温度冲击引起的丝状菌污泥膨胀菌群特征

为探究温度冲击引起的污泥膨胀机理,以生活污水为处理对象,采用SBR工艺分别运行温度骤降系统和温度梯度降低系统,利用Illumina MiSeq高通量测序技术分析温度变化过程中微生物群落整体变化,并对膨胀阶段优势丝状菌类型进行解析.结果表明,温度骤降系统优势丝状菌为微丝菌(Microthrixparvicella),SVI值升高至291mL/g以上,温度梯度降低系统优势丝状菌为Eikelboom Type 0092型丝状菌,SVI值稳定维持在250mL/g,因此Eikelboom Type 0092型丝状菌适宜在温度冲击环境中生长繁殖.温度冲击方式不同导致菌群组成具有差异性,Proteobacteria相对丰度均值为39.3%,其占比在不同阶段变化较小.两个系统在污泥膨胀阶段Actinobacteria和Chloroflexi的相对丰度占比不同.各样本中与去除有机物相关微生物菌群丰度均值为13.6%,Nitrospira其相对丰度均值为2.48%,占NOB总含量80%以上.温度梯度降低系统发生的Eikelboom Type 0092型丝状菌型污泥微膨胀,其出水水质没有发生严重恶化,COD和NH₄⁺-N的去除效果均高于温度骤降系统.

Microbialcommunitycharacteristics offilamentous sludge bulking at temperature shocking environment

Temperature is the key important factor affecting sludge bulking. To investigate the mechanism of sludge bulking at different temperature shockings, themicrobial community structure and dominant filamentous bacteria in sequencing batch reactor (SBR) treating domestic sewage under abruptly/gradually temperature decreasing conditions were analyzed by Illumina MiSeq high-throughput sequencing technology. The results showed that Microthrix Parvicella was the dominant filamentous bacteria in the abruptly temperature dropping system in which the sludge volume index (SVI) increased up to 291mL/g, while filamentous bacteria Eikelboom Type 0092 was the dominant in the gradually decreasing system in whichthe SVI was maintained at 250mL/g. Therefore, temperature shocking can provide more suitable habitat for Eikelboom Type 0092. The temperature varying process will also lead to significant differences in the community structure. The relative abundance of Proteobacteria maintained at average of 39.3%, and showed little variation, but the Actinobacteria and Chloroflexi showed totally different trends. The mean relative abundance of microorganisms related to organic matter removal was stable at 13.6%, and for Nitrospira it was about 2.48% accounting for more than 80% of the total NOB. Limited filamentous bulking (LFB) of Eikelboom Type 0092 caused by gradually temperature decreasing could not lead to serious deterioration of effluent quality, and removal rate of COD and NH₄⁺-N were better than temperature abruptly dropping system.