某大型造纸废水处理厂的污泥膨胀控制及微生物群落结构分析

Sludge bulking control and microbial community structure analysis of a large papermaking wastewater treatment plant

以一座处理规模为15×10^(4)m^(3)·d^(-1)的造纸废水处理厂污泥膨胀控制为研究对象。通过进水补充氮磷营养物质、进水更换混凝剂去除硫化物,控制系统DO为1.5 mg·L^(-1),选择池加大预曝气等措施改变优势丝状菌的生存环境。经过调控,系统SV、SVI出现显著下降,分别从98%、198 m L·g^(-1)下降至37%、80 m L·g^(-1),恢复至正常范围,从而解决了该厂的污泥膨胀问题。对污泥进行微生物镜检和染色镜检分析发现,该厂活性污泥膨胀主要为Type 021N型丝状菌(发硫菌)和Beggiatoa sp.(贝氏硫细菌)过度繁殖引起的丝状膨胀。对污泥膨胀控制前后的活性污泥进行高通量测序以分析其微生物菌群结构,从种属变化角度发现在污泥膨胀前后,Actinobacteria门中Rhodococcus属占比从2.92%下降为0.19%、Mycolata属占比从0.1%下降为0,Alpha-proteobacteria门中的Meganema属占比从0.14%下降为0、Gamma-proteobacteria中Thiothrix占比从0.18%下降为0.01%。这几种微生物是引起该厂污泥膨胀的主要菌属。本研究案例在解决污泥膨胀问题的前提下,减少了药剂用量,提升了系统处理能力,避免了污泥流失,吨水电耗得以降低,且方法简单易行高效,可为其他同类污水处理厂解决污泥膨胀问题提供参考。

A papermaking wastewater treatment plant with a processing capacity of 15×10^(4)m^(3)·d^(-1) was taken as the research project to study the control of sludge bulking in the process.The living environment of dominant filamentous bacteria was changed by adding nitrogen and phosphorus nutrients to the influent,replacing coagulant with water and removing sulfide.controlling the DO of the system at 1.5 mg · L^(-1),and increasing preaeration in the selection tank.After regulation and control,SV and SVI in the system decreased significantly from 98% and 198 mL·g^(-1) to 37% and 80 mL·g^(-1),respetively,,and returned to the normal range,which successfully solved the sludge bulking problem of the plant.The results showed that the activated sludge bulking of the plant was mainly caused by the overgrowth of Type 021N filamentous bacteria(Thiobacillus sp.) and Beggiatoa sp.Based on the high flux analysis of microbial flora structure of activated sludge before and after sludge bulking control,from the perspective of species change,it was found that before and after sludge bulking,the proportion of Rhodococcus in Actinobacteria decreased from 2.92% to 0.19%,the proportion of Mycolata decreased from 0.1% to 0,the proportion of Meganema decreased from 0.14% to 0,and the proportion of Thiothrix decreased from 0.18% to 0.01%.These kinds of microorganisms were the main bacteria causing sludge bulking in the plant.The solution of this case can provide reference for other similar sludge bulking problems.