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2020 Vol. 38, No. 10
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2020, 38(10): 1-6.
doi: 10.13205/j.hjgc.202010001
Abstract:
To explore the characteristics and sources of surface water hydrochemistry in semi-arid areas, we analyzed the main ion composition characteristics and sources of surface water in Lake Baiyangdian basin, using hrochemical technics such as Piper Triangular diagrams and Gibbs water-rock model. The results showed that the pH of the surface water in the Lake Baiyangdian basin varied from 7.56 to 8.23, which was weakly alkaline. And the total dissolved solids, was 100 mg/L to 650 mg/L in different regions of the basin, ranking as Lake Baiyangdian > downstream > dpstream. The cations in the surface water of Lake Baiyangdian basin were mainly Na+ and Ca2+, which accounted for 76.60% of the total cations. And the anions were mainly HCO3-, which accounted for about 61.52% of total anions. The water chemistry types of surface water were HCO3-Ca in upstream, and HCO3·SO4·Cl-Na·Ca in downstream and Lake Baiyangdian. The hydrogeochemical process of Lake Baiyangdian basin was controlled by both human activities and natural functions. For natural sources, the ions of the surface water of the Lake Baiyangdian basin originated from rock weathering, carbonate weathering and silicate weathering mainly, which also affected by evaporation-crystallization.
To explore the characteristics and sources of surface water hydrochemistry in semi-arid areas, we analyzed the main ion composition characteristics and sources of surface water in Lake Baiyangdian basin, using hrochemical technics such as Piper Triangular diagrams and Gibbs water-rock model. The results showed that the pH of the surface water in the Lake Baiyangdian basin varied from 7.56 to 8.23, which was weakly alkaline. And the total dissolved solids, was 100 mg/L to 650 mg/L in different regions of the basin, ranking as Lake Baiyangdian > downstream > dpstream. The cations in the surface water of Lake Baiyangdian basin were mainly Na+ and Ca2+, which accounted for 76.60% of the total cations. And the anions were mainly HCO3-, which accounted for about 61.52% of total anions. The water chemistry types of surface water were HCO3-Ca in upstream, and HCO3·SO4·Cl-Na·Ca in downstream and Lake Baiyangdian. The hydrogeochemical process of Lake Baiyangdian basin was controlled by both human activities and natural functions. For natural sources, the ions of the surface water of the Lake Baiyangdian basin originated from rock weathering, carbonate weathering and silicate weathering mainly, which also affected by evaporation-crystallization.
2020, 38(10): 7-13.
doi: 10.13205/j.hjgc.202010002
Abstract:
It was an important premise for sustainable management of regional water resources to accurately grasp the law of water transport and dissipation in the soil-plant-atmosphere continuum (SPAC). In this paper, the Baiyangdian wetland was taken as the research area. Combined with field measurement and model simulation method, influences of groundwater depth change on the water transport and dissipation in the SPAC system of Phragmites australis were discussed. The main conclusions of this study was as follows:1) Evapotranspiration of Phragmites australis (ETa) decreased with the increase of groundwater depth, and the threshold of groundwater depth for ETa to decrease was about 100 cm. With the decrease of groundwater depth, the soil profile balance during the whole growing season changed from water deficit to surplus. The groundwater burial depth threshold value that soil profile balance changed from water deficit to surplus was 60 cm, and the deficit amount was positively related to groundwater burial depth. 2) The effect levels of groundwater depth change on soil water storage and evapotranspiration in different months were different, and they reached peak in June. A large amount of ecological water replenishment should be avoided in spring and before the flood season, and the recommended water replenishment timings was autumn and winter. 3) With a comprehensive consideration of vegetation growth demand and water conservation, the optimal groundwater depth range of Phragmites australis communities was 110~150 cm in Baiyangdian wetland. Under the optimal scenario, the evapotranspiration of Phragmites australis communities in the growing season had 10%~20% water-saving potential.
It was an important premise for sustainable management of regional water resources to accurately grasp the law of water transport and dissipation in the soil-plant-atmosphere continuum (SPAC). In this paper, the Baiyangdian wetland was taken as the research area. Combined with field measurement and model simulation method, influences of groundwater depth change on the water transport and dissipation in the SPAC system of Phragmites australis were discussed. The main conclusions of this study was as follows:1) Evapotranspiration of Phragmites australis (ETa) decreased with the increase of groundwater depth, and the threshold of groundwater depth for ETa to decrease was about 100 cm. With the decrease of groundwater depth, the soil profile balance during the whole growing season changed from water deficit to surplus. The groundwater burial depth threshold value that soil profile balance changed from water deficit to surplus was 60 cm, and the deficit amount was positively related to groundwater burial depth. 2) The effect levels of groundwater depth change on soil water storage and evapotranspiration in different months were different, and they reached peak in June. A large amount of ecological water replenishment should be avoided in spring and before the flood season, and the recommended water replenishment timings was autumn and winter. 3) With a comprehensive consideration of vegetation growth demand and water conservation, the optimal groundwater depth range of Phragmites australis communities was 110~150 cm in Baiyangdian wetland. Under the optimal scenario, the evapotranspiration of Phragmites australis communities in the growing season had 10%~20% water-saving potential.
2020, 38(10): 14-20.
doi: 10.13205/j.hjgc.202010003
Abstract:
Using the digital filtering method with the improved regression constant-Chapman-Maxwell, the baseflow was separated from daily streamflow in the four hydrological stations in the Baiyangdian Basin. Monthly anomalies of three specific hydrometeorological variables (precipitation, streamflow, and baseflow) were used to analyze the hydrological drought response (runoff drought and baseflow drought) to extreme meteorological drought process. The results showed that: 1) annual precipitation in the Baiyangdian Basin presented decreasing trends with a rate of 1.81 mm/a, and a downward abrupt change was found around 1979, which resulted in about 8% of precipitation decrease. Consistent with the decreasing trend in precipitation, an extreme meteorological drought was also detected, and ranged from August 1996 to May 2011; 2)hydrological drought, resulting from meteorological drought, exhibited a time lag and had a longer drought duration and greater drought intensity, suggesting a nonstationarity in the rainfall-runoff relationship during a prolonged drought; 3)hydrological recovery lagged behind meteorological recovery by about an average of 55 months, and baseflow recovery lagged the runoff recovery. All of these results can help to understand the hydrological response to climate change better, and provide certain theoretical and practical references for calculating river ecological water demand and maintaining river ecosystem health.
Using the digital filtering method with the improved regression constant-Chapman-Maxwell, the baseflow was separated from daily streamflow in the four hydrological stations in the Baiyangdian Basin. Monthly anomalies of three specific hydrometeorological variables (precipitation, streamflow, and baseflow) were used to analyze the hydrological drought response (runoff drought and baseflow drought) to extreme meteorological drought process. The results showed that: 1) annual precipitation in the Baiyangdian Basin presented decreasing trends with a rate of 1.81 mm/a, and a downward abrupt change was found around 1979, which resulted in about 8% of precipitation decrease. Consistent with the decreasing trend in precipitation, an extreme meteorological drought was also detected, and ranged from August 1996 to May 2011; 2)hydrological drought, resulting from meteorological drought, exhibited a time lag and had a longer drought duration and greater drought intensity, suggesting a nonstationarity in the rainfall-runoff relationship during a prolonged drought; 3)hydrological recovery lagged behind meteorological recovery by about an average of 55 months, and baseflow recovery lagged the runoff recovery. All of these results can help to understand the hydrological response to climate change better, and provide certain theoretical and practical references for calculating river ecological water demand and maintaining river ecosystem health.
2020, 38(10): 21-25.
doi: 10.13205/j.hjgc.202010004
Abstract:
In order to explore the comprehensive ecological environment of Bosten Lake basin, based on the water quality and water quantity biological data of Bosten Lake and Kaidu River of 2000—2018, this paper used fuzzy evaluation mathematical model to evaluate the current water system situation of the basin, analyzed the water quantity of Bosten Lake and Kaidu River, and preliminarily proposed the optimal control method of water system. The results showed that the water flow of the Kaidu River and the water level of the Bosten Lake in 2000—2018 showed a trend of decreasing first and then increasing. After 2014, the water volume of the Bosten Lake Basin began to surplus; the degree of ecological water demand in Bosten Lake Basin was poor on the whole, showing a tendency of gradual recovery after deterioration. Aiming at the status quo of the water system connection of the Bosten Lake, the basic regulation methods of the Bosten Lake water system with increasing path, in-situ strengthening and node regulation were proposed. The water demand regulation could meet the ecological water demand of the Bosten Lake and increase the ecological water supply of the Peacock River. The scientific combination of the three control methods provided better protection for the water quality of the Bosten Lake, and the industrial, agricultural and domestic water supply of downstream of the Peacock River.
In order to explore the comprehensive ecological environment of Bosten Lake basin, based on the water quality and water quantity biological data of Bosten Lake and Kaidu River of 2000—2018, this paper used fuzzy evaluation mathematical model to evaluate the current water system situation of the basin, analyzed the water quantity of Bosten Lake and Kaidu River, and preliminarily proposed the optimal control method of water system. The results showed that the water flow of the Kaidu River and the water level of the Bosten Lake in 2000—2018 showed a trend of decreasing first and then increasing. After 2014, the water volume of the Bosten Lake Basin began to surplus; the degree of ecological water demand in Bosten Lake Basin was poor on the whole, showing a tendency of gradual recovery after deterioration. Aiming at the status quo of the water system connection of the Bosten Lake, the basic regulation methods of the Bosten Lake water system with increasing path, in-situ strengthening and node regulation were proposed. The water demand regulation could meet the ecological water demand of the Bosten Lake and increase the ecological water supply of the Peacock River. The scientific combination of the three control methods provided better protection for the water quality of the Bosten Lake, and the industrial, agricultural and domestic water supply of downstream of the Peacock River.
