium level.
Soil covering has been used to isolate coal gangue from oxygen, and it can rapidly remediate coal gangue waste. However, the coal gangue which has long-term piled can release heavy metals under the rain leaching and groundwater soaking, which will diffuse to the surrounding soil with water flow. Meanwhile, the released heavy metals will also migrate to the upper covering soil under the action of soil capillarity and plant root activity, therefore impact soil quality. We chose a coal gangue hill in Ningdong, Ningxia as the research object, and analyzed the spatial distribution characteristics of Cu, Zn, Pb, Cr, Cd, As, Mn, and Ni in the covering soil at different depths of the coal gangue hill and the surrounding soil within 0~200 m distance from the coal gangue hill. We also explored the status quo of soil environmental quality, and comprehensively assessed the potential ecological risks of soils. The results showed that Cr was the main pollutant in the study area. Cr content in the covering soils was higher than the control in 86.36% of the sampling sites, and Cr content was higher than that of the soil background value of the control point in 100% and 50% of the sampling sites of the surrounding surface soil and deep soil, respectively. Toxic heavy metals in coal gangue migrated to the covering soil to a certain extent, and the heavy metals in the soil directly contacting with coal gangue layer were enriched obviously. The coal gangue dust diffusion is the main way to enrich heavy metals in the surrounding soil, and its significant influence range was within 10 m of the gangue hill. The potential ecological risk index(RI) of soils around the coal gangue hill ranged from 40.80~63.31, indicating that the pollution extent was all slight. RI value of the covering soil was between 44.83~70.54, and the pollution extent was of only one sampling point reached the medium level.
2022, 40(9): 167-172.
doi: 10.13205/j.hjgc.202209022
Abstract:
The properties of crude oil will directly affect the selection of polluted soil remediation technology. Paraffin and naphthenic based crude oil contaminated soils were selected, and the coupling technology of soil washing and thermal desorption were adopted to investigate the desorption ratios of petroleum and energy consumption. The particular concern was focused on the screening effect of washing pretreatment on soil particle size, desorption rate of petroleum pollutants, the effect of thermal desorption remediation on reagent washed soil, etc. The results showed that after water washing pretreatment, the desorption rate of petroleum adsorbed by large particle size sand in soil was about 59.83% and 36.42%, much higher than the clay component. Anionic sodium α-16 olefin sulfonate and isomeric alcohol ethoxylate were used during washing process. The desorption rates of petroleum in paraffin based and naphthenic crude oil contaminated soil were 46.5% and 39.8% respectively. Anionic sodium α-16 olefin sulfonate had a stronger desorption ability. Naphthenic based crude oil contaminated soil was remediated by thermal desorption, the desorption time of clay component after washing was shorter than the raw contaminated soil. The content of petroleum was decreased to 0.26% after thermal desorption at 400 ℃ for 3 hours. The washing-thermal desorption coupling technology was adopted for field test, and the petroleum content of large particle size sand after washing was 1.56%, and 0.57% for the dewatered clay by thermal desorption. The energy consumption of washing-thermal desorption was lower than the single thermal desorption technology.
The properties of crude oil will directly affect the selection of polluted soil remediation technology. Paraffin and naphthenic based crude oil contaminated soils were selected, and the coupling technology of soil washing and thermal desorption were adopted to investigate the desorption ratios of petroleum and energy consumption. The particular concern was focused on the screening effect of washing pretreatment on soil particle size, desorption rate of petroleum pollutants, the effect of thermal desorption remediation on reagent washed soil, etc. The results showed that after water washing pretreatment, the desorption rate of petroleum adsorbed by large particle size sand in soil was about 59.83% and 36.42%, much higher than the clay component. Anionic sodium α-16 olefin sulfonate and isomeric alcohol ethoxylate were used during washing process. The desorption rates of petroleum in paraffin based and naphthenic crude oil contaminated soil were 46.5% and 39.8% respectively. Anionic sodium α-16 olefin sulfonate had a stronger desorption ability. Naphthenic based crude oil contaminated soil was remediated by thermal desorption, the desorption time of clay component after washing was shorter than the raw contaminated soil. The content of petroleum was decreased to 0.26% after thermal desorption at 400 ℃ for 3 hours. The washing-thermal desorption coupling technology was adopted for field test, and the petroleum content of large particle size sand after washing was 1.56%, and 0.57% for the dewatered clay by thermal desorption. The energy consumption of washing-thermal desorption was lower than the single thermal desorption technology.
