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2023 Vol. 41, No. 12
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2023, 41(12): 1-10.
doi: 10.13205/j.hjgc.202312001
Abstract:
To remove endocrine disruptors in water efficiently, perovskite LaBO3 (B=Fe, Cr, Co) catalyst was synthesized by sol-gel method to catalyze the degradation of bisphenol A (BPA) in water by peracetic acid (PAA). The morphology and microstructure of the catalyst were characterized using TG-DSC, SEM, TEM, XRD, etc. The effect of catalytic PAA removal of BPA under different conditions was studied, and the catalytic PAA reaction mechanism was proposed. The results indicated that LaBO3 (B=Fe, Cr, Co) was an irregular sphere with varying sizes, smooth surfaces, and aggregation. The specific surface area of LaCoO3 was 11.89 m2/g. BPA degradation could reach 85% in the LaCoO3/PAA system, significantly higher than that of LaCrO3/PAA (14%) and LaFeO3/PAA (14%) systems. In addition, the LaCoO3/PAA system also exhibited good degradation efficiency on other pollutants (orange I, sulfamethoxazole, 4-chlorophenol), and had strong anti-interference ability with common inorganic anions and humic acids in water, making LaCoO3 an environmentally friendly catalyst with promising development prospects. The quenching experiment combined with electron spin resonance spectroscopy revealed that organic radicals were the main active species causing BPA degradation in the LaCoO3/PAA system. The electron transfer pathway was the secondary oxidation pathway for the catalytic degradation of BPA in the LaCoO3/PAA system. In addition, the oxidation-reduction reaction between ≡CoⅢ/≡CoⅡ and PAA ensured the continuous generation of radicals and high degradation efficiency. This work can provide new insight into the treatment of endocrine disruptors in water pollution.
To remove endocrine disruptors in water efficiently, perovskite LaBO3 (B=Fe, Cr, Co) catalyst was synthesized by sol-gel method to catalyze the degradation of bisphenol A (BPA) in water by peracetic acid (PAA). The morphology and microstructure of the catalyst were characterized using TG-DSC, SEM, TEM, XRD, etc. The effect of catalytic PAA removal of BPA under different conditions was studied, and the catalytic PAA reaction mechanism was proposed. The results indicated that LaBO3 (B=Fe, Cr, Co) was an irregular sphere with varying sizes, smooth surfaces, and aggregation. The specific surface area of LaCoO3 was 11.89 m2/g. BPA degradation could reach 85% in the LaCoO3/PAA system, significantly higher than that of LaCrO3/PAA (14%) and LaFeO3/PAA (14%) systems. In addition, the LaCoO3/PAA system also exhibited good degradation efficiency on other pollutants (orange I, sulfamethoxazole, 4-chlorophenol), and had strong anti-interference ability with common inorganic anions and humic acids in water, making LaCoO3 an environmentally friendly catalyst with promising development prospects. The quenching experiment combined with electron spin resonance spectroscopy revealed that organic radicals were the main active species causing BPA degradation in the LaCoO3/PAA system. The electron transfer pathway was the secondary oxidation pathway for the catalytic degradation of BPA in the LaCoO3/PAA system. In addition, the oxidation-reduction reaction between ≡CoⅢ/≡CoⅡ and PAA ensured the continuous generation of radicals and high degradation efficiency. This work can provide new insight into the treatment of endocrine disruptors in water pollution.
2023, 41(12): 11-20,75.
doi: 10.13205/j.hjgc.202312002
Abstract:
Under the pressure of the increasing urban non-point source pollution load in China, it is crucial to optimize urban non-point source pollution control technologies to ensure the safety of urban water systems. In this study, a bibliometric analysis of global relevant research on urban non-point source pollution control technologies in the last 20 years was conducted. The optimization strategies for urban non-point source pollution control under different underlying surface conditions, drainage systems, and rainfall characteristics were summarized. This included the optimization schemes of the "green-gray-blue" combination, "source-network-plant-river", and "source drainage-small drainage-large drainage". These schemes aim to maximize the effectiveness of the comprehensive non-point source pollution prevention system that encompasses the entire process from source to end. The study provides insights for the control of urban non-point source pollution.
Under the pressure of the increasing urban non-point source pollution load in China, it is crucial to optimize urban non-point source pollution control technologies to ensure the safety of urban water systems. In this study, a bibliometric analysis of global relevant research on urban non-point source pollution control technologies in the last 20 years was conducted. The optimization strategies for urban non-point source pollution control under different underlying surface conditions, drainage systems, and rainfall characteristics were summarized. This included the optimization schemes of the "green-gray-blue" combination, "source-network-plant-river", and "source drainage-small drainage-large drainage". These schemes aim to maximize the effectiveness of the comprehensive non-point source pollution prevention system that encompasses the entire process from source to end. The study provides insights for the control of urban non-point source pollution.
2023, 41(12): 21-31.
doi: 10.13205/j.hjgc.202312003
Abstract:
In the process of water environment management in China, non-point source pollution caused by rainfall runoff has caused serious environmental pollution problems such as black and odorous rivers, which have received extensive attention. Non-point source pollution is mainly divided into agricultural non-point source pollution and urban non-point source pollution, according to different underlying surfaces. Based on the global literature on urban runoff pollution, this paper summarizes the characteristics of urban runoff pollution, pollution load model, and treatment technology and effect. In China, SS is the main pollutant in urban runoff, reaching more than 200 mg/L, and COD, TP, and TN concentrations are also far higher than the emission standards. At the same time, microplastics and heavy metals were also detected in the runoff. The most widely used surface source load models in China are compared and analyzed, and their advantages, disadvantages, and application scenarios are given. The technology and effectiveness of non-point source pollution control in recent years are collected, and its limitations are summarized. Future research should be concentrated on GIS coupling, technology combination optimization, plant network river dispatching, and whole process governance.
In the process of water environment management in China, non-point source pollution caused by rainfall runoff has caused serious environmental pollution problems such as black and odorous rivers, which have received extensive attention. Non-point source pollution is mainly divided into agricultural non-point source pollution and urban non-point source pollution, according to different underlying surfaces. Based on the global literature on urban runoff pollution, this paper summarizes the characteristics of urban runoff pollution, pollution load model, and treatment technology and effect. In China, SS is the main pollutant in urban runoff, reaching more than 200 mg/L, and COD, TP, and TN concentrations are also far higher than the emission standards. At the same time, microplastics and heavy metals were also detected in the runoff. The most widely used surface source load models in China are compared and analyzed, and their advantages, disadvantages, and application scenarios are given. The technology and effectiveness of non-point source pollution control in recent years are collected, and its limitations are summarized. Future research should be concentrated on GIS coupling, technology combination optimization, plant network river dispatching, and whole process governance.
2023, 41(12): 32-47.
doi: 10.13205/j.hjgc.202312004
Abstract:
During the rainfall process, pipeline rainwater overflow occurs when the flow rate exceeds its carrying capacity, which pollutes the urban water body, so it is of great significance to study the pollution control of urban combined sewer overflows (CSOs) for the prevention and control of urban water pollution. In this paper, global literature of CSOs pollution are analyzed by bibliographic method. Results showed the characteristics and control measures of CSOs pollution were the main research hotspots. This paper also analyzes the causes, water quality and quantity characteristics, and variation laws of CSOs pollution, and then discusses various measures from two aspects: reducing the frequency of overflow pollution and controlling after overflow pollution. Finally, this paper summarized and prospected the development of CSOs pollution control in China.
During the rainfall process, pipeline rainwater overflow occurs when the flow rate exceeds its carrying capacity, which pollutes the urban water body, so it is of great significance to study the pollution control of urban combined sewer overflows (CSOs) for the prevention and control of urban water pollution. In this paper, global literature of CSOs pollution are analyzed by bibliographic method. Results showed the characteristics and control measures of CSOs pollution were the main research hotspots. This paper also analyzes the causes, water quality and quantity characteristics, and variation laws of CSOs pollution, and then discusses various measures from two aspects: reducing the frequency of overflow pollution and controlling after overflow pollution. Finally, this paper summarized and prospected the development of CSOs pollution control in China.
2023, 41(12): 48-53,115.
doi: 10.13205/j.hjgc.202312005
Abstract:
This study took a sponge reconstruction community in Tianjin as the research object, and used a combination of online monitoring and model simulation to conduct a quantitative evaluation of the control effect of sponge construction on runoff and water quality at the community scale. We built a stormwater management model, calibrated, and verified the key parameters of the model using the measured rainfall, water volume and water quality data, and simulated and analyzed the control effect and difference of sponge transformation on the total runoff, runoff peak value, and runoff pollution under the scenarios of design rainfall, actual field rainfall, and multi-year continuous rainfall. The results showed the total runoff volume control rate was 64.43% to 74.10%, the runoff volume reduction rate was 31.27% to 40.09% for the sponge community, and the peak flow reduction rate was 40.57% to 41.40% for the monitored area with different return periods. The total runoff volume control rate was 58.29% to 100.00%, and the runoff pollution reduction rate was 40.93% to 83.05% under 55 rainfall events. Total rainfall and maximum hourly rainfall were the most important characteristics affecting the efficiencies of runoff control and non-point source pollution reduction, with a strong negative correlation (P<0.01). The total runoff volume control rate was 78.61%, the runoff volume reduction rate was 37.18%, and the runoff pollution reduction rate was 45.16% with years of continuous rainfall. The results provided a reference for evaluating the effects of runoff control and non-point source pollution reduction at a community scale after the sponge reconstruction.
This study took a sponge reconstruction community in Tianjin as the research object, and used a combination of online monitoring and model simulation to conduct a quantitative evaluation of the control effect of sponge construction on runoff and water quality at the community scale. We built a stormwater management model, calibrated, and verified the key parameters of the model using the measured rainfall, water volume and water quality data, and simulated and analyzed the control effect and difference of sponge transformation on the total runoff, runoff peak value, and runoff pollution under the scenarios of design rainfall, actual field rainfall, and multi-year continuous rainfall. The results showed the total runoff volume control rate was 64.43% to 74.10%, the runoff volume reduction rate was 31.27% to 40.09% for the sponge community, and the peak flow reduction rate was 40.57% to 41.40% for the monitored area with different return periods. The total runoff volume control rate was 58.29% to 100.00%, and the runoff pollution reduction rate was 40.93% to 83.05% under 55 rainfall events. Total rainfall and maximum hourly rainfall were the most important characteristics affecting the efficiencies of runoff control and non-point source pollution reduction, with a strong negative correlation (P<0.01). The total runoff volume control rate was 78.61%, the runoff volume reduction rate was 37.18%, and the runoff pollution reduction rate was 45.16% with years of continuous rainfall. The results provided a reference for evaluating the effects of runoff control and non-point source pollution reduction at a community scale after the sponge reconstruction.
2023, 41(12): 54-60,181.
doi: 10.13205/j.hjgc.202312006
Abstract:
Wet-weather discharges from stormwater pumping stations in separate stormwater drainage systems contribute to the deterioration of river water quality. Understanding the pollution mechanism of pumping discharge is the key to alleviating wet-weather pollution and improving water quality. To identify the dominant factors for controlling wet-weather discharge pollution, this study employed back propagation neural network (BPNN) and radial basis neural network (RBNN) models to establish the nonlinear relationships between 11 input parameters (i.e., rainfall and stormwater network operation) and the wet-weather discharge pollution from two pumping stations in separate stormwater drainage systems in downtown Shanghai. The findings indicated that RBNN performs better in simulating wet-weather pumping discharge pollution than BPNN. For water quality indicators of COD, NH3-N, and SS, the RBNN achieved a higher performance of 15.6% to 31.9%, 12.3%~18.3%, and 12.6%~53.9%, respectively than BPNN, measuring by average absolute error, root mean square error, and average percentage error, respectively. Coefficients of determination were improved by 3.1%~5.4% when comparing RBNN with BPNN. Moreover, the importance ranking of input parameters using RBNN identified five key parameters, including time duration between two consecutive pump operation events, wet-well water level for starting the pumps, peak rainfall intensity, antecedent dry-weather periods, and wet-well level for stopping the pumps. Actions should be taken to investigate the sewage sources illicitly discharging into storm drains and then correct these illicit discharges. These actions can eliminate the sewage accommodation and the corresponding accumulated pollutant deposits within the storm pipes on dry-weather days, which are inappropriately flushed into the receiving waters during the operation of wet-weather storm pumps. Therefore, the wet-weather discharge pollution would be obviously alleviated. Optimizing the in-pipe water level to stop stormwater pumps, can also aid in reducing the wet-weather discharge pollution.
Wet-weather discharges from stormwater pumping stations in separate stormwater drainage systems contribute to the deterioration of river water quality. Understanding the pollution mechanism of pumping discharge is the key to alleviating wet-weather pollution and improving water quality. To identify the dominant factors for controlling wet-weather discharge pollution, this study employed back propagation neural network (BPNN) and radial basis neural network (RBNN) models to establish the nonlinear relationships between 11 input parameters (i.e., rainfall and stormwater network operation) and the wet-weather discharge pollution from two pumping stations in separate stormwater drainage systems in downtown Shanghai. The findings indicated that RBNN performs better in simulating wet-weather pumping discharge pollution than BPNN. For water quality indicators of COD, NH3-N, and SS, the RBNN achieved a higher performance of 15.6% to 31.9%, 12.3%~18.3%, and 12.6%~53.9%, respectively than BPNN, measuring by average absolute error, root mean square error, and average percentage error, respectively. Coefficients of determination were improved by 3.1%~5.4% when comparing RBNN with BPNN. Moreover, the importance ranking of input parameters using RBNN identified five key parameters, including time duration between two consecutive pump operation events, wet-well water level for starting the pumps, peak rainfall intensity, antecedent dry-weather periods, and wet-well level for stopping the pumps. Actions should be taken to investigate the sewage sources illicitly discharging into storm drains and then correct these illicit discharges. These actions can eliminate the sewage accommodation and the corresponding accumulated pollutant deposits within the storm pipes on dry-weather days, which are inappropriately flushed into the receiving waters during the operation of wet-weather storm pumps. Therefore, the wet-weather discharge pollution would be obviously alleviated. Optimizing the in-pipe water level to stop stormwater pumps, can also aid in reducing the wet-weather discharge pollution.
