BIOREMEDIATION OF ORGANIC CONTAMINATED SOIL

Bioremediation of organic contaminated soil is a treatment technology that, depending on the site-specific conditions, can reduce the organic contaminants to an acceptable level which meets the remediation criteria established by the regulatory agency. This paper presents the results of a pilot program which was conducted during the summer and fall of 1988 to bioremediate about 5,000 cubic metres of polycyclic aromatic hydrocarbons (PAH's) contaminated soil at a former oil gasification plant. The bioremediation of the contaminated soil involved the proper control of the various parameters necessary to enhance the microbial degradation of the organic contaminants. The biotreatment operation resulted in a decrease of all contaminants which were monitored during the course of the study. Benzene, toluene and xylene (BTX) compounds decreased by 73 percent, oil and grease by 36 percent, and PAH compounds by 86 percent. Four and five ring PAH compounds such as pyrene and benzo(a)pyrene (B(a)P) were only reduced by 60 percent. The percentage reduction of PAH concentration decreases as the molecular weight and number of aromatic rings increase.