AWWA ACE99302

Methyl tertiary butyl ether (MTBE), the most common oxygenated fuel additive, had been detected in several drinking water supplies in California. California has listed MTBE as a carcinogen, established an action level of 35 ug/L for drinking water, and a secondary drinking water standard of 5 ppb. The present study investigated the cost and effectiveness of sorption, both as a sole process to remove MTBE from drinking water and as a polishing process after advanced oxidation. Isotherm studies for 1,000 ppb MTBE were conducted using granular activated carbons (bituminous, wood, peat, and coconut) and XAD-4, XAD-8, and XE-572 resins. Non-traditional sorbents such as modified clay materials (treated and untreated greensand) were also tested. Competitive studies were conducted with humic materials from Santa Monica well water and with tertiary butyl alcohol (TBA), a major oxidation byproduct of MTBE. The isotherms showed clear competitive effect of TBA and humics on sorption of MTBE for coconut carbon, whereas for XE-572 resin the competitive effect was not observed. The coconut granular activated carbon (GAC) was the most cost-effective sorbent for use as a sole process and as a polishing process after oxidation. However, it was more expensive to use sorption as a polishing process than to use sorption as a sole process.