The MIXFLO system was successfully used for the $54-million bioremediation of the petroleum and petrochemical waste lagoon at the French Limited Superfund Site in Crosby, Texas (Bergman, Greene, and Davis 1992; French Ltd. 1992; Sloan 1987). In about five months, the chlorinated organics and mono- and polyaromatics were reduced from 1000+ to 100— ppm. The average rate of this aerobic treatment was 0.36 kg BOD/m3/day, which is about half the rate of air or aerobic municipal sewage digestion. This rate is remarkable, considering contaminant character. Benzopyrene was reduced from 2000 ppm at day 100 to 20 ppm at day 200, benzene from 800 to 20, vinylchlo-ride from 300 to 25, and total PCBs from 80 to 9. In November 1992 at day 300, all levels were below 8 ppm.
Project costs included $1.3 million for 18,000 tn of liquid oxygen delivered to the site at $72/tn; $0.7 million for pumping power at $0.05/kWh, and $0.8 million for other power costs. Onsite incineration would have cost $125 million.
FIG. 7.35.5 Schematic diagram of the VENTOXAL system and its oxygenation efficiency. (Reprinted, with permission, from M.D. Matson and B. Weinzaepfel, 1992, Use of pure oxygen for overloaded wastewater treatment plants: The Airoxal Process, Water Environment Federation, 65th Annual Conference and Expo, New Orleans, LA, Sept. 25, 1992, paper AC92-028-007.)
FIG. 7.35.6 The Praxiar Inc. In-Situ Oxygenator (Reprinted, with permission, from G.E. Storms, 1993, Oxygen dissolution technologies for biotreatment applications, Tarrytown, N.Y.: Praxair Inc.)
ORIGINAL PLANT: BOD REMOVAL 90%: 1431 kg/day
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