2023, 41(12): 61-69,255.
doi: 10.13205/j.hjgc.202312007
Abstract:
With the rapid development of urbanization, the pressure of urban drainage and the occurrence of waterlogging is increasing, and enhancing the "resilience" of rainwater drainage systems is an urgent need of urban development. This study selected a certain area of a plain river network city in the Yangtze River Delta as the research object. Based on the calibrated SWMM model and the existing research result, a resilience evaluation model of the rainwater drainage system was established from two aspects: the amount of waterlogging, and the duration of the system. We ran the model under different rainfall scenarios to analyze the resilience of the rainwater drainage system in the study area. The results show that as the rainfall intensity increases, the system resilience gradually decreases,which means that there is a negatiue linear correlation between the system resilience value and the increase in rainfall intensity. Under the conditions of low recurrence period, the decrease in resilient value is relatively smaller with the increase of rainfall intensity. The larger the recurrence period, the faster the decrease rate of system resilient value. Under the same rainfall recurrence period, as the proportion of impermeable ground increases, the system resilience gradually decreases. In the case of high recurrence period and high proportion of impermeable ground, the system resilient value is relatively lower; under the condition of rainfall with a return period of 10 years, the proportion of impermeable ground in the region increases, and the system's resilient value decreases the fastest. Introducing the concept of resilience into urban rainwater drainage systems and establishing an evaluation system that reflects the resilience of the system in response to external environmental changes and disasters can help comprehensively understand the performance of rainwater drainage systems. It is of great significance for the transformation and optimization of rainwater drainage systems and helpful for urban risk management.
With the rapid development of urbanization, the pressure of urban drainage and the occurrence of waterlogging is increasing, and enhancing the "resilience" of rainwater drainage systems is an urgent need of urban development. This study selected a certain area of a plain river network city in the Yangtze River Delta as the research object. Based on the calibrated SWMM model and the existing research result, a resilience evaluation model of the rainwater drainage system was established from two aspects: the amount of waterlogging, and the duration of the system. We ran the model under different rainfall scenarios to analyze the resilience of the rainwater drainage system in the study area. The results show that as the rainfall intensity increases, the system resilience gradually decreases,which means that there is a negatiue linear correlation between the system resilience value and the increase in rainfall intensity. Under the conditions of low recurrence period, the decrease in resilient value is relatively smaller with the increase of rainfall intensity. The larger the recurrence period, the faster the decrease rate of system resilient value. Under the same rainfall recurrence period, as the proportion of impermeable ground increases, the system resilience gradually decreases. In the case of high recurrence period and high proportion of impermeable ground, the system resilient value is relatively lower; under the condition of rainfall with a return period of 10 years, the proportion of impermeable ground in the region increases, and the system's resilient value decreases the fastest. Introducing the concept of resilience into urban rainwater drainage systems and establishing an evaluation system that reflects the resilience of the system in response to external environmental changes and disasters can help comprehensively understand the performance of rainwater drainage systems. It is of great significance for the transformation and optimization of rainwater drainage systems and helpful for urban risk management.
2023, 41(12): 70-75.
doi: 10.13205/j.hjgc.202312008
Abstract:
Previous studies have shown that the innovative permeable pavement, with capillary columns added into the structural layer, can not only effectively improve the hydrological control effect of facilities applied in high groundwater level areas, thereby alleviating the risk of urban waterlogging, but also effectively alleviate the urban heat island to regulate the urban thermal environment. To investigate the pollution control effect of the innovative permeable pavement on urban stormwater runoff, three kinds of parking lots, innovative permeable pavement (IPP), conventional permeable interlocking concrete pavement (PICP), and impervious concrete pavement (CP) were constructed in the Shanghai urban area. Water quality performances of these three pavements were monitored and analyzed under real rainfall events for the whole year. Results showed that the total pollution load control rates of IPP for NO3--N, TN increased from 14.4% and 37.3% to 45.6% and 58.8%, respectively, compared with those values of PICP; the total pollution load control rates of IPP for TSS and COD increased from 81.9% and 84.2% to 97.5% and 96.7%, respectively; moreover, both PICP and IPP had good removal effect on TP, with total pollution load control rates of 82.5% and 86.2%, respectively, indicating that IPP can significantly reduce the emission of NO3--N, TN, TSS and COD, compared with PICP, so as to effectively alleviate the urban non-point source pollution caused by stormwater runoff.
Previous studies have shown that the innovative permeable pavement, with capillary columns added into the structural layer, can not only effectively improve the hydrological control effect of facilities applied in high groundwater level areas, thereby alleviating the risk of urban waterlogging, but also effectively alleviate the urban heat island to regulate the urban thermal environment. To investigate the pollution control effect of the innovative permeable pavement on urban stormwater runoff, three kinds of parking lots, innovative permeable pavement (IPP), conventional permeable interlocking concrete pavement (PICP), and impervious concrete pavement (CP) were constructed in the Shanghai urban area. Water quality performances of these three pavements were monitored and analyzed under real rainfall events for the whole year. Results showed that the total pollution load control rates of IPP for NO3--N, TN increased from 14.4% and 37.3% to 45.6% and 58.8%, respectively, compared with those values of PICP; the total pollution load control rates of IPP for TSS and COD increased from 81.9% and 84.2% to 97.5% and 96.7%, respectively; moreover, both PICP and IPP had good removal effect on TP, with total pollution load control rates of 82.5% and 86.2%, respectively, indicating that IPP can significantly reduce the emission of NO3--N, TN, TSS and COD, compared with PICP, so as to effectively alleviate the urban non-point source pollution caused by stormwater runoff.
2023, 41(12): 76-81.
doi: 10.13205/j.hjgc.202312009
Abstract:
Dispersed small-scale sponge facilities with porous materials as the base material are widely used currently. To continuously improve the porosity, strength, water absorption, and release capacity of the material without secondary pollution, and adapt to more application scenarios, the modification of porous foam glass was studied. The waste glass powder was used as the main raw material, adding a certain amount of foaming agent, modifier, etc., and then the foam glass with an open-cell structure was prepared. The firing temperature was 500~950 ℃. The prepared open-cell foam glass's microstructure and physical properties were tested. The results showed that the prepared foam glass has many dense and irregular open-cell structures, and the cells relate to each other. The cell diameter is about 0.1 mm to 5 mm, and the porosity rate reaches 93%. The foam glass with a compressive strength of 2.3 MPa can be applied to scenarios with high requirements for compressive strength. By controlling the raw materials, the content of heavy metal pollutants is extremely low without causing pollution to water bodies. The foam glass has strong water absorption and a good sustained release effect, and the saturation water absorption can reach 95%. After 8 h of water release, the water absorption rate (by mass) is reduced to 30%. When used in underground enclosed environments, exhaust design and anti-floating design need to be considered. The study provides a new environmental substrate for stormwater storage and drainage in sponge city, and promotes the application of foam glass in sponge facilities.
Dispersed small-scale sponge facilities with porous materials as the base material are widely used currently. To continuously improve the porosity, strength, water absorption, and release capacity of the material without secondary pollution, and adapt to more application scenarios, the modification of porous foam glass was studied. The waste glass powder was used as the main raw material, adding a certain amount of foaming agent, modifier, etc., and then the foam glass with an open-cell structure was prepared. The firing temperature was 500~950 ℃. The prepared open-cell foam glass's microstructure and physical properties were tested. The results showed that the prepared foam glass has many dense and irregular open-cell structures, and the cells relate to each other. The cell diameter is about 0.1 mm to 5 mm, and the porosity rate reaches 93%. The foam glass with a compressive strength of 2.3 MPa can be applied to scenarios with high requirements for compressive strength. By controlling the raw materials, the content of heavy metal pollutants is extremely low without causing pollution to water bodies. The foam glass has strong water absorption and a good sustained release effect, and the saturation water absorption can reach 95%. After 8 h of water release, the water absorption rate (by mass) is reduced to 30%. When used in underground enclosed environments, exhaust design and anti-floating design need to be considered. The study provides a new environmental substrate for stormwater storage and drainage in sponge city, and promotes the application of foam glass in sponge facilities.
2023, 41(12): 82-88.
doi: 10.13205/j.hjgc.202312010
Abstract:
The establishment of submerged zones and the addition of carbon sources in bioretention facilities is a common method for enhancing nitrogen removal at present, which makes the submerged zone the main site for denitrification and an important factor affecting the efficiency of bioretention facilities. However, few researchers have studied the effects of the types and locations of carbon sources in bioretention facilities on water quality of submerged zones. Based on the ability of simultaneous nitrogen and phosphorus removal of pyrite, the effect of carbon source on water quality in the submerged zone was studied by changing the type of carbon sources (corncob, rice husk, woodchips) and dosing locations of carbon source corncob in pyrite-based bioretention facility. The results showed that NO3--N removal rate of the three carbon sources was in the order of woodchips > rice husk > corn cob, and the woodchips did not cause a decrease in removal efficiency of NH4+-N. Further study on the water quality of the submerged zone showed that NH4+-N and PO43--P were lower in the submerged zone after the addition of woodchips, and the removal efficiency of NO3--N was higher. The carbon source added to the mulching layer led to a better NH4+-N and PO43--P removal performance, but a slightly lower removal performance of NO3--N. In the submerged zone, the addition of carbon sources in the mulching layer helped maintain a lower and stable NH4+-N concentration and provided appropriate COD to continuously reduce NO3--N. More importantly, when the carbon source was added in the vadose zone and mulching layer, the denitrification mainly occurred during drought, while when the carbon source was added in the submerged zone, the denitrification mainly occurred during rainfall.
The establishment of submerged zones and the addition of carbon sources in bioretention facilities is a common method for enhancing nitrogen removal at present, which makes the submerged zone the main site for denitrification and an important factor affecting the efficiency of bioretention facilities. However, few researchers have studied the effects of the types and locations of carbon sources in bioretention facilities on water quality of submerged zones. Based on the ability of simultaneous nitrogen and phosphorus removal of pyrite, the effect of carbon source on water quality in the submerged zone was studied by changing the type of carbon sources (corncob, rice husk, woodchips) and dosing locations of carbon source corncob in pyrite-based bioretention facility. The results showed that NO3--N removal rate of the three carbon sources was in the order of woodchips > rice husk > corn cob, and the woodchips did not cause a decrease in removal efficiency of NH4+-N. Further study on the water quality of the submerged zone showed that NH4+-N and PO43--P were lower in the submerged zone after the addition of woodchips, and the removal efficiency of NO3--N was higher. The carbon source added to the mulching layer led to a better NH4+-N and PO43--P removal performance, but a slightly lower removal performance of NO3--N. In the submerged zone, the addition of carbon sources in the mulching layer helped maintain a lower and stable NH4+-N concentration and provided appropriate COD to continuously reduce NO3--N. More importantly, when the carbon source was added in the vadose zone and mulching layer, the denitrification mainly occurred during drought, while when the carbon source was added in the submerged zone, the denitrification mainly occurred during rainfall.
2023, 41(12): 89-98.
doi: 10.13205/j.hjgc.202312011
Abstract:
The release of nitrogen and phosphorus from pipe sediments during stormwater runoff is the main cause of eutrophication in receiving waters. However, different receiving waters have different effects on the transport and transformation of nitrogen and phosphorus in pipeline sediments due to different water quality factors such as pH, temperature, and initial concentration of nitrogen and phosphorus. Therefore, in this study, we collected pipeline sediments, reclaimed water and natural river water, analyzed the pollution characteristics of the sediments and water samples, and then simulated the process of pipeline sediments entering into different receiving waters by mixing the sediments with different water bodies, explored the characteristics and mechanism of nitrogen and phosphorus release, and analyzed the effects of typical water environment factors on the release of nitrogen and phosphorus from pipeline sediments. The results showed that both river water and reclaimed water had a promoting effect on the release of nitrogen (including total nitrogen TN and ammonia nitrogen NH4+-N) in pipeline sediments, while inhibiting the release of total phosphorus (TP), in which the reclaimed water had a stronger promoting effect on the release of total nitrogen and ammonia nitrogen (NH4+-N) but a stronger inhibiting effect on the release of total phosphorus; the releases of TP, NH4+-N and TN from the pipeline sediments were reduced with the increase of pH The release fluxes of the three substances in different environments were in the following order: acidic>neutral>alkaline, which might be related to ion exchange and physical adsorption in the aqueous environment; the release intensity of TP, NH4+-N and TN in pipeline sediments was enhanced with increasing temperature; the release of TP and NH4+-N from pipeline sediments was inhibited with the increase of the concentrations of TP and NH4+-N in the aqueous environment When the initial TP and NH4+-N concentrations were 0.232 mg/L and 0.240 mg/L, respectively, their corresponding equilibrium concentrations of nitrogen and phosphorus release were reached. This study helps to understand the mechanism of nitrogen and phosphorus release from pipeline sediments into different receiving water bodies, with a view to providing a scientific basis for the regulation of eutrophication pollution in urban landscape water bodies caused by stormwater runoff pollution.
The release of nitrogen and phosphorus from pipe sediments during stormwater runoff is the main cause of eutrophication in receiving waters. However, different receiving waters have different effects on the transport and transformation of nitrogen and phosphorus in pipeline sediments due to different water quality factors such as pH, temperature, and initial concentration of nitrogen and phosphorus. Therefore, in this study, we collected pipeline sediments, reclaimed water and natural river water, analyzed the pollution characteristics of the sediments and water samples, and then simulated the process of pipeline sediments entering into different receiving waters by mixing the sediments with different water bodies, explored the characteristics and mechanism of nitrogen and phosphorus release, and analyzed the effects of typical water environment factors on the release of nitrogen and phosphorus from pipeline sediments. The results showed that both river water and reclaimed water had a promoting effect on the release of nitrogen (including total nitrogen TN and ammonia nitrogen NH4+-N) in pipeline sediments, while inhibiting the release of total phosphorus (TP), in which the reclaimed water had a stronger promoting effect on the release of total nitrogen and ammonia nitrogen (NH4+-N) but a stronger inhibiting effect on the release of total phosphorus; the releases of TP, NH4+-N and TN from the pipeline sediments were reduced with the increase of pH The release fluxes of the three substances in different environments were in the following order: acidic>neutral>alkaline, which might be related to ion exchange and physical adsorption in the aqueous environment; the release intensity of TP, NH4+-N and TN in pipeline sediments was enhanced with increasing temperature; the release of TP and NH4+-N from pipeline sediments was inhibited with the increase of the concentrations of TP and NH4+-N in the aqueous environment When the initial TP and NH4+-N concentrations were 0.232 mg/L and 0.240 mg/L, respectively, their corresponding equilibrium concentrations of nitrogen and phosphorus release were reached. This study helps to understand the mechanism of nitrogen and phosphorus release from pipeline sediments into different receiving water bodies, with a view to providing a scientific basis for the regulation of eutrophication pollution in urban landscape water bodies caused by stormwater runoff pollution.
