Bioremediation of HMX-contaminated soil using soil slurry reactors

Soil in some parts of the Iowa Army Ammunition Plant in Surlington, Iowa, was contaminated with cyclotetramethyleneter-anitramine, commonly known as high melting explosive (HMX). A laboratory treatability study was conducted to find out the ability of the native soil bacteria present in the contaminated site to degrade HMX. The results indicated that the HMX can be removed effectively from soil by native soil bacteria through a co-metabolic process. Molasses, identified as an effective co-substrate, is inexpensive, and this factor makes the treatment system cost-effective. The successful operation of aerobic-anoxic soil slurry reactors in batch mode with HMX-contaminated soil showed that the technology can be scaled up for field demonstration. The HMX concentration in the contaminated soil was decreased by 97% in 4 months of reactor operation. The advantage of the slurry reactor is its simplicity of operation. The method needs only mixing and the addition of molasses as cosubstrate.