Bench-Scale Investigation of Composting for Remediation of Explosives-Contaminated Soils from Iowa Army Ammunition Plant, Middletown, Iowa

Abstract : Bench-scale compost and radiolabeled studies were conducted at the U.S. Army Engineer Waterways Experiment Station (WES) and at the University of Minnesota to evaluate the reduction of explosives contaminated soil at Iowa Army Ammunition Plant. The goal of the study was to evaluate and to select the best combination of amendments, contaminated soils, and bulking agents to be utilized in the compost technology for remediation of explosives contaminated soils. The respirometric test was utilized as a screening tool to provide a general indication of biological activity within eight compost mixtures. The bench-scale compost reactor test was to extend the respirometric study by evaluating the applicability of the screened compost mixtures. The radiolabeled study was to provide insight into the apparent degradation of the explosive contaminant during the composting process. The respirometer results showed that cow manure and corn stalk (Mixture 3) and swine manure and corn stalk (Mixture 4) mixtures outperformed the other mixtures. Mixture 3 showed the best biodegradation rate; Mixture 4 showed the best respiration rate, while its biodegradation rate falls approximately within the middle of the eight treatments. Therefore, Mixtures 3 and 4 were advanced to the bench-scale composting test. The bench-scale composting study validated the explosive removal capacity of Mixtures 3 and 4. Mixture 3 temperature reached the mesophilic range (40 0C), while Mixture 4 temperature reached the thermophilic range (50 0C). The compost mixtures returned to ambient temperature after 10 days of composting.