2023, 41(12): 99-106.
doi: 10.13205/j.hjgc.202312012
Abstract:
Considering the issue of inconsistent adherence to water environment quality standards due to pollution from rainfall overflow, the technical approach to managing dynamic water environments in small watersheds in Shenzhen was investigated. Firstly, by utilizing comprehensive continuous water quality data of full coverage, the rivers exceeding standard levels during the rainy season and their corresponding overflow outlets were accurately identified as treatment targets. Secondly, a holistic investigation was conducted within each small watershed where these rivers and overflow outlets were located in order to systematically identify various existing water environment problems. This facilitated the establishment of problem-measure-target relationships and rectification task ledgers aimed at promoting effective remediation efforts. Finally, based on the implementation of the measures and the results of water quality monitoring, the standard assessment and water quality inspection in rainy season are carried out in the small watershed after renovation, and dynamic management is implemented. After over one year of exploration and implementation, there has been a 7.73% annual increase in the proportion of river monitoring sections meeting or surpassing Class III standards during the rainy season; additionally, there has been a yearly reduction of more than 25% in flood season overflow pollution intensity across three major national sections. These achievements demonstrate certain results in preventing and controlling rainfall overflow pollution during the rainy season. The findings presented herein can serve as valuable references for other cities seeking to address similar issues related to rainfall overflow pollution prevention and control.
Considering the issue of inconsistent adherence to water environment quality standards due to pollution from rainfall overflow, the technical approach to managing dynamic water environments in small watersheds in Shenzhen was investigated. Firstly, by utilizing comprehensive continuous water quality data of full coverage, the rivers exceeding standard levels during the rainy season and their corresponding overflow outlets were accurately identified as treatment targets. Secondly, a holistic investigation was conducted within each small watershed where these rivers and overflow outlets were located in order to systematically identify various existing water environment problems. This facilitated the establishment of problem-measure-target relationships and rectification task ledgers aimed at promoting effective remediation efforts. Finally, based on the implementation of the measures and the results of water quality monitoring, the standard assessment and water quality inspection in rainy season are carried out in the small watershed after renovation, and dynamic management is implemented. After over one year of exploration and implementation, there has been a 7.73% annual increase in the proportion of river monitoring sections meeting or surpassing Class III standards during the rainy season; additionally, there has been a yearly reduction of more than 25% in flood season overflow pollution intensity across three major national sections. These achievements demonstrate certain results in preventing and controlling rainfall overflow pollution during the rainy season. The findings presented herein can serve as valuable references for other cities seeking to address similar issues related to rainfall overflow pollution prevention and control.
2023, 41(12): 107-115.
doi: 10.13205/j.hjgc.202312013
Abstract:
Using an anaerobic/anoxic/aerobic sequencing batch reactor (An/A/O-SBR), the long-term impact of temperature (T=32, 27, 22, 17,12 ℃) on denitrification phosphorus removal performance and N2O emission characteristics was investigated with five stages. The characteristics of anoxic nitrogen and phosphorus removal, as well as N2O release in the system under different temperature conditions were investigated. Based on the analysis of the degradation characteristics of microbial flora, the competitive characteristics between the phosphorus accumulating bacteria (PAOs) and the glycogen accumulating bacteria (GAOs) were determined under different temperatures as well. The results showed that the denitrification and phosphorus removal performance of An/A/O-SBR increased first and then decreased with the temperature decreasing. The NOx- and TP removal efficiencies reached 95.5% and 90.3%, respectively, and the N2O yield decreased to 3.71% at 22 ℃. To some extent, the low temperature promoted the competitive advantage of PAOs. The proportion of PHB in the synthetic PHA during the anaerobic stage (ΔPHB/ΔPHA), the proportion of PHB consumed in PHA (PHBcon/PHAcon), the proportion of glycogen synthesized in PHA consumed during the anoxic (Glyin/PHAcon) were gradually close to the degradation characteristics of PAOs. The denitrification process of GAOs does not absorb excessive phosphorus, resulting in the reduction of TP removal efficiency. Under lower temperatures, both the enzymatic reaction rate and the electron providing rate by PHA decreased, which led to the decrease of NO3- removal rate and the increase of N2O yield in the anoxic stage. Higher temperatures promoted the proliferation of GAOs in the An/A/O-SBR system.
Using an anaerobic/anoxic/aerobic sequencing batch reactor (An/A/O-SBR), the long-term impact of temperature (T=32, 27, 22, 17,12 ℃) on denitrification phosphorus removal performance and N2O emission characteristics was investigated with five stages. The characteristics of anoxic nitrogen and phosphorus removal, as well as N2O release in the system under different temperature conditions were investigated. Based on the analysis of the degradation characteristics of microbial flora, the competitive characteristics between the phosphorus accumulating bacteria (PAOs) and the glycogen accumulating bacteria (GAOs) were determined under different temperatures as well. The results showed that the denitrification and phosphorus removal performance of An/A/O-SBR increased first and then decreased with the temperature decreasing. The NOx- and TP removal efficiencies reached 95.5% and 90.3%, respectively, and the N2O yield decreased to 3.71% at 22 ℃. To some extent, the low temperature promoted the competitive advantage of PAOs. The proportion of PHB in the synthetic PHA during the anaerobic stage (ΔPHB/ΔPHA), the proportion of PHB consumed in PHA (PHBcon/PHAcon), the proportion of glycogen synthesized in PHA consumed during the anoxic (Glyin/PHAcon) were gradually close to the degradation characteristics of PAOs. The denitrification process of GAOs does not absorb excessive phosphorus, resulting in the reduction of TP removal efficiency. Under lower temperatures, both the enzymatic reaction rate and the electron providing rate by PHA decreased, which led to the decrease of NO3- removal rate and the increase of N2O yield in the anoxic stage. Higher temperatures promoted the proliferation of GAOs in the An/A/O-SBR system.
2023, 41(12): 116-122,149.
doi: 10.13205/j.hjgc.202312014
Abstract:
Ecotype-microbial fuel cell (E-MFC) is a novel wastewater treatment technology that combines microbial fuel cell (MFC) with aquatic animals and plants. To study the symbiotic synergy among "microorganisms, aquatic plants and benthic animals" in E-MFC, a series of reactors consisting of sediment MFC (S-MFC), wetland plant MFC (WP-MFC, planting aquatic plants) and ecotype-MFC (E-MFC, introducing aquatic plants and benthic animals) were set up in this experiment, to test their electricity production capacity and nitrogen removal effects. The effects of hydraulic retention time (HRT) and cathode aeration on nitrogen removal and electricity production of the E-MFC were investigated, and the main nitrogen removal mechanisms were discussed. The results showed that the nitrogen removal and electricity production performance of the E-MFC were better than the other two reactors. When treating the same amount of organic wastewater, the maximum power density of E-MFC was 129.4% and 47.2% higher than that of S-MFC and WP-MFC, ammonia nitrogen removal efficiency was 37.6% and 11.2% higher, respectively, and nitrate nitrogen removal efficiency reached 96% above. Further research showed that when HRT was 72 h and water inflow was 0.50 L/d, the E-MFC obtained the highest output voltage of 463 mV, and the corresponding output power density was 27.31 mW/m2. When the cathodic aeration rate was 60 L/h, the maximum output power reached 38.12 mW/m2. In the E-MFC, the disturbance and other activities of aquatic animals enhanced oxygen mass transfer, organic matter decomposition, and nutrient cycling, providing sufficient nutrients for plant growth. In addition, root oxygen secretion also maintained good environmental conditions for the growth and metabolism of rhizosphere microorganisms. Microorganisms, aquatic plants, and benthic animals in the E-MFC formed a relationship of mutual promotion and synergy, thus strengthening the removal of nitrogen from wastewater. As a new ecological restoration technology, E-MFC can recover electric energy and have a good development prospect in the field of wastewater treatment.
Ecotype-microbial fuel cell (E-MFC) is a novel wastewater treatment technology that combines microbial fuel cell (MFC) with aquatic animals and plants. To study the symbiotic synergy among "microorganisms, aquatic plants and benthic animals" in E-MFC, a series of reactors consisting of sediment MFC (S-MFC), wetland plant MFC (WP-MFC, planting aquatic plants) and ecotype-MFC (E-MFC, introducing aquatic plants and benthic animals) were set up in this experiment, to test their electricity production capacity and nitrogen removal effects. The effects of hydraulic retention time (HRT) and cathode aeration on nitrogen removal and electricity production of the E-MFC were investigated, and the main nitrogen removal mechanisms were discussed. The results showed that the nitrogen removal and electricity production performance of the E-MFC were better than the other two reactors. When treating the same amount of organic wastewater, the maximum power density of E-MFC was 129.4% and 47.2% higher than that of S-MFC and WP-MFC, ammonia nitrogen removal efficiency was 37.6% and 11.2% higher, respectively, and nitrate nitrogen removal efficiency reached 96% above. Further research showed that when HRT was 72 h and water inflow was 0.50 L/d, the E-MFC obtained the highest output voltage of 463 mV, and the corresponding output power density was 27.31 mW/m2. When the cathodic aeration rate was 60 L/h, the maximum output power reached 38.12 mW/m2. In the E-MFC, the disturbance and other activities of aquatic animals enhanced oxygen mass transfer, organic matter decomposition, and nutrient cycling, providing sufficient nutrients for plant growth. In addition, root oxygen secretion also maintained good environmental conditions for the growth and metabolism of rhizosphere microorganisms. Microorganisms, aquatic plants, and benthic animals in the E-MFC formed a relationship of mutual promotion and synergy, thus strengthening the removal of nitrogen from wastewater. As a new ecological restoration technology, E-MFC can recover electric energy and have a good development prospect in the field of wastewater treatment.
2023, 41(12): 123-130.
doi: 10.13205/j.hjgc.202312015
Abstract:
The denitrifying sulfur oxidation process is one of the most potential sewage treatment technologies in biological treatment for treating sulfur-containing and nitrogen-containing organic wastewater. In order to understand the information of bacteria that mainly play a role in the denitrifying sulfur oxidation process, three expanded granular sludge bed reactors were operated simultaneously to determine the oxidation efficiency of sulfur denitrification, analyze the changes of the microbial community structure of activated sludge, isolate and screen out the strains in activated sludge and verify their function. The results showed that 100% of 100 mg/L NO3--N and 100 mg/L Ac--C can be removed after stable operation of the three reactors, and up to 90% of 200 mg/L S2- can be removed. 16S rRNA analysis was used to analyze the microbial community structure and diversity of activated sludge in the stable operation reactor, and found that the five genera with high relative abundance were Azoarcus, Pseudomonas, Thauera, Arthrobacter and Desulfomicrobium. A total of 50 strains belonging to 19 genera were obtained by plate separation and flow cytometry separation, and the removal rate of carbon, nitrogen and sulfur pollutants was synthesized to preliminarily determine that Azoarcus, Thauera, Pseudomonas, Acinetobacter and Agrobacterium were the functional genera of denitrified sulfur oxidation process.
The denitrifying sulfur oxidation process is one of the most potential sewage treatment technologies in biological treatment for treating sulfur-containing and nitrogen-containing organic wastewater. In order to understand the information of bacteria that mainly play a role in the denitrifying sulfur oxidation process, three expanded granular sludge bed reactors were operated simultaneously to determine the oxidation efficiency of sulfur denitrification, analyze the changes of the microbial community structure of activated sludge, isolate and screen out the strains in activated sludge and verify their function. The results showed that 100% of 100 mg/L NO3--N and 100 mg/L Ac--C can be removed after stable operation of the three reactors, and up to 90% of 200 mg/L S2- can be removed. 16S rRNA analysis was used to analyze the microbial community structure and diversity of activated sludge in the stable operation reactor, and found that the five genera with high relative abundance were Azoarcus, Pseudomonas, Thauera, Arthrobacter and Desulfomicrobium. A total of 50 strains belonging to 19 genera were obtained by plate separation and flow cytometry separation, and the removal rate of carbon, nitrogen and sulfur pollutants was synthesized to preliminarily determine that Azoarcus, Thauera, Pseudomonas, Acinetobacter and Agrobacterium were the functional genera of denitrified sulfur oxidation process.
2023, 41(12): 131-141.
doi: 10.13205/j.hjgc.202312016
Abstract:
With the improvement of the coverage of domestic sewage network and the successive control of point source discharge of industrial wastewater, agricultural non-point source pollution has become the main problem affecting the improvement of surface water quality. In this study, a control technology for phosphate, a key pollutant in the P River of Shenzhen was proposed, by adsorption of metal modified biochar. Common local abundant biomass of landscape plants was used as the raw material, and Ca, Fe and Mg, which are non-toxic to plants, were selected as the modifier. The optimal pyrolysis temperatures were determined to be 500 ℃, 400 ℃ and 600 ℃, and three kinds of metal modified biochar (CaBC500, FeBC400, and MgBC600) were prepared. The results showed that under the condition of phosphate concentration of 14 mg/L and an initial pH of 8, the optimal dosage of CaBC500, FeBC400 and MgBC600 was 0.8 g, 0.8 g and 1.0 g, respectively. The highest phosphorus removal rates were 84%, 92% and 97%, respectively. The static phosphate adsorption capacities of CaBC500, FeBC400 and MgBC600 were 65.5 mg/g, 69.3 mg/g and 49.3 mg/g, respectively. Through SEM, EDS, BET, FITR and XRD characterization, as well as the construction of adsorption kinetics, thermodynamics and isothermal curve models, it can be found that the adsorption process accords with the pseudo-second-order and Langmuir models, and the phosphorus adsorption mechanisms includes surface precipitation, complex crystallization, ligand exchange and electrostatic attraction. The adsorption and removal of phosphorus can be effectively achieved by using metal modified biochar, indicating its practical application potential.
