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INITIAL PHASE OPTIMIZATION FOR BIOREMEDIATION OF MUNITION COMPOUND-CONTAMINATED SOILS
Citation:
Funk, S., D. Roberts, D. Crawford, AND R. Crawford. INITIAL PHASE OPTIMIZATION FOR BIOREMEDIATION OF MUNITION COMPOUND-CONTAMINATED SOILS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/474.
Description:
We examined the bioremediation of soils contaminated with the munition compounds 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine, and octahydro-1, 3,5,7-tetranitro-1,3,5,7-tetraacocine by a procedure that produced anaerobic conditions in the soils and promoted the biodegradation of nitroaromatic contaminants. his procedure consisted of flooding the soils with 50 mM phosphate buffer, adding starch as a supplemental carbon substrate, and incubating under static conditions. erobic heterotrophs, present naturally in the soil or added as an inoculum, quickly removed the oxygen from the static cultures, creating anaerobic conditions. emoval of parent TNT molecules from the soil cultures by the strictly anaerobic microflora occurred within 4 days. he reduced intermediates formed from TNT and hexahydro-1,3,5-trinitro-1,3,5triazine were removed from the cultures within 24 days, completing the first stage of remediation. he procedure was effective over a range of incubation temperatures, 20 to 37 degrees C, and was improved when 25 mM ammonium was added to cultures buffered with 50 mM potassium phosphate. mmonium phosphate buffer (50 mM), however, completely inhibited TNT reduction. he optimal pH for the first stage of remediation was between 6.5 and 7.0. When soils were incubated under aerobic conditions or under anaerobic conditions at alkaline pHs, the TNT biodegradation intermediates polymerized. olymerization was not observed at neutral to slightly acidic pHs under anaerobic conditions.