Remediation of Crude Oil Contaminated Soil by Enhanced Natural Attenuation Technique

The concentrations of nitrogen, phosphorus, total hydrocarbon utilizing bacteria (thub), totalheterotrophic bacteria (thb) and total petroleum hydrocarbon were determined using the remediation by enhanced naturalattenuation (rena) in a crude oil contaminated farmland in rivers state, nigeria. a tph concentration of 1.1004 x104mg/kg of the sandy soil was achieved after spiking and tilling. there was a reduction in the tph level from 300mg/kgafter 8weeks, to 282mg/kg after 10weeks.no significant reduction in the tph level was observed after the 10th week. thenitrogen and phosphorus levels of the sandy soil were 24.6 and 22.8mg/kg respectively. this suggests that the nitrogen andphosphorus levels could no longer support biodegradation at the residual tph levels of 282mg/kg and 22.8mg/kg afterspiking and tilling respectively, which further reduced to 0.12mg/kg and 1.7mg/kg respectively after 10 weeks. the totalhydrocarbon utilizing bacteria (thub) increased from 3.0 x 10 4cfu/g to 8.55x10 4cfu/g and finally reduced to 5.38 x104cfu/g, while the total heterotrophic bacteria (thb) reduced from 1.22 x10 8 cfu/g to 5.98 x 10 5cfu/g. data of the studyindicate that remediation enhanced natural attenuation technique could be employed to remediate a farm settlement contaminated by crude oil.