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Kerfoot Technologies Technical Papers Page 1 of 3 i+ HtMEp�lE MbAB015'" ► C3t31; � Pif7LCY� �ti "' 4h1RL3�UCSxrTtCT��1 a� l �iSr�' ,.. ...tee Technical Papers C-SpargeTM Ozone Microspargeng for Raped Removal of MTBE and Benzene By William B Kerfoot, Ph D , LSP and Angus McGrath, Pty D A system called C-SpargingTM which uses ozone/air injected periodically in conjunction with a pulsing atAs xi orad, pump has been demonstrated to reduce MTBE from over 1000 ppb to less than 100 ppb in less than 40 �trr days The rate of decay was found to be a ten-fold reduction in monitoring wells located 3 to 7 meters from the injection point Monitoring was performed weekly during and after treatment alas 74= suza�ao>0 714L e=ve�c 4— Amew=1 What is C-SpargengTM "MFLIYE �. The KVA process of C-SpargingTM, in situ air stripping with micro-encapsulated ozone, combines three- unit operations offering a one-two-three punch to knockout MTBE Firstly, fine bubbles with a high ` xta�rt4si� surface-to-volume ratio are injected into the saturated zone to extract dissolved MT6E from ' contaminated groundwater Secondly, ozone contained within the bubble and thin film around the sqpzw i bubble reacts extremely rapidly to decompose the MTBE into simple products, alcohols, acetate and formate Thirdly, the residual oxygen from the reaction encourages bioremediation which consumes the breakdown products and converts them to carbon dioxide (CO2) and water (H2O) PUMP ne Microsparging is a Patented Technology for In Situ Treatment of Volatile Organic pounds (VOCs) in Groundwater The reaction detoxifies groundwater containing MTBE and BTEX compounds, specifically benzene, e i rapidly to groundwater standards without producing harmful byproducts The reaction is produced with very low ozone concentrations-molar ratios-compared to VOC concentrations in groundwater The SCREEN I ' technology combines the unit operations of air stripping and oxidative decomposition in a single ;i arxist i i process which can be catalytically accelerated In the C-SpargeTM process, air and ozone are injected I stIA> rTe'MYkLvs directly into groundwater through specially-designed spargers to create "microbubbles" that have very ..-.. C9r ,w high surface area-to-volume ratio The Henry's Constant which regulates the partitioning of MTBE from aqueous to gaseous state is about one-tenth that of benzene derivatives However, the surface-to- volume ratio increase of over 30-fold compensates to promote rapid in situ stripping of MTBE As the "microbubbles" rise within a saturated column of groundwater, they extract or "strip" the VOCs from °h aqueous to gas partitioning Upon entering the microbubbles, MTBE and BTEX compounds react with ozone in the gaseous state or in the aqueous "thin layer" surrounding the bubble to decompose MTBE is rapidly degraded with time The rate of decay is similar to that previously reported by Karpel vel Figure i Master Control Uni Leitner, et al (1994) In both bench-scale testing and field testing, ozone microbubbles appeared effective in reducing MTBE concentrations to beyond 90% of original levels (Kerfoot, 2000) The rate of removal has been sensitive to ozone concentration, pressure, and iron silicate content Site Specific System Set-up A single C-Spargero master unit with 6 Spargepointsg was installed upgradient of plume region The unit can be installed with a dual- screened recirculation spargewell which has a lower Spargepoint@ or with isolated SpargepointsO The depth to groundwater was 2 to meters The general construction of a C-Sparge6 consists of a 100 mm casing leading to a 1 S meter screen with 0 5 meter above the water table, a blank casing which was bentonite-sealed in the annular space to prevent short-circuiting, and a lower 1 5 meter screen (10 slot) Alongside this was a 1 5 cm diameter tubing leading from the wellhead region to a 50 mm macroporous Spargepointa 46 cm long with a compression fitting situated below the lower double screen The predominant soil type was gravelly sands Water table level occurred at 2 to 3 meters The predominant contaminated region 0ded vertically from 1 to 3 meters deep The Spargepoints® were installed at a depth of 10 meters http //www kva-equipment com/product php?14,2,28806,ker28806,,,Doc,page html 11/10/2004