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2024, Volume 42, Issue 12
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2024,
42(12):
1-7.
doi: 10.13205/j.hjgc.202412001
Abstract:
Water quality prediction is an important part of water pollution prevention and control. To improve the accuracy of water quality prediction and the early warning mechanism of the Sanmenxia Reservoir on the mainstream of the Yellow River, five reservoir water quality monitoring indicators including pH, dissolved oxygen, ammonia nitrogen, total phosphorus and permanganate index, were selected for accurate prediction of water quality. The VMD-SSA-LSTM model and VMD-SSA-SVR model were constructed. The variational mode decomposition (VMD) was used to denoise the river water quality data. The sparrow search algorithm (SSA) was selected to optimize the model parameters of long short-term memory artificial neural network (LSTM) and support vector regression (SVR), and the prediction effects of the two models were compared by mean absolute error (MAE), mean bias error (MBE), mean square error (MSE) and root mean square error (RMSE). The results showed that the four error index values of the prediction results of the VMD-SSA-SVR model were smaller than that of the VMD-SSA-LSTM model, indicating that the VMD-SSA-SVR model had a more accurate prediction effect on river water quality changes. This study enriches the research on the river water quality prediction model in the Sanmenxia section of the Yellow River Basin, and provides technical reference for ecological protection and high-quality development of the Yellow River Basin.
Water quality prediction is an important part of water pollution prevention and control. To improve the accuracy of water quality prediction and the early warning mechanism of the Sanmenxia Reservoir on the mainstream of the Yellow River, five reservoir water quality monitoring indicators including pH, dissolved oxygen, ammonia nitrogen, total phosphorus and permanganate index, were selected for accurate prediction of water quality. The VMD-SSA-LSTM model and VMD-SSA-SVR model were constructed. The variational mode decomposition (VMD) was used to denoise the river water quality data. The sparrow search algorithm (SSA) was selected to optimize the model parameters of long short-term memory artificial neural network (LSTM) and support vector regression (SVR), and the prediction effects of the two models were compared by mean absolute error (MAE), mean bias error (MBE), mean square error (MSE) and root mean square error (RMSE). The results showed that the four error index values of the prediction results of the VMD-SSA-SVR model were smaller than that of the VMD-SSA-LSTM model, indicating that the VMD-SSA-SVR model had a more accurate prediction effect on river water quality changes. This study enriches the research on the river water quality prediction model in the Sanmenxia section of the Yellow River Basin, and provides technical reference for ecological protection and high-quality development of the Yellow River Basin.
2024,
42(12):
8-17.
doi: 10.13205/j.hjgc.202412002
Abstract:
Reservoir is an important source of methane (CH4) emissions. The community structure of methanogens in reservoir sediments and its influencing factors are of great significance for understanding the mechanism of CH4 emissions. Surface sediment samples from 10 cascade reservoirs in the upper Yellow River were collected in May (dry season) and August (wet season) in 2023. 16S rRNA high-throughput sequencing technology, statistical analysis and null model were used to investigate the community characteristics, diversity and community assembly processes of methanogens in sediments of the cascade reservoirs in the upper Yellow River in different seasons. The results showed that: 1) in the dry season, Methanobacterium is the dominant genus, while in the wet season, Methanosarcina takes over as the dominant genus; 2) the reservoir age had a significant effect on α diversity of the methanogenic bacteria community (P<0.05), while the season had a significant effect on β diversity of methanogenic bacteria community (P<0.05); 3) the main environmental factors affecting the composition of methanogenic communities were pH, total nitrogen and temperature. The stochastic process dominated methanogenic community assembly processes, in which drift was the strongest (54.25%). The research findings provide scientific insights for understanding the mechanisms of CH4 emissions from reservoirs and their regulation.
Reservoir is an important source of methane (CH4) emissions. The community structure of methanogens in reservoir sediments and its influencing factors are of great significance for understanding the mechanism of CH4 emissions. Surface sediment samples from 10 cascade reservoirs in the upper Yellow River were collected in May (dry season) and August (wet season) in 2023. 16S rRNA high-throughput sequencing technology, statistical analysis and null model were used to investigate the community characteristics, diversity and community assembly processes of methanogens in sediments of the cascade reservoirs in the upper Yellow River in different seasons. The results showed that: 1) in the dry season, Methanobacterium is the dominant genus, while in the wet season, Methanosarcina takes over as the dominant genus; 2) the reservoir age had a significant effect on α diversity of the methanogenic bacteria community (P<0.05), while the season had a significant effect on β diversity of methanogenic bacteria community (P<0.05); 3) the main environmental factors affecting the composition of methanogenic communities were pH, total nitrogen and temperature. The stochastic process dominated methanogenic community assembly processes, in which drift was the strongest (54.25%). The research findings provide scientific insights for understanding the mechanisms of CH4 emissions from reservoirs and their regulation.
2024,
42(12):
18-26.
doi: 10.13205/j.hjgc.202412003
Abstract:
Continuous rainstorm events will increase the risk level of the river water ecological environment and impact its safety. In order to explore the impact of continuous rainstorm on river water quality differentiation characteristics, continuous monitoring of the water environment in the main stream and tributaries of the Yellow River from Xiaolangdi to Gaocun was carried out in the autumn flood season of 2021 (September to October). The spatiotemporal variation characteristics of pollutants in the main stream and tributaries of the Yellow River in Henan were studied and the sources of pollutants were analyzed, by routine water quality indicators and antibiotic analysis on 80 water samples during the autumn flood season. The results showed that as the flood progressed, the concentration of conventional water quality indicators in the main and tributaries of the Yellow River in Henan during the autumn flood season showed a trend of first increasing and then decreasing. Among them, NH3-N and DO changed more severely, with a changing rate of 176.1% and 37.5%, respectively; the concentration of antibiotics decreased with the weakening of the rainstorm, and the total concentration decreased from 8.32 to 41.30 ng/L, to 1.50 to 10.70 ng/L, with an average changing rate of 77.7%. The assessment results showed that the antibiotic comprehensive ecological risk during rainstorm ranged from 0.07 to 7.80, identified as a medium low risk level compared with other rivers. Among the conventional water quality indicators, agricultural non-point source pollution had the highest absolute contribution rate to total phosphorus, 61.81%; the absolute contribution rate of meteorological factors to NH3-N was the highest, 62.13%; the other indicators were mainly affected by the comprehensive impact of agricultural non-point source pollution and endogenous pollution of river water. Antibiotics mainly come from agricultural non-point source pollution in the Yellow River beach area and upstream urban sewage discharge, with an average contribution rate of 50.40% and 28.07%, respectively. It is suggested to establish a source-process-end integrated treatment system in areas with strong human activities, to weaken the adverse impact of the rainstorm runoff period on the aquatic ecological environment.
Continuous rainstorm events will increase the risk level of the river water ecological environment and impact its safety. In order to explore the impact of continuous rainstorm on river water quality differentiation characteristics, continuous monitoring of the water environment in the main stream and tributaries of the Yellow River from Xiaolangdi to Gaocun was carried out in the autumn flood season of 2021 (September to October). The spatiotemporal variation characteristics of pollutants in the main stream and tributaries of the Yellow River in Henan were studied and the sources of pollutants were analyzed, by routine water quality indicators and antibiotic analysis on 80 water samples during the autumn flood season. The results showed that as the flood progressed, the concentration of conventional water quality indicators in the main and tributaries of the Yellow River in Henan during the autumn flood season showed a trend of first increasing and then decreasing. Among them, NH3-N and DO changed more severely, with a changing rate of 176.1% and 37.5%, respectively; the concentration of antibiotics decreased with the weakening of the rainstorm, and the total concentration decreased from 8.32 to 41.30 ng/L, to 1.50 to 10.70 ng/L, with an average changing rate of 77.7%. The assessment results showed that the antibiotic comprehensive ecological risk during rainstorm ranged from 0.07 to 7.80, identified as a medium low risk level compared with other rivers. Among the conventional water quality indicators, agricultural non-point source pollution had the highest absolute contribution rate to total phosphorus, 61.81%; the absolute contribution rate of meteorological factors to NH3-N was the highest, 62.13%; the other indicators were mainly affected by the comprehensive impact of agricultural non-point source pollution and endogenous pollution of river water. Antibiotics mainly come from agricultural non-point source pollution in the Yellow River beach area and upstream urban sewage discharge, with an average contribution rate of 50.40% and 28.07%, respectively. It is suggested to establish a source-process-end integrated treatment system in areas with strong human activities, to weaken the adverse impact of the rainstorm runoff period on the aquatic ecological environment.
2024,
42(12):
27-33.
doi: 10.13205/j.hjgc.202412004
Abstract:
Protection of the Yellow River Basin is a great plan related to the great rejuvenation of China. Water is one of the key issues in the development of the Yellow River Basin. At present, soil erosion in the Loess Plateau is serious, which threatens the ecological security of the Yellow River Basin and restricts the sustainable development of local economy and society. During the 14th Five-Year Plan period, China’s ecological civilization construction entered a critical period, with carbon emission reduction as the key strategic direction, promoting the synergy of pollutants and carbon emission reduction, and facilitating the comprehensive green transformation of economic and social development, aiming to achieve a qualitative change in improving ecological environment quality. Through literature review and other methods, this study discussed the treatment path and main technical methods of urban water pollution in the Yellow River Basin from the dimensions of digitization, intelligence, and green and low-carbon. It also proposed countermeasures and suggestions such as digitally empowering the ecological civilization construction in the Yellow River Basin, building a water-energy-carbon-ecosystem synergy strategic system in the Yellow River Basin, and innovating the collaborative policy system for pollution reduction and carbon reduction in the Yellow River Basin.
