反硝化悬浮填料适用性及其微生物群落结构解析

为研究温度及处理负荷对缺氧挂膜悬浮填料的活性恢复效果的影响,将填料分别置于低负荷、冲击负荷和低温环境中进行活性恢复适用性实验.结果表明在填料活性恢复过程中起关键作用的是EPS中多糖的增加,冲击负荷和低温条件下多糖含量增加比蛋白质更为明显.而低负荷下多糖和蛋白质含量均高于另外两者.缺氧挂膜悬浮填料的活性恢复对冲击负荷条件的适用性较好,低温条件次之,对低负荷环境适用性较差.另外,低负荷、冲击负荷和低温环境中Proteobacteria菌门的相对丰度分别由15 d时的72.23%、78.66%和76.35%上升至25d时的83.17%、84.30%和80.46%,15 d时低负荷下Proteobacteria菌相对丰度低于其他反应器,缺氧悬浮填料不能作为污水处理厂低负荷下总氮快速达标的备选方案.反硝化功能菌属Dechloromonas相对丰度的增加可能是引起填料生物膜反硝化脱氮能力提高的重要原因.Flavobacterium菌属的存在可能促进了低温下填料生物膜反硝化脱氮能力的恢复.不同恢复环境对缺氧生物膜恢复完成时的生物多样性影响较小.

Applicability and Microbial Community Structure of Denitrification Suspended Carriers

In order to investigate the effects of temperature and organic loading on the bioactivity reactivation of anoxic biofilm in suspended carriers, the experiment was carried out under low organic loading, shock loading and low temperature conditions. The experimental results showed that the increase of polysaccharide in extracellular polymeric substance (EPS) was important during bioactivity reactivation process, and polysaccharide content was higher than that of protein under shock loading and low temperature conditions, and the contents of both polysaccharide and protein were much higher under low organic loading condition. Anoxic biofilm achieved excellent applicability in shock loading condition, moreover anoxic biofilm reactivated under low organic loading had lowest denitrication capacity and anoxic biofilm recovered at low temperature was in between. In addition, the relative abundance of Proteobacteria under low organic loading, shock loading and low temperature conditions increased from 72.23%, 78.66% and 76.35% to 83.17%, 84.30% and 80.46% at the end of the reactivation process (25th day), respectively. However, the relative abundance of Proteobacteria under low organic loading was lower than those of other reactors, indicating that the anoxic suspended carriers were less suitable for total nitrogen removal in wastewater treatment plant. The increase in relative abundance of Dechloromonas was significant for enhancing total nitrogen removal, and anoxic biofilm possessed comparatively rich biodiversity when the denitrification capability was recovered. The presence of Flavobacterium could promote the denitrification capacity of biofilm at low temperature.