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 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.