2020, 38(10): 26-32,60.
doi: 10.13205/j.hjgc.202010005
Abstract:
In recent years, ecological problems occurred due to the large fluctuations in the water level of Xiaohu Lake distinct in Bosten Lake. Therefore, analysis of water deficit relying on the lowest ecological water level, has a positive significance for the water regulation and ecological protection for Xiaohu Lake. Based on the measured Xiaohu Lake water level data in Dawuti sluice from 1991 to 2019, this study combined with the DEM data and remote sensing inversion NDVI data of the lake basin, using the annual guarantee rate setting method, lake morphology analytic approach and curve correlation method, to calculate the minimum water level in Xiaohu Lake. Relying on the ecological water level data, combined with hydrological, meteorological and agricultural activities, and water regulation data in the lake area, the main driving factors for water scarcity in Xiaohu Lake were analyzed using principal component analysis. The results showed that the minimum ecological water level of Bosten Lake was 1047.18 m, and the average satisfaction rate for many years was 31.03%. In year 1991—1997, 2005—2015, 2017, ecological water shortage occurred in the Bosten Xiaohu Lake District, with an average water shortage of 0.69×108 m3. The amount of upstream water was the main factor for the ecological water demand of Xiaohu Lake District, followed by agricultural activities, water regulation activities of Baolangsumu and the impact of climate change was relatively slighter. Before 2000, the ecological water shortage was mainly due to the regulation of the water level in the lake area; after 2000, agricultural water withdrawal in the irrigation area became the main cause of ecological water shortage. Scientific evidences could be provided by the research for the regulation of the water volume of Xiaohu Lake District of Bosten Lake and the restoration and protection of the wetland ecosystem.
In recent years, ecological problems occurred due to the large fluctuations in the water level of Xiaohu Lake distinct in Bosten Lake. Therefore, analysis of water deficit relying on the lowest ecological water level, has a positive significance for the water regulation and ecological protection for Xiaohu Lake. Based on the measured Xiaohu Lake water level data in Dawuti sluice from 1991 to 2019, this study combined with the DEM data and remote sensing inversion NDVI data of the lake basin, using the annual guarantee rate setting method, lake morphology analytic approach and curve correlation method, to calculate the minimum water level in Xiaohu Lake. Relying on the ecological water level data, combined with hydrological, meteorological and agricultural activities, and water regulation data in the lake area, the main driving factors for water scarcity in Xiaohu Lake were analyzed using principal component analysis. The results showed that the minimum ecological water level of Bosten Lake was 1047.18 m, and the average satisfaction rate for many years was 31.03%. In year 1991—1997, 2005—2015, 2017, ecological water shortage occurred in the Bosten Xiaohu Lake District, with an average water shortage of 0.69×108 m3. The amount of upstream water was the main factor for the ecological water demand of Xiaohu Lake District, followed by agricultural activities, water regulation activities of Baolangsumu and the impact of climate change was relatively slighter. Before 2000, the ecological water shortage was mainly due to the regulation of the water level in the lake area; after 2000, agricultural water withdrawal in the irrigation area became the main cause of ecological water shortage. Scientific evidences could be provided by the research for the regulation of the water volume of Xiaohu Lake District of Bosten Lake and the restoration and protection of the wetland ecosystem.
2020, 38(10): 33-40.
doi: 10.13205/j.hjgc.202010006
Abstract:
The two-dimensional hydrodynamic water environment numerical simulation method was used to study the influence of sewage discharge from Yuyao sewage plant on water environment, when multiple water functional zones coexisted in Hangzhou bay estuary. And the influence of envelope range, plane distribution characteristics of CODMn, NH3-N and TP on each water functional zone were analyzed. The results showed that when the single increment of pollutants was discharged normally, the pollution zone formed a thin and long pattern along the direction of water flow. The enveloping area of the pollution zone with equal concentration was larger than neap tide, the maximum value was significantly larger than the average value, and the pollution area in the accident condition was larger than that in the normal condition. Combining the discharged from the other pollution sources and environmental background, the mixing area of the discharge outlet was 0.20 km2, which met the coresponding requirements. According to the environmental impact assessment method of multi-functional areas, the most stringent water quality management objectives were met, and the marine function zoning and water quality classification management objective of a seawater function zoning was not affected. This research case was typical in practical engineering application. The results could provide reference for similar projects such as the demonstration of sewage outlet site selection in tidal estuary and simulation of water environment impact.
The two-dimensional hydrodynamic water environment numerical simulation method was used to study the influence of sewage discharge from Yuyao sewage plant on water environment, when multiple water functional zones coexisted in Hangzhou bay estuary. And the influence of envelope range, plane distribution characteristics of CODMn, NH3-N and TP on each water functional zone were analyzed. The results showed that when the single increment of pollutants was discharged normally, the pollution zone formed a thin and long pattern along the direction of water flow. The enveloping area of the pollution zone with equal concentration was larger than neap tide, the maximum value was significantly larger than the average value, and the pollution area in the accident condition was larger than that in the normal condition. Combining the discharged from the other pollution sources and environmental background, the mixing area of the discharge outlet was 0.20 km2, which met the coresponding requirements. According to the environmental impact assessment method of multi-functional areas, the most stringent water quality management objectives were met, and the marine function zoning and water quality classification management objective of a seawater function zoning was not affected. This research case was typical in practical engineering application. The results could provide reference for similar projects such as the demonstration of sewage outlet site selection in tidal estuary and simulation of water environment impact.
2020, 38(10): 41-46.
doi: 10.13205/j.hjgc.202010007
Abstract:
The problem of ecological degradation of small and medium rivers in the northern plain area in China is prominent. The selection of appropriate ecological management technologies is conducive to improving the relevance and scientificity of river ecological restoration. In this paper, 21 river ecological management technologies in 5 categories were summarized. An index system, including 3 elements technical feasibility, economic rationality and governance effect and 9 indicators, were established. A screening method based on the comprehensive index and four-level screening criteria, described as very-suitable, suitable, sub-suitable, unsuitable was proposed to screen out ecological management technologies, and provide support for river ecological management.
The problem of ecological degradation of small and medium rivers in the northern plain area in China is prominent. The selection of appropriate ecological management technologies is conducive to improving the relevance and scientificity of river ecological restoration. In this paper, 21 river ecological management technologies in 5 categories were summarized. An index system, including 3 elements technical feasibility, economic rationality and governance effect and 9 indicators, were established. A screening method based on the comprehensive index and four-level screening criteria, described as very-suitable, suitable, sub-suitable, unsuitable was proposed to screen out ecological management technologies, and provide support for river ecological management.
2020, 38(10): 47-52.
doi: 10.13205/j.hjgc.202010008
Abstract:
With the rapid development of social economy, the contradiction of water resources has become increasingly prominent. Therefore, it is of great significance to coordinate water resources conflicts. Based on the analysis of river water resources conflicts, a coordinated framework of water resources conflicts in China is constructed. Taking the Jinjiang River Basin as an example, we classified the types of water resources conflicts in the the Jinjiang River Basin into water quality type and process type, analyzed and calculated the water ecdogical rigid water demand, rigid elastic water demand and elastic water demand, and adopted the multi-objective optimization method to determine the coordinated water quality water transfer scheme that contradicts the process. The water resources conflict coordination framework can provide theoretical basis and technical support for water resource conflict management.
With the rapid development of social economy, the contradiction of water resources has become increasingly prominent. Therefore, it is of great significance to coordinate water resources conflicts. Based on the analysis of river water resources conflicts, a coordinated framework of water resources conflicts in China is constructed. Taking the Jinjiang River Basin as an example, we classified the types of water resources conflicts in the the Jinjiang River Basin into water quality type and process type, analyzed and calculated the water ecdogical rigid water demand, rigid elastic water demand and elastic water demand, and adopted the multi-objective optimization method to determine the coordinated water quality water transfer scheme that contradicts the process. The water resources conflict coordination framework can provide theoretical basis and technical support for water resource conflict management.
2020, 38(10): 53-60.
doi: 10.13205/j.hjgc.202010009
Abstract:
The amplitude, frequency, duration, and regularity of lake water level fluctuations are the key factors affecting the status of lake aquatic vegetation and the allocation of water resources. Previous studies mainly identified the main ecological impacts by selecting some water level change indicators. To maintain the ecological health of lakes and carry out reasonable water level control, it is necessary to integrate multiple indicators of water level changes and analyze the response characteristics of lake plants to lake water level changes as a whole. Taking the Hongze Lake as an example, based on the IHA/RVA method, this paper focused on the analysis of the influence of the Hongze Lake water level changes on emergent plants after the first phase of the East Route of the South-to-North Water Diversion Project. The results showed that after the first phase of the East Route of the South-to-North Water Diversion Project, the Hongze Lake’s monthly average water level in March, May, July and September and the minimum 30-day average water level changed in height, which had the most significant impact on the area of emergent plants. For the other IHA indicators, the degree of change was small and the impact was not obvious. When the average water level in March exceeded 13.4 m, the germination of emergent plants was significantly inhibited; when the average water level in May was 13.1 m and the average water level in July was 12.7 m, the area of emergent plants increased significantly; when the average water level in September was higher than 13.4 m, the area of emergent plants was greatly reduced; when the minimum 30-day average water level was less than 12.0 m, the area of emergent plants decreased by 14.32 km2 on average. From the perspective of maintaining the area of emergent plants, and the reverse seasonal hydrological process of the Hongze Lake to meet the needs of the growth and reproduction of emergent plants, the suitable ecological water levels in March, May, July and September should be determined at 13.20 m, 13.10 m, 12.70 m and 12.85 m, respectively.
The amplitude, frequency, duration, and regularity of lake water level fluctuations are the key factors affecting the status of lake aquatic vegetation and the allocation of water resources. Previous studies mainly identified the main ecological impacts by selecting some water level change indicators. To maintain the ecological health of lakes and carry out reasonable water level control, it is necessary to integrate multiple indicators of water level changes and analyze the response characteristics of lake plants to lake water level changes as a whole. Taking the Hongze Lake as an example, based on the IHA/RVA method, this paper focused on the analysis of the influence of the Hongze Lake water level changes on emergent plants after the first phase of the East Route of the South-to-North Water Diversion Project. The results showed that after the first phase of the East Route of the South-to-North Water Diversion Project, the Hongze Lake’s monthly average water level in March, May, July and September and the minimum 30-day average water level changed in height, which had the most significant impact on the area of emergent plants. For the other IHA indicators, the degree of change was small and the impact was not obvious. When the average water level in March exceeded 13.4 m, the germination of emergent plants was significantly inhibited; when the average water level in May was 13.1 m and the average water level in July was 12.7 m, the area of emergent plants increased significantly; when the average water level in September was higher than 13.4 m, the area of emergent plants was greatly reduced; when the minimum 30-day average water level was less than 12.0 m, the area of emergent plants decreased by 14.32 km2 on average. From the perspective of maintaining the area of emergent plants, and the reverse seasonal hydrological process of the Hongze Lake to meet the needs of the growth and reproduction of emergent plants, the suitable ecological water levels in March, May, July and September should be determined at 13.20 m, 13.10 m, 12.70 m and 12.85 m, respectively.
