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2020 Vol. 38, No. 9
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2020, 38(9): 1-5.
doi: 10.13205/j.hjgc.202009001
Abstract:
Three-dimensional electrode electro-Fenton method was used to treat phenol-containing wastewater from pottery process. The removal efficiency of phenol and COD was studied with the single factor of pH, time, voltage, FeSO4·7H2O dosage, ventilation, electrolyte dosage and electrode spacing selected and setted at different levels. The electrochemical energy consumption of the method was also discussed. The results showed that under the conditions of pH of 3, voltage of 15V, FeSO4·7H2O dosage of 1.8 g/L, ventilation of 9 L/min, Na2SO4 powder dosage of 1.0 g/L, electrode spacing of 10 cm and reaction time of 120 min, the removal rates of phenol and COD in wastewater could reach 94.13% and 86.67% respectively. The treatment effect was obvious and the energy consumption was much lower than that of two-dimensional electrodes. It could provide reference for practical application.
Three-dimensional electrode electro-Fenton method was used to treat phenol-containing wastewater from pottery process. The removal efficiency of phenol and COD was studied with the single factor of pH, time, voltage, FeSO4·7H2O dosage, ventilation, electrolyte dosage and electrode spacing selected and setted at different levels. The electrochemical energy consumption of the method was also discussed. The results showed that under the conditions of pH of 3, voltage of 15V, FeSO4·7H2O dosage of 1.8 g/L, ventilation of 9 L/min, Na2SO4 powder dosage of 1.0 g/L, electrode spacing of 10 cm and reaction time of 120 min, the removal rates of phenol and COD in wastewater could reach 94.13% and 86.67% respectively. The treatment effect was obvious and the energy consumption was much lower than that of two-dimensional electrodes. It could provide reference for practical application.
2020, 38(9): 6-13,22.
doi: 10.13205/j.hjgc.202009002
Abstract:
Focusing on the spatial distribution characteristics and pollution of nitrogen in the interaction zone of rivers under specific geological and geomorphological control, it is helpful to fully understand the characteristics of river water environment and the causes of pollution. In this paper, the intersection of Zaohe River and Weihe River was taken as the research area, and sampling points were set along the river direction, vertical and horizontal, respectively. The variation characteristics of the distribution of nitrogen in surface water, groundwater and sediments in the interaction zone and their biogeochemistry properties were studied. The results showed that:1) along the river, the concentration of NO3--N in the Zaohe River was lower than that in the Weihe River. The concentration of NO3--N increases after the intersection of the two rivers, while the concentration in the groundwater gradually decreased. Both NO2--N and NH4+-N in surface water and groundwater had a tendency to gradually decrease in river flow direction. In the transverse section, the NO3--N distribution was obviously affected by the groundwater recharge mode of the river. 2) By the space, NO3--N increased with depth, showing a distribution law of increasing first and then decreasing. The NH4+-N began to decrease with depth and then increased. 3) The pH of water was significantly positively correlated with NO3--N, and DO was significantly negatively correlated with NH4+-N. TOC in the sediment showed a significant negative correlation with NO2--N. There was a very significant positive correlation between NO2--N and NH4+-N between the nitrogen.
Focusing on the spatial distribution characteristics and pollution of nitrogen in the interaction zone of rivers under specific geological and geomorphological control, it is helpful to fully understand the characteristics of river water environment and the causes of pollution. In this paper, the intersection of Zaohe River and Weihe River was taken as the research area, and sampling points were set along the river direction, vertical and horizontal, respectively. The variation characteristics of the distribution of nitrogen in surface water, groundwater and sediments in the interaction zone and their biogeochemistry properties were studied. The results showed that:1) along the river, the concentration of NO3--N in the Zaohe River was lower than that in the Weihe River. The concentration of NO3--N increases after the intersection of the two rivers, while the concentration in the groundwater gradually decreased. Both NO2--N and NH4+-N in surface water and groundwater had a tendency to gradually decrease in river flow direction. In the transverse section, the NO3--N distribution was obviously affected by the groundwater recharge mode of the river. 2) By the space, NO3--N increased with depth, showing a distribution law of increasing first and then decreasing. The NH4+-N began to decrease with depth and then increased. 3) The pH of water was significantly positively correlated with NO3--N, and DO was significantly negatively correlated with NH4+-N. TOC in the sediment showed a significant negative correlation with NO2--N. There was a very significant positive correlation between NO2--N and NH4+-N between the nitrogen.
2020, 38(9): 14-22.
doi: 10.13205/j.hjgc.202009003
Abstract:
Nano-zero-valent iron (nZVI) has good adsorption properties and reactivity for heavy metals and halogen-containing organic pollutants, due to its strong reducibility, small particle size and large specific surface area. It has good application prospects in environmental remediation. However, the large-scale application of nZVI is limited by its easy oxidation, agglomeration and low mechanical strength. This paper systematically compared the characteristics of mechanical method, gas condensation method and reduction method in preparing nZVI. It mainly summarized the research progress of surface modification, metal modification, carrier loading and matrix encapsulation, as well as their application in water and soil environmental remediation.
Nano-zero-valent iron (nZVI) has good adsorption properties and reactivity for heavy metals and halogen-containing organic pollutants, due to its strong reducibility, small particle size and large specific surface area. It has good application prospects in environmental remediation. However, the large-scale application of nZVI is limited by its easy oxidation, agglomeration and low mechanical strength. This paper systematically compared the characteristics of mechanical method, gas condensation method and reduction method in preparing nZVI. It mainly summarized the research progress of surface modification, metal modification, carrier loading and matrix encapsulation, as well as their application in water and soil environmental remediation.
2020, 38(9): 23-30,153.
doi: 10.13205/j.hjgc.202009004
Abstract:
Taking the river network in Binhu district as an example, 41 points distributed throughout the river network were monitored in 2018 during the wet season (August) and dry season (November), and 2019 during the normal season (March), and 14 physicochemical indexes such as chlorophyll a (chl-a) and pH were measured. The river network was divided into four main river systems. Principal component analysis and correlation analysis were used to judge the influence of different water quality factors on chl-a concentration change, and the main influencing factors in each water system were preliminarily identified. The water quality factors were included in the linear stepwise regression analysis to obtain the equation of chl-a for each river system and the whole river network. The mechanism of these main factors affecting chl-a content change in the river network was discussed. The results showed that the overall average value of the monitoring in the three phases of chl-a in the river network was 22.617 mg/m3, and the average value in the three phases of abundant season, dry season and smooth season was 17.256, 48.878, 1.717 mg/m3, respectively. Spatially, the overall pattern of chl-a was that the Liangxi River system was the highest in the north of the river network, followed by Ligang in the east and Caowangjing in the southeast, and the lowest in Ludianqiao in the west. The CODMn permanganate index, SS, Hg and PO43- were significantly correlated with Chl-a in the whole river network. Meiliang bay water diversion played a supplementary role for algae in the northern river network, and the input dissolved or deposited nutrients, such as TP and TN, were important sources of algae growth in summer and autumn. The main water source of Maligang and Ludianqiaobang River system in the west was provided by Wuli lake, and their water quality was directly affected. The inflow of two tributaries of Caowangjing system in the southeast promoted the improvement of water quality.
Taking the river network in Binhu district as an example, 41 points distributed throughout the river network were monitored in 2018 during the wet season (August) and dry season (November), and 2019 during the normal season (March), and 14 physicochemical indexes such as chlorophyll a (chl-a) and pH were measured. The river network was divided into four main river systems. Principal component analysis and correlation analysis were used to judge the influence of different water quality factors on chl-a concentration change, and the main influencing factors in each water system were preliminarily identified. The water quality factors were included in the linear stepwise regression analysis to obtain the equation of chl-a for each river system and the whole river network. The mechanism of these main factors affecting chl-a content change in the river network was discussed. The results showed that the overall average value of the monitoring in the three phases of chl-a in the river network was 22.617 mg/m3, and the average value in the three phases of abundant season, dry season and smooth season was 17.256, 48.878, 1.717 mg/m3, respectively. Spatially, the overall pattern of chl-a was that the Liangxi River system was the highest in the north of the river network, followed by Ligang in the east and Caowangjing in the southeast, and the lowest in Ludianqiao in the west. The CODMn permanganate index, SS, Hg and PO43- were significantly correlated with Chl-a in the whole river network. Meiliang bay water diversion played a supplementary role for algae in the northern river network, and the input dissolved or deposited nutrients, such as TP and TN, were important sources of algae growth in summer and autumn. The main water source of Maligang and Ludianqiaobang River system in the west was provided by Wuli lake, and their water quality was directly affected. The inflow of two tributaries of Caowangjing system in the southeast promoted the improvement of water quality.
2020, 38(9): 31-35,42.
doi: 10.13205/j.hjgc.202009005
Abstract:
Aiming at solving the problems of the traditional A2/O process in treating wastewater with low C/N ratio and its low efficiency in nitrogen and phosphorus removal, a new multi-point-influent improvement A2/O process was proposed, and started with sludge inoculation. In the case of no additional carbon source, the actual domestic wastewater was used, and analysis on the start-up process of the membrane was conducted. The results showed that when the A2/O process was improved by sub-water feed, the filling rate of the suspended filler in the aerobic tank was 30%, and the DO was 1.5~3.0 mg/L, the start-up was completed in 21 days. Then the removal rates of COD, NH4+-N, TN and TP were 90.08%, 91.31% and 61.67% and 81.37%, respectively. This improved A2/O process by sub-water feed can overcome the limitation of carbon source shortage in the process of nitrogen and phosphorus removal. This new process realized the fast start-up and showed a higher treatment effect on nitrogen and phosphorus, and the water quality reached the Grade A standard of the Pollutant Discharge Standard for Urban Wastewater Treatment Plants (GB 18918-2002).
Aiming at solving the problems of the traditional A2/O process in treating wastewater with low C/N ratio and its low efficiency in nitrogen and phosphorus removal, a new multi-point-influent improvement A2/O process was proposed, and started with sludge inoculation. In the case of no additional carbon source, the actual domestic wastewater was used, and analysis on the start-up process of the membrane was conducted. The results showed that when the A2/O process was improved by sub-water feed, the filling rate of the suspended filler in the aerobic tank was 30%, and the DO was 1.5~3.0 mg/L, the start-up was completed in 21 days. Then the removal rates of COD, NH4+-N, TN and TP were 90.08%, 91.31% and 61.67% and 81.37%, respectively. This improved A2/O process by sub-water feed can overcome the limitation of carbon source shortage in the process of nitrogen and phosphorus removal. This new process realized the fast start-up and showed a higher treatment effect on nitrogen and phosphorus, and the water quality reached the Grade A standard of the Pollutant Discharge Standard for Urban Wastewater Treatment Plants (GB 18918-2002).
