Treatment Performance And Microbial Community Dynamics At Different Temperature In A Hybiy A/O Process

With the rapid development of economy in Songhua River watershed in recentyears, the large amount of sewage produced from both sides along the river hasdischarged into the Songhua River water, leading to serious deterioration of the riverwater quality, which has restricted the development of the region along the river andthreatened the resident’s drinking water safety. Due to the low winter temperature innortheast China and long duration time, the biological nitrogen removal process faceswith a lot of challenges, where municipal wastewater treatment plants run poorerdischarge water at winter. It’s difficult to meet the water discharging standard.Therefore, the research of low temperature sewage strengthening treatmenttechnology is of great significance. This paper bases on the A/O process by themeasure of adding the carrier to reinforce. The mian purpose of this study is toinvestigate the performance in a hybrid A/O reactor under different temperatues andanalyze the change of the microbial community composition and diversity in thereactor through high-throughput sequencing technology.According to our research, the average removal rate of COD were90%,90.8%,90%and89%respectively in the hybrid A/O reactor at25℃,15℃,10℃and5℃.The COD effluent can meet the national discharge standard. The average removal rateof ammonia were99%,98%,98%and85%respectively, while the ammonia can notup to discharge standard at5℃. The average TN removal were75%,67.2%,72.5%and60%respectively, when temperature at15℃and5℃can’t satisfy. Thedecreasing temperature has little effect on organic matter removal effect, and hasobviously influence on ammonia and TN removal. However, the continuous runningreactor under low different temperature can realize the stability of nitrification effect.The microbial community compositions are analyzed under different temperaturein the reactor. From the results, the community compositions are mainly divided into13phyla,16classes,25genus, where dominant phyla are Proteobacteria andBacteroidetes. Betaproteobacteria and Sphingobacteria are two major classes. On theanalysis of16genus,9genus are heterotrophic bacteria, including4genus with thefunctions of denitrification. The main bacteria show different degree of change at different classification level. The microbial community relative abundance locatedinto suspended sludge reduces, while diversity of bacterial community locatd intobiofilm increases with the decreasing temperature.Diversity analysis results show that the highest diversity is located into25℃suspended sludge, the diversity located into15℃suspended sludge and biofilm arenearly equal. At the same time, bacterial community diversity located into suspendedsludge reduces, while diversity of bacterial community locatd into biofilm increaseswith the decreasing temperature.