2022, 40(9): 173-177,232.
doi: 10.13205/j.hjgc.202209023
Abstract:
An accurate and quantitative identification of anthropogenic heavy metal sources in farmland soil is vital for the subsequent implementation of more precise prevention and control. In this study, soil samples were collected from a typical agricultural area, and the anthropogenic sources of heavy metals in the surface soils were quantitatively identified by using the enrichment factor(EF) and multiple linear regression of absolute principal component scores(MLR-APCS) model.Resultsshowed that heavy metals like Pb, Cu, Zn, Cr and Ni in the surface soil have been affected by anthropogenic sources to different extents. The average increases rates in Pb, Cu, Zn, Cr and Ni were 112.37%, 71.21%, 59.38%, 69.67% and 64.54% respectively, when comparing their total contents in the surface soils with the contents in the local background soils. The EF values of heavy metals decreased with the order of Pb, Cu, Cr, Ni and Zn. Among them, Pb reached a medium enrichment level, and its anthropogenic content was more than 50% of the total content. Based on the anthropogenic heavy metal contents, atmospheric deposition and livestock manure were identified as the two main anthropogenic heavy metal sources. The MLR-APCS simulation results showed that atmospheric deposition could contribute on average 42.41%, 37.58% and 37.26% of total Pb, Cr and Ni contents, respectively, while livestock manure contributed 41.67% of total Cu and 39.39% of total Zn contents. In general, this study provided a reliable method for quantitative identification of anthropogenic heavy metal sources in farmland soil, which can be applied in other similar areas.
An accurate and quantitative identification of anthropogenic heavy metal sources in farmland soil is vital for the subsequent implementation of more precise prevention and control. In this study, soil samples were collected from a typical agricultural area, and the anthropogenic sources of heavy metals in the surface soils were quantitatively identified by using the enrichment factor(EF) and multiple linear regression of absolute principal component scores(MLR-APCS) model.Resultsshowed that heavy metals like Pb, Cu, Zn, Cr and Ni in the surface soil have been affected by anthropogenic sources to different extents. The average increases rates in Pb, Cu, Zn, Cr and Ni were 112.37%, 71.21%, 59.38%, 69.67% and 64.54% respectively, when comparing their total contents in the surface soils with the contents in the local background soils. The EF values of heavy metals decreased with the order of Pb, Cu, Cr, Ni and Zn. Among them, Pb reached a medium enrichment level, and its anthropogenic content was more than 50% of the total content. Based on the anthropogenic heavy metal contents, atmospheric deposition and livestock manure were identified as the two main anthropogenic heavy metal sources. The MLR-APCS simulation results showed that atmospheric deposition could contribute on average 42.41%, 37.58% and 37.26% of total Pb, Cr and Ni contents, respectively, while livestock manure contributed 41.67% of total Cu and 39.39% of total Zn contents. In general, this study provided a reliable method for quantitative identification of anthropogenic heavy metal sources in farmland soil, which can be applied in other similar areas.
2022, 40(9): 178-185,214.
doi: 10.13205/j.hjgc.202209024
Abstract:
Study of typical polycyclic aromatic hydrocarbons(PAHs) in rocky desertification soil and the physicochemical properties of rocky desertification soil effect on the migration mechanism of PAHs, typical lime soil in the different rocky desertification areas in Guizhou was carried out. Phenanthrene and pyrene were selected as the subjects, and batch desorption method combined with Pearson correlation analysis was used to study the desorption behavior of these two pollutants in different solutions. The results showed that the higher the rocky desertification grades, the easier the desorption of phenanthrene and pyrene, with the desorption hysteresis coefficient(HI) of phenanthrene and pyrene decreased from 0.73 and 0.46 for non-rocky desertification, to 0.54 and 0.28 for strong rocky desertification, respectively. The nonlinear index(N) of phenanthrene and pyrene was increased from 0.514 and 0.557 for non-rocky desertification, to 0.606 and 0.637 for strong rocky desertification, respectively. The results of desorption kinetic showed that as the rocky desertification grade increased, the fast desorption fraction(Frap) of phenanthrene and pyrene was increased and the amplification was 24.14% and 18.14%, respectively; the fast desorption rate(Krap) of phenanthrene and pyrene was increased from 6.56 and 1.26 h-1 to 8.16 and 7.98 h-1, respectively. The four primary parameters affecting the desorption of phenanthrene and pyrene in rocky desertification grades soil in Guizhou province were soil organic matter content, degree of porosity, specific surface area and cation exchange capacity, which were all negatively correlated with the desorption capacity of phenanthrene and pyrene in rocky desertification soil. The abundant calcium in rocky desertification soil was also an essential factor in the effect of phenanthrene and pyrene desorption, and in the electrolyte solution, Ca2+ enhanced the desorption of phenanthrene and pyrene compared to trials under different desorption conditions. The study found that phenanthrene and pyrene desorption were easier in soil with higher rocky desertification grade, which was closely related to the calcium-rich properties of the soil.