Protection of the Yellow River Basin is a great plan related to the great rejuvenation of China. Water is one of the key issues in the development of the Yellow River Basin. At present, soil erosion in the Loess Plateau is serious, which threatens the ecological security of the Yellow River Basin and restricts the sustainable development of local economy and society. During the 14th Five-Year Plan period, China’s ecological civilization construction entered a critical period, with carbon emission reduction as the key strategic direction, promoting the synergy of pollutants and carbon emission reduction, and facilitating the comprehensive green transformation of economic and social development, aiming to achieve a qualitative change in improving ecological environment quality. Through literature review and other methods, this study discussed the treatment path and main technical methods of urban water pollution in the Yellow River Basin from the dimensions of digitization, intelligence, and green and low-carbon. It also proposed countermeasures and suggestions such as digitally empowering the ecological civilization construction in the Yellow River Basin, building a water-energy-carbon-ecosystem synergy strategic system in the Yellow River Basin, and innovating the collaborative policy system for pollution reduction and carbon reduction in the Yellow River Basin.
2024,
42(12):
34-42.
doi: 10.13205/j.hjgc.202412005
Abstract:
The study applied the SBM model to conduct a comprehensive performance evaluation of the synergy between pollution reduction and carbon emission reduction for the operation of 72 wastewater treatment plants in the upper and middle reaches of the Yellow River Basin in 2022. The performance evaluation indicators include pollutant removal metrics, economic input metrics, and carbon emission-related metrics. The Kruskal-Wallis method was used to examine the factors that may affect the overall operational performance of the wastewater treatment plants. The results showed that 18 wastewater treatment plants performed well in terms of overall operational efficiency, while the remaining 54 plants exhibited relatively lower performance. Low values of pure technical efficiency were identified as the main cause of the insufficient performance in some plants. Plants with a comprehensive performance score equal to 1 still had room for improvement in carbon emission reduction, while those with a score below 1 displayed varying degrees of redundancy in input-output indicators. The key factors affecting overall operational performance include pollutant load, discharge standards, wastewater treatment processes, and sludge treatment and disposal methods.
The study applied the SBM model to conduct a comprehensive performance evaluation of the synergy between pollution reduction and carbon emission reduction for the operation of 72 wastewater treatment plants in the upper and middle reaches of the Yellow River Basin in 2022. The performance evaluation indicators include pollutant removal metrics, economic input metrics, and carbon emission-related metrics. The Kruskal-Wallis method was used to examine the factors that may affect the overall operational performance of the wastewater treatment plants. The results showed that 18 wastewater treatment plants performed well in terms of overall operational efficiency, while the remaining 54 plants exhibited relatively lower performance. Low values of pure technical efficiency were identified as the main cause of the insufficient performance in some plants. Plants with a comprehensive performance score equal to 1 still had room for improvement in carbon emission reduction, while those with a score below 1 displayed varying degrees of redundancy in input-output indicators. The key factors affecting overall operational performance include pollutant load, discharge standards, wastewater treatment processes, and sludge treatment and disposal methods.
2024,
42(12):
43-51.
doi: 10.13205/j.hjgc.202412006
Abstract:
It is of decisive significance to clarify the characteristic trend of grassland desertification area change and the driving effect of each influencing factor for consolidating and promoting the desertification control effect in Ruoergai County. Through the linear fitting analysis of the correlation between desertification area change and driving factors, the key driving factors were identified, and the quantitative model of desertification area change and key driving factors was established. The results showed that the key driving factors of grassland desertification are the per capita overloading rate and the desertification control area, and the change of desertification area is significantly linearly correlated with the key driving factors. Ferevery 1% increase of the average overloading rate, the desertification area increases by 2283 mu. For every 10,000 mu of desertification control area increased, the desertification area decreased by 4562 mu. Within 5 years of the desertification monitoring period, 45.62% of the desertification grassland treated was transformed into undesertification grassland, which further confirmed that the ecological restoration of desertification grassland is a long and slow process, and the effectiveness of desertification control is lagging. Under the driving effect of desertification management projects, the transformation order of desertification land is mobile sandy land, artificial semi-fixed sandy land, artificial fixed sandy land and then undesertification land. Driven by overgrazing, the exposed sandy land and undesertification land will transform into natural fixed sandy land and exposed sandy land, respectively. The implementation of grassland overload control and desertification control policies can continuously reduce the area and degree of grassland desertification, which is the key to consolidating and promoting the effectiveness of desertification control. The study revealed the quantitative relationship between the change of grassland desertification area, human activities and policy factors, and provided an important reference for the quantitative assessment and prediction of grassland desertification change trend and accurate prevention and control.
It is of decisive significance to clarify the characteristic trend of grassland desertification area change and the driving effect of each influencing factor for consolidating and promoting the desertification control effect in Ruoergai County. Through the linear fitting analysis of the correlation between desertification area change and driving factors, the key driving factors were identified, and the quantitative model of desertification area change and key driving factors was established. The results showed that the key driving factors of grassland desertification are the per capita overloading rate and the desertification control area, and the change of desertification area is significantly linearly correlated with the key driving factors. Ferevery 1% increase of the average overloading rate, the desertification area increases by 2283 mu. For every 10,000 mu of desertification control area increased, the desertification area decreased by 4562 mu. Within 5 years of the desertification monitoring period, 45.62% of the desertification grassland treated was transformed into undesertification grassland, which further confirmed that the ecological restoration of desertification grassland is a long and slow process, and the effectiveness of desertification control is lagging. Under the driving effect of desertification management projects, the transformation order of desertification land is mobile sandy land, artificial semi-fixed sandy land, artificial fixed sandy land and then undesertification land. Driven by overgrazing, the exposed sandy land and undesertification land will transform into natural fixed sandy land and exposed sandy land, respectively. The implementation of grassland overload control and desertification control policies can continuously reduce the area and degree of grassland desertification, which is the key to consolidating and promoting the effectiveness of desertification control. The study revealed the quantitative relationship between the change of grassland desertification area, human activities and policy factors, and provided an important reference for the quantitative assessment and prediction of grassland desertification change trend and accurate prevention and control.
2024,
42(12):
52-59.
doi: 10.13205/j.hjgc.202412007
Abstract:
This study addresses the practical need for wastewater treatment in a city of Gansu Province, aiming to scientifically evaluate and identify the efficient, low-carbon wastewater treatment technologies. It innovatively integrated lifecycle assessment (LCA) with the analytic hierarchy process (AHP) to establish a comprehensive technical evaluation model for wastewater treatment. Initially, LCA was employed to systematically quantify the environmental footprint of six practically applied wastewater treatment processes (AAO, AAO+MBR, AAO+SBR, MSBR, CAST+BAF, and SBR) over their operational cycles, with a focus on their impacts on key environmental dimensions such as global warming potential, eutrophication risks in freshwater and marine ecosystems, and fossil resource consumption. Subsequently, based on the salient environmental impact findings from LCA, the AHP framework was applied to assign weights and rank the processes comprehensively, incorporating economic benefits and technical performance. LCA characterization analysis revealed that MSBR and AAO+MBR process excelled in mitigating environmental impact indicators. Normalization results further indicated that all evaluated processes significantly contribute to global climate warming, accompanied by ecological eutrophication and potential human health risks. The AHP comprehensive evaluation model explicitly demonstrated that AAO+MBR and MSBR processes held the highest weight values of 0.2255 and 0.2229, respectively, indicating their superior low-carbon benefits and technical efficiency under a comprehensive assessment framework. Additionally, the AHP indicator-level analysis emphasized the priority of performance indicators (e.g., EQI, COD removal rate) and the control of potential impacts on human health and water eutrophication during technology selection. This study not only provides a tailored solution for wastewater treatment technology selection in the targeted city of Gansu Province, but also offers scientific decision-making support for the optimization and upgrade of wastewater treatment technologies in the upstream Yellow River Basin and other similar aquatic environments. The application of this evaluation framework contributes to advancing the wastewater treatment industry in a more environmentally friendly and efficient direction, achieving a win-win scenario between economic and environmental benefits.
This study addresses the practical need for wastewater treatment in a city of Gansu Province, aiming to scientifically evaluate and identify the efficient, low-carbon wastewater treatment technologies. It innovatively integrated lifecycle assessment (LCA) with the analytic hierarchy process (AHP) to establish a comprehensive technical evaluation model for wastewater treatment. Initially, LCA was employed to systematically quantify the environmental footprint of six practically applied wastewater treatment processes (AAO, AAO+MBR, AAO+SBR, MSBR, CAST+BAF, and SBR) over their operational cycles, with a focus on their impacts on key environmental dimensions such as global warming potential, eutrophication risks in freshwater and marine ecosystems, and fossil resource consumption. Subsequently, based on the salient environmental impact findings from LCA, the AHP framework was applied to assign weights and rank the processes comprehensively, incorporating economic benefits and technical performance. LCA characterization analysis revealed that MSBR and AAO+MBR process excelled in mitigating environmental impact indicators. Normalization results further indicated that all evaluated processes significantly contribute to global climate warming, accompanied by ecological eutrophication and potential human health risks. The AHP comprehensive evaluation model explicitly demonstrated that AAO+MBR and MSBR processes held the highest weight values of 0.2255 and 0.2229, respectively, indicating their superior low-carbon benefits and technical efficiency under a comprehensive assessment framework. Additionally, the AHP indicator-level analysis emphasized the priority of performance indicators (e.g., EQI, COD removal rate) and the control of potential impacts on human health and water eutrophication during technology selection. This study not only provides a tailored solution for wastewater treatment technology selection in the targeted city of Gansu Province, but also offers scientific decision-making support for the optimization and upgrade of wastewater treatment technologies in the upstream Yellow River Basin and other similar aquatic environments. The application of this evaluation framework contributes to advancing the wastewater treatment industry in a more environmentally friendly and efficient direction, achieving a win-win scenario between economic and environmental benefits.
