Enhancement of nitrogen and phosphorus removal, sludge reduction and microbial community structure in an anaerobic/anoxic/oxic process coupled with composite ferrate solution disintegration

Waste activated sludge (WAS) was disintegrated by composite ferrate solution (CFS) in this work, and the effect of CFS disintegrated sludge supernatant (CDSS), as a supplementary carbon source, on enhancement of nitrogen and phosphorus removal and sludge reduction in an AAO-CFSSDR (Anaerobic/Anoxic/Oxic combined with CFS-Sludge disintegration reactor) process was evaluated. The results showed that CDSS was easily utilizable by the denitrification bacteria due to the high content of readily biodegradable substrates. When compared with the AAO process, the operation results of AAO-CFSSDR suggested that the removal efficiencies of TN, NH4+-N and TP increased from 71.15, 79.23 and 85.52% to 85.05, 87.70 and 90.06%, respectively; and the sludge was reduced by 34.79%. The 16SrRNA high-throughput sequencing results showed that the introduction of CDSS weakened the microbial diversity but enhanced the microbial richness; and the abundance of bacteria related to the removal of nitrogen and phosphorus, increased in the AAO-CFSSDR process. •CDSS was easily utilized by the denitrification bacteria for the high content of Ss.•AAO-CFSSDR process can enhance N and P removal and sludge reduction.•CDSS weakened the microbial diversity but enhanced the microbial richness.•Bacteria related to the removal of N and P increased in the AAO-CFSSDR.