Bacterial composition and nutrient removal with a novel PIA-A2/O sewage treatment

A novel post intermittent aeration anaerobic-anoxic-oxic (PIA-A2/O) process was developed to integrate shortcut nitrification-denitrification with denitrifying phosphorus (P) removal for domestic sewage treatment. With the transformation in configuration and phased start-up strategy, the nitritation rate and the ratio of denitrifying phosphorus accumulating organisms to phosphorus accumulating organisms (DPAO/PAO) were enhanced greatly to 88.2% and 83.9-91.7% in the PIA-A2/O process, respectively. Improved total nitrogen and phosphorus removal were achieved at long sludge retention time and low aeration. High sludge activity was maintained through the periodic selection of the additional intermittent aeration zone. High-throughput sequencing revealed that Bacteroidetes (38.96%), Proteobacteria (33.59%), TM7 (4.53%), Chloroflexi (3.09%), and Firmicutes (2.49%) were the dominant phyla in the resultant bacterial community. Abundant anaerobic and facultative bacteria conducive to excess sludge reduction were generated by this process. Potential DPAOs involve the genera of Brevundimonas, Brachymonas, Steroidobacter, Haliscomenobacter, and Rhodocyclus.