2024,
42(12):
60-65.
doi: 10.13205/j.hjgc.202412008
Abstract:
To investigate the ecological management effect of polyploid Arundo Donax L. in the hilly area of western Henan, polyploid Arundo Donax L., natural herbaceous plant and arborvitae-herbaceous plants runoff plots were set up in Miaoyuan Village, Yima City, Sanmenxia, and the intercepting and controlling effect of polyploid Arundo Donax L. on surface runoff, sediment, nitrogen and phosphorus was analyzed through three rainfall comparison. The results showed that: 1) the intercepting effect of polyploid Arundo Donax L. on surface runoff and sediment was better than that of the natural herbaceous plants, with the intercepting efficiency higher than that of the natural herbaceous plants by 4.24% to 27.80% and 93.77% to 94.82%, respectively; compared with the arborvitae-herbaceous plants, polyploid Arundo Donax L.’s interception efficiency of surface runoff was higher by 3.95% to 29.27%, but its interception performance on the sediment was nearly equal. 2) the interception efficiencies of total nitrogen, total phosphorus and ammonia nitrogen by polyploid Arundo Donax L. were 4.19% to 29.70%, 64.56% to 95.00%, and 59.22% to 76.52% higher than those of natural herbaceous plants, and 89.41% to 98.09%, 85.03% to 95.00%, and 89.41% to 99.07% higher than those of arboreal-herbaceous plants. The study proved that polyploid Arundo Donax L. could effectively intercept runoff, sediment, and nitrogen and phosphorus, and had a high capacity for soil and water conservation, and non-point source pollution interception in the hilly area of western Henan.
To investigate the ecological management effect of polyploid Arundo Donax L. in the hilly area of western Henan, polyploid Arundo Donax L., natural herbaceous plant and arborvitae-herbaceous plants runoff plots were set up in Miaoyuan Village, Yima City, Sanmenxia, and the intercepting and controlling effect of polyploid Arundo Donax L. on surface runoff, sediment, nitrogen and phosphorus was analyzed through three rainfall comparison. The results showed that: 1) the intercepting effect of polyploid Arundo Donax L. on surface runoff and sediment was better than that of the natural herbaceous plants, with the intercepting efficiency higher than that of the natural herbaceous plants by 4.24% to 27.80% and 93.77% to 94.82%, respectively; compared with the arborvitae-herbaceous plants, polyploid Arundo Donax L.’s interception efficiency of surface runoff was higher by 3.95% to 29.27%, but its interception performance on the sediment was nearly equal. 2) the interception efficiencies of total nitrogen, total phosphorus and ammonia nitrogen by polyploid Arundo Donax L. were 4.19% to 29.70%, 64.56% to 95.00%, and 59.22% to 76.52% higher than those of natural herbaceous plants, and 89.41% to 98.09%, 85.03% to 95.00%, and 89.41% to 99.07% higher than those of arboreal-herbaceous plants. The study proved that polyploid Arundo Donax L. could effectively intercept runoff, sediment, and nitrogen and phosphorus, and had a high capacity for soil and water conservation, and non-point source pollution interception in the hilly area of western Henan.
2024,
42(12):
66-72.
doi: 10.13205/j.hjgc.202412009
Abstract:
The fluorescence components, molecular characteristics and sources of DOM in secondary effluent of municipal sewage treatment plants were revealed by three-dimensional fluorescence spectrophotometry and ultraviolet spectrophotometry with parallel factor analysis and correlation analysis, providing a data basis for the study of DOM molecular composition and source characteristics in aquatic environment. The results showed that the DOM in secondary effluent mainly contained one type of proteinoid (tryptophan-like) and more than two kinds of humus-like. There was a significant negative correlation between the content of proteinoid (corresponding to peak T1 and T2) and humus-like (corresponding to peak A and C) in DOM (P＜0.01 or P＜0.05). TCOD, SCOD and DOC were negatively correlated with the values of SUVA254 and SUVA260 (r=-0.65 to -0.96, P＜0.01 or P＜0.05), respectively. The fluorescence index (FI), biological index (BIX), humification index (HIX) and r(T/C) values of DOM were 1.96 to 2.19, 1.02 to 1.18, 1.82 to 3.27 and 2.25 to 2.95, respectively. The FI and BIX values changed relatively less, while the HIX value changed relatively greatly. There were differences in the composition and molecular properties of DOM in secondary effluent from different municipal wastewater treatment plants. The DOM came from endogenous biological origin, and the organic matter was newly produced with a weak humification degree. The DOM was humus-like-dominated, mainly derived from feces and biodegradation products, etc.
The fluorescence components, molecular characteristics and sources of DOM in secondary effluent of municipal sewage treatment plants were revealed by three-dimensional fluorescence spectrophotometry and ultraviolet spectrophotometry with parallel factor analysis and correlation analysis, providing a data basis for the study of DOM molecular composition and source characteristics in aquatic environment. The results showed that the DOM in secondary effluent mainly contained one type of proteinoid (tryptophan-like) and more than two kinds of humus-like. There was a significant negative correlation between the content of proteinoid (corresponding to peak T1 and T2) and humus-like (corresponding to peak A and C) in DOM (P＜0.01 or P＜0.05). TCOD, SCOD and DOC were negatively correlated with the values of SUVA254 and SUVA260 (r=-0.65 to -0.96, P＜0.01 or P＜0.05), respectively. The fluorescence index (FI), biological index (BIX), humification index (HIX) and r(T/C) values of DOM were 1.96 to 2.19, 1.02 to 1.18, 1.82 to 3.27 and 2.25 to 2.95, respectively. The FI and BIX values changed relatively less, while the HIX value changed relatively greatly. There were differences in the composition and molecular properties of DOM in secondary effluent from different municipal wastewater treatment plants. The DOM came from endogenous biological origin, and the organic matter was newly produced with a weak humification degree. The DOM was humus-like-dominated, mainly derived from feces and biodegradation products, etc.
2024,
42(12):
73-78.
doi: 10.13205/j.hjgc.202412010
Abstract:
Sediment is a vital component of river and lake aquatic ecosystems, the repeated migration of pollutants between the sediment and overlying water bodies has become the crux of water environment management. This experiment studied the coupling of submerged plants and benthic animals to purify sediment to reduce the impact of sediment pollutants on water bodies. The research showed that the highest performance in removal of pollutants from sediment was achieved when combining 50% sediment coverage of Vallisneria natans with 2 kg/m2 of freshwater mussels. The removal rates were 12.2% for organic matter, 25.3% for NO-2-N, 29.1% for NO-3-N, 54.4% for NH+4-N, and 16.20% for TP. The removal rates of organic matter, TN, NO-2-N, NO-3-N, NH+4-N and TP were 29.4%, 29.8%, 86.5%, 67.1%, 70.2%, 28.2% respectively, when adding biochar with 5% dry weight of sediment to the sediment, under 20 ℃. When aeration was conducted and the aeration rate was 6 L/min, the removal rates of organic matter, TN, NO-2-N, NO-3-N, NH+4-N and TP in the sediment of the combination reached 23.5%, 39.1%, 92.1%, 77.7%, 71.8% and 17.3%, respectively.
Sediment is a vital component of river and lake aquatic ecosystems, the repeated migration of pollutants between the sediment and overlying water bodies has become the crux of water environment management. This experiment studied the coupling of submerged plants and benthic animals to purify sediment to reduce the impact of sediment pollutants on water bodies. The research showed that the highest performance in removal of pollutants from sediment was achieved when combining 50% sediment coverage of Vallisneria natans with 2 kg/m2 of freshwater mussels. The removal rates were 12.2% for organic matter, 25.3% for NO-2-N, 29.1% for NO-3-N, 54.4% for NH+4-N, and 16.20% for TP. The removal rates of organic matter, TN, NO-2-N, NO-3-N, NH+4-N and TP were 29.4%, 29.8%, 86.5%, 67.1%, 70.2%, 28.2% respectively, when adding biochar with 5% dry weight of sediment to the sediment, under 20 ℃. When aeration was conducted and the aeration rate was 6 L/min, the removal rates of organic matter, TN, NO-2-N, NO-3-N, NH+4-N and TP in the sediment of the combination reached 23.5%, 39.1%, 92.1%, 77.7%, 71.8% and 17.3%, respectively.
2024,
42(12):
79-88.
doi: 10.13205/j.hjgc.202412011
Abstract:
Increasing saline wastewater discharge poses a challenge to denitrification by heterotrophic and sulfur autotrophic denitrification (HSAD). The response mechanisms and feasible mitigation strategies of heterotrophic denitrifying microorganisms to high salt stress need to be further explored. In this study, it was found that a salinity of 2% increased denitrification efficiency. However, the denitrification performance of HSAD significantly decreased when salinity increased to 6%, NO-3-N removal decreased from 95.77% to 38.01%, and the contribution of sulfur autotrophic denitrification (SAD) continued to be higher than that of heterotrophic denitrification (HD). High salinity stimulation resulted in nicotinamide adenine dinucleotide content and adenosine triphosphate levels decreasing by 10.74%, 46.6% and 56.28% respectively, at 6% salinity. In addition, the reduced activities of denitrifying enzymes (nitrate reductase and nitrite reductase) and the decrease in denitrifying functional bacteria were also important factors contributing to the inhibition of HSAD denitrification under high salt stress. Notably, adding 250 mg/L ectoine at 6% salinity alleviated the salinity stress, and enhanced the denitrification efficiency of HSAD by promoting the secretion of extracellular polymeric substances and increasing the metabolic activities of HSAD microorganisms. Microbial community analysis showed that the abundance of HD-functional bacteria increased by 3.99% compared to the case without ectoine, highlighting the key regulatory role of ectoine on community succession and stability. The results of this study deepened the understanding of the inhibition mechanism of HSAD by high-salt wastewater, and provided a feasible technical solution for sulfur-based mixotrophic denitrification technology to alleviate salt stress.
