title: Study on decaying characteristics of activated sludge from a circular plug-flow reactor using response surface methodology.
abstract: Using pH values, temperature, and dissolved oxygen as the influencing factors, a decaying characteristics experiment of activated sludge was carried out by combining the LIVE/DEAD® Baclight technique with the 2,3,5-triphenyl tetrazolium chloride - dehydrogenase activity determination method. Using batch experiments, a response surface methodology was applied in the experimental design to determine the most important influential factor in the decay of activated sludge. The activated sludge mixed liquor for the experiment was generated in a laboratory-scale circular plug-flow reactor, which has already been approved for an invention patent. The analyzed results revealed that the most important influential factor in sludge activity decay is the pH, followed by temperature and then dissolved oxygen. After the decay experiment, 40.94-90.03% of sludge activity decay is caused by reduced cell activity, and the rest is due to cell death.
authors.affiliation: College of Water Sciences, Beijing Normal University, Beijing 100875, China.
authors.forename: En
authors.initials: E
authors.lastname: Xie
authors.affiliation: College of Water Sciences, Beijing Normal University, Beijing 100875, China.
authors.forename: Aizhong
authors.initials: A
authors.lastname: Ding
authors.affiliation: College of Water Sciences, Beijing Normal University, Beijing 100875, China.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Dou
authors.affiliation: College of Water Sciences, Beijing Normal University, Beijing 100875, China. Electronic address: zhengleilei@bnu.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Shanghai SEP Analytical Services Co., Ltd., Shanghai 200335, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Yang
mesh_terms: D018533:Biomass; D019149:Bioreactors; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D015233:Models, Statistical; D010100:Oxygen / Q000032:analysis; D012722:Sewage / Q000382:microbiology*; D013778:Tetrazolium Salts; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
chemical_list: D012722:Sewage; D013778:Tetrazolium Salts; C009591:triphenyltetrazolium; D010100:Oxygen
keywords: Decaying characteristics; Dissolved oxygen; Response surface methodology; Temperature; pH