This study investigated the performance of an autohydrogenotrophic membrane biofilm reactor (MBfR) to remove nitrate from water with high sulfate concentrations. The results of simulated running showed that TN removal could be over than 98.8% with the maximum denitrification rate of 134.6 g N/m3 d under the conditions of the influent sulfate concentrations of 300 mg SO42−/l. The distribution ratio of H2 electron donor for nitrate and sulfate was 70.0 : 26.9 at the high influent loading ratio of sulfate/nitrate of 853.3 g SO42−/m3 d : 140.5 g N/m3 d, which indicated that denitrification bacteria (DB) were normally dominated to complete H2 electron with sulfate bacteria (SRB). The results of molecular microbiology analysis showed that the dominated DB were Rhodocyclus and Hydrogenophaga, and the dominated SRB was Desulfohalobium, under the high influent sulfate concentrations.
