Login
Register
E-alert
2023 Vol. 41, No. 6
Display Method:
2023, 41(6): 1-8,16.
doi: 10.13205/j.hjgc.202306001
Abstract:
Spartina alterniflora is one of the most harmful alien invasive species in the coastal areas of China. It is of great significance to explore efficient and feasible control technology of S. alterniflora to protect the intertidal ecological environment. Based on the long-term field investigation and in-situ experiments in the Yellow River Delta, this study revealed the efficacies of different control techniques of S. alterniflora. From the middle of June, 2018, 2 to 4 times of mowing (the stubble height was less than 3cm, and the interval between adjacent mowing events was approximately 15 days) could eliminate more than 99% of S. alterniflora, and the control efficacy was still as high as 98.8% at the end of the second growing season. Mowing plus ploughing in mid-December resulted in a controlled efficacy of 99.7% at the end of the second growing season. The tidal flat elevation gradually increased from sea to land, and the environmental factors such as soil's physical and chemical properties changed accordingly. The density, plant height and biomass of S. alterniflora increased first and then decreased with the increase of elevation. Considering the growth characteristics, habitat characteristics of S. alterniflora and the efficacies of different control techniques, a control technology system of S. alterniflora suitable for different tidal flat habitats was summarized. In the low tidal flat, middle tidal flat and high tidal flat, mowing close to the ground, mowing plus waterlogging, and mowing plus tilling were recommended, respectively. For S. alterniflora in river channels or ditches, mowing plus tilling or mowing plus waterlogging were recommended according to the factors, such as the width of the channels or ditches. For S. alterniflora on the ditch slope, mowing plus shading was recommended.
Spartina alterniflora is one of the most harmful alien invasive species in the coastal areas of China. It is of great significance to explore efficient and feasible control technology of S. alterniflora to protect the intertidal ecological environment. Based on the long-term field investigation and in-situ experiments in the Yellow River Delta, this study revealed the efficacies of different control techniques of S. alterniflora. From the middle of June, 2018, 2 to 4 times of mowing (the stubble height was less than 3cm, and the interval between adjacent mowing events was approximately 15 days) could eliminate more than 99% of S. alterniflora, and the control efficacy was still as high as 98.8% at the end of the second growing season. Mowing plus ploughing in mid-December resulted in a controlled efficacy of 99.7% at the end of the second growing season. The tidal flat elevation gradually increased from sea to land, and the environmental factors such as soil's physical and chemical properties changed accordingly. The density, plant height and biomass of S. alterniflora increased first and then decreased with the increase of elevation. Considering the growth characteristics, habitat characteristics of S. alterniflora and the efficacies of different control techniques, a control technology system of S. alterniflora suitable for different tidal flat habitats was summarized. In the low tidal flat, middle tidal flat and high tidal flat, mowing close to the ground, mowing plus waterlogging, and mowing plus tilling were recommended, respectively. For S. alterniflora in river channels or ditches, mowing plus tilling or mowing plus waterlogging were recommended according to the factors, such as the width of the channels or ditches. For S. alterniflora on the ditch slope, mowing plus shading was recommended.
2023, 41(6): 9-16.
doi: 10.13205/j.hjgc.202306002
Abstract:
The article analyzes water and soil erosion, soil desertification, wetland degradation, and human activities in the Yellow River Delta region from 2015 to 2020, based on various satellite remote sensing data and other auxiliary data. The results showed that more than 60% of the area in the Yellow River Delta region has no water and soil erosion, but the phenomenon is more obvious in the farmland areas where the rivers flow through. More than 90% of the region shows mild to moderate soil desertification, and soil desertification was the most severe in 2017. The wetland ecosystem increases, with a total area increase of 91.95 km2, accounting for 10.6% of the total area. The total area of human activities decreases by 152.02 hm2, with a 66.99% reduction in the agricultural development area and a slight increase in mineral resource development. Overall, ecological environment protection and restoration in the Yellow River Delta from 2015 to 2020 have achieved certain results, and the ecological environment has developed positively, but some ecological problems still exist, and the corresponding ecological governance and protection measures should be taken.
The article analyzes water and soil erosion, soil desertification, wetland degradation, and human activities in the Yellow River Delta region from 2015 to 2020, based on various satellite remote sensing data and other auxiliary data. The results showed that more than 60% of the area in the Yellow River Delta region has no water and soil erosion, but the phenomenon is more obvious in the farmland areas where the rivers flow through. More than 90% of the region shows mild to moderate soil desertification, and soil desertification was the most severe in 2017. The wetland ecosystem increases, with a total area increase of 91.95 km2, accounting for 10.6% of the total area. The total area of human activities decreases by 152.02 hm2, with a 66.99% reduction in the agricultural development area and a slight increase in mineral resource development. Overall, ecological environment protection and restoration in the Yellow River Delta from 2015 to 2020 have achieved certain results, and the ecological environment has developed positively, but some ecological problems still exist, and the corresponding ecological governance and protection measures should be taken.
2023, 41(6): 17-22,31.
doi: 10.13205/j.hjgc.202306003
Abstract:
In the treatment of high salt wastewater emitted from the coal chemical industry in the Yellow River basin, the falling film evaporation technology was widely used, due to its advantages of high heat transfer coefficient, short material residence time and high treatment efficiency, but the evaporation process was not effective due to the difference of flow characteristics, which became one of the keys to the near zero discharge treatment of coal chemical industry. In this paper, the differences in falling film flow characteristics of 3% NaCl at different inlet velocities were studied by numerical simulation, and the axial and radial changes of the falling film flow characteristics of 3%, 5% and 7% NaCl were compared. The results showed that the effect of the change in liquid film temperature and liquid volume fraction of saline wastewater (3% NaCl) was more obvious at different inlet velocities, and the smaller the inlet velocity, the more rapid the temperature increased and the liquid volume fraction decreased. At the same inlet velocity, the difference between axial and radial temperature, axial turbulence intensity and axial and radial liquid volume of 3%, 5% and 7% NaCl was not significant, while the axial velocity and radial velocity of saline effluent with high concentration were slightly higher than other components, while the radial turbulence intensity was the opposite.
In the treatment of high salt wastewater emitted from the coal chemical industry in the Yellow River basin, the falling film evaporation technology was widely used, due to its advantages of high heat transfer coefficient, short material residence time and high treatment efficiency, but the evaporation process was not effective due to the difference of flow characteristics, which became one of the keys to the near zero discharge treatment of coal chemical industry. In this paper, the differences in falling film flow characteristics of 3% NaCl at different inlet velocities were studied by numerical simulation, and the axial and radial changes of the falling film flow characteristics of 3%, 5% and 7% NaCl were compared. The results showed that the effect of the change in liquid film temperature and liquid volume fraction of saline wastewater (3% NaCl) was more obvious at different inlet velocities, and the smaller the inlet velocity, the more rapid the temperature increased and the liquid volume fraction decreased. At the same inlet velocity, the difference between axial and radial temperature, axial turbulence intensity and axial and radial liquid volume of 3%, 5% and 7% NaCl was not significant, while the axial velocity and radial velocity of saline effluent with high concentration were slightly higher than other components, while the radial turbulence intensity was the opposite.
2023, 41(6): 23-31.
doi: 10.13205/j.hjgc.202306004
Abstract:
Soil organic carbon is a major carbon pool in tidal wetland ecosystems. By dividing the level of the tidal creek and calculating its morphological characteristic index, the spatial distribution characteristics of the typical tidal creek system were analyzed, taking a typical natural tidal channel as the research object. The spatial distribution characteristics of soil organic carbon were analyzed by geostatistical methods. In addition, the effects of morphological characteristics of the tidal creek on the spatial distribution of soil organic carbon were explored. The results showed that there was obvious spatial heterogeneity in the morphological characteristics of the tidal creek. In the middle tidal flats, the connectivity of the tidal creek network was higher, and the density, curvature and bifurcation ratio were also higher than that in other tidal zones. The tidal creek length gradually increased with the increase of tidal creek development grade, while the tidal creek curvature gradually decreased with the increase of tidal creek development grade. The spatial interpolation results showed that the lowest soil organic carbon in 0 to 10 cm soil layer occurred in the middle tidal flats where tidal creeks were more developed, and within the 10~20 cm soil layer, soil organic carbon showed a gradually increasing trend from sea to land, and showed a strip-shaped spatial distribution choracteristic. In the low tidal flats, the mean value of soil organic carbon in a third-order creek was significantly greater than that in a first-order creek. In the middle tidal flats, the mean value of soil organic carbon in a second-order creek was significantly greater than that in a third-order and a first-order creek. The soil organic carbon of the high tide flats was not significantly correlated with the tide creek development level. Within the 0 to 10 cm soil layer, the soil organic carbon gradually increased with increasing distance to the tidal creek in low and middle tidal flats. Within the 10 to 20 cm soil layer, the soil organic carbon gradually decreased with increasing distance to tidal creek in the middle tidal flats. However, there was no correlation between the soil organic carbon and the distance to the tidal creek in high tidal flats. The spatial heterogeneity in the morphological characteristics of the tidal creek was one of the important factors of spatial differences in soil organic carbon content in the tidal wetland. Therefore, morphology changes in tidal creeks should be considered in order to accurately estimate the soil carbon pools in tidal wetlands.
