Abstract:Through comparing immobilization of sulfate-reducing bacteria and methanogen on the surface of Polyacrylonitrile based carbon fiber (PAN-CF), polyvinyl alcohol (PVA) fiber and polyacryonitrile (PAN) fiber, two kinds of bacterium on PAN-CF showed higher immobilization velocity, better biological activity and higher removal rate for sulfate and COD than on other carriers. Those results were probably concerned with high hydrophobicity and good biocompatibility of PAN-CF. The experiments,treating wastewater with high concentration of sulphate by means of two-phase anaerobic method, showed that PAN-CF as biofilm carrier had an obvious advantage: there was a big increase in COD/SO42- ratio in effluent of acidogenic phase; the COD removal ratio in methanogenesis phase was 1.5 to 1.8 times of the PVA and PAN carriers; the sulphate concentration was very little effect on the removal ability of COD in the two-phase anaerobic reaction, thus it was better to achieve the aim of two-phase separation and to advance biodegradation of COD.