Infrastructure

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 MGP SITE IN-SITU SOLIDIFICATION AND STABILIZATION

ENTACT completed site remedial work and in-situ solidification and stabilization (ISS) of impacted soils at an eight-acre former manufactured gas plant (MGP) site. The project was located near industrial, commercial, and residential properties, as well as community parking areas, a recreational park, and water district facilities, including water supply wells. This comprehensive remediation approach ensured the effective treatment of impacted soils while safeguarding surrounding properties and community resources. On this project, ENTACT: Excavated, transported, and disposed of 52,000 tons of

ACTIVE REFINERY EXPANSION RCRA CORRECTIVE ACTION

ENTACT performed remediation activities at a Gulf Coast refinery as part of a Resource Conservation and Recovery Act (RCRA) Corrective Action to address solidified F037 waste and oily sediments in preparation for constructing a new ethane cracker unit. Scope of work completed by ENTACT: Demolished and removed at-grade and below-grade structures Removed existing cover materials for segregation, stockpiling, and/or reuse as road or laydown area material or backfill at other areas of the refinery Dewatered existing water and managed water

LNG EXPORT TERMINAL GROUND IMPROVEMENT

ENTACT performed soil improvement activities at a 1,000-acre site in preparation for the development of a liquefied natural gas (LNG) export terminal. The project site is strategically located on a ship channel with direct access to the Gulf of Mexico, offering deep-water access, proximity to abundant gas supplies, and ease of transport for buyers. ENTACT successfully completed the work within a three-month timeframe, ensuring the site was prepared for further development. Our team: Improved 410,000 cubic yards of soft saturated

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

FORMER MGP SITE

ENTACT implemented in-situ solidification and stabilization at this former manufactured gas plant (MGP) to address impacted materials and prepare the site for redevelopment. Through two phases of work, we effectively managed environmental conditions while meeting our Client’s schedule and budget objectives. Upon project completion, ENTACT had: Demolished and removed existing structures, with off-site disposal and recycling of building slabs and subsurface materials Collected, managed, treated, and discharged MGP contact water Removed, reinstalled, or protected utilities and plugged and grouted abandoned

FORMER FACTORY REMEDIATION AND REDEVELOPMENT

ENTACT successfully remediated a former factory site designated for residential and retail redevelopment, addressing contamination from multiple sources, including arsenic and lead. The property is situated in a dense urban area, divided by a city street and bordered by city transit and right-of-ways (ROWs). Upon project completion ENTACT had: Treated and disposed of 44,000 tons of non-hazardous material Stabilized and disposed of arsenic, volatile organic compound, and contaminant-impacted soils Excavated and disposed of chromium-impacted hot spot areas Utilized benching and

INDUSTRIAL COMPLEX REMEDIATION AND REDEVELOPMENT

ENTACT performed comprehensive remedial activities at a 2,200-acre industrial complex to prepare the site for mixed-use redevelopment. Leveraging our internal technical and treatability expertise, we developed a remediation solution aimed at reducing the site’s high moisture levels to meet specific objectives. This involved geotechnical evaluations, soil mixing, free draining, dewatering, and reagent assessments of source materials. To maintain an efficient schedule, we executed critical activities concurrently throughout our phased, multiyear approach. Upon project completion, ENTACT had: Removed 3.9 million cubic

FLY ASH IMPOUNDMENT CLOSURE AND DAM MODIFICATION

ENTACT undertook a multiyear phased approach for the closure of a 300-acre wet fly ash impoundment. The project commenced with the drainage of surface water, utilizing pumping and temporary drainage channels to direct water to an area behind the main dam. As surface water was managed, we excavated the exposed fly ash and relocated or regraded the surface to achieve the required subgrade elevations across the site. This careful and coordinated approach ensured effective stormwater management and successful project completion.