2020, 38(10): 61-67.
doi: 10.13205/j.hjgc.202010010
Abstract:
In order to assess the risk of groundwater over-exploitation and encroachment of ecological water demand of rivers on water sustainability, this study took the Huanghuaihai Basin as the research area, used the non-stationary Budyko model as well as the water balance formula, and combined the results of ecological water demand accounting and water consumption data from various sectors. The BlWSI index was chosen to evaluate the water sustainability of the Huanghuaihai Basin based on consumptive blue water use (CBWU), nonrenewable groundwater abstraction (NRGWA), and surface water over-abstraction (SWOA). The results showed that the BlWSI indicators which characterized the sustainability of blue water resources had significant spatial and temporal variability in the Huanghuaihai Basin. Among the three river basins, the Yellow River Basin has the lowest degree of water sustainability, followed by the Haihe River Basin, and the Huaihe River Basin had the highest degree of sustainability. During the period of 1960—2000, the sustainability of water resources in the Huanghuaihai Basin showed an increasing trend in different degrees. This study was an important theoretical reference for improving sustainable water resources management in the Huanghuaihai Basin.
In order to assess the risk of groundwater over-exploitation and encroachment of ecological water demand of rivers on water sustainability, this study took the Huanghuaihai Basin as the research area, used the non-stationary Budyko model as well as the water balance formula, and combined the results of ecological water demand accounting and water consumption data from various sectors. The BlWSI index was chosen to evaluate the water sustainability of the Huanghuaihai Basin based on consumptive blue water use (CBWU), nonrenewable groundwater abstraction (NRGWA), and surface water over-abstraction (SWOA). The results showed that the BlWSI indicators which characterized the sustainability of blue water resources had significant spatial and temporal variability in the Huanghuaihai Basin. Among the three river basins, the Yellow River Basin has the lowest degree of water sustainability, followed by the Haihe River Basin, and the Huaihe River Basin had the highest degree of sustainability. During the period of 1960—2000, the sustainability of water resources in the Huanghuaihai Basin showed an increasing trend in different degrees. This study was an important theoretical reference for improving sustainable water resources management in the Huanghuaihai Basin.
2020, 38(10): 68-75.
doi: 10.13205/j.hjgc.202010011
Abstract:
The pollution levels, spatial distribution, and human health risks of heavy metals in aquatic environment of a typical wetland in Sanjiang Plain were investigated and evaluated. The concentrations of Cu, Cr, Cd, Zn, and Ni were detected in multi-media (water, sediment, and wild fish species) collected from Qixing River wetland. The results showed that the average concentration of heavy metals were in the sequence of Zn (28.0) > Cr (4.5) > Cu (3.2) > Ni (2.6) > Cd (0.1) in water (μg/L), and Zn (139.4) > Cr (81.9) > Ni (45.7) > Cu (24.4) > Cd (0.2) in sediments (mg/kg). All concentrations of heavy metals measured in the water samples were lower than China’s National Standard of Surface Water Quality I, while the concentrations of Zn and Cd in sediments were elevated and compared to the soil environmental background value of Heilongjiang. Except for the concentration of Ni in Perccottus glenii samples were below the detection limit, all the heavy metals were detected in the wild fish species. And moderate accumulation of Zn was found in Cobitis granoe, while the four other heavy metals in wild fish species were in low accumulation status. The single risk factor (CF), taking the Aquatic Life Water Permissible Limits and Sediments Quality Guideline as the reference value, indicated a high risk threat to the aquatic organisms as affected by Cr alone, and Cr contributed most to the comprehensive risk index (PLI). The target hazard quotients (THQ) and hazard indexes (HI) of these five heavy metals were bellow 1, indicating that there was no non-carcinogenic risk via consumption of wild fish; while the carcinogenic risk metrics (CR) of Cd exceeded the cancer risk threshold (10-5), indicative in elevation of cancer incidence in local consumers.
The pollution levels, spatial distribution, and human health risks of heavy metals in aquatic environment of a typical wetland in Sanjiang Plain were investigated and evaluated. The concentrations of Cu, Cr, Cd, Zn, and Ni were detected in multi-media (water, sediment, and wild fish species) collected from Qixing River wetland. The results showed that the average concentration of heavy metals were in the sequence of Zn (28.0) > Cr (4.5) > Cu (3.2) > Ni (2.6) > Cd (0.1) in water (μg/L), and Zn (139.4) > Cr (81.9) > Ni (45.7) > Cu (24.4) > Cd (0.2) in sediments (mg/kg). All concentrations of heavy metals measured in the water samples were lower than China’s National Standard of Surface Water Quality I, while the concentrations of Zn and Cd in sediments were elevated and compared to the soil environmental background value of Heilongjiang. Except for the concentration of Ni in Perccottus glenii samples were below the detection limit, all the heavy metals were detected in the wild fish species. And moderate accumulation of Zn was found in Cobitis granoe, while the four other heavy metals in wild fish species were in low accumulation status. The single risk factor (CF), taking the Aquatic Life Water Permissible Limits and Sediments Quality Guideline as the reference value, indicated a high risk threat to the aquatic organisms as affected by Cr alone, and Cr contributed most to the comprehensive risk index (PLI). The target hazard quotients (THQ) and hazard indexes (HI) of these five heavy metals were bellow 1, indicating that there was no non-carcinogenic risk via consumption of wild fish; while the carcinogenic risk metrics (CR) of Cd exceeded the cancer risk threshold (10-5), indicative in elevation of cancer incidence in local consumers.
2020, 38(10): 76-82.
doi: 10.13205/j.hjgc.202010012
Abstract:
Environmental flow (e-flow) management is very important for protecting downstream riverine ecosystem. In the research of reservoir ecological operation, in order to provide different e-flows for different periods, the e-flow management becomes more and more complicated. People tend to adopt more complicated e-flow management to improve ecological flow regime. However, not only e-flow management affects ecological flow regime, reservoir inflow classification also influences ecological flow regime, and further influences the results of e-flow management. Studying the effect of flow classifications on the results of e-flow management is helpful to choose the better e-flow management before reservoir operation, especially when it is necessary to consider investment cost. In this paper, through the analysis of global streamflows, three types of inflow sequences were summarized. To compare different e-flow management strategies, we adopted four universal e-flow management strategies. This paper draw some general conclusions. When reservoir inflows was distributed evenly during the whole year, the change of e-flow management strategies wouldn’t affect ecological flow regime. Thus, the reservoir inflows in this type were not sensitive to the change of e-flow management strategies.
Environmental flow (e-flow) management is very important for protecting downstream riverine ecosystem. In the research of reservoir ecological operation, in order to provide different e-flows for different periods, the e-flow management becomes more and more complicated. People tend to adopt more complicated e-flow management to improve ecological flow regime. However, not only e-flow management affects ecological flow regime, reservoir inflow classification also influences ecological flow regime, and further influences the results of e-flow management. Studying the effect of flow classifications on the results of e-flow management is helpful to choose the better e-flow management before reservoir operation, especially when it is necessary to consider investment cost. In this paper, through the analysis of global streamflows, three types of inflow sequences were summarized. To compare different e-flow management strategies, we adopted four universal e-flow management strategies. This paper draw some general conclusions. When reservoir inflows was distributed evenly during the whole year, the change of e-flow management strategies wouldn’t affect ecological flow regime. Thus, the reservoir inflows in this type were not sensitive to the change of e-flow management strategies.
2020, 38(10): 83-89.
doi: 10.13205/j.hjgc.202010013
Abstract:
Exploring the influence of parameter sensitivity and uncertainty of the hydrological model on runoff simulation has considerable significance. This study used the SWAT model to simulate the surface runoff process in the Naoli River Basin. The SUFI-2 method was used to evaluate the influence of the model parameter sensitivity and uncertainty on the simulation results, while the coefficient of determination (R2) and Nash-Sutcliffe efficiency coefficient (ENS) were selected to evaluate the accuracy of the model. The sensitivity analysis results showed that the four parameters, including the number of CN2.mgt, SLSUBBSN.hru, SOL_BD.sol, and SOL_K.sol were the most significant parameters for the runoff simulation of Naoli River Basin. It showed that CN2, soil and topography were the most important factors affecting the runoff of Naoli River Basin. The monthly runoff simulation process fitted well with the measured hydrological process, and the R2 and ENS were 0.68, 0.67 and 0.76, 0.44 during the period calibration and validation periods, respectively, which reached satisfactory level. The results of uncertainty analysis showed that the p-factor was 0.78 and the r-factor was 0.94, indicating that there was less uncertainty, which further verified the applicability of the model. The results could provide references for SWAT model application and parameter calibration in other similar basins.
Exploring the influence of parameter sensitivity and uncertainty of the hydrological model on runoff simulation has considerable significance. This study used the SWAT model to simulate the surface runoff process in the Naoli River Basin. The SUFI-2 method was used to evaluate the influence of the model parameter sensitivity and uncertainty on the simulation results, while the coefficient of determination (R2) and Nash-Sutcliffe efficiency coefficient (ENS) were selected to evaluate the accuracy of the model. The sensitivity analysis results showed that the four parameters, including the number of CN2.mgt, SLSUBBSN.hru, SOL_BD.sol, and SOL_K.sol were the most significant parameters for the runoff simulation of Naoli River Basin. It showed that CN2, soil and topography were the most important factors affecting the runoff of Naoli River Basin. The monthly runoff simulation process fitted well with the measured hydrological process, and the R2 and ENS were 0.68, 0.67 and 0.76, 0.44 during the period calibration and validation periods, respectively, which reached satisfactory level. The results of uncertainty analysis showed that the p-factor was 0.78 and the r-factor was 0.94, indicating that there was less uncertainty, which further verified the applicability of the model. The results could provide references for SWAT model application and parameter calibration in other similar basins.
