Crude oil remediation using plant extract of Guava leaf (Psidium guajava) in soil environment

Epelle Gift Jeremiah, Joy Chukwuemeka Peter Ukpaka and Chukwuemeka Peter Ukpaka

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This study was carried out to evaluate the potential of fermented Guava Leaf (Psidium guajava) fluid extract in bioremediation of crude oil polluted soil. For this purpose, 6reactors were set up and labelled R1 to R6, with R6 as the control. 2kg of soil sample was polluted with 150ml of crude oil and the remediant was added to each reactor. The volume of remediant were varied at increasing order of 20ml to 100ml from R1 to R5. R6 contains no remediant. Samples were taken and analyzed at 4days interval for total petroleum hydrocarbon (TPH) and nutrient content. The study lasted for 20days. At the end of the study period, there was 75.65% and 91.95% decrease in the concentration of TPH in R1 and R5, with the lowest and the highest respectively, compared to 18.44% decrease in R6. Similarly, there was a gradual decrease in the concentrations of total organic carbon, nitrogen, phosphorus, and potassium in all samples. The transient growth of the bacteria and fungi was monitored with respect to the degradation rate of the substrate in each batch bioreactor and the result obtained demonstrates the following phases, lag, progressive or exponential, stationery and death or decline. This reveals the theory of Monod’s model indicating decline in a viable nutrient and substrate utilization in each bioreactor. This research has demonstrated that psidium guajava possess the characteristics of good biostimulant enhancing bioremediation of polluted soil environment.