Study of typical polycyclic aromatic hydrocarbons(PAHs) in rocky desertification soil and the physicochemical properties of rocky desertification soil effect on the migration mechanism of PAHs, typical lime soil in the different rocky desertification areas in Guizhou was carried out. Phenanthrene and pyrene were selected as the subjects, and batch desorption method combined with Pearson correlation analysis was used to study the desorption behavior of these two pollutants in different solutions. The results showed that the higher the rocky desertification grades, the easier the desorption of phenanthrene and pyrene, with the desorption hysteresis coefficient(HI) of phenanthrene and pyrene decreased from 0.73 and 0.46 for non-rocky desertification, to 0.54 and 0.28 for strong rocky desertification, respectively. The nonlinear index(N) of phenanthrene and pyrene was increased from 0.514 and 0.557 for non-rocky desertification, to 0.606 and 0.637 for strong rocky desertification, respectively. The results of desorption kinetic showed that as the rocky desertification grade increased, the fast desorption fraction(Frap) of phenanthrene and pyrene was increased and the amplification was 24.14% and 18.14%, respectively; the fast desorption rate(Krap) of phenanthrene and pyrene was increased from 6.56 and 1.26 h-1 to 8.16 and 7.98 h-1, respectively. The four primary parameters affecting the desorption of phenanthrene and pyrene in rocky desertification grades soil in Guizhou province were soil organic matter content, degree of porosity, specific surface area and cation exchange capacity, which were all negatively correlated with the desorption capacity of phenanthrene and pyrene in rocky desertification soil. The abundant calcium in rocky desertification soil was also an essential factor in the effect of phenanthrene and pyrene desorption, and in the electrolyte solution, Ca2+ enhanced the desorption of phenanthrene and pyrene compared to trials under different desorption conditions. The study found that phenanthrene and pyrene desorption were easier in soil with higher rocky desertification grade, which was closely related to the calcium-rich properties of the soil.
2022, 40(9): 186-191.
doi: 10.13205/j.hjgc.202209025
Abstract:
Ozone deep oxidation combined with wet absorption technology has been successfully applied to many sets of ultra-low emission treatment projects for large-scale sintering flue gas, and running stably for many years. However, there is no consensus on whether the oxidation products can be efficiently transmitted from the gas phase to the liquid phase, and whether the nitrogen balance can be realized when the flue gas passing through the absorption system. Therefore, one ozone deep oxidation combined with wet absorption project for 300 m2 sintering flue gas in an iron and steel company was taken as an example, and this study established a nitrogen balance research method with clear nitrogen balance boundary, specific nitrogen input, output and accumulation items, and less dynamic parameters. Based on this method, the nitrogen balance was studied. The results showed that the nitrogen conversion rate of the system was 96.4%, which showed that NOx in flue gas could be efficiently absorbed after ozone deep oxidation. Gaseous NOx entered and discharged from the desulfurization and denitration system with flue gas, NO3- entered the desulfurization and denitration system accompanying flushing water or discharged accompanying gypsum, NO3- accumulated in the absorption tower and buffer tank were the most critical nitrogen input, output and accumulation items, which were also the main items to be considered in the actual project.
Ozone deep oxidation combined with wet absorption technology has been successfully applied to many sets of ultra-low emission treatment projects for large-scale sintering flue gas, and running stably for many years. However, there is no consensus on whether the oxidation products can be efficiently transmitted from the gas phase to the liquid phase, and whether the nitrogen balance can be realized when the flue gas passing through the absorption system. Therefore, one ozone deep oxidation combined with wet absorption project for 300 m2 sintering flue gas in an iron and steel company was taken as an example, and this study established a nitrogen balance research method with clear nitrogen balance boundary, specific nitrogen input, output and accumulation items, and less dynamic parameters. Based on this method, the nitrogen balance was studied. The results showed that the nitrogen conversion rate of the system was 96.4%, which showed that NOx in flue gas could be efficiently absorbed after ozone deep oxidation. Gaseous NOx entered and discharged from the desulfurization and denitration system with flue gas, NO3- entered the desulfurization and denitration system accompanying flushing water or discharged accompanying gypsum, NO3- accumulated in the absorption tower and buffer tank were the most critical nitrogen input, output and accumulation items, which were also the main items to be considered in the actual project.
