[Objectives] This study was conducted to solve the prominent problems in the treatment of domestic sewage in southern rural areas of China. [Methods] An integrated process treatment mode of anaerobic/anoxic/aerobic mo...[Objectives] This study was conducted to solve the prominent problems in the treatment of domestic sewage in southern rural areas of China. [Methods] An integrated process treatment mode of anaerobic/anoxic/aerobic moving bed biofilm reactor (A 2O-MBBR) was proposed to analyze and study its operating effect and influencing factors. [Results] The A^(2)O-MBBR mode had good COD removal efficiency and nitrogen and phosphorus removal performance, and the water quality index of the effluent met the Class A standard of GB181918-2002. This mode is suitable for treating rural domestic sewage, and has high treatment effects in different operating periods. In spring, the average removal rates of COD, NH_(4)^(+)-N, TN, TP and SS reached (83.53 ± 2.15)%, (89.44 ± 4.97)%, (67.36±18.53)%, (88.22±11.21)% and (91.73±2.25)%, respectively;In the autumn period, the average removal rates of COD, NH_(4)^(+)-N, TN, TP and SS were (83.49±2.64)%, (89.26±9.19)%, (66.05±17.00)%, (87.48±9.68)%, and (91.13±2.35)%. [Conclusions] This study provides theoretical reference and technical support for the popularization and application of A^(2)O-MBBR integrated process.展开更多
In recent years, the beer industry is a biological food industry that consumes a lot of water, and it has developed rapidly in China. The sewage discharged from the mass production of beer poses a huge threat to the e...In recent years, the beer industry is a biological food industry that consumes a lot of water, and it has developed rapidly in China. The sewage discharged from the mass production of beer poses a huge threat to the environment. In order to evaluate and better solve the possible environmental impacts of beer treatment engineering projects, a brewery project in Foshan City is taken as an example to investigate the water pollution generation links of the engineering process including surface water and groundwater. According to the relevant technical methods and standards, water pollution factors are screened, and concentration and discharge are monitored. Through comprehensive analysis, predictive evaluation is obtained. It is confirmed that the project meets the requirements of national laws and regulations and environmental protection standards.展开更多
Full scale experimental study on nitrogen removal for low-carbon wastewater was conducted in reversed A2/O process in Jiguanshi waste water treatment plant in Chongqing,in order to aid the operation and maintenance of...Full scale experimental study on nitrogen removal for low-carbon wastewater was conducted in reversed A2/O process in Jiguanshi waste water treatment plant in Chongqing,in order to aid the operation and maintenance of similar WWTP. When the proposed measures,such as using 0.1% (volume fraction of wastewater) landfill leachate,shortening HRT by 2/3 in the primary sedimentation tank and controlling DO at 0.5 mg/L in the 3rd section of aerobic zone,are applied,15% of the carbon source can be complemented,the favorable property of activated sludge is achieved,and the nitrogen removal effect is significantly improved. The effluent NH3-N is 2 mg/L and the removal rate is 90%. The effluent TN is 17 mg/L and the removal rate is 54%. The up-to-standard discharge of the effluent is achieved. And after the optimization,the unit electricity consumption also reaches 0.21 kW/h and saves 20%.展开更多
Thermodynamic diagrams of Na−S−Fe−H_(2)O system were constructed to analyze the behavior of sulfur and iron in the Bayer process.After digestion,iron mainly exists as Fe_(3)O_(4) and Fe_(2)O_(3) in red mud,and partial...Thermodynamic diagrams of Na−S−Fe−H_(2)O system were constructed to analyze the behavior of sulfur and iron in the Bayer process.After digestion,iron mainly exists as Fe_(3)O_(4) and Fe_(2)O_(3) in red mud,and partial iron transfers into solution as Fe(OH)_(3)^(−),HFeO_(2)^(−),Fe(OH)_(4)^(−)and Fe(OH)_(4)^(2−).The dominant species of sulfur is S^(2−),followed by SO_(4)^(2−),and then SO_(3)^(2−)and S_(2)O_(3)^(2−).The thermodynamic analysis is consistent with the iron and sulfur species distribution in the solution obtained by experiments.When the temperature decreases,sulfur and iron can combine and precipitate.Controlling low potential and reducing temperature are beneficial to removing them from the solution.XRD patterns show that NaFeS_(2)·2H_(2)O,FeS and FeS_(2) widely appear in red mud and precipitates of pyrite and high-sulfur bauxite digestion solution.Thermodynamic analysis can be utilized to guide the simultaneous removal of sulfur and iron in the Bayer process.展开更多
