Potential of biowastes to remediate diesel fuel contaminated soil

The unintended release of hydrocarbons into the environment can negatively impact human and animal health, and could further change the characteristics of soils. The aim of the present work was to investigate the rate of biodegradation at 10 and 20% diesel fuel in contaminated soil amended with 10% of three different organic wastes (tea leaf, soy cake, and potato skin) for a period of 126-days. 82 and 25% oil loss was recorded in soil amended with soy cake at 10% and 20 % oil pollution, respectively. Diesel fuel utilizing bacteria counts were high in all organic wastes amended treatments, ranging from 150×106 to 176 ×106 CFU g-1 of soil, compared with the unamended control soil which gave 23 ×106 CFU g-1. Dehydrogenase activity in soil was markedly enhanced by the application of organic wastes. Diesel oil composition monitored by GC/MS indicated complete degradation of n-C9 – C12. First-order kinetic model showed that among the three organic wastes used, soy cake had the highest biodegradation rate constant of 0.153 day−1 at 10% oil pollution, while biodegradation rate was 0.033 day−1 at 20% oil pollution. The results showed there is potential for soy cake, potato skin and tea leaf to enhance biodegradation of diesel in contaminated soil.