2020, 38(9): 36-42.
doi: 10.13205/j.hjgc.202009006
Abstract:
Nano-alumina modified polyvinyl alcohol-calcium alginate gel spheres (SA-PVA-AlNPs) were prepared by sol-gel method for adsorption removal of tetracycline in aqueous solution. Effects of nano-alumina dosage, initial solution pH and ionic strength on adsorption properties of gel spheres were investigated. It was beneficial to improve the adsorption properties of gel beads; the optimum pH value of SA-PVA-ALNPs adsorbed tetracycline was 3; increase of NaCl concentration didn't significantly affect the adsorption capacity of tetracycline by gel beads. Pseudo-second order model kinetics could better fit the kinetics of SA-PVA-ALNPs adsorption on tetracycline. Langmuir model could better fit the isothermal adsorption data, and the maximum adsorption capacity was 75.90 mg/g. Adsorption of tetracycline by SA-PVA-ALNPs mainly depended on cation bridging, n-π electron donor-acceptor interaction and hydrogen bonding.
Nano-alumina modified polyvinyl alcohol-calcium alginate gel spheres (SA-PVA-AlNPs) were prepared by sol-gel method for adsorption removal of tetracycline in aqueous solution. Effects of nano-alumina dosage, initial solution pH and ionic strength on adsorption properties of gel spheres were investigated. It was beneficial to improve the adsorption properties of gel beads; the optimum pH value of SA-PVA-ALNPs adsorbed tetracycline was 3; increase of NaCl concentration didn't significantly affect the adsorption capacity of tetracycline by gel beads. Pseudo-second order model kinetics could better fit the kinetics of SA-PVA-ALNPs adsorption on tetracycline. Langmuir model could better fit the isothermal adsorption data, and the maximum adsorption capacity was 75.90 mg/g. Adsorption of tetracycline by SA-PVA-ALNPs mainly depended on cation bridging, n-π electron donor-acceptor interaction and hydrogen bonding.
2020, 38(9): 43-47,199.
doi: 10.13205/j.hjgc.202009007
Abstract:
In SBR (Ⅰ) reactor, the granular-flocculent sludge coupled single-stage autotrophic nitrogen removal system was rapidly started, and then the change of nitrogen removal performance of granular and flocculent sludge before and after start-up was studied. The sludge before start-up and after the start of the system was sampled to carry out batch experiments and the changes of denitrification and anaerobic ammonium oxidation denitrification performance were investigated by inhibiting the activity of anaerobic ammonium oxidizing bacteria (AAOB) by methanol. The total nitrogen removal rate (NRE) of flocculent sludge increased from 10.14% before start-up, to 89.70% after start-up, of which the proportion of anaerobic ammonia oxidation increased from 2.23% before start-up to 83.70%, and the proportion of denitrification decreased from 7.91% to 5%~6%. The NRE of granular sludge increased from 3.90% before start-up to 83.20% after start-up, the proportion of anaerobic ammonium oxidation increased from less than 1% to 80.20%, and the proportion of denitrification decreased from 7.72% to 2%~3%.
In SBR (Ⅰ) reactor, the granular-flocculent sludge coupled single-stage autotrophic nitrogen removal system was rapidly started, and then the change of nitrogen removal performance of granular and flocculent sludge before and after start-up was studied. The sludge before start-up and after the start of the system was sampled to carry out batch experiments and the changes of denitrification and anaerobic ammonium oxidation denitrification performance were investigated by inhibiting the activity of anaerobic ammonium oxidizing bacteria (AAOB) by methanol. The total nitrogen removal rate (NRE) of flocculent sludge increased from 10.14% before start-up, to 89.70% after start-up, of which the proportion of anaerobic ammonia oxidation increased from 2.23% before start-up to 83.70%, and the proportion of denitrification decreased from 7.91% to 5%~6%. The NRE of granular sludge increased from 3.90% before start-up to 83.20% after start-up, the proportion of anaerobic ammonium oxidation increased from less than 1% to 80.20%, and the proportion of denitrification decreased from 7.72% to 2%~3%.
2020, 38(9): 48-52,167.
doi: 10.13205/j.hjgc.202009008
Abstract:
Taking 11 moderately-eutrophic lakes and 7 lightly-eutrophic lakes in Jiangxi Province as the research objects, Pearson correlation analysis and principal component analysis were used to study the phosphorus occurrence forms, characteristics, forms and sources of sediments from the two types of lakes. The results showed that in the analysis of phosphorus forms, the average content of all forms of phosphorus in the two types of lakes was in the sequence of TP>IP>Fe/Al-P>Ca-P>OP, and the average content of the moderately-eutrophic lakes was lower than the lightly-eutrophic lakes. IP, Fe/Al-P, Ca-P, OP accounted for the average weight ratio of TP of the moderately-eutrophic lakes was 75.08%, 54.22%, 27.89%, 20.64% and for the lightly-eutrophic lakes was 72.85%, 56.02% 27.31%, 26.76%. The main source of phosphorus form was IP, supplemented by OP, while IP was mainly dominated by Fe/Al-P. Correlation analysis showed that TP-IP and TP-Fe/Al-P in both types of lakes were significantly correlated at α=0.05. In the moderately-eutrophic lakes, IP-Fe/Al-P was correlated at α=0.10, and IP-Fe/Al-P in the lightly-eutrophic lakes were significantly correlated at α=0.05; principal component analysis showed that the dominating type of influencing factors of the moderately-eutrophic lakes were Fe/Al-P and OP, and the secondary type of impact factors were IP and Ca-P, and the influencing factors of the lightly-eutrophic lakes were Fe/Al-P, OP and Ca-P; the difference in phosphorus morphological characteristics of sediments in two types of lakes mainly depended on Fe/Al-P. The difference in phosphorus occurrence characteristics of sediments in the moderately-eutrophic lakes was mainly determined by unsteady phosphorus or bioavailable phosphorus. The lightly-eutrophic lakes was determined by TP. This study could provide a reference for the study of phosphorus occurrence patterns in sediments of lakes with different eutrophication types.
Taking 11 moderately-eutrophic lakes and 7 lightly-eutrophic lakes in Jiangxi Province as the research objects, Pearson correlation analysis and principal component analysis were used to study the phosphorus occurrence forms, characteristics, forms and sources of sediments from the two types of lakes. The results showed that in the analysis of phosphorus forms, the average content of all forms of phosphorus in the two types of lakes was in the sequence of TP>IP>Fe/Al-P>Ca-P>OP, and the average content of the moderately-eutrophic lakes was lower than the lightly-eutrophic lakes. IP, Fe/Al-P, Ca-P, OP accounted for the average weight ratio of TP of the moderately-eutrophic lakes was 75.08%, 54.22%, 27.89%, 20.64% and for the lightly-eutrophic lakes was 72.85%, 56.02% 27.31%, 26.76%. The main source of phosphorus form was IP, supplemented by OP, while IP was mainly dominated by Fe/Al-P. Correlation analysis showed that TP-IP and TP-Fe/Al-P in both types of lakes were significantly correlated at α=0.05. In the moderately-eutrophic lakes, IP-Fe/Al-P was correlated at α=0.10, and IP-Fe/Al-P in the lightly-eutrophic lakes were significantly correlated at α=0.05; principal component analysis showed that the dominating type of influencing factors of the moderately-eutrophic lakes were Fe/Al-P and OP, and the secondary type of impact factors were IP and Ca-P, and the influencing factors of the lightly-eutrophic lakes were Fe/Al-P, OP and Ca-P; the difference in phosphorus morphological characteristics of sediments in two types of lakes mainly depended on Fe/Al-P. The difference in phosphorus occurrence characteristics of sediments in the moderately-eutrophic lakes was mainly determined by unsteady phosphorus or bioavailable phosphorus. The lightly-eutrophic lakes was determined by TP. This study could provide a reference for the study of phosphorus occurrence patterns in sediments of lakes with different eutrophication types.
2020, 38(9): 53-58,223.
doi: 10.13205/j.hjgc.202009009
Abstract:
The removal efficiency of reed wetland under different water depth conditions (5, 10, 15, 20, 25 cm) to nitrogen and phosphorus in Yitong River was studied. The results showed that shallow water was conducive to the nitrification and volatilization of NH4+-N. The removal efficiency of TN and NH4+-N was much higher when water depth was 5 cm, and that of NO3--N was much better when water depth was 10 cm. However, the removal efficiency of TN and NH4+-N was significantly reduced when water depth was 25 cm. The adsorption and transformation of NH4+-N played a dominant role in the attenuation of TN. The correlation between phosphorus removal rate and water depth was relatively lower, indicating that phosphorus removal was mainly through chemical transformation and adsorption. According to the influence of water depth on pollutant removal in wetlands, a floating wetland with automatic depth adjustment was designed. The concentrations of TN, NH4+-N and TP in the river in the study area were obviously reduced by the floating wetlands, thus the water quality was improved.
The removal efficiency of reed wetland under different water depth conditions (5, 10, 15, 20, 25 cm) to nitrogen and phosphorus in Yitong River was studied. The results showed that shallow water was conducive to the nitrification and volatilization of NH4+-N. The removal efficiency of TN and NH4+-N was much higher when water depth was 5 cm, and that of NO3--N was much better when water depth was 10 cm. However, the removal efficiency of TN and NH4+-N was significantly reduced when water depth was 25 cm. The adsorption and transformation of NH4+-N played a dominant role in the attenuation of TN. The correlation between phosphorus removal rate and water depth was relatively lower, indicating that phosphorus removal was mainly through chemical transformation and adsorption. According to the influence of water depth on pollutant removal in wetlands, a floating wetland with automatic depth adjustment was designed. The concentrations of TN, NH4+-N and TP in the river in the study area were obviously reduced by the floating wetlands, thus the water quality was improved.
2020, 38(9): 59-62,246.
doi: 10.13205/j.hjgc.202009010
Abstract:
Taking the river eutrophication control as the research object, the eutrophic treatment of the river course was carried out by introducing clear natural water into the river, underwater planting submerged macrophytes, polyculture of silver carp and bighead carp, and applying advanced in-situ restoration devices, in order to form an integrated ecological restoration system. The algal bloom index was measured at 5 sampling sites in Foshan from August 2017 to July 2018. The results showed that the concentration of total nitrogen (TN), total phosphorus (TP), potassium permanganate salt index (CODMn) and ammonia nitrogen (NH3-N) in the river water decreased significantly, and the transparency of the water increased significantly. It showed that the integrated ecological restoration system could be widely used for the treatment of urban river with lower risk and better treatment effect.
