Dispersion by Chemical Reaction of Rocky Mountain Arsenal Basin F Waste Soils

摘要

Many military installations have soil contamination problems that range fromheavy metals to petroleum products. Rocky Mountain Arsenal (RMA) Basin F contains high concentrations of salts, heavy metals, ammonia, urea, and organics. The Dispersion by Chemical Reaction (DCR) process leads to a reduction in the mobility of the organic and inorganic constituents by first removing volatile constituents via steam stripping and volatilization, then trapping the nonvolatile contaminants in a nonmobile phase (microencapsulation), and finally compacting the treated material into large soil bodies (macroencapsulation). This report summarizes the results of the DCR testing of soil-amended Basin F sludge from RMA. The primary focus of this study is on pesticide leachability. The DCR process used to treat the Basin F waste soil produced a dry, homogeneous, soil-like material with desirable physical properties that on compaction achieved the following remediation goals: reduction of all leachable volatiles to nondetectable levels, confinement of all metals to below RCRA TCLP levels, and a decrease in pesticide leachability to levels approaching RCRA standards. For example, endrin TCLP concentration was reduced from 74 microgram/L to 20-28 microgram/L (regulatory limit = 20 ug/L). In several cases, reductions in pesticide leachability could be attributed to simple dilution with the calcium oxide (CaO) reagent. However in other cases, microencapsulation and/or macroencapsulation also played a role in reducing pesticide leachability. Additional work is necessary to optimize the amounts of lime-milk, hydrophobic CaO, and benign oil used in the processing of RMA Basin F waste soils. Ideally, the optimum design should achieve the regulatory and client goals, while minimizing materials handling, energy, and reagent inputs.