A bench-scale anaerobic/anoxic/aerobic process-biological aerated filter （A^2/O-BAF） combined system was carded out to treat wastewater with lower C/N and C/P ratios. The A^2/O process was operated in a short aerobi...A bench-scale anaerobic/anoxic/aerobic process-biological aerated filter （A^2/O-BAF） combined system was carded out to treat wastewater with lower C/N and C/P ratios. The A^2/O process was operated in a short aerobic sludge retention time （SRT） for organic pollutants and phosphorus removal, and denitrification. The subsequent BAF process was mainly used for nitrification. The BAF effluent was partially returned to anoxic zone of the A^2/O process to provide electron acceptors for denitrification and anoxic P uptake. This unique system formed an environment for reproducing the denitdfying phosphate-accumulating organisms （DPAOs）. The ratio of DPAOs to phosphorus accumulating organisms （PAOs） could be maintained at 28% by optimizing the organic loads in the anaerobic zone and the nitrate loads into the anoxic zone in the A^2/O process. The aerobic phosphorus over-uptake and discharge of excess activated sludge was the main mechanism of phosphorus removal in the combined system. The aerobic SRT of the A^2/O process should meet the demands for the development of aerobic PAOs and the restraint on the nitrifiers growth, and the contact time in the aerobic zone of the A^2/O process should be longer than 30 min, which ensured efficient phosphorus removal in the combined system. The adequate BAF effluent return rates should be controlled with 1--4 mg/L nitrate nitrogen in the anoxic zone effluent of A^2/O process to achieve the optimal nitrogen and phosphorus removal efficiencies.展开更多
A lab-scale anaerobic-anoxic-oxic (A2O) process used to treat a synthetic brewage wastewater was investigated. The objectives of the study were to identify the existence of denitrifying phosphorus removing bacteria (D...A lab-scale anaerobic-anoxic-oxic (A2O) process used to treat a synthetic brewage wastewater was investigated. The objectives of the study were to identify the existence of denitrifying phosphorus removing bacteria (DPB), evaluate the contribution of DPB to biological nutrient removal and enhance the denitrifying phosphorus removal in A2O bioreactors. Sludge analysis confirmed that the average anoxic P uptake accounted for approximately 70% the total amount of P uptake, and the ratio of anoxic P uptake rate to aerobic P uptake rate was 69%. In addition, nitrate concentration in the anoxic phase and different organic substrate introduced into the anaerobic phase had significant effect on the anoxic P uptake. Compared with conventional A2O processes, good removal efficiencies of COD, phosphorus, ammonia and total nitrogen (92.3%, 95.5%, 96% and 79.5%, respectively) could be achieved in the anoxic P uptake system, and aeration energy consumption was saved 25%. By controlling the nitrate recirculation flow in the anoxic zone, anoxic P uptake could be enhanced, which solved the competition for organic substrates among poly-P organisms and denitrifiers successfully under the COD limiting conditions. Therefore, in wastewater treatment plants the control system should be applied according to the practical situation to optimize the operation.展开更多
Because of the highly toxic cyanide in the gold cyanide residues,cyanide must be removed for environmental protection.The process mineralogy of residues was studied firstly,and then cyanide removal was carried out by ...Because of the highly toxic cyanide in the gold cyanide residues,cyanide must be removed for environmental protection.The process mineralogy of residues was studied firstly,and then cyanide removal was carried out by three chemical methods.The results showed that the residue mainly contained Si,S and Fe.Pyrite was the main metallic mineral,and the iron-complex cyanides make cyanide removal difficult.The minerals in residues were in ultrafine particle size with high monomer dissociation degrees.In H_(2)O_(2)oxidation process,the self-decomposition and side reactions resulted in high consumption of H_(2)O_(2).In Na_(2)S_(2)O_(5)-air oxidation process,the time for complete process was long because of the reactions between Na_(2)S_(2)O_(5)and O_(2).Na_(2)SO_(3)oxidation method was found to be a new method for cyanide removal without air inflation device.The cyanide content was reduced to the national standard level in 90 min at pH 9.0 with optimum Na_(2)SO_(3)dose of 2.0 g/L.展开更多
基金Supported by Scientific Research Project of Hunan Provincial Department of Education(22C0083)。
文摘[Objectives] This study was conducted to solve the prominent problems in the treatment of domestic sewage in southern rural areas of China. [Methods] An integrated process treatment mode of anaerobic/anoxic/aerobic moving bed biofilm reactor (A 2O-MBBR) was proposed to analyze and study its operating effect and influencing factors. [Results] The A^(2)O-MBBR mode had good COD removal efficiency and nitrogen and phosphorus removal performance, and the water quality index of the effluent met the Class A standard of GB181918-2002. This mode is suitable for treating rural domestic sewage, and has high treatment effects in different operating periods. In spring, the average removal rates of COD, NH_(4)^(+)-N, TN, TP and SS reached (83.53 ± 2.15)%, (89.44 ± 4.97)%, (67.36±18.53)%, (88.22±11.21)% and (91.73±2.25)%, respectively;In the autumn period, the average removal rates of COD, NH_(4)^(+)-N, TN, TP and SS were (83.49±2.64)%, (89.26±9.19)%, (66.05±17.00)%, (87.48±9.68)%, and (91.13±2.35)%. [Conclusions] This study provides theoretical reference and technical support for the popularization and application of A^(2)O-MBBR integrated process.