Soil organic carbon is a major carbon pool in tidal wetland ecosystems. By dividing the level of the tidal creek and calculating its morphological characteristic index, the spatial distribution characteristics of the typical tidal creek system were analyzed, taking a typical natural tidal channel as the research object. The spatial distribution characteristics of soil organic carbon were analyzed by geostatistical methods. In addition, the effects of morphological characteristics of the tidal creek on the spatial distribution of soil organic carbon were explored. The results showed that there was obvious spatial heterogeneity in the morphological characteristics of the tidal creek. In the middle tidal flats, the connectivity of the tidal creek network was higher, and the density, curvature and bifurcation ratio were also higher than that in other tidal zones. The tidal creek length gradually increased with the increase of tidal creek development grade, while the tidal creek curvature gradually decreased with the increase of tidal creek development grade. The spatial interpolation results showed that the lowest soil organic carbon in 0 to 10 cm soil layer occurred in the middle tidal flats where tidal creeks were more developed, and within the 10~20 cm soil layer, soil organic carbon showed a gradually increasing trend from sea to land, and showed a strip-shaped spatial distribution choracteristic. In the low tidal flats, the mean value of soil organic carbon in a third-order creek was significantly greater than that in a first-order creek. In the middle tidal flats, the mean value of soil organic carbon in a second-order creek was significantly greater than that in a third-order and a first-order creek. The soil organic carbon of the high tide flats was not significantly correlated with the tide creek development level. Within the 0 to 10 cm soil layer, the soil organic carbon gradually increased with increasing distance to the tidal creek in low and middle tidal flats. Within the 10 to 20 cm soil layer, the soil organic carbon gradually decreased with increasing distance to tidal creek in the middle tidal flats. However, there was no correlation between the soil organic carbon and the distance to the tidal creek in high tidal flats. The spatial heterogeneity in the morphological characteristics of the tidal creek was one of the important factors of spatial differences in soil organic carbon content in the tidal wetland. Therefore, morphology changes in tidal creeks should be considered in order to accurately estimate the soil carbon pools in tidal wetlands.
2023, 41(6): 32-37,70.
doi: 10.13205/j.hjgc.202306005
Abstract:
To investigate the effect of microbial electrolysis cells on the nitrification and denitrification performance of constructed wetlands, vertical flow constructed wetland-microbial electrolysis cell systems with closed circuit operation (VFCW-MEC) and open circuit operation (VFCW-C) were constructed. The nitrogen removal performance and N2O emission characteristics of the coupled wetland systems with different external voltages (0, 0.2, 0.4 V) were investigated. The results showed that NH4-N and TN removal efficiencies of VFCW-MEC were higher than that of VFCW-C, and the NH4-N removal efficiencies of VFCW-MEC at external voltages of 0, 0.2, 0.4 V were (61.66±0.30)%, (69.21±0.31)% and (74.82±0.27)%, respectively, and the corresponding values for TN were (11.53±0.35)%, (20.06±0.59)% and (33.29±0.35)%, respectively. These observations indicated that the external voltage can enhance the NH4+-N and TN removal efficiency of the wetland system. By analysing the variation patterns of nitrogen concentration in the anode and cathode zones of the VFCW-MEC system, it was found that the anode and cathode enhanced nitrification and denitrification efficiencies, respectively. Microbial hydrogen production and direct electron transfer contributed to the enhanced denitrification efficiency in the cathode. It is worth that the external voltage increases the efficiency of N2O emission, which is not conducive to greenhouse gas reduction. These findings show the potential of microbial electrolytic cells for enhancing nitrogen removal of constructed wetlands.
To investigate the effect of microbial electrolysis cells on the nitrification and denitrification performance of constructed wetlands, vertical flow constructed wetland-microbial electrolysis cell systems with closed circuit operation (VFCW-MEC) and open circuit operation (VFCW-C) were constructed. The nitrogen removal performance and N2O emission characteristics of the coupled wetland systems with different external voltages (0, 0.2, 0.4 V) were investigated. The results showed that NH4-N and TN removal efficiencies of VFCW-MEC were higher than that of VFCW-C, and the NH4-N removal efficiencies of VFCW-MEC at external voltages of 0, 0.2, 0.4 V were (61.66±0.30)%, (69.21±0.31)% and (74.82±0.27)%, respectively, and the corresponding values for TN were (11.53±0.35)%, (20.06±0.59)% and (33.29±0.35)%, respectively. These observations indicated that the external voltage can enhance the NH4+-N and TN removal efficiency of the wetland system. By analysing the variation patterns of nitrogen concentration in the anode and cathode zones of the VFCW-MEC system, it was found that the anode and cathode enhanced nitrification and denitrification efficiencies, respectively. Microbial hydrogen production and direct electron transfer contributed to the enhanced denitrification efficiency in the cathode. It is worth that the external voltage increases the efficiency of N2O emission, which is not conducive to greenhouse gas reduction. These findings show the potential of microbial electrolytic cells for enhancing nitrogen removal of constructed wetlands.
2023, 41(6): 38-46.
doi: 10.13205/j.hjgc.202306006
Abstract:
The Yellow River Basin is China's important ecological barrier and economic zone. The comprehensive utilization of solid waste has a significant synergy effect on saving resources and reducing carbon emissions, and at the same time can ensure the ecological environment protection and high-quality sustainable development of the Yellow River basin. Therefore, using solid waste for mineral storage is an economical and feasible carbon capture and storage technology. This study used blast furnace slag as the raw material, CaO as an alkali activator, and sodium dodecyl sulfate (C12H25NaO4S, SDS) as a foaming agent to prepare porous materials with high porosity. The optimum preparation conditions of porous materials were obtained as follows:the water-cement ratio was 0.65, alkali activation amount was 12%, and foam content was 6.10%). The porous material prepared under the optimal process conditions can achieve 91.90 kg/m3 CO2 storage performance, and the actual storage capacity is basically consistent with the theoretical prediction value of 89.39 kg/m3. This study can provide a reference for the feasibility of applying alkaline solid waste materials in the carbon storage field.
The Yellow River Basin is China's important ecological barrier and economic zone. The comprehensive utilization of solid waste has a significant synergy effect on saving resources and reducing carbon emissions, and at the same time can ensure the ecological environment protection and high-quality sustainable development of the Yellow River basin. Therefore, using solid waste for mineral storage is an economical and feasible carbon capture and storage technology. This study used blast furnace slag as the raw material, CaO as an alkali activator, and sodium dodecyl sulfate (C12H25NaO4S, SDS) as a foaming agent to prepare porous materials with high porosity. The optimum preparation conditions of porous materials were obtained as follows:the water-cement ratio was 0.65, alkali activation amount was 12%, and foam content was 6.10%). The porous material prepared under the optimal process conditions can achieve 91.90 kg/m3 CO2 storage performance, and the actual storage capacity is basically consistent with the theoretical prediction value of 89.39 kg/m3. This study can provide a reference for the feasibility of applying alkaline solid waste materials in the carbon storage field.
2023, 41(6): 47-53,156.
doi: 10.13205/j.hjgc.202306007
Abstract:
Rural domestic sewage treatment (i.e. RDST) is of great significance for promoting ecological protection and high-quality development of the Yellow River Basin. Taking the counties in the Yellow River Basin as the basic statistical units, the rates of RDST in the counties were calculated, and the following problems were found. 1) The RDST was unbalanced in overall progress and varied significantly among the Yellow River Basin's upper, middle, and lower reaches. 2) In terms of the population concentrated areas, the rates of RDST were low in some areas of Henan. 3) RDST of township government residents, and central villages had not been fully covered. 4) The RDST level of the key river basins was low, including the Wuliangsuhai Lake, and the Sushui River. Finally, the unclear connotation and implementation way of Resource Utilization led to the possibility of inflated RDST in the upper and middle reaches of the Yellow River Basin. Therefore, to promote the RDST of the Yellow River Basin in the 14th Five-Year Plan, we should identify the bull's eye to highlight key points. 1) Accurate treatment areas are required, including the areas with low rates of RDST, and the Wuliangsuhai Lake, Sushui River and other key river basins. 2) Accurate measures are required. The collaborative treatment of the rural domestic sewage and water environment should be highlighted, thus striving to solve prominent pollution problems of water. 3) Accurate assistance is required based on the characteristics of the upper, middle, and lower reaches of the Yellow River Basin. The definition and implementation path of Resource Utilization should be further clarified.
Rural domestic sewage treatment (i.e. RDST) is of great significance for promoting ecological protection and high-quality development of the Yellow River Basin. Taking the counties in the Yellow River Basin as the basic statistical units, the rates of RDST in the counties were calculated, and the following problems were found. 1) The RDST was unbalanced in overall progress and varied significantly among the Yellow River Basin's upper, middle, and lower reaches. 2) In terms of the population concentrated areas, the rates of RDST were low in some areas of Henan. 3) RDST of township government residents, and central villages had not been fully covered. 4) The RDST level of the key river basins was low, including the Wuliangsuhai Lake, and the Sushui River. Finally, the unclear connotation and implementation way of Resource Utilization led to the possibility of inflated RDST in the upper and middle reaches of the Yellow River Basin. Therefore, to promote the RDST of the Yellow River Basin in the 14th Five-Year Plan, we should identify the bull's eye to highlight key points. 1) Accurate treatment areas are required, including the areas with low rates of RDST, and the Wuliangsuhai Lake, Sushui River and other key river basins. 2) Accurate measures are required. The collaborative treatment of the rural domestic sewage and water environment should be highlighted, thus striving to solve prominent pollution problems of water. 3) Accurate assistance is required based on the characteristics of the upper, middle, and lower reaches of the Yellow River Basin. The definition and implementation path of Resource Utilization should be further clarified.