2020, 38(10): 90-96.
doi: 10.13205/j.hjgc.202010014
Abstract:
In order to judge the development trend and diagnose the morbid factors of the lake water ecological health subsystem, the five element subtraction set was introduced, and the composite matrix of the ecosystem and the physical and chemical subsystem was established to get the lake water ecological health status. Thus, the dynamic diagnosis and evaluation method of the lake water ecological health based on the risk matrix and the five element subtraction set was proposed and applied to Wabu lake in Anhui province. The results showed that the water ecological health status of Wabu lake had a trend of deterioration from 1980 to 2015, which was slightly morbid in 2012 and slightly improved in 2015. It was indentified by five element subtraction set pair potential that the pathological factors of water ecological health of Wabu lake mainly included benthos, zooplankton, chlorophyll, COD, TN, TP and transparency. And they were important indicators to improve water ecological health of Wabu lake. The dynamic diagnosis and evaluation method of the coupling of the risk matrix and the five element subtraction set could provide a new idea for lake water ecological health evaluation.
In order to judge the development trend and diagnose the morbid factors of the lake water ecological health subsystem, the five element subtraction set was introduced, and the composite matrix of the ecosystem and the physical and chemical subsystem was established to get the lake water ecological health status. Thus, the dynamic diagnosis and evaluation method of the lake water ecological health based on the risk matrix and the five element subtraction set was proposed and applied to Wabu lake in Anhui province. The results showed that the water ecological health status of Wabu lake had a trend of deterioration from 1980 to 2015, which was slightly morbid in 2012 and slightly improved in 2015. It was indentified by five element subtraction set pair potential that the pathological factors of water ecological health of Wabu lake mainly included benthos, zooplankton, chlorophyll, COD, TN, TP and transparency. And they were important indicators to improve water ecological health of Wabu lake. The dynamic diagnosis and evaluation method of the coupling of the risk matrix and the five element subtraction set could provide a new idea for lake water ecological health evaluation.
2020, 38(10): 97-102,113.
doi: 10.13205/j.hjgc.202010015
Abstract:
Reclaimed water has the outstanding advantages of easy to obtain, large quantity, stable and high resource availability, and is gradually becoming an important source for landscape water. However, reclaimed water contains nutrients such as nitrogen and phosphorus, therefore exacerbates the risk of algal blooms during landscape reuse. UV-C irradiation can suppress algal growth for several days in the early growth stage, thereby is proposed as an approach for preventing algal blooms. In this study, the secondary effluent from a sewage treatment plant in Shenzhen was taken as a typical sample of reclaimed water for landscape, and the growth suppression effect of UV-C (254 nm) on a typical Chlorophyta species, Scenedesmus obliquus were investigated. The effect of UV-C doses on growth characteristics, cell membrane integrity and photosynthetic activity of S. obliquus were assessed by a flow cytometry and a PHYTO-PAM chlorophyll fluorometer. The results showed that for S. obliquus, with an initial density of about 7×104 cells/mL, UV-C irradiation at 50~100 mJ/cm2 achieved a growth inhibition period of 1~5 d, and the growth inhibition period could be further extended to 10 days at UV-C doses of 150~200 mJ/cm2. UV-C irradiation caused marked decreases in photosynthetic activity of S. obliquus immediately and caused rupture of part of the cells gradually, and the percentage of membrane damaged cells increased to 16%~71% within 10 days after 100~200 mJ/cm2 UV-C treatment. In summary, UV-C could achieve significant suppression effect on S. obliquus growth, which was a promising method for preventing and controlling the bloom risk of S. obliquus in reclaimed water.
Reclaimed water has the outstanding advantages of easy to obtain, large quantity, stable and high resource availability, and is gradually becoming an important source for landscape water. However, reclaimed water contains nutrients such as nitrogen and phosphorus, therefore exacerbates the risk of algal blooms during landscape reuse. UV-C irradiation can suppress algal growth for several days in the early growth stage, thereby is proposed as an approach for preventing algal blooms. In this study, the secondary effluent from a sewage treatment plant in Shenzhen was taken as a typical sample of reclaimed water for landscape, and the growth suppression effect of UV-C (254 nm) on a typical Chlorophyta species, Scenedesmus obliquus were investigated. The effect of UV-C doses on growth characteristics, cell membrane integrity and photosynthetic activity of S. obliquus were assessed by a flow cytometry and a PHYTO-PAM chlorophyll fluorometer. The results showed that for S. obliquus, with an initial density of about 7×104 cells/mL, UV-C irradiation at 50~100 mJ/cm2 achieved a growth inhibition period of 1~5 d, and the growth inhibition period could be further extended to 10 days at UV-C doses of 150~200 mJ/cm2. UV-C irradiation caused marked decreases in photosynthetic activity of S. obliquus immediately and caused rupture of part of the cells gradually, and the percentage of membrane damaged cells increased to 16%~71% within 10 days after 100~200 mJ/cm2 UV-C treatment. In summary, UV-C could achieve significant suppression effect on S. obliquus growth, which was a promising method for preventing and controlling the bloom risk of S. obliquus in reclaimed water.
2020, 38(10): 103-107.
doi: 10.13205/j.hjgc.202010016
Abstract:
In this study, the heterotrophic nitrification-aerobic denitrification characteristics of strain PTW21, a typical strain of a novel nitrogen removal species Massilia neuiana, was investigated. The high efficiencies of heterotrophic nitrification and aerobic denitrification by strain PTW21 were demonstrated, which were both obtained over 90%. A higher denitrification efficiency was obtained than its nitrification efficiency in the simultaneous nitrification and denitrification (SND) by strain PTW21. However, a nitrification-denitrification competitive inhibition was observed in the presence of NH4+-N that ammonium was preferentially consumed by strain PTW21, followed by nitrate. Totally over 95% of ammonia and nitrate nitrogen were removed by strain PTW21 in the SND process. The study on Massilia neuiana enriched the variety of heterotrophic nitrification-aerobic denitrification microbe, and established the preliminary foundation of the strain for the bio-augmentation application in sewage treatment plants.
In this study, the heterotrophic nitrification-aerobic denitrification characteristics of strain PTW21, a typical strain of a novel nitrogen removal species Massilia neuiana, was investigated. The high efficiencies of heterotrophic nitrification and aerobic denitrification by strain PTW21 were demonstrated, which were both obtained over 90%. A higher denitrification efficiency was obtained than its nitrification efficiency in the simultaneous nitrification and denitrification (SND) by strain PTW21. However, a nitrification-denitrification competitive inhibition was observed in the presence of NH4+-N that ammonium was preferentially consumed by strain PTW21, followed by nitrate. Totally over 95% of ammonia and nitrate nitrogen were removed by strain PTW21 in the SND process. The study on Massilia neuiana enriched the variety of heterotrophic nitrification-aerobic denitrification microbe, and established the preliminary foundation of the strain for the bio-augmentation application in sewage treatment plants.
2020, 38(10): 108-113.
doi: 10.13205/j.hjgc.202010017
Abstract:
In view of the low biological denitrification efficiency of low-temperature sewage, the low-temperature sewage was treated by an organic polymer composite hard particle bio-carrier(OPCRP)-SBMBBR reactor. Compared with the traditional SBR reactor, two sets of reactors were analyzed by Miseq high-throughput sequencing technology. The difference in bacterial flora diversity and compositional abundance of activated sludge in the medium revealed the efficient treatment of the dominant nitrogen-depleting bacteria in low-temperature sewage. The results showed that under the condition of water temperature at (6.5±1) ℃, the effluent denitrification effect and sludge settling rates of OPCRP-SBMBBR reactor were obviously improved. Adding fillers could improve the diversity of nitrification and denitrifying bacteria in activated sludge system. And the relative abundance, the total abundance of dominant ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB) and anaerobic denitrifying bacteria increased from 3.9%, 3.47%, and 15.87% of SBR (R1) to 5.21%, 5.26%, 23.64% of (OPCRP)-SBMBBR (R2), respectively. Heterotrophic nitrification-aerobic denitrifying bacteria, including Rhodobacteraceae, Enterobacteriaceae, and Terrimonas increased from 2.77%, 1.63%, and 2.43% of R1 to 3.3%, 3.11%, and 2.5% of R2; and unique aerobic reaction nitrifying strains of R2, Pseudomonas, Hydrogenobacter, their relative abundances were 1.17% and 0.79%, respectively. The total relative abundance of dominant aerobic denitrifying strains in R1 and R2 were 10.66% and 17.35%, respectively; the total relative abundance of dominant nitrifying strains in R1 and R2 was 7.37% and 10.47%, respectively; the total relative abundance of dominant nitrifying and denitrifying strains in R1 and R2 was 28.65% and 43.32%, respectively, which provided a good bacterial environment for biological nitrogen removal in low temperature sewage.
In view of the low biological denitrification efficiency of low-temperature sewage, the low-temperature sewage was treated by an organic polymer composite hard particle bio-carrier(OPCRP)-SBMBBR reactor. Compared with the traditional SBR reactor, two sets of reactors were analyzed by Miseq high-throughput sequencing technology. The difference in bacterial flora diversity and compositional abundance of activated sludge in the medium revealed the efficient treatment of the dominant nitrogen-depleting bacteria in low-temperature sewage. The results showed that under the condition of water temperature at (6.5±1) ℃, the effluent denitrification effect and sludge settling rates of OPCRP-SBMBBR reactor were obviously improved. Adding fillers could improve the diversity of nitrification and denitrifying bacteria in activated sludge system. And the relative abundance, the total abundance of dominant ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB) and anaerobic denitrifying bacteria increased from 3.9%, 3.47%, and 15.87% of SBR (R1) to 5.21%, 5.26%, 23.64% of (OPCRP)-SBMBBR (R2), respectively. Heterotrophic nitrification-aerobic denitrifying bacteria, including Rhodobacteraceae, Enterobacteriaceae, and Terrimonas increased from 2.77%, 1.63%, and 2.43% of R1 to 3.3%, 3.11%, and 2.5% of R2; and unique aerobic reaction nitrifying strains of R2, Pseudomonas, Hydrogenobacter, their relative abundances were 1.17% and 0.79%, respectively. The total relative abundance of dominant aerobic denitrifying strains in R1 and R2 were 10.66% and 17.35%, respectively; the total relative abundance of dominant nitrifying strains in R1 and R2 was 7.37% and 10.47%, respectively; the total relative abundance of dominant nitrifying and denitrifying strains in R1 and R2 was 28.65% and 43.32%, respectively, which provided a good bacterial environment for biological nitrogen removal in low temperature sewage.
