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2022 Vol. 40, No. 1
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2022, 40(1): 1-7,206.
doi: 10.13205/j.hjgc.202201001
Abstract:
Over the past 40 years of reform and opening-up, China's industrial development has improved rapidly and built the most complete industrial system in the world. However, China has also suffered from the negative impact of extensive development, especially the environmental pollution caused by the heavy and chemical industry. In this paper, the China's domestic and international concepts, strategies, policies and evaluation methods of industrial pollution control were compared on the basis of advanced theories and new industrial pollution control technologies. The innovation and beneficial practices in different control stages were summarized systematically. Furthermore, the development tendency of industrial pollution control in the future was put forward. The results could provide practical and effective theories and methods for scientific research personnel and enterprise technicians committed to industrial pollution control.
Over the past 40 years of reform and opening-up, China's industrial development has improved rapidly and built the most complete industrial system in the world. However, China has also suffered from the negative impact of extensive development, especially the environmental pollution caused by the heavy and chemical industry. In this paper, the China's domestic and international concepts, strategies, policies and evaluation methods of industrial pollution control were compared on the basis of advanced theories and new industrial pollution control technologies. The innovation and beneficial practices in different control stages were summarized systematically. Furthermore, the development tendency of industrial pollution control in the future was put forward. The results could provide practical and effective theories and methods for scientific research personnel and enterprise technicians committed to industrial pollution control.
2022, 40(1): 8-12,20.
doi: 10.13205/j.hjgc.202201002
Abstract:
In recent years, in view of the fact that the flow along the ditch is non-uniform flow for linear drainage pipe of stormwater runoff, application of Chézy's formula will bring large errors when applied to engineering design. The experimental physical model method was adopt to investigate the effect of the inflow along the way on the constant flow surface curve of the open channel. Meanwhile, the water level was measured by the piezometer, the effect of water surface curve under the conditions of different slopes, width of ditch bottom and wall surface roughness was investigated, and compared with the calculation results by Chézy's formula. The results showed that the water surface curve in the ditch increased along the way when there was inflow along the flow way under different experimental conditions, which was obviously different from the calculation results by Chézy's formula, and the calculation relationship between flow rate and water depth was further fitted. These results will significantly contribute to optimize the design and calculation of the hydraulic cross-section of the even inflow ditches along the road such as side ditches and linear drainage system.
In recent years, in view of the fact that the flow along the ditch is non-uniform flow for linear drainage pipe of stormwater runoff, application of Chézy's formula will bring large errors when applied to engineering design. The experimental physical model method was adopt to investigate the effect of the inflow along the way on the constant flow surface curve of the open channel. Meanwhile, the water level was measured by the piezometer, the effect of water surface curve under the conditions of different slopes, width of ditch bottom and wall surface roughness was investigated, and compared with the calculation results by Chézy's formula. The results showed that the water surface curve in the ditch increased along the way when there was inflow along the flow way under different experimental conditions, which was obviously different from the calculation results by Chézy's formula, and the calculation relationship between flow rate and water depth was further fitted. These results will significantly contribute to optimize the design and calculation of the hydraulic cross-section of the even inflow ditches along the road such as side ditches and linear drainage system.
2022, 40(1): 13-20.
doi: 10.13205/j.hjgc.202201003
Abstract:
To understand the treatment effect of total nitrogen in low-polluted wastewater by composite constructed wetland system and the characteristics of microbial community structure in the constructed wetland consisted of surface flow-subsurface flow-submerged plant pond, we researched the removal rates of TN, NH4+-N, NO3--N and NO2--N in the wastewater by the system. High throughput sequencing method was applied to reveal the microbial community structure and diversity in the units at all levels. The results showed that the effluent of the composite constructed wetland system reached the class Ⅳ of Environmental Quality Standard for Surface Water under the hydraulic load of 0.12~0.24 m3/(m2 · d), and had a good removal effect on pollutants. And the removal rate of TN, NH4+-N was 62.35%~76.86% and 36.94%~74.68%. The main denitrification microorganisms in each unit showed great differences. At the genus level, the main denitrification microorganisms in the surface flow wetland were Nitrospira, 996-1 and Hyphomicrobium. The main denitrification bacteria groups in the subsurface flow wetland were Cupriavidus and Acinetobacter. The main denitrification microorganisms in the submerged plant pond were Methylotenera and Methylophilus. The results indicated that all the units contributed to the removal of total nitrogen but there were differences between them.
To understand the treatment effect of total nitrogen in low-polluted wastewater by composite constructed wetland system and the characteristics of microbial community structure in the constructed wetland consisted of surface flow-subsurface flow-submerged plant pond, we researched the removal rates of TN, NH4+-N, NO3--N and NO2--N in the wastewater by the system. High throughput sequencing method was applied to reveal the microbial community structure and diversity in the units at all levels. The results showed that the effluent of the composite constructed wetland system reached the class Ⅳ of Environmental Quality Standard for Surface Water under the hydraulic load of 0.12~0.24 m3/(m2 · d), and had a good removal effect on pollutants. And the removal rate of TN, NH4+-N was 62.35%~76.86% and 36.94%~74.68%. The main denitrification microorganisms in each unit showed great differences. At the genus level, the main denitrification microorganisms in the surface flow wetland were Nitrospira, 996-1 and Hyphomicrobium. The main denitrification bacteria groups in the subsurface flow wetland were Cupriavidus and Acinetobacter. The main denitrification microorganisms in the submerged plant pond were Methylotenera and Methylophilus. The results indicated that all the units contributed to the removal of total nitrogen but there were differences between them.
2022, 40(1): 21-26,223.
doi: 10.13205/j.hjgc.202201004
Abstract:
To reveal the effect of carbon resource addition strategies on nitrogen and phosphorus removal in low carbon wastewater, an A2/O system was employed to treat the simulated low C/N wastewater(C/N 2.0~4.0) with carbon resource addition respectively at the sludge return tank and the water inlet. The nitrogen and phosphorus removal efficiency and microbial community structure were comparatively investigated under different conditions.Resultsshowed that higher removal efficiency of nitrogen and phosphorus was easily achieved by adding the same amount of carbon source to the sludge return tank(stage Ⅲ), compared with the traditional way of adding carbon source at the water inlet(stage Ⅳ). When the A2/O system was stably operated at stage Ⅲ, the removal rate of TN and TP was 54.5% and 63.9% respectively, higher than that at stage Ⅳ(the removal rate of TN and TP was 44.9% and 21.7%, respectively). High-throughout sequencing results indicated that the microbial abundance and diversity changed with carbon resource addition strategies. Meanwhile, the way of adding carbon source to the sludge return tank was conducive to the enrichment of dominant flora. Rhodoplanes(2.3%), Dechloromonas(1.6%) and Hyphomicrobium(1.4%) was the dominant genus at stage Ⅲ, and the proportions of the above three genus were also higher than that in stage Ⅳ when the carbon resource was added to the inlet.
To reveal the effect of carbon resource addition strategies on nitrogen and phosphorus removal in low carbon wastewater, an A2/O system was employed to treat the simulated low C/N wastewater(C/N 2.0~4.0) with carbon resource addition respectively at the sludge return tank and the water inlet. The nitrogen and phosphorus removal efficiency and microbial community structure were comparatively investigated under different conditions.Resultsshowed that higher removal efficiency of nitrogen and phosphorus was easily achieved by adding the same amount of carbon source to the sludge return tank(stage Ⅲ), compared with the traditional way of adding carbon source at the water inlet(stage Ⅳ). When the A2/O system was stably operated at stage Ⅲ, the removal rate of TN and TP was 54.5% and 63.9% respectively, higher than that at stage Ⅳ(the removal rate of TN and TP was 44.9% and 21.7%, respectively). High-throughout sequencing results indicated that the microbial abundance and diversity changed with carbon resource addition strategies. Meanwhile, the way of adding carbon source to the sludge return tank was conducive to the enrichment of dominant flora. Rhodoplanes(2.3%), Dechloromonas(1.6%) and Hyphomicrobium(1.4%) was the dominant genus at stage Ⅲ, and the proportions of the above three genus were also higher than that in stage Ⅳ when the carbon resource was added to the inlet.
2022, 40(1): 27-31,51.
doi: 10.13205/j.hjgc.202201005
Abstract:
To explore the permeability of the bioretention cell during sewage treatment under continuous operation, the system performance was investigated by monitoring the changes of the permeability coefficient and porosity under different hydraulic load conditions. The results showed that under the same hydraulic load, the standard permeability coefficient, K20 showed a trend of first decreasing, then increasing, and finally reaching a stable stage(on about the 15 th day). The greater the hydraulic load, the greater its impact on the relative permeability coefficient. The relationship between two parameters reached a significant negative correlation level(P<0.01). Under the condition of low hydraulic load [less than 1.0 m3/(m2·d)], the permeability coefficient was positively correlated with porosity. Under the condition of higher hydraulic load [more than 2.0 m3/(m2·d)], the permeability coefficient and porosity had no significant correlation. The hydraulic load of the BRC should be controlled lower than 2.0 m3/(m2·d), when the sewage was processed under continuous operation, and the system performance was best when the hydraulic load was 1.0 m3/(m2·d). This study could provide theoretical guidance for effectively preventing BRC clogging.
