Field Demonstration of Slurry Reactor Biotreatment of Explosives-ContaminatedSoils

摘要

Bioslurry technology requires excavation and screening of soil to remove rocks,mixing soil with water to form a slurry, mixing the slurry in a reactor, and removal of the slurry from the reactor. Biodegradation of explosives also requires a co-substrate (e.g., molasses), pH > 6, and aerobic-anoxic operation. In this study, the native microbial population degraded explosives in soil. Four reactors (350-380 gal) were operated at the Joliet Army Ammunition Plant: a control with no co-substrate, 20% and 10% weekly replacement (by volume) reactors, and a 5% daily replacement reactor. This design allowed investigation of different soil (and therefore TNT 2,4,6-trinitrotoluene) loading rates. The target soil slurry was 15% (weight/weight). Explosives concentrations in soil were 2,000-8,000 mg/kg. Environmental conditions were identical for all reactors, and temperature, pH, and dissolved oxygen were similar. This demonstration showed that the important process parameters for successful (>99%) removal of TNT are an organic co-substrate (molasses), operation in an aerobic-anoxic sequence, and temperature. Cold temperatures slowed the rate of microbial metabolism. The demonstration successfully removed explosives and microbial intermediates from the soil. In summary, the bioslurry system has a real potential to degrade explosives, particularly TNT, from soil.