Sustainable Environment

COAL-FIRED GENERATING STATION CCR POND CLOSURE ACTIVITIES

ENTACT has been engaged to perform pond closure, repurposing, and maintenance activities at this coal-fired power plant located along a major river system in the Midwest. Based on the successful completion of the East Bottom Ash Pond Closure, ENTACT was awarded additional work at the facility, as outlined below, on a competitive or sole-sourced basis. Highlighted projects include: West & East Bottom Ash Pond Repurposing, & Wastewater Pond Sediment Removal: The West Bottom Ash Pond (WBAP) is being closed by

FORMER MINE SITE PROCESS AREA RADIOLOGICAL REMEDIATION

ENTACT was engaged to perform comprehensive radiological remediation at a former copper mine site in the Rocky Mountains. This project involved the removal of radiologically impacted soil, asbestos pipe, and the capping of tailings in former evaporation ponds. All actions were executed in compliance with an EPA Administrative Order on Consent, ahead of schedule, and with a strong emphasis on worker health and safety, which impressed the EPA. The project included the following key activities: Evaporation Pond Closures: To facilitate

FORMER WOOD TREATING SITE CORRECTIVE MEASURES

ENTACT implemented corrective measures at a 52-acre former wood-treating facility that produced creosote-treated railroad crossties. This comprehensive remediation project aimed to contain contamination and restore the site for future use. For this project, ENTACT: Installed a 2,200 linear foot soil-bentonite slurry wall to a depth of 45 feet below surface grade to contain the source area and control groundwater migration Excavated and consolidated 17,000 cubic yards of polycyclic aromatic hydrocarbon and phenol-impacted surface soils, subsurface soils, and sediments Dewatered and

PICKLE POND REMEDIATION AND HABITAT CONSTRUCTION

White Lake Dock & Dredge, a division of ENTACT, performed remedial activities at Pickle Pond, a nine-acre urban pond situated in the St. Louis River lower estuary. This project aimed to enhance the habitat for local wildlife, including waterfowl, beavers, and otters, while addressing sediment contamination. During this project, our team: Dredged more than 16,000 cubic yards of contaminated sediments composed of fine-grained silty clays Solidified dredged materials by applying a non-toxic super absorbent polymer to reduce excess water, allowing

FORMER CHROMIUM ALLOY AND RADIOLOGICAL SUPERFUND SITE

ENTACT executed a four-phased remedial action project to support the decommissioning of a former glass and super alloy additives manufacturing facility. The site, due to historical metallurgical operations, exhibited metals and radiological contamination in soil and sediment both on-site and in adjacent areas, including wetlands, a stream channel, and wooded uplands. The project phases were designed to systematically address the impacted materials, as outlined below: Phases 1 and 2 Remediation: The initial phases focused on materials within the property limits.

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

CHEMICAL AND RADIOLOGICAL REMEDIATION

ENTACT is leading an extensive ecological restoration of more than 100 acres at a former industrial site that hosts several chemical manufacturers, a clay mining operation, and a disposal area for impacted soils and dredge spoils. The restoration plan aims to create a 14-acre open-water pond, 40 acres of wetland mitigation, 55 acres of upland enhancement, and nearly two miles of public walking trails and boardwalks. The project comprises multiple phases, detailed below: Phase 1: Sediment Remediation The initial phase

ACTIVE STEEL MILL CREEK AND DITCH PCB SEDIMENT REMOVAL

ENTACT partnered with our Client to implement a phased solution for the removal of PCB-impacted sediment and the restoration of the surrounding river and its environment for the benefit of the nearby community. The project involved comprehensive remediation efforts across 3,000 linear feet of ditch line and 5,600 linear feet of creek channel. ENTACT performed the following scope activities: Transported 178,500 tons of PCB-impacted sediment, clay, and native materials off-site for disposal Treated and filtered four billion gallons of water

FORMER PHOSPHATE FERTILIZER SITES REMOVAL ACTION

ENTACT executed comprehensive remediation efforts across nine former phosphate fertilizer production and manufacturing sites to address lead- and arsenic-impacted soils, sediments, and groundwater. Partnering closely with our Client, ENTACT navigated the complexities and regulatory requirements of this multifaceted remediation project. The sites were in commercial, residential, and industrial zones, with tidally influenced areas adjacent to navigable waterways, marshes, uplands, active rail lines, and major highways. While the scope varied across the sites, the typical activities included: Excavation and off-site disposal

AGGREGATE MINER AND SUPPLIER SLURRY WALL PROGRAM

ENTACT initially served this major aggregate miner and supplier by replacing a cutoff wall more than 9,000 feet high. This successful project established ENTACT as the Client’s dedicated slurry wall contractor. Building on that relationship, we constructed a bentonite slurry wall to minimize dewatering efforts and facilitate dry mining operations. This collaborative effort ensured minimal disruption to mining operations while effectively managing groundwater. On this project, ENTACT: Constructed a 7,438-foot-long, 30-inch-wide soil-bentonite slurry wall Identified and protected subsurface utility lines

TAR PONDS AND COKE OVENS SITE SOLIDIFICATION AND STABILIZATION

The tar ponds at this site were filled with waste from a steel mill and coke oven, which significantly impacted the nearby tidal estuary with contaminated sediments and sludge. In response, the governments of Canada and Nova Scotia initiated a cleanup plan to remediate the site and create Open Hearth Park, a community gathering space. ENTACT played a pivotal role in this project by developing solidification and stabilization mix designs in our treatability lab and validating the recommended formula through

WET ASH IMPOUNDMENT CLOSURE

ENTACT successfully completed the closure of a 140-acre wet fly ash impoundment containing 13.4 million cubic yards of coal combustion residual (CCR). The project involved a comprehensive approach to manage surface water by pumping and utilizing temporary drainage channels in the deposited ash, directing it to a permitted outfall located behind the main dam. Notable scope items on this project completed by ENTACT: Lowered the main dam and removed the saddle dam Constructed a new spillway for both dams to

INTEGRATED ENERGY COMPANY KEY SUPPLIER PROGRAM

ENTACT has been a trusted partner for a major integrated energy company, performing remedial construction, geotechnical construction, and civil construction activities throughout the U.S. and select international locations for more than 20 years. This longstanding relationship underscores our commitment to collaboration and excellence. We work closely with the Client’s team during the planning phase, assisting with preliminary design evaluations, site engineering, remedy selection, and cost budgeting for various projects. Our services focus on delivering safe, effective, and cost-sensitive solutions at