Characterization,
Excavation, and Packaging of Laboratory Waste Disposed in
a Sewage Settling Pond at an Active University Campus
Work Description
– General:
Chase Environmental Group,
Inc. (Chase) was contracted to characterize, remediate,
and survey a facility formerly used for the disposal of
thorium contaminated laboratory debris originating from
Ames Laboratory. The characterization involved record reviews,
employee interviews, radiological surveys, and subsurface
investigation and contaminant thickness mapping and delineation,
and a final status survey using MARSSIM protocols. Subsurface
mapping involved using Chase’s GeoprobeTM and remote radiation
detectors.
Remediation involved confirmatory
surveys and excavation delineation, directional radiation
surveys to direct earthmoving equipment, sampling soils
and debris, and radiation surveys of exposed surfaces in
the excavation. Multiple hazards existed at the facility
including radiation, irregular working surfaces, open excavations,
sharp debris, and unusually high heat indices. Approximately
1,500 tons of sloping soil overburden were moved to gain
access to the contaminated material which had been deposited
in sloping layers. Nearly 900 tons of contaminated soil
and debris removed and packaged in B-25 boxes. Confirmatory
radiological analyses were performed to ensure that the
bottom of the excavation was less than required radioactivity
concentrations. Chase then backfilled the excavation with
clean soils and reshaped the slope allowing better access
to the basin portion of the training institute. Chase finalized
the Final Status survey report prepared using the MARSSIM
guidance.
Chase was contracted by the University to prepare and ship
225 bulk steel boxes of deregulated radioactive material
to a hazardous waste landfill. Using radiological and chemical
laboratory data, Chase prepared and submitted a waste profile
on behalf of the University.
Package preparation involved weighing each package, securing
box lids with steel strapping, and obscuring/removing previous
labels and markings. Additionally, intrusive package inspections
were performed by drilling a representative number of packages
and verifying the absence of liquid contents. Threaded fasteners
and sealant were used to restore package integrity. The
finished packages were loaded onto 46 separate flatbed trailers;
as many as 12 shipments were performed daily. Chase completed
Texas hazardous waste manifests and other shipping paperwork
on behalf of the University. All 46 shipments were accomplished
without incident.
Location:
Fire Service Training Institute, Iowa State University,
Ames, Iowa
Regulatory Basis:
Iowa State University Radioactive Materials License / OSHA,
MARSSIM
Contaminants: Chemical:
Petrochemical residues, unknown liquids in bottles Radiological (including isotopes and assay): Th-232
and progeny
Duration: Start 11/6/97 Stop 12/00 - Work performed in phases
with about 75 days on site.
