A novel strategy for simultaneous removal of nitrogen and organic matter using anaerobic granular sludge in anammox hybrid reactor.

The coexistence of organic matter (OM) and nitrogen in industrial effluent is the major bottleneck in field-scale application of anammox process. The present study emphasized on investigating the role of seeding anaerobic granular sludge towards simultaneous removal of ammonium and OM in anammox hybrid reactor (AHR). The study delineated simultaneous reduction of both OM (94.8%) and nitrogen (96.8%) at optimal COD/N ratio (0.54). Pearson correlation matrix showed positive and strong correlation of ARE (ammonium removal efficiency) and CRE (COD removal efficiency) with NRE (nitrogen removal efficiency). The negative correlation of OLR and COD/TN ratio with NRE indicated that increase in organic loadings may suppress anammox activity. The process inhibition was evaluated using Haldane model considering free ammonia, OM and nitrite as inhibitors. The strategy of using anaerobic granular sludge not only augmented endurance of bacterial communities against OM inhibition but also facilitated simultaneous removal of OM and nitrogen.