Influence of Organic Waste on Bioremediation of Oil-Contaminated Soil

As the transportation sector develops and urbanization increases, so does the demand for automobiles and work-shop or garage services. During maintenance or workshop activities, oil may be discharged into the environment, leading to oil-contaminated soil. This study focused on optimizing the use of local organic waste to improve the bioremediation of oil-contaminated soil. The concentration of oil-contaminated soil was mixed with various organic wastes (cow manure, chicken droppings, and sewage sludge) in different ratios of organic waste (R1 100 g, R2 200 g, R3 300 g) combined with 1000 g of soil for a 56-day bioremediation trial. The results showed that the oil-contaminated soil in the case study area varied from 96.07 mg·kg -1 to 123.11 mg·kg -1 . Organic wastes used contained higher levels of organic carbon, nitrogen, and phosphorus compared to the oil-contaminated soil. After 56 days, the treated soil exhibited a reduction of oil contamination by 66.9% with cow manure (CM), 61.6% with sewer sludge (SS), and 79.2% with chicken droppings (CD). The soil mixed with CD had the highest bacterial count (35·10 6 CFU·g -1 ), while the soil mixed with SS had the lowest bacterial count (22·10 6 CFU·g -1 ). Optimal bacterial counts were observed over the 35-day experiment, followed by a decrease in bacterial counts in all reactors. This study demonstrated that the promising technology of utilizing local organic waste has the potential to enhance bioremediation in oil-contaminated soil.