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Transformation of trinitrotoluene to triaminotoluene by mixed cultures incubated under methanogenic conditions
Author(s) -
Hwang Philip,
Chow Teresa,
Adrian Neal R.
Publication year - 2000
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620190408
Subject(s) - trinitrotoluene , bioreactor , wastewater , biodegradation , chemistry , fluidized bed , environmental chemistry , anaerobic exercise , microorganism , pollutant , sewage treatment , methane , explosive material , bacteria , environmental science , environmental engineering , biology , organic chemistry , physiology , genetics
2,4,6‐Trinitrotoluene (TNT) is an explosive widely used by the military. Although it is no longer manufactured in the United States, large amounts of wastewater are generated annually from load, assembly, packing, and demilitarization operations. Granular‐activated carbon adsorption is the standard technology for treating wastewater containing TNT and maintaining discharges within the limits established under the National Pollutant Discharge Elimination System. Studies evaluating biological treatment of pink water with an anaerobic fluidized‐bed, granular‐activated carbon bioreactor have been promising, but the fate of TNT is unknown. We investigated the anaerobic transformation of TNT by biofilm microorganisms obtained from a wastewater treatment plant receiving explosive manufacturing wastewater. The TNT was transformed to a mixture of 2‐amino‐4,6‐dinitrotolune; 4‐amino‐2,6‐dinitrotoluene; 2,4‐diamino‐6‐nitrotoluene; and 2,6‐diamino‐4‐nitrotoluene before culminating in the formation of triaminoto‐luene (TAT). Triaminotoluene was susceptible to further degradation under anaerobic conditions, but its fate was not determined. Methane formation was inhibited but resumed after the depletion of the diaminonitrotoluene isomers. These studies demonstrate near stoichiometric formation of TAT from TNT and the transformation of 2‐amino‐4,6‐dinitrotoluene to 2,4‐diamino‐6‐nitrotoluene and 2,6‐diamino‐4‐nitrotoluene by a mixed culture incubated under methanogenic conditions. This evidence indicates TAT is also a likely end‐product of TNT biodegradation in the anaerobic fluidized bed bioreactor.