Taking the river eutrophication control as the research object, the eutrophic treatment of the river course was carried out by introducing clear natural water into the river, underwater planting submerged macrophytes, polyculture of silver carp and bighead carp, and applying advanced in-situ restoration devices, in order to form an integrated ecological restoration system. The algal bloom index was measured at 5 sampling sites in Foshan from August 2017 to July 2018. The results showed that the concentration of total nitrogen (TN), total phosphorus (TP), potassium permanganate salt index (CODMn) and ammonia nitrogen (NH3-N) in the river water decreased significantly, and the transparency of the water increased significantly. It showed that the integrated ecological restoration system could be widely used for the treatment of urban river with lower risk and better treatment effect.
2020, 38(9): 63-70.
doi: 10.13205/j.hjgc.202009011
Abstract:
Water quality safety is not only related to the healthy development of the ecological environment, but also closely related to the quality of human life. Toxicity testing of water bodies is an important mean to ensure the water quality. Firstly, the characteristics and application scope of the tested organisms, such as fish and algae, was introduced from the perspective of biological species in this paper. Secondly, the characterization indicators of toxicity at different biological levels were reviewed. The cell-based detection method could achieve fast and online toxicity testing. Finally, the future development direction of toxicity testing was prospected and a new research idea was provided.
Water quality safety is not only related to the healthy development of the ecological environment, but also closely related to the quality of human life. Toxicity testing of water bodies is an important mean to ensure the water quality. Firstly, the characteristics and application scope of the tested organisms, such as fish and algae, was introduced from the perspective of biological species in this paper. Secondly, the characterization indicators of toxicity at different biological levels were reviewed. The cell-based detection method could achieve fast and online toxicity testing. Finally, the future development direction of toxicity testing was prospected and a new research idea was provided.
2020, 38(9): 71-75,230.
doi: 10.13205/j.hjgc.202009012
Abstract:
In this paper, a nozzle-plate-cylinder reactor was developed and the effect of different factors on inactivation rate of the Escherichia coli(E. coli)in the water with the nanosecond negative pulsed air discharge at atmospheric pressure were investigated. The air flow was injected into the reactor through the discharge nozzle. The active species flow were produced in the discharge process and carried by the air flow to reach the the liquid. The results showed that the inactivation rate increased with the rise of discharge voltage, the pulse repetition rate and the discharge duration time. It increased firstly and then decreased with the air flow rate and decreased with the diameter of the electrode. The inactivation rate reached 91% when a 1.30 mm diameter electrode was adopted under the discharge duration time of 12 min, the disharge peak voltage of -32 kV, repeat frequenty of 80 Hz, and the air flow rate of 80 mL/min.
In this paper, a nozzle-plate-cylinder reactor was developed and the effect of different factors on inactivation rate of the Escherichia coli(E. coli)in the water with the nanosecond negative pulsed air discharge at atmospheric pressure were investigated. The air flow was injected into the reactor through the discharge nozzle. The active species flow were produced in the discharge process and carried by the air flow to reach the the liquid. The results showed that the inactivation rate increased with the rise of discharge voltage, the pulse repetition rate and the discharge duration time. It increased firstly and then decreased with the air flow rate and decreased with the diameter of the electrode. The inactivation rate reached 91% when a 1.30 mm diameter electrode was adopted under the discharge duration time of 12 min, the disharge peak voltage of -32 kV, repeat frequenty of 80 Hz, and the air flow rate of 80 mL/min.
2020, 38(9): 76-81.
doi: 10.13205/j.hjgc.202009013
Abstract:
As one of the low-impact development measures in sponge city, green roofs showed a certain effect of rainwater runoff retention and pollution interception during actual rainfall events, which effectively alleviated the current situation of urban waterlogging and non-point source pollution. The extensive green roof was suitable for the practical application of the project due to a series of advantages, such as lower roof load requirements, easier subsequent maintenance and less cost. Therefore, research on the influencing factors of rainwater runoff retention and pollution interception effect of extensive green roof had certain practical guiding significance for future engineering application. Based on a review of the domestic and foreign researches on the influencing factors of rainwater runoff retention and pollution interception in recent years, the deficiencies of the related research and the prospects for future research and practice were pointed out.
As one of the low-impact development measures in sponge city, green roofs showed a certain effect of rainwater runoff retention and pollution interception during actual rainfall events, which effectively alleviated the current situation of urban waterlogging and non-point source pollution. The extensive green roof was suitable for the practical application of the project due to a series of advantages, such as lower roof load requirements, easier subsequent maintenance and less cost. Therefore, research on the influencing factors of rainwater runoff retention and pollution interception effect of extensive green roof had certain practical guiding significance for future engineering application. Based on a review of the domestic and foreign researches on the influencing factors of rainwater runoff retention and pollution interception in recent years, the deficiencies of the related research and the prospects for future research and practice were pointed out.
2020, 38(9): 82-88.
doi: 10.13205/j.hjgc.202009014
Abstract:
Urban shallow landscape lakes suffered high eutrophication risk because of their special characters and functions in the water circulation system. Using a landscape lake located in Chengdu in Southern China, with a mixture of point source pollution and non-point source pollution, to which sustainable ecological maintenance was more difficult, we explored the methodology of AQUATOX to simulate and predict the state of this lake. According to the one-year monitoring data of water quality parameters, and trophic index was used to assess the eutrophication state to characterizing water pollution status. Using the measured data to fit the model results, we analyzed the sensitive parameters of the model operation, and determined the relevant parameters to increase the accuracy of the model in predicting the water ecological evolution of the water body. Using the height-fitting model to determine the effect of TP, TN and NH3-N on the water quality of shallow water landscapes, and SWMM model to simulate the effect of LID measures on the reduction of rainwater pollution load in the lake. After LID measures, the stormwater runoff pollution load of total phosphorus and total nitrogen decreased by 59.34% and 58.39%, respectively, and the ammonia nitrogen load decreased by 21.94%. and the average reduction rates of TP, TN and NH3-N in water were 38.57%,42.2% and 58.31%, respectively, which provided theoretical guidance for eutrophication and ecological restoration of landscape waters.
Urban shallow landscape lakes suffered high eutrophication risk because of their special characters and functions in the water circulation system. Using a landscape lake located in Chengdu in Southern China, with a mixture of point source pollution and non-point source pollution, to which sustainable ecological maintenance was more difficult, we explored the methodology of AQUATOX to simulate and predict the state of this lake. According to the one-year monitoring data of water quality parameters, and trophic index was used to assess the eutrophication state to characterizing water pollution status. Using the measured data to fit the model results, we analyzed the sensitive parameters of the model operation, and determined the relevant parameters to increase the accuracy of the model in predicting the water ecological evolution of the water body. Using the height-fitting model to determine the effect of TP, TN and NH3-N on the water quality of shallow water landscapes, and SWMM model to simulate the effect of LID measures on the reduction of rainwater pollution load in the lake. After LID measures, the stormwater runoff pollution load of total phosphorus and total nitrogen decreased by 59.34% and 58.39%, respectively, and the ammonia nitrogen load decreased by 21.94%. and the average reduction rates of TP, TN and NH3-N in water were 38.57%,42.2% and 58.31%, respectively, which provided theoretical guidance for eutrophication and ecological restoration of landscape waters.
2020, 38(9): 89-94.
doi: 10.13205/j.hjgc.202009015
Abstract:
This study investigated the recovery of ammonium and phosphate from corn processing wastewater using magnetic MgO-biochar yielded from wood waste. Kinetics property was studied and the process reached equilibrium within 120 h. The maximum adsorption capacities of ammonium-nitrogen and phosphorus by the magnetic MgO-biochar reached 50.4 mg/g and 338.9 mg/g, respectively. According to the characterization, magnesium and iron oxides formed on the biochar surface. Chemisorption was the dominating mechanism for the recovery of ammonium, while chemisorption and chemical precipitation both responded for the recovery of phosphate using the magnetic MgO-biochar. The magnetic MgO-biochar enriched with ammonium and phosphate was a slow release fertilizer of ammonium and phosphate, while no obvious release of ferric ions was observed.
This study investigated the recovery of ammonium and phosphate from corn processing wastewater using magnetic MgO-biochar yielded from wood waste. Kinetics property was studied and the process reached equilibrium within 120 h. The maximum adsorption capacities of ammonium-nitrogen and phosphorus by the magnetic MgO-biochar reached 50.4 mg/g and 338.9 mg/g, respectively. According to the characterization, magnesium and iron oxides formed on the biochar surface. Chemisorption was the dominating mechanism for the recovery of ammonium, while chemisorption and chemical precipitation both responded for the recovery of phosphate using the magnetic MgO-biochar. The magnetic MgO-biochar enriched with ammonium and phosphate was a slow release fertilizer of ammonium and phosphate, while no obvious release of ferric ions was observed.
2020, 38(9): 95-100,112.
doi: 10.13205/j.hjgc.202009016
Abstract:
The adsorbent was prepared by combining the drinking water treatment sludge with the powdered activated carbon, in order to remove ammonia nitrogen from the water. The optimum composite mass ratio and calcination temperature of drinking water treatment sludge and powdered activated carbon were studied. The adsorbents were characterized by EDX, SEM, XRD, FTIR and BET. The influences of different parameters such as contact time of composite adsorbent, initial pH of ammonia nitrogen, dosage of adsorbent and initial concentration of ammonia nitrogen were investigated. The results indicated that the adsorption performance of the composite adsorbent was better than that of the raw sludge adsorbent. When the contact time was 5h and the pH was 9, the ammonia nitrogen removal effect was the best. The adsorption isotherms and adsorption kinetic model were fitted by the experimental results. It was found that the adsorption process of the composite adsorbent on ammonia nitrogen accorded with the Langmuir isotherm adsorption model and the second-order kinetic model.
The adsorbent was prepared by combining the drinking water treatment sludge with the powdered activated carbon, in order to remove ammonia nitrogen from the water. The optimum composite mass ratio and calcination temperature of drinking water treatment sludge and powdered activated carbon were studied. The adsorbents were characterized by EDX, SEM, XRD, FTIR and BET. The influences of different parameters such as contact time of composite adsorbent, initial pH of ammonia nitrogen, dosage of adsorbent and initial concentration of ammonia nitrogen were investigated. The results indicated that the adsorption performance of the composite adsorbent was better than that of the raw sludge adsorbent. When the contact time was 5h and the pH was 9, the ammonia nitrogen removal effect was the best. The adsorption isotherms and adsorption kinetic model were fitted by the experimental results. It was found that the adsorption process of the composite adsorbent on ammonia nitrogen accorded with the Langmuir isotherm adsorption model and the second-order kinetic model.
