Initial-phase optimization for bioremediation of munition compound-contaminated soils

Area of Science:

• Environmental Science
• Microbiology
• Soil Science

Background:

• Soils contaminated with munition compounds pose significant environmental risks.
• Bioremediation offers a sustainable approach to detoxify contaminated sites.
• Nitroaromatic compounds are persistent pollutants requiring effective degradation methods.

Purpose of the Study:

• To investigate the bioremediation of soils contaminated with 2,4,6-trinitrotoluene (TNT) and other munition compounds.
• To establish a procedure for promoting the biodegradation of nitroaromatic contaminants under anaerobic conditions.
• To identify optimal conditions for the removal of parent compounds and their intermediates.

Main Methods:

• Flooding soils with 50 mM phosphate buffer and adding starch as a carbon source.
• Incubating soils under static conditions to promote anaerobic environments via aerobic heterotrophs.
• Monitoring the degradation of TNT and its intermediates at various temperatures and pH levels.

Main Results:

• Anaerobic conditions were established within the soil cultures.
• Parent TNT molecules were removed within 4 days by anaerobic microflora.
• Reduced intermediates were removed within 24 days, completing the first stage of remediation.
• The procedure was effective between 20-37°C and optimal at pH 6.5-7.0.
• Ammonium addition improved remediation, while ammonium phosphate buffer inhibited TNT reduction.
• Polymerization of intermediates was avoided at neutral to slightly acidic pH under anaerobic conditions.

Conclusions:

• The developed procedure effectively bioremediated soils contaminated with TNT and related munition compounds.
• The process achieved complete removal of parent compounds and intermediates without forming undesirable byproducts.
• This method provides a promising strategy for the environmental cleanup of munition-contaminated sites.