To explore the permeability of the bioretention cell during sewage treatment under continuous operation, the system performance was investigated by monitoring the changes of the permeability coefficient and porosity under different hydraulic load conditions. The results showed that under the same hydraulic load, the standard permeability coefficient, K20 showed a trend of first decreasing, then increasing, and finally reaching a stable stage(on about the 15 th day). The greater the hydraulic load, the greater its impact on the relative permeability coefficient. The relationship between two parameters reached a significant negative correlation level(P<0.01). Under the condition of low hydraulic load [less than 1.0 m3/(m2·d)], the permeability coefficient was positively correlated with porosity. Under the condition of higher hydraulic load [more than 2.0 m3/(m2·d)], the permeability coefficient and porosity had no significant correlation. The hydraulic load of the BRC should be controlled lower than 2.0 m3/(m2·d), when the sewage was processed under continuous operation, and the system performance was best when the hydraulic load was 1.0 m3/(m2·d). This study could provide theoretical guidance for effectively preventing BRC clogging.
2022, 40(1): 32-37.
doi: 10.13205/j.hjgc.202201006
Abstract:
Cyanobacteria releases biotoxic microcystin(MC-LR) into the water column during its growth and reproduction, which is a potential threat to human health. Fulvic acid(FA) is a widely present aqueous environmental medium in water bodies, and the mechanism of its different molecular weight components on the photodegradation of MC-LR is unknown. In this study, we investigated the effects of molecular weight of FA and related condition factors on UV degradation of MC-LR through UV illumination experiments. The results showed that the degradation rate of MC-LR decreased and then increased with the increase of pH value; the degradation rate of MC-LR was 60.10% after 120 min of UV degradation in pure water; after FA was added, the degradation rate of MC-LR increased with the increase of its concentration, and 62.18% of MC-LR was degraded at 10 mgC/L. Under different molecular weight FA, the degradation rate range of MC-LR was 54.52%~65.61%, and the degradation process was in good accordance with the first-order reaction kinetic equation.The apparent rate constant was the highest when the molecular weight was 3~5 kDa and the concentration was 10 mgC/L, which was 0.03303 min-1. This study provided a reference for optimizing the conditional ratio between FA and MC-LR and promoting the degradation of MC-LR.
Cyanobacteria releases biotoxic microcystin(MC-LR) into the water column during its growth and reproduction, which is a potential threat to human health. Fulvic acid(FA) is a widely present aqueous environmental medium in water bodies, and the mechanism of its different molecular weight components on the photodegradation of MC-LR is unknown. In this study, we investigated the effects of molecular weight of FA and related condition factors on UV degradation of MC-LR through UV illumination experiments. The results showed that the degradation rate of MC-LR decreased and then increased with the increase of pH value; the degradation rate of MC-LR was 60.10% after 120 min of UV degradation in pure water; after FA was added, the degradation rate of MC-LR increased with the increase of its concentration, and 62.18% of MC-LR was degraded at 10 mgC/L. Under different molecular weight FA, the degradation rate range of MC-LR was 54.52%~65.61%, and the degradation process was in good accordance with the first-order reaction kinetic equation.The apparent rate constant was the highest when the molecular weight was 3~5 kDa and the concentration was 10 mgC/L, which was 0.03303 min-1. This study provided a reference for optimizing the conditional ratio between FA and MC-LR and promoting the degradation of MC-LR.
2022, 40(1): 38-45.
doi: 10.13205/j.hjgc.202201007
Abstract:
The characteristics of the rainfall runoff pollution and the first flush effect of pollutants on the underlying surfaces of typical roofing materials(asphalt, plastic steel and cement tile) in the residential areas of Tianjin were investigated, and the distribution of particles and the occurrence forms of main pollutants in rainfall runoff from roofs of different materials were also analyzed. The results of the event mean concentration(EMC) analysis showed that SS and COD were the main pollutants in rainfall runoff. The order of pollution degree of rainfall runoff was asphalt roof > cement tile roof > plastic steel roof. The main carriers of pollutants in rainfall runoff were particulate matters, which were closely related with COD and TP. The first flush phenomenon was found in different roof runoffs, among them the plastic steel roof showed higher correlation with the Sartor-Boyd model. The particle size distribution of particulate pollutants in the runoffs were mainly influenced by the rainfall and rainfall intensity. The main particulate pollutants were distributed in particles diameter range of 10~100 μm, accounting for 60%~75% of the total volume. 86%~92% of COD and 90%~95% of TP were mainly existed in the granular form, while 50%~65% of nitrogen was mainly existed in the dissolved form in rainfall runoff from different roofs.
The characteristics of the rainfall runoff pollution and the first flush effect of pollutants on the underlying surfaces of typical roofing materials(asphalt, plastic steel and cement tile) in the residential areas of Tianjin were investigated, and the distribution of particles and the occurrence forms of main pollutants in rainfall runoff from roofs of different materials were also analyzed. The results of the event mean concentration(EMC) analysis showed that SS and COD were the main pollutants in rainfall runoff. The order of pollution degree of rainfall runoff was asphalt roof > cement tile roof > plastic steel roof. The main carriers of pollutants in rainfall runoff were particulate matters, which were closely related with COD and TP. The first flush phenomenon was found in different roof runoffs, among them the plastic steel roof showed higher correlation with the Sartor-Boyd model. The particle size distribution of particulate pollutants in the runoffs were mainly influenced by the rainfall and rainfall intensity. The main particulate pollutants were distributed in particles diameter range of 10~100 μm, accounting for 60%~75% of the total volume. 86%~92% of COD and 90%~95% of TP were mainly existed in the granular form, while 50%~65% of nitrogen was mainly existed in the dissolved form in rainfall runoff from different roofs.
2022, 40(1): 46-51.
doi: 10.13205/j.hjgc.202201008
Abstract:
Waste emulsion is a kind of high-concentration organic wastewater produced from mechanical processing, which belongs to hazardous waste. Electrochemical oxidation of BDD electrode is an effective method to treat waste emulsion. In this paper, the degradation effect of the waste emulsion treated by electrochemical oxidation of the BDD electrode was studied experimentally, and the effects of current density, electrolyte type and concentration, initial pH value and reaction temperature on the degradation efficiency were investigated. The results showed that the electrochemical oxidation of BDD electrode could effectively degrade the organic matter in the waste emulsion. When Na2S2O8 was used as the electrolyte and the current density was greater than 60 mA/cm2, the COD degradation rate reached more than 99% after 4 hours of reaction, and the maximum energy consumption is about 25 kW·h/kg for per 1 kg of COD. When the current density increased from 20 mA/cm2 to 60 mA/cm2, the COD degradation rate increased by about 13 percentage points, and the energy consumption increased accordingly. When the current density was 60 mA/cm2 and the reaction time was 2 hours, the degradation efficiency of COD using Na2S2O8 as the supporting electrolyte was about 10% higher than that with NaCl and Na2SO4 as the electrolyte. Increasing electrolyte concentration, reaction temperature and acidic conditions was conducive to the degradation of organic matter. The kinetic analysis showed that the process of electrochemical oxidation of waste emulsion with BDD electrode conformed to the first-order reaction kinetic equation, and the relationship between the first-order reaction kinetic constant k and the current density kept basically linear when the current density was lower than 60 mA/cm2.
Waste emulsion is a kind of high-concentration organic wastewater produced from mechanical processing, which belongs to hazardous waste. Electrochemical oxidation of BDD electrode is an effective method to treat waste emulsion. In this paper, the degradation effect of the waste emulsion treated by electrochemical oxidation of the BDD electrode was studied experimentally, and the effects of current density, electrolyte type and concentration, initial pH value and reaction temperature on the degradation efficiency were investigated. The results showed that the electrochemical oxidation of BDD electrode could effectively degrade the organic matter in the waste emulsion. When Na2S2O8 was used as the electrolyte and the current density was greater than 60 mA/cm2, the COD degradation rate reached more than 99% after 4 hours of reaction, and the maximum energy consumption is about 25 kW·h/kg for per 1 kg of COD. When the current density increased from 20 mA/cm2 to 60 mA/cm2, the COD degradation rate increased by about 13 percentage points, and the energy consumption increased accordingly. When the current density was 60 mA/cm2 and the reaction time was 2 hours, the degradation efficiency of COD using Na2S2O8 as the supporting electrolyte was about 10% higher than that with NaCl and Na2SO4 as the electrolyte. Increasing electrolyte concentration, reaction temperature and acidic conditions was conducive to the degradation of organic matter. The kinetic analysis showed that the process of electrochemical oxidation of waste emulsion with BDD electrode conformed to the first-order reaction kinetic equation, and the relationship between the first-order reaction kinetic constant k and the current density kept basically linear when the current density was lower than 60 mA/cm2.