2022, 40(9): 192-198,207.
doi: 10.13205/j.hjgc.202209026
Abstract:
In this paper, CFD Fluent was used to carry out a numerical simulation study on the tooth side shear cavitator. The changes in the cavitation between tooth vortex, the volume fraction of cavitation bubbles, and turbulent kinetic energy were analyzed. And the influence of operating parameters, such as rotation speed and processing capacity on the cavitation performance of the cavitator was obtained. The results showed that the vortex in the cavitator was the main way to generate cavitation bubbles. The vortex between the fixed teeth and the movable teeth was generated by the fluid impacting the wall surface and swirling with the injected fluid. However, the vortex between the tooth flanks was formed by the mechanical shear of the two flanks. It meant that sufficient mechanical shearing and shearing area could make the vortex distribution between tooth flanks the widest, indicating that increasing mechanical shearing could effectively induce the formation of cavitation bubbles. The collapse of cavitation bubbles caused the turbulent kinetic energy at the sharp edge of the tooth tip to increase, and the turbulent kinetic energy increased with the increase in rotational speed. It meant that the cavitator could not only increase the content of cavitation bubbles, but also increased the collapse rate of cavitation bubbles, which effectively improved the cavitation performance. However, the volume fraction of cavitation bubbles decreased with the increase of the processing volume, so as the cavitation performance.
In this paper, CFD Fluent was used to carry out a numerical simulation study on the tooth side shear cavitator. The changes in the cavitation between tooth vortex, the volume fraction of cavitation bubbles, and turbulent kinetic energy were analyzed. And the influence of operating parameters, such as rotation speed and processing capacity on the cavitation performance of the cavitator was obtained. The results showed that the vortex in the cavitator was the main way to generate cavitation bubbles. The vortex between the fixed teeth and the movable teeth was generated by the fluid impacting the wall surface and swirling with the injected fluid. However, the vortex between the tooth flanks was formed by the mechanical shear of the two flanks. It meant that sufficient mechanical shearing and shearing area could make the vortex distribution between tooth flanks the widest, indicating that increasing mechanical shearing could effectively induce the formation of cavitation bubbles. The collapse of cavitation bubbles caused the turbulent kinetic energy at the sharp edge of the tooth tip to increase, and the turbulent kinetic energy increased with the increase in rotational speed. It meant that the cavitator could not only increase the content of cavitation bubbles, but also increased the collapse rate of cavitation bubbles, which effectively improved the cavitation performance. However, the volume fraction of cavitation bubbles decreased with the increase of the processing volume, so as the cavitation performance.
2022, 40(9): 199-207.
doi: 10.13205/j.hjgc.202209027
Abstract:
With the high-quality development of urbanization, the standard of urban stormwater drainage and flooding alleviation are gradually increasing, therefore, how to realize the upgrade of stormwater drainage systems in developed areas is one of the important aspects of urban renewal. Taking a post-development area in Beijing as the research object, the pathways for upgrading the capacity of stormwater drainage system and the standard of flooding alleviation according to the revised Standard for the Design of Outdoor Wastewater Engineering(GB 50014—2021) were proposed and evaluated by SWMM. The results showed that, through the sponge city construction, the capacity of the existing stormwater drainage pipe network could be improved to 2-year return periods from 1-year, when the volume capture ratio of annual rainfall was 80%. On basis of sponge city construction, the operation of the stormwater drainage pipe was evaluated under the flooding alleviation standard of 20-year's return periods, then the centralized and decentralized distribution ways of detention tanks were further proposed and compared. The simulation results showed that the centralized distribution of detention tanks, which located nearby the outlet of the stormwater drainage pipe, couldn't alleviate the overflow from the drainage pipes in the upstream area, while the decentralized distribution of detention tanks could effectively eliminate the overflow from the drainage pipes in the upstream area, and upgrading the flooding alleviation capacity to 20-years' s return period. Therefore, according to site conditions, the optimal pathways to upgrading the capacity of stormwater drainage were sponge city construction, and upgrading the standard of flooding defense was the decentralized distribution of detention tanks in urban post-development areas.
