Kinetic Modeling and Half-Life Study on Bioaugmentation of Oil Sludge Contaminated Soil by Single and Consortia LIBeM at Different Concentration Levels

The focus of this study is to evaluate the potential of five locally isolated beneficial microorganism (LIBeM) strains, namely, C. tropicalis—RETL-Cr1, C. violaceum—MAB-Cr1, P. aeruginosa—BAS-Cr1, S. paucimobilis—ReTOS-Cr1, S. maltophilia—RAS-Cr1 to treat oil sludge-contaminated soil. The bioaugmentation study was investigated in a lab-scale up experiment over various concentration of oil sludge at 5, 10, 15, and 20% v/v levels. Their efficiency to degrade oil sludge-contaminated soil was carried out within 84 days treatment. A natural attenuation plot was set up as a control to compare the ability of indigenous microbes in a soil with augmented LIBeM added. The results showed that augmented soil with single and consortia LIBeM had a relative significant influence on biodegradation of total petroleum hydrocarbon (TPH) in soil. Analysis of biodegradation rate showed that all treatments obeyed the first-order kinetics model indicated by the high R2 (= 0.99) value that fitted well to the first-order kinetics model. The results showed that soil treated with Consortia 4 (C. tropicalis + C. violaceum + P. aeruginosa) at 10% v/v of oil sludge recorded higher biodegradation rate, k (0.0375 day−1) and lower biodegradation half-life, t ½ (18.5 days), respectively. On the contrary, natural attenuation showed the lowest biodegradation rate, k (0.0044 day−1) and recorded 157.5 days of biodegradation half-life times. This result was 8.5-fold higher as compared to natural attenuation. This study can be very useful as application tools for oil remediation based in soil subjected to prediction of times present in the environment.