A strengthen circulation anaerobic reactor (SCAR) treating artificial municipal wastewater was investigated under different volumetric loading rate(VLR) and the reactor performance, characteristics of granular sludge and microbial community structure were also tested in this experiment. The results of the experiment demonstrated that the hydraulic retention time (HRT) of 6h could be regarded as the key parameter dominating the efficient operation of SCAR reactor, in which condition the COD removal efficiency was above 75%. The coenzyme F420and the maximum specific methanogenic activity (SMA) of granular sludge increased with increasing VLR, and the EPS contents, especially TB-EPS in the granule sludge also increased obviously. Consistently, the characteristics of anaerobic granular sludge and the removal efficiency of the reactor were influenced by both sludge loading and HRT. The microbial community structure and its spatial distribution in the reactor were also affected by sludge loading, while the relative abundance of the microbial community with different metabolic characteristics in different spatial positions changed with the adjustment of the sludge loading.
Keywords: EPS; activity of sludge; microbial community; municipal wastewater; particle size distribution; strengthen circulation anaerobic reactor (SCAR).