title: Net P-removal deterioration in enriched PAO sludge subjected to permanent aerobic conditions.
abstract: Recently, some research in the field of enhanced biological phosphorus removal (EBPR) has been focused on studying systems where the electron donor (substrate) and the electron acceptor (nitrate or oxygen) are present simultaneously. This can occur, for example, in a full scale wastewater treatment plant during heavy rainfall periods when the anaerobic hydraulic retention time is temporarily shortened. To study this situation that could induce EBPR failure, the operation of a sequencing batch reactor (SBR) working under alternating anaerobic-aerobic conditions with an enriched EBPR population (50% Candidatus Accumulibacter phosphatis and less than 1% Candidatus Competibacter phosphatis) was shifted to strict aerobic operation. Seven cycle studies were performed during the 11 days of aerobic operation. Net P-removal was observed in this aerobic SBR during the first 4 days of operation but the system could not achieve net-P removal after this period, although the microbial composition, in terms of percentage of Accumulibacter and Competibacter, did not change significantly. The observed changes in the different compounds analysed (phosphorus, acetate, glycogen and PHB) as well as in the OUR profile indicate that metabolic changes are produced for the adaptation of PAO to aerobic conditions.
authors.affiliation: Departament d'Enginyeria Química, ETSE, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
authors.forename: Maite
authors.initials: M
authors.lastname: Pijuan
authors.forename: Albert
authors.initials: A
authors.lastname: Guisasola
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Baeza
authors.forename: Julián
authors.initials: J
authors.lastname: Carrera
authors.forename: Carles
authors.initials: C
authors.lastname: Casas
authors.forename: Javier
authors.initials: J
authors.lastname: Lafuente
mesh_terms: D001420:Bacteria, Aerobic / Q000378:metabolism*; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology*; D018920:Coculture Techniques / Q000379:methods*; D010100:Oxygen / Q000378:metabolism*; D010758:Phosphorus / Q000302:isolation & purification / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D018508:Water Purification / Q000379:methods
chemical_list: D012722:Sewage; D010758:Phosphorus; D010100:Oxygen