Crude Oil Remediation in Soil Environment using Orange (Citrus sinensis) Peel

Abstract

The research on effective performance of citrus sinensis (orange) peel was monitored in crude oil remediation in loamy soil environment. Different bioreactors with different bio-stimulant dosage of 20g, 40g, 60g, 80g, 100g of room dry and sundry samples were tested to examine the performance on microbial activities on crude oil mitigation in each bioreactor. The nutrient of the bio-stimulants was determined as pH value of 6.63, total nitrogen content of 4.87%, potassium content of 7.68% phosphorous content of 1.35%, total organic carbon content of 8.21% with microbial counts of 3.84 x 102 cfu/g for sun dried sample. And, the nutrient content of the bio-stimulant subjected to room dried conditions revealed pH value of 6.87, total nitrogen content of 5.61%, potassium content of 9.17%, phosphorous content of 1.68%, total organic content of 9.73% and total bacteria count as5.91 x 102 cfu/g. The research demonstrates that the degree of remediation of the crude oil in the loamy soil was higher in the bioreactor with the room-dry conditioned bio-stimulant than the sun dry. This was attributed to the available nutrient in the room dry sample when compared with the sun dry sample. The research further revealed increased mitigation on the total petroleum hydrocarbon concentration with increase in contact time having a percentage removal of 96.22% for the room dry stimulant and 95.52% for the Sun dry sample mix of 100g stimulant /100ml crude/ 1kg soil. The microorganisms isolated and identified are classified as total heterotrophic bacteria (THB) and total heterotrophic fungi (THF). The increase in microbial population in each bioreactor was dependent on the dosage of the bio-stimulant. Therefore, the order of microbial growth was R5 > R4 > R3 > R2 > R1 > C1 and this characteristic was observed for both sun dry and room dry bioreactors. The biokinetic parameters of specific rate of TPH, maximum specific rate of TPH degradation, dissociation constant of TPH and decay rate constant were determined in this research. Finally, this research has revealed that citrus sinensis (orange) peel is useful as a good bio-stimulant for the treatment of contaminated soil environment for the purpose of restoring the soil integrity for agricultural utilizati.