title: Simple surface foam application enhances bioremediation of oil-contaminated soil in cold conditions.
abstract: Landfarming of oil-contaminated soil is ineffective at low temperatures, because the number and activity of micro-organisms declines. This study presents a simple and versatile technique for bioremediation of diesel-contaminated soil, which involves spraying foam on the soil surface without additional works such as tilling, or supply of water and air. Surfactant foam containing psychrophilic oil-degrading microbes and nutrients was sprayed twice daily over diesel-contaminated soil at 6 °C. Removal efficiencies in total petroleum hydrocarbon (TPH) at 30 days were 46.3% for landfarming and 73.7% for foam-spraying. The first-order kinetic biodegradation rates for landfarming and foam-spraying were calculated as 0.019 d(-1) and 0.044 d(-1), respectively. Foam acted as an insulating medium, keeping the soil 2 °C warmer than ambient air. Sprayed foam was slowly converted to aqueous solution within 10-12h and infiltrated the soil, providing microbes, nutrients, water, and air for bioaugmentation. Furthermore, surfactant present in the aqueous solution accelerated the dissolution of oil from the soil, resulting in readily biodegradable aqueous form. Significant reductions in hydrocarbon concentration were simultaneously observed in both semi-volatile and non-volatile fractions. As the initial soil TPH concentration increased, the TPH removal rate of the foam-spraying method also increased.
authors.affiliation: Department of Environmental Engineering, Kunsan National University, Kunsan 573-701, South Korea. Electronic address: swjeong@kunsan.ac.kr.
authors.forename: Seung-Woo
authors.initials: SW
authors.lastname: Jeong
authors.affiliation: Department of Environmental Engineering, Kunsan National University, Kunsan 573-701, South Korea. Electronic address: tls8@naver.com.
authors.forename: Jongshin
authors.initials: J
authors.lastname: Jeong
authors.affiliation: Department of Life Science, Kyonggi University, Suwon 443-760, South Korea. Electronic address: jkimtamu@kyonggi.ac.kr.
authors.forename: Jaisoo
authors.initials: J
authors.lastname: Kim
mesh_terms: D001673:Biodegradation, Environmental; D003080:Cold Temperature; D015169:Colony Count, Microbial; D004787:Environmental Pollution; D006838:Hydrocarbons; D010578:Petroleum / Q000032:analysis*; D012987:Soil; D012989:Soil Pollutants / Q000032:analysis*; D013499:Surface Properties; D013501:Surface-Active Agents; D014873:Water Pollutants / Q000032:analysis
chemical_list: D006838:Hydrocarbons; D010578:Petroleum; D012987:Soil; D012989:Soil Pollutants; D013501:Surface-Active Agents; D014873:Water Pollutants
keywords: Biodegradation; Diesel; Low temperature; Oil-contaminated soil; Surfactant foam