Microbial Requirements for In Situ Biotreatment of Explosives.
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
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The biological destruction of explosives in soil depends upon several factors in addition to the presence of suitable microorganisms or microbial consortia. Successful bioremediation requires sufficient moisture, nutrients, and co-substrates additives at optimal concentrations. Enhancement of bioavailability by stimulating increased desorption of the contaminant from soils may also be required. Objectives of this study were to develop simple tests to determine the chemical compounds required to stimulate TNT destruction by native microorganisms and the specific combination of additives required to support the most efficient destruction of TNT under static conditions simulating surface application of additives in the field. A three-tiered test system was developed to meet these objectives. Tier I consisted of a previously developed screening test this was used to determine the presence of TNT-degrading microorganisms and cosubstrates required to support microbial degradation. Tier II consisted of a shake flask test that was developed to determine the combinations of nutrients, cosubstrates, andor surfactants required to enhance TNT removal with minimal production of undesirable products. Results of shake flask tests indicated that low levels of nutrients generally enhanced the number of microorganisms while supporting and stimulating the treatment process. High levels of nutrients sometimes Continued stimulated, but at other times inhibited, growth and treatment. Addition of the surfactant Tween SO sometimes stimulated treatment. Addition of the cosubstrates toluene or acetate sometimes inhibited growth slightly when used with nutrients, but inhibition was commonly offset when Tween SO was used in combination with the cosubstrates.
- Food, Food Service and Nutrition
- Ammunition and Explosives