2023, 41(6): 54-61.
doi: 10.13205/j.hjgc.202306008
Abstract:
Carrying out ecological protection and restoration of mountain-river-forest-farmland-lake-grassland is not only an important part of optimizing the ecological pattern and stabilizing the ecosystem and a powerful initiative to omnidirectionally implement the ecological civilization construction, but also an inevitable requirement to realize the harmonious coexistence between man and nature. This study is based on the theory of mountain-river-forest-farmland-lake-grass land system governance, identifying areas to highlight ecological environmental problems, formulating objectives for ecological protection and restoration, and proposing specific ecological protection and restoration governance schemes. In this paper, the ecological protection and restoration project of mountain-river-forest-farmland-lake-grassland in the old course of the Yellow River-the northern plain in Henan Province was taken as an example. Through current situation analysis and field investigation, the prominent ecological environment problems in the region were figured out, such as serious land degradation and soil pollution, water pollution and ecological environment deterioration in the river basin. The idea of One Line, One Belt and Three Districts for overall control was proposed, focusing on managing 494 ecological construction projects in five categories, including land remediation and soil pollution degradation, river basin water ecological environment restoration and control, mine ecological environment restoration, water and soil erosion control, to finally achieve comprehensive management of mountain-river-forest-farmland-lake-grassland in whole. Through the implementation of the ecological protection and restoration scheme, the service function of the regional ecosystem was improved and the high-quality development of the Yellow River Basin was promoted, which provided a reference for the practice of ecological protection and restoration of mountain-river-forest-farm land-lake-grassland in Henan Province.
Carrying out ecological protection and restoration of mountain-river-forest-farmland-lake-grassland is not only an important part of optimizing the ecological pattern and stabilizing the ecosystem and a powerful initiative to omnidirectionally implement the ecological civilization construction, but also an inevitable requirement to realize the harmonious coexistence between man and nature. This study is based on the theory of mountain-river-forest-farmland-lake-grass land system governance, identifying areas to highlight ecological environmental problems, formulating objectives for ecological protection and restoration, and proposing specific ecological protection and restoration governance schemes. In this paper, the ecological protection and restoration project of mountain-river-forest-farmland-lake-grassland in the old course of the Yellow River-the northern plain in Henan Province was taken as an example. Through current situation analysis and field investigation, the prominent ecological environment problems in the region were figured out, such as serious land degradation and soil pollution, water pollution and ecological environment deterioration in the river basin. The idea of One Line, One Belt and Three Districts for overall control was proposed, focusing on managing 494 ecological construction projects in five categories, including land remediation and soil pollution degradation, river basin water ecological environment restoration and control, mine ecological environment restoration, water and soil erosion control, to finally achieve comprehensive management of mountain-river-forest-farmland-lake-grassland in whole. Through the implementation of the ecological protection and restoration scheme, the service function of the regional ecosystem was improved and the high-quality development of the Yellow River Basin was promoted, which provided a reference for the practice of ecological protection and restoration of mountain-river-forest-farm land-lake-grassland in Henan Province.
2023, 41(6): 62-70.
doi: 10.13205/j.hjgc.202306009
Abstract:
The early hydration kinetics of cementitious filling materials is an important prerequisite for reasonable designed ratios. In this paper, the early hydration exothermic condition of fly ash paste filling materials (FPFM) with different CaCl2 concentration excitation was measured by isothermal calorimetry, and the early hydration exothermic heat of different FPFM was fitted based on the Krstulovic-Dabic hydration kinetic model. The hydration kinetic parameters were calculated, the variation characteristics of each stage of the hydration dynamic process were analyzed, and the excitation mechanism of CaCl2 was explained. The results showed that with the increase of CaCl2 concentration, the hydration heat of FPFM increased from 1.1 mW/g to 2.9 mW/g, and the total cumulative heat release increased from 16.4 J/g to 29.6 J/g, so that the hydration reaction rate was accelerated and the degree of hydration reaction was deepened. The hydration mechanism of FPFM stimulated by CaCl2 was NG→I→D, and with the increase of CaCl2 concentration, the kinetic parameters of FPFM were increased, and the duration of phase I was prolonged, which promoted the pozzarash reaction of fly ash and produced more hydration products. Therefore, through the study of the early hydration kinetic characteristics of CaCl2 exciting FPFM, the law of its structural evolution is revealed, which provides a certain guide for the application of FPFM.
The early hydration kinetics of cementitious filling materials is an important prerequisite for reasonable designed ratios. In this paper, the early hydration exothermic condition of fly ash paste filling materials (FPFM) with different CaCl2 concentration excitation was measured by isothermal calorimetry, and the early hydration exothermic heat of different FPFM was fitted based on the Krstulovic-Dabic hydration kinetic model. The hydration kinetic parameters were calculated, the variation characteristics of each stage of the hydration dynamic process were analyzed, and the excitation mechanism of CaCl2 was explained. The results showed that with the increase of CaCl2 concentration, the hydration heat of FPFM increased from 1.1 mW/g to 2.9 mW/g, and the total cumulative heat release increased from 16.4 J/g to 29.6 J/g, so that the hydration reaction rate was accelerated and the degree of hydration reaction was deepened. The hydration mechanism of FPFM stimulated by CaCl2 was NG→I→D, and with the increase of CaCl2 concentration, the kinetic parameters of FPFM were increased, and the duration of phase I was prolonged, which promoted the pozzarash reaction of fly ash and produced more hydration products. Therefore, through the study of the early hydration kinetic characteristics of CaCl2 exciting FPFM, the law of its structural evolution is revealed, which provides a certain guide for the application of FPFM.
2023, 41(6): 71-75,91.
doi: 10.13205/j.hjgc.202306010
Abstract:
Compared with the conventional treatment methods of sludge, the thermal alkali decomposition treatment was a preferred technology because of the high value-added protein products obtained. In this investigation, the mixture material from thermal alkali pretreatment was taken as the raw material, and variables including ultrasonic and chemical addition were investigated. Results showed that, the optimal ultrasonic power, time, initial temperature, pH and the ratio of phenol to DNA extraction reagent were 480 W, 20 min, 38℃, 7.83 and 6%, respectively. Under this condition, the protein dissolution reached 861.71 mg/L, 150% to 200% higher than the control groups. Correlation analysis suggested that except for the ultrasonic time, the effects of other factors on sludge protein concentration were extremely significant. Moreover, the addition of DNA extraction phenol reagent could desorb carbohydrates and proteins inside and outside the cell, and further increase the protein concentration to 861.71 mg/L in the filtrate with the 6% dosage.
Compared with the conventional treatment methods of sludge, the thermal alkali decomposition treatment was a preferred technology because of the high value-added protein products obtained. In this investigation, the mixture material from thermal alkali pretreatment was taken as the raw material, and variables including ultrasonic and chemical addition were investigated. Results showed that, the optimal ultrasonic power, time, initial temperature, pH and the ratio of phenol to DNA extraction reagent were 480 W, 20 min, 38℃, 7.83 and 6%, respectively. Under this condition, the protein dissolution reached 861.71 mg/L, 150% to 200% higher than the control groups. Correlation analysis suggested that except for the ultrasonic time, the effects of other factors on sludge protein concentration were extremely significant. Moreover, the addition of DNA extraction phenol reagent could desorb carbohydrates and proteins inside and outside the cell, and further increase the protein concentration to 861.71 mg/L in the filtrate with the 6% dosage.
2023, 41(6): 76-81,108.
doi: 10.13205/j.hjgc.202306011
Abstract:
To study the possibility of simultaneous dewatering and decontamination of dredged sediment by electro-Fenton, an electro-Fenton experimental (EF) device was constructed with self-produced hydrogen peroxide carbon black modified carbon felt (CB-CF) as the cathode, and dimensionally stable Ti/RuO2-IrO2 electrode anode (DSA) as the anode. In this EF device, the effects of Fe2+ dosage, initial pH value, and initial current density on water content and organic matter content of dredging sediment were conducted. The experiment results showed that under the condition of Fe2+was 2 mmol/L, the initial current was 100 mA, and the initial pH value was 7, the degradation rate of organic matter content reached 53.9%, and the water content of dredging sediment reached 26% after 12 h. This study proved that the electro-Fenton method can achieve a good dehydration effect, as well as reduce organic pollutants contents in dredged sediment, which is a process worth exploring for the reduction and harmless of the dredged sediment.
To study the possibility of simultaneous dewatering and decontamination of dredged sediment by electro-Fenton, an electro-Fenton experimental (EF) device was constructed with self-produced hydrogen peroxide carbon black modified carbon felt (CB-CF) as the cathode, and dimensionally stable Ti/RuO2-IrO2 electrode anode (DSA) as the anode. In this EF device, the effects of Fe2+ dosage, initial pH value, and initial current density on water content and organic matter content of dredging sediment were conducted. The experiment results showed that under the condition of Fe2+was 2 mmol/L, the initial current was 100 mA, and the initial pH value was 7, the degradation rate of organic matter content reached 53.9%, and the water content of dredging sediment reached 26% after 12 h. This study proved that the electro-Fenton method can achieve a good dehydration effect, as well as reduce organic pollutants contents in dredged sediment, which is a process worth exploring for the reduction and harmless of the dredged sediment.
2023, 41(6): 82-91.
doi: 10.13205/j.hjgc.202306012
Abstract:
The thermal stability and material transformation characteristics of organic waste treated by vermicomposting were investigated with campus kitchen waste assisted by campus green waste, wasted paper and sawdust. The results indicated that vermicomposting with kitchen waste, leaves and waste paper (1:1:1, by dry weight) with a vermicomposting cycle of 10 weeks, gained better organic stabilization and resource recovery effect. Furthermore, the thermogravimetric analysis showed that the weight loss of the heap decreased from 71.44% to 41.44% after vermicomposting, and the stability of vermicompost was enhanced. Additionally, the kinetic model deduced that the activation energy of the composting group decreased by 6.163 kJ/mol after vermicomposting, indicating that the composting process was accelerated. Humic acid and protein content increased by 20.13% and 17.3% after composting. The content of available nitrogen and available phosphorus in vermicompost increased by 6.54 times and 1.82 times, respectively, after vermicomposting. The vermicomposting treatment of campus kitchen waste, green waste and waste paper effectively accelerated the composting process, improved the degree of organic stabilization and resource utilization, and has the potential in realizing onsite treatment of campus organic wastes.
