title: The selective role of nitrite in the PAO/GAO competition.
abstract: Proliferation of Glycogen Accumulating Organisms (GAOs) accounts as one of the major bottlenecks in biological phosphorus removal systems. GAO outcompeting polyphosphate accumulating organisms (PAOs) results in lower P-removal. Thus, finding optimal conditions that favour PAO in front of GAO is a current focus of research. This work shows how nitrite can provide a novel strategy for PAO enrichment. A propionate-fed GAO-enriched biomass (70% Defluviicoccus I, 18% Defluviicoccus II and 10% PAO) was subjected more than 50 d under anaerobic-anoxic conditions with nitrite as electron acceptor. These operational conditions led to a PAO-enriched sludge (85%) where GAO were washed out of the system (<10%), demonstrating the validity of the new approach for PAO enrichment. In addition, the presented suppression of Defluviicocus GAO with nitrite represents an add-on benefit to the nitrite-based systems since the proliferation of non-desirable GAO can be easily ruled out and added to the other benefits (i.e. lower aeration and COD requirements).
authors.affiliation: Departament d'Enginyeria Química, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain. Electronic address: carlota.taya@uab.cat.
authors.forename: Carlota
authors.initials: C
authors.lastname: Tayà
authors.forename: Vijay Kumar
authors.initials: VK
authors.lastname: Garlapati
authors.forename: Albert
authors.initials: A
authors.lastname: Guisasola
authors.forename: Juan A
authors.initials: JA
authors.lastname: Baeza
mesh_terms: D001673:Biodegradation, Environmental; D058440:Denitrification; D006003:Glycogen / Q000378:metabolism; D056265:Microbial Interactions; D009573:Nitrites / Q000032:analysis / Q000378:metabolism*; D010710:Phosphates / Q000032:analysis / Q000378:metabolism; D010758:Phosphorus / Q000032:analysis / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D009573:Nitrites; D010710:Phosphates; D012722:Sewage; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D006003:Glycogen
keywords: Enhanced biological phosphorus removal (EBPR); Glycogen Accumulating Organisms (GAOs); Nitrite; Polyphosphate accumulating organisms (PAOs); Selection