CONTAMINATED SOIL REMEDIATION
MARE ISLAND CRANE TEST AREA REMEDIATION
- Excavation of 15,000 cy of TPH and metal impacted soils
- On-site screening of soils
- Off-site disposal of 8,000 tons of RCRA hazardous soil
- Construction of low permeability clay cap
- Installation of new electrical utility duct bank
- Site restoration with hydroseeding and asphalt paving
Great Lakes E&I completed remedial construction activities at the Crane Test Area on the former Mare Island Naval Base in the summer of 2010. The project involved remediation of a 4 acre site known as the crane test area on at the former Mare Island Naval Station in Vallejo, CA. The scope of work included clearing and grubbing, removal of site debris, construction of a lined stockpile/screening area, excavation, screening and off-site disposal of waste soil, removal and replacement of existing site utilities, backfilling with on-site and imported soil fill, placement of a clay cap, and site restoration.
The site was subdivided into three soil excavation areas identified as the Soil Gas Area, Existing Utility Corridor, and New Utility Corridor respectively. The Soil Gas Area was divided into 4 subareas requiring a total of approximately 11,000 cy of excavation. During excavation, each bucket of soil was checked for TPH using a Flame Ionization Detector (FID). A one acre stockpile area was constructed over a 60 mil HDPE liner to facilitate screening and temporary stockpiling of excavated soils and debris. All soil containing less than 50 ppm TPH was screened to remove debris and stockpiled for reuse as backfill in the soil excavation areas. All soil containing greater than 50 ppm TPH or gross debris contamination was stockpiled separately for waste characterization and off-site disposal.
The Existing Utility Corridor was excavated to remove an abandoned electrical duct bank, miscellaneous pipelines, and surrounding soils containing elevated levels of lead. This excavation area contained 10,000 cy of soil requiring off-site disposal as California hazardous waste, RCRA hazardous waste suitable for direct disposal, and RCRA hazardous waste requiring stabilization prior to disposal. The New Utility Corridor was excavated to create a clean corridor for future utility installation. All utility excavations have been backfilled with clean, imported soil fill material.
Following completion of the excavation activities, the site was graded and capped with a minimum 3 foot layer of imported low permeability clay fill. The cap was compacted to 95 percent with final maximum permeability of 1×10-5 cm/sec. Other work included the excavation of a new joint utility trench and installation of a new electrical duct bank. The new joint utility trench and electrical duct bank was approximately 600 feet long and ran along the outside perimeter of the site under an adjacent roadway. Site restoration work included re-paving the adjacent roadway surface and hydroseeding the clay cap.