The thermal stability and material transformation characteristics of organic waste treated by vermicomposting were investigated with campus kitchen waste assisted by campus green waste, wasted paper and sawdust. The results indicated that vermicomposting with kitchen waste, leaves and waste paper (1:1:1, by dry weight) with a vermicomposting cycle of 10 weeks, gained better organic stabilization and resource recovery effect. Furthermore, the thermogravimetric analysis showed that the weight loss of the heap decreased from 71.44% to 41.44% after vermicomposting, and the stability of vermicompost was enhanced. Additionally, the kinetic model deduced that the activation energy of the composting group decreased by 6.163 kJ/mol after vermicomposting, indicating that the composting process was accelerated. Humic acid and protein content increased by 20.13% and 17.3% after composting. The content of available nitrogen and available phosphorus in vermicompost increased by 6.54 times and 1.82 times, respectively, after vermicomposting. The vermicomposting treatment of campus kitchen waste, green waste and waste paper effectively accelerated the composting process, improved the degree of organic stabilization and resource utilization, and has the potential in realizing onsite treatment of campus organic wastes.
2023, 41(6): 92-100.
doi: 10.13205/j.hjgc.202306013
Abstract:
Because of the high salinity and complex composition, high-salt landfill leachate has a strong inhibitory effect on microorganisms, which is difficult to treat directly by traditional biotechnologies. This study used modified basalt fiber (MBF) as the carrier media to construct a new biological contact oxidation reactor, and comprehensively evaluated the treatment effect of the formed biological nest on high-salt wastewater. The results showed that the average removal efficiencies of COD, NH4+-N, TN and TP were (26.3±12.4)%, (29.4±8.8)%, (27.6±7.6)% and (16.5±10.4)%, respectively, for raw wastewater. After gradient dilution, the removal efficiency was increased to (43.7±11.6)%, (59.5±21.4)%, (57.1±12.2)% and (26±8.2)% under a dilution ratio of 1:16; and after treatment, the B/C ratio of wastewater increased from 0.08 to 0.36. In addition, the high-salinity wastewater also promoted the microorganisms to secrete more extracellular polymeric substances (EPS), whose content increased from 231.6 mg/g VSS to 417.5 mg/g VSS under the raw water condition and a dilution ratio of 1:16. The analysis of microbial population structure showed that Halomonas, as an aerobic nitrifying hetero-denitrifying bacteria, has a higher relative abundance with a low dilution ratio, and it decreased with the decrease of salinity. Through the annotation of functional genes, it was found that salinity mainly inhibited the growth of ammonia-oxidizing bacteria (AOB), and the expression of amoABC and hao was not detected in R-1, R-2 and R-3 reactors. Furthermore, the expression of denitrification functional enzymes was also repressed compared with the seed sludge. This study showed that MBF bio-nests were resistant to high-salinity stress, which provides a basis for its application in the biological treatment of high-salinity industrial landfill leachate.
Because of the high salinity and complex composition, high-salt landfill leachate has a strong inhibitory effect on microorganisms, which is difficult to treat directly by traditional biotechnologies. This study used modified basalt fiber (MBF) as the carrier media to construct a new biological contact oxidation reactor, and comprehensively evaluated the treatment effect of the formed biological nest on high-salt wastewater. The results showed that the average removal efficiencies of COD, NH4+-N, TN and TP were (26.3±12.4)%, (29.4±8.8)%, (27.6±7.6)% and (16.5±10.4)%, respectively, for raw wastewater. After gradient dilution, the removal efficiency was increased to (43.7±11.6)%, (59.5±21.4)%, (57.1±12.2)% and (26±8.2)% under a dilution ratio of 1:16; and after treatment, the B/C ratio of wastewater increased from 0.08 to 0.36. In addition, the high-salinity wastewater also promoted the microorganisms to secrete more extracellular polymeric substances (EPS), whose content increased from 231.6 mg/g VSS to 417.5 mg/g VSS under the raw water condition and a dilution ratio of 1:16. The analysis of microbial population structure showed that Halomonas, as an aerobic nitrifying hetero-denitrifying bacteria, has a higher relative abundance with a low dilution ratio, and it decreased with the decrease of salinity. Through the annotation of functional genes, it was found that salinity mainly inhibited the growth of ammonia-oxidizing bacteria (AOB), and the expression of amoABC and hao was not detected in R-1, R-2 and R-3 reactors. Furthermore, the expression of denitrification functional enzymes was also repressed compared with the seed sludge. This study showed that MBF bio-nests were resistant to high-salinity stress, which provides a basis for its application in the biological treatment of high-salinity industrial landfill leachate.
EFFECT OF REDOX CONDITION AND MICROBIAL ACTION ON HEAVY METALS TRANSFORMATION IN RESERVOIR SEDIMENTS
2023, 41(6): 101-108.
doi: 10.13205/j.hjgc.202306014
Abstract:
In order to explore the migration and transformation mechanism of heavy metals between sediment and water interface, we took the surface sediment of a reservoir in Northwest China as the research object. By controlling redox conditions, an indoor simulation experiment was designed including heat sterilization and adding carbon sources to the sediments. It was found that after 28 days of aerobic cultivation, the concentration of six heavy metals in the overlying water decreased by 46.3%~100%, and the total content of heavy metals in the sediment all increased; the content of active form of the six heavy metals decreased, and the content of residual form increased, especially the ratio of residual form content to total amount of Cd and Pb (R/T) increased by 33.32% and 16.11% respectively, compared with the original sample; under anaerobic condition, the trend of concentration change was opposite, and the concentration of Pb in the overlying water was 2.36 times higher than the initial one. Under the action of microorganisms, the concentration of six heavy metals in the overlying water was lower than that of the high-temperature sterilization treatment, while the total amount of heavy metals in the sediment was increased. At the same time, the R/T values of six heavy metals, after adding carbon source, were higher than those of sterilization treatment. This indicated that microbial activity can immobilize heavy metals, causing them to migrate from overlying water to sediments, and converting active states into low-risk residual states, thereby reducing the toxicity of heavy metals to human health. Therefore, increasing the dissolved oxygen content and microbial population in reservoirs played an important role in reducing the activity of heavy metals in sediments, enriching and fixing heavy metals.
In order to explore the migration and transformation mechanism of heavy metals between sediment and water interface, we took the surface sediment of a reservoir in Northwest China as the research object. By controlling redox conditions, an indoor simulation experiment was designed including heat sterilization and adding carbon sources to the sediments. It was found that after 28 days of aerobic cultivation, the concentration of six heavy metals in the overlying water decreased by 46.3%~100%, and the total content of heavy metals in the sediment all increased; the content of active form of the six heavy metals decreased, and the content of residual form increased, especially the ratio of residual form content to total amount of Cd and Pb (R/T) increased by 33.32% and 16.11% respectively, compared with the original sample; under anaerobic condition, the trend of concentration change was opposite, and the concentration of Pb in the overlying water was 2.36 times higher than the initial one. Under the action of microorganisms, the concentration of six heavy metals in the overlying water was lower than that of the high-temperature sterilization treatment, while the total amount of heavy metals in the sediment was increased. At the same time, the R/T values of six heavy metals, after adding carbon source, were higher than those of sterilization treatment. This indicated that microbial activity can immobilize heavy metals, causing them to migrate from overlying water to sediments, and converting active states into low-risk residual states, thereby reducing the toxicity of heavy metals to human health. Therefore, increasing the dissolved oxygen content and microbial population in reservoirs played an important role in reducing the activity of heavy metals in sediments, enriching and fixing heavy metals.
2023, 41(6): 109-116.
doi: 10.13205/j.hjgc.202306015
Abstract:
Aiming at the design and optimization problem of gap height of base slot in the internal components of the biofluidized bed, the effects of different aeration intensities and different gap heights on liquid phase velocity, turbulent kinetic energy and oxygen mass transfer characteristics of biofluidized beds were analyzed by applying laser particle image velocity (PIV) and dissolved oxygen online testing techniques. The result showed that the bottom liquid velocity and the overall liquid velocity of the fluidized bed were maximum when the gap height was 75 mm, and the overall liquid phase turbulent kinetic energy was relatively smaller. Morever, there were small disadvantages in oxygen mass transfer coefficient and mass transfer efficiency. From the perspective of structural optimization, the overall effect was the best when the baffle had a low clearance height of 75 mm, which was conducive to saving energy consumption and reducing cost. In addition, the optimal liquid phase flow field and oxygen mass transfer characteristics, and a more comprehensive and in-depth analysis of the synergy of other internal components of the biological fluidized bed were still required.
Aiming at the design and optimization problem of gap height of base slot in the internal components of the biofluidized bed, the effects of different aeration intensities and different gap heights on liquid phase velocity, turbulent kinetic energy and oxygen mass transfer characteristics of biofluidized beds were analyzed by applying laser particle image velocity (PIV) and dissolved oxygen online testing techniques. The result showed that the bottom liquid velocity and the overall liquid velocity of the fluidized bed were maximum when the gap height was 75 mm, and the overall liquid phase turbulent kinetic energy was relatively smaller. Morever, there were small disadvantages in oxygen mass transfer coefficient and mass transfer efficiency. From the perspective of structural optimization, the overall effect was the best when the baffle had a low clearance height of 75 mm, which was conducive to saving energy consumption and reducing cost. In addition, the optimal liquid phase flow field and oxygen mass transfer characteristics, and a more comprehensive and in-depth analysis of the synergy of other internal components of the biological fluidized bed were still required.