2022, 40(1): 52-59,77.
doi: 10.13205/j.hjgc.202201009
Abstract:
Jinghu Lake is the largest landscape lake in Sino-Singapore Tianjin eco city. It connects Gudao River and Huifeng River to form a unique water ecosystem, which is the representative of large-scale landscape water system in northern cities. Thus, the water system environment attracted great attention. Based on the investigation and analysis of the construction of water circulation purification facilities and the implementation of water quality improvement projects in Jing water system, Delft3D FM model was built to study the hydrodynamic and water quality evolution process in Jing water system under different engineering schemes, whose results were further evaluated to verify the engineering effect on water quality improving. The results indicated that the water quality of Jing water system was obviously affected by rainfall. By comparing the changes of water quality before and after the flood season, the concentration of COD and TP increased by 10% after the flood season, even increased by 60% in some river sections, but the NH3-N decrease by 20%~30% after the flood season. Furthermore, through the engineering measures, such as setting up water replenishment, removing isolation dam, and installing circulating pump & drainage pump, the hydrodynamic condition of Jing water system was greatly improved, and NH3-N and TP generally met the requirements of class IV water standard, for that NH3-N was reduced by 3%~25%, and TP was reduced by 6%~50%. Engineering measures should take water environment background, pollution source control, water conservancy facilities operation and other factors into account, to develop water quality improvement strategy.
Jinghu Lake is the largest landscape lake in Sino-Singapore Tianjin eco city. It connects Gudao River and Huifeng River to form a unique water ecosystem, which is the representative of large-scale landscape water system in northern cities. Thus, the water system environment attracted great attention. Based on the investigation and analysis of the construction of water circulation purification facilities and the implementation of water quality improvement projects in Jing water system, Delft3D FM model was built to study the hydrodynamic and water quality evolution process in Jing water system under different engineering schemes, whose results were further evaluated to verify the engineering effect on water quality improving. The results indicated that the water quality of Jing water system was obviously affected by rainfall. By comparing the changes of water quality before and after the flood season, the concentration of COD and TP increased by 10% after the flood season, even increased by 60% in some river sections, but the NH3-N decrease by 20%~30% after the flood season. Furthermore, through the engineering measures, such as setting up water replenishment, removing isolation dam, and installing circulating pump & drainage pump, the hydrodynamic condition of Jing water system was greatly improved, and NH3-N and TP generally met the requirements of class IV water standard, for that NH3-N was reduced by 3%~25%, and TP was reduced by 6%~50%. Engineering measures should take water environment background, pollution source control, water conservancy facilities operation and other factors into account, to develop water quality improvement strategy.
2022, 40(1): 60-68.
doi: 10.13205/j.hjgc.202201010
Abstract:
In this paper, Ce-MnOx was prepared for selective catalytic oxidation(SCO) of ammonia by hydrothermal and impregnation method respectively. The results demonstrated that Ce-MnOx catalysts exhibited the best NH3 oxidation activity which composited by hydrothermal method. Among them, Ce(5)-MnOx(HY) reached 98% of NH3 conversion rate and 91% of N2 selectivity, at reaction temperature of 200 ℃. The properties of the Ce-MnOx catalysts were analyzed by XRD, BET, Raman, XPS, SEM, and H2-TPR. Hydrothermally prepared Ce-MnOx possessed larger surface area(94.37 m2/g). At the same time, the distinguished catalytic activity of Ce-MnOx was attributed to abundant Mn4+ and Ce3+, high adsorbed oxygen concentration on the surface, a large number of active sites, and interaction between Mn and Ce. The results of in-situ DRIFTS showed that the —NH2 and —NH intermediates could be generated by adsorbed NH3 dehydrogenation. Consequently, —NH and atomic oxygen combined to form —HNO, which could be quickly oxidized to NO by O2. Finally, N2 and H2O were formed during the following reaction of NO with —NH2. This dissertation has significant reference value for the study of manganese-based catalysts in low-temperature ammonia oxidation and selectivity.
In this paper, Ce-MnOx was prepared for selective catalytic oxidation(SCO) of ammonia by hydrothermal and impregnation method respectively. The results demonstrated that Ce-MnOx catalysts exhibited the best NH3 oxidation activity which composited by hydrothermal method. Among them, Ce(5)-MnOx(HY) reached 98% of NH3 conversion rate and 91% of N2 selectivity, at reaction temperature of 200 ℃. The properties of the Ce-MnOx catalysts were analyzed by XRD, BET, Raman, XPS, SEM, and H2-TPR. Hydrothermally prepared Ce-MnOx possessed larger surface area(94.37 m2/g). At the same time, the distinguished catalytic activity of Ce-MnOx was attributed to abundant Mn4+ and Ce3+, high adsorbed oxygen concentration on the surface, a large number of active sites, and interaction between Mn and Ce. The results of in-situ DRIFTS showed that the —NH2 and —NH intermediates could be generated by adsorbed NH3 dehydrogenation. Consequently, —NH and atomic oxygen combined to form —HNO, which could be quickly oxidized to NO by O2. Finally, N2 and H2O were formed during the following reaction of NO with —NH2. This dissertation has significant reference value for the study of manganese-based catalysts in low-temperature ammonia oxidation and selectivity.
2022, 40(1): 69-77.
doi: 10.13205/j.hjgc.202201011
Abstract:
To understand the change of microbial community structure in the process of aerobic composting fermentation and study the biological index of ripening degree, in the trial we took cow dung as the samples, and by high-throughput sequencing, the correlation between the dynamic change of microbial community structure and environmental factors and maturity at different stages and in high and low profiles was analyzed. The results showed that the temperature, C/N and seed germination index condition was better in the upper layer than the lower layer. For the whole composting period, the bacterial abundance and diversity showed a trend of first increasing and then decreasing; the bacterial community structure was at the phylum level that Firmicutes dominated the entire composting process; at the genus level, in the heating period the dominant species was unidentified_Rhizobiaceae, in high temperature period the dominant species was Bacillus, in cooling period the dominant species wsa Nocardiopsis; Spearman correlation analysis showed that there was a very significant positive correlation(P<0.01) between Bacillus and organic matters, C/N, water content and temperature; canonical correlation analysis showed that Nocardiopsis could be used as an indicator microorganism, and OM was the prominent influencing factor; the analysis of the fitted regression equation showed that there was a strong correlation between the Chao1 index and the maturity index(R2=0.986).
To understand the change of microbial community structure in the process of aerobic composting fermentation and study the biological index of ripening degree, in the trial we took cow dung as the samples, and by high-throughput sequencing, the correlation between the dynamic change of microbial community structure and environmental factors and maturity at different stages and in high and low profiles was analyzed. The results showed that the temperature, C/N and seed germination index condition was better in the upper layer than the lower layer. For the whole composting period, the bacterial abundance and diversity showed a trend of first increasing and then decreasing; the bacterial community structure was at the phylum level that Firmicutes dominated the entire composting process; at the genus level, in the heating period the dominant species was unidentified_Rhizobiaceae, in high temperature period the dominant species was Bacillus, in cooling period the dominant species wsa Nocardiopsis; Spearman correlation analysis showed that there was a very significant positive correlation(P<0.01) between Bacillus and organic matters, C/N, water content and temperature; canonical correlation analysis showed that Nocardiopsis could be used as an indicator microorganism, and OM was the prominent influencing factor; the analysis of the fitted regression equation showed that there was a strong correlation between the Chao1 index and the maturity index(R2=0.986).
2022, 40(1): 78-85.
doi: 10.13205/j.hjgc.202201012
Abstract:
With the rapid development of China's industries and urbanization, the massive use of fossil energy has led to an increasing amount of PAHs residues in the environment, which poses serious hazards to the environment and human health. The effects of thermal desorption temperature, time and the structure of PAHs themselves on the thermal desorption were investigated with 2~4 ring PAHs. Additionally, the effect of thermal desorption on soil properties were briefly analyzed, and the energy consumption of thermal desorption in a tube furnace was also evaluated. The results showed that the desorption removal efficiency of low ring PAHs showed an increasing trend with the increase of desorption temperature and desorption time. Under the conditions of 300 ℃ and 30 min of desorption, 2 ring-PAHs was completely removed, and the removal efficiency of 3 ring-PAHs and 4 ring-PAHs was 93.22% and 83.85%, respectively. The preferred conditions for each PAHs component to meet the objective values of the remediation standard(DB11/T 811—2011) were as follows: Nap was remediated at a desorption temperature of 100 ℃ for 10 min; Phe and Ant were remediated at 250 ℃ for 30 min and 150 ℃ for 60 min, respectively; the residues of Fla and Pyr were basically higher than the standard screening values, which required further adjustment of the thermal desorption working parameters or the addition of modifiers for synergistic remediation to reduce the cost. Moreover, the proportion of coarse soil particles decreased after thermal desorption, which was consistent with the fragmentation of large particles into small particles in SEM. The results can provide theoretical references for application of thermal desorption technology in remediation of PAHs contaminated soil.