With the improvement of the coverage of domestic sewage network and the successive control of point source discharge of industrial wastewater, agricultural non-point source pollution has become the main problem affecting the improvement of surface water quality. In this study, a control technology for phosphate, a key pollutant in the P River of Shenzhen was proposed, by adsorption of metal modified biochar. Common local abundant biomass of landscape plants was used as the raw material, and Ca, Fe and Mg, which are non-toxic to plants, were selected as the modifier. The optimal pyrolysis temperatures were determined to be 500 ℃, 400 ℃ and 600 ℃, and three kinds of metal modified biochar (CaBC500, FeBC400, and MgBC600) were prepared. The results showed that under the condition of phosphate concentration of 14 mg/L and an initial pH of 8, the optimal dosage of CaBC500, FeBC400 and MgBC600 was 0.8 g, 0.8 g and 1.0 g, respectively. The highest phosphorus removal rates were 84%, 92% and 97%, respectively. The static phosphate adsorption capacities of CaBC500, FeBC400 and MgBC600 were 65.5 mg/g, 69.3 mg/g and 49.3 mg/g, respectively. Through SEM, EDS, BET, FITR and XRD characterization, as well as the construction of adsorption kinetics, thermodynamics and isothermal curve models, it can be found that the adsorption process accords with the pseudo-second-order and Langmuir models, and the phosphorus adsorption mechanisms includes surface precipitation, complex crystallization, ligand exchange and electrostatic attraction. The adsorption and removal of phosphorus can be effectively achieved by using metal modified biochar, indicating its practical application potential.
2023, 41(12): 142-149.
doi: 10.13205/j.hjgc.202312017
Abstract:
The diffuse pollution estimation with remote sensing (DPeRS) model was conducted to quantify the agricultural spatial diffuse pollution load discharge and river inflow in Xi'an in 2020. The spatial distribution characteristics of surface source pollution were analyzed, the main types of non-point source pollution in the agricultural space of Xi'an were identified, and the targeted prevention and control suggestions for non-point source pollution were also provided. The results showed that the surplus of nitrogen and phosphorus in farmland of agricultural space in Xi'an was large and widely distributed. There were significant differences in the spatial distribution of non-point source pollution emissions. High-value areas were distributed in the east part of Yanliang District, the east part of Gaoling District, the plain area of Zhouzhi County and Chang'an District, and the Lishan hilly area in Lintong District and Lantian County. The nitrogen non-point source pollution is main affected by rural life, and the phosphorus non-point source pollution is mainly affected by soil erosion. The spatial distribution of nitrogen and phosphorus non-point source pollution into the river in agricultural space is similar, but the content is quite different. The high-value areas are located in the east part of Yanliang District, the middle and north part of Lintong District, the Lishan Mountain area of Lantian County, the central and eastern plain area of Zhouzhi County, the shallow mountain area of Qinling Mountains and both sides of some valley roads.
The diffuse pollution estimation with remote sensing (DPeRS) model was conducted to quantify the agricultural spatial diffuse pollution load discharge and river inflow in Xi'an in 2020. The spatial distribution characteristics of surface source pollution were analyzed, the main types of non-point source pollution in the agricultural space of Xi'an were identified, and the targeted prevention and control suggestions for non-point source pollution were also provided. The results showed that the surplus of nitrogen and phosphorus in farmland of agricultural space in Xi'an was large and widely distributed. There were significant differences in the spatial distribution of non-point source pollution emissions. High-value areas were distributed in the east part of Yanliang District, the east part of Gaoling District, the plain area of Zhouzhi County and Chang'an District, and the Lishan hilly area in Lintong District and Lantian County. The nitrogen non-point source pollution is main affected by rural life, and the phosphorus non-point source pollution is mainly affected by soil erosion. The spatial distribution of nitrogen and phosphorus non-point source pollution into the river in agricultural space is similar, but the content is quite different. The high-value areas are located in the east part of Yanliang District, the middle and north part of Lintong District, the Lishan Mountain area of Lantian County, the central and eastern plain area of Zhouzhi County, the shallow mountain area of Qinling Mountains and both sides of some valley roads.
2023, 41(12): 150-157.
doi: 10.13205/j.hjgc.202312018
Abstract:
Due to the increasing application of chemical fertilizers and pesticides in farmland and the random discharge of rural domestic sewage, the treatment of farmland non-point source pollution in Liaohe River is facing great challenges. At present, there is still a lack of scientific and effective evaluation methods on the farmland non-point source pollution control. In this study, an evaluation index system of farmland non-point source pollution control technology was constructed with 1 target layer, 3 criteria layers, 5 indicator layers, and 14 sub-indicator layers. According to the expert rating, the analytic hierarchy process (AHP) and fuzzy comprehensive evaluation (FCE) method were applied to evaluate the 10 typical farmland non-point source pollution control technologies comprehensively and quantitatively. AHP method and Spyder Software were used to calculate the index weight value. The results showed that the comprehensive weight values of ammonia nitrogen removal rate, TP removal rate, water quality purification efficiency, project operation cost, winter purification stability and landscape diversity index were the highest, which were the most important evaluation indexes in selecting the farmland non-point source pollution treatment technology for Liaohe River. The FCE method and Matlab software were used to calculate the index subordination degree and fuzzy comprehensive evaluation value. The results showed that ecological interception ditch technology was the best technology among process interception technologies with a fuzzy comprehensive index value of 3.8872; the constructed wetland technology was the optimal technology of the terminal treatment technologies with a fuzzy comprehensive evaluation value of 3.9304. This study provides a theoretical basis for selecting suitable farmland non-point source pollution control technology in Liaohe River, and also provides effective support for the evaluation of other similar pollution control technology and formulation of relevant policies.
Due to the increasing application of chemical fertilizers and pesticides in farmland and the random discharge of rural domestic sewage, the treatment of farmland non-point source pollution in Liaohe River is facing great challenges. At present, there is still a lack of scientific and effective evaluation methods on the farmland non-point source pollution control. In this study, an evaluation index system of farmland non-point source pollution control technology was constructed with 1 target layer, 3 criteria layers, 5 indicator layers, and 14 sub-indicator layers. According to the expert rating, the analytic hierarchy process (AHP) and fuzzy comprehensive evaluation (FCE) method were applied to evaluate the 10 typical farmland non-point source pollution control technologies comprehensively and quantitatively. AHP method and Spyder Software were used to calculate the index weight value. The results showed that the comprehensive weight values of ammonia nitrogen removal rate, TP removal rate, water quality purification efficiency, project operation cost, winter purification stability and landscape diversity index were the highest, which were the most important evaluation indexes in selecting the farmland non-point source pollution treatment technology for Liaohe River. The FCE method and Matlab software were used to calculate the index subordination degree and fuzzy comprehensive evaluation value. The results showed that ecological interception ditch technology was the best technology among process interception technologies with a fuzzy comprehensive index value of 3.8872; the constructed wetland technology was the optimal technology of the terminal treatment technologies with a fuzzy comprehensive evaluation value of 3.9304. This study provides a theoretical basis for selecting suitable farmland non-point source pollution control technology in Liaohe River, and also provides effective support for the evaluation of other similar pollution control technology and formulation of relevant policies.
2023, 41(12): 158-165,277.
doi: 10.13205/j.hjgc.202312019
Abstract:
In order to investigate the effect of relative humidity (RH) of high humidity flne gas after desulfurization on the sampling results of PM2.5 concentration from coal-fired power plants, the diffusion dryers were used to control the RH of the flue gas. Particle size distribution, particle loss, and PM2.5 mass concentration were determined with a variety of RHs. The results show that a higher RH of the flue gas led to an increase in the number and mass concentration of PM2.5. For the RH of 40%, the mass concentration of PM2.5 was 22.77 mg/m3 and the total number concentration of PM2.5 was 1.16×106 P/cm3. As the RH of the flue gas increased to 50%, 60%, and 80%, the mass concentration of PM2.5 increased by 1.06, 4.35, 4.69 times; and the number concentration was increased by 1.31, 1.70, 1.76 times, respectively. When using a diffusion drying tube to dehumidify the simulated high-humidity flue gas, the mass concentration of particles collected decreased to varying degrees. At the highest relative humidity (94.9%), the mass concentration of PM2.5 was 27.17 mg/Nm3, and at the humidity of 81.4%, 68.5%, 48.7%, 30.4%, the mass concentration was 14.5%, 28.8%, 43.0%, 45.7% lower than that at the highest humidity. Flue gas dehumidification reduced the loss of PM2.5 in the pipeline and the cutting heads. The mass concentration of PM2.5 collected at relative humidity of 94.9%, 81.4%, 68.5% was 3.02, 2.73, 2.57 times higher than that of the control group. High humidity flue gas dehumidification reduced the moisture content of particulate matter, resulting in a lower measurement result of PM2.5 mass concentration. However, due to the reduction of particulate matter loss, the final collected PM2.5 mass concentration was significantly increased.
In order to investigate the effect of relative humidity (RH) of high humidity flne gas after desulfurization on the sampling results of PM2.5 concentration from coal-fired power plants, the diffusion dryers were used to control the RH of the flue gas. Particle size distribution, particle loss, and PM2.5 mass concentration were determined with a variety of RHs. The results show that a higher RH of the flue gas led to an increase in the number and mass concentration of PM2.5. For the RH of 40%, the mass concentration of PM2.5 was 22.77 mg/m3 and the total number concentration of PM2.5 was 1.16×106 P/cm3. As the RH of the flue gas increased to 50%, 60%, and 80%, the mass concentration of PM2.5 increased by 1.06, 4.35, 4.69 times; and the number concentration was increased by 1.31, 1.70, 1.76 times, respectively. When using a diffusion drying tube to dehumidify the simulated high-humidity flue gas, the mass concentration of particles collected decreased to varying degrees. At the highest relative humidity (94.9%), the mass concentration of PM2.5 was 27.17 mg/Nm3, and at the humidity of 81.4%, 68.5%, 48.7%, 30.4%, the mass concentration was 14.5%, 28.8%, 43.0%, 45.7% lower than that at the highest humidity. Flue gas dehumidification reduced the loss of PM2.5 in the pipeline and the cutting heads. The mass concentration of PM2.5 collected at relative humidity of 94.9%, 81.4%, 68.5% was 3.02, 2.73, 2.57 times higher than that of the control group. High humidity flue gas dehumidification reduced the moisture content of particulate matter, resulting in a lower measurement result of PM2.5 mass concentration. However, due to the reduction of particulate matter loss, the final collected PM2.5 mass concentration was significantly increased.
2023, 41(12): 166-171.
doi: 10.13205/j.hjgc.202312020
Abstract:
In order to understand the spatial and temporal distribution characteristics of air pollutants in highway areas, the G30 Lian-huo Highway in Shandan County, Zhangye City was taken as the research object. Based on field monitoring data, multi-scale geographically weighted regression (MGWR) model was used to define the boundary of air pollutants in highway areas. The temporal and spatial characteristics of the main pollutants (PM2.5, PM10, CO and SO2) and their correlation with traffic and meteorological elements were analyzed. The results showed that: The influence of constant term and boundary distance on Isum (a composite index of ambient air quality) was significantly negative. At the monitoring point 300 meters away from the expressway boundary, the median of the constant term was -0.316, and the mean boundary distance was -1.022. Meanwhile, the regression coefficients of a constant term and boundary distance tended to be stable after 300 meters away from the expressway boundary. Therefore, the boundary of air pollutants in the highway domain was defined as the area within a distance of 300 meters from the highway boundary. In correlation analysis, while CO and SO2 showed significant correlation with traffic volume and meteorological factors, PM10 and PM2.5 showed no significant correlation with traffic volume and meteorological factors. The wind direction had a strong influence on the spatial distribution of PM2.5, PM10 and SO2, but didn't have a positive effect on CO spatial distribution.
In order to understand the spatial and temporal distribution characteristics of air pollutants in highway areas, the G30 Lian-huo Highway in Shandan County, Zhangye City was taken as the research object. Based on field monitoring data, multi-scale geographically weighted regression (MGWR) model was used to define the boundary of air pollutants in highway areas. The temporal and spatial characteristics of the main pollutants (PM2.5, PM10, CO and SO2) and their correlation with traffic and meteorological elements were analyzed. The results showed that: The influence of constant term and boundary distance on Isum (a composite index of ambient air quality) was significantly negative. At the monitoring point 300 meters away from the expressway boundary, the median of the constant term was -0.316, and the mean boundary distance was -1.022. Meanwhile, the regression coefficients of a constant term and boundary distance tended to be stable after 300 meters away from the expressway boundary. Therefore, the boundary of air pollutants in the highway domain was defined as the area within a distance of 300 meters from the highway boundary. In correlation analysis, while CO and SO2 showed significant correlation with traffic volume and meteorological factors, PM10 and PM2.5 showed no significant correlation with traffic volume and meteorological factors. The wind direction had a strong influence on the spatial distribution of PM2.5, PM10 and SO2, but didn't have a positive effect on CO spatial distribution.
