Comparison of operating performance and microbial characteristics achieving mainstream Anammox between continuous low-oxygen aeration and intermittent aeration modes
Operating performance of mainstream anaerobic ammonia oxidation(Anammox)for treating simulated municipal wastewater was compared respectively under two modes of continuous low-oxygen aeration and intermittent aeration.Intermittent aeration achieved mainstream Anammox in a shorter period with only 24d.The ammonia removal efficiency(ARE)was(96.0±1.0)%and the total nitrogen removal efficiency(TNRE)was(80.2±2.0)%under intermittent aeration.Compared with continuous aeration,nitrogen removal efficiency was more stable and nitrogen removal loading rate was higher.Intermittent aeration elevated both aerobic and anaerobic anammox activities,promoting extracellular polymeric substance(EPS)secretion,increasing protein(PN)content and protein/polysaccharide(PN/PS),which could form a more dense and red anammox biofilm structure.Three-dimensional fluorescence spectra found that the fluorescence intensity of peak A of soluble EPS(S-EPS)increased significantly during intermittent aeration.High-throughput sequencing confirmed that different aeration ways caused significant differences in microbial community composition and quantity of functional genes.Intermittent aeration improved the population structure and increased the relative abundance of aerobic ammonia oxidizers and contributed to the enrichment of Anammox bacteria(Candidatus Brocadia,Candidatus Kuenenia).The gene annotation results indicated synergistic nitrogen removal pathway of partial nitrification/partial denitrification+anammox existed in intermittent aeration condition.
continuous low-oxygen aerationintermittent aerationmainstream anammoxnitrogen removalEPSmicrobial community