With the high-quality development of urbanization, the standard of urban stormwater drainage and flooding alleviation are gradually increasing, therefore, how to realize the upgrade of stormwater drainage systems in developed areas is one of the important aspects of urban renewal. Taking a post-development area in Beijing as the research object, the pathways for upgrading the capacity of stormwater drainage system and the standard of flooding alleviation according to the revised Standard for the Design of Outdoor Wastewater Engineering(GB 50014—2021) were proposed and evaluated by SWMM. The results showed that, through the sponge city construction, the capacity of the existing stormwater drainage pipe network could be improved to 2-year return periods from 1-year, when the volume capture ratio of annual rainfall was 80%. On basis of sponge city construction, the operation of the stormwater drainage pipe was evaluated under the flooding alleviation standard of 20-year's return periods, then the centralized and decentralized distribution ways of detention tanks were further proposed and compared. The simulation results showed that the centralized distribution of detention tanks, which located nearby the outlet of the stormwater drainage pipe, couldn't alleviate the overflow from the drainage pipes in the upstream area, while the decentralized distribution of detention tanks could effectively eliminate the overflow from the drainage pipes in the upstream area, and upgrading the flooding alleviation capacity to 20-years' s return period. Therefore, according to site conditions, the optimal pathways to upgrading the capacity of stormwater drainage were sponge city construction, and upgrading the standard of flooding defense was the decentralized distribution of detention tanks in urban post-development areas.
2022, 40(9): 208-214.
doi: 10.13205/j.hjgc.202209028
Abstract:
In this paper, aiming at the problem of the decrease of periodic water production volume of the spherical high-speed mixed bed in the power plants, a three-dimensional model of a typical spherical high-speed mixed bed water distribution device was established, and the dome, wave baffle and self-developed spiral diversion were studied using CFD and fluid-solid coupling methods. The performance and difference of the water distribution device in terms of the distribution of condensed water, the flow characteristics, and the changes in the mechanical properties of the structure under the action of the flow load were determined. The speed standard deviation was used as the fluid flow uniformity index, and the maximum deformation of the porous plate was used as the anti-deformation index. The calculation results showed that, at a flow rate of 200~700 t/h, compared with the dome-shaped baffle and corrugated plate structure, the water distribution uniformity of the self-developed spiral deflector water distribution device was increased by 47.3%~59.3%. And then the maximum deformation decreased by 12.2%~27.2%, and the water distribution effect was improved significantly.
In this paper, aiming at the problem of the decrease of periodic water production volume of the spherical high-speed mixed bed in the power plants, a three-dimensional model of a typical spherical high-speed mixed bed water distribution device was established, and the dome, wave baffle and self-developed spiral diversion were studied using CFD and fluid-solid coupling methods. The performance and difference of the water distribution device in terms of the distribution of condensed water, the flow characteristics, and the changes in the mechanical properties of the structure under the action of the flow load were determined. The speed standard deviation was used as the fluid flow uniformity index, and the maximum deformation of the porous plate was used as the anti-deformation index. The calculation results showed that, at a flow rate of 200~700 t/h, compared with the dome-shaped baffle and corrugated plate structure, the water distribution uniformity of the self-developed spiral deflector water distribution device was increased by 47.3%~59.3%. And then the maximum deformation decreased by 12.2%~27.2%, and the water distribution effect was improved significantly.
2022, 40(9): 215-223,53.
doi: 10.13205/j.hjgc.202209029
Abstract:
Focusing on the goal of building a high-standard water system of Tianjin Eco-city, this paper analyzed the water environment problems and technical need at different stages of development, comprehensively carried out research on the planning, construction and management technology of water system and sponge city, and innovatively formed a new water system planning mode of Eco-city that coordinated all water related facilities, and a sponge city planning strategy that combined the construction of large water systems with the whole process of gray, green and blue. It developed the technology of multi-source and multi-functional purification and treatment of unconventional water, the technology of water quality maintenance and ecological restoration of landscape water, the rainwater runoff pollution control technology of biological detention facilities in saline alkali areas, the rainwater regulation and utilization technology under the influence of saline alkali, the landscape ecological improvement technology based on the improvement of saline soil and the construction of salt tolerant plant communities. And it constructed Tianjin Eco-city water system intelligent management platform, based on the water hydrodynamic-quality coupling model, multi-source water replenishment optimization scheduling model and waterlogging model. The research results had been applied to the planning, construction and management of the water system of Tianjin Eco-city and sponge city, achieving an unconventional water utilization rate of 50% above, water quality class Ⅳ of Environmental Quality Standards for Suface Water(GB 3838—2002), an annual total runoff control rate of 80% above, a runoff pollution reduction rate of 65% above(based on SS), and an annual total rainwater resource utilization of more than 300000 m3. It also optimized the structure of water resources, improved the efficiency of water resource utilization, and comprehensively improved the water environment quality of Tianjin Eco-city. The collaborative management level of dynamic linkage and joint control of water related facilities had been improved. The former saline alkali wasteland has become a prosperous and livable new city, which provided reference for the high standard construction of water systems and sponge cities in similar regions.