Increasing saline wastewater discharge poses a challenge to denitrification by heterotrophic and sulfur autotrophic denitrification (HSAD). The response mechanisms and feasible mitigation strategies of heterotrophic denitrifying microorganisms to high salt stress need to be further explored. In this study, it was found that a salinity of 2% increased denitrification efficiency. However, the denitrification performance of HSAD significantly decreased when salinity increased to 6%, NO-3-N removal decreased from 95.77% to 38.01%, and the contribution of sulfur autotrophic denitrification (SAD) continued to be higher than that of heterotrophic denitrification (HD). High salinity stimulation resulted in nicotinamide adenine dinucleotide content and adenosine triphosphate levels decreasing by 10.74%, 46.6% and 56.28% respectively, at 6% salinity. In addition, the reduced activities of denitrifying enzymes (nitrate reductase and nitrite reductase) and the decrease in denitrifying functional bacteria were also important factors contributing to the inhibition of HSAD denitrification under high salt stress. Notably, adding 250 mg/L ectoine at 6% salinity alleviated the salinity stress, and enhanced the denitrification efficiency of HSAD by promoting the secretion of extracellular polymeric substances and increasing the metabolic activities of HSAD microorganisms. Microbial community analysis showed that the abundance of HD-functional bacteria increased by 3.99% compared to the case without ectoine, highlighting the key regulatory role of ectoine on community succession and stability. The results of this study deepened the understanding of the inhibition mechanism of HSAD by high-salt wastewater, and provided a feasible technical solution for sulfur-based mixotrophic denitrification technology to alleviate salt stress.
2024,
42(12):
89-96.
doi: 10.13205/j.hjgc.202412012
Abstract:
The phosphorus and nitrogen removal by partial nitrification-denitrification of A2/O with different C/N ratios (2.5~7.0), were investigated under a low dissolved oxygen condition (0.5mg/L). Results showed that 80% of the influent COD was used for synthesizing PHA in the anaerobic zone. When the C/N ratio was below 4.5, the effluent COD fluctuated with the influent. TN was mainly removed by partial nitrification, endogenous denitrification, and denitrifying phosphorus removal process. When the C/N ratio was 2.5 and 3.5, the TN removal both remained at a level of 80%. The average accumulation rate of nitrite reached 24.4% and 31.9% respectively, under a C/N ratio of 4.5 and 5.0. The effluent TN stably reached 10 mg/L below with a maximum removal rate of 85.3%. Therefore, Increasing the influent C/N appropriately could effectively improve TN removal. Phosphorus was mainly removed through the denitrifying phosphorus removal process. When the C/N ratio was 2.5, the phosphorus removal rate was reduced to 65%. When the C/N ratio was 3.5, the effluent phosphorus concentration was 0.3 mg/L, achieving the best phosphorus removal rate of 92.1%. The anoxic phosphorus uptake took up 74.6% of the total removal. It was found that when the influent C/N of the system was within 5.0 to 7.0, the coupled operation of denitrifying phosphorus removal, endogenous denitrification, partial nitrification, and aerobic phosphorus absorption in the system effectively achieved synchronous and efficient removal of organic matter, phosphorus, and nitrogen, with a removal rate of 84%, 85%, and 90%, respectively. Through the 16S rDNA high-throughput sequencing analysis, the microorganisms that play a role in nitrogen and phosphorus removal in the A2/O system were mainly polysaccharide bacterium, Candidatus Competitor, denitrifying bacteria, Azospira, Nitrobacteria, Nitrospira, Nitrosomonas, and denitrifying phosphorus accumulating bacteria, Hypomicrobium and Candidatus Accumulibacter.
The phosphorus and nitrogen removal by partial nitrification-denitrification of A2/O with different C/N ratios (2.5~7.0), were investigated under a low dissolved oxygen condition (0.5mg/L). Results showed that 80% of the influent COD was used for synthesizing PHA in the anaerobic zone. When the C/N ratio was below 4.5, the effluent COD fluctuated with the influent. TN was mainly removed by partial nitrification, endogenous denitrification, and denitrifying phosphorus removal process. When the C/N ratio was 2.5 and 3.5, the TN removal both remained at a level of 80%. The average accumulation rate of nitrite reached 24.4% and 31.9% respectively, under a C/N ratio of 4.5 and 5.0. The effluent TN stably reached 10 mg/L below with a maximum removal rate of 85.3%. Therefore, Increasing the influent C/N appropriately could effectively improve TN removal. Phosphorus was mainly removed through the denitrifying phosphorus removal process. When the C/N ratio was 2.5, the phosphorus removal rate was reduced to 65%. When the C/N ratio was 3.5, the effluent phosphorus concentration was 0.3 mg/L, achieving the best phosphorus removal rate of 92.1%. The anoxic phosphorus uptake took up 74.6% of the total removal. It was found that when the influent C/N of the system was within 5.0 to 7.0, the coupled operation of denitrifying phosphorus removal, endogenous denitrification, partial nitrification, and aerobic phosphorus absorption in the system effectively achieved synchronous and efficient removal of organic matter, phosphorus, and nitrogen, with a removal rate of 84%, 85%, and 90%, respectively. Through the 16S rDNA high-throughput sequencing analysis, the microorganisms that play a role in nitrogen and phosphorus removal in the A2/O system were mainly polysaccharide bacterium, Candidatus Competitor, denitrifying bacteria, Azospira, Nitrobacteria, Nitrospira, Nitrosomonas, and denitrifying phosphorus accumulating bacteria, Hypomicrobium and Candidatus Accumulibacter.
2024,
42(12):
97-107.
doi: 10.13205/j.hjgc.202412013
Abstract:
Pyrite (FeS2) is one of the predominant minerals found on the Earth’s surface, commonly used as the fundamental mineral source for sulfur extraction and sulfuric acid production. Additionally, it serves as a natural material for wastewater treatment. Autotrophic denitrification, where pyrite acts as an electron donor, presents a bio-based treatment technology with significant potential for addressing low C/N water conditions. This approach offers advantages such as cost-effectiveness, independence from external carbon sources, reduced sludge generation, and minimal by-product formation. Furthermore, it can be synergistically integrated with various denitrification technologies. This paper provides a comprehensive examination of the principles underlying autotrophic denitrification utilizing pyrite as an electron donor, elucidating the effects of specific surface area, pH, temperature, dissolved oxygen concentration, hydraulic retention time, and the influence of toxic substances on the efficiency of pyrite-based autotrophic denitrification. Moreover, it offers a crucial overview of treatment processes and the current application landscape focused on pyrite-driven autotrophic denitrification. This includes detailed discussions on treatment methodologies such as filled bed, fluidized bed, constructed wetland, and biological filter systems that leverage pyrite autotrophic denitrification. The paper also explores the integration of pyrite autotrophic denitrification with anaerobic ammonia oxidation and heterotrophic denitrification, showcasing its efficacy in groundwater remediation and advanced sewage treatment scenarios. Lastly, the paper outlines prospective directions for advancing this technology, while critically evaluating the limitations of current application and recommending key research priorities from diverse perspectives.
Pyrite (FeS2) is one of the predominant minerals found on the Earth’s surface, commonly used as the fundamental mineral source for sulfur extraction and sulfuric acid production. Additionally, it serves as a natural material for wastewater treatment. Autotrophic denitrification, where pyrite acts as an electron donor, presents a bio-based treatment technology with significant potential for addressing low C/N water conditions. This approach offers advantages such as cost-effectiveness, independence from external carbon sources, reduced sludge generation, and minimal by-product formation. Furthermore, it can be synergistically integrated with various denitrification technologies. This paper provides a comprehensive examination of the principles underlying autotrophic denitrification utilizing pyrite as an electron donor, elucidating the effects of specific surface area, pH, temperature, dissolved oxygen concentration, hydraulic retention time, and the influence of toxic substances on the efficiency of pyrite-based autotrophic denitrification. Moreover, it offers a crucial overview of treatment processes and the current application landscape focused on pyrite-driven autotrophic denitrification. This includes detailed discussions on treatment methodologies such as filled bed, fluidized bed, constructed wetland, and biological filter systems that leverage pyrite autotrophic denitrification. The paper also explores the integration of pyrite autotrophic denitrification with anaerobic ammonia oxidation and heterotrophic denitrification, showcasing its efficacy in groundwater remediation and advanced sewage treatment scenarios. Lastly, the paper outlines prospective directions for advancing this technology, while critically evaluating the limitations of current application and recommending key research priorities from diverse perspectives.
2024,
42(12):
108-115.
doi: 10.13205/j.hjgc.202412014
Abstract:
In response to the water environment pollution caused by direct discharge of polluted rainwater into water bodies, an integrated collection and purification facility of rainwater was developed based on physical-chemical treatment in an unattended manner. The enhanced coagulation and sedimentation had been conducted onto the polluted rainwater by the facility’s operations such as rainwater collection, coagulant addition, aeration stirring and sedimentation. The study results showed that when PAC, with dosages of 150, 200, and 250 mg/L were respectively added to the polluted rainwater of three different concentrations, and the hydraulic retention time was 4.5 hours, the removal efficiencies of SS, COD and TP were more than 95%, 75% and 72%, respectively. The SS, COD and TP in effluent met the Class I-B standard of GB 18918—2002. Meanwhile, over 82% of total zinc and total lead removal rates were achieved by the facility, and the removal efficiency for total aluminum was 73% above. Moreover, the mass concentration of total zinc and total lead in the effluent of the facility was much lower than the maximum allowable emission concentration in GB 18918—2002. Additionally, the peak mass concentration of dissolved oxygen could reach 9.04 mg/L during the aeration stirring phase. The mass concentration of dissolved oxygen in discharged water was 3.75 mg/L. The treatment cost of the facility was RMB 0.08~0.11 yuan/m3 of polluted rainwater. The processes of mixing, reaction and separation were integrated through the facility, which realized the requirements of technical feasibility and economic rationality.
