Eletta, O.A.A.Adeniran, J.A.Buari, M.Z.2018-12-182018-12-1820162409-0360http://hdl.handle.net/123456789/1424Introduction of toxic substances from anthropogenic activities in the environment has associated pollution and adverse human health impacts. Oil spills and accidental discharges from oil and gas operations are typical examples that are sequestered by soil which serves as the sink. The study evaluates the effects of process variables on the degradation of crude oil in contaminated soils. Response Surface Methodology (RSM) using Box-Behnken Design (BBD) was used to evaluate and optimise the effects of NPK fertilizer (0.5 - 3.0 g), amount of inoculum (5 – 20 ml) and the degradation time (24 – 72 hr) on the percentage degradation of crude oil in the contaminated soil. Pseudomonas aeruginosa was used for this ex situ bioremediation study while the statistical design expert program (version 9.0.2) was used for the experimental design and data analysis. The coefficient of determination (R2) of the model of the percentage degradation of crude oil in terms of the three factors was 0.99 while the optimum percentage crude oil degradation of 73.88 % was obtained when volume of inoculum, mass of NPK and degradation time were 12.50 ml, 3.00 g and 72.00 hr, respectively. Results obtained from the study can serve as guide for relevant stakeholders and regulatory agencies in the oil and gas industry in choosing good process parameters to achieve a better degradation of crude oil in contaminated sites.ensequesteredbioremediationdegradationoptimizationtoxicityBox-BehnkenArticle