Civil Engineering Reference
In-Depth Information
the contaminants from drinking water and concentrate them in the waste streams.
Because these processes are also commonly used to remove other nonradioactive con-
taminants, the possibility exists for these processes to concentrate significant levels of
radioactivity in waste streams, even if the treatment was not originally designed or
intended to remove radioactivity.
In addition to the waste streams containing the concentrated contaminants, some
materials used in treating drinking water will adsorb radioactive contaminants and
permanently retain them, such as sand used in filtration processes, which adsorbs and
retains radium on its surfaces. Although the radium does not interfere with the treat-
ment process, when the sand is replaced, it must be disposed of in a hazardous waste
disposal site.
At the time of this writing, the disposal of naturally occurring radioactive materials
(NORM) from drinking water treatment processes are not regulated by the federal
government. Because of the concern for the proper disposal of these wastes, in July
1990 the U.S. EPA Office of Drinking Water published ''Suggested Guidelines for the
Disposal of Drinking Water Treatment Wastes Containing Naturally-Occurring Radi-
onuclides.''
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EPA emphasizes that in most cases, state agencies with authority over
NORM wastes are the most informed sources and should be consulted. The current
methods of disposal are shown in Table 23-22.
1
The information that is presented in the following sections on radioactive liquids,
sludges, and solids disposal has been summarized from the EPA guidelines mentioned
above.
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Liquid Disposal
Discharge to Surface Waters
The NRC has established levels of radionuclides that
are allowed to be released into unrestricted areas of the environment by its licensees
(10 CFR Section 20,1302 (b)(2)(i), and Sections 20.1001-20.2401). The referenced
NRC limits are as follows: 60 pCi / L and 300 pCi / L for Ra-226 and Ra-228, and
TABLE 23-22. Summary of Current Disposal Practices of Water
Treatment Waste Containing Radionuclides
Water Type
Disposal Method
Liquids
Direct discharge to surface water
Direct discharge to sanitary sewer
Deep well injection
Irrigation
Lagooning / Evaporation ponds
Sludge
Lagooning (temporary)
Landfill disposal
•
No pretreatment
•
With prior lagooning
•
With mechanical dewatering
Land disposal
Licensed low-level radioactive waste disposal site
Solids
Landfill disposal
Licensed low-level radioactive waste disposal facility
Source:
Reference 1.
