 |
Project Description
The Environmental Restoration Disposal Facility (ERDF) is a large CERCLA disposal facility that receives radioactive and chemically contaminated wastes from the Hanford Site. The facility originally consisted of four disposal cells.
Parsons added two more cells, bringing the total to six. Each cell measures about 500 by 500 ft at the base and is 70 ft deep. At the surface, each pair of cells measures 710 by 1,410 ft.  The cells have a double liner, a double leachate collection system, and some ancillary site work. For the leachate collection system, Parsons constructed one crest pad building for each cell to house a piping manifold and electrical controls, as well as instrumentation for the cell’s three submersible pumps (a total of six submersible pumps). Parsons also installed the piping between the manifolds and sumps at the bottom of the cells, extended the double-lined piping from the new crest pad buildings to the existing leachate collection system, and extended the existing electrical power and signal wires to the new crest pad buildings.
Earthwork consisted of excavating approximately 1 million cubic yards of soil, most of which was placed in a nearby stockpile. Approximately 140,000 cubic yards of the excavated soil was compacted at the edge of the excavation to form embankments for the new cells. A pug mill was operated to produce approximately 75,000 cubic yards of bentonite clay/soil admix. A 3-ft-thick operations layer of excavated soil was placed on top of the completed liner system. The liner system consisted of the admix layer, two 1-ft-thick gravel drainage layers, and two high-density polyethylene (HDPE) liners with associated geotextile and geomembrane layers. The primary and secondary liners each required approximately 86,000 square yards of 60-mil HDPE. The liner system was built to comply with RCRA requirements.
Ancillary site work included adding yard lighting and piping in the nearby waste transportation container queue area.
|