2023, 41(6): 117-123,150.
doi: 10.13205/j.hjgc.202306016
Abstract:
Schwertmannite (Sch) presents high catalytic properties potential for phenol oxidation in a Fenton-like mechanism, because of its unique combination of Fe composition and structure characteristics. In this study, Sch was fabricated as a heterogeneous Fenton-like catalyst through chemical oxidation, for phenol degradation in polluted water and soil. The synthetic minerals have a typical sea-urchin-like structure and ordered morphology with unique channels of a specific size range. The catalytic performance of Sch for phenol oxidation in water and alcohol with various pH values was investigated. Under an acidic pH, nearly 98% of phenol was successfully removed. When Sch material was added to neutral or nearly acidic C6H5OH contaminated soil at a mass ratio of 1.25% or 2.5%, the concentration of C6H5OH could be reduced from 6.052 mg/kg to less than 0.2 mg/kg. The material had great potential application prospect in actual remediation projects of phenol polluted soil.
Schwertmannite (Sch) presents high catalytic properties potential for phenol oxidation in a Fenton-like mechanism, because of its unique combination of Fe composition and structure characteristics. In this study, Sch was fabricated as a heterogeneous Fenton-like catalyst through chemical oxidation, for phenol degradation in polluted water and soil. The synthetic minerals have a typical sea-urchin-like structure and ordered morphology with unique channels of a specific size range. The catalytic performance of Sch for phenol oxidation in water and alcohol with various pH values was investigated. Under an acidic pH, nearly 98% of phenol was successfully removed. When Sch material was added to neutral or nearly acidic C6H5OH contaminated soil at a mass ratio of 1.25% or 2.5%, the concentration of C6H5OH could be reduced from 6.052 mg/kg to less than 0.2 mg/kg. The material had great potential application prospect in actual remediation projects of phenol polluted soil.
2023, 41(6): 124-131,186.
doi: 10.13205/j.hjgc.202306017
Abstract:
To explore the effects of hyperthermophilic pretreatment on the maturity and bacterial community of putrescible waste composting, using putrescible waste and straw as raw materials, two treatments were set up:conventional composting (CC) and hyperthermophilic pretreatment composting (HPC, 4 h, 85℃). Compost was carried out using a laboratory-made hyperthermophilic pretreatment reactor and a composting reactor. After hyperthermophilic pretreatment, the contents of amino acid and reducing sugar in the HPC group increased by 34.2% and 52.9%. The results showed that both groups could get mature within 16 days (C/N<18, GI>70%), and hyperthermophilic pretreatment could increase the temperature of the compost pile in advance, prolong the high-temperature period and improve the maturity. Compared with the CC group, the HPC group had a 40.7% increase in temperature accumulation, a 35% increase in seed germination index, and a 40.2% increase in the humification index, at the end of composting. Lactobacillus was the dominant genus during the initial phase of composting, Bacillus was the dominant genus during the thermophilic phase, and Thermobifida was the relatively dominant genus during the maturation phase. Hyperthermophilic pretreatment was beneficial to the enrichment of thermophilic bacterial communities, especially Bacillus. The relative abundance of Bacillus in the initial phase of composting in the HPC group reached 63%, which was conducive to the consumption of organic matter and temperature rise during composting. In the maturation phase of composting, due to the degradation of organic matter, the bacterial community was stimulated to evolve from the function of degrading organic matter to promoting compost maturity.
To explore the effects of hyperthermophilic pretreatment on the maturity and bacterial community of putrescible waste composting, using putrescible waste and straw as raw materials, two treatments were set up:conventional composting (CC) and hyperthermophilic pretreatment composting (HPC, 4 h, 85℃). Compost was carried out using a laboratory-made hyperthermophilic pretreatment reactor and a composting reactor. After hyperthermophilic pretreatment, the contents of amino acid and reducing sugar in the HPC group increased by 34.2% and 52.9%. The results showed that both groups could get mature within 16 days (C/N<18, GI>70%), and hyperthermophilic pretreatment could increase the temperature of the compost pile in advance, prolong the high-temperature period and improve the maturity. Compared with the CC group, the HPC group had a 40.7% increase in temperature accumulation, a 35% increase in seed germination index, and a 40.2% increase in the humification index, at the end of composting. Lactobacillus was the dominant genus during the initial phase of composting, Bacillus was the dominant genus during the thermophilic phase, and Thermobifida was the relatively dominant genus during the maturation phase. Hyperthermophilic pretreatment was beneficial to the enrichment of thermophilic bacterial communities, especially Bacillus. The relative abundance of Bacillus in the initial phase of composting in the HPC group reached 63%, which was conducive to the consumption of organic matter and temperature rise during composting. In the maturation phase of composting, due to the degradation of organic matter, the bacterial community was stimulated to evolve from the function of degrading organic matter to promoting compost maturity.
2023, 41(6): 132-142,173.
doi: 10.13205/j.hjgc.202306018
Abstract:
Bimetallic nickel-iron nanoparticles were supported on mesoporous alumina in order to improve their dispersion performance, suspension ability and mobility in groundwater, as well as aqueous dechlorination reactivity and reactive longevity toward chlorinated organic contaminants in groundwater. Mesoporous alumina with a pore diameter of 7.65 nm, a pore volume of 0.68 cm3/g, and a specific surface area of 350 m2/g was prepared. Then bimetallic Ni-Fe (FeNi3) nanoparticles were produced on mesoporous alumina by calcining in hydrogen gas (10% by volume) at 400℃. A nickel-iron layered double hydroxides was impregnated onto the carrier. Bare Ni-Fe nanoparticles were 50~100 nm in diameter and agglomerated together. In comparison, the crystallite size of the supported Ni-Fe nanoparticles decreased to 11.5 nm due to the interfacial interaction between the nanoparticles and the mesoporous alumina, and the confinement effect of the mesoporous structure. In addition, the dispersion performance of the supported Ni-Fe nanoparticles was dramatically enhanced. The composite of Ni-Fe nanoparticles and mesoporous alumina, i.e., Ni-Fe-nanoparticles/mesoporous-alumina, remained suspending in water within 12 h, whereas bare Ni-Fe nanoparticles precipitated in merely 2 min. When trichloroethylene was loaded at an initial concentration of 23.7 mg/L, i.e., 1000 times the average concentration in groundwater, the overall yield of two-carbon hydrocarbons was 12.03% in 48 h by the supported Ni-Fe nanoparticles, which was approximately 9 times greater than the bare counterpart. Furthermore, Ni-Fe-nanoparticles/mesoporous-alumina showed excellent adsorption activity, and only 0.41% of trichloroethylene remained in 48 h. The composite showed a remarkable reactive longevity in multi-run use, with the yield of two-carbon hydrocarbons during the 4th run being the same as the 1st run (0.23 μmol). Furthermore, it still exhibited adsorption and dechlorination activity until the 8th run, during which the degradation of trichloroethylene and yield of two-carbon hydrocarbons were 1.05 μmol and 0.043 μmol, respectively. The results indicate that the composite is a promising material for remediation of groundwater contaminated by chlorinated organic compounds.
Bimetallic nickel-iron nanoparticles were supported on mesoporous alumina in order to improve their dispersion performance, suspension ability and mobility in groundwater, as well as aqueous dechlorination reactivity and reactive longevity toward chlorinated organic contaminants in groundwater. Mesoporous alumina with a pore diameter of 7.65 nm, a pore volume of 0.68 cm3/g, and a specific surface area of 350 m2/g was prepared. Then bimetallic Ni-Fe (FeNi3) nanoparticles were produced on mesoporous alumina by calcining in hydrogen gas (10% by volume) at 400℃. A nickel-iron layered double hydroxides was impregnated onto the carrier. Bare Ni-Fe nanoparticles were 50~100 nm in diameter and agglomerated together. In comparison, the crystallite size of the supported Ni-Fe nanoparticles decreased to 11.5 nm due to the interfacial interaction between the nanoparticles and the mesoporous alumina, and the confinement effect of the mesoporous structure. In addition, the dispersion performance of the supported Ni-Fe nanoparticles was dramatically enhanced. The composite of Ni-Fe nanoparticles and mesoporous alumina, i.e., Ni-Fe-nanoparticles/mesoporous-alumina, remained suspending in water within 12 h, whereas bare Ni-Fe nanoparticles precipitated in merely 2 min. When trichloroethylene was loaded at an initial concentration of 23.7 mg/L, i.e., 1000 times the average concentration in groundwater, the overall yield of two-carbon hydrocarbons was 12.03% in 48 h by the supported Ni-Fe nanoparticles, which was approximately 9 times greater than the bare counterpart. Furthermore, Ni-Fe-nanoparticles/mesoporous-alumina showed excellent adsorption activity, and only 0.41% of trichloroethylene remained in 48 h. The composite showed a remarkable reactive longevity in multi-run use, with the yield of two-carbon hydrocarbons during the 4th run being the same as the 1st run (0.23 μmol). Furthermore, it still exhibited adsorption and dechlorination activity until the 8th run, during which the degradation of trichloroethylene and yield of two-carbon hydrocarbons were 1.05 μmol and 0.043 μmol, respectively. The results indicate that the composite is a promising material for remediation of groundwater contaminated by chlorinated organic compounds.
