关键词: 双污泥系统, 生物膜, 反硝化除磷, 低C/N, 污水, 降解

Abstract:

Anaerobic/anoxic/oxic (AAO)-biological aerated filter (BAF) is a two-sludge system with different SRT, which can remove nitrogen and phosphorus simultaneously in the low C/N condition. The startup of a pilot-scaled AAO-BAF system with capacity of 40—100 m³·d^-1 used for treating real domestic sewage was studied in this experiment. The AAO and BAF run independently in order to cultivate and acclimate the phosphorus accumulating organisms (PAOs) and nitrifying bacterial biofilms, respectively. When the TP concentration of AAO effluent and concentration of BAF effluent were found keeping stable, the two parts were combined. With this operation strategy, the effluent concentration of COD,, TN, TP, NTU and SS was lower than 50 mg·L^-1, 5 mg·L^-1, 15 mg·L^-1, 0.5 mg·L^-1, 5 NTU and 10 mg·L^-1 in the 58th day, respectively, indicating the successful setup of the pilot-scaled process. Comparing with the lab-scale study, the separate running had more advantage in cultivating PAOs. The formation of natural biofilm in BAF was more convenient than the method of inoculated sludge, but needed longer time. According to the analysis of microbial community diversity, the abundance of nitrobacteria was less than 3% in the AAO system, however, it was higher than 12% on the biofilm in BAF. This experiment can provide a reference for practical engineering application of the process.

Key words: two-sludge system, biofilm, denitrifying phosphorus removal, low C/N ratio, waste water, degradation