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at an ME Site in • • Island , New York ' I Background LFR Levine• Fricke conducted a pilot study to evaluate the efficacy of an ozone and air-sparging system for in- situ treatment of methyl tertiary-butyl ether (MtBE) and benzene, toluene, ethylbenzene and xylenes (BTEX) —I impacted groundwater at a gasoline spill site on Long Island, New York. Two ozone-air sparge points were installed at different depths in a single borehole to maximize the conical diffusion of the gasses in the medium- to coarse-grain sand aquifer. Monitoring wells were installed at twelve and twenty-eight feet downgradient of the sparge points to measure the magnitude of hydraulic effect and to monitor changes in groundwater quality resulting from addition of ozone and air. _ Results NITRE and BTEX Concentrations vs. Time t Pressure data from down-hole transducers and Piot Test Well LFR-a (72' from Ozone Sparge Well) measurements of dissolved oxygen in groundwaterITi l were used to evaluate the area of influence of the sparging system. These data confirmed that the ozone- t ITT- � air sparge system had a down-gradient radius of influence of at least 23 feet. j Changes in MtBE concentration in groundwater were 1 20 monitored and destruction rates estimated using - { analytical results from weekly samples collected from0211 ll ' I F ' I the monitoring points. The graphs at right plot MtBE 0 concentration versus time for LFR-4 ( 12 feet down- ' �� \ ITT IT r � gradient of the sparge well) and LFR 2 (28 feet � � 1291200.7 - 21812001 '�^ C .. J---_� 2� C -'< 1 .x,'001 9M1J/2001 downgradient of the sparge well). Pilot. iest VIPefl LrR- 2 MC hom Orono Sparge Well) - _ After four weeks of ozone-air sparging, MtBE 7000 ps� re — concentrations in LFR-2 decreased from 6,300 parts per billion (ppb) to 1 ,700 ppb, a 73% destruction rate. soon MtBE concentrations continued to decrease for three SoonQMill w f weeks after the four-week ozone-air sparging period 4000 . to 79 ppb, a 99% destruction rate, at week 7. BTEXs 1 concentrations in LFR-2 realized similar decreases. 3000 z " IvItB>E-eoneentratians deereasedrom4-5ppbo 20m —Y m IT 11 ppb in the four week ozone-air sparge period, a to I . e A 11 lip 76% destruction rate. MtBE concentrations continued 1000 , It I to decrease for three weeks after the four-week ozone- 0 air sparging period to 2 ppb, a 96% destruction rate, 1292001 213201[1 2/132007 ?/2812001 M' 1=001 WORM 0/302401 41920G, at week 7. BTEX was not initially detected in this �M E �eno ,oliji enif M, apmare IF o.A,�. MpI "�e well; however a spike in BTEX concentrations L64 occurred after two weeks of ozone sparging. "" ' `"W' 1 Conclusions i LFR has performed a successful pilot clearly demonstrating the efficacy of the ozone and air sparging technology for remediation of MtBE and BTEX impacted groundwater. This innovative remedial technology is a cost-effective and timely alternative for the conventional pump and treat remedial technologies.