Physical conditioning to enhance bioremediation of excavated hydrocarbon contaminated soil at McClellan Air Force Base

Abstract

AbstractMcClellan Air Force Base conducted an evaluation of an aerated‐pile composting process and a slurry bioreactor process for biologically treating excavated hydrocarbon‐contaminated soils while controlling emissions of volatile organic compounds. A large aspect of process evaluation was development of soil conditioning steps prior to biological treatment. The conditioning steps evaluated were: soil washing, using trommel and attrition scrubbers; and milling, using rod and hammer mills. Scrubbing was not effective at producing a consistently clean oversize fraction. Milling was effective at reducing the size of larger material and breaking agglomerates. Bioremediation results indicated both processes capable of greater than 90 percent reduction in hydrocarbon levels within 90 days. Aerated‐pile composting was the preferred process because it required less operation and maintenance and more easily handled varying soil characteristics. A full‐scale treatment process was developed and is described.