Environmental Engineering Reference
In-Depth Information
was noticeable, but not at high enough levels to constitute an occupational or local
environmental hazard. After all of the waste was treated, final sampling done, and
compliance testing completed and approved by the state, the solid was excavated
and moved to the final disposal site. The treatment site was then graded and subse-
quently used for plant expansion. Operational parameters for the project follow:
Volume Treated:
4,000,000 gallons (19,800 yd 3 )
Treatment Rate:
130,000 GPD average
Time:
Spring 1976
Treatment Cost:
$0.167/gallon
Disposal Method:
Sanitary landfill, daily cover material
13.4.3.5
QC and Results
Frequent initial sampling and testing were done on the first 100,000 gallons of waste
treated to verify that the process was operating as planned. Thereafter, samples were
collected from the process stream at intervals of approximately every 1000 yd 3 of
waste treated. In addition, samples were taken from the completed waste pile and
shared with the state. Final approval was given and the treated product was removed
from the site.
13.4.4
C ASE S TUDY #4: R ADIOACTIVE W ASTE S TABILIZATION AT
THE U.S. D EPARTMENT OF E NERGY S AVANNAH R IVER S ITE
13.4.4.1
Background and Purpose
Stabilization technology is used to treat radioactive wastes generated at several
facilities owned by the U.S. Department of Energy (DOE). Two examples — Salt-
stone and “empty” tank fills — from the Savannah River Site (SRS) are provided
below. The treatment objectives for waste and environmental media contaminated
with radionuclides include chemical treatment or microencapsulation to reduce the
mobility of selected contaminants of concern (COCs), solidification of an aqueous
phase, or physical stabilization of wastes to minimize the potential for landfill
subsidence. The COCs are typically radioactive isotopes, soluble salts, chemicals or
metals carrying RCRA hazardous codes, or other constituents that must be managed
to meet maximum concentration limits (MCL) drinking water concentrations in the
disposal landfill. Waste that contain both radioactive and RCRA hazardous contam-
inants is referred to as mixed waste and is regulated by either DOE (defense related)
or NRC (commercial nuclear) and EPA, respectively. Most of the radioactive wastes
identified for stabilization treatment are aqueous-based liquids or sludges (mixtures
of soluble and insoluble solids plus water). However, fine particulates, debris (pro-
cessing equipment and construction materials), environmental media (soils and
debris associated with old disposal sites), or contaminated structures that are iden-
tified for in situ closure may also require stabilization treatment in order to meet the
requirements for disposal. In all of these applications, stabilization is intended to
provide a chemical environment that will reduce leaching when in contact with water
and to bind the particles together and thereby reduce the potential for spread of
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