Bioremediation of Crude Oil Contaminated Soil Using Emulsifier, NPK Fertilizer and Microbial Agents, Near Kaduna Refinery

The objective of this research is to remediate soil contaminated with crude oil by utilizing an emulsifier, NPK fertilizer, and microbial agents sourced from the vicinity of Kaduna Refining and Petrochemical Company Limited (KRPC). Two distinct sets of soil samples were gathered near KRPC, designated as samples D and P. The experimental method employed was synthesis. Bioremediation was initiated and assessed by separately applying fertilizer (F), bacteria inoculation (B), and emulsifier (E) to the contaminated soil, as well as by combining bacteria inoculation with fertilizer (B and F), fertilizer with emulsifier (F and E), bacteria inoculation with emulsifier (B and E), and a combination of bacteria inoculation, emulsifier, and fertilizer (B, E, and F) on both samples D and P. The effectiveness of bioremediation was evaluated using the weight loss method over a treatment period of 28 days. The results indicated that the initial concentration of the contaminant (oil) was 398 g/kg for sample D and 194 g/kg for sample P. The pH levels of the soil were measured at 5.9 for sample D and 6.2 for sample P. The cation exchange capacity (CEC) was found to be greater in sample P compared to sample D, with values of 32.0 and 30.0 mmol/kg of soil, respectively. Sample P exhibited higher concentrations of cations (Ca2+, Mg2+, K+, and Na+) with concentration values of 3.6, 1.17, 0.50, and 0.22 mol/kg, respectively. The findings revealed that the combination treatment of B, E, and F resulted in the highest percentage of oil degradation (97% for sample P and 95% for sample D), followed by treatment with B alone (96% for sample D and 81% for sample P).