Effect of Temperature on Performance and Microbial Community Structure of Anaerobic Biofilter-Treated Domestic Wastewater

Abstract

Municipal wastewater methanogenesis is one of the ways to utilize municipal wastewater resources.In this study, a biofilter used to treat actual municipal wastewater was employed to investigate the methanogenesis in a pilot-scale reactor. The method of rapid start-up, the influence of temperature on the reactor performance, and the changes in the microbial structure were investigated in the pilot-scale study. The rapid start-up of the biofilter reactor was achieved by the combination of intermittent and continuous operations. The effluent concentration of SCOD was 60 mg ·L-1at the stable operation stage. The biofilter was operated steadily at a temperature higher than 14℃, the accumulation of volatile fatty acids (VFA) was low, and the effluent concentrations of SCOD and TCOD were 69 mg ·L-1and 90 mg ·L-1, respectively. In addition, the metabolism of hydrolysis and methanogenesis tended to balance off under such conditions. However, the abundance of microorganisms that can hydrolyze organic matter and produce methane decreased. The abundance of Peptostreptococcaceae increased even the temperature was lower than 10℃, which typically increases VFA production. Therefore, the concentrations of effluent VFA and TCOD increased, but methane production decreased. The effluent concentration of SCOD was relatively stable. The microbial abundance and diversity were the richest at 19℃ in the reactor. The acetolactic methanogens were the dominant methanogens at low temperatures. The anaerobic biological filter for the treatment of urban sewage starts quickly and can resist the impact of continuous temperature reduction. Moreover, it does not need backwashing after running for nine months, and it is not easily clogged.Therefore,the functions of biological contact oxidation and filtration retention of the biological filter can be more fully utilized.