Abstract
This paper describes that evaluation of soil remediation contaminated with oil on quicklime process and the effect of the treatment for oil degradable bacteria in the soil. In this paper, two different contaminated sites were used. When quicklime method was applied for a contaminated site, the temperature of soil increased over 60 °C by reaction heat and the pH value also rose to about 12. Although the density of bacteria in the contaminated soil decreased from 40 to 5 - 10 x 1010 cells/g-dry soil, they could survive against the increasing of heat and alkalinity caused by the treatment. Some oil degradable bacteria were isolated from original contaminated and treated soil and the abilities of oil degradation were evaluated. These bacteria might contribute the degradation of remained oil in the treated soil. On another site, the oil concentration in soil decreased from 3,555 to 1,430 mg-oil/kg-soil by the treatment. In this case, some light parts of oil, C6 to C10 and C10 to C28, were almost volatized to below 5 and 35% respectively, but the heavy part, C28 to C44 was still remained. However the remained oil decreased gradually after the treatment to 250 mg-oil/kg-soil within 6 month. This shows the high possibility of oil remediation by oil degradable bacteria which survive in contaminated soil against the treatment.
