Environmental Remediation

FORMER MINE SITE PROCESS AREA RADIOLOGICAL REMEDIATION

ENTACT conducted three remedial actions at a former copper mine site in Nevada. The remediation required the removal of 6,000 tons of radiological soil, 21,000 feet of “transite” asbestos pipe, and the capping of 25 acres of tailings in two former evaporation ponds. All actions were completed in compliance with an EPA Administrative Order on Consent, ahead of schedule, and with no injuries to onsite personnel. The EPA “was particularly impressed by the strong emphasis placed on worker health and safety throughout the project.”

FORMER MGP SITE IN-SITU SOLIDIFICATION AND STABILIZATION

ENTACT completed site remedial work and in-situ solidification and stabilization (ISS) of impacted soils at an 8-acre former manufactured gas plant (MGP) site. The project was situated near industrial, commercial, and residential properties; community parking areas, a recreational park; and water district facilities, including water supply wells. Remediation included excavation, transportation, and disposal of 52,000 tons of MGP-impacted soils; in-situ solidification and stabilization of approximately 168,000 cubic yards of impacted material using cement-bentonite-slag grout; construction of a temporary containment structure

PICKLE POND REMEDIAL AND HABITAT CONSTRUCTION

Pickle Pond is a nine-acre urban pond created by the construction of a railroad embankment that cut off part of Barker’s Bay. The pond is in the St. Louis River lower estuary, sheltered from the main bay, and provides habitat to waterfowl, beavers, otters, and other wildlife. White Lake Dock & Dredge, Inc., a division of ENTACT, LLC, was responsible for dredging more than 16,000 cubic yards of contaminated sediments consisting of fine-grained silty clays from a shallow draft area

FORMER CHROMIUM ALLOY AND RADIOLOGICAL SUPERFUND SITE

ENTACT was engaged to perform a four-phased remedial action project to support the decommissioning of this former glass and super alloy additives manufacturing facility. Due to historical and metallurgical operations conducted at the site, metals and radiological impacts were present in soil and sediment on the property and off-site, consisting of wetlands, a stream channel, and wooded upland areas. Phase 1 of the project addressed the impacted materials on the property limits, and Phases 2, 3, and 4 addressed the

Aerial view of an active project site with water, bridges and buildings in the background

CHEMICAL AND RADIOLOGICAL REMEDIATION

ENTACT is performing an ecological restoration of 100+ acres previously home to several chemical manufacturers, a clay mining operation, and a disposal area for impacted soils and dredge spoils. The restoration plan includes creating a 14-acre open-water pond, 40 acres of wetland mitigation, 55 acres of upland enhancement, and close to two miles of public walking trails and boardwalks. The first phase remediated impacted sediments from a 4.9-acre lake on the site. Benzaldehyde, bis (2-ethylhexyl) phthalate (BEHP), formaldehyde, and PCB

ACTIVE STEEL MILL CREEK AND DITCH PCB SEDIMENT REMOVAL

ENTACT partnered with our Client to implement a phased solution to remove the impacted sediment and restore the river and its surroundings for a nearby community. Work included remediating 3,000 linear feet of ditch line and 5,600 linear feet of creek channel; transporting 178,500 tons of polychlorinated biphenyl-impacted sediment, clay, and native materials off-site for disposal; and treating and filtering 4 billion gallons of water using an onsite water treatment system. In addition to meeting our Client’s objectives, we managed

FORMER PHOSPHATE FERTILIZER SITES REMOVAL ACTION

ENTACT performed remediation of nine former phosphate fertilizer production and manufacturing sites to address lead- and arsenic-impacted soils, sediment, and groundwater. ENTACT partnered with our Client to navigate the complexities and requirements of this multi-facet remediation project. Sites were in commercial, residential, and industrial zones. Tidally influenced areas were located adjacent to navigable waterways, marshes, uplands, and active rail lines and major highways. While scopes varied in magnitude at each site, work typically involved excavation and off-site disposal activities, sediment

TAR PONDS AND COKE OVENS SITE SOLIDIFICATION AND STABILIZATION

The tar ponds were filled with waste from a steel mill and coke oven, transforming the nearby tidal estuary with impacted sediments and sludge. The governments of Canada and Nova Scotia announced a plan to clean up the site and establish Open Hearth Park, a community gathering place. ENTACT developed solidification and stabilization mix designs in our treatability lab and confirmed the recommended formula through a successful field pilot program. We solidified and stabilized approximately 745,000 cubic yards of impacted

WET ASH IMPOUNDMENT CLOSURE

ENTACT completed the closure of a 140-acre wet fly ash impoundment containing approximately 13.4 million cubic yards of coal combustion residual (CCR). The project required draining the surface water via pumping and temporary drainage channels in the deposited ash and directing it to an area behind the main dam where a permitted outfall was located. The overall scope of work for the project involved lowering the main dam, removing the saddle dam, and constructing a new spillway for both dams;

PCB SITE RESIDENTIAL REMEDIATION AND RESTORATION

This active industrial facility’s surrounding area contained polychlorinated biphenyls (PCBs) that needed to be removed because of nearby residential and community spaces. ENTACT used its residential remediation expertise to develop a field approach that prioritized the community’s safety, communication with the impacted neighbors, and an efficient schedule to complete this multiyear remediation and restoration project. Site activities included remediation and restoration of 676 PCB-impacted residential properties; transportation and placement of removal soils to either an onsite staging area or an

INTEGRATED ENERGY COMPANY KEY SUPPLIER PROGRAM

ENTACT regularly performs remedial construction, geotechnical construction, and civil construction activities throughout the U.S. and select international locations for a major integrated energy company. Our 20+ year relationship demonstrates our commitment and partnership to our Client. We work with the Client’s team, assisting with preliminary design evaluations, site engineering, remedy selection, and cost budgeting in the planning phase of its many projects. We perform safe, effective, and cost-sensitive solutions at active and closed refineries, terminals, retail sites, oil field production

FORMER MGP SITE

ENTACT implemented in-situ solidification and stabilization at this former manufactured gas plant (MGP) to address the impacted materials. Through two phases of work, we successfully managed environmental conditions and prepared the site for redevelopment, while meeting our Client’s schedule and budget objectives. ENTACT performed various activities, including demolition and removal, off-site disposal and recycling of building slabs and subsurface structures. We performed collection, management, treatment and discharge of MGP contact water; removal, reinstallation or protection of utilities; plugging and grouting