2020, 38(9): 101-105,144.
doi: 10.13205/j.hjgc.202009017
Abstract:
A total of 222 surface water samples from the upstream water system of Guanting Reservoir and Miyun Reservoir were collected at the same point in both plain and the abundant water periods. The contents of total nitrogen, ammonia nitrogen, nitrate and total phosphorus in raw water and the suspended solids were measured respectively. The distribution and pollution characteristics of nitrogen and phosphorus were discussed and evaluated with reference to the environmental quality standard of surface water (GB 3838-2002). The results showed that:1) the surface water in the study area was in eutrophication state, the nitrogen and phosphorus content in Yongding River system was relatively higher, and the high value points were mainly distributed in the cross section of the main stream of the Yanghe River; 2) the appearance of the high value point of nitrogen and phosphorus in the main stream of the main river was closely related to the discharge of urban wastewater in the upper reaches of the river, and the treatment of urban wastewater should be strengthened; 3) the samples of 78.26% total nitrogen (in abundont water period) and 91.59% (in plain water period) were inferior to class Ⅲ. Except for the upper reaches of the Yanghe River, the upper reaches of the Sanggan River and the Tang River systems, the total nitrogen in most of the sample sites of the other water systems was inferior to classⅤ. However, most of the samples of nitrate and ammonia nitrogen were defined to meet the standard limit, so it was suggested that the control of nitrate should be strengthened when setting the standard; 4) the samples of total phosphorus 33.04% (in abundant water period) and 14.02% (in plain water period) didn't meet the requirements of category Ⅲ, and mainly distributed in the middle section of the Yanghe River, Huliu River and the middle section of the tidal river waters. According to the present situation of surface water environmental quality, some suggestions for future work were put forward.
A total of 222 surface water samples from the upstream water system of Guanting Reservoir and Miyun Reservoir were collected at the same point in both plain and the abundant water periods. The contents of total nitrogen, ammonia nitrogen, nitrate and total phosphorus in raw water and the suspended solids were measured respectively. The distribution and pollution characteristics of nitrogen and phosphorus were discussed and evaluated with reference to the environmental quality standard of surface water (GB 3838-2002). The results showed that:1) the surface water in the study area was in eutrophication state, the nitrogen and phosphorus content in Yongding River system was relatively higher, and the high value points were mainly distributed in the cross section of the main stream of the Yanghe River; 2) the appearance of the high value point of nitrogen and phosphorus in the main stream of the main river was closely related to the discharge of urban wastewater in the upper reaches of the river, and the treatment of urban wastewater should be strengthened; 3) the samples of 78.26% total nitrogen (in abundont water period) and 91.59% (in plain water period) were inferior to class Ⅲ. Except for the upper reaches of the Yanghe River, the upper reaches of the Sanggan River and the Tang River systems, the total nitrogen in most of the sample sites of the other water systems was inferior to classⅤ. However, most of the samples of nitrate and ammonia nitrogen were defined to meet the standard limit, so it was suggested that the control of nitrate should be strengthened when setting the standard; 4) the samples of total phosphorus 33.04% (in abundant water period) and 14.02% (in plain water period) didn't meet the requirements of category Ⅲ, and mainly distributed in the middle section of the Yanghe River, Huliu River and the middle section of the tidal river waters. According to the present situation of surface water environmental quality, some suggestions for future work were put forward.
2020, 38(9): 106-112.
doi: 10.13205/j.hjgc.202009018
Abstract:
This study compared the performance of open-ended MABR and closed-ended MABR for high ammonium (NH4+-N) synthetic wastewater treatment. The results demonstrated that the two MABRs rapidly formed biofilm in 8 days,but in the open-ended MABR, biofilm content and nitrogen removal efficiencies were higher than those of the closed-ended one. The average removal efficiencies of NH4+-N, TN and COD in open-ended MABR for high ammonium synthetic wastewater treatment were all nearly 20% higher than those in closed-ended one, indicating a better nitrogen and COD removal performance. The high-throughput sequencing analysis revealed that rapid enrichment of HN-AD bacteria was achieved during the biofilm formation, and high abundances of HN-AD bacteria (22.1% of Acinetobacter, 43.2% of Pseudomonas) were kept during the stabilization of the open-ended MABR; but closed-ended MABR didn't achieve HN-AD bacteria enrichment. A higher DO condition provided by open-ended MABR promoted greater abundance of HN-AD bacteria than the close-ended one, to enhanced the treatment of high ammonium wastewater.
This study compared the performance of open-ended MABR and closed-ended MABR for high ammonium (NH4+-N) synthetic wastewater treatment. The results demonstrated that the two MABRs rapidly formed biofilm in 8 days,but in the open-ended MABR, biofilm content and nitrogen removal efficiencies were higher than those of the closed-ended one. The average removal efficiencies of NH4+-N, TN and COD in open-ended MABR for high ammonium synthetic wastewater treatment were all nearly 20% higher than those in closed-ended one, indicating a better nitrogen and COD removal performance. The high-throughput sequencing analysis revealed that rapid enrichment of HN-AD bacteria was achieved during the biofilm formation, and high abundances of HN-AD bacteria (22.1% of Acinetobacter, 43.2% of Pseudomonas) were kept during the stabilization of the open-ended MABR; but closed-ended MABR didn't achieve HN-AD bacteria enrichment. A higher DO condition provided by open-ended MABR promoted greater abundance of HN-AD bacteria than the close-ended one, to enhanced the treatment of high ammonium wastewater.
2020, 38(9): 113-118.
doi: 10.13205/j.hjgc.202009019
Abstract:
Using an anaerobic-aerobic sequencing batch reactor (AO-SBR), the glycogen accumulating organisms (GAOs) had been enriched with sodium acetate as the carbon source and the P/C ratio lower than 2/100. Cultured in anaerobic-anoxic operation mode, the acclimated GAOs could perform endogenous denitrification reaction with NOx--N as electron acceptor and poly-β-hydroxyalkanoate(PHA) as electron donor, where PHB (poly-β-hydro-xybutyrate) accounted for more than 80% of the PHA decomposition and utilization. The higher NO2- concentration inhibited the activity of DGAOs, which led to the decrease of PHA synthesis. More energy from PHA decomposition would be used for glycogen storage. During the reduction process of NO3- and NO2-, the PHA degradation rate was 19.28 mg/(g·h) and 10.02 mg/(g·h) respectively, which resulted in the related endogenous denitrification rates were 3.32 mg/(g·h) and 2.29 mg/(g·h). The TN removal efficiency reached more than 95% in the end. With the increase of NO2-/NOx-, the N2O yield during the endogenous denitrification process increased from 29.1% to 59.0%. The higher NO2- inhibition on the activity of Nos, as well as the electron competition between Nir and Nos, resulted in the higher N2O production during PHA-driven denitrification by DGAOs.
Using an anaerobic-aerobic sequencing batch reactor (AO-SBR), the glycogen accumulating organisms (GAOs) had been enriched with sodium acetate as the carbon source and the P/C ratio lower than 2/100. Cultured in anaerobic-anoxic operation mode, the acclimated GAOs could perform endogenous denitrification reaction with NOx--N as electron acceptor and poly-β-hydroxyalkanoate(PHA) as electron donor, where PHB (poly-β-hydro-xybutyrate) accounted for more than 80% of the PHA decomposition and utilization. The higher NO2- concentration inhibited the activity of DGAOs, which led to the decrease of PHA synthesis. More energy from PHA decomposition would be used for glycogen storage. During the reduction process of NO3- and NO2-, the PHA degradation rate was 19.28 mg/(g·h) and 10.02 mg/(g·h) respectively, which resulted in the related endogenous denitrification rates were 3.32 mg/(g·h) and 2.29 mg/(g·h). The TN removal efficiency reached more than 95% in the end. With the increase of NO2-/NOx-, the N2O yield during the endogenous denitrification process increased from 29.1% to 59.0%. The higher NO2- inhibition on the activity of Nos, as well as the electron competition between Nir and Nos, resulted in the higher N2O production during PHA-driven denitrification by DGAOs.
2020, 38(9): 119-125.
doi: 10.13205/j.hjgc.202009020
Abstract:
Moving bed biofilm reactor (MBBR) was used to treat simulated wastewater. The effect of ammonia-nitrogen concentration (20, 30, 50, 100, 200 mg/L) on the treatment efficiency of MBBR was investigated. By using 16S rDNA high-throughput sequencing technique, the changes in the microbial community structure of MBBR under different ammonia-nitrogen concentration were analyzed. The results indicated that the lower ammonia-nitrogen concentration, the more beneficial for the removal of ammonia nitrogen, but the less impact on the removal of COD, when ammonia-nitrogen concentration was 30~100 mg/L. When ammonia-nitrogen concentration was 20, 50 and 200 mg/L, Ottowia was the top dominant bacterial genus, whose relative abundances were 66.76%, 34.40%, 53.88%, respectively. When ammonia-nitrogen concentration was 30, 100 mg/L, Ottowia was replaced by Arcobacter, Hydrogenophag, etc. The fluctuation of microbial community structure may be related to the competition for dominant position between various denitrifying bacteria and Ottowia. The relative abundance of autotrophic nitrification bacteria was stable at about 0.3%, which was not affected by ammonia nitrogen concentration. The inhibiting effect of high concentration ammonia nitrogen on nitrifying bacteria might be due to the inhibition of their microbial activity. The influent ammonia-nitrogen concentration affected the microbial community structure in MBBR biofilm.
Moving bed biofilm reactor (MBBR) was used to treat simulated wastewater. The effect of ammonia-nitrogen concentration (20, 30, 50, 100, 200 mg/L) on the treatment efficiency of MBBR was investigated. By using 16S rDNA high-throughput sequencing technique, the changes in the microbial community structure of MBBR under different ammonia-nitrogen concentration were analyzed. The results indicated that the lower ammonia-nitrogen concentration, the more beneficial for the removal of ammonia nitrogen, but the less impact on the removal of COD, when ammonia-nitrogen concentration was 30~100 mg/L. When ammonia-nitrogen concentration was 20, 50 and 200 mg/L, Ottowia was the top dominant bacterial genus, whose relative abundances were 66.76%, 34.40%, 53.88%, respectively. When ammonia-nitrogen concentration was 30, 100 mg/L, Ottowia was replaced by Arcobacter, Hydrogenophag, etc. The fluctuation of microbial community structure may be related to the competition for dominant position between various denitrifying bacteria and Ottowia. The relative abundance of autotrophic nitrification bacteria was stable at about 0.3%, which was not affected by ammonia nitrogen concentration. The inhibiting effect of high concentration ammonia nitrogen on nitrifying bacteria might be due to the inhibition of their microbial activity. The influent ammonia-nitrogen concentration affected the microbial community structure in MBBR biofilm.
