Natural Attenuation and Biostimulation of Petroleum-Hydrocarbon Contaminated Soil in a Simulated Column

Various physiochemical and biological remediation methods can be used to remediate petroleum-hydrocarbon contaminations. Using microorganisms in biological remediation methods is considered as a cost-effective and environmental friendly solution. In the current research, two bioremediation-type processes, natural attenuation (NA) and biostimulation (BS) were applied to simulate biodegradation of petroleum-hydrocarbon contaminated soil collected from a refinery. During 60 days of operation, 88% and 65% of initial petroleum-hydrocarbon contamination biodegraded in BS and NA modes, respectively. Moreover, population of indigenous microorganisms in the soil column increased noticeably. Both bioremediation bodes showed that they are compatible with first-order reaction kinetic. In the NA mode, reaction rate constant was calculated 0.02 d^-1 while it was 0.039 d^-1 for the BS mode.