Enrichment culture of denitrifying phosphorus removal sludge and its microbial community analysis

An efficient one-step domestication method with mixed electron acceptors and short-time post-aeration was developed for the enrichment culture of denitrifying phosphorus removal sludge. The acclimation time, performance of nitrogen and phosphorus simultaneous removal and microbial community structure were investigated to reveal the difference among the obtained phosphorus removal sludge using different acclimation ways. Results showed that the proposed method with optimal proportion of nitrite and nitrate could significantly shorten domestication time (28 days) compared with the traditional two-step method (60 days), but exerted nearly no influence on the removal efficiency of nitrogen and phosphorus. High-throughput sequencing revealed that similar microbial community structure of DPAOs sludge was obtained with different acclimation methods. Compared with seed sludge, microbial community shifted obviously, and the dominant microbial population of Dechloromonas-related phosphorus removal bacteria increased significantly. It could be inferred that the appropriate concentration of nitrite was conducive to the rapid enrichment of DPAOs under alternative anaerobic/anoxic operation. Meanwhile, anaerobic/oxic condition was favorable for the enrichment of Candidatus Accumulibacter-related phosphorus removal organisms, and short-time post-aeration in the proposed method could reduce the potential public health hazard.