Preliminary Study of Biological Activated Carbon Treatment for Removing MTBE from Groundwater

Methyl tert-butyl ether (MTBE) is a common additive for producing a clean burning fuel with a higher Octane number and less emissions. Batch adsorptive capacity, continuous flow breakthrough and biological activated carbon (BAC) treatment experiments were conducted to compare the adsorptive capacities of four activated carbons for MTBE, to obtain the adsorptive capacity indicators useful for predicting the carbon's MTBE capacity and its utilization in actual treatment, and to establish an effective start-up procedure to enable an activated carbon adsorber to function as the desired BAC system for long term treatment without needing carbon replacement. Although the coconut carbon YK's adsorptive capacity for MTBE was much larger, its column loading was only 20% higher than the coal carbon Coal because of its slower intraparticle diffusion rate due to the lack of larger micropores; the YK loading increased >60% when the adsorber flowrate was reduced by 50%. Two inoculation methods were utilized to seed the MTBE degrading bacteria present in the spent activated carbon (Spent) obtained from a remediation site; circulation of the supernatant of the Spent-water mixture to seed the adsorber failed, while the three Spent-filled adsorbers (65, 40 and 100%; the balance was YK) became BAC systems after the start-up period of 5-7 weeks during which the MTBE concentration of the feed increased from 0 to 30 mg/L. Each Spent-filled adsorber removed >50% of MTBE present in the feed (up to 40 mg/L); the more the Spent filled, the faster the BAC function was established.