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i <br /> OZONE MICROSPARGING FOR RAPID MTBE REMOVAL <br /> W11fiam B. Kerfoot(K-V Associates, Inc., Mashpee, Massachusetts) <br /> ABSTRACT: Ozone microsparging allows rapid removal of methyl tertbutyl <br /> ether(MTBE)and benzene, toluene, methyl benzene, xylenes derivatives (BTEX) <br /> encountered at gasoline spill sites Bench-scale testing indicated applicability to <br /> MTBE removal Field testing was performed on two types of sites. (1) a <br /> commercial automotive station which had suffered a gasoline spill, and (2) a zone <br /> upgradient of a water supply well At the former, MTBE and BTEX compounds <br /> were treated, while at the latter only MTBE was present for vestment. The <br /> objective at the station was remediation of sod and groundwater, while the second <br /> site objective was use of a "bubble fence" to control a plume advancing towards <br /> the well. During a 20-day monitoring period at the station site, 95% reduction of <br /> BTEX and 991/o reduction of MTBE was observed in a monitoring well within 18 <br /> ft (5 6 m) of the main injection well The protective bubble fence at the second <br /> site served to reduce exiting MTBE concentrations to non-detect levels <br /> INTRODUCTION <br /> MTBE presents a challenge for effective treatment in groundwater-based <br /> spills A common fuel additive in the United States since the 1990's, MTBE is <br /> resistant to aerobic and anaerobic microbial breakdown (Suflita and Mormile, <br /> 1993) Activated carbon is not a very effective adsorber since MTBE is highly <br /> water soluble and poorly adsorbed (Reisinger, et al., 1986) Because of its <br /> relative low volatility, air stripping systems are capable of removing MTBE only <br /> if exceptionally high air to water ratios are used <br /> Ozone microsparging (the C-SpargeTm process)* appears capable of <br /> effecting rapid removal of MTBE from contaminated groundwaters The use of <br /> microscopic bubbles with high surface-to-volume ratios allows efficient <br /> extraction of MTBE from aqueous to gas phase Differing from its attack on <br /> benzene ring compounds, ozone attack on ether occurs through insertion in the C- <br /> H bond The use of hydrogen peroxide supplementation does not appear <br /> necessary when microbubble ozone is used(Karpel vel Leitner, et al., 1994) The <br /> resultant breakdown products are normally tert-butyl formate, tert butyl acetate, <br /> and tert-butyl alcohol These breakdown products are either further oxidized or <br /> biodegraded rapidly under the aerobic conditions promoted by ozone <br /> decomposition to oxygen. <br /> TECHNOLOGY DESCRIPTION <br /> Ozone microspargmg is a patented technology for in-srtu treatment of <br /> volatile organic compounds (VOCs) in groundwater and surface water The <br /> *U.S Patent#5,855,775, other U S and foreign patents pen it <br />