title: Feasibility of biological aerated filters (BAFs) for treating landfill leachate.
abstract: Ammonia can be removed from landfill leachate using aerobic biological treatment processes. The biological aerated filter (BAF) combines biological treatment and subsequent biomass separation in one reactor providing a small footprint alternative to conventional systems. Leachate from an operational landfill was found to be aerobically treatable using the OECD recommended Modified Zahn-Wellens test. This leachate was used as feed to a pilot-scale BAF at influent chemical oxygen demand (COD) and ammoniacal-nitrogen concentrations of 765 mg l(-1) and 568 mg l(-1) respectively. During an initial period of stable operation without pH control, 33 %w/w of influent ammonia was removed. The reactor pH was 9.2 with little conversion to total oxidized nitrogen (< 45 mg l(-1)), this removal was accounted for primarily by air stripping. In a second period of stable operation, the reactor pH was reduced to pH 7.2 and ammonia removal increased to 97 %w/w with a concomitant increase in effluent nitrite concentration to an average of 524 mg l(-1). Biological aerated filters (BAFs) can be used to nitrify landfill leachates though onward denitrification of nitrite-nitrogen and COD polishing is required to reach typical discharge consent standards.
authors.affiliation: School of Water Sciences, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK.
authors.forename: T
authors.initials: T
authors.lastname: Stephenson
authors.forename: S J T
authors.initials: SJ
authors.lastname: Pollard
authors.forename: E
authors.initials: E
authors.lastname: Cartmell
mesh_terms: D000641:Ammonia / Q000032:analysis* / Q000302:isolation & purification; D001420:Bacteria, Aerobic; D005240:Feasibility Studies; D005374:Filtration / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009566:Nitrates / Q000032:analysis; D009573:Nitrites / Q000032:analysis; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis; D010865:Pilot Projects; D012037:Refuse Disposal / Q000295:instrumentation / Q000379:methods*; D012722:Sewage
chemical_list: D009566:Nitrates; D009573:Nitrites; D012722:Sewage; D000641:Ammonia; D010100:Oxygen