好氧饥饿对膨胀污泥硝化性能及污泥特性的影响

Effects of aerobic starvation on nitrification performance and sludge characteristics of bulking sludge

采用SBR好/缺氧工艺,考察了好氧饥饿对于丝状菌膨胀污泥中硝化细菌活性及污泥性能的影响。结果表明,14 d的好氧饥饿过程(无外加底物,保持曝气)中,氨氧化细菌(ammonia-oxidizing bacteria,AOB)表现出更高的饥饿敏感性,其好氧衰减速率[(0.42±0.06)d-1)高于亚硝酸盐氧化菌(nitrite-oxidizing bacteria,NOB)的好氧衰减速率[(0.34±0.05)d-1]。恢复阶段初期,系统出现了明显的亚硝酸盐积累现象,这主要归因于AOB具有在环境发生改变时做出快速反应的能力,具体体现在AOB较NOB具有更高的活性恢复速率上。此外,好氧饥饿能够快速杀死丝状细菌,迅速改善膨胀污泥的沉降性能,使污泥的SVI由170 ml·g-1快速下降到30 ml·g-1。胞外聚合物(extracellular polymeric substances,EPS)和溶解性微生物产物(soluble microbial products,SMP)能够相互转化,并为饥饿污泥提供一定的碳源和能源,保证了细菌在饥饿环境中长期的细胞维持。

The effects of aerobic starvation on nitrification bacteria’s activity and sludge performance of filamentous bulking sludge were investigated in an aerobic-anoxic SBR process. Ammonia-oxidizing bacteria （AOB） had a higher hungry sensitivity than nitrite-oxidizing bacteria （NOB） in 14 days of aerobic starvation process which was kept aeration and without feed. The decay of AOB [ （0.42±0.06） d-1] was higher than NOB [（0.34±0.05） d-1]. The phenomenon of nitrite accumulation was apparently achieved from the system in the early resuscitation period. This phenomenon was due to that AOB was able to keep their cells in a state of readiness where it was possible to start oxidizing ammonia almost immediately and with the maximum rate after shorter starvation periods. They were thereby able to respond rapidly to changing environmental conditions, which was reflected by the higher activity resuscitation rate of AOB than that of NOB. In addition, aerobic starvation could kill filamentous bacteria and improve the settleability of filamentous bulking sludge quickly. And sludge volume index （SVI） accordingly declined from 170 ml·g-1 to 30 ml·g-1. Extracellular polymeric substances （EPS） and soluble microbial products （SMP） could transform into each other and became the source of carbon and energy for hungry bacteria to guarantee cell maintenance in a long term starvation environment.