2020, 38(9): 126-132.
doi: 10.13205/j.hjgc.202009021
Abstract:
In the evaluation of eutrophication of water body in Jiuli Lake subsidence wetland park in Jiangsu Province, 10 water quality monitoring spots were under observation with TP, TN, CODMn, Chl.a, SD as the evaluation indicators during spring, summer, autumn and winter of 2018. And combining secondary fuzzy comprehensive evaluation model which based on the idea of "pressure-response" and entropy weight, the evaluation results proved the rationality and objectivity of the model applied to the evaluation of eutrophication of Jiulihu wetland in Jiangsu Province. The eutrophication status of Jiulihu wetland in Jiangsu Province was highly correlated with seasonal changes. Each monitoring spot was in the eutrophication level of the mesotrophic level and eutrophic level.
In the evaluation of eutrophication of water body in Jiuli Lake subsidence wetland park in Jiangsu Province, 10 water quality monitoring spots were under observation with TP, TN, CODMn, Chl.a, SD as the evaluation indicators during spring, summer, autumn and winter of 2018. And combining secondary fuzzy comprehensive evaluation model which based on the idea of "pressure-response" and entropy weight, the evaluation results proved the rationality and objectivity of the model applied to the evaluation of eutrophication of Jiulihu wetland in Jiangsu Province. The eutrophication status of Jiulihu wetland in Jiangsu Province was highly correlated with seasonal changes. Each monitoring spot was in the eutrophication level of the mesotrophic level and eutrophic level.
2020, 38(9): 133-138,207.
doi: 10.13205/j.hjgc.202009022
Abstract:
Effect of biochar powders prepared from different biomass materials on the composition (content of protein (PN) and polysaccharide (PS)) of soluble microbial products (SMP) and extracellular polymers (EPS) in activated sludge were studied using SBR process. MLVSS/MLSS changes of activated sludge and the nitrogen and phosphorus content of wastewater were analyzed. The results showed that the content of protein in activated sludge SMP decreased by 62.26%~76.58% after adding biochar, and the content of protein in activated sludge EPS increased by 17.83%~32.84%. However, the effect of biochar on the content of PS in activated sludge was not obvious. Activated sludge added with biochar contained more amino acids or tryptophan, tyrosine and phenylalanine in the protein. Pig manure biochar (PMB) showed the most obviously effect on activated sludge, and there were more aromatics and nucleic acids in the freeze-dried EPS. The added biochar acted as the connecting bridge which increased the size of sludge flocs, changed the growth and metabolism environment of the microorganisms. Then, the amount of microorganisms in the sludge increased significantly, and the conversion efficiency of nitrogen was improved obviously. Ammonia nitrogen was converted to nitrite nitrogen rapidly and reached a relative high concentration. At the same time, the activated sludge showed better phosphorus removal effect after adding biochar.
Effect of biochar powders prepared from different biomass materials on the composition (content of protein (PN) and polysaccharide (PS)) of soluble microbial products (SMP) and extracellular polymers (EPS) in activated sludge were studied using SBR process. MLVSS/MLSS changes of activated sludge and the nitrogen and phosphorus content of wastewater were analyzed. The results showed that the content of protein in activated sludge SMP decreased by 62.26%~76.58% after adding biochar, and the content of protein in activated sludge EPS increased by 17.83%~32.84%. However, the effect of biochar on the content of PS in activated sludge was not obvious. Activated sludge added with biochar contained more amino acids or tryptophan, tyrosine and phenylalanine in the protein. Pig manure biochar (PMB) showed the most obviously effect on activated sludge, and there were more aromatics and nucleic acids in the freeze-dried EPS. The added biochar acted as the connecting bridge which increased the size of sludge flocs, changed the growth and metabolism environment of the microorganisms. Then, the amount of microorganisms in the sludge increased significantly, and the conversion efficiency of nitrogen was improved obviously. Ammonia nitrogen was converted to nitrite nitrogen rapidly and reached a relative high concentration. At the same time, the activated sludge showed better phosphorus removal effect after adding biochar.
2020, 38(9): 139-144.
doi: 10.13205/j.hjgc.202009023
Abstract:
By analyzing the impact of pollutant migration in the runoff of the vegetation buffer zone on the bank of the Dongxinkai River, the removal effect of nitrogen and phosphorus on the typical pollutants in the buffer zone on both banks was studied, and the plant configuration structure of the buffer zone was optimized. The results showed that the optimally configured vegetation buffer zone had obvious advantages over the original vegetation buffer zone in the interception effect of nitrogen and phosphorus pollutants. For the two indicators of ammonia nitrogen and total nitrogen, it had a significant reduction effect. Alfalfa plots had a reduction rate of more than 30%, 30%, and 25% for ammonia nitrogen, total nitrogen, and total phosphorus respectively, higher than other vegetation configuration plots, and had a solid root system, and relatively stronger adaptability and lower planting cost; plants had different retention effects on nitrogen and phosphorus in the buffer zone in different growth periods. The reduction rate of vegetation buffer zone in mature stage to TN and TP was 30% and 25% respectively, which was higher than that in the tillering stage. The reduction rate of nitrogen and phosphorus the was increased by more than 80%.
By analyzing the impact of pollutant migration in the runoff of the vegetation buffer zone on the bank of the Dongxinkai River, the removal effect of nitrogen and phosphorus on the typical pollutants in the buffer zone on both banks was studied, and the plant configuration structure of the buffer zone was optimized. The results showed that the optimally configured vegetation buffer zone had obvious advantages over the original vegetation buffer zone in the interception effect of nitrogen and phosphorus pollutants. For the two indicators of ammonia nitrogen and total nitrogen, it had a significant reduction effect. Alfalfa plots had a reduction rate of more than 30%, 30%, and 25% for ammonia nitrogen, total nitrogen, and total phosphorus respectively, higher than other vegetation configuration plots, and had a solid root system, and relatively stronger adaptability and lower planting cost; plants had different retention effects on nitrogen and phosphorus in the buffer zone in different growth periods. The reduction rate of vegetation buffer zone in mature stage to TN and TP was 30% and 25% respectively, which was higher than that in the tillering stage. The reduction rate of nitrogen and phosphorus the was increased by more than 80%.
2020, 38(9): 154-158,125.
doi: 10.13205/j.hjgc.202009025
Abstract:
Condensable particulate matter (CPM) contributes considerably to the fine particles (PM2.5) emitted from coking plant in iron and steel plants. However, the emission characteristics of CPM from coking plants are still unclear. In this study, indirect dilution method was applied to collect the CPM emitted from coking plant. The concentrations and chemical compositions of CPM at the flue gas desulfurization inlet and the stack were analyzed systematically. The concentrations of CPM at the flue gas desulfurization inlet and the stack were 9.5 mg/m3 and 1.2 mg/m3, respectively, which were 14 times and 4 times of fine filterable particulate matter (FPM2.5), respectively. The most dominant constituents in CPM at the flue gas desulfurization inlet and the stack were water-soluble ions of Cl- and K+, and then organic components. The organic constituents in CPM were mainly alkenes, cyclanes, alkanes at the flue gas desulfurization inlet and alcohols, alkenes, phenols at the stack. The comined process, dry desulfurization with sodium bicarbonate-fabric filter-selective catalytic reduction under medium and low temperature could remove a certain amount of condensable gaseous pollutants synergistically, with a removal rate for CPM of 87.3%.
Condensable particulate matter (CPM) contributes considerably to the fine particles (PM2.5) emitted from coking plant in iron and steel plants. However, the emission characteristics of CPM from coking plants are still unclear. In this study, indirect dilution method was applied to collect the CPM emitted from coking plant. The concentrations and chemical compositions of CPM at the flue gas desulfurization inlet and the stack were analyzed systematically. The concentrations of CPM at the flue gas desulfurization inlet and the stack were 9.5 mg/m3 and 1.2 mg/m3, respectively, which were 14 times and 4 times of fine filterable particulate matter (FPM2.5), respectively. The most dominant constituents in CPM at the flue gas desulfurization inlet and the stack were water-soluble ions of Cl- and K+, and then organic components. The organic constituents in CPM were mainly alkenes, cyclanes, alkanes at the flue gas desulfurization inlet and alcohols, alkenes, phenols at the stack. The comined process, dry desulfurization with sodium bicarbonate-fabric filter-selective catalytic reduction under medium and low temperature could remove a certain amount of condensable gaseous pollutants synergistically, with a removal rate for CPM of 87.3%.
2020, 38(9): 159-167.
doi: 10.13205/j.hjgc.202009026
Abstract:
Emission control of heavy-duty (HD) diesel engines is one of the focuses to reduce the air pollution. California Air Resources Board (CARB) had taken the action on issuing a white paper to further limit the emission of heavy-duty vehicles, which especially suggested reducing the NOx emission to maximum 90% based on EPA2010 legislation (0.027 g/(kW·h)). To satisfy the ultra-low emission requirements, global related research institutes carried on a lot of tasks to explore the potential pathway for the future heavy duty after-treatment solutions. To some extent, these actions purged the upgradation of emission legislation around the world, including Europe and China. This paper reviewed the current status of HD diesel engine emission control and available approaches for future emission control obtained from published materials and author's study from the point of aftertreatment component. Thermal management and emission control system should be considered together during the engine design. The paper compared different solutions such as passive NOx absorber(PNA)/close-coupled SCR(cc-SCR)/SCR on Filter(SCRF) in NOx control, ash management and PN emission in DPF control, electrical heated catalyst (EHC)/diesel burner in aftertreatment temperature control.
Emission control of heavy-duty (HD) diesel engines is one of the focuses to reduce the air pollution. California Air Resources Board (CARB) had taken the action on issuing a white paper to further limit the emission of heavy-duty vehicles, which especially suggested reducing the NOx emission to maximum 90% based on EPA2010 legislation (0.027 g/(kW·h)). To satisfy the ultra-low emission requirements, global related research institutes carried on a lot of tasks to explore the potential pathway for the future heavy duty after-treatment solutions. To some extent, these actions purged the upgradation of emission legislation around the world, including Europe and China. This paper reviewed the current status of HD diesel engine emission control and available approaches for future emission control obtained from published materials and author's study from the point of aftertreatment component. Thermal management and emission control system should be considered together during the engine design. The paper compared different solutions such as passive NOx absorber(PNA)/close-coupled SCR(cc-SCR)/SCR on Filter(SCRF) in NOx control, ash management and PN emission in DPF control, electrical heated catalyst (EHC)/diesel burner in aftertreatment temperature control.
