[Effect of Anaerobic Plug-flow on Nitrification Denitrifying Phosphorus Removal Aerobic Granular Sludge with Intermittent Aeration].

Actual domestic sewage has a complex composition and relatively low carbon and nitrogen content. Anaerobic plug-flow influent can enhance the utilization of COD by aerobic granular sludge by providing a locally high concentration of substrate. In this study, intermittent aeration was used to cultivate aerobic granular sludge in a sequencing batch reactor (SBR), and actual domestic sewage was used as the feed water to inoculate the sewage plant sludge. In the R1 experiment, rapid anaerobic feeding was adopted, while in R2, anaerobic plug-flow feeding was adopted, to explore the impact of different feeding modes on the aerobic granular sludge system of domestic sewage. Under rapid anaerobic feeding in R1, the particle structure appeared earlier, but particle breakage occurred after 71 days of operation; the particle structure generated in R2 was denser than that of R1, the particle surfaces were smoother, and the denitrifying phosphorous accumulating organisms (DPAO) had a more enriching effect. In the final R1 and R2 reactors, the proportion of DPAO to phosphorous accumulating organisms (PAO) was 14.17% and 22.07%, respectively. The results show that the anaerobic plug-flow feeding mode can enhance the use of influent COD by granular sludge, which is conducive to enriching DPAO, generating denser and more stable particles, realizing "one carbon dual purpose" operation, and removing more nitrogen and phosphorus.