Disposal of NORM waste

NORM-containing waste is generally deposited in consolidated and over­covered piles or sludge beds, or purpose designed repositories with lined cells and protective capping [28] . As it is not feasible to move such large amounts of material, the waste tends to be disposed of on the site of its generation. Capping and some engineered structures may be used to prevent erosion and to limit the leakage of radioactive gases. In some cases, the waste has been disposed of by using it to backfill disused underground mines. There is growing evidence to suggest that bulk wastes contained in properly engineered surface reservoirs have very low radiological impacts. However, their environmental, safety and financial liability implications can be seriously underestimated. This has been demonstrated in the case of phosphogypsum stacks, where recent developments have suggested that the stacking option is not optimal and that more attention should be given to beneficial uses of the material [28]. Landfill disposal has been demonstrated as being an appropriate option for dealing with many types of NORM residue for which the quantities and activity concentrations are moderate, including most types of furnace dust with enhanced concentrations of 210Pb and 210Po. Normal landfill facilities are generally suitable, but the presence of non-radiological contaminants such as heavy metals may require the use of landfill sites specially designated for hazardous waste. NORM residues from the chemical extraction of rare earths from monazite are produced in significant quantities and have characteristically high activity concentra­tions. It has been demonstrated that such wastes can be suitably disposed of either in earthen trenches or in engineered cells, depending on the activ­ity concentration.

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