USE OF VEGETABLE OIL TO REMOVE NITRATE FROM FLOWING GROUNDWATER

This study investigated the use of vegetable oil to cleanse nitrate fr om groundwater: The hypothesis on which the study was based was that o il trapped in the sail matrix would form an immobile organic zone thro ugh which water flows; nitrate in the water would be removed as microb ial denitrifiers utilized the oil as a carbon source. Laboratory studi es show that the procedure has merit. Both corn and soybean oil rapidl y stimulated native bacteria to remove nitrate from water in static an aerobic bioreactors. Soybean oil/water mixtures ranging from 0.8 to 12 .5% oil in water were tested and all were effective at supporting deni trification. Also, denitrification occurred rapidly at nitrate concent rations up to 2000 ppm NO3-N. In addition to studies with static biore actors, soil column studies were conducted. Soybean oil injected into 2.5 x 34 cm columns containing aquifer matrix or sand removed nitrate from flowing water Flow rates of Icp to 600 mL/day were successful. In nocuous vegetable oil may provide the basis for a simple and inexpensi ve method of nitrate removal from contaminated groundwater.