title: Enhanced biological nitrogen removal in MLE combined with post-denitrification process and EF clarifier.
abstract: A modified ludzack ettinger reactor (MLE) combined with a post-denitrification reactor (PDMLE) using electroflotation (EF) as a secondary clarifier was investigated on its feasibility and process performance. Results indicated that higher mixed liquor suspended solids (MLSS) concentrations in bioreactor (5,350 ± 352 mg L(-1)) were maintained via the highly concentrated return sludge (16,771 ± 991 mg L(-1)) from the EF clarifier and the effluent suspended solids (SS) concentrations continued relatively low, representing effluent SS concentration of 1.71 ± 1.16 mg L(-1), compared with GS-A2O process during the operation of four months. The denitrification was improved by combining MLE process with post-denitrification based on endogenous decay (i.e. no additional carbon source was added), resulting in the removal efficiencies of TN were about 91 and 59% for the influent C/N ratio of 10 and 5, respectively, revealing relatively high nitrogen removal as compared with EF-A2O and gravity settling (GS)-A2O processes as a control. The nitrogen balance analysis indicates that pre-denitrification and post-denitrification contributed to 78 and 22% of TN removed, respectively.
authors.affiliation: Department of Urban Engineering, The University of Tokyo, Tokyo, Japan.
authors.forename: C M
authors.initials: CM
authors.lastname: Chung
authors.forename: K W
authors.initials: KW
authors.lastname: Cho
authors.forename: Y J
authors.initials: YJ
authors.lastname: Kim
authors.forename: K
authors.initials: K
authors.lastname: Yamamoto
authors.forename: T H
authors.initials: TH
authors.lastname: Chung
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D004563:Electrochemistry / Q000379:methods*; D009584:Nitrogen / Q000302:isolation & purification / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
chemical_list: D012722:Sewage; D014874:Water Pollutants, Chemical; D009584:Nitrogen