溶解氧对活性污泥系统的脱氮效果和硝化细菌群落结构的影响  

Effects of dissolved oxygen concentration on nitrogen removal and nitrifying bacterial community structure in an activated sludge system

作　　者：刘国华[1] 陈燕[1] 范强[1] 徐相龙 王洪臣[1] 

机构地区：[1]中国人民大学环境学院,北京100872

出　　处：《环境科学学报》2016年第6期1971-1978,共8页Acta Scientiae Circumstantiae

基　　金：中央高校基本科研业务费专项资金(No.13XNLF04)~~

摘　　要：通过改变推流式活性污泥系统曝气池内的溶解氧(DO)浓度,考察了DO对脱氮效率的影响,以及硝化细菌的群落结构和多样性随DO浓度降低的变化规律.水质监测结果显示,系统曝气池中DO浓度从3 mg·L^(-1)降低到0.5 mg·L^(-1)运行时,曝气池中的硝化和脱氮效果并未受影响,且氨氮和总氮的去除效果可分别达到98%和85%以上.当DO浓度进一步降低到0.3 mg·L^(-1)和0.2 mg·L^(-1)时,系统的脱氮效果变差,而且难以达到稳定状态.PCR-DGGE和基因测序分析结果显示,氨氧化细菌(AOB)和亚硝酸盐氧化细菌(NOB)所属的Nitrospira的群落结构随DO的变化并不显著,群落结构的动态变化水平分别为20%~40%和10%~40%.Nitrobacter的群落结构随DO浓度的降低发生了明显的变化,不同DO工况下的Nitrobacter群落结构存在较大差异.测序结果显示,AOB中的Nitrosomonas oligotropha,NOB中的Group1 Nitrobacter和Group 1 Nitrospira均是低DO条件下贡献硝化作用的硝化细菌.因此,在低DO(0.5 mg·L^(-1))工况下,完全可以实现稳定的硝化作用,这为污水处理厂降低DO运行提供了可靠的理论依据.The effects of dissolved oxygen（ DO） on nitrogen removal efficiency and nitrifying bacterial community structure in a plug-flow activated sludge system with anoxic-aerobic（ A / O） mode were evaluated. The water quality monitoring results show that the nitrification and nitrogen removal efficiencies did not decreased when DO was reduced from 3 mg·L^-1 to 0.5 mg·L^-1,and the mean ammonia and total nitrogen（ TN） removal rate reached to more than98% and 85%,respectively. When DO was further reduced to 0. 3 mg·L^-1 and 0. 2 mg·L^-1,however,the nitrogen removal efficiencies of the system became unstable. The PCR-DGGE analysis results show that the dynamic change level for ammonia-oxidizing bacteria（ AOB） and Nitrospira were 20% -40% and 10% - 40%,respectively,indicating that DO change had a little effect on their community structure. However,the Nitrobacter community structure changed a lot when DO decreased. The sequencing analysis indicated that Nitrosomonas oligotropha,Group1 Nitrobacter,and Group 1 Nitrospira mainly contributed to the nitrification under low DO conditions（ ≤1 mg·L^-1）. The system enabled the complete nitrification under low DO level（ 0.5mg·L^-1）,which can provide evidence for reducing DO in a wastewater treatment plant（ WWTP）.

关 键 词：活性污泥系统 推流式 低DO 完全硝化 硝化细菌 

分 类 号：X703[环境科学与工程—环境工程]