With the rapid development of China's industries and urbanization, the massive use of fossil energy has led to an increasing amount of PAHs residues in the environment, which poses serious hazards to the environment and human health. The effects of thermal desorption temperature, time and the structure of PAHs themselves on the thermal desorption were investigated with 2~4 ring PAHs. Additionally, the effect of thermal desorption on soil properties were briefly analyzed, and the energy consumption of thermal desorption in a tube furnace was also evaluated. The results showed that the desorption removal efficiency of low ring PAHs showed an increasing trend with the increase of desorption temperature and desorption time. Under the conditions of 300 ℃ and 30 min of desorption, 2 ring-PAHs was completely removed, and the removal efficiency of 3 ring-PAHs and 4 ring-PAHs was 93.22% and 83.85%, respectively. The preferred conditions for each PAHs component to meet the objective values of the remediation standard(DB11/T 811—2011) were as follows: Nap was remediated at a desorption temperature of 100 ℃ for 10 min; Phe and Ant were remediated at 250 ℃ for 30 min and 150 ℃ for 60 min, respectively; the residues of Fla and Pyr were basically higher than the standard screening values, which required further adjustment of the thermal desorption working parameters or the addition of modifiers for synergistic remediation to reduce the cost. Moreover, the proportion of coarse soil particles decreased after thermal desorption, which was consistent with the fragmentation of large particles into small particles in SEM. The results can provide theoretical references for application of thermal desorption technology in remediation of PAHs contaminated soil.
2022, 40(1): 86-93.
doi: 10.13205/j.hjgc.202201013
Abstract:
Leaching technology is one of the mainstream technologies for remediation of soil heavy metal(metal-like) pollution, but the risk of secondary contamination in leaching waste liquid is the main factor restricting its application. This study explored the best adsorption conditions and removal effect of As(Ⅲ) in soil leaching wastewater through solvent deposition of magnetic coconut shell(MCS) prepared by the modified materials. XPS, SEM analysis results showed that magnetic materials could be successfully loaded on the coconut. EDS, FT-IR analysis showed that the As(Ⅲ) could be effectively adsorbed by MCS material. We used the pseudo-second-order kinetic model and Freundlich model to simulate the MCS for the As(Ⅲ) adsorption process, and found that the adsorption process was multilayer adsorption behavior and dominated by chemical adsorption, and the complexation of hydroxyl, carboxyl and iron-containing groups on As(Ⅲ) was the main mechanisms of the adsorption. The removal efficiency of As(Ⅲ) in actual leaching waste water could reach 96.58% under the condition of MCS dosage of 20 g/L, pH of 9 and adsorption time of 120 min. The final content of As(Ⅲ) in the leaching waste water treated by MCS was lower than the discharge limit specified in the Integrated Waste Water Discharge Standard, GB 8978—1996(As≤0.5 mg/L). In conclusion, MCS is an effective adsorption material for the treatment of As(Ⅲ) contaminated soil leaching liquid.
Leaching technology is one of the mainstream technologies for remediation of soil heavy metal(metal-like) pollution, but the risk of secondary contamination in leaching waste liquid is the main factor restricting its application. This study explored the best adsorption conditions and removal effect of As(Ⅲ) in soil leaching wastewater through solvent deposition of magnetic coconut shell(MCS) prepared by the modified materials. XPS, SEM analysis results showed that magnetic materials could be successfully loaded on the coconut. EDS, FT-IR analysis showed that the As(Ⅲ) could be effectively adsorbed by MCS material. We used the pseudo-second-order kinetic model and Freundlich model to simulate the MCS for the As(Ⅲ) adsorption process, and found that the adsorption process was multilayer adsorption behavior and dominated by chemical adsorption, and the complexation of hydroxyl, carboxyl and iron-containing groups on As(Ⅲ) was the main mechanisms of the adsorption. The removal efficiency of As(Ⅲ) in actual leaching waste water could reach 96.58% under the condition of MCS dosage of 20 g/L, pH of 9 and adsorption time of 120 min. The final content of As(Ⅲ) in the leaching waste water treated by MCS was lower than the discharge limit specified in the Integrated Waste Water Discharge Standard, GB 8978—1996(As≤0.5 mg/L). In conclusion, MCS is an effective adsorption material for the treatment of As(Ⅲ) contaminated soil leaching liquid.
2022, 40(1): 94-101,116.
doi: 10.13205/j.hjgc.202201014
Abstract:
In this study, Pb-, Zn-, and Cd-contaminated soil was stabilized by chitosan-modified zeolite. Scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and toxicity characteristic leaching procedure extraction methods were used to analyze the composition of the modified materials and their stabilizing effect on multi-metal-contaminated soil. In addition, the effect of the modified material dosages, soil water content, and pH on the stabilization of the contaminated soil were investigated.Resultsshowed that the surface of the modified material had a clear fibrous structure and a uniform synaptic structure. The characteristic peak of N1 s was increased at a binding energy of approximately 400 eV, confirming that chitosan was loaded onto the surface of the zeolite and calcium silicate particles had a modifying effect. The stabilization effect reached its maximum when the maximum dosage was 10%. With the increase in water content, the leaching concentration increased slightly. Under different water content, the competition on Pb stabilization of Zn and Cd was not evident. When the soil environment was weakly acid-base or neutral, Zn and Cd showed no competitive advantage in Pb stabilization, but Zn and Cd had a stronger competitive advantage under strong acid or strong alkali environment, thereby inhibiting the stabilization of Pb. This study developed a novel and efficient soil stabilization material, providing a basis for the remediation of polymetallic contaminated sites.
In this study, Pb-, Zn-, and Cd-contaminated soil was stabilized by chitosan-modified zeolite. Scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and toxicity characteristic leaching procedure extraction methods were used to analyze the composition of the modified materials and their stabilizing effect on multi-metal-contaminated soil. In addition, the effect of the modified material dosages, soil water content, and pH on the stabilization of the contaminated soil were investigated.Resultsshowed that the surface of the modified material had a clear fibrous structure and a uniform synaptic structure. The characteristic peak of N1 s was increased at a binding energy of approximately 400 eV, confirming that chitosan was loaded onto the surface of the zeolite and calcium silicate particles had a modifying effect. The stabilization effect reached its maximum when the maximum dosage was 10%. With the increase in water content, the leaching concentration increased slightly. Under different water content, the competition on Pb stabilization of Zn and Cd was not evident. When the soil environment was weakly acid-base or neutral, Zn and Cd showed no competitive advantage in Pb stabilization, but Zn and Cd had a stronger competitive advantage under strong acid or strong alkali environment, thereby inhibiting the stabilization of Pb. This study developed a novel and efficient soil stabilization material, providing a basis for the remediation of polymetallic contaminated sites.
2022, 40(1): 102-109.
doi: 10.13205/j.hjgc.202201015
Abstract:
BTEX(benzene, toluene, ethylbenzene, xylenes, etc) are volatile organic compounds which have great impact on air quality and human health. To study pollution characteristics of BTEX in Changsha, ambient samples were collected and analyzed consecutively at two typical urban sites(site S and W) during August 2017. The results showed that the averaged concentrations of BTEX were(9.84±5.44) μg/m3 at site S and(6.35±4.68) μg/m3 at site W, respectively; and m, p-xylenes were the most abundant species among BTEX with contributions of 32.3% and 26.7%, respectively, followed by toluene with contributions of 20.6% and 22.8%, respectively. Diurnal variations of major BTEX species showed a “U” pattern with lower concentrations during 13:00—14:00 and higher concentrations during 7:00—8:00 and 16:00—17:00, which might be influenced by variation of photo-chemistry reactivity and source emission. The correlations among BTEX and relative proportions of benzene, toluene and ethylbenzene suggested that traffic-relate sources, industrial sources and solvent emissions were the major sources of ambient BTEX in Changsha. The non-carcinogenic hazard quotients of BTEX(2.89×10-4~9.35×10-2) were all lower than 1, indicating no obvious adverse carcinogenic hazard risk on the exposed population. However, the carcinogenic hazard risk values of benzene(6.41×10-6and 5.34×10-6) were higher, implying the potential cancer risks due to ambient benzene exposure in the study region.
