Excavation

excavation

Completion Date: May 2016

The Plan

Handex completed required remediation work for the construction of a new 50,000 square foot service plaza that was designed to be built atop an old fueling facility. In 2008, early in the planning for this site, two public sector entities, with the support of Handex, agreed that a source removal effort would be wise to allow for cost effective and quick site remediation in the future. A source removal would also prevent the possibility of vapor intrusion into the new plaza facility. As a result of this planning, the clients agreed that the source soil located under the new location should be removed prior to construction.

The Work

The schedule to complete the project was very tight and allowed very little time for this source removal effort. The work was scheduled to start and be completed between the old fuel facility removal and construction of the new service area. The schedule allowed a 40 working day window to complete the project. Handex worked with all parties involved and spent considerable time pre-planning the schedule. The plan included all of the details associated with dewatering system installation, water treatment system operation and maintenance (O&M), excavation layout plan, backfill plan, truck routes, utility layout, and every other aspect of the work, all the way down to air monitoring points to ensure the traveling public and Handex employees were not exposed to any petroleum vapors.

Handex started the project by installing well points around the eastern half of the excavation and immediately began dewatering and water treatment activities, along with the required discharge monitoring. Site entry and exit points were installed to eliminate the tracking of sediments into the road. Excavation began in the northeast corner and progressed southward. Once approximately one third of the excavation was completed, Handex began backfilling the excavation with approved fill material and compacted the material to 100% of the standard Proctor. After two truckloads of backfill were placed, Handex placed Oxygen Release Compound (ORC) to expedite future groundwater remediation. The backfill was then completed to grade. Once placement of backfill was above the natural groundwater elevation, Handex installed the dewatering system around the west excavation area and disabled the east dewatering system. Excavation of the west area began and backfilling of the east side was completed. Upon completion of all excavation and backfill work, Handex demobilized all of our equipment and resources.

The Result

The job was completed within the 40 working day window. Handex excavated and disposed of 42,773 tons of contaminated soil, placed 53,139 tons of clean backfill material, and treated and discharged 13,500,000 gallons of groundwater.