ENHANCED BIOREMEDIATION AND VEGETATION REGENERATION PERFORMANCE OF CRUDE OIL POLLUTED SOIL

Enhanced bioremediation of crude oil polluted soil by oil palm bunch ash and sawdust amendments was investigated to determine the capacities of the test materials to enhance degradation of the hydrocarbon content of crude oil polluted soil. One thousand five-hundred gram (1500 g) of soil was placed in each of five buckets labeled CT, NA, BS1, BS2 and BS3. CT (the control) was not given any treatment while the other buckets were each treated with crude oil at 6.7% (v/w) level of pollution. NA was not added any amendment material after pollution. BS1 and BS2 were each mixed with 200 g of oil palm bunch ash and sawdust respectively while BS3 was amended a mixture of 200 g of oil palm bunch ash and 200 g of sawdust. Results showed increase in soil pH from 8.7±0.04 to 10.5±0.06, 5.3±0.01 to 8.5±0.04 and 5.6±0.18 to 11.5±0.15 in BS1, BS2 and BS3 respectively. Percentage total petroleum hydrocarbon content decreased by 65% in BS1 and BS2 and 52% in BS3. Total nitrogen increased from 0.66±0.1 to 0.69±0.0% in BS1, was unchanged in BS2 and reduced from 0.4±0.0 to 0.2±0.0% for BS3 while average phosphorus increased from 0.4±0.0 to 23.0±4.2 mgkg-1, 0.3±0.0 to 1.8±0.4 mgkg-1 and from 0.2±1.0 mgkg-1 to 52.6±4.6 mgkg-1 in BS1, BS2 and BS3 respectively. There were vegetation regeneration in CT, NA, BS2 and none in BS1 and BS3. The amendment materials enhanced bioremediation of crude oil polluted soil but oil palm bunch ash inhibited vegetation regeneration.