2020, 38(9): 168-174.
doi: 10.13205/j.hjgc.202009027
Abstract:
With the increasing environmental problems, the removal of nitrogen oxides (NOx) in flue gas has become an urgent problem. In this paper, the cordierite honeycomb-supported denitration catalyst was prepared by simultaneous impregnation method. The effects of vanadium content, temperature, gas hourly space velocity and acid treatment on the denitration efficiency of cordierite-supported denitration catalyst were studied. At the same time, the catalyst was subjected to physical and chemical characterization by means including BET and XRD. The results showed that the supported denitration catalyst could achieve good denitration effect, the denitration efficiency gradually increased with the increase of V2O5 content, as the temperature rose, the efficiency increased first and then decreased; at 340℃, the supported catalyst achieved the best denitration effect, the denitration efficiency was above 98% (the gas hourly space velocity was 18000 h-1); the de-NOx efficiency of sulfuric acid treated catalyst increased by 1~3 percents, while that of hydrochloric acid treated catalyst decreased by 4~8 percents; the loading rate of the supported catalyst was maintained at about 25%, and the shedding rate after ultrasonic treatment was less than 10%.
With the increasing environmental problems, the removal of nitrogen oxides (NOx) in flue gas has become an urgent problem. In this paper, the cordierite honeycomb-supported denitration catalyst was prepared by simultaneous impregnation method. The effects of vanadium content, temperature, gas hourly space velocity and acid treatment on the denitration efficiency of cordierite-supported denitration catalyst were studied. At the same time, the catalyst was subjected to physical and chemical characterization by means including BET and XRD. The results showed that the supported denitration catalyst could achieve good denitration effect, the denitration efficiency gradually increased with the increase of V2O5 content, as the temperature rose, the efficiency increased first and then decreased; at 340℃, the supported catalyst achieved the best denitration effect, the denitration efficiency was above 98% (the gas hourly space velocity was 18000 h-1); the de-NOx efficiency of sulfuric acid treated catalyst increased by 1~3 percents, while that of hydrochloric acid treated catalyst decreased by 4~8 percents; the loading rate of the supported catalyst was maintained at about 25%, and the shedding rate after ultrasonic treatment was less than 10%.
2020, 38(9): 175-184.
doi: 10.13205/j.hjgc.202009028
Abstract:
Medical waste incinerator fly ash (MWIFA) has been classified as hazardous waste in China due to its special characteristics of high concentrations of chlorine salt, carbon constituents, heavy metals, and dioxins (PCDD/Fs), which may cause serious harm to environment and human health if managed and disposed improperly. There were few comprehensive studies on treatment and disposal of MWIFA. The pollution characteristics of heavy metals and dioxins in MWIFA were presented in this study. Then, the status of various treatment technologies of fly ash, such as chemical stabilization method, cement solidification, thermal treatment, hydrothermal treatment and flotation technology were reviewed. Finally, the development and disadvantage of thermal treatment, hydrothermal treatment and flotation technology in treating heavy metals and dioxins of MWIFA were described in detail, and the prospect was also predicted in the future.
Medical waste incinerator fly ash (MWIFA) has been classified as hazardous waste in China due to its special characteristics of high concentrations of chlorine salt, carbon constituents, heavy metals, and dioxins (PCDD/Fs), which may cause serious harm to environment and human health if managed and disposed improperly. There were few comprehensive studies on treatment and disposal of MWIFA. The pollution characteristics of heavy metals and dioxins in MWIFA were presented in this study. Then, the status of various treatment technologies of fly ash, such as chemical stabilization method, cement solidification, thermal treatment, hydrothermal treatment and flotation technology were reviewed. Finally, the development and disadvantage of thermal treatment, hydrothermal treatment and flotation technology in treating heavy metals and dioxins of MWIFA were described in detail, and the prospect was also predicted in the future.
2020, 38(9): 185-189.
doi: 10.13205/j.hjgc.202009029
Abstract:
In this study, the combustion characteristics of combustible waste, pulverized coal and their mixture were analyzed by thermogravimetric analysis. The results showed that the thermogravimetric curves of combustible waste had two obvious weight loss regions in the temperature range of 220~500℃, and only one obvious weight loss region of pulverized coal in the temperature range of 300~600℃. Combustible waste had good ignition performance, and the ignition point was 220℃. The ignition point of combustible waste mixed with pulverized coal was slightly higher than that of the combustible waste, but it was also obviously lower than that of pulverized coal combustion alone. Mixed combustion basically maintained the ignition characteristics of the combustible waste, when mixed with pulverized coal. When the blending proportion of combustible waste was not more than 80%, there was an obvious synergistic promoting effect between combustible waste and pulverized coal mixed combustion. The comprehensive combustion characteristic index of combustible waste was 3.91×10-7/(min2·K3), obviously higher than that of the pulverized coal. The addition of the combustible waste could improve the comprehensive combustion performance of the pulverized coal, and the best ratio of combustible waste to pulverized coal was 4:1. The results of combustion kinetic analysis showed that the activity of the mixed fuel was higher than that of the combustible waste at 220~330℃ combustion stage, and the activity of the mixed fuel was slightly lower than that of the combustible waste at 320~570℃ combustion stage, but much higher than that of the pulverized coal. The addition amount of the combustible waste had little influence on activity of the mixed fuel in the two combustion stages.
In this study, the combustion characteristics of combustible waste, pulverized coal and their mixture were analyzed by thermogravimetric analysis. The results showed that the thermogravimetric curves of combustible waste had two obvious weight loss regions in the temperature range of 220~500℃, and only one obvious weight loss region of pulverized coal in the temperature range of 300~600℃. Combustible waste had good ignition performance, and the ignition point was 220℃. The ignition point of combustible waste mixed with pulverized coal was slightly higher than that of the combustible waste, but it was also obviously lower than that of pulverized coal combustion alone. Mixed combustion basically maintained the ignition characteristics of the combustible waste, when mixed with pulverized coal. When the blending proportion of combustible waste was not more than 80%, there was an obvious synergistic promoting effect between combustible waste and pulverized coal mixed combustion. The comprehensive combustion characteristic index of combustible waste was 3.91×10-7/(min2·K3), obviously higher than that of the pulverized coal. The addition of the combustible waste could improve the comprehensive combustion performance of the pulverized coal, and the best ratio of combustible waste to pulverized coal was 4:1. The results of combustion kinetic analysis showed that the activity of the mixed fuel was higher than that of the combustible waste at 220~330℃ combustion stage, and the activity of the mixed fuel was slightly lower than that of the combustible waste at 320~570℃ combustion stage, but much higher than that of the pulverized coal. The addition amount of the combustible waste had little influence on activity of the mixed fuel in the two combustion stages.
2020, 38(9): 190-193,88.
doi: 10.13205/j.hjgc.202009030
Abstract:
In China, the annual output of high temperature molten slag is higher than 6×108 t, which has a great value of heat. However, by now, most of heat resource can not be recovered. In this paper, four heat recovery technologies, including dry granulation, chemical method, waste heat utilization of cooling water and production using molten slag as the raw material, were discussed. The key factor for the application of heat recovery technology was the maximum utilization and economic efficiency. To recover heat resource, dry granulation and chemical method were adopted to treat the molten slag with lower content of active materials. Whereas, molten slag containing higher content of active materials needed to be treated without decreasing slag activity. Furthermore, waste heat utilization of cooling water could be adopted according to the actual condition. The difficulties in production using molten slag as the raw material should be overcome, which is beneficial for increasing the quality and decreasing the cost of the product. Finally, the structure variation during the liquid-solid transformation of molten slag should be further researched, contributing to realize the control of the mineral composition of solidified slag.
In China, the annual output of high temperature molten slag is higher than 6×108 t, which has a great value of heat. However, by now, most of heat resource can not be recovered. In this paper, four heat recovery technologies, including dry granulation, chemical method, waste heat utilization of cooling water and production using molten slag as the raw material, were discussed. The key factor for the application of heat recovery technology was the maximum utilization and economic efficiency. To recover heat resource, dry granulation and chemical method were adopted to treat the molten slag with lower content of active materials. Whereas, molten slag containing higher content of active materials needed to be treated without decreasing slag activity. Furthermore, waste heat utilization of cooling water could be adopted according to the actual condition. The difficulties in production using molten slag as the raw material should be overcome, which is beneficial for increasing the quality and decreasing the cost of the product. Finally, the structure variation during the liquid-solid transformation of molten slag should be further researched, contributing to realize the control of the mineral composition of solidified slag.
2020, 38(9): 194-199.
doi: 10.13205/j.hjgc.202009031
Abstract:
The feasibility of the combining geophysical methods with borehole testing to examine the cut-off curtain at a city landfill site was discussed by adopting means of high-density resistivity method, cross-borehole ultrasonic transmission method and borehole television, in the inspection and resorting to multivariate regression in the analysis. The results indicated that high density resistivity method, with its high efficiency, could achieve an overall inspection of the cut-off curtain and delineated suspicious quality defect area. On this basis, cross-borehole ultrasonic transmission method and borehole television, which was intuitive and accurate, could be used to determine the specific characteristic and location of the defects, so as to narrow down the scope of reinforcing. Through multi-scale collocation and multi-parameter verification, this recommended comprehensive method could achieve effective inspection, with different requirements in testing scope and precision of the cut-off curtain.
The feasibility of the combining geophysical methods with borehole testing to examine the cut-off curtain at a city landfill site was discussed by adopting means of high-density resistivity method, cross-borehole ultrasonic transmission method and borehole television, in the inspection and resorting to multivariate regression in the analysis. The results indicated that high density resistivity method, with its high efficiency, could achieve an overall inspection of the cut-off curtain and delineated suspicious quality defect area. On this basis, cross-borehole ultrasonic transmission method and borehole television, which was intuitive and accurate, could be used to determine the specific characteristic and location of the defects, so as to narrow down the scope of reinforcing. Through multi-scale collocation and multi-parameter verification, this recommended comprehensive method could achieve effective inspection, with different requirements in testing scope and precision of the cut-off curtain.