2023, 41(6): 143-150.
doi: 10.13205/j.hjgc.202306019
Abstract:
The common treatment equipment includes cyanobacteria magnetic capture vessels, pressurized cyanobacterial control vessels, submersible pressure cyanobacteria controllers and combined cyanobacteria water separation devices. The application of equipment may cause impacts on the environment. It is necessary to identify the impacts of typical treatment equipment. Based on the life cycle assessment (LCA) method, this study selected typical cyanobacterial treatment equipment as the evaluation object, analyzed its environmental impacts in the production and operation stages, and screened out the main stages and the main influencing factors leading to environmental load. The results showed that the total environmental loads of the four devices were in an order of submersible pressure cyanobacteria controller
The common treatment equipment includes cyanobacteria magnetic capture vessels, pressurized cyanobacterial control vessels, submersible pressure cyanobacteria controllers and combined cyanobacteria water separation devices. The application of equipment may cause impacts on the environment. It is necessary to identify the impacts of typical treatment equipment. Based on the life cycle assessment (LCA) method, this study selected typical cyanobacterial treatment equipment as the evaluation object, analyzed its environmental impacts in the production and operation stages, and screened out the main stages and the main influencing factors leading to environmental load. The results showed that the total environmental loads of the four devices were in an order of submersible pressure cyanobacteria controller
2023, 41(6): 151-156.
doi: 10.13205/j.hjgc.202306020
Abstract:
In this paper, foamed self-insulating blocks were prepared using fly ash sintered ceramsite as the main lightweight aggregate. The influence of the ratio of fly ash sintered ceramsite on the mechanical properties and thermal conductivity of the insulating blocks was studied, and the thermal insulation performance of the thermal insulating block was enhanced by adding a certain amount of lightweight commercial ceramsite. The results showed that the thermal conductivity of the blocks decreased with the increasing production of fly ash sintered ceramsite, with a lowest value of 0.47 W/(m·K), when the ratio of fly ash sintered ceramsite at 60%. When the ratio of fly ash sintered ceramsite and commercial ceramsite was 2:1, the thermal conductivity, compressive strength and bulk density of the blocks were 0.33 W/(m·K), 6.89 MPa and 1046.80 kg/m3, respectively, and the thermal conductivity of the block was reduced by 29.79% when compared to the block without adding commercial ceramsite, indicating good thermal insulation performance. This study provides a guideline to produce lightweight thermal insulation building materials using fly ash sintered ceramsite.
In this paper, foamed self-insulating blocks were prepared using fly ash sintered ceramsite as the main lightweight aggregate. The influence of the ratio of fly ash sintered ceramsite on the mechanical properties and thermal conductivity of the insulating blocks was studied, and the thermal insulation performance of the thermal insulating block was enhanced by adding a certain amount of lightweight commercial ceramsite. The results showed that the thermal conductivity of the blocks decreased with the increasing production of fly ash sintered ceramsite, with a lowest value of 0.47 W/(m·K), when the ratio of fly ash sintered ceramsite at 60%. When the ratio of fly ash sintered ceramsite and commercial ceramsite was 2:1, the thermal conductivity, compressive strength and bulk density of the blocks were 0.33 W/(m·K), 6.89 MPa and 1046.80 kg/m3, respectively, and the thermal conductivity of the block was reduced by 29.79% when compared to the block without adding commercial ceramsite, indicating good thermal insulation performance. This study provides a guideline to produce lightweight thermal insulation building materials using fly ash sintered ceramsite.
2023, 41(6): 157-165,221.
doi: 10.13205/j.hjgc.202306021
Abstract:
Accurate prediction of ozone and PM2.5 concentration can provide a scientific basis for the prevention and control of photochemical pollution. However, the prediction accuracy of the existing ozone and PM2.5 concentration prediction models is still not sufficient. Based on the daily average ozone and PM2.5 concentration data in Nanjing from January 1, 2015, to June 30, 2021, a pollutant concentration prediction model for complementary ensemble empirical mode decomposition (CEEMD) secondary decomposition and long and short-term memory neural network (LSTM) was constructed. Firstly, the ozone and PM2.5 concentration sequence was decomposed by variational mode decomposition (VMD). Secondly, the CEEMD secondary decomposition was used with residual components, and then all the decomposed subsequences were predicted by LSTM. Finally, the output result was reconstructed to get the final result. The results showed that for the forcast of PM2.5 and O3 concentration in Nanjing, comparing with the other models, the model VMD-CEEMD-LSTM proposed in this paper was superior and robust, with the RMSE of ozone and PM2.5 concentrations of 16.47 and 5.12, respectively. This study could provide valuable references for analyzing ozone and PM2.5 pollution trend.
Accurate prediction of ozone and PM2.5 concentration can provide a scientific basis for the prevention and control of photochemical pollution. However, the prediction accuracy of the existing ozone and PM2.5 concentration prediction models is still not sufficient. Based on the daily average ozone and PM2.5 concentration data in Nanjing from January 1, 2015, to June 30, 2021, a pollutant concentration prediction model for complementary ensemble empirical mode decomposition (CEEMD) secondary decomposition and long and short-term memory neural network (LSTM) was constructed. Firstly, the ozone and PM2.5 concentration sequence was decomposed by variational mode decomposition (VMD). Secondly, the CEEMD secondary decomposition was used with residual components, and then all the decomposed subsequences were predicted by LSTM. Finally, the output result was reconstructed to get the final result. The results showed that for the forcast of PM2.5 and O3 concentration in Nanjing, comparing with the other models, the model VMD-CEEMD-LSTM proposed in this paper was superior and robust, with the RMSE of ozone and PM2.5 concentrations of 16.47 and 5.12, respectively. This study could provide valuable references for analyzing ozone and PM2.5 pollution trend.
2023, 41(6): 166-173.
doi: 10.13205/j.hjgc.202306022
Abstract:
With the rapid development of urbanization, the impervious area increased markedly. The detention tank is one of the important measures to alleviate urban flooding. However, the application of detention tanks faces many problems, such as the unreasonable design method, and a lack of lost-benefit analysis. A novel optimization method of the detention tank based on the coupling of InfoWorks ICM and the multi-objective genetic algorithm was proposed. Taking an urban area as an example, the waterlogging area and detention volume were analyzed by InfoWorks ICM. The total overflow volume of ponding points in the area was 14355 m3, 17102 m3 and 19838 m3 under the 5-year,10-year and 20-year return periods of rainfall. Coupled the above results with the multi-objective genetic algorithm, with the reduction of project cost and waterlogging risk as the objective function, and with the floor area and efficiency index of the reservoir as the constraint condition, five optimization schemes were proposed. By comparing the distribution characteristics of the optimal solution under 5-year, 10-year,20-year rainfall return periods, scheme 2 was determined as the optimal scheme, and the corresponding construction cost of the storage tanks was 2713, 4612, 62.4 million yuan. Therefore, the method of coupling the InfoWorks ICM model with genetic algorithm can be used to optimize the scale of urban waterlogging storage ponds.
With the rapid development of urbanization, the impervious area increased markedly. The detention tank is one of the important measures to alleviate urban flooding. However, the application of detention tanks faces many problems, such as the unreasonable design method, and a lack of lost-benefit analysis. A novel optimization method of the detention tank based on the coupling of InfoWorks ICM and the multi-objective genetic algorithm was proposed. Taking an urban area as an example, the waterlogging area and detention volume were analyzed by InfoWorks ICM. The total overflow volume of ponding points in the area was 14355 m3, 17102 m3 and 19838 m3 under the 5-year,10-year and 20-year return periods of rainfall. Coupled the above results with the multi-objective genetic algorithm, with the reduction of project cost and waterlogging risk as the objective function, and with the floor area and efficiency index of the reservoir as the constraint condition, five optimization schemes were proposed. By comparing the distribution characteristics of the optimal solution under 5-year, 10-year,20-year rainfall return periods, scheme 2 was determined as the optimal scheme, and the corresponding construction cost of the storage tanks was 2713, 4612, 62.4 million yuan. Therefore, the method of coupling the InfoWorks ICM model with genetic algorithm can be used to optimize the scale of urban waterlogging storage ponds.
2023, 41(6): 174-180.
doi: 10.13205/j.hjgc.202306023
Abstract:
Aiming to reduce the energy consumption of the secondary pumping station, this study made full use of the regulation and storage function of the low-level water tank in the secondary water supply system, and built an optimal scheduling model for the water supply pipe network. The model took a step-by-step optimization strategy, and accomplished the optimal scheduling of the low-level water tank and the secondary pumping station in turn. Firstly, a quadratic programming model was established to obtain the control command of the low-level water tank inlet valve and the ideal water supply flow of the pipe network. Then, taking the ideal water supply flow and pumping energy consumption as the optimization goals, along with feedback adjustment at the same time, the optimal scheduling model of the secondary pumping station based on the NSGA2 algorithm was constructed. The model was applied to the water supply pipe network in GS District of SZ City, and the results showed that the linkage dispatch between the low-level water tank and the secondary pump station could reduce the energy consumption of water supply by about 7.7%, compared with the simple regulation of the water pump. This model provides a theoretical reference for exploring the optimal scheduling of the whole water supply network system.
Aiming to reduce the energy consumption of the secondary pumping station, this study made full use of the regulation and storage function of the low-level water tank in the secondary water supply system, and built an optimal scheduling model for the water supply pipe network. The model took a step-by-step optimization strategy, and accomplished the optimal scheduling of the low-level water tank and the secondary pumping station in turn. Firstly, a quadratic programming model was established to obtain the control command of the low-level water tank inlet valve and the ideal water supply flow of the pipe network. Then, taking the ideal water supply flow and pumping energy consumption as the optimization goals, along with feedback adjustment at the same time, the optimal scheduling model of the secondary pumping station based on the NSGA2 algorithm was constructed. The model was applied to the water supply pipe network in GS District of SZ City, and the results showed that the linkage dispatch between the low-level water tank and the secondary pump station could reduce the energy consumption of water supply by about 7.7%, compared with the simple regulation of the water pump. This model provides a theoretical reference for exploring the optimal scheduling of the whole water supply network system.
