Increased Biotransformation Efficiency of Chunk-TNT-Contaminated Soil Using Acetone Pretreatments

Publisher Website
Google Scholar
Abstract
Particulate, or chunk 2,4,6-trinitrotoluene (TNT), in soil was found to be recalcitrant to composting down to particle sizes of approximately 2 mm. Evidence for the colonization of TNT surfaces was obtained, but no pitting or otherwise preferential solid TNT solubilization was observed. Acetone pretreatments were used to make the chunk-TNT-contaminated soil more amenable to bioremediation. A pretreatment of acetone slurrying to dissolve and redisperse solid TNT in soil before applying remedial treatments was developed. The well-described treatment of composting was subsequently applied to native and acetone-pretreated contaminated soils. Acetone-pretreated soil responded to composting significantly better than untreated soil. After evaporating off the acetone used as pretreatment, composting microcosms held at 55°C showed sporadic removal from 3000 ppm to 300 ppm TNT in 24 days for untreated soil, while pretreated soil demonstrated conclusive removal from 3000 ppm to 18.1 ppm TNT in 6 days. Separate results indicated that residual acetone from pretreatment without subsequent evaporation was found to delay, but not otherwise inhibit, the compost's ability to degrade TNT. Community level physiological profile testing of 13-day-old composts, with pretreatment and residual acetone, suggests that three significantly different microbiological compost communities were equally adept at degrading the repartitioned TNT. The superior removal rates and efficiencies in the acetone-pretreated systems are likely to be due to the increased availability of TNT to the necessary microflora.