基金Supported by Key Fields of Universities in Guangdong Province (Science and Technology Service for Rural Revitalization)(2021ZDZX4023)2021 Undergraduate Teaching Quality and Teaching Construction Project of Guangdong Province (Guangdong Education Gao Han [2021] 29)+1 种基金Zhaoqing University Quality Engineering and Teaching Reform Project (zlgc 201931)Zhaoqing University Students’Innovation and Entrepreneurship Training Program in 2022 (X 202210580130)。
文摘In recent years, the beer industry is a biological food industry that consumes a lot of water, and it has developed rapidly in China. The sewage discharged from the mass production of beer poses a huge threat to the environment. In order to evaluate and better solve the possible environmental impacts of beer treatment engineering projects, a brewery project in Foshan City is taken as an example to investigate the water pollution generation links of the engineering process including surface water and groundwater. According to the relevant technical methods and standards, water pollution factors are screened, and concentration and discharge are monitored. Through comprehensive analysis, predictive evaluation is obtained. It is confirmed that the project meets the requirements of national laws and regulations and environmental protection standards.
基金Project (2009ZX07315-002-01) supported by Water Pollution Control and Management of Major Special Science and Technology
文摘Full scale experimental study on nitrogen removal for low-carbon wastewater was conducted in reversed A2/O process in Jiguanshi waste water treatment plant in Chongqing,in order to aid the operation and maintenance of similar WWTP. When the proposed measures,such as using 0.1% (volume fraction of wastewater) landfill leachate,shortening HRT by 2/3 in the primary sedimentation tank and controlling DO at 0.5 mg/L in the 3rd section of aerobic zone,are applied,15% of the carbon source can be complemented,the favorable property of activated sludge is achieved,and the nitrogen removal effect is significantly improved. The effluent NH3-N is 2 mg/L and the removal rate is 90%. The effluent TN is 17 mg/L and the removal rate is 54%. The up-to-standard discharge of the effluent is achieved. And after the optimization,the unit electricity consumption also reaches 0.21 kW/h and saves 20%.
基金the financial supports from the National Natural Science Foundation of China(No.51904052)the Chongqing Research Program of Basic Research and Frontier Technology,China(No.cstc2020jcyjmsxm X0476)+1 种基金the Science and Technology Research Program of Chongqing Municipal Education Commission,China(No.KJQN201901508)the Graduate Science and Technology Innovation Training Program of Chongqing University of Science and Technology,China(No.YKJCX2020201)。
文摘Thermodynamic diagrams of Na−S−Fe−H_(2)O system were constructed to analyze the behavior of sulfur and iron in the Bayer process.After digestion,iron mainly exists as Fe_(3)O_(4) and Fe_(2)O_(3) in red mud,and partial iron transfers into solution as Fe(OH)_(3)^(−),HFeO_(2)^(−),Fe(OH)_(4)^(−)and Fe(OH)_(4)^(2−).The dominant species of sulfur is S^(2−),followed by SO_(4)^(2−),and then SO_(3)^(2−)and S_(2)O_(3)^(2−).The thermodynamic analysis is consistent with the iron and sulfur species distribution in the solution obtained by experiments.When the temperature decreases,sulfur and iron can combine and precipitate.Controlling low potential and reducing temperature are beneficial to removing them from the solution.XRD patterns show that NaFeS_(2)·2H_(2)O,FeS and FeS_(2) widely appear in red mud and precipitates of pyrite and high-sulfur bauxite digestion solution.Thermodynamic analysis can be utilized to guide the simultaneous removal of sulfur and iron in the Bayer process.
