ENTACT implemented remedial action to address an MGP coal tar impacted ravine abutting a river in preparation for residential development.  The scope of work included excavation and stockpiling of clean overburden soils to allow installation of a sheet pile wall; installation of a dewatering and treatment system; treatment and discharge of collected groundwater; excavation, solidification, and off-site disposal or thermal processing of 10,000 tons of coal tar residuals and contaminated soil; and site backfill, grading, and restoration.  

A portion of the sheet pile wall was designed to be left in place as a cut off wall to isolate inaccessible waste materials.  Specialized steel sheets were pre-injected with a hydrophilic (VOC resistant) expanding polymer to ensure a water-tight seal. The ravine required a 24-hour dewatering effort with all surface and groundwater running through a treatment system designed to remove particulates and organics.  More than 670,000 gallons of water were treated and discharged (meeting stringent state surface water discharge parameters.  Site remediation took place concurrently with the construction of a Minor League Baseball park less than 50 yards from the project site, making odor control a critical project priority.  All work was performed under real odor monitoring without a single work stoppage due to odor exceedances.  ENTACT utilized odor suppressing foam, daily soil cover, and other Best Management Practices (BMPs) to successfully control odors.

ENTACT remediated this former MGP site located along a navigable waterway and adjacent to a residential neighborhood. The scope of work included decontamination and demolition of various above-ground structures, subsurface tar wells, gas holders, and piers; installation of sheet pile and cofferdam system to prevent failure of the riverbank and ensure the structural integrity of an on-site building during excavation at depths up to 26 ft below the river level; dewatering of excavation areas; on-site water treatment; excavation, on-site solidification, and off-site disposal of over 80,000 tons of coal tar impacted media and related MGP wastes; backfilling of excavated areas; and site restoration. Additional scope included the removal of a gas holder and associated wastes from inside a warehouse in level B PPE.