Effect of NaCl on nitrate removal from ion-exchange spent brine in the membrane biofilm reactor (MBfR)

摘要

The H _2-based membrane biofilm reactor was used to remove nitrate from synthetic ion-exchange brine at NaCl concentrations from ～3 to 30 g/L. NaCl concentrations below 20 g/L did not affect the nitrate removal flux as long as potassium was available to generate osmotic tolerance for high sodium, the H _2 pressure was adequate, and membrane fouling was eliminated. Operating pHs of 7-8 and periodic citric acid washes controlled membrane fouling and enabled reactor operation for 650 days. At 30 psig H _2 and high nitrate loading rates of 15 to 80 g/m ~2 d, nitrate removal fluxes ranged from 2.5 to ～6 g/m ~2 d, which are the highest fluxes observed when treating 30 g/L IX brine. However, percent removals were low, and the H _2 pressure probably limited the removal flux.