This research identified suitable conditions for long-term inhibition of nitrite-oxidizer bacteria (NOB) in a sequencing batch reactor for the treatment of centrate by over-nitrite pathways. The NOB were inhibited by free ammonia concentrations greater than 20 mg NH3-N/L
combined with a dissolved oxygen concentration less than 0.3 mg O2/L and a temperature of 30°C. The experiments were performed in a laboratory-scale 2.5-L reactor fed with synthetic and actual centrate from a full-scale wastewater treatment plant (800 to 1500 mg NH4+-N/L).
The influence of influent-alkalinity-to-ammonium ratio (AAR) on the effluent-nitrite-to-ammonium ratio (NAR) also was investigated. The control of the effluent NAR was possible by adjusting the influent AAR when NOB inhibition was maintained and when total alkalinity depletion took place before
the end of the cycle. The maximum nitritation rate of 860 mg NO2−-N oxidized/L·d was obtained when the influent NH4+-N concentration was 800 mg NH4+-N/L and the hydraulic retention time was 1.7 days.
Water Environment Research® (WER®) publishes peer-reviewed research papers, research notes, state-of-the-art and critical reviews on original, fundamental and applied research in all scientific and technical areas related to water quality, pollution control, and management. An annual Literature Review provides a review of published books and articles on water quality topics from the previous year. Published as: Sewage Works Journal, 1928 - 1949; Sewage and Industrial Wastes, 1950 - 1959; Journal Water Pollution Control Federation, 1959 - Oct 1989; Research Journal Water Pollution Control Federation, Nov 1989 - 1991; Water Environment Research, 1992 - present.