2023, 41(12): 172-181.
doi: 10.13205/j.hjgc.202312021
Abstract:
In order to meet the treatment requirement of high concentration H2S after catalytic hydrolysis of blast furnace gas, the ELECNRTL physical property method of ASPEN and JOBACK group contribution method were used to estimate the physical property parameters of EDTA complexed iron with ethylenediamine tetraacetic acid as the ligand raw material. The simulation model of the complete wet desulphurization process with EDTA complexed iron and oxidation regeneration was built. And two reactors, the packed absorption tower, and the aeration regeneration tank, were set as the core unit. Through the single factor analysis, it was found that under the flue gas flow rate of 1000 m3/h, when pH=8, the reaction temperature of the packed column and the regeneration tank was 25 ℃, the reaction pressure was 0.1 MPa, the liquid-gas ratio was 5:1, the concentration of iron complexation was 0.05 mol/L, the residence time was 40 s and the molar ratio of O2-ferrous complexation was 4:1, the model could be optimized with the balance of cost and efficiency. Under these parameters, the H2S absorption rate and the complex ferrous regeneration rate achieved 99.5% and 97.6%, respectively. On this basis, the orthogonal analysis was used to explore the influence of each factor and the model was applied to the design of the actual demonstration project. The project operated well and its result was like the expected values of the model. It indicated that the model has good application potential and can be used to guide engineering design and optimization.
In order to meet the treatment requirement of high concentration H2S after catalytic hydrolysis of blast furnace gas, the ELECNRTL physical property method of ASPEN and JOBACK group contribution method were used to estimate the physical property parameters of EDTA complexed iron with ethylenediamine tetraacetic acid as the ligand raw material. The simulation model of the complete wet desulphurization process with EDTA complexed iron and oxidation regeneration was built. And two reactors, the packed absorption tower, and the aeration regeneration tank, were set as the core unit. Through the single factor analysis, it was found that under the flue gas flow rate of 1000 m3/h, when pH=8, the reaction temperature of the packed column and the regeneration tank was 25 ℃, the reaction pressure was 0.1 MPa, the liquid-gas ratio was 5:1, the concentration of iron complexation was 0.05 mol/L, the residence time was 40 s and the molar ratio of O2-ferrous complexation was 4:1, the model could be optimized with the balance of cost and efficiency. Under these parameters, the H2S absorption rate and the complex ferrous regeneration rate achieved 99.5% and 97.6%, respectively. On this basis, the orthogonal analysis was used to explore the influence of each factor and the model was applied to the design of the actual demonstration project. The project operated well and its result was like the expected values of the model. It indicated that the model has good application potential and can be used to guide engineering design and optimization.
2023, 41(12): 182-189.
doi: 10.13205/j.hjgc.202312022
Abstract:
With the implementation of ultra-low emissions in the iron and steel industry, applying blast furnace gas desulfurization technology is very urgent. The sulfur-containing component in blast furnace gas mainly is carbonyl sulfide (COS), and the catalytic hydrolysis method on the γ-Al2O3-based catalyst is usually selected to generate H2S and then further removed. However, the hydrolysis catalyst is easily deactivated in the presence of HCl from the blast furnace gas. In this work, the γ-Al2O3-based catalyst was prepared by the impregnation method supported with alkali metals, Na or K, as an active component. The effect of HCl on the hydrolysis activity and deactivation mechanism of the catalyst was investigated through the combined platform of a fixed-bed reactor and gas chromatography. The hydrolysis efficiency of COS was tested at 120 ℃, gas hourly space velocity (GHSV) of 150000 h-1. The results showed that hydrolysis efficiency and chlorine resistance on catalysts Na/Al2O3 and K/Al2O3 were higher than that on γ-Al2O3, and the chlorine resistance on Na/Al2O3 was higher than that on K/Al2O3. The active components, Na and K increased the content of alkaline centers of the catalyst, promoted the COS hydrolysis reaction and improved the catalyst activity. The active component Na or K preferentially reacts with HCl to form metal chloride, weakens the chlorination effect of HCl on the support components and improves the chlorine resistance of the catalyst. The deactivation mechanism of Na/Al2O3 and K/Al2O3 catalysts in the presence of HCl was investigated. HCl occupied the medium-strong alkaline center (M—O) of the catalysts and reacted with the active components of alkali metals to form metal chloride (M—Cl), and then reduced the catalyst activity. The loss of Na in Na/Al2O3 in the presence of HCl was significantly lower than K in K/Al2O3, which improved the chlorine resistance of Na/Al2O3 catalyst.
With the implementation of ultra-low emissions in the iron and steel industry, applying blast furnace gas desulfurization technology is very urgent. The sulfur-containing component in blast furnace gas mainly is carbonyl sulfide (COS), and the catalytic hydrolysis method on the γ-Al2O3-based catalyst is usually selected to generate H2S and then further removed. However, the hydrolysis catalyst is easily deactivated in the presence of HCl from the blast furnace gas. In this work, the γ-Al2O3-based catalyst was prepared by the impregnation method supported with alkali metals, Na or K, as an active component. The effect of HCl on the hydrolysis activity and deactivation mechanism of the catalyst was investigated through the combined platform of a fixed-bed reactor and gas chromatography. The hydrolysis efficiency of COS was tested at 120 ℃, gas hourly space velocity (GHSV) of 150000 h-1. The results showed that hydrolysis efficiency and chlorine resistance on catalysts Na/Al2O3 and K/Al2O3 were higher than that on γ-Al2O3, and the chlorine resistance on Na/Al2O3 was higher than that on K/Al2O3. The active components, Na and K increased the content of alkaline centers of the catalyst, promoted the COS hydrolysis reaction and improved the catalyst activity. The active component Na or K preferentially reacts with HCl to form metal chloride, weakens the chlorination effect of HCl on the support components and improves the chlorine resistance of the catalyst. The deactivation mechanism of Na/Al2O3 and K/Al2O3 catalysts in the presence of HCl was investigated. HCl occupied the medium-strong alkaline center (M—O) of the catalysts and reacted with the active components of alkali metals to form metal chloride (M—Cl), and then reduced the catalyst activity. The loss of Na in Na/Al2O3 in the presence of HCl was significantly lower than K in K/Al2O3, which improved the chlorine resistance of Na/Al2O3 catalyst.
2023, 41(12): 190-196,157.
doi: 10.13205/j.hjgc.202312023
Abstract:
Aiming at the problems of large sludge volume and insufficient disposal capacity in China, this paper systematically studied the new lime drying sludge resource utilization method of sludge blending sintering, and comprehensively studied the influence of different sludge blending amounts on sintering mineralization performance, flue gas particles and dioxins emissions. The research showed that when the amount of sludge was less than 1.8%, the yield and drum index decreased slightly, the change in solid fuel consumption was not significant, and the impact on the quality of mineralization was small; the concentration of PM10 and PM2.5 discharged from sintering decreased first and then increased, with the increase of sludge mixing amount. The method can significantly reduce the content of K, Na, Pb, Zn, and Cu elements in fine particles can be significantly reduced; the total mass concentration and total toxic equivalent concentration of dioxins decreased slowly and then increased sharply, with the increase of sludge volume. This method can use lime-dried sludge in large volume and at low cost, and have a good potential in real application.
Aiming at the problems of large sludge volume and insufficient disposal capacity in China, this paper systematically studied the new lime drying sludge resource utilization method of sludge blending sintering, and comprehensively studied the influence of different sludge blending amounts on sintering mineralization performance, flue gas particles and dioxins emissions. The research showed that when the amount of sludge was less than 1.8%, the yield and drum index decreased slightly, the change in solid fuel consumption was not significant, and the impact on the quality of mineralization was small; the concentration of PM10 and PM2.5 discharged from sintering decreased first and then increased, with the increase of sludge mixing amount. The method can significantly reduce the content of K, Na, Pb, Zn, and Cu elements in fine particles can be significantly reduced; the total mass concentration and total toxic equivalent concentration of dioxins decreased slowly and then increased sharply, with the increase of sludge volume. This method can use lime-dried sludge in large volume and at low cost, and have a good potential in real application.
2023, 41(12): 197-205,106.
doi: 10.13205/j.hjgc.202312024
Abstract:
The process of cement kiln pre-decomposition and steel kiln sintering was simulated by the tube furnace combustion experiment. At 900 ℃, the formation characteristics of gaseous pollutants were studied during the heat utilization and co-combustion process of four typical steel smelting solid wastes, namely, the steel dust sludge, the converter dust, the sintered dust, and the blast furnace bag dust with the waste incineration fly ash. The co-combustion of four kinds of solid wastes of iron and steel smelting, and fly ash of waste incineration was carried out at the mass ratio of 2:8, 3:7 and 4:6, respectively. The results showed that the best blend ratios of the steel dust sludge, the converter dust, the sintered dust, and the blast furnace bag dust with the waste incineration fly ash to inhibit the formation of NO and the volatilization of Pb and Zn were 20%, 20%, 30%, and 40%, respectively. Among the four typical steel smelting solid wastes, the co-combustion of converter ash and waste incineration fly ash has the best inhibition effect on NO formation, the co-combustion of blast furnace bag ash and waste incineration fly ash has the most stable inhibition effect on Pb volatilization, and the best inhibition effect on Zn volatilization. Above experimental works are expected to be a scientific theoretical reference for the further technological development on the formation inhibition and emission control of gaseous pollutants during thermal disposal processes.
The process of cement kiln pre-decomposition and steel kiln sintering was simulated by the tube furnace combustion experiment. At 900 ℃, the formation characteristics of gaseous pollutants were studied during the heat utilization and co-combustion process of four typical steel smelting solid wastes, namely, the steel dust sludge, the converter dust, the sintered dust, and the blast furnace bag dust with the waste incineration fly ash. The co-combustion of four kinds of solid wastes of iron and steel smelting, and fly ash of waste incineration was carried out at the mass ratio of 2:8, 3:7 and 4:6, respectively. The results showed that the best blend ratios of the steel dust sludge, the converter dust, the sintered dust, and the blast furnace bag dust with the waste incineration fly ash to inhibit the formation of NO and the volatilization of Pb and Zn were 20%, 20%, 30%, and 40%, respectively. Among the four typical steel smelting solid wastes, the co-combustion of converter ash and waste incineration fly ash has the best inhibition effect on NO formation, the co-combustion of blast furnace bag ash and waste incineration fly ash has the most stable inhibition effect on Pb volatilization, and the best inhibition effect on Zn volatilization. Above experimental works are expected to be a scientific theoretical reference for the further technological development on the formation inhibition and emission control of gaseous pollutants during thermal disposal processes.
2023, 41(12): 206-212,130.
doi: 10.13205/j.hjgc.202312025
Abstract:
In this paper, municipal solid waste incineration (MSWI) fly ash was pre-treated with acid pickling to remove most chloride, and then burned ceramics in conjunction with construction waste. The effects of dechlorinated fly ash doping ratios and sintering temperatures on the morphology and mechanical properties of ceramics were investigated. The doping ratios of the dechlorinated fly ash brought about the content differences of SiO2, Al2O3 and CaO in the mixture. The sintering temperatures mainly affected the pore structure and crystalline phase of ceramics. The results showed that at the dechlorinated fly ash doping of 20% and the sintering temperature of 1150 ℃, the ceramics had the optimal performance: the compressive strength was 7.94 MPa, the particle density was 1245.50 kg/m3, 1 hour water absorption rate was 7.92%. After pretreatment and sintering, compared to the mixture, the leaching rate of heavy metal in the ceramics was reduced by more than 62.50%, and the toxic equivalent concentration of dioxin was reduced by 90.15%. The study provided a reference for the harmless resource treatment of fly ash and construction waste.
In this paper, municipal solid waste incineration (MSWI) fly ash was pre-treated with acid pickling to remove most chloride, and then burned ceramics in conjunction with construction waste. The effects of dechlorinated fly ash doping ratios and sintering temperatures on the morphology and mechanical properties of ceramics were investigated. The doping ratios of the dechlorinated fly ash brought about the content differences of SiO2, Al2O3 and CaO in the mixture. The sintering temperatures mainly affected the pore structure and crystalline phase of ceramics. The results showed that at the dechlorinated fly ash doping of 20% and the sintering temperature of 1150 ℃, the ceramics had the optimal performance: the compressive strength was 7.94 MPa, the particle density was 1245.50 kg/m3, 1 hour water absorption rate was 7.92%. After pretreatment and sintering, compared to the mixture, the leaching rate of heavy metal in the ceramics was reduced by more than 62.50%, and the toxic equivalent concentration of dioxin was reduced by 90.15%. The study provided a reference for the harmless resource treatment of fly ash and construction waste.
2023, 41(12): 213-220,189.
doi: 10.13205/j.hjgc.202312026
Abstract:
In this study, fly ash-slag-based cementitious materials were prepared from fly ash co-metallurgical solid wastes (blast furnace slag, steel slag, and desulfurization gypsum) instead of cement, as backfilling materials for the mining area, and the effect of fly ash incorporation on the hydration mechanism and heavy metal stabilization effect of the cementitious system was investigated. The results showed that a low amount of fly ash (10%) in the cementitious system would inhibit the generation of hydration products in the early stage (within 3 days) of the system and reduce the compressive strength of the cured body; the alkali excitation effect of fly ash would promote the generation of hydration products, calcium alumina to a certain extent, with a facilitating effect on the compressive strength of the cured body at the end of maintenance (the 28 th day); high amount of fly ash in the cementing system (25%) would seriously inhibit the hydration process of the cementing system, but the compressive strength of the product was still higher than the requirements of the cementing material for mining area. On the other hand, the fly ash-slag-based cementitious system stabilized the heavy metals in the fly ash well, and the leaching of heavy metals in all other treatment groups (with fly ash addition of 0%~20%) satisfied the standard limits, except for the Zn in the treatment group with fly ash admixture of 25%, which was close to the China national standard limit of cementitious sand (GB/T 30810—2014). Therefore, using fly ash as mine backfilling cementitious material is an ideal method,under the appropriate admixture amount.
In this study, fly ash-slag-based cementitious materials were prepared from fly ash co-metallurgical solid wastes (blast furnace slag, steel slag, and desulfurization gypsum) instead of cement, as backfilling materials for the mining area, and the effect of fly ash incorporation on the hydration mechanism and heavy metal stabilization effect of the cementitious system was investigated. The results showed that a low amount of fly ash (10%) in the cementitious system would inhibit the generation of hydration products in the early stage (within 3 days) of the system and reduce the compressive strength of the cured body; the alkali excitation effect of fly ash would promote the generation of hydration products, calcium alumina to a certain extent, with a facilitating effect on the compressive strength of the cured body at the end of maintenance (the 28 th day); high amount of fly ash in the cementing system (25%) would seriously inhibit the hydration process of the cementing system, but the compressive strength of the product was still higher than the requirements of the cementing material for mining area. On the other hand, the fly ash-slag-based cementitious system stabilized the heavy metals in the fly ash well, and the leaching of heavy metals in all other treatment groups (with fly ash addition of 0%~20%) satisfied the standard limits, except for the Zn in the treatment group with fly ash admixture of 25%, which was close to the China national standard limit of cementitious sand (GB/T 30810—2014). Therefore, using fly ash as mine backfilling cementitious material is an ideal method,under the appropriate admixture amount.
