The carrier anaerobic baffled reactor (CABR),which combines with the characteristics of ABR and the advantages of biofilm reactor,is a suitable technology for decentralized domestic sewage treatment in rural areas of China.In order to improve the treatment efficiency and reduce the investment,it is essential to optimize the structure of CABR.On the basis of our study and analysis of hydromechanics and chemical reaction engineering,the CABR tended to show a state of plug flow as the number of compartments in the CABR increased.The CABRs had good structural performance,with a dead zone ranging from 8.04%—12.69% at the hydraulic retention time (HRT) of 48 h.In terms of chemical reaction engineering,the reaction rate of CABRs with 4,6,8 and 12 compartments were equivalent to that of the CSTRs of 148.35%,181.82%,175.40% and 185.81% times volume,respectively.When the effectiveness and capacity of the reactor were considered,a CABR with 6 compartments was found to be optimal.