In response to the water environment pollution caused by direct discharge of polluted rainwater into water bodies, an integrated collection and purification facility of rainwater was developed based on physical-chemical treatment in an unattended manner. The enhanced coagulation and sedimentation had been conducted onto the polluted rainwater by the facility’s operations such as rainwater collection, coagulant addition, aeration stirring and sedimentation. The study results showed that when PAC, with dosages of 150, 200, and 250 mg/L were respectively added to the polluted rainwater of three different concentrations, and the hydraulic retention time was 4.5 hours, the removal efficiencies of SS, COD and TP were more than 95%, 75% and 72%, respectively. The SS, COD and TP in effluent met the Class I-B standard of GB 18918—2002. Meanwhile, over 82% of total zinc and total lead removal rates were achieved by the facility, and the removal efficiency for total aluminum was 73% above. Moreover, the mass concentration of total zinc and total lead in the effluent of the facility was much lower than the maximum allowable emission concentration in GB 18918—2002. Additionally, the peak mass concentration of dissolved oxygen could reach 9.04 mg/L during the aeration stirring phase. The mass concentration of dissolved oxygen in discharged water was 3.75 mg/L. The treatment cost of the facility was RMB 0.08~0.11 yuan/m3 of polluted rainwater. The processes of mixing, reaction and separation were integrated through the facility, which realized the requirements of technical feasibility and economic rationality.
2024,
42(12):
116-125.
doi: 10.13205/j.hjgc.202412015
Abstract:
Gases with bad odor are produced during the landfill treatment process, and with a large production, long lifetime, and broad impact range. Among them, hydrogen sulfide and ammonia are the typical pungent gases released by landfills for municipal solid waste. To deal with odorous gases, this article used a polymer blend based on polyvinylpyrrolidone (PVP), hydroxypropyl methylcellulose (HPMC), cellulose nanofiber (CNF), and cellulose nanocrystal (CNC) as the membrane substrates. There is a strong intermolecular hydrogen bond between the carbonyl group of polyvinylpyrrolidone and the free hydroxyl group of hydroxypropyl methylcellulose, forming a miscible blend throughout the entire composition range with good compatibility. The polymer mixed solution was sprayed into a film, and a simulated upflow reactor was used to isolate hydrogen sulfide and ammonia gas. Single-factor experiments were conducted, response surface analysis was designed, and the optimal composite membrane liquid ratio was obtained as follows: 4.20% PVP, 1.20% HPMC, 0.40% CNF, and 0.06% CNC. A plasticizer of 1.5% glycerol, a surfactant of 1.0% Tween 80, a fly repellent and deodorant of 3.0% limonene, and a fragrance of 0.5% tea tree essential oil were added to optimize the comprehensive performance of the composite membrane. The retention rate of H2S and NH3 in the composite membrane can be guaranteed to be 95% above in 30 minutes.
Gases with bad odor are produced during the landfill treatment process, and with a large production, long lifetime, and broad impact range. Among them, hydrogen sulfide and ammonia are the typical pungent gases released by landfills for municipal solid waste. To deal with odorous gases, this article used a polymer blend based on polyvinylpyrrolidone (PVP), hydroxypropyl methylcellulose (HPMC), cellulose nanofiber (CNF), and cellulose nanocrystal (CNC) as the membrane substrates. There is a strong intermolecular hydrogen bond between the carbonyl group of polyvinylpyrrolidone and the free hydroxyl group of hydroxypropyl methylcellulose, forming a miscible blend throughout the entire composition range with good compatibility. The polymer mixed solution was sprayed into a film, and a simulated upflow reactor was used to isolate hydrogen sulfide and ammonia gas. Single-factor experiments were conducted, response surface analysis was designed, and the optimal composite membrane liquid ratio was obtained as follows: 4.20% PVP, 1.20% HPMC, 0.40% CNF, and 0.06% CNC. A plasticizer of 1.5% glycerol, a surfactant of 1.0% Tween 80, a fly repellent and deodorant of 3.0% limonene, and a fragrance of 0.5% tea tree essential oil were added to optimize the comprehensive performance of the composite membrane. The retention rate of H2S and NH3 in the composite membrane can be guaranteed to be 95% above in 30 minutes.
2024,
42(12):
126-135.
doi: 10.13205/j.hjgc.202412016
Abstract:
Sulfur-containing compounds released from the combustion of fuel oil have led to serious environmental pollution and ecological deterioration. In this study, a transition metal TM-Y/MIL-101 (TM=Ni, Ag and Cu) adsorbent was prepared, where transition metal (Ni, Ag and Cu) and rare earth element yttrium were selected as exchange ions for modification. The structure, morphology and metal valence of as-prepared adsorbents were characterized. Thiophene was selected to investigate the desulfurization performance of the prepared adsorbents. Langmuir and Freundlich models were used to analyze the adsorption equilibrium properties of thiophene with different adsorbents, study the adsorption kinetics and mechanism, and investigate the control steps of the adsorption rate. Results showed that TM-Y/MIL-101 adsorbents modified by different TMs had maintained the lattice structure of MIL-101, and Cu and Ag existed with a valence of +1, while Ni existed with a valence of +2. Furthermore, the rare earth metal Y existed in the valence state of +3. The adsorption process of thiophene by TM-Y/MIL-101 complied with the Langmuir model and the Cu-Y/MIL-101 possessed the highest adsorption capacity (28.2 mg/g) and anti-aromatic adsorption desulfurization selectivity. Their adsorption performance decreased in the order of Cu-Y/MIL-101 > Ag-Y/MIL-101 > Ni-Y/MIL-101. Both pseudo-first and second-order could describe the adsorption of thiophene onto TM-Y/MIL-101. The mass transfer was found to be the control step of the adsorption process, which was controlled by the film diffusion and internal diffusion of adsorbate. The fast adsorption of thiophene molecule on TM-Y/MIL-101 could be ascribed to the S-M interaction between Y3+ and S in thiophene, π complexation between transition metal ions (Ni2+, Ag+ and Cu+) and thiophene ring, and π-π interaction between aromatic rings of MIL-101 and thiophene molecule.
Sulfur-containing compounds released from the combustion of fuel oil have led to serious environmental pollution and ecological deterioration. In this study, a transition metal TM-Y/MIL-101 (TM=Ni, Ag and Cu) adsorbent was prepared, where transition metal (Ni, Ag and Cu) and rare earth element yttrium were selected as exchange ions for modification. The structure, morphology and metal valence of as-prepared adsorbents were characterized. Thiophene was selected to investigate the desulfurization performance of the prepared adsorbents. Langmuir and Freundlich models were used to analyze the adsorption equilibrium properties of thiophene with different adsorbents, study the adsorption kinetics and mechanism, and investigate the control steps of the adsorption rate. Results showed that TM-Y/MIL-101 adsorbents modified by different TMs had maintained the lattice structure of MIL-101, and Cu and Ag existed with a valence of +1, while Ni existed with a valence of +2. Furthermore, the rare earth metal Y existed in the valence state of +3. The adsorption process of thiophene by TM-Y/MIL-101 complied with the Langmuir model and the Cu-Y/MIL-101 possessed the highest adsorption capacity (28.2 mg/g) and anti-aromatic adsorption desulfurization selectivity. Their adsorption performance decreased in the order of Cu-Y/MIL-101 > Ag-Y/MIL-101 > Ni-Y/MIL-101. Both pseudo-first and second-order could describe the adsorption of thiophene onto TM-Y/MIL-101. The mass transfer was found to be the control step of the adsorption process, which was controlled by the film diffusion and internal diffusion of adsorbate. The fast adsorption of thiophene molecule on TM-Y/MIL-101 could be ascribed to the S-M interaction between Y3+ and S in thiophene, π complexation between transition metal ions (Ni2+, Ag+ and Cu+) and thiophene ring, and π-π interaction between aromatic rings of MIL-101 and thiophene molecule.
2024,
42(12):
136-144.
doi: 10.13205/j.hjgc.202412017
Abstract:
To analyze the pollution characteristics and main sources of atmospheric fine particulate matter (PM2.5) in typical industrial cities during autumn and winter in Henan Province, taking Xuchang as an example, PM2.5 samples were collected from four sites in Xuchang from October 2019 to January 2020, and the concentrations, carbon components, inorganic elements and water-soluble ions of PM2.5 were analyzed. The results showed that the daily concentration of PM2.5 in Xuchang ranged from 16.2 μg/m3 to 222.1 μg/m3, and the daily average concentration was 86.0 μg/m3, which was 1.1 times of the limiting value specified in Ambient Air Quality Standards (GB 3095—2012) (75 μg/m3). The average value of organic carbon/elemental carbon (OC/EC) in the composition was 9.0, and sulfur oxidation rate (SOR) and nitrogen oxidation rate (NOR) were significantly greater than 0.1, indicating that PM2.5 in Xuchang was affected by secondary transformation; the most important water-soluble ions such as SO2-4, NO-3 and NH+4, accounted for 41.3% of the total mass concentration of PM2.5. Enrichment factor analysis showed that the enrichment factor (EF) values of Sb, Sn, Bi, Br, Zn, Pb, Cs, and Cu were all higher than 100, possibly due to the influence of coal combustion and idling vehicle emissions. Positive matrix factor (PMF) analysis proved that PM2.5 in Xuchang during the study period was mainly derived from secondary inorganic sources, combustion sources and vehicle sources, with a contribution rate of 38.6%, 19.9%, and 14.1%, respectively. Apart from local pollutant accumulation and transformation, regional contribution from cities such as Luohe, Kaifeng, Pingdingshan, and surrounding areas of Henan Province was also significant factor contributing to PM2.5 pollution in Xuchang.
