BIODEGRADATION OF TETRYL (2,4,6-TRINITROPHENYLMETHYLNITRAMINE) IN A SOIL-SLURRY REACTOR

A laboratory study was conducted to determine whether tetryl can be bi odegraded by native soil bacteria under soil-slurry conditions with mo lasses as cosubstrate. A 2-L laboratory reactor was set up with a 15% (weight/volume) slurry of contaminated soil in deionized water. The so il slurry was mixed continuously at 80 r/min. Molasses at 0.3% (volume /volume) was added weekly as a cosubstrate. A no-carbon control reacto r was also set up without molasses addition. The concentration of tetr yl in the soil was monitored periodically. The results showed 100% rem oval of tetryl from the soil within 3 months of operation. In the no-c arbon control, no significant degradation of tetryl was observed. The gas chromatographic/mass spectrometric analysis of the aqueous phase o f the soil slurry showed metabolites identified as trinitro-n-methylan iline, trinitrobenzeneamine, dinitrobenzenediamine, nitroaniline, and aniline. None of these metabolites persisted more than a week after th ey appeared in the reactor system. The parameters relevant to biodegra dation and process control, such as pH, dissolved oxygen, bacterial co unts, and metabolites produced in the reactor, are discussed.