Vasin Mahatnirunkul. Bioremediation of Hydrocarbon in Contaminated Site. Doctoral Degree(Environmental Technology). มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี. : King Mongkut's University of Technology Thonburi, 2001.
Bioremediation of Hydrocarbon in Contaminated Site
Abstract:
The petroleum hydrocarbons from underground storage tanks at Pluak Daeng district, Thailand, exploded on November 7, 1996. lllegal fuel of more than 200,000 liters flowed down into the unconfined aquifer, about 2 m deep from the groundwater. There were 4 households who received environmental and health impacts. It damaged 10 fruit plants, 3 ponds of soft shell turtle and 2 ponds of fish production. The site assessment and treatability study were conducted in this study area to develop the strategy for soiil and groundwater in situ bioremediation treatment. The study found that after 4 years of spillage, the contaminated plume were located 44 m away from the spillage source. Hydrocarbons in range of C9-11 were found to contaminate the groundwater and the Cl l-20 were trapped in the soil at a domestic well [or point of exposure (POE)] used as a source of water supply. All of the contaminates are not carcinogens as classified by U.S. EPA. Benzene, toluene, ethylbenzene and xylene compounds (BTEX) were not found in the groundwater. The EPA Hydrocarbon Spill Screening Model (HSSM), used for site assessment, indicated that after 6 days of spillage the contaminates flowed down to the groundwater level. After 1 year, the nonaqueous- phase liquid (NAPL) saturation in soil was equal to 14.5% or 35,754 ppm. The lens forming was started after 6 days of spillage which rapidly spreaded during 4 years through a 23 m in distance and after 10 years it spreaded slowly through a 25 m in distance. At the domestic well, it was found that after 5 years of spillage, benzene and toluene were nearly absent. These simulated results are in line with the Department of Mineral Resource (DMR) data and villagers' interviewing data. For a treatability study, it was found that solid-phase reactors (landfming) could degrade the hydrocarbons more rapidly than sluny-phase reactors. When evaluated by natural attenuation and risked-based corrective action (RBCA) approach, it can be concluded that this contaminated area needs treatment during the first 1-3 years of spillage. After that, the contaminated area could be remedied by natural attenuation.