BTEX(benzene, toluene, ethylbenzene, xylenes, etc) are volatile organic compounds which have great impact on air quality and human health. To study pollution characteristics of BTEX in Changsha, ambient samples were collected and analyzed consecutively at two typical urban sites(site S and W) during August 2017. The results showed that the averaged concentrations of BTEX were(9.84±5.44) μg/m3 at site S and(6.35±4.68) μg/m3 at site W, respectively; and m, p-xylenes were the most abundant species among BTEX with contributions of 32.3% and 26.7%, respectively, followed by toluene with contributions of 20.6% and 22.8%, respectively. Diurnal variations of major BTEX species showed a “U” pattern with lower concentrations during 13:00—14:00 and higher concentrations during 7:00—8:00 and 16:00—17:00, which might be influenced by variation of photo-chemistry reactivity and source emission. The correlations among BTEX and relative proportions of benzene, toluene and ethylbenzene suggested that traffic-relate sources, industrial sources and solvent emissions were the major sources of ambient BTEX in Changsha. The non-carcinogenic hazard quotients of BTEX(2.89×10-4~9.35×10-2) were all lower than 1, indicating no obvious adverse carcinogenic hazard risk on the exposed population. However, the carcinogenic hazard risk values of benzene(6.41×10-6and 5.34×10-6) were higher, implying the potential cancer risks due to ambient benzene exposure in the study region.
2022, 40(1): 110-116.
doi: 10.13205/j.hjgc.202201016
Abstract:
In order to find out the risk distribution of nitrogen, phosphorus and heavy metals in the surface sediments of the heavily polluted tributaries in Shahe basin, a tributary of Dongjiang River, different risk assessment methods were used. The comprehensive pollution index analysis showed that TN risk levels of heavy pollution, moderate pollution, light pollution and clean accounted for 57.1%, 14.3%, 16.1% and 12.5%, respectively, while the TP risk levels of heavy pollution, moderate pollution, light pollution and clean level accounted for 62.5%, 10.7%, 21.4% and 5.4%, respectively. The average concentrations of Cr, Ni, Cu, Zn, Cd, Pb and Hg were 5.52, 7.43, 15.88, 6.70, 8.10, 1.34 and 1.12 times higher than the background values of heavy metals in Guangdong Province, respectively. Correlation analysis and principal component analysis suggested that Cr, Ni, Cu, Zn, Cd and Pb mainly came from papermaking and electroplating industries; Hg mainly came from battery or metal manufacturing industries; As did not exceed the standard, mainly came from pesticides and fertilizers; the geoaccumulation index showed that Cu, Ni and Cr were seriously polluted; the potential ecological hazard index showed that Cd and Cu were the main ecological hazard contributing factors. The results could provide decision support for water quality security of rivers as drinking water sources.
In order to find out the risk distribution of nitrogen, phosphorus and heavy metals in the surface sediments of the heavily polluted tributaries in Shahe basin, a tributary of Dongjiang River, different risk assessment methods were used. The comprehensive pollution index analysis showed that TN risk levels of heavy pollution, moderate pollution, light pollution and clean accounted for 57.1%, 14.3%, 16.1% and 12.5%, respectively, while the TP risk levels of heavy pollution, moderate pollution, light pollution and clean level accounted for 62.5%, 10.7%, 21.4% and 5.4%, respectively. The average concentrations of Cr, Ni, Cu, Zn, Cd, Pb and Hg were 5.52, 7.43, 15.88, 6.70, 8.10, 1.34 and 1.12 times higher than the background values of heavy metals in Guangdong Province, respectively. Correlation analysis and principal component analysis suggested that Cr, Ni, Cu, Zn, Cd and Pb mainly came from papermaking and electroplating industries; Hg mainly came from battery or metal manufacturing industries; As did not exceed the standard, mainly came from pesticides and fertilizers; the geoaccumulation index showed that Cu, Ni and Cr were seriously polluted; the potential ecological hazard index showed that Cd and Cu were the main ecological hazard contributing factors. The results could provide decision support for water quality security of rivers as drinking water sources.
2022, 40(1): 117-122,160.
doi: 10.13205/j.hjgc.202201017
Abstract:
To explore the spatio-temporal regular variation of water quality in typical sluice-controlled rivers of cities along the Yangtze River, and to provide support for hydro-ecological conservancy and precise regulation, the two-step clustering method was applied to the research on the spatio-temporal variation of water quality in the Nanjing reach of Qinhuai River. The results showed that, in recent years, the Nanjing reach was mainly polluted by nitrogen and phosphorus, and the water quality could be grouped into three types(i.e., Type 1-Better water quality, Type 2-medium water quality, and Type 3-poor water quality). In space, the direction of the river was closely related to the variation trend of water quality. From upstream to downstream, the average annual proportion of Type 3 water body increased from 15% to 38%, along the six sections except the section at the mouth of the Qinhuai River, indicating the gradual increase of water pollution degree. In time, the proportion of Type 3 water body decreased from 31%(2008) to 1%(2015), showing that the water quality continued to improve. In addition, the water quality was better in summer and autumn. To improve the water quality in the sluice-controlled river, the opening frequency of sluice at the mouth of the Qinhuai River could be increased under the premise of ensuring no waterlogging in the urban river, and the intensity of water diversion in winter and spring should be strengthened.
To explore the spatio-temporal regular variation of water quality in typical sluice-controlled rivers of cities along the Yangtze River, and to provide support for hydro-ecological conservancy and precise regulation, the two-step clustering method was applied to the research on the spatio-temporal variation of water quality in the Nanjing reach of Qinhuai River. The results showed that, in recent years, the Nanjing reach was mainly polluted by nitrogen and phosphorus, and the water quality could be grouped into three types(i.e., Type 1-Better water quality, Type 2-medium water quality, and Type 3-poor water quality). In space, the direction of the river was closely related to the variation trend of water quality. From upstream to downstream, the average annual proportion of Type 3 water body increased from 15% to 38%, along the six sections except the section at the mouth of the Qinhuai River, indicating the gradual increase of water pollution degree. In time, the proportion of Type 3 water body decreased from 31%(2008) to 1%(2015), showing that the water quality continued to improve. In addition, the water quality was better in summer and autumn. To improve the water quality in the sluice-controlled river, the opening frequency of sluice at the mouth of the Qinhuai River could be increased under the premise of ensuring no waterlogging in the urban river, and the intensity of water diversion in winter and spring should be strengthened.
2022, 40(1): 123-127,147.
doi: 10.13205/j.hjgc.202201018
Abstract:
The railway transportation of coal is the main way of energy supply and regulation in China, but the related researches on the impact of fugitive coal dust during railway transportation on environment are rare. This paper studied the impact of coal dust spillage on the atmosphere, water and soil in Beijing areas during railway transportation. The results showed that the concentration of PM10 in the ambient air increased obviously and fluctuated periodically. The highest values of PM10 at urban site and tunnel site were 212, 3290 μg/m3, respectively. And the influence on ambient air decreased rapidly as a function of distance. The transport and settlement of coal dust led to the increase of suspended matters in river near the monitoring site. In addition, the surface soil samples appeared weakly acidic, and the contents of Cr, CD, Pb and other heavy metals were much higher than those of the background sites. According to the primary estimation, the emission amounts of fugitive coal dust was about 3441.46 tons per year, and annual emission in Beijing areas was about 579.73 tons. It was suggested that the gantry crane spraying technology should be adopted, and dust suppressants should be improved, with the aim to strengthen the fugitive coal dust control in the railway transportation.
The railway transportation of coal is the main way of energy supply and regulation in China, but the related researches on the impact of fugitive coal dust during railway transportation on environment are rare. This paper studied the impact of coal dust spillage on the atmosphere, water and soil in Beijing areas during railway transportation. The results showed that the concentration of PM10 in the ambient air increased obviously and fluctuated periodically. The highest values of PM10 at urban site and tunnel site were 212, 3290 μg/m3, respectively. And the influence on ambient air decreased rapidly as a function of distance. The transport and settlement of coal dust led to the increase of suspended matters in river near the monitoring site. In addition, the surface soil samples appeared weakly acidic, and the contents of Cr, CD, Pb and other heavy metals were much higher than those of the background sites. According to the primary estimation, the emission amounts of fugitive coal dust was about 3441.46 tons per year, and annual emission in Beijing areas was about 579.73 tons. It was suggested that the gantry crane spraying technology should be adopted, and dust suppressants should be improved, with the aim to strengthen the fugitive coal dust control in the railway transportation.
2022, 40(1): 128-134.
doi: 10.13205/j.hjgc.202201019
Abstract:
The concentrations of 16 priority PAHs in soil of 9 substations in Hengshui, Heibei province were detected and analyzed. Health risk assessment method for contaminated site was used to compare the health risk based on BaP carcinogenic slope factor and carcinogenic slope factor(non-carcinogenic reference dose). The results showed that the total amount of PAHs in the soil of the substation site ranged from 126.89 μg/kg to 1181.94 μg/kg, and the contents of seven carcinogenic PAHs ranged from 60.07 μg/kg to 698.5 μg/kg. The pollution level showed that the substation with mild or no pollution accounted for 66.7%, and the substation with moderate pollution level or above accounted for 33.3%. Both models showed that some of the substations had carcinogenic risk, and oral ingestion and skin contact exposure were the main ways of exposure to carcinogenic risk, with cumulative contribution rate of 91% above. The results of the two models showed that the total non-carcinogenic risk quotient of soil was smaller than the acceptable non-carcinogenic risk quotient, and the BAP toxicity assessment model would lead to a small risk quotient, which was not suitable for the risk assessment of non-carcinogenic substances. From the perspective of environmental risk control, it was considered that the health risk assessment model based on carcinogenic slope factor(non-carcinogenic reference dose) was more suitable for the health risk assessment of the contaminated soil.
