Removal of MTBE from water using granular activated carbon

Methyl tert butyl ether (MTBE) has for years been used as a fuel oxygenate in gasoline. It seeps into the soil and underground water sources mainly from leaking underground storage tanks. Since MTBE has a high affinity for water and a low volatility, it is very difficult to treat with conventional treatment processes. Granular activated carbon (GAC) is one of the methods used for the treatment of groundwater. In this project, rapid small-scale column tests (RSSCT) were conducted using Calgon F-400 and F-600 GACs to examine the process efficiency in a variety of groundwaters, specifically five different site waters with widely varying water characteristics were examined to assess the effects of pH, alkalinity, chemical oxygen demand (COD) and other parameters on treatment effectiveness. As the concentrations of COD and BTEX (i.e. benzene, toluene, ethylbenzene and xylene) increased, the capacities and usage rates of the two carbons dropped. On the other hand, as the MTBE concentration in the influent increased, so did the capacity, as is consistent with traditional isotherm behavior. Alkalinity had a negligible effect on carbon capacity. The major finding was that the type of carbon used in this work had a significant effect on GAC performance, with F-600 exhibiting from 1.5 - 2.2 times greater capacity. Although F-600 costs approximately 1.3 times more than F-400; it was the more economical carbon due to its greater capacity for MTBE --Abstract, page iii