Bioremediation of Contaminated Clay Soils

Abstract

This research work demonstrates the feasibility of accelerating bioremediation of a clay soil by supplementing with (NH₄)₂SO₄, KH₂PO₄, sucrose (as an inducer for growth) and tween 80. The soil contained 7% residual gasoil. The bioremediation was stimulated by moisture adjustment to 10%, and inoculating with hydrocarbon degrading microorganisms. (NH₄)₂SO₄ and KH₂PO₄ were added to the soil to obtain soil samples with C:N:P ratios of 100:1.4:1.4, 100:6.4:1.9, 100:11.4:2.4, and 100:21.4:3.4. The C:N:P of 100:11.4:2.4 resulted in more than 78% gasoil removal for duration of two months. Tween 80, in the range of 0-20mL/ (kg soil), was added to the soil samples with C:N:P ratio of 100:1.4:1.4. More than 84% removal was achieved when 10 mL/kg tween 80 was added to the soil. Sucrose, in the range of 0-20 g/(kg soil), was added to the soil samples with the C:N:P ratio of 100:1.4:1.4. For the sucrose level of 20 g/(kg soil), 79% removal was obtained in two months. Additional experiment was also conducted at two porosity levels of 54% and 22%. The removal percentage in the soil with high porosity was almost twice as compared to soil with low porosity.