2020, 38(10): 114-119.
doi: 10.13205/j.hjgc.202010018
Abstract:
The traditional powder phosphorus removal materials were difficult to separate from water due to its small particle size, which greatly limited its application in practical engineering. In this paper, granular phosphorus removal materials were prepared by using heat treated attapulgite clay as carrier (1~2 mm) and iron chloride (FeCl3) to active load. The optimum modification conditions, reaction time, influencing factors and phosphorus removal efficiency of the materials were studied in detail. The results showed that the maximum adsorption capacity of attapulgite clay modified by 2 mol/L iron chloride solution was 4.27 mg/g, which was about 2 times of the phosphorus fixation capacity of the original clay. The adsorption of phosphorus on iron modified attapulgite was greatly affected by pH value. The removal rate of phosphorus decreased by about 10%, as the pH value of water body increased from 4 to 11. The adsorption kinetics showed that the adsorption of phosphorus on Fe-modified attapulgite was in accordance with the quasi-second-order kinetic equation, and 84.46% of the phosphorus could be removed within 24 hours. Best effect on the regeneration of iron modified attapulgite was found using 0.2 mol/L hydrochloric acid, and then the phosphrous adsorption efficiency of the regenerated adsorbent decreased by about 40%. The above results showed that iron modified attapulgite can be used as absorbent on water bodies with low phosphrous concentration and has great application prospect.
The traditional powder phosphorus removal materials were difficult to separate from water due to its small particle size, which greatly limited its application in practical engineering. In this paper, granular phosphorus removal materials were prepared by using heat treated attapulgite clay as carrier (1~2 mm) and iron chloride (FeCl3) to active load. The optimum modification conditions, reaction time, influencing factors and phosphorus removal efficiency of the materials were studied in detail. The results showed that the maximum adsorption capacity of attapulgite clay modified by 2 mol/L iron chloride solution was 4.27 mg/g, which was about 2 times of the phosphorus fixation capacity of the original clay. The adsorption of phosphorus on iron modified attapulgite was greatly affected by pH value. The removal rate of phosphorus decreased by about 10%, as the pH value of water body increased from 4 to 11. The adsorption kinetics showed that the adsorption of phosphorus on Fe-modified attapulgite was in accordance with the quasi-second-order kinetic equation, and 84.46% of the phosphorus could be removed within 24 hours. Best effect on the regeneration of iron modified attapulgite was found using 0.2 mol/L hydrochloric acid, and then the phosphrous adsorption efficiency of the regenerated adsorbent decreased by about 40%. The above results showed that iron modified attapulgite can be used as absorbent on water bodies with low phosphrous concentration and has great application prospect.
2020, 38(10): 120-127.
doi: 10.13205/j.hjgc.202010019
Abstract:
The removal of dissolved pollutants such as nitrogen and phosphorus, heavy metals and pathogenic bacteria in bioretention systems are highly variable and even leaching out from the system. And the removal characteristic is affected by the inherent characteristics and surrounding environment of bioretention systems. Although lots of optimized researches on pollution-control capacity of bioretention systems have been carried out, and some relevant optimization measures have been proposed, these measures are mainly focused on single pollutant. No comprehensive optimization scheme of bioretention systems can meet the removal requirements of multi-target pollutants. Therefore, in this paper, removal pathways of dissolved pollutants in bioretention systems were introduced in detail as the main line, and optimization approaches for dissolved pollutants removal were comprehensively analyzed in terms of plants, fillers, configurations, and operation modes of bioretention facilities, combining with analysis on the factors influencing removal characteristics. This review is aim to establish comprehensive optimization approaches from conceptual innovations, and then it can help to achieve stable and efficient removal of multi-target pollutants in bioretention systems.
The removal of dissolved pollutants such as nitrogen and phosphorus, heavy metals and pathogenic bacteria in bioretention systems are highly variable and even leaching out from the system. And the removal characteristic is affected by the inherent characteristics and surrounding environment of bioretention systems. Although lots of optimized researches on pollution-control capacity of bioretention systems have been carried out, and some relevant optimization measures have been proposed, these measures are mainly focused on single pollutant. No comprehensive optimization scheme of bioretention systems can meet the removal requirements of multi-target pollutants. Therefore, in this paper, removal pathways of dissolved pollutants in bioretention systems were introduced in detail as the main line, and optimization approaches for dissolved pollutants removal were comprehensively analyzed in terms of plants, fillers, configurations, and operation modes of bioretention facilities, combining with analysis on the factors influencing removal characteristics. This review is aim to establish comprehensive optimization approaches from conceptual innovations, and then it can help to achieve stable and efficient removal of multi-target pollutants in bioretention systems.
2020, 38(10): 128-133,139.
doi: 10.13205/j.hjgc.202010020
Abstract:
There is certain concertarion of sulfamethoxazole(SMX) contained in wastewater from passenger train toilet, with bad biodegradability. In this paper, the sulfamethoxazole was chosen as the goal pollutants for Photo-Fenton degradation. The FeOCl powder was prepared by the thermal decomposition method. The analyzing results by XRD, SEM and XPS showed that FeOCl had a lamellar structure and a typical rectangular parallel-piped shape with good crystallinity. The SMX degradation experiments were carried out under seven different conditions and the optimal reaction condition was achieved. The concentrations of NH4+-N and H2O2 in the whole reaction system were quantitatively analyzed under the optimal condition. The inhibition effect of the co-existence of five common anions was also evaluated, which could provide theoretical and data supports for the latter pilot test.
There is certain concertarion of sulfamethoxazole(SMX) contained in wastewater from passenger train toilet, with bad biodegradability. In this paper, the sulfamethoxazole was chosen as the goal pollutants for Photo-Fenton degradation. The FeOCl powder was prepared by the thermal decomposition method. The analyzing results by XRD, SEM and XPS showed that FeOCl had a lamellar structure and a typical rectangular parallel-piped shape with good crystallinity. The SMX degradation experiments were carried out under seven different conditions and the optimal reaction condition was achieved. The concentrations of NH4+-N and H2O2 in the whole reaction system were quantitatively analyzed under the optimal condition. The inhibition effect of the co-existence of five common anions was also evaluated, which could provide theoretical and data supports for the latter pilot test.
2020, 38(10): 134-139.
doi: 10.13205/j.hjgc.202010021
Abstract:
The hydrodynamics in a three-phase air-lift internal-loop reactor were studied in terms of gas holdup, liquid circulation velocity and residence time distribution. The results showed that gas holdup was increased with superficial gas velocity and solid holdup. The solid holdup played an important role in gas holdup at lower superficial gas velocity, whereas the solid holdup had a little effect on gas holdup at higher superficial gas velocity. On the basis of lots of experimental data, the experienced correlation for predicting gas holdup was obtained. The predictable values of gas holdup were well fitted with its experimental values. A mathematical model for predicting liquid circulation velocity was proposed in terms of the balance between driving and resistance forces. The curve of residence time distribution function was gained by using pulse chasing method, and it was known that the reactor had approached completely mixing reactor in terms of computing mean of residence time, dimension and dimensionless variance of residence time distribution and so on.
The hydrodynamics in a three-phase air-lift internal-loop reactor were studied in terms of gas holdup, liquid circulation velocity and residence time distribution. The results showed that gas holdup was increased with superficial gas velocity and solid holdup. The solid holdup played an important role in gas holdup at lower superficial gas velocity, whereas the solid holdup had a little effect on gas holdup at higher superficial gas velocity. On the basis of lots of experimental data, the experienced correlation for predicting gas holdup was obtained. The predictable values of gas holdup were well fitted with its experimental values. A mathematical model for predicting liquid circulation velocity was proposed in terms of the balance between driving and resistance forces. The curve of residence time distribution function was gained by using pulse chasing method, and it was known that the reactor had approached completely mixing reactor in terms of computing mean of residence time, dimension and dimensionless variance of residence time distribution and so on.
2020, 38(10): 140-145.
doi: 10.13205/j.hjgc.202010022
Abstract:
Persistent organic pollutants (POPs) have the properties of persistent biological accumulation, semi-volatilization and long-distance migration, widely locate in soil, wastewater and sludge. POPs pollution in China is increasingly serious. Because of the advantages of supercritical water remediation technology, such as rapid, efficient and non-toxic, it has a good application prospect in the field of POPs remediation. Based on supercritical water characteristic and supercritical water remediation technology globally, the paper systematically analyzed the research status of supercritical water remediation and the merit/demerit and applicability of the technology. Then we put forward the key technology and equipment system of supercritical water remediation. The research results ccould provide reference for the development of supercritical water remediation technology.
Persistent organic pollutants (POPs) have the properties of persistent biological accumulation, semi-volatilization and long-distance migration, widely locate in soil, wastewater and sludge. POPs pollution in China is increasingly serious. Because of the advantages of supercritical water remediation technology, such as rapid, efficient and non-toxic, it has a good application prospect in the field of POPs remediation. Based on supercritical water characteristic and supercritical water remediation technology globally, the paper systematically analyzed the research status of supercritical water remediation and the merit/demerit and applicability of the technology. Then we put forward the key technology and equipment system of supercritical water remediation. The research results ccould provide reference for the development of supercritical water remediation technology.
2020, 38(10): 146-150,155.
doi: 10.13205/j.hjgc.202010023
Abstract:
Through the investigation of 27 auto repair enterprises in Beijing, two typical auto repair enterprises were selected to collect and analyze using the method of air bag sampling-GC-MS-FID, in order to quantitatively analyze the emission characteristics of VOCs, and calculate the ozone generating potential (OFP). The result showed that the emission characteristics of steam repair enterprises using different paints were different. The emission concentration of non-methane total hydrocarbons in water-based paint enterprises was between 0.62~36.49 mg/m3, and the discharge concentration range of oil paint enterprises was 0~100.39 mg/m3. The VOCs emitted by water-based paints were mainly alkanes, accounting for 57.16% of total VOCs, and propane (39.65%) and toluene (11.41%) were primary pollutants. Halogenated hydrocarbon (55.51%) was the main VOCs emission species of oil paint enterprises, and its main components were 1,2-dichloropropane and 1,2-dichloroethane. The OFP of water-based paint enterprises was 144.78 mg/m3, and the oil-forming paint company’s OFP was 664.43 mg/m3. Most of the atmospheric reactive species were aromatic hydrocarbons. The contribution rates of aromatic hydrocarbons to OFP were 52.18% and 88.44%, respectively.
