Biological treatment of perchlorate in spent ISEP ion-exchange brine

The use of a biological process for perchlorate and nitrate destruction in spent brine from ion exchange processes was evaluated. The salt-tolerant, anaerobic culture consistently reduced perchlorate and nitrate in spent brine to below detection limits within 24 h in the presence of varying concentrations of brine constituents such as salt (3 to 10% NaCl), nitrate (400 to 4,000 mg/L), sulfate (600 to 6,000 mg/L) and pH (5 to 9). These are the first results to show that rapid biological degradation of perchlorate can be achieved in ion-exchange spent brine containing very high NaCl concentrations (up to 10%).