Scrap metals, contaminated

Substantial quantities of aluminum, copper, and steel are reused as scrap. The challenge is to purify the scrap metal sufficiently to process it for reuse. There is opportunity for new processes that can remove unwanted elements—either alloyed or piece contaminants—more effectively and at lower cost than current processes. 

U.S. EPA, Contaminated Scrap Metal, U.S. Environmental Protection Agency, Washington, DC, July 2008. Available at http //www.epa.gov/rpdwebOO/source-reduction-management/scrapmetal.html... 

An application well-suited for IMS is the decommissioning and cleanup of sites where extensive manufacturing of explosives has taken place in the last century and where widespread contamination of soils and waters has occurred [74]. Decontamination of model metal scrap artificially contaminated with TNT and of decommissioned mortar rounds stiU containing explosives residue was followed by sampling surfaces with analysis by a portable mobility spectrometer. Mixed anaerobic microbial populations of bioslurries were employed in decontamination of scrap and the mortar rounds, and the IMS analyzer was seen as a sensitive field... 

In 1997, the U.S. Department of Energy (DOE) released bench-scale results of an integrated TechXtract system for decontaminating surfaces contaminated with radionuclides. The overall economics of the system were evaluated. Costs for the system compared favorably with existing options for radioactively contaminated scrap metal (D177859, p. 3). 

The first part of the following analysis considers the toxic metals in this waste and evaluates the waste for near-surface disposal. In a second part of this example, the waste is presumed to be contaminated by 137Cs from sources inadvertently included in scrap metals that are recycled into the manufacturing process. 

Similarly, PBCDF agent-contaminated scrap metal that has been thermally decontaminated and further cleaned to remove loose residue may be managed as a hazardous waste and disposed of at a permitted RCRA TSDF or, alternatively, managed as scrap metal and recycled exclusively by smelting (ADEQ, 2006). 

NECDF metal waste consists primarily of empty TCs. As of December 2006, a total of 272 TCs out of 1,690 had been processed through the TC thermal decontamination unit. Empty TCs are heated to 1000°F in this unit, which produces decontamination equivalent to the Army designation 5X (agent free or decontaminated potentially agent-contaminated waste). TCs decontaminated to this level at NECDF are routinely recycled to metal processors as scrap metal for smelting and reprocessing. 

The three most voluminous closure wastes at the incineration sites are metals, spent activated carbon, and rubble or debris. Of these, contaminated metal is probably the easiest to manage as it will most probably be cut up and put through the metal parts furnace for decontamination and disposal. Provisions for recycling treated scrap metal have already been included in the RCRA permits for each site. A review is needed prior to closure to ensure that scrap metal from closure operations can be handled in the same fashion and that proper analytical and on-site decontamination procedures are in place to clear the metal for shipment. 

Contaminated Scrap Contaminated, empty drums were shredded using a transportable metal shredder, packaged in cardboard boxes and fed into the incinerator via the solids feed system. The clean metal recovered from the ash discharge system was sold to a foundry and melted down into recyclable metal feedstock. Most of the scrap metal processing occurred during the warmer months. 

Mustard and contaminated scrap were incinerated out over a ten month period following approval of the test bums. During this time, the system availability averaged 55%, well below the industry average of 70 to 75% for solid waste incinerators. The prime cause was the need to perform frequent repairs to the refractory lining as a result of abrasion and impacts from the scrap metal feedstock. When operating, the system capably maintained stack emissions well within project limits and no stack excursions occurred while processing bulk mustard. 

The TC-60 TDC produces moderate amounts of secondary waste, which might or might not contain contaminants at concentrations of regulatory concern. The scrap metal is thermally decontaminated (to <1VSL) before it is removed from the detonation chamber. 

Offgases from the SDC2000 are up to 150 Nm /hr of nitrogen, water vapor, and carbon dioxide. The acidic and basic scrubbers would produce no liquid effluents but would produce up to 500 lb per day of salts as a filter cake, which would need to be tested for contaminants of regulatory concern. The scrap metal resulting from the munition bodies is suitable for unrestricted release however, this waste is a listed waste in Kentucky and can therefore be sent only to a... 

The solid wastes are primarily scrap metal from destruction of the munition bodies, bursters, and fuzes. The release level for this material is <1VSE. If problems arise with residual mustard contamination in the scrap metal, the metal could be decontaminated by thermal treatment in the main plant. 

Because of their metallic housings, sources can get mixed in with scrap metal and pass undetected into scrap metal recycling facilities. If melted in a mill, they can contaminate die entire batch of metal and die larger facility, costing millions of dollars in lost productivity and cleanup costs. The scrap industry uses radiation detectors to screen incoming material. However, sources that are under large loads may be undetected initially. 

State and local governments must realize at the outset that the military lacks experience in many aspects of environmental remediation and even in munitions clearance. For example, until 1994 there was a moratorium on the excavation of chemical weapons. UXO technicians may also be unfamiliar with residual contamination from chemical and explosive weapons. Even with explosive ordnance, mistakes can occur. Recently a scrap metal worker was killed when an ordnance item that was hidden among other ordnance scrap metal exploded while being cut up for scrap with a torch. Another area where the military lacks ordnance experience is in World War I and older ordnance and in experimental ordnance. The database of the U.S. Army Engineering and Support Center in Huntsville, Alabama, is often incomplete in these areas. 

Most halogenated polyphenyls in transportation, then, derive not from product shipments but from decommissioned equipment, drained fluids, soils and debris from waste site and riverbed cleanups, demolition work, scrap metal disposal, contaminated textiles and absorbents, and other wastes. 

Exposure to toxic chemicals by injection does not occur frequently in the chemical laboratory. However, it can occur inadvertently through mechanical injury from "sharps" such as glass or metal contaminated with chemicals or when chemicals are handled with syringes. The intravenous route of administration is especially dangwous because it introduces the toxicant directly into the bloodstream, eliminating the process of absorption. Nonlaboratory personnel, such as custodial workers or waste handla-s, must be protected from this form of exposure by putting aU "sharps" in special trash containers and never in the ordinary scrap baskets. Hypodermic needles with blunt ends are available for laboratory use. 

Mr. Petr discussed the source term foimd in mining wastes, as a function of components of the U-238 decay chain and the relative equilibrium between U-238, Ra-226, and the contribution from the Th-232 series. Contaminated items (e.g., scrap metals) can be characterised by using approximate mass to surface specific activity ratios. 

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