2020, 38(9): 200-207.
doi: 10.13205/j.hjgc.202009032
Abstract:
Land application after being composted is one of the main streams for the input of fluoroquinolone antibiotics into the soil environment. Aerobic composting can effectively remove FQs and reduce the potential environmental risk. However, only few studies have been reported to discuss the factors affecting the removal kinetics of FQs in sewage compost, during different composting phases. In this study, two groups of 56-day incubation were carried out in 0.5 L bioreactors by adding FQs into the compost collected from the mesophilic-phase and thermophilic-phase matrix during aerobic composting of sewage sludge without FQs added. These incubation trials in each group were performed at the different conditions varying at initial FQs content (0, 2.5, 5.0 mg/kg), water contents (50%, 60%, 70%) and aeration rates (0, 15 mL/min), while the temperatures of two-groups treatments were controlled at those corresponding composting phases (mesophilic, 35℃; thermophilic, 55℃). The removal rates of the FQs in the two groups gradually declined when the initial concentration rose, and the optimal initial FQs concentrations for the mesophilic-phase compos were 5.0 mg/kg (OFL) and 2.5 mg/kg (NOR), while 2.5 mg/kg(OFL) for both mesophilic-phase and thermophilic-phase. In the mesophilic-phase compost, the removal rate of FQs increased firstly and then decreased with increasing the water content of the compost from 50% to 70%, and the optimum water content were 60%, while the removal efficiencies of FQs of the thermophilic-phase compost gradually increased with increasing of the water content. In all composts, the ventilation was more conducive to rapidly remove the FQs in sludge compost than no ventilation. Compared with the mesophilic-phase compost, removing FQs in the thermophilic-phase compost needed a lower initial FQs concentration and a higher water content, while in both composts the sufficient ventilation resulting into aerobic environment, more conducive for removal of FQs than no ventilation.
Land application after being composted is one of the main streams for the input of fluoroquinolone antibiotics into the soil environment. Aerobic composting can effectively remove FQs and reduce the potential environmental risk. However, only few studies have been reported to discuss the factors affecting the removal kinetics of FQs in sewage compost, during different composting phases. In this study, two groups of 56-day incubation were carried out in 0.5 L bioreactors by adding FQs into the compost collected from the mesophilic-phase and thermophilic-phase matrix during aerobic composting of sewage sludge without FQs added. These incubation trials in each group were performed at the different conditions varying at initial FQs content (0, 2.5, 5.0 mg/kg), water contents (50%, 60%, 70%) and aeration rates (0, 15 mL/min), while the temperatures of two-groups treatments were controlled at those corresponding composting phases (mesophilic, 35℃; thermophilic, 55℃). The removal rates of the FQs in the two groups gradually declined when the initial concentration rose, and the optimal initial FQs concentrations for the mesophilic-phase compos were 5.0 mg/kg (OFL) and 2.5 mg/kg (NOR), while 2.5 mg/kg(OFL) for both mesophilic-phase and thermophilic-phase. In the mesophilic-phase compost, the removal rate of FQs increased firstly and then decreased with increasing the water content of the compost from 50% to 70%, and the optimum water content were 60%, while the removal efficiencies of FQs of the thermophilic-phase compost gradually increased with increasing of the water content. In all composts, the ventilation was more conducive to rapidly remove the FQs in sludge compost than no ventilation. Compared with the mesophilic-phase compost, removing FQs in the thermophilic-phase compost needed a lower initial FQs concentration and a higher water content, while in both composts the sufficient ventilation resulting into aerobic environment, more conducive for removal of FQs than no ventilation.
2020, 38(9): 208-212,218.
doi: 10.13205/j.hjgc.202009033
Abstract:
In order to explore the effect of CaO pretreatment on anaerobic digestion of vegetation in the ebb-flow zone (VE) for methane production, four kinds of CaO with different mass fractions were used to pretreat VE at medium temperature, and the anaerobic digestibility of VE after CaO pretreatment was investigated. The experimental results showed that CaO pretreatment increased the content of soluble COD in VE, reduced the content of cellulose and lignin, and provided material basis for subsequent digestion process. When CaO dosage was 3%, the maximum methane accumulation was (229.8±6.3) mL/g, which was significantly higher than other groups. In addition, the volume fraction of methane in VE group pretreated with CaO increased with digestion time. CaO could promote the accumulation of volatile fatty acids (VFA). When the dosage of CaO was 3%, the maximum accumulation of VFA was (964±45) mg/L. CaO pretreatment accelerated the reduction of total suspended solids and volatile suspended solids in VE.
In order to explore the effect of CaO pretreatment on anaerobic digestion of vegetation in the ebb-flow zone (VE) for methane production, four kinds of CaO with different mass fractions were used to pretreat VE at medium temperature, and the anaerobic digestibility of VE after CaO pretreatment was investigated. The experimental results showed that CaO pretreatment increased the content of soluble COD in VE, reduced the content of cellulose and lignin, and provided material basis for subsequent digestion process. When CaO dosage was 3%, the maximum methane accumulation was (229.8±6.3) mL/g, which was significantly higher than other groups. In addition, the volume fraction of methane in VE group pretreated with CaO increased with digestion time. CaO could promote the accumulation of volatile fatty acids (VFA). When the dosage of CaO was 3%, the maximum accumulation of VFA was (964±45) mg/L. CaO pretreatment accelerated the reduction of total suspended solids and volatile suspended solids in VE.
2020, 38(9): 213-218.
doi: 10.13205/j.hjgc.202009034
Abstract:
The dry anaerobic fermentation performance of kitchen waste and food waste to produce methane characteristics under mesophilic (35℃) and thermophilic (55℃) condition were studied respectively. The results showed that the cumulative gas production in the thermophilic fermentation were higher than that in 35℃ temperature groups. When the ratio of kitchen waste and food waste was 1:5 in the high temperature group, the cumulative gas production reached the highest level. The maximum cumulative gas production was 2492.5 mL, which was 1.4 times of the production of methane in the medium temperature group. In order to increase the yield of biogas, 4 kinds of activated carbon, such as sugarcane rind, straw, peanut vine and biogas residue, were prepared and the effects of different kinds of activated carbon on anaerobic fermentation were investigated. The experimental results showed that the 4 kinds of activated carbon had honeycomb shaped holes, especially the activated carbon produced from sugarcane rind had relatively higher regular and complete holes, which could provide larger area for microbes and improve the process of gas producing. When sugarcane rind activated carbon was added in the system, the cumulative gas production could reach 3410 mL, 20.1% higher than that of blank group.
The dry anaerobic fermentation performance of kitchen waste and food waste to produce methane characteristics under mesophilic (35℃) and thermophilic (55℃) condition were studied respectively. The results showed that the cumulative gas production in the thermophilic fermentation were higher than that in 35℃ temperature groups. When the ratio of kitchen waste and food waste was 1:5 in the high temperature group, the cumulative gas production reached the highest level. The maximum cumulative gas production was 2492.5 mL, which was 1.4 times of the production of methane in the medium temperature group. In order to increase the yield of biogas, 4 kinds of activated carbon, such as sugarcane rind, straw, peanut vine and biogas residue, were prepared and the effects of different kinds of activated carbon on anaerobic fermentation were investigated. The experimental results showed that the 4 kinds of activated carbon had honeycomb shaped holes, especially the activated carbon produced from sugarcane rind had relatively higher regular and complete holes, which could provide larger area for microbes and improve the process of gas producing. When sugarcane rind activated carbon was added in the system, the cumulative gas production could reach 3410 mL, 20.1% higher than that of blank group.
2020, 38(9): 219-223.
doi: 10.13205/j.hjgc.202009035
Abstract:
In view of the environmental problems caused by the release of a large amount of Mn from the electrolytic manganese slag yard under rainy conditions, in this study, the modification of lignite and sodium humate was carried out, and the modified materials were further combined with chitosan and phenolic resin to investigate the effect of different humic acid materials on the stability of Mn in electrolytic manganese slag. The results showed that when the amount of humic acid material added was 5%~20%, the stability efficiency of Mn in manganese slag was 27.5%~31.5% for lignite, while the stability efficiency of humate to Mn was 7.2%~27.6% (for sodium humate). The Mn stabilization efficiency in manganese slag of the insoluble humic acid, from modified lignite, was up to 14.3%, but the sulfonated humic acid, from modified sodium humate, had a slight improvement. Furthermore, insoluble humic acid and sulfonated sodium humate were compounded with chitosan and phenolic resin respectively, it was concluded that the stability efficiency of Mn in manganese slag was up to 55.7% for chitosan-insoluble humic acid composite; and the stability efficiency of Mn in manganese slag was up to 73.1% for phenolic resin-sulfonated humic acid composite.
In view of the environmental problems caused by the release of a large amount of Mn from the electrolytic manganese slag yard under rainy conditions, in this study, the modification of lignite and sodium humate was carried out, and the modified materials were further combined with chitosan and phenolic resin to investigate the effect of different humic acid materials on the stability of Mn in electrolytic manganese slag. The results showed that when the amount of humic acid material added was 5%~20%, the stability efficiency of Mn in manganese slag was 27.5%~31.5% for lignite, while the stability efficiency of humate to Mn was 7.2%~27.6% (for sodium humate). The Mn stabilization efficiency in manganese slag of the insoluble humic acid, from modified lignite, was up to 14.3%, but the sulfonated humic acid, from modified sodium humate, had a slight improvement. Furthermore, insoluble humic acid and sulfonated sodium humate were compounded with chitosan and phenolic resin respectively, it was concluded that the stability efficiency of Mn in manganese slag was up to 55.7% for chitosan-insoluble humic acid composite; and the stability efficiency of Mn in manganese slag was up to 73.1% for phenolic resin-sulfonated humic acid composite.
2020, 38(9): 224-230.
doi: 10.13205/j.hjgc.202009036
Abstract:
In order to solve the problem of focusing effect in the process of electrokinetic remediation of heavy mental contaminated soil, the electrochemical combined remediation technology at the expense of iron anode was proposed. Based on the traditional electric repair method, the combined remediation technology added the electrolyte purification circulation device and it optimized the technical parameters for the reduction and precipitation of Cr (Ⅵ). The remediation effect and applicability were evaluated by comparing with the traditional electric remediation technology. The results showed that:1) The removed Cr (Ⅵ) can be reduced to Cr (Ⅲ) and precipitated under the action of Fe2+, and the parameters of pH, voltage gradient, current density and electrode area all affected the reaction rate. Electrode distance had no direct impact on the reaction but reflected in the power of electrolysis. 2) The best technical parameters of Cr (Ⅵ) reduction-precipitation reaction were:pH value was 5~6.5, voltage gradient was 0.8 V/cm, current density was more than 6.67 mA/cm2, electrode area was 90 cm2, and electrode distance was 15 cm. 3) Compared with traditional electric remediation technology, the removal rate of different soil points fluctuated in the range of 10%, and the removal rate of highest point was increased by nearly 24% (nearly 93.4%) in the electrochemical combined remediation technology. Especially, the removal rate of chromium near anode increased from 0.24% to 80.38%. 4) The electrochemical combined remediation method based on strengthening by anode consumption could not only solve effectively the focus problem, but also help to promote the overall migration of heavy metal in contaminated soil.