文摘A bench-scale anaerobic/anoxic/aerobic process-biological aerated filter （A^2/O-BAF） combined system was carded out to treat wastewater with lower C/N and C/P ratios. The A^2/O process was operated in a short aerobic sludge retention time （SRT） for organic pollutants and phosphorus removal, and denitrification. The subsequent BAF process was mainly used for nitrification. The BAF effluent was partially returned to anoxic zone of the A^2/O process to provide electron acceptors for denitrification and anoxic P uptake. This unique system formed an environment for reproducing the denitdfying phosphate-accumulating organisms （DPAOs）. The ratio of DPAOs to phosphorus accumulating organisms （PAOs） could be maintained at 28% by optimizing the organic loads in the anaerobic zone and the nitrate loads into the anoxic zone in the A^2/O process. The aerobic phosphorus over-uptake and discharge of excess activated sludge was the main mechanism of phosphorus removal in the combined system. The aerobic SRT of the A^2/O process should meet the demands for the development of aerobic PAOs and the restraint on the nitrifiers growth, and the contact time in the aerobic zone of the A^2/O process should be longer than 30 min, which ensured efficient phosphorus removal in the combined system. The adequate BAF effluent return rates should be controlled with 1--4 mg/L nitrate nitrogen in the anoxic zone effluent of A^2/O process to achieve the optimal nitrogen and phosphorus removal efficiencies.
基金Supported by Key Technology Research and Development Program of the Tenthfive-year plan (2001BA610A-09), the NationalNatural Science Foundation of China (No. 50478040) and 863 Hi-Technology Research and Development Program of China(No.2004AA601020)
文摘A lab-scale anaerobic-anoxic-oxic (A2O) process used to treat a synthetic brewage wastewater was investigated. The objectives of the study were to identify the existence of denitrifying phosphorus removing bacteria (DPB), evaluate the contribution of DPB to biological nutrient removal and enhance the denitrifying phosphorus removal in A2O bioreactors. Sludge analysis confirmed that the average anoxic P uptake accounted for approximately 70% the total amount of P uptake, and the ratio of anoxic P uptake rate to aerobic P uptake rate was 69%. In addition, nitrate concentration in the anoxic phase and different organic substrate introduced into the anaerobic phase had significant effect on the anoxic P uptake. Compared with conventional A2O processes, good removal efficiencies of COD, phosphorus, ammonia and total nitrogen (92.3%, 95.5%, 96% and 79.5%, respectively) could be achieved in the anoxic P uptake system, and aeration energy consumption was saved 25%. By controlling the nitrate recirculation flow in the anoxic zone, anoxic P uptake could be enhanced, which solved the competition for organic substrates among poly-P organisms and denitrifiers successfully under the COD limiting conditions. Therefore, in wastewater treatment plants the control system should be applied according to the practical situation to optimize the operation.
基金financially supported by the National Key R&D Program of China(No.2018YFC1902002)the Special Fund for the National Natural Science Foundation of China(No.U1608254)。
文摘Because of the highly toxic cyanide in the gold cyanide residues,cyanide must be removed for environmental protection.The process mineralogy of residues was studied firstly,and then cyanide removal was carried out by three chemical methods.The results showed that the residue mainly contained Si,S and Fe.Pyrite was the main metallic mineral,and the iron-complex cyanides make cyanide removal difficult.The minerals in residues were in ultrafine particle size with high monomer dissociation degrees.In H_(2)O_(2)oxidation process,the self-decomposition and side reactions resulted in high consumption of H_(2)O_(2).In Na_(2)S_(2)O_(5)-air oxidation process,the time for complete process was long because of the reactions between Na_(2)S_(2)O_(5)and O_(2).Na_(2)SO_(3)oxidation method was found to be a new method for cyanide removal without air inflation device.The cyanide content was reduced to the national standard level in 90 min at pH 9.0 with optimum Na_(2)SO_(3)dose of 2.0 g/L.
