BIOTRANSFORMATION OF NITROCELLULOSE UNDER METHANOGENIC CONDITIONS

Treatment of wastewater containing nitrocellulose (NC) fines is a sign ificant hazardous waste problem currently facing manufacturers of ener getic compounds. Previous studies have ruled out the use of biological treatment, since NC has appeared to be resistant to aerobic and anaer obic biodegradation. The objective of this study was to examine NC bio transformation in a mixed methanogenic enrichment culture. A modified cold-acid digestion technique was used to measure the percentage of ox idized nitrogen (N) remaining on the NC. After 11 days of incubation i n cultures amended with NC (10 g/L) and methanol (9.9 mM), the % N (W/ W) on the NC decreased from 13.3% to 10.1%. The presence of NC also ca used a 16% reduction in methane output. Assuming the nitrate ester on NC was reduced to N-2 the decrease in CH4 represented almost exactly t he amount of reducing equivalents needed for the observed decrease in oxidized N. An increase in the heat of combustion of the transformed N C correlated with the decrease in % N. There was no statistically sign ificant decrease in % N when only NC was added to the culture, or in c ontrols that contained only the sulfide-reduced basal medium. The biot ransformed NC has a % N comparable to nonexplosive nitrated celluloses , suggesting that anaerobic treatment may be a technically feasible pr ocess for rendering NC nonhazardous. Copyright (C) 1996 IAWQ.