The production, testing, use and disposal of high explosives have extensively contaminated the soil and water at a large number of sites. Several laboratory and field studies have indicated that explosives are toxic at relatively low amounts to a number of organisms, including humans. There is at the time being an urgent need for a simple, cheap and effective technique where explosive compounds in soil and sludge can be degraded in an ecologically sound manner. In the present study a two-step microbiological method was developed where explosive compounds were degraded under shifting anaerobic and aerobic conditions. The method was optimized in a small-scale bioreactor where TNT was mixed with soil, water and substrate and subject to continuous stirring. For the first 8 days anaerobic conditions were applied to the bioreactor and for the remaining 12 days aerobic conditions were applied. Preliminary results show that 75% of the TNT was degraded after four days. The conclusion from the study is that TNT is effectively degraded by the bioreactor technique, and the efficiency can probably be even more improved by certain modification measures.