Focusing on the goal of building a high-standard water system of Tianjin Eco-city, this paper analyzed the water environment problems and technical need at different stages of development, comprehensively carried out research on the planning, construction and management technology of water system and sponge city, and innovatively formed a new water system planning mode of Eco-city that coordinated all water related facilities, and a sponge city planning strategy that combined the construction of large water systems with the whole process of gray, green and blue. It developed the technology of multi-source and multi-functional purification and treatment of unconventional water, the technology of water quality maintenance and ecological restoration of landscape water, the rainwater runoff pollution control technology of biological detention facilities in saline alkali areas, the rainwater regulation and utilization technology under the influence of saline alkali, the landscape ecological improvement technology based on the improvement of saline soil and the construction of salt tolerant plant communities. And it constructed Tianjin Eco-city water system intelligent management platform, based on the water hydrodynamic-quality coupling model, multi-source water replenishment optimization scheduling model and waterlogging model. The research results had been applied to the planning, construction and management of the water system of Tianjin Eco-city and sponge city, achieving an unconventional water utilization rate of 50% above, water quality class Ⅳ of Environmental Quality Standards for Suface Water(GB 3838—2002), an annual total runoff control rate of 80% above, a runoff pollution reduction rate of 65% above(based on SS), and an annual total rainwater resource utilization of more than 300000 m3. It also optimized the structure of water resources, improved the efficiency of water resource utilization, and comprehensively improved the water environment quality of Tianjin Eco-city. The collaborative management level of dynamic linkage and joint control of water related facilities had been improved. The former saline alkali wasteland has become a prosperous and livable new city, which provided reference for the high standard construction of water systems and sponge cities in similar regions.
2022, 40(9): 224-232.
doi: 10.13205/j.hjgc.202209030
Abstract:
The proposal of “zero-waste city” construction pilot symbolizes the implementation of the “zero-waste society” strategy in China. In this study, material flow analysis was used to quantify urban material metabolism in Panjin from 2005 to 2018. The comprehensive evaluation of the analytic hierarchy process and entropy weight method was adopted to evaluate the development level of the urban economy, resources, and environmental subsystems. Using system dynamics, this paper explored the potential of “zero-waste city” comprehensive management to optimize urban metabolic systems compared with other development modes. The results showed that the material input-output of Panjin had the characteristics of high input, high emission, and high hidden flow. The limited development of resource efficiency affected the overall level of urban metabolism. Under the comprehensive management mode of “zero-waste city”, it was expected to increase resource productivity by 20.29% and environmental efficiency by four times by 2025, based on 2018, greatly promoting the optimization of resources, environment, and economy of the urban metabolic system.
The proposal of “zero-waste city” construction pilot symbolizes the implementation of the “zero-waste society” strategy in China. In this study, material flow analysis was used to quantify urban material metabolism in Panjin from 2005 to 2018. The comprehensive evaluation of the analytic hierarchy process and entropy weight method was adopted to evaluate the development level of the urban economy, resources, and environmental subsystems. Using system dynamics, this paper explored the potential of “zero-waste city” comprehensive management to optimize urban metabolic systems compared with other development modes. The results showed that the material input-output of Panjin had the characteristics of high input, high emission, and high hidden flow. The limited development of resource efficiency affected the overall level of urban metabolism. Under the comprehensive management mode of “zero-waste city”, it was expected to increase resource productivity by 20.29% and environmental efficiency by four times by 2025, based on 2018, greatly promoting the optimization of resources, environment, and economy of the urban metabolic system.
2022, 40(9): 233-237.
doi: 10.13205/j.hjgc.202209031
Abstract:
Intensive integrated solid refuse disposal industrial parks are the development trend of waste disposal in China. So it is necessary to break through the technical problems of the cross-regional coordinated transfer of refuse. Compared with the traditional land transportation modes of refuse, water transportation has obvious advantages in long-distance transportation, but the related research is relatively lacking. We firstly analyze the development history of water transfer for refuse and its derived fuels. Then we compare the advantages and disadvantages of bulk refuse transportation, integrated container-vehicle transportation, container transportation, and refuse-derived fuel packaging and transportation technologies in detail. Finally, we propose optimization measures in three aspects, improvement of regulations and policies, standardization of operation methods, and upgrading of equipment for environmental protection and emergency response. This study can provide technical support for the realization of trans-regional water transfer of refuse and derived fuel.