Through the investigation of 27 auto repair enterprises in Beijing, two typical auto repair enterprises were selected to collect and analyze using the method of air bag sampling-GC-MS-FID, in order to quantitatively analyze the emission characteristics of VOCs, and calculate the ozone generating potential (OFP). The result showed that the emission characteristics of steam repair enterprises using different paints were different. The emission concentration of non-methane total hydrocarbons in water-based paint enterprises was between 0.62~36.49 mg/m3, and the discharge concentration range of oil paint enterprises was 0~100.39 mg/m3. The VOCs emitted by water-based paints were mainly alkanes, accounting for 57.16% of total VOCs, and propane (39.65%) and toluene (11.41%) were primary pollutants. Halogenated hydrocarbon (55.51%) was the main VOCs emission species of oil paint enterprises, and its main components were 1,2-dichloropropane and 1,2-dichloroethane. The OFP of water-based paint enterprises was 144.78 mg/m3, and the oil-forming paint company’s OFP was 664.43 mg/m3. Most of the atmospheric reactive species were aromatic hydrocarbons. The contribution rates of aromatic hydrocarbons to OFP were 52.18% and 88.44%, respectively.
2020, 38(10): 151-155.
doi: 10.13205/j.hjgc.202010024
Abstract:
In order to optimize the reasonable spray gun layout of circulating fluidized bed semi-dry desulfurization and denitrification reactor, the circulating fluidized bed simultaneous desulfurization and denitrification tower of a thermal power plant was taken as the original object in this paper, and the high pressure water spray gun layout in the reactor was simulated. Through simulation and comparison of results, a more suitable spray gun layout was obtained. The optimum setting of spray guns was 4 with circular arrangement. The advisable distance of the spray gun inserted into the tower was 0.5~0.7 m. The maximum droplet size of the spray was less than 150 μm, which was conducive to the uniform distribution within the reactor and the complete evaporation of the droplet, achieving smooth and stable running of circulating fluidized bed semi-dry reactor,as well as high efficiency desulfurization and denitrification.
In order to optimize the reasonable spray gun layout of circulating fluidized bed semi-dry desulfurization and denitrification reactor, the circulating fluidized bed simultaneous desulfurization and denitrification tower of a thermal power plant was taken as the original object in this paper, and the high pressure water spray gun layout in the reactor was simulated. Through simulation and comparison of results, a more suitable spray gun layout was obtained. The optimum setting of spray guns was 4 with circular arrangement. The advisable distance of the spray gun inserted into the tower was 0.5~0.7 m. The maximum droplet size of the spray was less than 150 μm, which was conducive to the uniform distribution within the reactor and the complete evaporation of the droplet, achieving smooth and stable running of circulating fluidized bed semi-dry reactor,as well as high efficiency desulfurization and denitrification.
2020, 38(10): 156-161,46.
doi: 10.13205/j.hjgc.202010025
Abstract:
Low concentration coal-bed gas resources are rich in China, but the utilization rate is low, and most of it is directly emitted into the environment, not only caused the waste of resources, also increased atmospheric greenhouse effect. Therefore, the study on enrichment and separation of low-concentration coal-bed gas by pressure-swing adsorption (PSA) technology has the dual function of energy saving and environmental protection. In this paper, the dual-tower vacuum PSA device was used, and the adsorbent in the experiment was activated carbon and carbon molecular sieve mixing adsorbent. The influence of adsorption pressure, half-period, adsorption tower height diameter ratio and mixed adsorbent ratio on the separation effect of CH4 were investigated, and the optimal process conditions were determined as follows:180 kPa, 90 s, 7 and 2, namely. The results could provide technical support for the resource utilization of low concentration coal-bed gas.
Low concentration coal-bed gas resources are rich in China, but the utilization rate is low, and most of it is directly emitted into the environment, not only caused the waste of resources, also increased atmospheric greenhouse effect. Therefore, the study on enrichment and separation of low-concentration coal-bed gas by pressure-swing adsorption (PSA) technology has the dual function of energy saving and environmental protection. In this paper, the dual-tower vacuum PSA device was used, and the adsorbent in the experiment was activated carbon and carbon molecular sieve mixing adsorbent. The influence of adsorption pressure, half-period, adsorption tower height diameter ratio and mixed adsorbent ratio on the separation effect of CH4 were investigated, and the optimal process conditions were determined as follows:180 kPa, 90 s, 7 and 2, namely. The results could provide technical support for the resource utilization of low concentration coal-bed gas.
2020, 38(10): 162-168,127.
doi: 10.13205/j.hjgc.202010026
Abstract:
Fine particles are inflicting great harm on human health due to their small particle size and absorption of hazardous components on them. But the conventional dust remover cannot remove it effectively. Sound wave can effectively increase the collision and agglomeration of particles and increase the particle size of PM2.5, which is a promising dust removal pretreatment technology. The acoustic frequency, sound pressure level (SPL), initial concentration and residence time are the main factors for the acoustic agglomeration efficiency. It was found that the effect was better under the action of low frequency sound wave, but the best agglomeration efficiency was only 43.07% under the action of pure acoustic agglomeration. The dust morphology before and after the experiment was compared by scanning electron microscope, and the agglomeration effect of acoustic wave on aerosol particles was verified. Then this study used spray as an auxiliary means to further improve the agglomeration efficiency and reduce the energy consumption of acoustic agglomeration. The effects of frequency, SPL and spray volume on the agglomeration efficiency were investigated. The agglomeration efficiency increased to 66.48% after spray. It showed that spray combined with acoustic agglomeration was an effective dust removal pretreatment technology.
Fine particles are inflicting great harm on human health due to their small particle size and absorption of hazardous components on them. But the conventional dust remover cannot remove it effectively. Sound wave can effectively increase the collision and agglomeration of particles and increase the particle size of PM2.5, which is a promising dust removal pretreatment technology. The acoustic frequency, sound pressure level (SPL), initial concentration and residence time are the main factors for the acoustic agglomeration efficiency. It was found that the effect was better under the action of low frequency sound wave, but the best agglomeration efficiency was only 43.07% under the action of pure acoustic agglomeration. The dust morphology before and after the experiment was compared by scanning electron microscope, and the agglomeration effect of acoustic wave on aerosol particles was verified. Then this study used spray as an auxiliary means to further improve the agglomeration efficiency and reduce the energy consumption of acoustic agglomeration. The effects of frequency, SPL and spray volume on the agglomeration efficiency were investigated. The agglomeration efficiency increased to 66.48% after spray. It showed that spray combined with acoustic agglomeration was an effective dust removal pretreatment technology.
2020, 38(10): 169-176.
doi: 10.13205/j.hjgc.202010027
Abstract:
In order to investigate the effects of steel slag on pyrolysis of oil sludge, the collaborative disposal of oil sludge and steel slag was proposed. We took typical steel slag and oil tank bottom sludge in Beijing-Tianjin-Hebei region as the experimental samples. The effects of the pyrolysis temperature, heating rate, residence time and addition amount of steel slag on pyrolysis products of oil tank bottom sludge in single factor experiments and response surface experiment were conducted using a fixed-bed reactor. In addition, the composition of pyrolysis gases and tar were investigated using GC, GC-MS, SEM and FTIR, respectively. The results showed that with the increase of the pyrolysis final temperature, heating rate and residence time, the pyrolysis tar yield increased first and then decreased. And the pyrolysis tar yield of oil sludge reached the maximum value as the temperature, heating rate and residence time reached 550 ℃, 40 ℃/min and 30min, respectively. Adding steel slag was conducive to increase the weightlessness rate of oil sludge, and the pyrolysis kinetics showed that the apparent activation energy were 8.32 kJ/mol and 7.43 kJ/mol, as the oil sludge pyrolysis (OS) and oil sludge pyrolysis with steel slag(OSSS), respectively. The addition of steel slag promoted the yield of pyrolysis tar and gas, and reduced char yield. The gas composition analysis indicated that steel slag could act as a catalyst in improving the H2 and CH4 content and reducing CO2 content during the pyrolysis process of oil sludge. The addition of steel slag significantly increased the content of short alkanes and increased the C5~C10 fraction by improving the decomposition of the C15~C20 fraction. It was concluded that the integration of oil sludge pyrolysis with steel slag and the recovery of steel slag from the solid pyrolysis products of oil sludge containing steel slag could be feasible.
In order to investigate the effects of steel slag on pyrolysis of oil sludge, the collaborative disposal of oil sludge and steel slag was proposed. We took typical steel slag and oil tank bottom sludge in Beijing-Tianjin-Hebei region as the experimental samples. The effects of the pyrolysis temperature, heating rate, residence time and addition amount of steel slag on pyrolysis products of oil tank bottom sludge in single factor experiments and response surface experiment were conducted using a fixed-bed reactor. In addition, the composition of pyrolysis gases and tar were investigated using GC, GC-MS, SEM and FTIR, respectively. The results showed that with the increase of the pyrolysis final temperature, heating rate and residence time, the pyrolysis tar yield increased first and then decreased. And the pyrolysis tar yield of oil sludge reached the maximum value as the temperature, heating rate and residence time reached 550 ℃, 40 ℃/min and 30min, respectively. Adding steel slag was conducive to increase the weightlessness rate of oil sludge, and the pyrolysis kinetics showed that the apparent activation energy were 8.32 kJ/mol and 7.43 kJ/mol, as the oil sludge pyrolysis (OS) and oil sludge pyrolysis with steel slag(OSSS), respectively. The addition of steel slag promoted the yield of pyrolysis tar and gas, and reduced char yield. The gas composition analysis indicated that steel slag could act as a catalyst in improving the H2 and CH4 content and reducing CO2 content during the pyrolysis process of oil sludge. The addition of steel slag significantly increased the content of short alkanes and increased the C5~C10 fraction by improving the decomposition of the C15~C20 fraction. It was concluded that the integration of oil sludge pyrolysis with steel slag and the recovery of steel slag from the solid pyrolysis products of oil sludge containing steel slag could be feasible.
