AWWA ACE54415

Continuous-flow granular activated carbon (GAC) bioregeneration experiments were conducted at different empty bed contact times (EBCTs) using mixtures of biodegradable (benzene, toluene) and nonbiodegradable (perchloroethylene, carbon tetrachloride) synthetic organic chemicals (SOCs). The GAC was pre-equilibrated with respect to each combination of SOCs to observe the biggest effect on bioregeneration performance. If no dissolved oxygen limitations occurred in the bioregeneration experiments, the effluent biodegradable SOC concentration decreased over time and then remained low, after which the effluent nonbiodegradable SOC concentration also decreased because of the increased availability of adsorption sites on the GAC. Pre- and post-experimental GAC loadings show a marked decrease in the biodegradable SOC loading as well as an increase in the nonbiodegradable SOC loading. Larger amounts of bioregeneration were found for higher SOC concentrations and longer EBCTs. Bioregeneration ranged from 30 to 45% of the initial loading after 13-14.5 days. These results illustrate an increase in GAC service life for nonbiodegradable SOCs through bioregeneration of GAC containing biodegradable SOCs. Includes 13 references, table, figures.