Environmental Engineering Reference
In-Depth Information
treatment technology, there still exists a small percentage of commercial mixed waste
for which no treatment or disposal capacity is available. Commercial mixed waste
volumes are very small (approximately 2%) compared to the total volume of mixed
waste being generated or stored by DOE.
As mandated by the Federal Facilities Compliance Act (FFCA), which was
signed into law on October 6, 1992, DOE has developed Site Treatment Plans to
handle its mixed wastes under the review of EPA or its authorized States. These are
being implemented by orders issued by EPA or the state regulatory authority. It will
take the cooperation of DOE, EPA, NRC, and the states to manage treatment, storage
and disposal of mixed waste.
3.4.2
M
IXED
W
ASTE
C
HARACTERIZATION
Proper characterization of mixed waste is extremely important and encompasses all
of the challenges of both radioactive waste characterization and hazardous waste
characterization.
Mixed waste is a waste material that contains radioisotopes and possesses other
hazardous properties; i.e., the waste is (1) ignitable or explosive; (2) toxic; (3)
corrosive (pH greater than 12.5 or less than 2); (4) reactive; (5) persistent (haloge-
nated hydrocarbons and polycyclic aromatic hydrocarbons with more than three and
less than seven rings); or (6) carcinogenic.
A waste is mixed if it is classified by federal agencies as being both radioactive
and hazardous. At Berkeley Lab, a waste is characterized as radioactive if either
process knowledge or monitoring and sampling show that radioactive material has
been added to the waste through DOE research or support activities.
•
Hazardous wastes containing naturally occurring radioactive material as
the sole radioactive constituent are disposed of as mixed waste only if
they have been isotopically enriched during research or support activities.
For example, photographic fixers and other hazardous materials contain-
ing only
40
K in its naturally occurring isotopic abundance are managed
for hazardous characteristics.
•
Hazardous wastes containing only isotopes with half-lives shorter than 7
hours (e.g.,
18
F) may be decayed for 10 or more half-lives in generator
areas, surveyed to confirm activity level indistinguishable from back-
ground, and managed as hazardous waste.
•
Hazardous wastes containing isotopes with half-lives greater than 7 hours
and no more than 90 days (e.g.,
32
P,
35
S,
125
I, etc.) must be managed as
mixed waste in generator areas. After transfer to the Hazardous Waste
Handling Facility (HWHF), such waste is decayed through 10 or more
half-lives, surveyed or sampled to confirm low activity, and disposed of
as hazardous waste.
•
Hazardous scintillation fluids with activities less than 0.05 μCi/g due
solely to
3
H and/or
14
C are managed as mixed waste in generator areas.
After the waste is transferred to the HWHF and the composition is con-
firmed, the waste may be managed as nonradioactive.
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