In order to solve the problem of focusing effect in the process of electrokinetic remediation of heavy mental contaminated soil, the electrochemical combined remediation technology at the expense of iron anode was proposed. Based on the traditional electric repair method, the combined remediation technology added the electrolyte purification circulation device and it optimized the technical parameters for the reduction and precipitation of Cr (Ⅵ). The remediation effect and applicability were evaluated by comparing with the traditional electric remediation technology. The results showed that:1) The removed Cr (Ⅵ) can be reduced to Cr (Ⅲ) and precipitated under the action of Fe2+, and the parameters of pH, voltage gradient, current density and electrode area all affected the reaction rate. Electrode distance had no direct impact on the reaction but reflected in the power of electrolysis. 2) The best technical parameters of Cr (Ⅵ) reduction-precipitation reaction were:pH value was 5~6.5, voltage gradient was 0.8 V/cm, current density was more than 6.67 mA/cm2, electrode area was 90 cm2, and electrode distance was 15 cm. 3) Compared with traditional electric remediation technology, the removal rate of different soil points fluctuated in the range of 10%, and the removal rate of highest point was increased by nearly 24% (nearly 93.4%) in the electrochemical combined remediation technology. Especially, the removal rate of chromium near anode increased from 0.24% to 80.38%. 4) The electrochemical combined remediation method based on strengthening by anode consumption could not only solve effectively the focus problem, but also help to promote the overall migration of heavy metal in contaminated soil.
2020, 38(9): 231-235,174.
doi: 10.13205/j.hjgc.202009037
Abstract:
To evaluate the pollution risk of heavy metals (Cr, Cu, Ni, Pb, Zn, As, Hg, Cd) in soil samples from typical petrochemical waste water irrigation areas in Urumqi. According to the results of correlation analysis, we tried to indicate the degree of heavy metal pollution with soil magnetic susceptibility. The results showed that the content of eight kinds of heavy metal in the soil samples did not exceed Soil Environmental Quality-Agricultural Land Soil Pollution Risk Management and Control Standard (Trial) (GB 15681-2018). Except Pb, the other seven kinds of heavy metal content exceeded the background values of Xinjiang farmland soil, especially for As, Hg and Cd. The evaluation results of the Nemero comprehensive index indicated that except for Pb, the other seven heavy metals in the soil samples showed different extents of pollution, and Hg and Cd were the most serious. While according to the geological accumulation index method, Hg, Cd and As were in serious pollution extent. Correlation analysis results showed that there was a certain degree of correlation between soil magnetic susceptibility and heavy metal content, which has a good indicating function.
To evaluate the pollution risk of heavy metals (Cr, Cu, Ni, Pb, Zn, As, Hg, Cd) in soil samples from typical petrochemical waste water irrigation areas in Urumqi. According to the results of correlation analysis, we tried to indicate the degree of heavy metal pollution with soil magnetic susceptibility. The results showed that the content of eight kinds of heavy metal in the soil samples did not exceed Soil Environmental Quality-Agricultural Land Soil Pollution Risk Management and Control Standard (Trial) (GB 15681-2018). Except Pb, the other seven kinds of heavy metal content exceeded the background values of Xinjiang farmland soil, especially for As, Hg and Cd. The evaluation results of the Nemero comprehensive index indicated that except for Pb, the other seven heavy metals in the soil samples showed different extents of pollution, and Hg and Cd were the most serious. While according to the geological accumulation index method, Hg, Cd and As were in serious pollution extent. Correlation analysis results showed that there was a certain degree of correlation between soil magnetic susceptibility and heavy metal content, which has a good indicating function.
2020, 38(9): 236-240,184.
doi: 10.13205/j.hjgc.202009038
Abstract:
In order to investigate the removal capability of heavy metals from soil by microbial fuel cells, we measure the electrical performance of a double-chamber microbial fuel cell (MFCs), and salt bridge was used as the proton channel in MFCs. The concentration of lead(Pb2+) was determined by flame atomic absorption spectrophotometry. The enrichment of Pb on electrode plate was observed by scanning electron microscope and analyzed by energy dispersive spectroscopy. The systematic taxonomic position of the bacteria isolated from the anolyte was analyzed by isolation, purification, 16S rDNA sequencing, and the establishment of the system tree. The results showed that after 10 days of MFCs operation, the removal of lead (Pb2+) from soil was as high as 64.40%, and the maximum voltage was 69.63 mV. The systematic taxonomic position analysis of the bacteria isolated from the anolyte showed that the two bacteria had the highest homology of 100% with Stenotrophomonas maltophilia strain LH15 (KM893074) and Pseudomonas sp. putida strain (MF996382) respectively. Based on the above results, the two strains were defined into Stentrophomonas and Pseudomonas by genus, and named SKD-GYT-1 (LC479453) and SKD-GYT-2 (LC479454) respectively, and their power generation capacity remained to be explored. Soil microbial fuel cells have a high capacity of generating electricity and obvious effect on the removal of lead from soil.
In order to investigate the removal capability of heavy metals from soil by microbial fuel cells, we measure the electrical performance of a double-chamber microbial fuel cell (MFCs), and salt bridge was used as the proton channel in MFCs. The concentration of lead(Pb2+) was determined by flame atomic absorption spectrophotometry. The enrichment of Pb on electrode plate was observed by scanning electron microscope and analyzed by energy dispersive spectroscopy. The systematic taxonomic position of the bacteria isolated from the anolyte was analyzed by isolation, purification, 16S rDNA sequencing, and the establishment of the system tree. The results showed that after 10 days of MFCs operation, the removal of lead (Pb2+) from soil was as high as 64.40%, and the maximum voltage was 69.63 mV. The systematic taxonomic position analysis of the bacteria isolated from the anolyte showed that the two bacteria had the highest homology of 100% with Stenotrophomonas maltophilia strain LH15 (KM893074) and Pseudomonas sp. putida strain (MF996382) respectively. Based on the above results, the two strains were defined into Stentrophomonas and Pseudomonas by genus, and named SKD-GYT-1 (LC479453) and SKD-GYT-2 (LC479454) respectively, and their power generation capacity remained to be explored. Soil microbial fuel cells have a high capacity of generating electricity and obvious effect on the removal of lead from soil.
2020, 38(9): 241-246.
doi: 10.13205/j.hjgc.202009039
Abstract:
In order to explore the effect of sludge biochar on passivation and remediation of Cd-contaminated soil, pot experiments were conducted to simulate the Cd-contaminated soil, and the effect of biochar on pH, organic carbon, Cd content and its valence state, plant height, enrichment coefficient and biotransformation coefficient of Cd-contaminated soil were investigated. The experimental results showed that the biochar prepared at 800℃ had better repair effect than that prepared at 300℃, and the optimum dosage of biochar was 9.0 g/kg. The content of Cd in soil also increased to 7.9 mg/kg at 800℃, which was about 1.0 mg/kg higher than that under 300℃ pyrolysis. Sludge biochar significantly reduced the content of acid extractable and reduced Cd in soil, but increased the content of oxidized and residual Cd. When the pyrolysis temperature was 800℃, the Cd content of acid extractable and reduced state was reduced to 0.68 mg/kg and 0.45 mg/kg, respectively, and the Cd content of oxidation state and residue state was increased to 0.76 mg/kg and 1.72 mg/kg, respectively, thus reduced the content of bioavailable Cd in soil. In addition, biochar could reduce the bioconcentration and transformation coefficients of Cd.
In order to explore the effect of sludge biochar on passivation and remediation of Cd-contaminated soil, pot experiments were conducted to simulate the Cd-contaminated soil, and the effect of biochar on pH, organic carbon, Cd content and its valence state, plant height, enrichment coefficient and biotransformation coefficient of Cd-contaminated soil were investigated. The experimental results showed that the biochar prepared at 800℃ had better repair effect than that prepared at 300℃, and the optimum dosage of biochar was 9.0 g/kg. The content of Cd in soil also increased to 7.9 mg/kg at 800℃, which was about 1.0 mg/kg higher than that under 300℃ pyrolysis. Sludge biochar significantly reduced the content of acid extractable and reduced Cd in soil, but increased the content of oxidized and residual Cd. When the pyrolysis temperature was 800℃, the Cd content of acid extractable and reduced state was reduced to 0.68 mg/kg and 0.45 mg/kg, respectively, and the Cd content of oxidation state and residue state was increased to 0.76 mg/kg and 1.72 mg/kg, respectively, thus reduced the content of bioavailable Cd in soil. In addition, biochar could reduce the bioconcentration and transformation coefficients of Cd.
2020, 38(9): 247-252.
doi: 10.13205/j.hjgc.202009040
Abstract:
In recent years, soil contaminated with mercury (Hg) has become serious problem on earth, endangering the environment and human health. Therefore, it is urgent to develop a reasonable and effective method to remediate it. Some microorganisms have capacity of adsorption and volatilization for Hg(Ⅱ), and can be applied to the bioremediation of Hg-contaminated environments. In this study, a highly Hg-resistant fungus (DC-F9) was isolated from the heavy metal-contaminated soil with a minimum inhibitory concentration (MIC) of 160 mg/L. The strain belonged to the genus Aspergillus by the phylogenetic analysis of its ITS sequence. In the medium supplemented with Hg(Ⅱ) concentration of 5 mg/L, the volatilization rate, adsorption rate and total removal rate of Hg(Ⅱ) were 36.8%, 58.4%, 95.2% respectively; and they were 45.4%, 40.2%, 85.6% respectively at Hg(Ⅱ) concentration of 10 mg/L. The strain exhibited a variety of physiological changes in response to mercury stress by FTIR analyses. These results showed that the DC-F9 had potentials of bioremediation for Hg-contaminated environment.
In recent years, soil contaminated with mercury (Hg) has become serious problem on earth, endangering the environment and human health. Therefore, it is urgent to develop a reasonable and effective method to remediate it. Some microorganisms have capacity of adsorption and volatilization for Hg(Ⅱ), and can be applied to the bioremediation of Hg-contaminated environments. In this study, a highly Hg-resistant fungus (DC-F9) was isolated from the heavy metal-contaminated soil with a minimum inhibitory concentration (MIC) of 160 mg/L. The strain belonged to the genus Aspergillus by the phylogenetic analysis of its ITS sequence. In the medium supplemented with Hg(Ⅱ) concentration of 5 mg/L, the volatilization rate, adsorption rate and total removal rate of Hg(Ⅱ) were 36.8%, 58.4%, 95.2% respectively; and they were 45.4%, 40.2%, 85.6% respectively at Hg(Ⅱ) concentration of 10 mg/L. The strain exhibited a variety of physiological changes in response to mercury stress by FTIR analyses. These results showed that the DC-F9 had potentials of bioremediation for Hg-contaminated environment.
