Nitric oxide for anammox recovery in a nitrite-inhibited deammonification system.

The anaerobic ammonium oxidation (anammox) process is widely used for N-rich wastewater treatment. In the current research the deammonification reactor in a reverse order (first anammox, then the nitrifying biofilm cultivation) was started up with a high maximum N removal rate (1.4 g N m−2 d−1) in a moving bed biofilm reactor. Cultivated biofilm total nitrogen removal rates were accelerated the most by anammox intermediate – nitric oxide (optimum 58 mg NO-N L−1) addition. Furthermore, NO was added in order to eliminate inhibition caused by nitrite concentrations (>50 mg ) increasing (2/1, respectively) along with a higher ratio of (0.6/1, respectively) than stoichiometrical for this optimal NO amount added during batch tests. Planctomycetales clone P4 sequences, which was the closest (98% and 99% similarity, respectively) relative to Candidatus Brocadia fulgida sequences quantities increase to 1 × 106 anammox gene copies g−1 total suspended solids to till day 650 were determined by quantitative polymerase...