Intensive integrated solid refuse disposal industrial parks are the development trend of waste disposal in China. So it is necessary to break through the technical problems of the cross-regional coordinated transfer of refuse. Compared with the traditional land transportation modes of refuse, water transportation has obvious advantages in long-distance transportation, but the related research is relatively lacking. We firstly analyze the development history of water transfer for refuse and its derived fuels. Then we compare the advantages and disadvantages of bulk refuse transportation, integrated container-vehicle transportation, container transportation, and refuse-derived fuel packaging and transportation technologies in detail. Finally, we propose optimization measures in three aspects, improvement of regulations and policies, standardization of operation methods, and upgrading of equipment for environmental protection and emergency response. This study can provide technical support for the realization of trans-regional water transfer of refuse and derived fuel.
2022, 40(9): 238-245,269.
doi: 10.13205/j.hjgc.202209032
Abstract:
As one of the most important components of microbial aggregates, the compositions and contents of extracellular polymeric substances(EPS) are closely related to the structure, functional activities and surface properties of microbial aggregates. Based on the existed research findings, the roles of EPS in maintaining the structural composition and strengthening the functional activities of microbial aggregates were systematically reviewed in this article. The modulating effects of EPS on the mass transfer performance, hydrophilia/hydrophobicity, physiochemical stability, rheological property and dewaterability of microbial aggregates are further summarized to explore the potential mechanisms involved in the influences of EPS on their functions. This article can provide a theoretical and scientific basis for improving the aggregation properties of microbial aggregates, the slurry separation efficiency and sewage treatment capacity.
As one of the most important components of microbial aggregates, the compositions and contents of extracellular polymeric substances(EPS) are closely related to the structure, functional activities and surface properties of microbial aggregates. Based on the existed research findings, the roles of EPS in maintaining the structural composition and strengthening the functional activities of microbial aggregates were systematically reviewed in this article. The modulating effects of EPS on the mass transfer performance, hydrophilia/hydrophobicity, physiochemical stability, rheological property and dewaterability of microbial aggregates are further summarized to explore the potential mechanisms involved in the influences of EPS on their functions. This article can provide a theoretical and scientific basis for improving the aggregation properties of microbial aggregates, the slurry separation efficiency and sewage treatment capacity.
2022, 40(9): 246-252.
doi: 10.13205/j.hjgc.202209033
Abstract:
Refractory organic contaminants in water bodies endanger the safety of the water environment and may typically be removed by oxidation. As an environmentally friendly material, cyclodextrin-mediated enhanced oxidation can extend the half-life of oxidants in water, create an oxidizing "micro-environment", increase the removal rates of organic pollutants, and broaden the application of chemical in-situ remediation, all of which have received increasing attention from environmental researchers. This review summarized the binary and ternary inclusion complex mechanisms between cyclodextrin and contaminants and analyzed the factors affecting oxidation efficiency. It further illustrated the role of inclusion in oxidant protection, bridging oxidants and pollutants, increasing oxidation efficiency, and regulating oxidation products. The efficacy of cyclodextrin-mediated enhanced oxidation in removing refractory organic contaminants in real-world applications was also examined in this review, as well as the directions and prospects of its application.
Refractory organic contaminants in water bodies endanger the safety of the water environment and may typically be removed by oxidation. As an environmentally friendly material, cyclodextrin-mediated enhanced oxidation can extend the half-life of oxidants in water, create an oxidizing "micro-environment", increase the removal rates of organic pollutants, and broaden the application of chemical in-situ remediation, all of which have received increasing attention from environmental researchers. This review summarized the binary and ternary inclusion complex mechanisms between cyclodextrin and contaminants and analyzed the factors affecting oxidation efficiency. It further illustrated the role of inclusion in oxidant protection, bridging oxidants and pollutants, increasing oxidation efficiency, and regulating oxidation products. The efficacy of cyclodextrin-mediated enhanced oxidation in removing refractory organic contaminants in real-world applications was also examined in this review, as well as the directions and prospects of its application.
