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
Aluminum ions produced by aluminum mining,electrolytic industry and aluminum-based coagulants can enter wastewater treatment plants and interact with activated sludge.They can subsequently contribute to the removal of...Aluminum ions produced by aluminum mining,electrolytic industry and aluminum-based coagulants can enter wastewater treatment plants and interact with activated sludge.They can subsequently contribute to the removal of suspended solids and affect activated sludge flocculation,as well as nitrogen and phosphorus removal.In this study,the effects of Al^3+on pollutant removal,sludge flocculation and the composition and structure of extracellular polymeric substances(EPS)were investigated under anaerobic,anoxic and oxic conditions.Results demonstrated that the highest chemical oxygen demand(COD)and total nitrogen(TN)removal efficiencies were detected for an Al^3+concentration of 10 mg/L.In addition,the maximal dehydrogenase activity and sludge flocculation were also observed at this level of Al^3+.The highest removal efficiency of total phosphorus(TP)was achieved at an Ar+concentration of30 mg/L.The flocculability of sludge in the anoxic zone was consistently higher than that in the anaerobic and oxic zones.The addition of Al^3+promoted the secretion of EPS.Tryptophan-like fluorescence peaks were detected in each EPS layer in the absence of Al^3+.At the Al^3+concentration of 10 mg/L,fulvic acid and tryptophan fluorescence peaks began to appear while the majority of protein species and the highest microbial activity were also detected.Low Al^3+concentrations(<10 mg/L)could promote the removal efficiencies of COD and TN,yet excessive Al^3+levels(>10 mg/L)weakened microbial activity.Higher Al^3+concentrations(>30 mg/L)also inhibited the release of phosphorus in the anaerobic zone by reacting with PO4^3-.展开更多
The aluminum ions generated from mining aluminum,electrolytic aluminum and the industrial production of aluminum-based coagulants(such as AlCl3 and Al2(SO4)3)enter sewage treatment plants and interact with activated s...The aluminum ions generated from mining aluminum,electrolytic aluminum and the industrial production of aluminum-based coagulants(such as AlCl3 and Al2(SO4)3)enter sewage treatment plants and interact with activated sludges.An anaerobic/anoxic/oxic(A2^O)process was used to reveal the effects of Al^3+on the pollutant removal efficiencies,bioflocculation and the micro structure of sludge.The results showed that a low concentration of Al^3+improved the pollutant removal efficiencies and increased the sludge particle size.However,a high concentration of Al^3+hindered microbial flocculation and reduced the pollutant removal efficiencies.With a 10 mg/L Al^3+addition,the chemical oxygen demand(COD),total nitrogen(TN)and NH4+-N increased by 3%,16%and 27%,and reached as high as 68%,60%and 87%,respectively.At the same time,the dehydrogenase activity,flocculation ability(FA)and contact angle of the sludge reached their maximum levels at 41.3 mg/L/hr,45%and 79.63°,respectively.The specific surface area of the sludge decreased to 7.084 m2/g and the sludge pore size distribution shifted to concentrate in the me soporous range.Most of Al^3+was adsorbed on the surface of sludge,changing the physicochemical properties and physical structure of the sludge.展开更多
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This research was financially supported by the National Natural Science Foundation of China(Grant Nos.51678119 and 51808254)the Science and Technology Development Program of Jilin Province(Nos.20180201016SF and 20180101079JC)the Scientific Research Foundation from Education Department of Jilin Province(Nos.JJKH20180453KJ and JJKH20180454KJ).
文摘Aluminum ions produced by aluminum mining,electrolytic industry and aluminum-based coagulants can enter wastewater treatment plants and interact with activated sludge.They can subsequently contribute to the removal of suspended solids and affect activated sludge flocculation,as well as nitrogen and phosphorus removal.In this study,the effects of Al^3+on pollutant removal,sludge flocculation and the composition and structure of extracellular polymeric substances(EPS)were investigated under anaerobic,anoxic and oxic conditions.Results demonstrated that the highest chemical oxygen demand(COD)and total nitrogen(TN)removal efficiencies were detected for an Al^3+concentration of 10 mg/L.In addition,the maximal dehydrogenase activity and sludge flocculation were also observed at this level of Al^3+.The highest removal efficiency of total phosphorus(TP)was achieved at an Ar+concentration of30 mg/L.The flocculability of sludge in the anoxic zone was consistently higher than that in the anaerobic and oxic zones.The addition of Al^3+promoted the secretion of EPS.Tryptophan-like fluorescence peaks were detected in each EPS layer in the absence of Al^3+.At the Al^3+concentration of 10 mg/L,fulvic acid and tryptophan fluorescence peaks began to appear while the majority of protein species and the highest microbial activity were also detected.Low Al^3+concentrations(<10 mg/L)could promote the removal efficiencies of COD and TN,yet excessive Al^3+levels(>10 mg/L)weakened microbial activity.Higher Al^3+concentrations(>30 mg/L)also inhibited the release of phosphorus in the anaerobic zone by reacting with PO4^3-.
基金supported by the National Natural Science Foundation of China(Nos.51678119 and 51808254)the Department of Science and Technology of Jilin Province(Nos.20180201016SF and 20180101079JC)
文摘The aluminum ions generated from mining aluminum,electrolytic aluminum and the industrial production of aluminum-based coagulants(such as AlCl3 and Al2(SO4)3)enter sewage treatment plants and interact with activated sludges.An anaerobic/anoxic/oxic(A2^O)process was used to reveal the effects of Al^3+on the pollutant removal efficiencies,bioflocculation and the micro structure of sludge.The results showed that a low concentration of Al^3+improved the pollutant removal efficiencies and increased the sludge particle size.However,a high concentration of Al^3+hindered microbial flocculation and reduced the pollutant removal efficiencies.With a 10 mg/L Al^3+addition,the chemical oxygen demand(COD),total nitrogen(TN)and NH4+-N increased by 3%,16%and 27%,and reached as high as 68%,60%and 87%,respectively.At the same time,the dehydrogenase activity,flocculation ability(FA)and contact angle of the sludge reached their maximum levels at 41.3 mg/L/hr,45%and 79.63°,respectively.The specific surface area of the sludge decreased to 7.084 m2/g and the sludge pore size distribution shifted to concentrate in the me soporous range.Most of Al^3+was adsorbed on the surface of sludge,changing the physicochemical properties and physical structure of the sludge.