To analyze the pollution characteristics and main sources of atmospheric fine particulate matter (PM2.5) in typical industrial cities during autumn and winter in Henan Province, taking Xuchang as an example, PM2.5 samples were collected from four sites in Xuchang from October 2019 to January 2020, and the concentrations, carbon components, inorganic elements and water-soluble ions of PM2.5 were analyzed. The results showed that the daily concentration of PM2.5 in Xuchang ranged from 16.2 μg/m3 to 222.1 μg/m3, and the daily average concentration was 86.0 μg/m3, which was 1.1 times of the limiting value specified in Ambient Air Quality Standards (GB 3095—2012) (75 μg/m3). The average value of organic carbon/elemental carbon (OC/EC) in the composition was 9.0, and sulfur oxidation rate (SOR) and nitrogen oxidation rate (NOR) were significantly greater than 0.1, indicating that PM2.5 in Xuchang was affected by secondary transformation; the most important water-soluble ions such as SO2-4, NO-3 and NH+4, accounted for 41.3% of the total mass concentration of PM2.5. Enrichment factor analysis showed that the enrichment factor (EF) values of Sb, Sn, Bi, Br, Zn, Pb, Cs, and Cu were all higher than 100, possibly due to the influence of coal combustion and idling vehicle emissions. Positive matrix factor (PMF) analysis proved that PM2.5 in Xuchang during the study period was mainly derived from secondary inorganic sources, combustion sources and vehicle sources, with a contribution rate of 38.6%, 19.9%, and 14.1%, respectively. Apart from local pollutant accumulation and transformation, regional contribution from cities such as Luohe, Kaifeng, Pingdingshan, and surrounding areas of Henan Province was also significant factor contributing to PM2.5 pollution in Xuchang.
2024,
42(12):
145-154.
doi: 10.13205/j.hjgc.202412018
Abstract:
The DGEN380 engine was chosen as a representative turbofan engine for jet business aircrafts, and the emission characteristics of gaseous pollutants and particulate matter from this engine were tested on December 23, 2023, at multiple operating conditions (including three operating conditions at a thrust level of 10%, 30%, and 45%). The results indicated that 1) NO and NOx emission factors increased significantly with increasing thrust level, while the emission factors of NO2 and CO showed a decreasing trend. Under the 10% thrust condition, the particle size distribution of particulate matter exhibited a bimodal pattern, with two peaks at 20 nm and 100 nm. The total number concentration of particles was found to be 3.4 to 3.9 times higher than that under 30% and 45% thrust conditions. 2) Further analysis of the composition of particulate matter fractions in different size ranges revealed high emission factors for Na, Mg, Fe, S, and Cu elements in the particulate matter. These elements accounted for more than 80% of the total composition at various thrust levels. The organic carbon component had the highest proportion as OC3 (25.67% to 56.56%), which varied significantly with engine thrust level; meanwhile, elemental carbon (EC) content remained relatively stable across all thrust levels. 3) Ionic components were predominantly composed of SO2-4, NO-3, and Cl-, with average emission factors ranging from 0.24 mg/kg to 1.60 mg/kg across all three thrust levels. 4) A stepwise regression analysis linking pollutant emissions concentrations to engine parameters revealed that average combustion chamber inlet temperature was a key factor influencing CO emissions; NO and NOx emission concentrations were positively correlated with lube oil flow rate; while particulate matter emissions showed a negative correlation with both average combustion chamber inlet temperature and inlet pressure. These findings can provide effective data for assessing pollutant emission characteristics in jet business aircraft, and offer scientific insights for preventing and controlling air pollution at airports serving such aircrafts.
The DGEN380 engine was chosen as a representative turbofan engine for jet business aircrafts, and the emission characteristics of gaseous pollutants and particulate matter from this engine were tested on December 23, 2023, at multiple operating conditions (including three operating conditions at a thrust level of 10%, 30%, and 45%). The results indicated that 1) NO and NOx emission factors increased significantly with increasing thrust level, while the emission factors of NO2 and CO showed a decreasing trend. Under the 10% thrust condition, the particle size distribution of particulate matter exhibited a bimodal pattern, with two peaks at 20 nm and 100 nm. The total number concentration of particles was found to be 3.4 to 3.9 times higher than that under 30% and 45% thrust conditions. 2) Further analysis of the composition of particulate matter fractions in different size ranges revealed high emission factors for Na, Mg, Fe, S, and Cu elements in the particulate matter. These elements accounted for more than 80% of the total composition at various thrust levels. The organic carbon component had the highest proportion as OC3 (25.67% to 56.56%), which varied significantly with engine thrust level; meanwhile, elemental carbon (EC) content remained relatively stable across all thrust levels. 3) Ionic components were predominantly composed of SO2-4, NO-3, and Cl-, with average emission factors ranging from 0.24 mg/kg to 1.60 mg/kg across all three thrust levels. 4) A stepwise regression analysis linking pollutant emissions concentrations to engine parameters revealed that average combustion chamber inlet temperature was a key factor influencing CO emissions; NO and NOx emission concentrations were positively correlated with lube oil flow rate; while particulate matter emissions showed a negative correlation with both average combustion chamber inlet temperature and inlet pressure. These findings can provide effective data for assessing pollutant emission characteristics in jet business aircraft, and offer scientific insights for preventing and controlling air pollution at airports serving such aircrafts.
2024,
42(12):
155-165.
doi: 10.13205/j.hjgc.202412019
Abstract:
The solution absorption method is an effective measure to solve the pollution of particulate matter and H2S odor in sewage treatment plants and landfills. However, the non-recycling of absorbent hindered the promotion and use of adsorption method. In this study, a coupling process of solution absorption and electro-Fenton was designed to absorb pollutants by tiny bubbles generated by polypyrrole film, the effects of gas flow rate and functional solution type on the absorption efficiency of H2S and particulate matter were investigated and the reaction kinetics was analyzed. Meanwhile, the oxidation effect on sulfide, mechanism of absorption and oxidation, and the reusability of the coupling process of solution absorption, and electro-Fenton was also explored. The results showed that the absorption rates of H2S and particulate matter could reach 89.5% and 92.7% in 7 hours respectively, under the condition of an air flow rate of 85 mL/min and Na2SO4+FeSO4 as the functional solution, and the absorption processes followed the first-order kinetic model; the maximum removal rate of S2- by electro-Fenton reached 96.7% in 60 minutes and the final oxidation product was SO2-4; the coupling process of solution absorption and electro-Fenton showed ideal characteristic of adsorption, oxidation and cyclic stability, and has a large potential application for odor treatment.
The solution absorption method is an effective measure to solve the pollution of particulate matter and H2S odor in sewage treatment plants and landfills. However, the non-recycling of absorbent hindered the promotion and use of adsorption method. In this study, a coupling process of solution absorption and electro-Fenton was designed to absorb pollutants by tiny bubbles generated by polypyrrole film, the effects of gas flow rate and functional solution type on the absorption efficiency of H2S and particulate matter were investigated and the reaction kinetics was analyzed. Meanwhile, the oxidation effect on sulfide, mechanism of absorption and oxidation, and the reusability of the coupling process of solution absorption, and electro-Fenton was also explored. The results showed that the absorption rates of H2S and particulate matter could reach 89.5% and 92.7% in 7 hours respectively, under the condition of an air flow rate of 85 mL/min and Na2SO4+FeSO4 as the functional solution, and the absorption processes followed the first-order kinetic model; the maximum removal rate of S2- by electro-Fenton reached 96.7% in 60 minutes and the final oxidation product was SO2-4; the coupling process of solution absorption and electro-Fenton showed ideal characteristic of adsorption, oxidation and cyclic stability, and has a large potential application for odor treatment.
2024,
42(12):
166-173.
doi: 10.13205/j.hjgc.202412020
Abstract:
Hydrothermal carbonization technology is a potential technology for the resource utilization of municipal sludge. As the main product, sludge-derived hydrochar can be used as an adsorbent for wastewater treatment. However, the effects of flocculant addition in sludge dewatering on formation and adsorption characteristics of sludge-derived hydrochar are still unclear. Therefore, in this study, three typical flocculants (polyaluminum chloride, polyferric sulfate, and polyacrylamide) were added to municipal sludge and incubated at 180 ℃ for 4 h to prepare three kinds of sludge-derived hydrochar. After that, methylene blue and tetracycline were used as simulated pollutants to investigate the effects of flocculant addition on the yield and adsorption characteristics of sludge-derived hydrochar. The results showed that different flocculants could affect not only the yield but also the adsorption characteristics of sludge-derived hydrochar. In detail, the yield of hydrochar was up to 70.14% after adding polyaluminum chloride, which was significantly improved compared with 65.35% in the blank group. In terms of adsorption, when the target pollutant was tetracycline, polyferric sulfate had a great influence on the adsorption behavior of sludge-derived hydrochar, and the adsorption capacity was up to 47.89 mg/g. When the target pollutant was methylene blue, polyacrylamide had a great influence on the adsorption behavior of sludge-derived hydrochar, and the adsorption capacity reached 23.39 mg/g. This study can provide theoretical support for effective utilization of sludge-derived hydrochar.
Hydrothermal carbonization technology is a potential technology for the resource utilization of municipal sludge. As the main product, sludge-derived hydrochar can be used as an adsorbent for wastewater treatment. However, the effects of flocculant addition in sludge dewatering on formation and adsorption characteristics of sludge-derived hydrochar are still unclear. Therefore, in this study, three typical flocculants (polyaluminum chloride, polyferric sulfate, and polyacrylamide) were added to municipal sludge and incubated at 180 ℃ for 4 h to prepare three kinds of sludge-derived hydrochar. After that, methylene blue and tetracycline were used as simulated pollutants to investigate the effects of flocculant addition on the yield and adsorption characteristics of sludge-derived hydrochar. The results showed that different flocculants could affect not only the yield but also the adsorption characteristics of sludge-derived hydrochar. In detail, the yield of hydrochar was up to 70.14% after adding polyaluminum chloride, which was significantly improved compared with 65.35% in the blank group. In terms of adsorption, when the target pollutant was tetracycline, polyferric sulfate had a great influence on the adsorption behavior of sludge-derived hydrochar, and the adsorption capacity was up to 47.89 mg/g. When the target pollutant was methylene blue, polyacrylamide had a great influence on the adsorption behavior of sludge-derived hydrochar, and the adsorption capacity reached 23.39 mg/g. This study can provide theoretical support for effective utilization of sludge-derived hydrochar.