2022, 40(9): 253-261.
doi: 10.13205/j.hjgc.202209034
Abstract:
The iron and steel industry is a key basic industry in China, and a typical industry with high air pollutant emissions, including huge quantities of sulfur dioxide(SO2) and nitrogen oxides(NOx). With the implementation of ultra-low emission standards in the iron and steel industry, it is urgent to renovate the existing or build new advanced desulfurization and denitration facilities in the sintering process. Based on the introduction of the characteristics of the sintering flue gas and the changes in emission standards, this paper summarizes the application status of separate desulfurization technologies, separate denitrification technologies and simultaneous desulfurization and denitration technologies, as well as the research and development progress of simultaneous desulfurization and denitration technologies, and systematically looks forward to the future development prospects of these technologies. The results indicate that among the separate desulfurization and denitrification technologies, semi-dry desulfurization and low temperature selective catalytic reduction(SCR) denitration have a high potential for application. Meanwhile, the process combination of semi-dry desulfurization+bag dust-removal+SCR has the highest cleaning efficiency. Among the simultaneous desulfurization and denitrification technologies, oxidation method and activated coke method still need further improvement in efficiency and cost, and the simultaneous desulfurization and denitrification technologies in research have a promising potential for long-term development.
The iron and steel industry is a key basic industry in China, and a typical industry with high air pollutant emissions, including huge quantities of sulfur dioxide(SO2) and nitrogen oxides(NOx). With the implementation of ultra-low emission standards in the iron and steel industry, it is urgent to renovate the existing or build new advanced desulfurization and denitration facilities in the sintering process. Based on the introduction of the characteristics of the sintering flue gas and the changes in emission standards, this paper summarizes the application status of separate desulfurization technologies, separate denitrification technologies and simultaneous desulfurization and denitration technologies, as well as the research and development progress of simultaneous desulfurization and denitration technologies, and systematically looks forward to the future development prospects of these technologies. The results indicate that among the separate desulfurization and denitrification technologies, semi-dry desulfurization and low temperature selective catalytic reduction(SCR) denitration have a high potential for application. Meanwhile, the process combination of semi-dry desulfurization+bag dust-removal+SCR has the highest cleaning efficiency. Among the simultaneous desulfurization and denitrification technologies, oxidation method and activated coke method still need further improvement in efficiency and cost, and the simultaneous desulfurization and denitrification technologies in research have a promising potential for long-term development.
2022, 40(9): 262-269.
doi: 10.13205/j.hjgc.202209035
Abstract:
In-situ remediation of soil and groundwater is mainly realized through vertical remediation wells technology, but this technology has a series of problems. The horizontal remediation wells(HRWs) technique is an innovative in-situ soil/groundwater remediation technology at contaminated sites, which can fully overcome the shortcomings of vertical wells. It can be used to target and clean up the contaminants precisely by means of horizontal directional drilling collaborated with conventional methods, such as chemical oxidation/reduction, soil vapor extraction, groundwater pump and treat, etc. It is mainly used at sites where conventional vertical drilling or trenching would be undesirable or impractical, and is especially suitable for contaminated soil and groundwater remediation beneath surface obstructions and active facilities. At present, the research and application of HRWs technology have not been conducted widely in China. The research advances of HRWs were introduced in the aspects of principles and characteristics, advantages and limitations as well as the history and development trend.This new technology was applied and tested at a petroleum hydrocarbon contaminated site in N City, J Province. The results show that the implementation of this technology is not limited by the active surface facilities with little disturbance to the surrounding environment. It has a greater contact area with contamination. The overall concentration of petroleum hydrocarbon in groundwater reached the remediation target value and was reduced by 96.47%. The successful demonstration of this technique can provide a practical reference and new vision for the development of in-situ remediation technology in China.
In-situ remediation of soil and groundwater is mainly realized through vertical remediation wells technology, but this technology has a series of problems. The horizontal remediation wells(HRWs) technique is an innovative in-situ soil/groundwater remediation technology at contaminated sites, which can fully overcome the shortcomings of vertical wells. It can be used to target and clean up the contaminants precisely by means of horizontal directional drilling collaborated with conventional methods, such as chemical oxidation/reduction, soil vapor extraction, groundwater pump and treat, etc. It is mainly used at sites where conventional vertical drilling or trenching would be undesirable or impractical, and is especially suitable for contaminated soil and groundwater remediation beneath surface obstructions and active facilities. At present, the research and application of HRWs technology have not been conducted widely in China. The research advances of HRWs were introduced in the aspects of principles and characteristics, advantages and limitations as well as the history and development trend.This new technology was applied and tested at a petroleum hydrocarbon contaminated site in N City, J Province. The results show that the implementation of this technology is not limited by the active surface facilities with little disturbance to the surrounding environment. It has a greater contact area with contamination. The overall concentration of petroleum hydrocarbon in groundwater reached the remediation target value and was reduced by 96.47%. The successful demonstration of this technique can provide a practical reference and new vision for the development of in-situ remediation technology in China.
