好氧颗粒污泥处理市政污水性能与微生物特性研究

With the mature aerobic granular sludge (AGS) as seed sludge, the treatment efficiency, sludge characteristics and microbial diversity were investigated when treating actual municipal wastewater in sequencing batch reactor (SBR). The results showed that the effluent COD concentration was lower than 50 mg•L^-1 and the effluent NH₄⁺-N concentration stabilized at 0.7~0.8 mg•L^-1 under the condition of low organic loading rate(intake COD about 179~212 mg•L^-1) and high dissolved oxygen (DO>5 mg•L^-1). However, the nitrogen and phosphorus removal efficiency needed to be optimized. The granular sludge with size of 0.2~0.6 mm revealed strong stability in the system. And The sludge showed good settleability with the sludge volumetric index (SVI₃₀) of 32~40 mL•g^-1 during the operation. The results also proved thatthe existence of small amounts of flocculent sludge seemed to be beneficial to the AGS stability. Under the experimental conditions, the system performed well and stably with 30% sludge with the size of less than 0.2 mm. The positive correlation between content of polymeric protein (PN) in extracellular polymeric substances (EPS) and AGS stability indicated the important effect of PN on stable operation of AGS syetem. The results of microbial high-throughput sequencing analysis exhibited that Proteobacteria and Bacteroidetes was predominant at phylum level. At genus level, Flavobacterium and Thauera contributed to the EPS secretion and organic pollutants removal, thus playing an important role to the stable operation of AGS. At class level, Gammaproteobacteria beneficial to nitrification gradually became the dominant class during the operation. In addition, there were different nitrogen and phosphorus removal bacteria in the system mainly including Nitrospira, Thauera, Paracoccus, fusibacter, proteocatella, etc.. Nevertheless, the operation of AGS system needed to be optimized to strengthen simultaneous nitrogen and phosphorus removal. The experimental results in this paper can provide significant guidances to the stable operation of AGS system treating actual municipal wastewater.