2024,
42(12):
174-183.
doi: 10.13205/j.hjgc.202412021
Abstract:
Sludge is slowly frozen and then thawed, which usually greatly improves the dewatering performance of the sludge. In this paper, the dewatering effect of urban sludge was investigated based on the freeze-thaw cycle method. The response surface method was used, taking the sludge freeze-thaw temperature (℃), freeze-thaw duration (h), and freeze-thaw time (n) as the dependent variables, and the sludge moisture content (%) as the response value, and a mathematical model was established by the Box-Behnken central combination design method. The results showed that when the freeze-thaw temperature was -16.30 ℃, the freeze-thaw time was 19.70 h, and freeze-thaw for 19 cycles, the minimum sludge moisture content predicted by the model was 33.93%, and the model R2>0.99, indicating that the response surface method was feasible to optimize the physical and chemical properties of the regulated sludge during the freeze-thaw cycle to improve its dewatering performance. The hydrothermal process inside the sludge is an important factor affecting the utilization of sludge and water resources. The traditional hydrothermal coupling model ignores the water’s effect on heat transfer in the unsaturated medium, and it is still difficult to realize the numerical value of the coupling theoretical model between the water field and temperature field. The sludge freeze-thaw cycle model was established through the finite element simulation software. Based on the experimental data, the coupling of ice-water phase transition and partial differential equation of water convection was solved, and the relationship between sludge water convection and temperature change was analyzed. The microstructure and pore changes of sludge flocs was analyzed by scanning electron microscope (SEM). It provides a basis for freeze-thaw treatment in optimizing sludge dewatering performance. The results show that COMSOL software can realize flexible definitions of sludge and hydrothermal parameters, ice water phase change latent heat and boundary conditions, and can realize hydrothermal field coupling analysis.
Sludge is slowly frozen and then thawed, which usually greatly improves the dewatering performance of the sludge. In this paper, the dewatering effect of urban sludge was investigated based on the freeze-thaw cycle method. The response surface method was used, taking the sludge freeze-thaw temperature (℃), freeze-thaw duration (h), and freeze-thaw time (n) as the dependent variables, and the sludge moisture content (%) as the response value, and a mathematical model was established by the Box-Behnken central combination design method. The results showed that when the freeze-thaw temperature was -16.30 ℃, the freeze-thaw time was 19.70 h, and freeze-thaw for 19 cycles, the minimum sludge moisture content predicted by the model was 33.93%, and the model R2>0.99, indicating that the response surface method was feasible to optimize the physical and chemical properties of the regulated sludge during the freeze-thaw cycle to improve its dewatering performance. The hydrothermal process inside the sludge is an important factor affecting the utilization of sludge and water resources. The traditional hydrothermal coupling model ignores the water’s effect on heat transfer in the unsaturated medium, and it is still difficult to realize the numerical value of the coupling theoretical model between the water field and temperature field. The sludge freeze-thaw cycle model was established through the finite element simulation software. Based on the experimental data, the coupling of ice-water phase transition and partial differential equation of water convection was solved, and the relationship between sludge water convection and temperature change was analyzed. The microstructure and pore changes of sludge flocs was analyzed by scanning electron microscope (SEM). It provides a basis for freeze-thaw treatment in optimizing sludge dewatering performance. The results show that COMSOL software can realize flexible definitions of sludge and hydrothermal parameters, ice water phase change latent heat and boundary conditions, and can realize hydrothermal field coupling analysis.
2024,
42(12):
184-192.
doi: 10.13205/j.hjgc.202412022
Abstract:
As the main organic solid waste component in the urban areas, kitchen waste is produced in large quantities and causes serious pollution. Anaerobic digestion has become one of the mainstream processing technologies, which can reduce the amount of food waste and recover energy simultaneously. This paper discussed the technical risk of metabolite accumulation in the anaerobic digestion of kitchen waste, and the mechanism of inhibitory instability from a microbial perspective was analyzed. Furthermore, bioaugmentation strategies such as microecological regulation, additive supplementation, and microbial domestication are introduced to guarantee efficient biogas production and stable operation, which can provide a reference for large-scale treatment of kitchen waste.
As the main organic solid waste component in the urban areas, kitchen waste is produced in large quantities and causes serious pollution. Anaerobic digestion has become one of the mainstream processing technologies, which can reduce the amount of food waste and recover energy simultaneously. This paper discussed the technical risk of metabolite accumulation in the anaerobic digestion of kitchen waste, and the mechanism of inhibitory instability from a microbial perspective was analyzed. Furthermore, bioaugmentation strategies such as microecological regulation, additive supplementation, and microbial domestication are introduced to guarantee efficient biogas production and stable operation, which can provide a reference for large-scale treatment of kitchen waste.
2024,
42(12):
193-200.
doi: 10.13205/j.hjgc.202412023
Abstract:
At present, physical adsorption is an important technical means for marine oil pollution. Biomass adsorbent materials in the research hotspot of biomass foam have a broad application prospect because of their high porosity and rich 3-dimensional structure, but some biomass foams are complicated to prepare and the preparation process requires toxic organic solvents. In this study, a simple and green sacrificial template method was used. The leaf-PVDF porous sponge material was prepared by letting the PVDF powder melt at 180 ℃ to encapsulate the NaCl particles and leaf powder, and then washing to remove the NaCl template to form a porous structure. The water contact angle of the material in the air is 121°, and the saturated absorption capacity of various oils or organic solvents with a density of less than 0.9 g/cm3 is 350%~540%. The material also has good mechanical properties, maintaining 88% of its original height after 15 compression cycles. When the oil slick on the water surface is recovered by extrusion at room temperature, 4.28 g of pump oil can be recovered within 10 min from 0.35 grams of material, and the water surface becomes clear after recovery, and there is no obvious pump oil residue.
At present, physical adsorption is an important technical means for marine oil pollution. Biomass adsorbent materials in the research hotspot of biomass foam have a broad application prospect because of their high porosity and rich 3-dimensional structure, but some biomass foams are complicated to prepare and the preparation process requires toxic organic solvents. In this study, a simple and green sacrificial template method was used. The leaf-PVDF porous sponge material was prepared by letting the PVDF powder melt at 180 ℃ to encapsulate the NaCl particles and leaf powder, and then washing to remove the NaCl template to form a porous structure. The water contact angle of the material in the air is 121°, and the saturated absorption capacity of various oils or organic solvents with a density of less than 0.9 g/cm3 is 350%~540%. The material also has good mechanical properties, maintaining 88% of its original height after 15 compression cycles. When the oil slick on the water surface is recovered by extrusion at room temperature, 4.28 g of pump oil can be recovered within 10 min from 0.35 grams of material, and the water surface becomes clear after recovery, and there is no obvious pump oil residue.
2024,
42(12):
201-209.
doi: 10.13205/j.hjgc.202412024
Abstract:
In this paper, biochar was prepared by pyrolysis with Canna indica as raw material, and then modified with HNO3 and KOH, respectively. The structures and properties of the biochar were characterized by using scanning electron microscopy (SEM), specific surface area and porosity analyzer (SSAP), and Fourier transform infrared spectroscopy (FTIR). The adsorption performance and mechanism of sulfamethoxazole (SMX) by biochars were investigated, and the effects of pH and biochar dosage on the adsorption of SMX were investigated as well. The results showed that compared with the unmodified biochar, the specific surface area of acid/alkali modified biochar was greatly increased, the pore structure was deeply developed, and the adsorption performance was significantly improved. The adsorption process of SMX by the biochar follows the pseudo-second-order kinetics model; the Langmuir model can describe the adsorption isotherm of SMX onto acid-modified biochar better, but adsorption process one the unmodified and alkali modified biochar fit better with the Freundlich model. The adsorption process of SMX by the biochar was endothermic and spontaneous. pH and the dosage of biochar added has a significant effect on the adsorption of SMX by the biochar. The adsorption process was jointly influenced by pore filling, hydrogen bonding, π-π EDA, and electrostatic interactions.
In this paper, biochar was prepared by pyrolysis with Canna indica as raw material, and then modified with HNO3 and KOH, respectively. The structures and properties of the biochar were characterized by using scanning electron microscopy (SEM), specific surface area and porosity analyzer (SSAP), and Fourier transform infrared spectroscopy (FTIR). The adsorption performance and mechanism of sulfamethoxazole (SMX) by biochars were investigated, and the effects of pH and biochar dosage on the adsorption of SMX were investigated as well. The results showed that compared with the unmodified biochar, the specific surface area of acid/alkali modified biochar was greatly increased, the pore structure was deeply developed, and the adsorption performance was significantly improved. The adsorption process of SMX by the biochar follows the pseudo-second-order kinetics model; the Langmuir model can describe the adsorption isotherm of SMX onto acid-modified biochar better, but adsorption process one the unmodified and alkali modified biochar fit better with the Freundlich model. The adsorption process of SMX by the biochar was endothermic and spontaneous. pH and the dosage of biochar added has a significant effect on the adsorption of SMX by the biochar. The adsorption process was jointly influenced by pore filling, hydrogen bonding, π-π EDA, and electrostatic interactions.
2024,
42(12):
210-217.
doi: 10.13205/j.hjgc.202412025
Abstract:
A novel magnetic biochar aerogel (BCAFe-600) was prepared from waste corrugated paper via crushing followed by impregnation with FeCl3/ethanol solution and carbonization. The materials’ morphology, elemental composition, crystal structure, surface area, surface functional groups, mechanical property, magnetic property, hydrophilicity, and Zeta potential were analyzed and compared. The adsorption isotherm of BCAFe-600 for methylene blue was studied, and BCAFe-600 was used as a magnetic separable and floatable adsorbent for the purification of the simulated methylene blue polluted natural water. The results showed that the hydrophilic BCAFe-600 was composed of criss-crossed ribbon-like carbon fibers, and the main chemical constituents of BCAFe-600 were amorphous carbon, maghemite, and calcite. The presence of FeCl3 benefited the evolution of porous structure and the mechanical strength of BCAFe-600, and maghemite derived from FeCl3 gave magnetism to BCAFe-600, possessing a BET surface area of 205 m2/g and a saturated magnetization value of 7.62 emu/g. The Langmuir model was applicable for fitting the adsorption isotherm data for methylene blue with a maximum adsorption capacity of 35.6 mg/g, and the adsorption kinetics of methylene blue on the floatable BCAFe-600 complied with pseudo-second-order kinetics model.
