The Use of Oil Palm Bunch Ash for Amelioration of Crude Oil Polluted Soils

The use of Oil Palm bunch ash for the amelioration of Crude Oil polluted soil was investigated at six amendment levels (10g, 20g, 30g, 40g, 50g and 60g) per 2kg soil. A further investigation of the cumulative effect of oil palm bunch ash at the above amendment levels were carried out. Experimental soils were subjected to Laboratory analysis using standard analytical methods for soil pH, organic carbon, organic matter, total nitrogen, available phosphorus and total hydrocarbon content. Soil chemical property analysis indicated increase in soil pH value for soils amended with oil palm bunch ash over time thus reducing soil acidity for enhanced degradation. Soil organic carbon and organic matter increased with levels of amendment material over time. Soil total Nitrogen was generally deficient in soils. However, there was improvement at the end of experimentation. Soil available phosphorus increased with amendment levels and was subsequently depleted in soils over time. At the end of experimentation, there was improvement in soil available phosphorus. Soil carbon, Nitrogen (C/N) ratio was observed to narrow down overtime in soils amended with oil palm bunch ash. Soil total hydrocarbon analysis indicated a significant reduction in amended soils at 20g, 30g and 40g/2kg amendment levels with 28.99% to 30% reduction of total petroleum hydrocarbon content for residual treated soils while cumulative treatment indicated optimum significant reductions at 40g/2kg with 29.34% reduction of TPH content. The finding of the work shows that Oil palm bunch ash amendment at the rate of 20g to 40g/2kg soil is the optimum treatment for remediation while cumulative application would favour the six levels of amendment with 40g/2kg as optimum. Keywords: Bioremediation, Biostimulation, Cumulative treatment, Residual treatment.