Alleviation of substrate inhibition in an anaerobic ammonia oxidation reactor: Recovery process performance and microbial community

Abstract

Substrate inhibition is one of the key factors that threatens the stability of anaerobic ammonia oxidation (anammox) reactors. Most of the current studies have focused on the inhibition of anammox by substrates; however, little attention has been given to the recovery process and microbial community changes in anammox reactors after inhibition. To remediate the damage substrate inhibition can do to anammox systems, the study investigated the recovery process of an anammox reactor that was inhibited by high substrate concentrations. The results showed that a reduction in the ratio of influent NO2−-N to NH4+-N from the theoretical stoichiometric ratio of 1.32 to 0.5 was conducive to the rapid recovery of anammox system performance. The analysis of the microbial community structure indicated that the relative abundance of the primary anammox bacteria on the biofilm carriers and mixed sludge was 19.51 % and 9.92 %, respectively, after reactor recovery. Biofilms played an important role in resisting reactor destabilization.