Fig. 3a showed that more
methane was produced by the biomass from RNand R60 than
R30. This observation implied that the acetoclastic methanogens
became more dominant in microorganisms at longer
SRT. Except the differences mentioned above, similar higher
biomass concentration, biogas yield rate and specific biogas
yield rate were observed in R60 and RN at HRTs of 10 and 8 h
(Table 1). This suggested that the effect of SRT on the treatment
performance of SAnMBR was significant when the SRT
was short, e.g. 30 d. But with a prolonged SRT, especially longer
than 60 d, the effect became less pronounced.