title: N-removal performance and underlying bacterial taxa of upflow filter bioreactor system under different dissolved oxygen and internal recycle conditions.
abstract: Biological N-removal treatment of piggery wastewater in the upflow anaerobic-anoxic-aerobic floating filter (UA(3)FF) bioreactor based on the concept of nitritation-denitritation was studied along with the changes in internal recycle ratio and dissolved oxygen concentration (DO). Consecutive changes in the recirculation ratio between the anoxic and aerobic reactors has resulted in abundance and composition shifts of N-cycling bacteria as well as other bacterial groups, reflecting different survival strategies across (bio/physico)chemical milieu. The DO concentration was optimized to achieve nitritation in the aerobic reactor and denitritation in the anoxic reactor. Optimal nitritation-denitritation (270 and 130 g NO(2) (-)-N produced or reduced/m(3) filter media/day) was obtained at DO of 1.0-1.5 mg/l, inter-reactor recirculation ratio of 1:1-2:1, HRT of 24 h, pH of 7.6 +/- 0.3, and temperature of 28 +/- 4 degrees C. Since only well known nitrifying and denitrifying taxa were found, nitritation-denitritation was likely carried out by these bacteria rather than the yet unidentified novel taxa. Archaeal nitrifiers recently discovered to be important in the global N-cycle were not detected.
authors.affiliation: Environmental Engineering and Management, Asian Institute of Technology, Klong Luang, Pathumthani 12120, Thailand.
authors.forename: Prasert
authors.initials: P
authors.lastname: Laobusnanant
authors.forename: Seung Hwan
authors.initials: SH
authors.lastname: Lee
authors.forename: Alfredo J
authors.initials: AJ
authors.lastname: Anceno
authors.forename: Gopal C
authors.initials: GC
authors.lastname: Ghosh
authors.forename: Dong Jin
authors.initials: DJ
authors.lastname: Kim
authors.forename: Bipin K
authors.initials: BK
authors.lastname: Pathak
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Shipin
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D000818:Animals; D020562:Betaproteobacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001698:Biomedical Engineering; D019149:Bioreactors / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004867:Equipment Design; D017404:In Situ Hybridization, Fluorescence; D017744:Medical Waste Disposal; D009584:Nitrogen / Q000302:isolation & purification* / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D034421:Sus scrofa; D014865:Waste Disposal, Fluid
chemical_list: D004269:DNA, Bacterial; D017744:Medical Waste Disposal; D009584:Nitrogen; D010100:Oxygen