The concentrations of 16 priority PAHs in soil of 9 substations in Hengshui, Heibei province were detected and analyzed. Health risk assessment method for contaminated site was used to compare the health risk based on BaP carcinogenic slope factor and carcinogenic slope factor(non-carcinogenic reference dose). The results showed that the total amount of PAHs in the soil of the substation site ranged from 126.89 μg/kg to 1181.94 μg/kg, and the contents of seven carcinogenic PAHs ranged from 60.07 μg/kg to 698.5 μg/kg. The pollution level showed that the substation with mild or no pollution accounted for 66.7%, and the substation with moderate pollution level or above accounted for 33.3%. Both models showed that some of the substations had carcinogenic risk, and oral ingestion and skin contact exposure were the main ways of exposure to carcinogenic risk, with cumulative contribution rate of 91% above. The results of the two models showed that the total non-carcinogenic risk quotient of soil was smaller than the acceptable non-carcinogenic risk quotient, and the BAP toxicity assessment model would lead to a small risk quotient, which was not suitable for the risk assessment of non-carcinogenic substances. From the perspective of environmental risk control, it was considered that the health risk assessment model based on carcinogenic slope factor(non-carcinogenic reference dose) was more suitable for the health risk assessment of the contaminated soil.
2022, 40(1): 135-140,189.
doi: 10.13205/j.hjgc.202201020
Abstract:
Taking the contaminated land left by a lead-acid battery factory in Suzhou as the research object, the types of pollutants, pollution degree and health risk in the site soil were analyzed and evaluated by using Nemero comprehensive pollution index method and human health risk assessment model, and the spatial distribution of human health risk was analyzed by Kriging interpolation method in surfer. The results showed that the main heavy metal pollutants in the plot soil were lead and arsenic. The polluted level of the metal lead(Pb) reached a heavy degree, while metal arsenic(As) was at light pollution level. Through the risk assessment of pollutants on human health, it was found that the CR value of As' s carcinogenic risk for children and adults exceeded the acceptable value of 10-6, thus there was a certain carcinogenic risk for human body. In addition, the probability of children's blood lead concentration exceeding 10 μg/dL calculated by ieubk model was as high as 68.6%, which was much higher than the safety probability limit of 5%. It was concluded that there were high health risks of heavy metals lead and As in the site, and it was necessary to repair the site soil before redevelopment and utilization.
Taking the contaminated land left by a lead-acid battery factory in Suzhou as the research object, the types of pollutants, pollution degree and health risk in the site soil were analyzed and evaluated by using Nemero comprehensive pollution index method and human health risk assessment model, and the spatial distribution of human health risk was analyzed by Kriging interpolation method in surfer. The results showed that the main heavy metal pollutants in the plot soil were lead and arsenic. The polluted level of the metal lead(Pb) reached a heavy degree, while metal arsenic(As) was at light pollution level. Through the risk assessment of pollutants on human health, it was found that the CR value of As' s carcinogenic risk for children and adults exceeded the acceptable value of 10-6, thus there was a certain carcinogenic risk for human body. In addition, the probability of children's blood lead concentration exceeding 10 μg/dL calculated by ieubk model was as high as 68.6%, which was much higher than the safety probability limit of 5%. It was concluded that there were high health risks of heavy metals lead and As in the site, and it was necessary to repair the site soil before redevelopment and utilization.
2022, 40(1): 141-147.
doi: 10.13205/j.hjgc.202201021
Abstract:
Due to the less attention to the emerging pollutant tungsten in soil, this study focused on the soil of a tungsten smelting site in Luoyang, Henan province, and used the methods of spatial interpolation, single factor index, Nemerow index and potential ecological risk index to emphatically discuss the spatial distribution characteristics and potential ecological risk of tungsten in soil. The results showed that the soil tungsten contents in S10, S05 and S06 were higher than that in other functional areas; the enrichment degree of tungsten in soil layers Ⅰ and Ⅱ was much higher than that in soil layers Ⅲ and IV; with the increasing of soil depth, the areas of S01, S02, S04, S08, S10 and S12 reflected deep enriching tungsten, while S05, S06, S07 and S11 showed an surface enriching, and S03 and S09 showed an middle enriching; except for S01 and S12, the Pi of tungsten in surface and middle layer soil were minor and mild, the Pi of tungsten in the other areas of the site reached medium level; the tungsten composite indexes(PN) of each soil layer showed that the whole soil layer was heavily polluted by tungsten; except for the surface soil tungsten in S05 area, the soil tungsten(Ei) in the other areas of the site was with a mild ecological risk; the comprehensive potential ecological risk(RI) of soil tungsten in each layer showed that the ecological risks of soil tungsten in Ⅰ and Ⅱ layers were moderate, and those in Ⅲ and IV layers were mild.
Due to the less attention to the emerging pollutant tungsten in soil, this study focused on the soil of a tungsten smelting site in Luoyang, Henan province, and used the methods of spatial interpolation, single factor index, Nemerow index and potential ecological risk index to emphatically discuss the spatial distribution characteristics and potential ecological risk of tungsten in soil. The results showed that the soil tungsten contents in S10, S05 and S06 were higher than that in other functional areas; the enrichment degree of tungsten in soil layers Ⅰ and Ⅱ was much higher than that in soil layers Ⅲ and IV; with the increasing of soil depth, the areas of S01, S02, S04, S08, S10 and S12 reflected deep enriching tungsten, while S05, S06, S07 and S11 showed an surface enriching, and S03 and S09 showed an middle enriching; except for S01 and S12, the Pi of tungsten in surface and middle layer soil were minor and mild, the Pi of tungsten in the other areas of the site reached medium level; the tungsten composite indexes(PN) of each soil layer showed that the whole soil layer was heavily polluted by tungsten; except for the surface soil tungsten in S05 area, the soil tungsten(Ei) in the other areas of the site was with a mild ecological risk; the comprehensive potential ecological risk(RI) of soil tungsten in each layer showed that the ecological risks of soil tungsten in Ⅰ and Ⅱ layers were moderate, and those in Ⅲ and IV layers were mild.
2022, 40(1): 148-154.
doi: 10.13205/j.hjgc.202201022
Abstract:
Constructed wetland has been widely used in river water purification due to its lower construction and operation cost, at the same time it has a good water quality purification effect. However, the application of constructed wetland in north China is restricted for the poor operation effect under low temperature in winter. In this paper, a multi-stage composite constructed wetland project(30000 t/d) using the process combination of physicochemical pretreatment(high efficiency sedimentation tank)+constructed wetland(subsurface flow wetland+surface flow wetland was explored, and the effect of ice insulation measures on the water purification of Longhe River under low temperature in winter was studied. The operating efficiency of the constructed wetland system from December to January was analyzed. Through the study and analysis of the operation efficiency, the results showed that the Longhe constructed wetland system has high removal efficiency of COD, NH3-N, TP and SS, which was 49.06%, 77.72%, 57.95% and 38.73% respectively through certain heat preservation measures. In addition, the removal efficiency of NH3-N, TP and SS in the cattel-reed subsurface flow wetland was better than that in the reed-cattail subsurface flow wetland, with an increase of 3.2%, 11.1% and 6.7% percentage points, respectively. However, there was no significant difference in COD removal rate between the reed-cattel-cattail subsurface flow wetland and the cattel-reed subsurface flow wetland. It showed that different plant combinations had their own advantages in removing pollutants. In conclusion, the multi-stage composite constructed wetland had a better removal effect on pollutants, which can improve the operation efficiency of constructed wetland in winter under low temperature condition, and provide references for the promotion and application of constructed wetland in northern China.
Constructed wetland has been widely used in river water purification due to its lower construction and operation cost, at the same time it has a good water quality purification effect. However, the application of constructed wetland in north China is restricted for the poor operation effect under low temperature in winter. In this paper, a multi-stage composite constructed wetland project(30000 t/d) using the process combination of physicochemical pretreatment(high efficiency sedimentation tank)+constructed wetland(subsurface flow wetland+surface flow wetland was explored, and the effect of ice insulation measures on the water purification of Longhe River under low temperature in winter was studied. The operating efficiency of the constructed wetland system from December to January was analyzed. Through the study and analysis of the operation efficiency, the results showed that the Longhe constructed wetland system has high removal efficiency of COD, NH3-N, TP and SS, which was 49.06%, 77.72%, 57.95% and 38.73% respectively through certain heat preservation measures. In addition, the removal efficiency of NH3-N, TP and SS in the cattel-reed subsurface flow wetland was better than that in the reed-cattail subsurface flow wetland, with an increase of 3.2%, 11.1% and 6.7% percentage points, respectively. However, there was no significant difference in COD removal rate between the reed-cattel-cattail subsurface flow wetland and the cattel-reed subsurface flow wetland. It showed that different plant combinations had their own advantages in removing pollutants. In conclusion, the multi-stage composite constructed wetland had a better removal effect on pollutants, which can improve the operation efficiency of constructed wetland in winter under low temperature condition, and provide references for the promotion and application of constructed wetland in northern China.
