PARENT SESSION

(PH257) Optimising crude oil degradation in a sandy soil: Effects of urea-nitrogen and phosphoric acid-phosphorus.

Ekweogwu, J. C.¹, Amadi, E. N², Odu, C. T. I.², ¹ Federal University of Technology, P.M.B.1526, Owerri, Imo, Nigeria² Rivers State University of Science and Technology, Port-Hacourt, Rivers, Nigeria

ABSTRACT- Abstract The adverse affects of oil pollution on the soil ecosystem might be prolonged due to the nature of crude oil. It sorbs to soil, overloads it with excess carbon which might not be available for microbial growth, and induces a limitation in soil nitrogen and phosphorus. The effects of the incorporation of urea and potassium nitrate as nitrogen sources, and phosphoric acid and potassium dihydrogen phosphate as phosphorus sources to enhance crude oil degradation in a sandy soil was investigated. Crude oil degradation was determined by the toluene extraction method. The highest degradation of 10.93 ± 0.24% was obtained from samples treated with urea-N/phosphoric acid-P at concentrations of 1000gN/200gPg-1 soil after four weeks incubation. Addition of the surfactant Goldcrew at a concentration of 0.1% (v/w) rather than Corexit to the soil treatment enhanced crude oil degradation. There was no significant (P<0.05) difference between the degradation obtained with the addition of either glucose or starch as alternate carbon substrates, however, the extent of degradation increased with increasing concentrations of glucose up to 2.0% (w/w). The extent of crude oil degradation in the sandy soil was influenced by the sources and concentrations of nitrogen, phosphorus, surfactants and alternate carbon substrates.

Key words: urea and phosphoric acid, crude oil degradation, surfactants, alternate carbon substrates