2023, 41(6): 181-186.
doi: 10.13205/j.hjgc.202306024
Abstract:
The sludge yield of 12 water purification plants in L District of Shenzhen from 2016 to 2020 was investigated. The results showed that the sludge yield ranged from 0.51 to 2.66 t DS/104 m3, and its average value showed an increasing trend. In most cases, upgrading the wastewater treatment process can reduce sludge yield. Influent SS and BOD5 were positively correlated with sludge yield. The outward sludge moisture affected the sludge yield by influencing the dosage of chemicals in sludge treatment. Silo storage condition could change the weight of sludge and thus affect the sludge yield. In order to reduce the sludge yield, optimizing the wastewater treatment system, improving the influent biodegradability, reducing the dosage of chemicals and improving the silo storage conditions should be considered. It is suggested to use specific in-situ sludge reduction measures including using bypass inlet or multi-point aeration, controlling inflow suspended solids, strengthening sediment separation in the pretreatment stage, and adopting closed silos and transportation modes.
The sludge yield of 12 water purification plants in L District of Shenzhen from 2016 to 2020 was investigated. The results showed that the sludge yield ranged from 0.51 to 2.66 t DS/104 m3, and its average value showed an increasing trend. In most cases, upgrading the wastewater treatment process can reduce sludge yield. Influent SS and BOD5 were positively correlated with sludge yield. The outward sludge moisture affected the sludge yield by influencing the dosage of chemicals in sludge treatment. Silo storage condition could change the weight of sludge and thus affect the sludge yield. In order to reduce the sludge yield, optimizing the wastewater treatment system, improving the influent biodegradability, reducing the dosage of chemicals and improving the silo storage conditions should be considered. It is suggested to use specific in-situ sludge reduction measures including using bypass inlet or multi-point aeration, controlling inflow suspended solids, strengthening sediment separation in the pretreatment stage, and adopting closed silos and transportation modes.
2023, 41(6): 187-193,209.
doi: 10.13205/j.hjgc.202306025
Abstract:
Taking the typical small and medium-sized rivers of the plain river network area in Jiashan County of Zhejiang Province as the study area, the water quality index (WQI) method was used for water quality assessment, according to monthly monitoring data of fourteen sections from 2015 to 2020. On this basis, the spatio-temporal variation characteristics of the water quality were explored using the Mann-Kendall (M-K) trend test combined with geographic information system (GIS). The results indicated that the average WQI value was 65.09 in the five years, showing the evaluation level of "medium". The water quality of rivers had obvious spatio-temporal differences i. e., water quality was improved gradually from 2015 to 2020, superior in non-flood season to flood season within intra-annual variation and better in the northern area compared to southern. The main influencing factors of spatio-temporal differences in water quality were precipitation, human activity and land use types. These results would provide critical information for the management of water resources.
Taking the typical small and medium-sized rivers of the plain river network area in Jiashan County of Zhejiang Province as the study area, the water quality index (WQI) method was used for water quality assessment, according to monthly monitoring data of fourteen sections from 2015 to 2020. On this basis, the spatio-temporal variation characteristics of the water quality were explored using the Mann-Kendall (M-K) trend test combined with geographic information system (GIS). The results indicated that the average WQI value was 65.09 in the five years, showing the evaluation level of "medium". The water quality of rivers had obvious spatio-temporal differences i. e., water quality was improved gradually from 2015 to 2020, superior in non-flood season to flood season within intra-annual variation and better in the northern area compared to southern. The main influencing factors of spatio-temporal differences in water quality were precipitation, human activity and land use types. These results would provide critical information for the management of water resources.
2023, 41(6): 194-201,258.
doi: 10.13205/j.hjgc.202306026
Abstract:
The layout of construction waste recycling facilities is the key to the construction of waste recycling network. In order to realize the multi-cycle consideration of facility location layout, a time-sharing evolution planning method was proposed, which integrated the facility processing capacity, social negative effect and construction waste production characteristics in different periods, and established a multi-objective programming model to minimize the regional economic cost and environmental negative impact. The genetic algorithm was used to solve the problem intelligently, and the dynamic optimization scheme of the facility location layout was obtained. Taking the main urban area of Xining as an example, a three-period construction waste recycling facility network was established to verify the effectiveness of the model. The results showed that the candidate points at B2 and B3 in stage t1 (2020), and B2, B3 and B5 in stage t2 (2025) and t3 (2030) were the optimal location, and the fitness values converged to 3.7925×108, 4.392×108 and 5.0205×108, respectively. This model can effectively balance the contradiction between economy and environment in facility location layout, and realize the dynamic optimization of facility location. The research provides certain reference for government and other relevant decision-makers to construct regional construction waste recycling facility networks.
The layout of construction waste recycling facilities is the key to the construction of waste recycling network. In order to realize the multi-cycle consideration of facility location layout, a time-sharing evolution planning method was proposed, which integrated the facility processing capacity, social negative effect and construction waste production characteristics in different periods, and established a multi-objective programming model to minimize the regional economic cost and environmental negative impact. The genetic algorithm was used to solve the problem intelligently, and the dynamic optimization scheme of the facility location layout was obtained. Taking the main urban area of Xining as an example, a three-period construction waste recycling facility network was established to verify the effectiveness of the model. The results showed that the candidate points at B2 and B3 in stage t1 (2020), and B2, B3 and B5 in stage t2 (2025) and t3 (2030) were the optimal location, and the fitness values converged to 3.7925×108, 4.392×108 and 5.0205×108, respectively. This model can effectively balance the contradiction between economy and environment in facility location layout, and realize the dynamic optimization of facility location. The research provides certain reference for government and other relevant decision-makers to construct regional construction waste recycling facility networks.
2023, 41(6): 202-209.
doi: 10.13205/j.hjgc.202306027
Abstract:
In order to reveal the changing law of water resources carrying capacity (WRCC) in Kunming and provide decision support for regional water resources allocation and sustainable utilization, this paper constructed a comprehensive evaluation model of WRCC based on the entropy weight method and Markov transfer model, and analyzed the results of the spatiotemporal transfer and evolution characteristics of WRCC in the study area over the past 25 years. The results showed that the overall water resource carrying capacity of the research area is relatively low, with significant spatial differences. Among them, the northern and northeastern regions are areas with low water resource carrying capacity due to resource scarcity, with an average annual water resource carrying capacity of 0.26 to 0.38 during the research period; the central and southwest regions have developed economies and the largest population density, and are low in water resources carrying capacity due to water shortage. The multi-year average value of water resources carrying capacity in the study period is 0.30 to 0.41; the southeast region is relatively rich in precipitation, low in population density, and relatively higher in water resources carrying capacity. The multi-year average value of water resources carrying capacity in the study period is 0.37 to 0.54. In addition, the overall spatial transfer and change frequency of water resource carrying capacity in the research area is relatively high. Among them, the frequency of changes in the central region reached a maximum of four times during the five research periods, indicating that the level of water resource carrying capacity in the study area has a significant periodic change, which is closely related to the extremely uneven spatiotemporal distribution of precipitation, imbalanced supply and demand of water resources, seasonal water scarcity, and population distribution in the study area.
In order to reveal the changing law of water resources carrying capacity (WRCC) in Kunming and provide decision support for regional water resources allocation and sustainable utilization, this paper constructed a comprehensive evaluation model of WRCC based on the entropy weight method and Markov transfer model, and analyzed the results of the spatiotemporal transfer and evolution characteristics of WRCC in the study area over the past 25 years. The results showed that the overall water resource carrying capacity of the research area is relatively low, with significant spatial differences. Among them, the northern and northeastern regions are areas with low water resource carrying capacity due to resource scarcity, with an average annual water resource carrying capacity of 0.26 to 0.38 during the research period; the central and southwest regions have developed economies and the largest population density, and are low in water resources carrying capacity due to water shortage. The multi-year average value of water resources carrying capacity in the study period is 0.30 to 0.41; the southeast region is relatively rich in precipitation, low in population density, and relatively higher in water resources carrying capacity. The multi-year average value of water resources carrying capacity in the study period is 0.37 to 0.54. In addition, the overall spatial transfer and change frequency of water resource carrying capacity in the research area is relatively high. Among them, the frequency of changes in the central region reached a maximum of four times during the five research periods, indicating that the level of water resource carrying capacity in the study area has a significant periodic change, which is closely related to the extremely uneven spatiotemporal distribution of precipitation, imbalanced supply and demand of water resources, seasonal water scarcity, and population distribution in the study area.
2023, 41(6): 210-221.
doi: 10.13205/j.hjgc.202306028
Abstract:
Microbial growth significantly affects water safety in drinking water distribution systems, where microorganisms are mainly found in biofilms. In recent years, with the development of high-throughput genetic sequencing, more and more attention has been paid to multi-species biofilms. Factors such as microbial interspecific interactions can affect the formation of multi-species biofilms, and controlling the growth of microorganisms in the biofilms of the drinking water distribution systems is essential to limit water-borne diseases. In this paper, the preliminary mechanisms of multi-species biofilms formation are discussed from the aspects of extracellular polymeric substances, biofilm-regulated genes, antibiotics and environmental adaptability, and then the interspecific interactions (competition, synergism and neutralism) among microorganisms in multi-species biofilms in drinking water distribution systems are reviewed. The mechanisms of interspecific interactions and their effects on biofilm formation are discussed from the aspects of quorum sensing signal molecules, metabolic commensalism and cross-feeding. Finally, the influencing factors of microbial interspecific interactions are summarized from the biological and non-biological perspectives. Based on the above analysis, this paper proposes to study the mechanisms of microbial interspecific interactions and the factors of multi-species biofilms formation, which provides a new idea for limiting biofilm growth and ensuring the safety of drinking water quality.