2023, 41(12): 221-226,287.
doi: 10.13205/j.hjgc.202312027
Abstract:
To explore the effect of straw and fly ash on the accumulation of heavy metals in ryegrass in coal gangue contaminated soil, a pot experiment was conducted to add fly ash (CS1), straw (CS2), and the mixture of fly ash and straw (CS3) into the coal gangue contaminated soil, and the blank was set as the control group. The contents of heavy metal elements Fe, Mn, Cu, Zn, Pb and Cd in ryegrass in each treatment group were analyzed, and the ability of ryegrass to accumulate and migrate heavy metals was evaluated by plant enrichment coefficient and transport coefficient. The results showed that the enrichment ability of ryegrass to heavy metals in each treatment group was quite different. In the single remediation system, fly ash was conducive to the enrichment of Fe and Cd in the aboveground and lower parts of ryegrass. Straw had more potential to promote the absorption and enrichment of Fe, Mn, and Pb in the aboveground and lower parts of ryegrass. Both fly ash and straw inhibited the absorption and enrichment of Zn in the aboveground and lower parts of ryegrass. In the mixed treatment of fly ash and straw, the enrichment ability of Fe and Mn in the upper and lower parts of ryegrass was the best. The enrichment ability of ryegrass roots to Fe, Mn, Cu, Zn, Pb and Cd was greater than that of ryegrass aboveground parts. In summary, fly ash, straw, and their mixture had different degrees of promoting effect on absorption and enrichment of Fe, Mn, Cu, Pb, and Cd in the aboveground and lower parts of ryegrass. It has greater repairing potential for Fe and Mn.
To explore the effect of straw and fly ash on the accumulation of heavy metals in ryegrass in coal gangue contaminated soil, a pot experiment was conducted to add fly ash (CS1), straw (CS2), and the mixture of fly ash and straw (CS3) into the coal gangue contaminated soil, and the blank was set as the control group. The contents of heavy metal elements Fe, Mn, Cu, Zn, Pb and Cd in ryegrass in each treatment group were analyzed, and the ability of ryegrass to accumulate and migrate heavy metals was evaluated by plant enrichment coefficient and transport coefficient. The results showed that the enrichment ability of ryegrass to heavy metals in each treatment group was quite different. In the single remediation system, fly ash was conducive to the enrichment of Fe and Cd in the aboveground and lower parts of ryegrass. Straw had more potential to promote the absorption and enrichment of Fe, Mn, and Pb in the aboveground and lower parts of ryegrass. Both fly ash and straw inhibited the absorption and enrichment of Zn in the aboveground and lower parts of ryegrass. In the mixed treatment of fly ash and straw, the enrichment ability of Fe and Mn in the upper and lower parts of ryegrass was the best. The enrichment ability of ryegrass roots to Fe, Mn, Cu, Zn, Pb and Cd was greater than that of ryegrass aboveground parts. In summary, fly ash, straw, and their mixture had different degrees of promoting effect on absorption and enrichment of Fe, Mn, Cu, Pb, and Cd in the aboveground and lower parts of ryegrass. It has greater repairing potential for Fe and Mn.
2023, 41(12): 227-235.
doi: 10.13205/j.hjgc.202312028
Abstract:
The groundwater pollution problem has become one of the hot and difficult issues of government and public concern in recent years. Groundwater environmental investigation is the basic work of groundwater pollution prevention and control, and it is of great significance to support groundwater environmental supervision. However, in the process of the practical investigation, we often encounter different views on some key issues among practitioners with different professional backgrounds. The existing technical specifications are not suitable for sites with special conditions, such as low permeability soils, and no specific well construction requirements have been stipulated for monitoring wells with different purposes, which is not conducive to the actual investigation work. In this paper, by reviewing global literature and technical specifications, the differences between the objectives of groundwater environmental investigation and traditional hydrogeological investigation were compared and analyzed, and the construction depth and diameter parameters of different monitoring wells were proposed accordingly. The construction depth of monitoring wells for groundwater environmental investigation should be determined by considering the distribution of pollution sources and properties of soil layers, drilling to but not through the underlying aquifuge. Specialized pipe diameters and borehole diameters should be designed for temporary monitoring wells, long-term monitoring wells, and polluted groundwater extraction wells, respectively. Monitoring wells building and flushing, and on-site hydrogeological tests in low permeability soil layers were also introduced based on practical experience and engineering cases. This paper can provide reference and guidance for relevant practitioners in the field of groundwater environmental investigation.
The groundwater pollution problem has become one of the hot and difficult issues of government and public concern in recent years. Groundwater environmental investigation is the basic work of groundwater pollution prevention and control, and it is of great significance to support groundwater environmental supervision. However, in the process of the practical investigation, we often encounter different views on some key issues among practitioners with different professional backgrounds. The existing technical specifications are not suitable for sites with special conditions, such as low permeability soils, and no specific well construction requirements have been stipulated for monitoring wells with different purposes, which is not conducive to the actual investigation work. In this paper, by reviewing global literature and technical specifications, the differences between the objectives of groundwater environmental investigation and traditional hydrogeological investigation were compared and analyzed, and the construction depth and diameter parameters of different monitoring wells were proposed accordingly. The construction depth of monitoring wells for groundwater environmental investigation should be determined by considering the distribution of pollution sources and properties of soil layers, drilling to but not through the underlying aquifuge. Specialized pipe diameters and borehole diameters should be designed for temporary monitoring wells, long-term monitoring wells, and polluted groundwater extraction wells, respectively. Monitoring wells building and flushing, and on-site hydrogeological tests in low permeability soil layers were also introduced based on practical experience and engineering cases. This paper can provide reference and guidance for relevant practitioners in the field of groundwater environmental investigation.
2023, 41(12): 236-240,328.
doi: 10.13205/j.hjgc.202312029
Abstract:
The popularization and application of the dual membrane technology for reclaimed water reuse are seriously restricted by whether the high salinity and refractory reverse osmosis concentrated water can be treated to meet the emission standard. In this paper, taking an actual project of high alkalinity and high bromine reverse osmosis concentrated brine treatment in an industrial park in Jiangsu Province as an example, the main factors affecting the effluent quality were discussed, and the best process operation parameters were determined. The project operation results showed that the treatment effect of the ozone biochemical coupling system will be affected, when Br- concentration and alkalinity were too high. Properly adding hydrogen peroxide can provide a masking effect on bromine ions and reduce the impact of high-concentration bromine ions on ozone utilization efficiency. When the dosage of hydrogen peroxide was 80 mg/L and the alkalinity was controlled less than 2000 mg/L, the COD removal efficiency of the ozone biochemical coupling system increased from 10% to 46%, and the effluent of the whole system met the emission standard. The treatment of RO-concentrated brine in this project can provide guidance and reference for the treatment of similar wastewater.
The popularization and application of the dual membrane technology for reclaimed water reuse are seriously restricted by whether the high salinity and refractory reverse osmosis concentrated water can be treated to meet the emission standard. In this paper, taking an actual project of high alkalinity and high bromine reverse osmosis concentrated brine treatment in an industrial park in Jiangsu Province as an example, the main factors affecting the effluent quality were discussed, and the best process operation parameters were determined. The project operation results showed that the treatment effect of the ozone biochemical coupling system will be affected, when Br- concentration and alkalinity were too high. Properly adding hydrogen peroxide can provide a masking effect on bromine ions and reduce the impact of high-concentration bromine ions on ozone utilization efficiency. When the dosage of hydrogen peroxide was 80 mg/L and the alkalinity was controlled less than 2000 mg/L, the COD removal efficiency of the ozone biochemical coupling system increased from 10% to 46%, and the effluent of the whole system met the emission standard. The treatment of RO-concentrated brine in this project can provide guidance and reference for the treatment of similar wastewater.
2023, 41(12): 241-246,318.
doi: 10.13205/j.hjgc.202312030
Abstract:
For the iron and steel production process, a smart dust control platform combining the characteristics of organization and production management is realized. Based on industrial internet, a two-level management system of production field monitoring and production scheduling is established in the platform. This platform collects data from the iron and steel production process, the working conditions of the non-craft dust removal field, running parameters, and energy consumption. Then the data are analyzed and processed with the method of artificial intelligence to realize the functions of production field management, energy consumption analytics and optimization, process monitoring, and safe warning based on smart image recognition. Safe encryption technology is applied in the platform to admit office personal computers and mobile terminals to get access to the real-time producing and smart warning information from the platform. The platform complies with the third grade of the China National Standard of Intelligent Manufacturing Capability Maturity (GB/T 39117—2020). The real application of the platform shows that the platform can reduce the accident checking and repairing time by 15.29%, improve the total producing efficiency per ton of steel by 37.84%, and decrease the electrical energy consumption per ton of steel by 11.43%.
For the iron and steel production process, a smart dust control platform combining the characteristics of organization and production management is realized. Based on industrial internet, a two-level management system of production field monitoring and production scheduling is established in the platform. This platform collects data from the iron and steel production process, the working conditions of the non-craft dust removal field, running parameters, and energy consumption. Then the data are analyzed and processed with the method of artificial intelligence to realize the functions of production field management, energy consumption analytics and optimization, process monitoring, and safe warning based on smart image recognition. Safe encryption technology is applied in the platform to admit office personal computers and mobile terminals to get access to the real-time producing and smart warning information from the platform. The platform complies with the third grade of the China National Standard of Intelligent Manufacturing Capability Maturity (GB/T 39117—2020). The real application of the platform shows that the platform can reduce the accident checking and repairing time by 15.29%, improve the total producing efficiency per ton of steel by 37.84%, and decrease the electrical energy consumption per ton of steel by 11.43%.
2023, 41(12): 247-255.
doi: 10.13205/j.hjgc.202312031
Abstract:
The resuspension of sediment caused by wind waves will directly affect the lighting condition of lake water, promote the release of pollutants in sediment, and have a big impact on the construction of the lake ecosystem. In this paper, the published data validation was used to verify the adaptability of the empirical calculation formula of wind wave elements and wind wave shear stress in shallow lakes. Based on the simplified model and the wind-induced resuspension impact assessment method, the impact of wind waves on the ecological restoration of the Jinhu Lake water was studied. By comprehensive measures, such as ecological enclosure, comprehensive substrate improvers, and composite microbial agents, 1.5 million m2 of submerged plants were successfully restored. This method can be used to assess the impact of wind and waves on sediment resuspension in shallow lakes, and guide the design of water ecological restoration and endogenous pollution control projects in shallow lakes.
The resuspension of sediment caused by wind waves will directly affect the lighting condition of lake water, promote the release of pollutants in sediment, and have a big impact on the construction of the lake ecosystem. In this paper, the published data validation was used to verify the adaptability of the empirical calculation formula of wind wave elements and wind wave shear stress in shallow lakes. Based on the simplified model and the wind-induced resuspension impact assessment method, the impact of wind waves on the ecological restoration of the Jinhu Lake water was studied. By comprehensive measures, such as ecological enclosure, comprehensive substrate improvers, and composite microbial agents, 1.5 million m2 of submerged plants were successfully restored. This method can be used to assess the impact of wind and waves on sediment resuspension in shallow lakes, and guide the design of water ecological restoration and endogenous pollution control projects in shallow lakes.
2023, 41(12): 256-263,295.
doi: 10.13205/j.hjgc.202312032
Abstract:
At present, large-scale environmental NIMBY facilities have been strongly resisted by the public due to their potential environmental pollution. Considering the correlation between factors influencing NIMBY facility location and residents' rejection of NIMBY facilities in terms of spatial distance, a two-stage location optimal model was constructed based on GIS and multi-objective decision-making theory. In the first stage, a comprehensive evaluation index system including geographic information factors was established, and the influence relationship between indicators was determined by the DEMATEL method to calculate the weight of the indicators. Then, GIS technology was used to superimpose geographical layers to obtain alternative areas. In the second stage, the concept of a multi-valued neutrosophic set was introduced to evaluate the alternative areas, and the expert weight calculation method based on the deviation measure was proposed. The interactive multi-criteria decision method (TODIM) based on the prospect theory was extended to the probabilistic multi-valued intelligent cluster decision-making environment, and then the candidate regions were ranked. Finally, a waste-to-energy project in Beijing was taken as an example, to verify the feasibility and reliability of the model, which provides a powerful reference for the decision-making of large-scale environmental NIMBY facilities in urban planning and layout.
At present, large-scale environmental NIMBY facilities have been strongly resisted by the public due to their potential environmental pollution. Considering the correlation between factors influencing NIMBY facility location and residents' rejection of NIMBY facilities in terms of spatial distance, a two-stage location optimal model was constructed based on GIS and multi-objective decision-making theory. In the first stage, a comprehensive evaluation index system including geographic information factors was established, and the influence relationship between indicators was determined by the DEMATEL method to calculate the weight of the indicators. Then, GIS technology was used to superimpose geographical layers to obtain alternative areas. In the second stage, the concept of a multi-valued neutrosophic set was introduced to evaluate the alternative areas, and the expert weight calculation method based on the deviation measure was proposed. The interactive multi-criteria decision method (TODIM) based on the prospect theory was extended to the probabilistic multi-valued intelligent cluster decision-making environment, and then the candidate regions were ranked. Finally, a waste-to-energy project in Beijing was taken as an example, to verify the feasibility and reliability of the model, which provides a powerful reference for the decision-making of large-scale environmental NIMBY facilities in urban planning and layout.
