Nitrogen removal improvement by denitrifying ammonium oxidation in anoxic/oxic-sequence batch biofilm reactor system

Denitrifying ammonium oxidation (DEAMOX) technology was applied to improve nitrogen removal from real low-carbon/nitrogen domestic wastewater in an anoxic/oxic sequencing batch biofilm reactor (A/O-SBBR) system. The system consisted of an anoxic SBBR (An-SBBR) and an oxic nitrification SBBR (N-SBBR). The system was operated in A/O mode for 240 days and anaerobic ammonium oxidation (anammox) bacteria were added into An-SBBR on day 160. Excellent nitrification performance was achieved in the N-SBBR with the NH4+-N removal efficiency of 98.01%, and nitrifiers were enriched with a proportion of 3.44%. DEAMOX was achieved in the An-SBBR with nitrite accumulation and ammonia loss. After adding anammox bacteria, the total inorganic nitrogen removal efficiency improved from 50.78% to 72.30%. Thauera and candidatus_Brocadia were detected with the proportions of 13.75% and 0.53%, respectively, which were strongly related to partial denitrification and anammox.