Microbial growth significantly affects water safety in drinking water distribution systems, where microorganisms are mainly found in biofilms. In recent years, with the development of high-throughput genetic sequencing, more and more attention has been paid to multi-species biofilms. Factors such as microbial interspecific interactions can affect the formation of multi-species biofilms, and controlling the growth of microorganisms in the biofilms of the drinking water distribution systems is essential to limit water-borne diseases. In this paper, the preliminary mechanisms of multi-species biofilms formation are discussed from the aspects of extracellular polymeric substances, biofilm-regulated genes, antibiotics and environmental adaptability, and then the interspecific interactions (competition, synergism and neutralism) among microorganisms in multi-species biofilms in drinking water distribution systems are reviewed. The mechanisms of interspecific interactions and their effects on biofilm formation are discussed from the aspects of quorum sensing signal molecules, metabolic commensalism and cross-feeding. Finally, the influencing factors of microbial interspecific interactions are summarized from the biological and non-biological perspectives. Based on the above analysis, this paper proposes to study the mechanisms of microbial interspecific interactions and the factors of multi-species biofilms formation, which provides a new idea for limiting biofilm growth and ensuring the safety of drinking water quality.
2023, 41(6): 222-232.
doi: 10.13205/j.hjgc.202306029
Abstract:
Anaerobic digestion is one of the most effective strategies for resource utilization and harmless disposal of food waste. However, the high levels of heterologous substances in food waste might exhibit negative impacts on these systems. This work mainly investigated the influences of typical heterologous substances (i.e., NaCl, condiment, etc.) on the anaerobic digestion of food waste. The results indicated that these heterologous substances inhibit the digestion efficiency by regulating the microbial community structures (i.e., Methanosaeta, Methanobacterium kluyver and van niel), metabolic activities (i.e., cell membrane permeability, osmotic pressure, and activities of key enzymes), microbial metabolic functions, and expressions of functional genes (i.e., ACAS and mcrA). The appropriate pretreatment methods, such as physical pretreatments (i.e., thermal, ultrasonic, biochar adsorption, etc.), chemical pretreatments (i.e., acid, alkali, advanced oxidation process, etc.) and biological pretreatments (i.e., domestication and enrichment of functional bacteria, etc.), were effective to ameliorate such inhibitory effects. Besides, the future prospects were given from the perspectives of the combined effects of various heterologous substances on the digestion systems, as well as the necessity of source classification and reaction process optimization for enhanced digestion performance. This work would provide theoretical guidance for improving the anaerobic digestion of food waste.
Anaerobic digestion is one of the most effective strategies for resource utilization and harmless disposal of food waste. However, the high levels of heterologous substances in food waste might exhibit negative impacts on these systems. This work mainly investigated the influences of typical heterologous substances (i.e., NaCl, condiment, etc.) on the anaerobic digestion of food waste. The results indicated that these heterologous substances inhibit the digestion efficiency by regulating the microbial community structures (i.e., Methanosaeta, Methanobacterium kluyver and van niel), metabolic activities (i.e., cell membrane permeability, osmotic pressure, and activities of key enzymes), microbial metabolic functions, and expressions of functional genes (i.e., ACAS and mcrA). The appropriate pretreatment methods, such as physical pretreatments (i.e., thermal, ultrasonic, biochar adsorption, etc.), chemical pretreatments (i.e., acid, alkali, advanced oxidation process, etc.) and biological pretreatments (i.e., domestication and enrichment of functional bacteria, etc.), were effective to ameliorate such inhibitory effects. Besides, the future prospects were given from the perspectives of the combined effects of various heterologous substances on the digestion systems, as well as the necessity of source classification and reaction process optimization for enhanced digestion performance. This work would provide theoretical guidance for improving the anaerobic digestion of food waste.
2023, 41(6): 233-238.
doi: 10.13205/j.hjgc.202306030
Abstract:
As a set of complex discrete systems, we need to establish and simulate mathematical models with different complexity to predict and study the properties of environmental systems. These computational experiments typically require a combination of discrete and continuous variables and process operating at different time scales. As a visual modelling tool, Petri net can accurately describe the environmental events. This paper reviews the research on Petri net modelling in the field of ecological environment by domestic and foreign scholars in recent years. Focusing on five seminal research findings, including the application of Petri net modelling in the field of environmental impact assessment, in the simulation of pollutant emission limits, in environmental data processing, in risk assessment, and in environmental decision-making, the future research directions of Petri modelling in the informative representation of environmental problems, transformation and processing of data, integration with neural networks and algorithms, and establishment of expert systems are discussed.
As a set of complex discrete systems, we need to establish and simulate mathematical models with different complexity to predict and study the properties of environmental systems. These computational experiments typically require a combination of discrete and continuous variables and process operating at different time scales. As a visual modelling tool, Petri net can accurately describe the environmental events. This paper reviews the research on Petri net modelling in the field of ecological environment by domestic and foreign scholars in recent years. Focusing on five seminal research findings, including the application of Petri net modelling in the field of environmental impact assessment, in the simulation of pollutant emission limits, in environmental data processing, in risk assessment, and in environmental decision-making, the future research directions of Petri modelling in the informative representation of environmental problems, transformation and processing of data, integration with neural networks and algorithms, and establishment of expert systems are discussed.
2023, 41(6): 239-247.
doi: 10.13205/j.hjgc.202306031
Abstract:
High salinity wastewater is difficult to treat. The membrane method is widely paid attention to due to its low cost, small footprint, and convenient process operation. Metal-organic framework nanomaterials (MOFs) have tunable nanochannels, high specific surface area, and good compatibility with polymers, so MOFs membrane has a good potential in treating high-salinity wastewater. In this review, the advantages and separation principles of MOFs mixed matrix membranes and thin-film nanocomposite membranes are briefly described. Then, based on the synthesis and design ideas of MOFs membranes, the basic preparation strategies of MOFs membrane materials are analyzed. Finally, the research progress of MOFs membrane materials in treating high-salinity industrial wastewater and seawater desalination is illustrated. The bottleneck problems encountered by MOFs membrane materials in the treatment of high-salt water are also summarized, and the development directions of MOFs membranes for high-salinity wastewater treatment are prospected. The analysis shows that the in-depth exploration of membrane fouling and scaling mechanism and prevention strategy, the disperse problem of MOFs in membranes, the control of membrane cost, and scale-up production need to be carried out urgently. With the increasingly stringent emission standards, the development of stable, economic, and eco-friendly MOFs membranes is the development direction for high-salt wastewater treatment.
High salinity wastewater is difficult to treat. The membrane method is widely paid attention to due to its low cost, small footprint, and convenient process operation. Metal-organic framework nanomaterials (MOFs) have tunable nanochannels, high specific surface area, and good compatibility with polymers, so MOFs membrane has a good potential in treating high-salinity wastewater. In this review, the advantages and separation principles of MOFs mixed matrix membranes and thin-film nanocomposite membranes are briefly described. Then, based on the synthesis and design ideas of MOFs membranes, the basic preparation strategies of MOFs membrane materials are analyzed. Finally, the research progress of MOFs membrane materials in treating high-salinity industrial wastewater and seawater desalination is illustrated. The bottleneck problems encountered by MOFs membrane materials in the treatment of high-salt water are also summarized, and the development directions of MOFs membranes for high-salinity wastewater treatment are prospected. The analysis shows that the in-depth exploration of membrane fouling and scaling mechanism and prevention strategy, the disperse problem of MOFs in membranes, the control of membrane cost, and scale-up production need to be carried out urgently. With the increasingly stringent emission standards, the development of stable, economic, and eco-friendly MOFs membranes is the development direction for high-salt wastewater treatment.
2023, 41(6): 248-258.
doi: 10.13205/j.hjgc.202306032
Abstract:
Due to the low grade of domestic iron ore, sintered ore has become an essential raw material in steel production. However, iron ore powder sintering emits a large amount of flue gas containing dust, S, N oxides and other pollutants, which is an important reason for environmental problems such as acid rain, ozone layer leaks, and PM2.5. These pollutants also pose a serious threat to human health, so proper management is urgently needed. This article introduced the generation mechanisms and current pollution status of several pollutants in sintering flue gas, and summarized the treatment methods and emerging treatment technologies for pollutants. It was found that individual pollutant treatment method could no longer meet the requirements of ultra-low emission of steel enterprises, and collaborative treatment methods also had their own shortcomings. Therefore, enterprises need to consider the characteristics of pollutants, production indicators, emission requirements, and other factors, and choose one or more suitable collaborative treatment processes for flue gas treatment. On this basis, a comprehensive treatment method using new fuel processes, such as coke powder and biomass fuel to reduce flue gas pollutants from the source, and combining it with cooperative treatment methods for pollutants at the end of the process was proposed, in order to realize the whole cycle treatment process of sintering pollutants. This paper could provide a reference for the prevention and control of pollutants in iron and steel industry in China and help the high-quality and green development of iron and steel enterprises.
Due to the low grade of domestic iron ore, sintered ore has become an essential raw material in steel production. However, iron ore powder sintering emits a large amount of flue gas containing dust, S, N oxides and other pollutants, which is an important reason for environmental problems such as acid rain, ozone layer leaks, and PM2.5. These pollutants also pose a serious threat to human health, so proper management is urgently needed. This article introduced the generation mechanisms and current pollution status of several pollutants in sintering flue gas, and summarized the treatment methods and emerging treatment technologies for pollutants. It was found that individual pollutant treatment method could no longer meet the requirements of ultra-low emission of steel enterprises, and collaborative treatment methods also had their own shortcomings. Therefore, enterprises need to consider the characteristics of pollutants, production indicators, emission requirements, and other factors, and choose one or more suitable collaborative treatment processes for flue gas treatment. On this basis, a comprehensive treatment method using new fuel processes, such as coke powder and biomass fuel to reduce flue gas pollutants from the source, and combining it with cooperative treatment methods for pollutants at the end of the process was proposed, in order to realize the whole cycle treatment process of sintering pollutants. This paper could provide a reference for the prevention and control of pollutants in iron and steel industry in China and help the high-quality and green development of iron and steel enterprises.
