title: Investigation of the effect of free ammonia concentration upon leachate treatment by shortcut biological nitrogen removal process.
abstract: A shortcut biological nitrogen removal (SBNR) process was operated to treat an ammonium rich landfill leachate using a pilot-scale reactor. The SBNR process was intended to oxidize ammonia to nitrite and, then, to reduce it to nitrogen gas. When the hydraulic retention time was 4-3 days, a half of the ammonium oxidized was accumulated as nitrite in the oxidation tank. The nitrite was denitrified completely in the anoxic tank when recycled. The average free ammonia (FA) concentration in the ammonium oxidation tank was 3.7 mg/L. The specific substrate utilization rates of ammonium oxidizers and nitrite oxidizers were investigated at varying FA concentrations through batch experiments. The highest specific ammonium oxidation rate was observed when the FA concentration was 10 mg/L. The rate decreased slightly when the FA concentration was increased to 20 or 50 mg/L, or decreased significantly when it was 5 mg/L. In case of nitrite oxidation, the specific nitrite utilization rate decreased significantly with increasing FA concentration up to 10 mg/L. Consequently, the optimal FA concentration in leachate treatment was 10 mg/L for maximum nitrite accumulation and maximum ammonium removal, or 5 mg/L for lower ammonium concentration and reasonable nitrite accumulation.
authors.affiliation: Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, USA.
authors.forename: Jinwook
authors.initials: J
authors.lastname: Chung
authors.forename: Wookeun
authors.initials: W
authors.lastname: Bae
authors.forename: Yong-Woo
authors.initials: YW
authors.lastname: Lee
authors.forename: Gwang-Beom
authors.initials: GB
authors.lastname: Ko
authors.forename: Sang-Uk
authors.initials: SU
authors.lastname: Lee
authors.forename: Seong-Jun
authors.initials: SJ
authors.lastname: Park
mesh_terms: D019149:Bioreactors; D007700:Kinetics; D009584:Nitrogen / Q000302:isolation & purification* / Q000378:metabolism*; D010084:Oxidation-Reduction; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012037:Refuse Disposal / Q000379:methods*; D012989:Soil Pollutants; D012995:Solubility; D014876:Water Pollution
chemical_list: D000644:Quaternary Ammonium Compounds; D012989:Soil Pollutants; D009584:Nitrogen