2020, 38(10): 177-182,52.
doi: 10.13205/j.hjgc.202010028
Abstract:
In order to realize the resource utilization of solid waste material in solidification of saline soil,calcium carbide slag, fly ash and slag were selected to form a salinized soil curing agent,and the 28 d compressive strength of solidified saline soil was studied. Projective pursuit regression (PPR) was used to analyze the high-dimensional test data, and a 28 d PPR calculation model was established to verify the accuracy and stability of the model, Finally, the model was used for simulation calculation to explore the relationship between the influence factors and the compressive strength of solidified saline soil. The results showed that the PPR model had high accuracy and good stability, and the weight coefficients of each influence factor to compressive strength were ranked as the sequence of content of volcanic ash material>proportion of slag>content of sulfate>content of calcium carbide slag; the relationship between the influence factors and the compressive strength of solidified saline soil was described quantitatively; and the PPR model had deeply explored the internal structure of the high dimensional compressive strength data of cured saline soil, which provided references for the study of mechanical properties of cured saline soil with solid waste materials.
In order to realize the resource utilization of solid waste material in solidification of saline soil,calcium carbide slag, fly ash and slag were selected to form a salinized soil curing agent,and the 28 d compressive strength of solidified saline soil was studied. Projective pursuit regression (PPR) was used to analyze the high-dimensional test data, and a 28 d PPR calculation model was established to verify the accuracy and stability of the model, Finally, the model was used for simulation calculation to explore the relationship between the influence factors and the compressive strength of solidified saline soil. The results showed that the PPR model had high accuracy and good stability, and the weight coefficients of each influence factor to compressive strength were ranked as the sequence of content of volcanic ash material>proportion of slag>content of sulfate>content of calcium carbide slag; the relationship between the influence factors and the compressive strength of solidified saline soil was described quantitatively; and the PPR model had deeply explored the internal structure of the high dimensional compressive strength data of cured saline soil, which provided references for the study of mechanical properties of cured saline soil with solid waste materials.
TREATMENT OF DOMESTIC WASTE BY ULTRA-HIGH TEMPERATURE SPONTANEOUS HEATING AEROBIC COMPOSTING PROCESS
2020, 38(10): 183-189.
doi: 10.13205/j.hjgc.202010029
Abstract:
Ultra-high temperature spontaneous heating has been applied to aerobic composting of excess sludge. However, the effect of this technology on aerobic composting of domestic waste was not clear. In addition, the effect of nitrogen fixing agent calcium superphosphate (CS) on ultra-high temperature spontaneous heating aerobic composting for domestic waste treatment was not clear, either. In this study, the blank group (R1) and the composting system with CS (R2) were established. The changes of temperature, oxygen content, moisture content, greenhouse gas release, soluble COD and maturity index, in the process of super-high temperature spontaneous heating of domestic waste under the influence of CS were investigated. The effects of CS on the microbial community characteristics of domestic waste composting were analyzed. The results showed that the highest temperature of R2 was 80.3℃, higher than that of blank group, and the lowest oxygen content and water content were lower than that of R1. The maximum releasing rates of methane and N2O in R2 were 0.09 g/(kg·d) and 1.3 g/(kg·d), respectively, significantly lower than those in R1. The presence of CS was beneficial to nitrogen conservation in MSW composting. In addition, the maximum soluble COD content in R2 was 42.3 mg/g, slightly higher than that in R1. CS was beneficial to the release of organic matter in the reactor. The relative abundance of Saccharomonospor and Planifilum in R2 was 25.6% and 10.3% respectively, and the maturity of the stack was also higher.
Ultra-high temperature spontaneous heating has been applied to aerobic composting of excess sludge. However, the effect of this technology on aerobic composting of domestic waste was not clear. In addition, the effect of nitrogen fixing agent calcium superphosphate (CS) on ultra-high temperature spontaneous heating aerobic composting for domestic waste treatment was not clear, either. In this study, the blank group (R1) and the composting system with CS (R2) were established. The changes of temperature, oxygen content, moisture content, greenhouse gas release, soluble COD and maturity index, in the process of super-high temperature spontaneous heating of domestic waste under the influence of CS were investigated. The effects of CS on the microbial community characteristics of domestic waste composting were analyzed. The results showed that the highest temperature of R2 was 80.3℃, higher than that of blank group, and the lowest oxygen content and water content were lower than that of R1. The maximum releasing rates of methane and N2O in R2 were 0.09 g/(kg·d) and 1.3 g/(kg·d), respectively, significantly lower than those in R1. The presence of CS was beneficial to nitrogen conservation in MSW composting. In addition, the maximum soluble COD content in R2 was 42.3 mg/g, slightly higher than that in R1. CS was beneficial to the release of organic matter in the reactor. The relative abundance of Saccharomonospor and Planifilum in R2 was 25.6% and 10.3% respectively, and the maturity of the stack was also higher.
2020, 38(10): 190-195,215.
doi: 10.13205/j.hjgc.202010030
Abstract:
In this paper, the effects of the amount of chelating agent, the addition of water and the mixing time on the leaching concentration of various heavy metals from waste incineration fly ash during the stabilization process were studied. And the leaching behaviors of heavy metals in different conditions including natural environment, with ultraviolet light and at 35 ℃ was investigated, to compare the chelation properties of macro molecular DTC and small molecule SDD. The results showed that when the dosage of chelating agent reached 3%, the leaching concentration of six heavy metals commonly found in fly ash was lower than the specified limit given in GB 16889—2008; for Pb, Zn and Cd, increasing the water content during chelation could reduce the concentration of heavy metals in the leachate; when the mixing time exceeded two minutes, the leaching of heavy metals from the fly ash was basically stable. The leaching concentration of heavy metals in the chelated fly ash under different conditions all met the landfill admission control standard, and it was found that DTC had better chelation effect, compared with SDD.
In this paper, the effects of the amount of chelating agent, the addition of water and the mixing time on the leaching concentration of various heavy metals from waste incineration fly ash during the stabilization process were studied. And the leaching behaviors of heavy metals in different conditions including natural environment, with ultraviolet light and at 35 ℃ was investigated, to compare the chelation properties of macro molecular DTC and small molecule SDD. The results showed that when the dosage of chelating agent reached 3%, the leaching concentration of six heavy metals commonly found in fly ash was lower than the specified limit given in GB 16889—2008; for Pb, Zn and Cd, increasing the water content during chelation could reduce the concentration of heavy metals in the leachate; when the mixing time exceeded two minutes, the leaching of heavy metals from the fly ash was basically stable. The leaching concentration of heavy metals in the chelated fly ash under different conditions all met the landfill admission control standard, and it was found that DTC had better chelation effect, compared with SDD.
2020, 38(10): 196-201.
doi: 10.13205/j.hjgc.202010031
Abstract:
Three typical dewatered sludge were taken as research objects, and mixed with soil as the cultivation substrate for potted experiment of ryegrass, in order to understand the effect of dehydration on subsequent land use of sludge. By measuring the organic matter content, pH, bulk density, porosity and other physical and chemical properties of the composite matrix after planting, and observing the growth status of ryegrass, the influence of sludge through different dehydration processes on soil improvement was studied. Soil column leaching experiment was used to simulate 1 year’s precipitation, the environmental risk of electrolytic dewatering sludge was studied. The key research results were as follows: the dehydrated sludge by electrolysis and mechanical pressure filtration had good effect on soil water retention; the content of Cu, Cr, Cd, Pb, Ni in leachate was determined by using electrolytic dehydrated sludge as the soil conditioner after simulating 1 year’ natural precipitation, which proved electrolytic dewatered sludge pollution risk was low.
Three typical dewatered sludge were taken as research objects, and mixed with soil as the cultivation substrate for potted experiment of ryegrass, in order to understand the effect of dehydration on subsequent land use of sludge. By measuring the organic matter content, pH, bulk density, porosity and other physical and chemical properties of the composite matrix after planting, and observing the growth status of ryegrass, the influence of sludge through different dehydration processes on soil improvement was studied. Soil column leaching experiment was used to simulate 1 year’s precipitation, the environmental risk of electrolytic dewatering sludge was studied. The key research results were as follows: the dehydrated sludge by electrolysis and mechanical pressure filtration had good effect on soil water retention; the content of Cu, Cr, Cd, Pb, Ni in leachate was determined by using electrolytic dehydrated sludge as the soil conditioner after simulating 1 year’ natural precipitation, which proved electrolytic dewatered sludge pollution risk was low.
2020, 38(10): 202-206,227.
doi: 10.13205/j.hjgc.202010032
Abstract:
A field experiment was conducted in 2 hm2 Cd contaminated paddy in Pingxiang, Jiangxi province, to study the spatial heterogeneity and correlation characteristics of soil physical and chemical properties, microbes and enzyme activities. The results showed that the variation coefficient of Cd in brown rice was larger than available Cd and total Cd in soil, and the variability of late rice was higher than that of early rice, which was with moderately variability. The coefficients of variation of pH and bulk density in soil was small, and the coefficients of variation of organic matter, cation exchange capacity, available potassium, available phosphorus and alkali nitrogen were in range of 22.82%~35.60%, with moderate variability. In addition to the variability of catalase was smaller, the variation coefficient of enzyme activity, mechanical composition and microaggregate in soil was 10.54%~38.21%, which was with moderate variability. The variability of microbes in soil was strong (in range of 52.59%~84.64%), in the sequence of bacteria > actinomycetes > fungi. Correlation analysis showed that pH, sand, invertase, acid phosphatase and catalase in soil had strong negative correlation with organic matter, cation exchange capacity, clay, available phosphorus, available potassium, fungi and urease in soil. While, there was a strong positive correlation between organic matter, cation exchange capacity, cosmid, available phosphorus, available potassium, fungi and urease. Principal component analysis results indicated that pH, organic matter, bulk density, available potassium and alkali nitrogen were key factors in soil physical and chemical properties.
