[Performances Analysis of an Upflow Anaerobic Filter for Domestic Sewage Treatment]

Upflow anaerobic filter (UAF) with actual domestic wastewater were examined in this study. The Impacts of hydraulic retention time (HRT) on the performance of a UAF and a primary methanogen group were investigated at mesophilic conditions. The chemical oxygen demand (COD) removal rate was more than 75% after 28 days acclimation at 35℃ and HRT of 24 h. With a gradual decrease in the HRT, the COD removal rate first increased and then decreased. When the HRT was 5 h, the COD removal rate was the highest, with an average 81.71% and a maximum of 87.18%. When the HRT decreased to 2.5 h, the average COD removal rate decreased to 75.12%. The methane produced per unit mass of substrate consumed (CH₄/COD_re) and volume fraction increased with a decrease in HRT. When the HRT was 2.5 h, it reached 0.30 L·g^-1, and the volume fraction of methane was maintained at about 73%. The energy generated by the system met the energy demands of the peristaltic pump. Quantitative analysis of the primary methanogen group in the system indicates that Methanosarcinales is the dominant in the system. With a decrease in HRT, the abundances of acetoclastic and hydrogenotrophic methanogens increased significantly.