2022, 40(1): 155-160.
doi: 10.13205/j.hjgc.202201023
Abstract:
Scientific monitoring of sponge facilities operation can not only provide effective assessment for the construction of sponge city, but also give data feedback and guidance suggestion for sponge cities construction. However, there is no effective method to monitor and evaluate the operation efficiency of natural sponges. Taking the sponge pilot area of a large-scale high-speed railway transportation hub in western Hubei as an example, a monitoring system of natural sponge was established. The water penetration rate monitored by the optical fiber was the basic parameter to explore the functional relationship between it and the water content. Then a main water storage monitoring model of the system was established. Finally, under actual rainfall condition, the monitoring performance of the system in terms of runoff and water saturation early warning was evaluated. The evaluation results showed that the optical fiber sensor monitoring system was with high accuracy in runoff monitoring, and the runoff generation warning time was consistent with the actual one. The optical fiber sensing and monitoring system showed strong adaptability and excellent performance, which provided certain technical support for the automatic operation of sponge city facilities.
Scientific monitoring of sponge facilities operation can not only provide effective assessment for the construction of sponge city, but also give data feedback and guidance suggestion for sponge cities construction. However, there is no effective method to monitor and evaluate the operation efficiency of natural sponges. Taking the sponge pilot area of a large-scale high-speed railway transportation hub in western Hubei as an example, a monitoring system of natural sponge was established. The water penetration rate monitored by the optical fiber was the basic parameter to explore the functional relationship between it and the water content. Then a main water storage monitoring model of the system was established. Finally, under actual rainfall condition, the monitoring performance of the system in terms of runoff and water saturation early warning was evaluated. The evaluation results showed that the optical fiber sensor monitoring system was with high accuracy in runoff monitoring, and the runoff generation warning time was consistent with the actual one. The optical fiber sensing and monitoring system showed strong adaptability and excellent performance, which provided certain technical support for the automatic operation of sponge city facilities.
2022, 40(1): 161-168.
doi: 10.13205/j.hjgc.202201024
Abstract:
Eutrophication and algal blooms have become the main problems in lake management. Predicting chlorophyll-a concentration in water based on historical monitoring data using BP neural network is one of the main means for algal bloom early warning. However, traditional BP method has some limitations, such as low iteration speed and being easy to fall into local extremum, leading to a poor fitting result and larger prediction error. In this paper, a new model(MBP) was developed based on BP neural network by combining with the global optimization capability of Metropolis acceptance criterion, and then applied to predict the monthly average chlorophyll-a concentration of Lake Taihu.Resultsshowed that, comparing with traditional BP neural network, the improved MBP model had a relatively faster coverage velocity at the initial iteration stage, and showed lower fitting error and higher accuracy. Average prediction error of the MBP model was significantly lower than that of the traditional BP neural network. Additionally, the MBP model had a stronger robustness and stability for different data noise and smaller number of samples. This model further expanded the application of traditional BP neural network in predicting concentration of chlorophyll-a and provided a new idea for establishing an early warning system of algal bloom.
Eutrophication and algal blooms have become the main problems in lake management. Predicting chlorophyll-a concentration in water based on historical monitoring data using BP neural network is one of the main means for algal bloom early warning. However, traditional BP method has some limitations, such as low iteration speed and being easy to fall into local extremum, leading to a poor fitting result and larger prediction error. In this paper, a new model(MBP) was developed based on BP neural network by combining with the global optimization capability of Metropolis acceptance criterion, and then applied to predict the monthly average chlorophyll-a concentration of Lake Taihu.Resultsshowed that, comparing with traditional BP neural network, the improved MBP model had a relatively faster coverage velocity at the initial iteration stage, and showed lower fitting error and higher accuracy. Average prediction error of the MBP model was significantly lower than that of the traditional BP neural network. Additionally, the MBP model had a stronger robustness and stability for different data noise and smaller number of samples. This model further expanded the application of traditional BP neural network in predicting concentration of chlorophyll-a and provided a new idea for establishing an early warning system of algal bloom.
2022, 40(1): 169-174,230.
doi: 10.13205/j.hjgc.202201025
Abstract:
In order to reduce the emission of asphalt smoke to the environment, a kind of eco-friendly composite smoke suppression asphalt was developed by adding admixtures to asphalt, and its performance, mechanism, economic and environmental benefits were analyzed. Firstly, through thermogravimetric experiment, the smoke suppression effect of Sasobit and aluminum trihydrate(ATH) in single blending and compounding were analyzed, combined with the basic physical performance test, the optimal proportion of smoke suppression agent was selected, and the performance with the proportion of the admixtures was analyzed. Then, through infrared spectroscopy and thermogravimetric experiment, the functional group changes of the asphalt and admixtures and the smoke suppression laws of the admixtures were studied respectively, so as to further analyze the mechanism of the composite smoke suppression asphalt. Finally, the economic and environmental benefits were evaluated. The results showed that the optimal mixture ratio of additives was 3% of Sasobit and 20% of ATH, and the asphalt smoke production rate decreased by about 10.93%. The Brookfield rotational viscosity of the asphalt was increased, the high temperature rutting resistance was increased by about 2 times, but the low temperature performance was somewhat declined. Sasobit and ATH mainly modified asphalt through chemical modification and physical modification, respectively. Compared with adding Sasobit and ATH separately, the cost of composite modified asphalt was reduced by about 53% and 9%, respectively. At the same time, the compound smoke suppression asphalt had good environmental benefits.
In order to reduce the emission of asphalt smoke to the environment, a kind of eco-friendly composite smoke suppression asphalt was developed by adding admixtures to asphalt, and its performance, mechanism, economic and environmental benefits were analyzed. Firstly, through thermogravimetric experiment, the smoke suppression effect of Sasobit and aluminum trihydrate(ATH) in single blending and compounding were analyzed, combined with the basic physical performance test, the optimal proportion of smoke suppression agent was selected, and the performance with the proportion of the admixtures was analyzed. Then, through infrared spectroscopy and thermogravimetric experiment, the functional group changes of the asphalt and admixtures and the smoke suppression laws of the admixtures were studied respectively, so as to further analyze the mechanism of the composite smoke suppression asphalt. Finally, the economic and environmental benefits were evaluated. The results showed that the optimal mixture ratio of additives was 3% of Sasobit and 20% of ATH, and the asphalt smoke production rate decreased by about 10.93%. The Brookfield rotational viscosity of the asphalt was increased, the high temperature rutting resistance was increased by about 2 times, but the low temperature performance was somewhat declined. Sasobit and ATH mainly modified asphalt through chemical modification and physical modification, respectively. Compared with adding Sasobit and ATH separately, the cost of composite modified asphalt was reduced by about 53% and 9%, respectively. At the same time, the compound smoke suppression asphalt had good environmental benefits.
2022, 40(1): 175-183.
doi: 10.13205/j.hjgc.202201026
Abstract:
In order to improve the detection accuracy of multi-scale and different materials and ensure the robustness of waste classification, based on the existing deep convolution neural network and single-stage target detection algorithm YOLOv3, an ECA with multi-scale perception visual field attention mechanism was proposed as ECA_ ERFB_ S-YOLOv3 algorithm. The multi-scale perceptual field module was introduced in front of the algorithm detector, so that the algorithm could select the appropriate perceptual field to match the garbage objects with different scales, and the detection accuracy was improved; then, ResNet50 was used to replace the original skeleton network Darknet53. Under the condition of transfer learning, efficient attention mechanism was used to autonomously enhance and suppress the features in ResNet50 and multi-scale sensory visual field module, which improved the robustness of the algorithm. Finally, K-means algorithm was used to regress the anchor box, and the allocation method of anchor box was designed. The results of ablation experiment showed that ECA_ ERFB_ S-YOLOV3 had higher precision and better robustness; when detecting densely stacked domestic waste, the algorithm could better meet the needs of the task and show better detection effect.
