title: Anoxic phosphorus removal by denitrifying heterotrophic bacteria.
abstract: The unexplained occurrence of anoxic phosphorus (P) accumulation has largely hampered modeling of nitrification denitrification biological excess P removal (NDBEPR) systems. The aim of this study was, therefore, to isolate and identify denitrifying-P accumulating heterotrophic bacteria (DPBs) from a NDBEPR system in order to evaluate anoxic P accumulation and the specific mechanisms involved. Results of the study showed various heterotrophic bacteria to be capable of anoxic P accumulation utilising nitrate (NO3) as electron acceptor. While Pseudomonas spp. predominated, Serratia spp. and Vibrio spp. demonstrated the most efficient anoxic P accumulation with 7.10 and 7.29 mgPO4-P/L removal, respectively, at an initial NO3 concentration of 13.54 mgNO3-N/L and P concentration of 16.34 mgPO4-P/L. Weaker DPBs were also identified which were only capable of accumulating small amounts of P at low initial P and NO3 concentrations due to weak denitrification capacity. Anoxic P release was also observed due to the presence of acetate.
authors.affiliation: Centre for Water and Wastewater Research, Technikon Natal, P O Box 953, Durban 4000, South Africa.
authors.forename: N
authors.initials: N
authors.lastname: Lacko
authors.forename: G D
authors.initials: GD
authors.lastname: Drysdale
authors.forename: F
authors.initials: F
authors.lastname: Bux
mesh_terms: D010100:Oxygen; D010758:Phosphorus / Q000302:isolation & purification* / Q000378:metabolism*; D011549:Pseudomonas / Q000502:physiology; D012705:Serratia / Q000502:physiology; D014733:Vibrio / Q000502:physiology; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
chemical_list: D010758:Phosphorus; D010100:Oxygen