title: Nitrogen and phosphorus removal in a denitrifying phosphorus removal process in a sequencing batch reactor with a forced anoxic phase.
abstract: The objective of this study was to establish such operating conditions in a sequencing batch reactor (SBR) that will enable the achievement of the highest possible share of denitrifying P removal in nutrient elimination. Two different operating strategies for SBRs were analysed. Both of these strategies used a forced anoxic phase in the SBR treatment cycle. The first one was based on an intermittent aeration, which led to periodic occurrence of anoxic conditions when the uptake of P-PO4(3-) could occur. The second strategy was based on mimicking the A2O process and forcing an anoxic phase straight after an anaerobic phase. The experiments were performed in a laboratory reactor operating at a maximum fill of 26.8-27.7 litres and a constant temperature of 18 degrees C. It was found that a SBR configuration with intermittent aeration did not allow the achievement of significant denitrifying P removal, despite the DPAO/PAO ratio being equal to 50.5%. Almost the entire load of orthophosphates was being removed in aerobic conditions right after the anaerobic phase, even though this aerobic period lasted only 20 minutes. However, a SBR with a forced anoxic phase occurring after an anaerobic phase and created by an introduction of NO(x) rich stream of wastewater guaranteed the highest DPAO/PAO ratio of 82.8% and the highest share of denitrifying P removal (above 80%) in the total removal of phosphorus.
authors.affiliation: Faculty of Environmental Engineering, Warsaw University of Technology, Warsaw, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Podedworna
authors.forename: M
authors.initials: M
authors.lastname: Zubrowska-Sudoł
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors; D009584:Nitrogen / Q000302:isolation & purification*; D010758:Phosphorus / Q000302:isolation & purification*; D018505:Waste Management / Q000379:methods*
chemical_list: D010758:Phosphorus; D009584:Nitrogen