2023, 41(12): 264-269,311.
doi: 10.13205/j.hjgc.202312033
Abstract:
In order to accurately evaluate the difference between poor Class V water quality and similar water quality, the water quality identification index method was introduced to evaluate the groundwater quality of typical informal landfill. The results showed that the single factor water quality evaluation results of ammonia nitrogen, permanganate index and chloride index were from 66.362 to 255.3251, 13.89 to 40.036 and 15.111 to 21.417, respectively, due to the direct contact between shallow groundwater and domestic garbage leachate. The comprehensive evaluation results of groundwater quality at each monitoring point are 9.645~25.9521, all of which are inferior category V. The lowest values were found in the pre-2005 landfill area. Due to the effective barrier effect of the water barrier layer on the pollutants, the water quality of the micro-confined water is significantly better than that of the diving layer, and the comprehensive evaluation results of groundwater quality at each monitoring point are 3.100~3.700. From the spatial distribution characteristics, there are significant differences in the single factor water quality evaluation results of submersible or microconfined water in different landfills. There are significant differences in the comprehensive evaluation results of diving water quality in different landfill areas, but there is no significant difference in the comprehensive evaluation results of microconfined water. The research results can be used as reference for groundwater quality assessment and environmental management of landfill sites in China.
In order to accurately evaluate the difference between poor Class V water quality and similar water quality, the water quality identification index method was introduced to evaluate the groundwater quality of typical informal landfill. The results showed that the single factor water quality evaluation results of ammonia nitrogen, permanganate index and chloride index were from 66.362 to 255.3251, 13.89 to 40.036 and 15.111 to 21.417, respectively, due to the direct contact between shallow groundwater and domestic garbage leachate. The comprehensive evaluation results of groundwater quality at each monitoring point are 9.645~25.9521, all of which are inferior category V. The lowest values were found in the pre-2005 landfill area. Due to the effective barrier effect of the water barrier layer on the pollutants, the water quality of the micro-confined water is significantly better than that of the diving layer, and the comprehensive evaluation results of groundwater quality at each monitoring point are 3.100~3.700. From the spatial distribution characteristics, there are significant differences in the single factor water quality evaluation results of submersible or microconfined water in different landfills. There are significant differences in the comprehensive evaluation results of diving water quality in different landfill areas, but there is no significant difference in the comprehensive evaluation results of microconfined water. The research results can be used as reference for groundwater quality assessment and environmental management of landfill sites in China.
2023, 41(12): 270-277.
doi: 10.13205/j.hjgc.202312034
Abstract:
Aiming at the high subjectivity of the traditional DRASTIC model in the process of the parameter weight determination, taking shallow groundwater in a certain area in northern Guangdong Province as a study target, the BP neural network was optimized and the DRASTICL model was constructed by using the collected shallow groundwater-related data and adding land use type parameter. On this basis, groundwater NO3- concentration was used to verify the models, and further the BP neural network and the constructed DRASTICL model were coupled to establish a BP-DRASTICL model. Finally, risk control strategies were suggested according to the spatial distribution characteristics of groundwater vulnerability. The results showed that when the training function was trainlm, the learning rate was 0.1, and the number of hidden layer neurons was 6, BP neural network performed best, and accordingly the optimal BP-DRASTICL parameter weights were 0.1420 (groundwater depth, D), 0.1151 (recharge, R), 0.0791 (aquifer media, A), 0.1833 (soil medium, S), 0.0908 (topography, T), 0.1574 (influence of vadose zone media, I), 0.0891 (hydraulic conductivity, C) and 0.1433 (land use type, L). D, S, T and L had the greatest influence on the evaluation results. Compared with the DRASTIC models and the DRASTICL model, the BP-DRASTICL model had the highest Pearson (0.615) and Spearman (0.656) correlation coefficients, indicating a high linear correlation between the actual nitrate concentration and the vulnerability index. The groundwater vulnerability was generally in the extremely low, and low level, across the study area, and the areas with the high and extremely high vulnerability level were mainly distributed in the middle of the study area. According to the spatial distribution characteristics of the vulnerability, differentiated strategies were proposed for groundwater pollution risk control. Using the BP neural network to determine the parameter weights of the DRASTICL model is more accurate than using the traditional expert scoring method, because it reduces the influence of human subjectivity.
Aiming at the high subjectivity of the traditional DRASTIC model in the process of the parameter weight determination, taking shallow groundwater in a certain area in northern Guangdong Province as a study target, the BP neural network was optimized and the DRASTICL model was constructed by using the collected shallow groundwater-related data and adding land use type parameter. On this basis, groundwater NO3- concentration was used to verify the models, and further the BP neural network and the constructed DRASTICL model were coupled to establish a BP-DRASTICL model. Finally, risk control strategies were suggested according to the spatial distribution characteristics of groundwater vulnerability. The results showed that when the training function was trainlm, the learning rate was 0.1, and the number of hidden layer neurons was 6, BP neural network performed best, and accordingly the optimal BP-DRASTICL parameter weights were 0.1420 (groundwater depth, D), 0.1151 (recharge, R), 0.0791 (aquifer media, A), 0.1833 (soil medium, S), 0.0908 (topography, T), 0.1574 (influence of vadose zone media, I), 0.0891 (hydraulic conductivity, C) and 0.1433 (land use type, L). D, S, T and L had the greatest influence on the evaluation results. Compared with the DRASTIC models and the DRASTICL model, the BP-DRASTICL model had the highest Pearson (0.615) and Spearman (0.656) correlation coefficients, indicating a high linear correlation between the actual nitrate concentration and the vulnerability index. The groundwater vulnerability was generally in the extremely low, and low level, across the study area, and the areas with the high and extremely high vulnerability level were mainly distributed in the middle of the study area. According to the spatial distribution characteristics of the vulnerability, differentiated strategies were proposed for groundwater pollution risk control. Using the BP neural network to determine the parameter weights of the DRASTICL model is more accurate than using the traditional expert scoring method, because it reduces the influence of human subjectivity.
2023, 41(12): 278-287.
doi: 10.13205/j.hjgc.202312035
Abstract:
Tangshan as a heavy industry city, its air pollution is easy to affect the local and Beijing-Tianjin-Hebei region ecological environment.In order to study the pollution degree of heavy metals in atmospheric dust-fall in Tangshan and its health risk to the human body, 23 sampling points were set up to collect dust. The results showed that the average contents of As, Cd, Pb, Cr, Ni, Cu and Zn in the atmospheric dust were 12.89, 1.90, 158.06, 88.00, 33.13, 65.67 and 933.65 mg/kg, respectively. The spatial distribution characteristics showed that the high-value areas of Pb, Ni and Cr were mainly distributed in the northern, central and southeastern parts of Tangshan, As is mainly distributed in the northern and southeastern parts, Cd is mainly distributed in the northwestern and central parts, Zn is mainly distributed in the northeastern parts, and the high-value areas of Cu are scattered. Enrichment factor analysis showed that As, Cr and Ni were mildly enriched, Cu was moderately enriched, Pb was highly enriched, and Cd and Zn were severely enriched. According to the evaluation results of the geo-accumulation index, the pollution degree of Ni, Cr and As elements ranged from no pollution to moderate pollution. The pollution degree of Cu element was moderate. The pollution degree of Pb element was moderate pollution to strong pollution. Cd and Zn elements were in a highly polluted level. For children and adults, the total non-carcinogenic risk (HI) of heavy metals in atmospheric dust was in the sequence of Pb>As>Cr>Zn>Cd>Ni>Cu, and Pb>As>Cr>Cd>Zn>Ni>Cu, respectively. The three exposure routes showed the highest risk of hand-mouth ingestion, medium risk of respiratory, and the lowest risk of skin. The total non-carcinogenic risk (HI) of children was 1.63, which was easy to cause harm to children's health. The total non-carcinogenic risk (HI) in the adult population was 0.223, indicating a small impact on adult health. The carcinogenic risk of Ni, Cr, As and Cd elements were calculated, and their values were all between 10-7 and 10-9, but not more than 10-6 and 10-4, indicating that these four elements had no carcinogenic risk through the respiratory pathway. The source analysis results indicate that Cr, Pb, Cu, Cd, and Ni in the study area may come from the mixed sources of transportation and soil, Zn may mainly come from industrial sources, and As may mainly come from mixed sources of soil and industry.
Tangshan as a heavy industry city, its air pollution is easy to affect the local and Beijing-Tianjin-Hebei region ecological environment.In order to study the pollution degree of heavy metals in atmospheric dust-fall in Tangshan and its health risk to the human body, 23 sampling points were set up to collect dust. The results showed that the average contents of As, Cd, Pb, Cr, Ni, Cu and Zn in the atmospheric dust were 12.89, 1.90, 158.06, 88.00, 33.13, 65.67 and 933.65 mg/kg, respectively. The spatial distribution characteristics showed that the high-value areas of Pb, Ni and Cr were mainly distributed in the northern, central and southeastern parts of Tangshan, As is mainly distributed in the northern and southeastern parts, Cd is mainly distributed in the northwestern and central parts, Zn is mainly distributed in the northeastern parts, and the high-value areas of Cu are scattered. Enrichment factor analysis showed that As, Cr and Ni were mildly enriched, Cu was moderately enriched, Pb was highly enriched, and Cd and Zn were severely enriched. According to the evaluation results of the geo-accumulation index, the pollution degree of Ni, Cr and As elements ranged from no pollution to moderate pollution. The pollution degree of Cu element was moderate. The pollution degree of Pb element was moderate pollution to strong pollution. Cd and Zn elements were in a highly polluted level. For children and adults, the total non-carcinogenic risk (HI) of heavy metals in atmospheric dust was in the sequence of Pb>As>Cr>Zn>Cd>Ni>Cu, and Pb>As>Cr>Cd>Zn>Ni>Cu, respectively. The three exposure routes showed the highest risk of hand-mouth ingestion, medium risk of respiratory, and the lowest risk of skin. The total non-carcinogenic risk (HI) of children was 1.63, which was easy to cause harm to children's health. The total non-carcinogenic risk (HI) in the adult population was 0.223, indicating a small impact on adult health. The carcinogenic risk of Ni, Cr, As and Cd elements were calculated, and their values were all between 10-7 and 10-9, but not more than 10-6 and 10-4, indicating that these four elements had no carcinogenic risk through the respiratory pathway. The source analysis results indicate that Cr, Pb, Cu, Cd, and Ni in the study area may come from the mixed sources of transportation and soil, Zn may mainly come from industrial sources, and As may mainly come from mixed sources of soil and industry.
2023, 41(12): 288-295.
doi: 10.13205/j.hjgc.202312036
Abstract:
As the national and regional ecological security bottom line, the ecological redline can provide a scientific basis for ecological redline supervision and optimization adjustment by conducting research on human interference risk and its driving factors. This paper took Taizhou Ecological Redline Area as the research area and constructed a human interference risk assessment method based on the Bayesian network. We expressed the risk through human interference risk (risk source), ecological redline sensitivity (risk receptor), human interference accessibility (action path), and human interference risk (risk assessment result), compared and analyzed the changing trend of human activity interference risk of different human interference risk sources (building development, traffic construction, mineral mining, etc.) to the ecological redline area in 2018 and 2020. According to the tool of Sensitivity to Findings in Netica software, the main driving factors of human activities disturbing the spatial-temporal evolution of risk were explored. The results showed that: 1) compared with 2018, the risk of human interference in Taizhou decreased in 2020; 2) in 2018 and 2020, the human interference risk in Gaogang District of Taizhou was the highest, and its should be enhanced supervision and prevention; 3) the main driving factor of ecological redline is the proportion of human activity area and population density indicators. The research can provide a decision-making reference for the optimization and adjustment of ecological redline, early warning and prevention and control of human activity interference risk.
As the national and regional ecological security bottom line, the ecological redline can provide a scientific basis for ecological redline supervision and optimization adjustment by conducting research on human interference risk and its driving factors. This paper took Taizhou Ecological Redline Area as the research area and constructed a human interference risk assessment method based on the Bayesian network. We expressed the risk through human interference risk (risk source), ecological redline sensitivity (risk receptor), human interference accessibility (action path), and human interference risk (risk assessment result), compared and analyzed the changing trend of human activity interference risk of different human interference risk sources (building development, traffic construction, mineral mining, etc.) to the ecological redline area in 2018 and 2020. According to the tool of Sensitivity to Findings in Netica software, the main driving factors of human activities disturbing the spatial-temporal evolution of risk were explored. The results showed that: 1) compared with 2018, the risk of human interference in Taizhou decreased in 2020; 2) in 2018 and 2020, the human interference risk in Gaogang District of Taizhou was the highest, and its should be enhanced supervision and prevention; 3) the main driving factor of ecological redline is the proportion of human activity area and population density indicators. The research can provide a decision-making reference for the optimization and adjustment of ecological redline, early warning and prevention and control of human activity interference risk.
2023, 41(12): 296-303.
doi: 10.13205/j.hjgc.202312037
Abstract:
Accurately describing the spatial distribution of soil heavy metals and reasonably dividing soil pollution risk areas is an important prerequisite for soil heavy metal pollution risk control. In this paper, an industrialized area in Guangdong Province was taken as the study area. Based on random forest (RF) and fuzzy-c-means (FCM), the soil heavy metal data of 577 sampling points and 12 environmental covariate data were used to analyze the soil Cr, Pb, Cu and Zn concentrations. The prediction models of soil heavy metal concentrations were constructed, the data-driven regional soil heavy metal pollution risk classification was carried out, and the corresponding risk classification control strategy was proposed. The results showed that the measured concentrations of Cr, Pb, Cu and Zn were 4.00 to 885.60, 9.39 to 2588.11, 2.20 to 475.00 and 11.05 to 8162.42 mg/kg, respectively. Except for Pb concentration, the average values of Cr, Cu and Zn concentrations were 1.10~1.29 times higher than the local soil background values. The variation coefficients of the four heavy metals were between 86% and 319%, which belonged to the variation level of medium or upper intensity. Soil heavy metals were greatly affected by human activities. The random forest had a good prediction performance when the number of node variables (mtry) was 5 and the number of decision trees (ntree) was 800. The maximum values of R2 were 0.78, 0.79, 0.85 and 0.76, respectively, and the minimum values of RMSE were 21.57, 59.88, 62.38 and 105.88, respectively. The high-value areas of Cr were mostly located in the northeastern and north-central of the study area, while the high-value areas of Pb, Cu and Zn were concentrated in the north-central and south-central parts. In the development of soil heavy metal pollution risk control strategies, priority should be given to the central region. The study area was divided into two risk areas, of which, area A was a high-risk area, and the risk control of heavy metal pollution should be strictly carried out. Area B was a low-risk area. It is also necessary to strengthen monitoring and early warning and take source control measures to prevent new pollution.
