Bioremediation of Diesel Contaminated Soil Using Biopiles

Abstract

Ex-situ bioremediation of 500 m3 of diesel contaminated soil was evaluated in a research effort at the Kennedy Space Center. As an alternative to thermal treatment, four biopiles were constructed using sandy, diesel contaminated soil. The biopiles were assembled with a negative pressure aeration system and nutrient/irrigation system. Indigenous biota were effectively enhanced within the biopiles to reduce total recoverable petroleum hydrocarbon (TRPH) levels to within regulatory limits. The effectiveness of the bioremediation process was monitored using three different laboratory test methods. Two of the more traditional techniques include monitoring TRPH levels and biological enumeration. A newer monitoring technique, biological community patterning, was evaluated as an alternative test method to biological enumeration. This technique evaluates the transition of carbon source utilization of the microbial community during the remedial process using multivariate, detrended ordination. The entire remedial process required 12 weeks, during which TRPH levels dropped from 3,000 mg/kg to less than detection limits (10 mg/kg). Including laboratory monitoring and construction, the remediation cost was approximately $50/m3.