A field experiment was conducted in 2 hm2 Cd contaminated paddy in Pingxiang, Jiangxi province, to study the spatial heterogeneity and correlation characteristics of soil physical and chemical properties, microbes and enzyme activities. The results showed that the variation coefficient of Cd in brown rice was larger than available Cd and total Cd in soil, and the variability of late rice was higher than that of early rice, which was with moderately variability. The coefficients of variation of pH and bulk density in soil was small, and the coefficients of variation of organic matter, cation exchange capacity, available potassium, available phosphorus and alkali nitrogen were in range of 22.82%~35.60%, with moderate variability. In addition to the variability of catalase was smaller, the variation coefficient of enzyme activity, mechanical composition and microaggregate in soil was 10.54%~38.21%, which was with moderate variability. The variability of microbes in soil was strong (in range of 52.59%~84.64%), in the sequence of bacteria > actinomycetes > fungi. Correlation analysis showed that pH, sand, invertase, acid phosphatase and catalase in soil had strong negative correlation with organic matter, cation exchange capacity, clay, available phosphorus, available potassium, fungi and urease in soil. While, there was a strong positive correlation between organic matter, cation exchange capacity, cosmid, available phosphorus, available potassium, fungi and urease. Principal component analysis results indicated that pH, organic matter, bulk density, available potassium and alkali nitrogen were key factors in soil physical and chemical properties.
2020, 38(10): 207-215.
doi: 10.13205/j.hjgc.202010033
Abstract:
The role of surfactant in soil and groundwater remediation depends on its transport behaviors in subsurface porous media. Therefore, an in-depth study about the transport behavior of surfactants is of great importance for effective application of the surfactants in the remediation. This paper reviewed the research progress on surfactant transport in subsurface porous media, including the main processes and theoretical models of the transport and factors affecting transport processes. In addition, the existing deficiencies and the future directions for the studies on the transport of surfactants in subsurface porous media were proposed to provide relevant theoretical guidance for the soil and groundwater remediation process.
The role of surfactant in soil and groundwater remediation depends on its transport behaviors in subsurface porous media. Therefore, an in-depth study about the transport behavior of surfactants is of great importance for effective application of the surfactants in the remediation. This paper reviewed the research progress on surfactant transport in subsurface porous media, including the main processes and theoretical models of the transport and factors affecting transport processes. In addition, the existing deficiencies and the future directions for the studies on the transport of surfactants in subsurface porous media were proposed to provide relevant theoretical guidance for the soil and groundwater remediation process.
2020, 38(10): 216-221.
doi: 10.13205/j.hjgc.202010034
Abstract:
The biochars were prepared by pyrolysis using municipal sludge as the raw material and nano-zero-valent iron (nZVI) as the additive. The effect of nZVI addition, pyrolysis temperature and heating rate on speciation distribution and ecological risk of Zn, Cu and Pb in biochars was investigated. The results showed that the higher nZVI addition, higher pyrolysis temperature and lower heating rate could increase the contents of Zn, Cu and Pb in the steady state (BCR method). The higher nZVI addition could promote the conversion of Zn, Cu and Pb to the oxidizable state, while the higher pyrolysis temperature and lower heating rate were favorable for the formation of residual Zn, Cu and Pb. The optimized nZVI addition, pyrolysis temperature and heating rate were 2000 mg/kg, 800 ℃ and 4 ℃/min, respectively. In addition, when the addition amount of nZVI was 800 mg/kg, the pyrolysis temperature was 800 ℃ and the heating rate was 2 ℃/min, which was conducive to reduce the ecological risk of Zn, Cu and Pb. The approximate ecological risk levels of Zn, Cu and Pb were low risk, low risk and no risk, respectively. Compared with Cu and Pb, the ecological risk of Zn was higher. If the RI value was used as the evaluation index, the optimized preparation process of nZVI/sludge-based biochar was as follow: nZVI dosage of 200 mg/kg, pyrolysis temperature of 800 ℃, heating rate of 5 ℃/min.
The biochars were prepared by pyrolysis using municipal sludge as the raw material and nano-zero-valent iron (nZVI) as the additive. The effect of nZVI addition, pyrolysis temperature and heating rate on speciation distribution and ecological risk of Zn, Cu and Pb in biochars was investigated. The results showed that the higher nZVI addition, higher pyrolysis temperature and lower heating rate could increase the contents of Zn, Cu and Pb in the steady state (BCR method). The higher nZVI addition could promote the conversion of Zn, Cu and Pb to the oxidizable state, while the higher pyrolysis temperature and lower heating rate were favorable for the formation of residual Zn, Cu and Pb. The optimized nZVI addition, pyrolysis temperature and heating rate were 2000 mg/kg, 800 ℃ and 4 ℃/min, respectively. In addition, when the addition amount of nZVI was 800 mg/kg, the pyrolysis temperature was 800 ℃ and the heating rate was 2 ℃/min, which was conducive to reduce the ecological risk of Zn, Cu and Pb. The approximate ecological risk levels of Zn, Cu and Pb were low risk, low risk and no risk, respectively. Compared with Cu and Pb, the ecological risk of Zn was higher. If the RI value was used as the evaluation index, the optimized preparation process of nZVI/sludge-based biochar was as follow: nZVI dosage of 200 mg/kg, pyrolysis temperature of 800 ℃, heating rate of 5 ℃/min.
2020, 38(10): 222-227.
doi: 10.13205/j.hjgc.202010035
Abstract:
In this study, red soil, purple soil, black soil and yellow soil were used to study the stabilization effect of modified nano-titanium dioxide on arsenic in soil. The modified nano titanium dioxide was prepared by sol-gel process. The active carbon supported nano titanium dioxide (ACT) and iron modified activated carbon supported titanium dioxide (ACTI) were prepared by sol gel method. The nano size titanium dioxide (T-100) and activated carbon (AC) with a diameter of 100nm were used as the control materials. Modified nano-titanium dioxide was added to the tested soil according to different mass ratios. After 14 days of stabilization, the stabilization effect of modified nano-titanium dioxide on arsenic in different types of soil was studied by simple bioavailability extraction test SBET. The results showed that the arsenic fixation ability of the four types of tested soils was in the sequence of red soil>black soil>yellow soil>purple soil. ACTI and ACT were superior to the control materials T-100 and AC in arsenic stabilization in four types of soils. With 2% addition of ACTI and ACT, the stabilization rates of arsenic in four types of soils were higher than 60%. Therefore, ACTI and ACT can be used as stabilizers for arsenic-contaminated soil remediation.
In this study, red soil, purple soil, black soil and yellow soil were used to study the stabilization effect of modified nano-titanium dioxide on arsenic in soil. The modified nano titanium dioxide was prepared by sol-gel process. The active carbon supported nano titanium dioxide (ACT) and iron modified activated carbon supported titanium dioxide (ACTI) were prepared by sol gel method. The nano size titanium dioxide (T-100) and activated carbon (AC) with a diameter of 100nm were used as the control materials. Modified nano-titanium dioxide was added to the tested soil according to different mass ratios. After 14 days of stabilization, the stabilization effect of modified nano-titanium dioxide on arsenic in different types of soil was studied by simple bioavailability extraction test SBET. The results showed that the arsenic fixation ability of the four types of tested soils was in the sequence of red soil>black soil>yellow soil>purple soil. ACTI and ACT were superior to the control materials T-100 and AC in arsenic stabilization in four types of soils. With 2% addition of ACTI and ACT, the stabilization rates of arsenic in four types of soils were higher than 60%. Therefore, ACTI and ACT can be used as stabilizers for arsenic-contaminated soil remediation.
2020, 38(10): 228-233.
doi: 10.13205/j.hjgc.202010036
Abstract:
In this paper, the effect of electrode-orientated electrokinetic enhancement on phytoremediation on arsenic contaminated soil was investigated based on Capsicum annuum L. The results showed that soil pH decreased in the control group and increased in the experimental group. The soil arsenic concentration in the control group decreased from (524.1±5.6) mg/kg to (500.5±8.3) mg/kg, and the soil arsenic concentration in different areas of the experimental group was (179.8±10.6), (674.9±5.43), (512.8±7.3) mg/kg, respectively. Compared with the control group, the amount of arsenic absorbed by plants in the experimental group increased by -18.1%, 282.8% and 170.3%, respectively. The ratio of arsenic concentration in soil and rhizosphere in control group and experimental group 1, 2 and 3 was 2.62, 0.64, 1.48 and 1.26, respectively. The electric field increased the arsenic concentration near plant roots. In the control group and the experimental group, the residue arsenic content of the fifth day was 55.64%, 34.99%, 39.06% and 0%. In the soil of experimental group, and near the cathode on the 5th and 10th day of the control group, the proportions of Fe/Al oxide binding state and residue arsenic in the crystallized water were 67.45%, 0% and 8.88%, respectively. It reflected the activation effect of electric field on soil heavy metal forms. The power consumption of the experimental group for 10 days repairing was RMB 79.5/m3, with considerable economical advantages.
In this paper, the effect of electrode-orientated electrokinetic enhancement on phytoremediation on arsenic contaminated soil was investigated based on Capsicum annuum L. The results showed that soil pH decreased in the control group and increased in the experimental group. The soil arsenic concentration in the control group decreased from (524.1±5.6) mg/kg to (500.5±8.3) mg/kg, and the soil arsenic concentration in different areas of the experimental group was (179.8±10.6), (674.9±5.43), (512.8±7.3) mg/kg, respectively. Compared with the control group, the amount of arsenic absorbed by plants in the experimental group increased by -18.1%, 282.8% and 170.3%, respectively. The ratio of arsenic concentration in soil and rhizosphere in control group and experimental group 1, 2 and 3 was 2.62, 0.64, 1.48 and 1.26, respectively. The electric field increased the arsenic concentration near plant roots. In the control group and the experimental group, the residue arsenic content of the fifth day was 55.64%, 34.99%, 39.06% and 0%. In the soil of experimental group, and near the cathode on the 5th and 10th day of the control group, the proportions of Fe/Al oxide binding state and residue arsenic in the crystallized water were 67.45%, 0% and 8.88%, respectively. It reflected the activation effect of electric field on soil heavy metal forms. The power consumption of the experimental group for 10 days repairing was RMB 79.5/m3, with considerable economical advantages.
