The H2-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 H2 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 H2 and high nitrate loading rates of 15 to 80 g/m2 d, nitrate removal fluxes ranged from 2.5 to ∼6 g/m2 d, which are the highest fluxes observed when treating 30 g/L IX brine. However, percent removals were low, and the H2 pressure probably limited the removal flux.
Keywords: flux, membrane biofilm reactor, NaCl, nitrate removal