As part of a major petroleum hydrocarbon remediation at a former bulk terminal and distribution facility, ENTACT installed a perimeter dewatering and treatment system. Excavation depths of up to 21 below grade, in conjunction with the site’s close proximity to the Bay, necessitated the installation of a perimeter dewatering system (comprised of sixty-four (64) temporary dewatering wells and six (6) mobile sumps) to minimize ground water infiltration. A portable water treatment system was used to treat recovered water bearing suspended solids and petroleum hydrocarbons at rates of up to 1,000 gallons per minute. By project completion, over 48 million gallons of water had been collected, treated and discharged to the sanitary sewer.
Additional scope included excavation, stockpiling, and off site disposal of more than 205,000 tons of petroleum impacted soils via rail gondolas. Additional work scope included the excavation, stockpiling and reuse of over 75,000 cubic yards of overburden; on-site crushing and reuse of more than 30,000 tons of concrete; demolition of 75,000 square ft of on-site structures; installation of an 8-inch water line; cleaning and removal or in-place abandonment of site wide underground piping (including 5 miles of piping beneath city streets); management of recovered petroleum products; restoration of city streets; and final site backfill and restoration.
Project scope included the excavation, staging, transportation and disposal of 800,000 tons of PCB impacted materials and total material handling of over 1,200,000 tons. ENTACT was additionally responsible for the construction of a 40-acre onsite waste repository. Other remediation activities included the complete excavation and restoration of stormwater conveyance channels from the plant; construction of haul roads to enable access/egress to and from the removal areas; the construction of staging areas ranging in size from 3.5 acres to 6.5 acres to expedite loading and transportation of impacted material; and the construction of 2 miles of diversion channels to enable sediment removal from the creek bed and flood plain.
Water management was a 24-7 activity that included containment and treatment of millions of gallons of contact water encountered in the impacted areas. A pair of 1,000 gpm water treatment systems were designed, installed, and simultaneously operated by ENTACT. The systems were comprised of an interconnected series of ten or more baffled settling tanks (20,000 gallons), skimmer removal of free product, polymer injection to enhance settling, solids filtration using sand and bag filters; and removal of dissolved organics via carbon adsorption units.