Enhanced dechlorination of Aroclor 1242 in an anaerobic continuous bioreactor

Disappearance of Aroclor 1242 was observed in a continuously operated upflo w anaerobic sludge bed (UASB) reactor inoculated with granular anaerobic sl udge. To distinguish between sorption and dechlorination processes, extract ion of Aroclor from the sludge was performed along with the measurements of chloride and Aroclor in the reactor effluent. A release of inorganic chlor ide combined with the enrichment in lightly chlorinated congeners was obser ved. Based on the chloride balance, the dechlorination process was found to be Aroclor concentration-limited at an Aroclor load of 0.4 mg/(g VSS day) due to a low solubility of Aroclor in water. While an addition of Tween 80 to the influent stream improved solubility of Aroclor, it led to self-inhib ition of the dechlorination process at a load of 1.3 mg/(g VSS day). The ma ximal dechlorination rate observed in this study was 0.6 mg Aroclor/(g VSS day). Crown Copyright (C) 1999 Published by Elsevier Science Ltd. All right s reserved.