耐冷氨氧化功能菌群的富集及其对A2/O系统的生物强化

为提高北方地区冬季污水生物处理系统的脱氮效果,利用序批式反应器(SBR)和选择性培养基在(14±1)℃下驯化并富集耐冷氨氧化功能菌群,并采用软性填料进行固定,对(14±1)℃运行的A²/O系统好氧段进行生物强化。结果表明,连续运行5个周期后,SBR中的活性污泥逐渐演替为氨氧化功能菌群,在进水NH₃-N为205～236 mg·L^-1时,SBR的NH₃-N去除率可达79.5%;将组合式纤维填料置于SBR中并继续运行5个周期,可将氨氧化功能菌群以生物膜的形式固定于填料表面。以固定化氨氧化功能菌群对A²/O系统进行生物强化,在投加量为3.24%(污泥干重)的条件下,A²/O系统的氨氮平均去除率由投加前的65%提高到78%,COD和总氮去除率也有明显提高。在生物强化后的持续运行中,A²/O系统的氨氮去除效能有缓慢下降趋势,其长期强化效果有待进一步探讨。

Domestication of a cold-adapted ammonia-oxidizing functional flora and its bioaugmentation on A2/O wastewater treatment process at low temperature

In order to enhance nitrogen removal of sewage treatment processes in cold areas or seasons,a cold-adapted ammonia-oxidizing functional flora was obtained by domestication of activated sludge and used to augment the ammonia oxidation function in an anaerobic-anoxic-aerobic(A²/O)process operated at(14±1)℃.The seed sludge was collected from the secondary sedimentation tank of a local urban sewage treatment plant and domesticated in a sequencing batch reactor(SBR)for five operational cycles with selective medium at(14±1)℃.Loading with semi-soft fiber filler,the SBR was operated for another five operational cycles to immobilize the cold-adapted ammonia-oxidizing functional flora.The results showed that the ammonia oxidation capacity of the inoculated activated sludge was enhanced remarkably after domesticating for the five operational cycles with NH₃-N removal of 79.5% when the initial NH₃-N ranged from 205-236 mg·L^-1 in the SBR.After the next 5 operational cycles the cold-adapted ammonia-oxidizing functional flora was immobilized on the filler as biofilm.When the cold-adapted ammonia-oxidizing biofilm was put into the aerobic pool of the A²/O process with a mass ratio of 3.24%,the average ammonia removal in the process increased from 65% to 78%.The COD and total nitrogen removal was significantly improved as well.However,the ammonia removal in the low temperature A²/O process dropped slowly along with running time.Thus,the bioaugmentation effect in the long run should be investigated in the future.