[Simultaneous Domestication of Short-cut Nitrification Denitrifying Phosphorus Removal Granules]

In this experiment, three replicated SBR reactors were operated using asynchronous acclimation of the phased method (A/O-A/O/A), simultaneous domestication of continuous aeration by A/O/A, and simultaneous domestication of intermittent aeration by A/O/A. Using artificial water distribution as the influent substrate, flocculent sludge was inoculated and granulated by hydraulic selection. The domestication and nitrogen and phosphorus removal characteristics of shortcut nitrification denitrifying phosphorus removal granules under different operation modes were assessed. The results show that simultaneous domestication of intermittent aeration by A/O/A has the most efficient under the combination of short aeration time (140 min) and low aeration strength[3.5 L·(h·L)^-1]. The average removal rates of carbon, nitrogen, and phosphorus were 90.74%, 91.15%, and 95.66%, respectively, which could achieve synchronous removal during later stable operation. The particle size was 895 μm, and the particles were small but uniformly dense in microscope observations. The f value (MLVSS/MLSS) was kept stable at 0.8-0.85 and sludge had a high biomass due to the alternate aerobic/anoxic operation with intermittent aeration. This supported anoxic heterotrophic bacteria at the core of the particles, which was conducive to the stability of the granular sludge structure. Batch experiments showed that the specific ammonia-oxidation rate of the simultaneous domestication of intermittent aeration by A/O/A system was 3.38 mg·(g·h)^-1, and denitrifying phosphate accumulating organisms (DPAOs) able to utilize nitrite as electron acceptor accounted for 65.46%. This was more conducive to the simultaneous domestication and enrichment of ammonia-oxidizing bacteria (AOB) and NO₂^--type DPAOs, ensuring a stable treatment effect.