Simultaneous P and N removal in a sequencing batch biofilm reactor: insights from reactor- and microscale investigations

• Published in: Water research (Oxford) Vol. 36; no. 2; pp. 501 - 509
• Main Authors: Gieseke, A., Arnz, P., Amann, R., Schramm, A.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 2002
• Subjects: Bacteria; Biofilm; Biofilms; Bioreactors; DNA, Bacterial; Enhanced biological phosphorus removal; Equipment Design; Fluorescence in situ hybridisation; In Situ Hybridization, Fluorescence; Microsensors; Nitrification; Nitrogen - metabolism; Oxygen - metabolism; Oxygen budget; Phosphorus - metabolism; Quaternary Ammonium Compounds - analysis; Quaternary Ammonium Compounds - metabolism; Sequencing batch biofilm reactor; Water Purification - methods; Fluorescence in situ hybridisation; Nitrification; Biofilm; Enhanced biological phosphorus removal; Oxygen budget; Microsensors; Sequencing batch biofilm reactor
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/S0043-1354(01)00232-9

A sequencing batch biofilm reactor (SBBR) with well established enhanced biological phosphate removal (EBPR) was subjected to higher ammonium concentrations to stimulate and eventually implement simultaneous nitrification. Changes of activity and populations were investigated by a combination of online monitoring, microsensor measurements and fluorescence in situ hybridisation (FISH) of biofilm sections. Nitrification and nitrifying bacteria were always restricted to the periodically oxic biofilm surface. Both, activity and population size increased significantly with higher ammonium concentrations. Nitrification always showed a delay after the onset of aeration, most likely due to competition for oxygen by coexisting P accumulating and other heterotrophic bacteria during the initial aeration phase. This view is also supported by comparing oxygen penetration and oxygen uptake rates under low and high ammonium conditions. Therefore, simultaneous nitrification and phosphorus removal in a P removing SBBR appears to be only possible with a sufficiently long oxic period to ensure oxygen availability for nitrifiers.