In order to improve the detection accuracy of multi-scale and different materials and ensure the robustness of waste classification, based on the existing deep convolution neural network and single-stage target detection algorithm YOLOv3, an ECA with multi-scale perception visual field attention mechanism was proposed as ECA_ ERFB_ S-YOLOv3 algorithm. The multi-scale perceptual field module was introduced in front of the algorithm detector, so that the algorithm could select the appropriate perceptual field to match the garbage objects with different scales, and the detection accuracy was improved; then, ResNet50 was used to replace the original skeleton network Darknet53. Under the condition of transfer learning, efficient attention mechanism was used to autonomously enhance and suppress the features in ResNet50 and multi-scale sensory visual field module, which improved the robustness of the algorithm. Finally, K-means algorithm was used to regress the anchor box, and the allocation method of anchor box was designed. The results of ablation experiment showed that ECA_ ERFB_ S-YOLOV3 had higher precision and better robustness; when detecting densely stacked domestic waste, the algorithm could better meet the needs of the task and show better detection effect.
2022, 40(1): 184-189.
doi: 10.13205/j.hjgc.202201027
Abstract:
The operation performance of transformer directly affects the safe and stable operation of power system. Noise is an important parameter to reflect operation condition of the transformer, so its monitoring was particularly important. In this study, a noise online monitoring system was designed and developed based on 5 G network and consisted of noise acquisition, central management and network transmission. The system interface displayed the noise area and the noise change of the substation in real time through noise monitoring map in geographic information system(GIS), and judged the operation condition of the transformer. Timely process and statistical analysis were carried out according to alarm information when noise was abnormal. The results showed that a resolution of 0.1 dB was achieved in the measurement range of 20~130 dB(A). The highest data transmission rate was 10 Gb/s using 5 G network. When fast Fourier transform(FFT) signal processing was used in the system, the test efficiency increased by 1 time and noise data collection rate was more than 95%. The noise monitoring system had high precision, and flexible and convenient operation, and could realize online real-time monitoring with wide application prospect.
The operation performance of transformer directly affects the safe and stable operation of power system. Noise is an important parameter to reflect operation condition of the transformer, so its monitoring was particularly important. In this study, a noise online monitoring system was designed and developed based on 5 G network and consisted of noise acquisition, central management and network transmission. The system interface displayed the noise area and the noise change of the substation in real time through noise monitoring map in geographic information system(GIS), and judged the operation condition of the transformer. Timely process and statistical analysis were carried out according to alarm information when noise was abnormal. The results showed that a resolution of 0.1 dB was achieved in the measurement range of 20~130 dB(A). The highest data transmission rate was 10 Gb/s using 5 G network. When fast Fourier transform(FFT) signal processing was used in the system, the test efficiency increased by 1 time and noise data collection rate was more than 95%. The noise monitoring system had high precision, and flexible and convenient operation, and could realize online real-time monitoring with wide application prospect.
2022, 40(1): 190-195.
doi: 10.13205/j.hjgc.202201028
Abstract:
ANAMMOX is a new economic and energy-saving biological nitrogen removal technology. Compared with the classical nitrification and denitrification, ANAMMOX has the advantages of small occupied area, no aeration and energy saving. Organic matter is one of the common pollutants in actual wastewater. The existence of organic matter will affect ANAMMOX.The reasons and mechanisms of organic matter in promoting and inhibiting ANAMMOX process are summarized by combing the research situation of organic matter's influence on ANAMMOX at home and abroad in recent years, meanwhile, the methods of relieving the inhibition of anaerobic ammonium oxidation by organic matter by reducing influent load, adjusting substrate nitrite nitrogen concentration and adding substances, in order to provide a theoretical basis for realizing high nitrogen removal performance of large-scale ANAMMOX process.
ANAMMOX is a new economic and energy-saving biological nitrogen removal technology. Compared with the classical nitrification and denitrification, ANAMMOX has the advantages of small occupied area, no aeration and energy saving. Organic matter is one of the common pollutants in actual wastewater. The existence of organic matter will affect ANAMMOX.The reasons and mechanisms of organic matter in promoting and inhibiting ANAMMOX process are summarized by combing the research situation of organic matter's influence on ANAMMOX at home and abroad in recent years, meanwhile, the methods of relieving the inhibition of anaerobic ammonium oxidation by organic matter by reducing influent load, adjusting substrate nitrite nitrogen concentration and adding substances, in order to provide a theoretical basis for realizing high nitrogen removal performance of large-scale ANAMMOX process.
2022, 40(1): 196-206.
doi: 10.13205/j.hjgc.202201029
Abstract:
Realizing the automatic classification of domestic waste is an effective way to solve the increasing problems on municipal solid waste(MSW). The thesis focused on the researches on waste image recognition based on computer vision in the past ten years. According to the differences of automatic waste classification methods, the current existing related research was divided into traditional machine learning methods and deep learning methods. It illustrated the machine learning method and the feature extraction method of the deep learning method, compared and analyzed the advantages and disadvantages of the traditional machine learning method and the waste type recognition based on the deep learning method, focused on the application research of the general neural network of the deep learning method. In addition, the data sets used in the current research on waste image recognition were introduced, and the problem of current waste image recognition were analyzed and prospected finally.
Realizing the automatic classification of domestic waste is an effective way to solve the increasing problems on municipal solid waste(MSW). The thesis focused on the researches on waste image recognition based on computer vision in the past ten years. According to the differences of automatic waste classification methods, the current existing related research was divided into traditional machine learning methods and deep learning methods. It illustrated the machine learning method and the feature extraction method of the deep learning method, compared and analyzed the advantages and disadvantages of the traditional machine learning method and the waste type recognition based on the deep learning method, focused on the application research of the general neural network of the deep learning method. In addition, the data sets used in the current research on waste image recognition were introduced, and the problem of current waste image recognition were analyzed and prospected finally.
2022, 40(1): 207-215.
doi: 10.13205/j.hjgc.202201030
Abstract:
Based on the Web of Science Core Collection(SCIE) database, this paper used the visualization software CiteSpace to conduct a visual analysis of the publishing organizations, authors, keywords, etc. of the documents related to carbon emissions in iron & steel industry from 1991 to 2021, to explore the research characteristics and development context, and to provide reference for the research and practice of carbon emissions in iron & steel industry in China in the future. The results showed that: 1) the scientific research forces cored by China, the United States, the United Kingdom and Japan, etc., contributed the main research achievements in this field; 2) The research hotspots could be mainly summarized as follows: climate change, production technology and future scenario analysis; 3) The research context of carbon emissions in iron & steel industry gradually evolved from theoretical framework and factor analysis to research background and data-oriented empirical analysis.
Based on the Web of Science Core Collection(SCIE) database, this paper used the visualization software CiteSpace to conduct a visual analysis of the publishing organizations, authors, keywords, etc. of the documents related to carbon emissions in iron & steel industry from 1991 to 2021, to explore the research characteristics and development context, and to provide reference for the research and practice of carbon emissions in iron & steel industry in China in the future. The results showed that: 1) the scientific research forces cored by China, the United States, the United Kingdom and Japan, etc., contributed the main research achievements in this field; 2) The research hotspots could be mainly summarized as follows: climate change, production technology and future scenario analysis; 3) The research context of carbon emissions in iron & steel industry gradually evolved from theoretical framework and factor analysis to research background and data-oriented empirical analysis.
2022, 40(1): 224-230.
doi: 10.13205/j.hjgc.202201032
Abstract:
The differences of development scenarios and the change of environmental conditions may lead to the re-release of heavy metals in the post-remediation sites, which brings potential environmental risks to the safe redevelopment of construction land. Choosing appropriate risk prevention and control technology is essential to ensure the long-term safe redevelopment of contaminated construction land. To promote its application and development in China, the materials and mechanisms of two types of risk prevention and control techniques, including physical containment and chemical stabilization, which were widely applied in the remediation of heavy metal contaminated sites were summarized. Then, the application cases of different risk prevention and control technologies in China and abroad were analyzed. Finally, the failure mechanisms of these two types of risk prevention and control technologies were discussed. Due to the high risk of heavy metal pollution and the high intensity of redevelopment in China's construction land, it was proposed that the study of green and sustainable risk prevention and control technologies should be focused on, and the establishment of long-term monitoring and retrospective evaluation system should be explored.
The differences of development scenarios and the change of environmental conditions may lead to the re-release of heavy metals in the post-remediation sites, which brings potential environmental risks to the safe redevelopment of construction land. Choosing appropriate risk prevention and control technology is essential to ensure the long-term safe redevelopment of contaminated construction land. To promote its application and development in China, the materials and mechanisms of two types of risk prevention and control techniques, including physical containment and chemical stabilization, which were widely applied in the remediation of heavy metal contaminated sites were summarized. Then, the application cases of different risk prevention and control technologies in China and abroad were analyzed. Finally, the failure mechanisms of these two types of risk prevention and control technologies were discussed. Due to the high risk of heavy metal pollution and the high intensity of redevelopment in China's construction land, it was proposed that the study of green and sustainable risk prevention and control technologies should be focused on, and the establishment of long-term monitoring and retrospective evaluation system should be explored.
2022, 40(1): 231-232.
Abstract:
