Remediation of crude oil polluted soil using ash made from oil palm empty fruit bunches (OEFB)

Author(s): I.A.Udoetok, N.W.Akpanudo, F.E.Ekpo

Samples of garden topsoil (0 – 15cm) at atmospheric temperature and about 50% moisture content, with no previous history of pollution were spiked with 100mL Bonny light crude oil. The soil-oil mixture (250g of soil to 100mL of oil) was treated with ashmade fromoil palmempty fruit bunches and allowed to stand for two weeks, with the aim of elucidating the ability of the ash to degrade petroleum hydrocarbons present in the oil. Results obtained from the study reveals that two weeks after the treatment, there was complete removal of the saturated hydrocarbons (TPH) and a significant degradation of polycyclic aromatic hydrocarbons (PAHs). This degradation was affirmed by the reduction of the TPH of the treated sample from9,743.0 mg/kg to zero and PAH concentration from237,230.90mg/kg to 19,107.00mg/kg. The striking feature of this degradation pattern is the fact that though PAH water solubility, and thus bioavailability, decreases with an increase inmolecular mass of oil. Highmolecular weight PAHs like indeno - (1,2,3 – c,d) pyrene and 1,1,2-Benzoperylene were completely degraded whereas lower molecular fractions like fluoranthene and pyrene were still available. Thismay be attributed to the treatment of soil-oilmixture with ash made from oil palm empty fruit bunches which has rich concentration of nutrients like phosphate, nitrate and the metal ions such a potassium. It may therefore be deduced from the above that ash made fromoil palmempty fruit bunches can be used for bioremediation of crude oil contaminated soil.

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