Groundwater, explosive contamination

A site-specific, cost-benefit analysis is required to determine if an active remediation system or MNA would be the most effective remediation option (D11322U, p. 8). In 1999, the U.S. Army prepared an analysis of the cost of MNA, in situ bioremediation, and pump-and-treat systems for the treatment of explosives-contaminated groundwater at the Louisiana Army Ammunition Plant in Min den, Louisiana (D22026Y). This comparison is summarized in Table 1. 

GAC can be used to treat explosives-contaminated water, including process waters from the manufacture and demilitarization of munitions (pink water) and groundwater contaminated from disposal of these process waters. GAC is not used to treat red water produced during the manufacture of TNT. 

The migration of explosives from surface soil to the water table is governed by their physicochemical properties and the mechanisms of their interaction with the soil matrix (mainly clay, and soil organic matter). The frequent detection of TNT (S = 140 mg/L) and RDX (S = 45 mg/L) in groundwater of contaminated sites is confirmed. As for HMX, its limited solubility in water (<5 mg/L) restricts its presence close to the soil surface. No field data is yet available on CL-20. 

Bams PW, Heaston MS. (2001). Treatment of explosive-contaminated groundwater by in situ cometabolic reduction. In Bioremediation of Energetics, Phenolics, and Polycyclic Aromatic Hydrocarbons (eds. VS Magar, G Johnson, SK Ong, A Leeson). Columbus, OH BatteUe, pp. 25-33. 

This section deals with the unique properties of explosive contamination. Most explosives are toxic, particularly in drinking water. The older the site, the more explosive residue will enter the groundwater. Even explosives... 

Montemagno, C. D. 1991. Evaluation of the feasibility of biodegrading explosives-contaminated soils and groundwater at the Newport Army Ammunition Plant (NAAP). USATHAMA Report CETHA-TS-CR-9200. Argonne National Laboratory, Chicago. 

The cost of pretreating contaminated groundwater on site, for discharge to a publicly owned treatment works is often the preferred alternative (provided the facility has the capacity and local regulations allow acceptance). Pretreatment is usually required to prevent explosive vapors in the sewers and disruption of the biological treatment at the plant. The most common pretreatment includes phase separation and reduction of dissolved contaminants to an assured safe concentration. At small sites, it is not unusual to use phase separation, air stripping, and activated charcoal filtration prior to discharge to a sanitary sewer. 

Constructed wetlands are engineered systems designed to mimic the physical, chemical, and biological mechanisms of a natural wetland. Wetlands may be constructed above ground to resemble natural wetlands such as swamps, bogs, and marshes or they may treat contaminated water below the surface. Constructed wetlands have been used for the ex situ treatment of groundwater contaminated with explosives. 

The regional temperature variations, rainfall, patterns, groundwater flow characteristics, explosive type, explosive concentration, presence of other contaminants, land value, and other regulatory requirements can affect the wetland s cost. Constructed wetlands may not be financially viable at aU sites (D20499J, p. 2 D20503Y, p. 30). 

The costs of a 10-acre, full-scale, gravel-based constructed wetland used to teat groundwater contaminated with explosive compounds were calculated based on the field demonstration at the U.S. Department of Defense s (DOD s) Milan Army Ammunition Plant near Milan, Tennessee. The estimated, site-specific costs of a 200-gal/min system that discharges effluent to surface waters were 3,466,000 in 1998 dollars. Amortization of these costs was estimated at 1.36 per 1000 gal of effluent for 10 years and 0.45 per 1000 gal for 30 years. Table 1 shows a breakdown of the site-specific estimate. Capital costs for a similar system with groundwater... 

Molasses has been used as a nutrient source to encourage the anaerobic bioremediation of soil and groundwater contaminated with metals, explosives, and chlorinated solvents. The nutrient source can be added to excavated, screened soil, or injected directly into the subsurface via wells. Several vendors and developers have conducted bench-, pilot-, and full-scale demonstrations of the technology. Some of the molasses technologies are commercially available. 

Natural attenuation, often called intrinsic remediation, intrinsic bioremediation, bioattenuation, or monitored natural attenuation (MNA) is an in situ treatment technology for soil, sediment, or groundwater. The technology has been used for full-scale remediation of sites contaminated with volatile organic compounds (VOCs), total petroleum hydrocarbons (TPH), chlorinated solvents, explosives, inorganics, and metals. 

Levy, H. B., "On Evaluating the Hazards of Groundwater Contamination by Radioactivity from an Underground Nuclear Explosion," Lawrence Livermore Laboratory, Rept. UCRL-51278, (September 18, 1972). 

Contamination by nitroaromatic compounds, especially TNT, stems primarily from military activities (Boopathy et al., 1994). During the manufacture of explosives and the disposal of old munitions, large quantities of water became contaminated. This wash water was typically disposed of in unlined lagoons that facilitated the slow release of the explosives from the soil in the lagoons into groundwater, lakes, and rivers. 

Melting explosive octahydro-l,3,5.7-tetranitro-l,3,5,7-tetrazocine) and i N-dimethylhydrazine. These compounds are sometimes present at quite high levels in soils and groundwater on military bases and production sites. Bioremediation is a promising new technology for treating sites contaminated with such compounds. 

Zappi, M.E., Hong, A., and Cerar, R., Treatment of groundwater contaminated with high levels of explosives using traditional and non-traditional advanced oxidation processes, HMCRI Superfund Conf, Washington D.C., 1993. 

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