Tertiary nitrification in pure oxygen moving bed biofilm reactors

Abstract

Two bench-scale reactors, fed with the secondary effluent of a municipal wastewater treatment plant (WWTP), were used in order to study tertiary nitrification in pure oxygen moving bed biofilm reactors (PO-MBBRs) with patented KMT® media as biofilm carriers. The process allowed to measure very high nitrification rates, both in ammonia limiting conditions (up to 7 gN m−2 d−1; oxygen-to-ammonia nitrogen ratio higher than 3–4 mgO2 (mgN)−1) and in oxygen limiting conditions (up to 8 gN m−2 d−1; oxygen-to-ammonia nitrogen ratio lower than 1–2 mgO2 (mgN)−1). Since the process proved flexible and reliable, it is suitable for full-scale application to municipal WWTPs. Typical application could regard, but is not limited to, tertiary nitrification of secondary effluent from existing high-purity oxygen activated sludge systems designed to achieve only organic carbon removal.