A novel magnetic biochar aerogel (BCAFe-600) was prepared from waste corrugated paper via crushing followed by impregnation with FeCl3/ethanol solution and carbonization. The materials’ morphology, elemental composition, crystal structure, surface area, surface functional groups, mechanical property, magnetic property, hydrophilicity, and Zeta potential were analyzed and compared. The adsorption isotherm of BCAFe-600 for methylene blue was studied, and BCAFe-600 was used as a magnetic separable and floatable adsorbent for the purification of the simulated methylene blue polluted natural water. The results showed that the hydrophilic BCAFe-600 was composed of criss-crossed ribbon-like carbon fibers, and the main chemical constituents of BCAFe-600 were amorphous carbon, maghemite, and calcite. The presence of FeCl3 benefited the evolution of porous structure and the mechanical strength of BCAFe-600, and maghemite derived from FeCl3 gave magnetism to BCAFe-600, possessing a BET surface area of 205 m2/g and a saturated magnetization value of 7.62 emu/g. The Langmuir model was applicable for fitting the adsorption isotherm data for methylene blue with a maximum adsorption capacity of 35.6 mg/g, and the adsorption kinetics of methylene blue on the floatable BCAFe-600 complied with pseudo-second-order kinetics model.
2024,
42(12):
218-228.
doi: 10.13205/j.hjgc.202412026
Abstract:
The steel process contains abundant residual valuable components, which come from a wide range of sources and have a complex composition. It is necessary to utilize these components as resources efficiently. This article is based on the theory of metallurgical processes, analyzes the sources, transformation, and migration laws of residual components in the steel process, reveals the causal relationship between the disorder of residual components and carbon pollution emissions in the steel process, and proposes the theoretical viewpoint of self-consistent recycling of valuable components in the steel process, that is, inputting a certain amount of governance material flow and energy flow (negative entropy flow) to promote the disordered residual components and their carried residual energy to return to the main process of steel, or become raw materials for resource recycling in other industrial processes. At the same time, based on the theoretical viewpoint of self-consistent resource utilization of material energy in the steel process, typical process methods and application cases of self-consistent recycling of valuable components, such as non-metallic organic components, non-metallic inorganic components, and heavy (alkali) metal components are introduced.
The steel process contains abundant residual valuable components, which come from a wide range of sources and have a complex composition. It is necessary to utilize these components as resources efficiently. This article is based on the theory of metallurgical processes, analyzes the sources, transformation, and migration laws of residual components in the steel process, reveals the causal relationship between the disorder of residual components and carbon pollution emissions in the steel process, and proposes the theoretical viewpoint of self-consistent recycling of valuable components in the steel process, that is, inputting a certain amount of governance material flow and energy flow (negative entropy flow) to promote the disordered residual components and their carried residual energy to return to the main process of steel, or become raw materials for resource recycling in other industrial processes. At the same time, based on the theoretical viewpoint of self-consistent resource utilization of material energy in the steel process, typical process methods and application cases of self-consistent recycling of valuable components, such as non-metallic organic components, non-metallic inorganic components, and heavy (alkali) metal components are introduced.
2024,
42(12):
229-236.
doi: 10.13205/j.hjgc.202412027
Abstract:
Immobilization remediation is a commonly used remediation method for soil cadmium pollution, but there is poor research on the effect of fertilization on the immobilization remediation of soil Cd pollution. In this paper, KNO3 (K1) and KH2PO4 (K2) were added in Cd polluted soil, and sepiolite was used as an amendment. Through the rape pot experiment, the effects of adding different doses of two potassium fertilizers on the remediation effect of soil Cd pollution under the condition of sepiolite immobilization (S) were studied. The results showed that compared with S treatment, in S+K1 treatment, the soil available Cd content increased by 22.58% to 29.03%, but there was no significant difference between different doses of KNO3 added. The soil available Cd content increased by 6.45% to 32.26% in S+K2L and S+K2M treatments, but decreased with the increase of KH2PO4 addition. Compared with S treatment, the content of available Cu, Zn and Mn in soil increased by 7.83% to 11.98%, 0.54% to 6.17% and 49.13% to 63.83%, respectively, when different doses of KNO3 were added in sepiolite immobilization treatment. Adding different doses of KH2PO4 could increase the contents of available Cu, Zn and Mn in soil by 8.99% to 12.44%, 25.20% to 31.37%, and 86.65% to 94.58%, respectively. Compared with S treatment, S+K1 treatment significantly increased the cadmium content in rape shoot, with an increased rate of 31.79% to 43.16% (P<0.05), but there was no significant difference between S+K2 and S treatment. In addition, under the immobilization remediation of sepiolite, the addition of two types of potassium fertilizers also had a significant impact on Cu and Zn content in rape shoots. The research results can provide important references for scientific application of potassium fertilizer in the safe utilization of Cd-polluted farmland.
Immobilization remediation is a commonly used remediation method for soil cadmium pollution, but there is poor research on the effect of fertilization on the immobilization remediation of soil Cd pollution. In this paper, KNO3 (K1) and KH2PO4 (K2) were added in Cd polluted soil, and sepiolite was used as an amendment. Through the rape pot experiment, the effects of adding different doses of two potassium fertilizers on the remediation effect of soil Cd pollution under the condition of sepiolite immobilization (S) were studied. The results showed that compared with S treatment, in S+K1 treatment, the soil available Cd content increased by 22.58% to 29.03%, but there was no significant difference between different doses of KNO3 added. The soil available Cd content increased by 6.45% to 32.26% in S+K2L and S+K2M treatments, but decreased with the increase of KH2PO4 addition. Compared with S treatment, the content of available Cu, Zn and Mn in soil increased by 7.83% to 11.98%, 0.54% to 6.17% and 49.13% to 63.83%, respectively, when different doses of KNO3 were added in sepiolite immobilization treatment. Adding different doses of KH2PO4 could increase the contents of available Cu, Zn and Mn in soil by 8.99% to 12.44%, 25.20% to 31.37%, and 86.65% to 94.58%, respectively. Compared with S treatment, S+K1 treatment significantly increased the cadmium content in rape shoot, with an increased rate of 31.79% to 43.16% (P<0.05), but there was no significant difference between S+K2 and S treatment. In addition, under the immobilization remediation of sepiolite, the addition of two types of potassium fertilizers also had a significant impact on Cu and Zn content in rape shoots. The research results can provide important references for scientific application of potassium fertilizer in the safe utilization of Cd-polluted farmland.
2024,
42(12):
237-244.
doi: 10.13205/j.hjgc.202412028
Abstract:
In order to investigate the remediation of polycyclic aromatic hydrocarbons (PAHs) in coking-contaminated soils by using potassium permanganate (KMnO4) as the oxidant, PAHs contaminated soil in Hefei, Anhui province was taken as the experimental object. Effects of environmental factors including KMnO4 concentration, reaction time and liquid-solid ratio were determined accordingly. The results showed that: 1) with the increase of KMnO4 concentration, the removal efficiency of PAHs improved. The content of total PAHs decreased from 300.15 mg/kg to 55.80 mg/kg when KMnO4 concentration was 0.13 mmol/g, the removal efficiency of total PAHs and benzo [a] pyrene was 81.41% and 97.06%, respectively; 2) the removal efficiency of PAHs significantly increased with the prolongation of reaction time, and after 2 h of reaction, the content of total PAHs was 64.33 mg/kg, with a removal efficiency of 78.57%. When the reaction time was extended to 48 h, the removal efficiency increased to 85.65%; 3) the removal efficiency of PAHs was not significantly affected at different liquid-solid ratios; 4) response surface analysis showed that the removal efficiency of total PAHs reached the peak at 87.62% when the concentration of KMnO4 was 0.21 mmol/g, the reaction time was 32.50 h and the liquid-solid ratio was 1∶1; 5) KMnO4 can directly participate in the oxidation of PAHs or indirectly participate in the oxidation of PAHs through by-product MnO2, and convert high-ring PAHs into low-ring PAHs or various intermediates, and further decompose them into CO2 and H2O.
In order to investigate the remediation of polycyclic aromatic hydrocarbons (PAHs) in coking-contaminated soils by using potassium permanganate (KMnO4) as the oxidant, PAHs contaminated soil in Hefei, Anhui province was taken as the experimental object. Effects of environmental factors including KMnO4 concentration, reaction time and liquid-solid ratio were determined accordingly. The results showed that: 1) with the increase of KMnO4 concentration, the removal efficiency of PAHs improved. The content of total PAHs decreased from 300.15 mg/kg to 55.80 mg/kg when KMnO4 concentration was 0.13 mmol/g, the removal efficiency of total PAHs and benzo [a] pyrene was 81.41% and 97.06%, respectively; 2) the removal efficiency of PAHs significantly increased with the prolongation of reaction time, and after 2 h of reaction, the content of total PAHs was 64.33 mg/kg, with a removal efficiency of 78.57%. When the reaction time was extended to 48 h, the removal efficiency increased to 85.65%; 3) the removal efficiency of PAHs was not significantly affected at different liquid-solid ratios; 4) response surface analysis showed that the removal efficiency of total PAHs reached the peak at 87.62% when the concentration of KMnO4 was 0.21 mmol/g, the reaction time was 32.50 h and the liquid-solid ratio was 1∶1; 5) KMnO4 can directly participate in the oxidation of PAHs or indirectly participate in the oxidation of PAHs through by-product MnO2, and convert high-ring PAHs into low-ring PAHs or various intermediates, and further decompose them into CO2 and H2O.
