EPA/540/R-94/508

The J.R. Simplot Company (Simplot), Pocatello, Idaho, offers a bioremediation alternative to cleaning soils contaminated with nitroaromatics. The Simplot Anaerobic Biological Remediation (SABRE) Process, developed by the University of Idaho, consists of a variety of microbial genera that become active anaerobically at oxidation/reduction potentials of -200 mV or lower. The system is applicable to nitroaromatic contaminants, including nitrotoluene explosives (e.g., TNT) and many pesticides (e.g., dinoseb). Oversize material is removed from contaminated soil, and the soil is then homogenized. The homogenized, contaminated soil is then placed in a bioreactor with a specially prepared water solution in a 1:1 weight ratio. A pH buffer, a carbon source, and a consortium of enhanced nitroaromatic-degrading anaerobic bacteria are introduced into the bioreactor. These bacteria can completely degrade nitroaromatic contaminants to nonaromatic, nontoxic products. The SABRE Process was evaluated under the SITE Program on 39 yd3 of 2-sec-butyl-4,6-dinitrophenol (dinoseb) contaminated soil, at the county owned airport in Ellensburg, WA (Bowers Field). The technology was demonstrated over a 23 day period during June and July 1993. Comparison of the dinoseb levels before and after treatment showed a reduction of greater than 99.8 percent. Other pesticides were also degraded in the process, highlighting the effectiveness of the process even in the presence of co-contaminants. Based upon demonstration results, treatment costs have been estimated at $97/yd3.