Anoxic phosphorus removal by denitrifying heterotrophic bacteria
Lacko, N.; Drysdale, G.D.; Bux, F.
Water Science and Technology a Journal of the International Association on Water Pollution Research 47(11): 17-22
2003
ISSN/ISBN: 0273-1223 PMID: 12906266 Document Number: 561887
The unexplained occurrence of anoxic phosphorus (P) accumulation has largely hampered modelling of nitrification denitrification biological excess P removal (NDBEPR) systems. This study was conducted to isolate and identify denitrifying-P accumulating heterotrophic bacteria (DPBs) from a NDBEPR system 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 utilizing 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 mg PO4-P/litre removal, respectively, at an initial NO3 concentration of 13.54 mg NO3-N/litre and P concentration of 16.34 mg PO4-P/litre. 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.