丝状菌污泥膨胀对脱氮除磷功能菌群的影响

丝状菌引起的污泥膨胀或生物泡沫是活性污泥法污水处理厂运行管理中经常碰到的异常问题,为确定丝状菌引起的污泥膨胀对脱氮除磷系统功能菌群的影响,采用形态学鉴定和Illumina MiSeq高通量测序对5座城市污水处理厂非膨胀期和膨胀期活性污泥、生物泡沫中关键微生物菌群分布特征进行分析研究.结果表明,污泥膨胀和生物泡沫主要由微丝菌(Microthrix parvicella)引起,膨胀期污泥和生物泡沫中微丝菌最高比例达6%和38%.主要脱氮除磷菌属为亚硝化单胞菌(Nitrosomonas)、硝化螺菌(Nitrospira)、陶厄氏菌(Thauera)和Candidatus Accumulibacter phosphatis.膨胀期与非膨胀期相比AOB和聚磷菌相对丰度明显降低,最大变化比例为54%和47%,反硝化菌相对丰度显著升高,最大变化比例为73%;脱氮除磷菌群的波动变化受污泥膨胀的影响外,还与处理工艺及菌群的生理特性相关.

Effect of Denitrification and Phosphorus Removal Microorganisms in Activated Sludge Bulking Caused by Filamentous Bacteria

Activated sludge bulking or foaming caused by filamentous bacteria is a frequent problem in the operation and management of wastewater treatment plants. To clarify the effect of filamentous bacteria sludge bulking on the functional flora in the biological denitrification and phosphorus removal system, morphological identification and Illumina MiSeq sequencing were applied to investigate the distribution of key micro-flora from the non-bulking period, sludge bulking period, and biological foaming period in five municipal wastewater treatment plants. The results showed that the sludge bulking and biological foaming were caused by Microthrix parvicella when the maximum contents were 6% and 38%, respectively. The main bacteria for denitrification and phosphorus removal were Nitrosomonas, Nitrospira, Thauera, and Candidatus Accumulibacter phosphatis. Compared to the non-bulking period, the relative abundance of AOB and PAO was significantly decreased when the maximum contents were 54% and 47%, respectively, during the bulking period. In addition, the relative abundance of denitrifying bacteria was significantly increased when the maximum content was 73%. The fluctuation of micro-flora for denitrification and phosphorus removal was affected by the activated sludge bulking and was related to the treatment process and physiological characteristics of the bacteria.