Explosive biodegradation in soil slurry batch reactors amended with exogenous microorganisms

The present study explores the feasibility of biotreatment of 2,4,6-trinitr otoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)contaminate d soils in slurry batch reactors. Radiorespirometric assays showed that ana erobic sludge was able to mineralize 59% RDX to CO2 although significant mi neralization of TNT was not observed in all cases. TNT and RDX at concentra tions higher than 50 and 100 mg/L respectively were inhibitory to methanoge nesis (used as a bioindicator), however, methanogenesis recovered after TNT was transformed into less toxic triaminotoluene. Bioslurry batch reactors containing 40% of contaminated soil (2000 mg RDX and 1000 mg TNT/kS dry soi l) were operated under various conditions. Both TNT and RDX were persistent to soil indigenous microbes. Degradation of both TNT and RDX was enhanced by the municipal sludge amendment, although degradation of RDX was only ach ieved under anaerobic conditions.