Accurately describing the spatial distribution of soil heavy metals and reasonably dividing soil pollution risk areas is an important prerequisite for soil heavy metal pollution risk control. In this paper, an industrialized area in Guangdong Province was taken as the study area. Based on random forest (RF) and fuzzy-c-means (FCM), the soil heavy metal data of 577 sampling points and 12 environmental covariate data were used to analyze the soil Cr, Pb, Cu and Zn concentrations. The prediction models of soil heavy metal concentrations were constructed, the data-driven regional soil heavy metal pollution risk classification was carried out, and the corresponding risk classification control strategy was proposed. The results showed that the measured concentrations of Cr, Pb, Cu and Zn were 4.00 to 885.60, 9.39 to 2588.11, 2.20 to 475.00 and 11.05 to 8162.42 mg/kg, respectively. Except for Pb concentration, the average values of Cr, Cu and Zn concentrations were 1.10~1.29 times higher than the local soil background values. The variation coefficients of the four heavy metals were between 86% and 319%, which belonged to the variation level of medium or upper intensity. Soil heavy metals were greatly affected by human activities. The random forest had a good prediction performance when the number of node variables (mtry) was 5 and the number of decision trees (ntree) was 800. The maximum values of R2 were 0.78, 0.79, 0.85 and 0.76, respectively, and the minimum values of RMSE were 21.57, 59.88, 62.38 and 105.88, respectively. The high-value areas of Cr were mostly located in the northeastern and north-central of the study area, while the high-value areas of Pb, Cu and Zn were concentrated in the north-central and south-central parts. In the development of soil heavy metal pollution risk control strategies, priority should be given to the central region. The study area was divided into two risk areas, of which, area A was a high-risk area, and the risk control of heavy metal pollution should be strictly carried out. Area B was a low-risk area. It is also necessary to strengthen monitoring and early warning and take source control measures to prevent new pollution.
2023, 41(12): 304-311.
doi: 10.13205/j.hjgc.202312038
Abstract:
The stabilization effects of heavy metals in municipal solid waste incineration fly ash stabilized by piperazine chelating agent (TS300) and dimethyl dithiocarbamate (SDD) at different dosages were compared. The results showed that the leaching concentrations of heavy metals in chelated fly ash met the standard limit of GB 16889—2008, when the dosage of TS300 and SDD was 3% and 5%, respectively. However, the leaching concentrations of Cd in the 3% TS300 group, and Pb and Cd in the 5% SDD group, all exceeded the standard limit after the chelated fly ash was placed for 28 days. In addition, chelation stabilization treatment can transform heavy metals in fly ash from unstable reducible fractions to more stable oxidizable fractions, and it can also broaden the range of pH value for stable existence of fly ash (the leaching concentrations of heavy metals met the standard within this pH range). The analysis results of the environmental risk assessment code showed that the target heavy metals in the 3% TS300 group posed no risk to the environment within the inspection time range (0 to 28 days), while the Pb, Zn and Cd in the 5% SDD group posed potential environmental risks after being placed for 28 days. Therefore, TS300 is superior to SDD, in terms of heavy metal stabilization effect of fly ash in this study.
The stabilization effects of heavy metals in municipal solid waste incineration fly ash stabilized by piperazine chelating agent (TS300) and dimethyl dithiocarbamate (SDD) at different dosages were compared. The results showed that the leaching concentrations of heavy metals in chelated fly ash met the standard limit of GB 16889—2008, when the dosage of TS300 and SDD was 3% and 5%, respectively. However, the leaching concentrations of Cd in the 3% TS300 group, and Pb and Cd in the 5% SDD group, all exceeded the standard limit after the chelated fly ash was placed for 28 days. In addition, chelation stabilization treatment can transform heavy metals in fly ash from unstable reducible fractions to more stable oxidizable fractions, and it can also broaden the range of pH value for stable existence of fly ash (the leaching concentrations of heavy metals met the standard within this pH range). The analysis results of the environmental risk assessment code showed that the target heavy metals in the 3% TS300 group posed no risk to the environment within the inspection time range (0 to 28 days), while the Pb, Zn and Cd in the 5% SDD group posed potential environmental risks after being placed for 28 days. Therefore, TS300 is superior to SDD, in terms of heavy metal stabilization effect of fly ash in this study.
2023, 41(12): 312-318.
doi: 10.13205/j.hjgc.202312039
Abstract:
Climate change is one of the most challenging issues today, and the scale of international tourism reaches more than one trillion US dollars, which also has a significant impact on the environment. Tourism energy consumption and carbon emissions have also become one of the important factors affecting global climate change. Based on the original data of the tourism industry in Wuyishan, this paper analyzes the current tourism situation, such as tourist flow, source, and mode of transportation, divides the tourism activities into four parts: transportation, accommodation, catering, and entertainment, calculates the tourism carbon footprint of Wuyishan in 2019 and 2020 using the bottom-up method, and compares it with the research results on other regions. The results showed that the carbon footprint in 2019 was 873000 tons, with a per capita carbon footprint of 53.7 kg/person; the carbon footprint in 2020 was 467000 tons, with a per capita carbon footprint of 43.3 kg/person. The carbon footprint proportion of transportation, accommodation, catering, and entertainment was approximately 14:4:1:1. The main reason for the reduction in carbon footprint is the reduction in transportation emissions. In 2020, the carbon emissions of tourism transportation (315000 tons) were nearly double that of 2019 (620000 tons). The tourism carbon footprint of Wuyishan is at a lower level nationwide. In the future, we should focus on carbon emission reduction in the field of tourism and transportation.
Climate change is one of the most challenging issues today, and the scale of international tourism reaches more than one trillion US dollars, which also has a significant impact on the environment. Tourism energy consumption and carbon emissions have also become one of the important factors affecting global climate change. Based on the original data of the tourism industry in Wuyishan, this paper analyzes the current tourism situation, such as tourist flow, source, and mode of transportation, divides the tourism activities into four parts: transportation, accommodation, catering, and entertainment, calculates the tourism carbon footprint of Wuyishan in 2019 and 2020 using the bottom-up method, and compares it with the research results on other regions. The results showed that the carbon footprint in 2019 was 873000 tons, with a per capita carbon footprint of 53.7 kg/person; the carbon footprint in 2020 was 467000 tons, with a per capita carbon footprint of 43.3 kg/person. The carbon footprint proportion of transportation, accommodation, catering, and entertainment was approximately 14:4:1:1. The main reason for the reduction in carbon footprint is the reduction in transportation emissions. In 2020, the carbon emissions of tourism transportation (315000 tons) were nearly double that of 2019 (620000 tons). The tourism carbon footprint of Wuyishan is at a lower level nationwide. In the future, we should focus on carbon emission reduction in the field of tourism and transportation.
2023, 41(12): 319-328.
doi: 10.13205/j.hjgc.202312040
Abstract:
At present, coal gasification slag (CGS) has not been effectively utilized, and it is still mainly piled or landfilled. With the increase in CGS accumulation, the problems of resource waste and environmental pollution become more and more prominent. Therefore, it is urgent to find an efficient and reasonable utilization method for CGS. The formation process of CGS is introduced. The status quo of CGS applied in building materials, soil improvement, adsorption materials, utilization of residual carbon and catalyst carrier are reviewed. Among them, building materials are combed into three parts: cementitious materials, brick wall materials and ceramsite. The review of adsorption materials includes wastewater treatment and CO2 adsorption. Utilization of residual carbon includes blending burning, catalytic graphitization, and electromagnetic wave absorption. Finally, a proposal for comprehensive CGS utilization is put forward. The residual carbon can be used separately from the ash residue. The residual carbon can be used as the raw material of activated carbon and electromagnetic wave absorber. The utilization of ash can be divided into two categories based on the heavy metal content in the leaching solution: if the toxicity exceeds the standard, the ceramic particles can be produced by the non-burning method; if the toxicity does not exceed the standard, they can be used to make zeolite or as an additive for cementitious materials according to their composition.
At present, coal gasification slag (CGS) has not been effectively utilized, and it is still mainly piled or landfilled. With the increase in CGS accumulation, the problems of resource waste and environmental pollution become more and more prominent. Therefore, it is urgent to find an efficient and reasonable utilization method for CGS. The formation process of CGS is introduced. The status quo of CGS applied in building materials, soil improvement, adsorption materials, utilization of residual carbon and catalyst carrier are reviewed. Among them, building materials are combed into three parts: cementitious materials, brick wall materials and ceramsite. The review of adsorption materials includes wastewater treatment and CO2 adsorption. Utilization of residual carbon includes blending burning, catalytic graphitization, and electromagnetic wave absorption. Finally, a proposal for comprehensive CGS utilization is put forward. The residual carbon can be used separately from the ash residue. The residual carbon can be used as the raw material of activated carbon and electromagnetic wave absorber. The utilization of ash can be divided into two categories based on the heavy metal content in the leaching solution: if the toxicity exceeds the standard, the ceramic particles can be produced by the non-burning method; if the toxicity does not exceed the standard, they can be used to make zeolite or as an additive for cementitious materials according to their composition.
2023, 41(12): 329-336,342.
doi: 10.13205/j.hjgc.202312041
Abstract:
The remediation of contaminated soil is an important way for human beings to improve the quality of the ecological environment, which has attracted more and more attention. In this study, the relevant literature on global soil remediation in the past ten years (2011 to 2020) was analyzed using the software of CiteSpace and VOSviewer as the bibliometric tool based on the literature data source of the Web of Science database, and the global research status and future development trend were also discussed. The results showed that the number of publications on contaminated soil remediation grew rapidly over the study period. The five countries with the most published papers included China, the United States, Australia, Germany, and France. The main journals that published foreign literature included Environmental Science and Pollution Research, Chemosphere, Science of the Total Environment, etc. In terms of the number and the cited frequency of publications for foreign literature, Chinese scientific research institutions occupied an important position, indicating that China had a strong international academic influence in contaminated soil remediation. Through the analysis of keywords occurrence, it was found that heavy metals, bioavailability, lead, phytoremediation, bioremediation, immobilization, risk assessment and polycyclic aromatic hydrocarbons were the main focuses of the research in recent ten years. Using the highlighting key statistics functions, it was found that risk assessment, the spatial distribution of pollution factors, soil microbial community and biochar were gradually becoming the new research hotspots in the world. Finally, some suggestions for the key research directions in future were given combined with the author's engineering experience in soil remediation.
The remediation of contaminated soil is an important way for human beings to improve the quality of the ecological environment, which has attracted more and more attention. In this study, the relevant literature on global soil remediation in the past ten years (2011 to 2020) was analyzed using the software of CiteSpace and VOSviewer as the bibliometric tool based on the literature data source of the Web of Science database, and the global research status and future development trend were also discussed. The results showed that the number of publications on contaminated soil remediation grew rapidly over the study period. The five countries with the most published papers included China, the United States, Australia, Germany, and France. The main journals that published foreign literature included Environmental Science and Pollution Research, Chemosphere, Science of the Total Environment, etc. In terms of the number and the cited frequency of publications for foreign literature, Chinese scientific research institutions occupied an important position, indicating that China had a strong international academic influence in contaminated soil remediation. Through the analysis of keywords occurrence, it was found that heavy metals, bioavailability, lead, phytoremediation, bioremediation, immobilization, risk assessment and polycyclic aromatic hydrocarbons were the main focuses of the research in recent ten years. Using the highlighting key statistics functions, it was found that risk assessment, the spatial distribution of pollution factors, soil microbial community and biochar were gradually becoming the new research hotspots in the world. Finally, some suggestions for the key research directions in future were given combined with the author's engineering experience in soil remediation.
2023, 41(12): 337-342.
doi: 10.13205/j.hjgc.202312042
Abstract:
Artificial fishing reefs can provide breeding, growth, feeding, and shelter for fish and other species, and are of great significance for optimizing marine ecology, repairing marine environment, promoting marine ranching, and enhancing marine carbon sinks. Concrete is the most widely used material in the preparation of artificial reefs, but its high preparation cost limits the application of artificial reefs in marine environment restoration. In view of China's long coastline, large demand for artificial reefs, and high preparation cost, and based on the current situation of China's large production of industrial solid waste and low utilization rate of resources, this paper summarized the research status of industrial solid waste based artificial reef concrete represented by fly ash, iron tailings, steel slag, etc., and introduced the preparation methods, performance, and impact on the marine environment of the industrial solid waste based artificial reef. This paper also analyzed the feasibility of the application of industrial solid waste-based artificial reefs, and put forward suggestions for future research direction. It provides a new path for large scale high-value utilization of industrial solid waste, and a reference for promotion and application of low-cost industrial solid waste-based artificial reef concrete.
Artificial fishing reefs can provide breeding, growth, feeding, and shelter for fish and other species, and are of great significance for optimizing marine ecology, repairing marine environment, promoting marine ranching, and enhancing marine carbon sinks. Concrete is the most widely used material in the preparation of artificial reefs, but its high preparation cost limits the application of artificial reefs in marine environment restoration. In view of China's long coastline, large demand for artificial reefs, and high preparation cost, and based on the current situation of China's large production of industrial solid waste and low utilization rate of resources, this paper summarized the research status of industrial solid waste based artificial reef concrete represented by fly ash, iron tailings, steel slag, etc., and introduced the preparation methods, performance, and impact on the marine environment of the industrial solid waste based artificial reef. This paper also analyzed the feasibility of the application of industrial solid waste-based artificial reefs, and put forward suggestions for future research direction. It provides a new path for large scale high-value utilization of industrial solid waste, and a reference for promotion and application of low-cost industrial solid waste-based artificial reef concrete.
