Skills & Services
Earthwork/Material Management
Solidification/ Stabilization
Soil Treatment
Cap and Containment System Construction
Sediment Removal
Former MGP Remediation
Residential Lot Remediation
Barrier Wall Construction
Groundwater Remediation
Wetlands Construction
Decontamination and Demolition
Water Treatment
Treatability Studies
Experience |
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 Former Manufactured Gas Plant (MGP) Remediation |
- Odor Control and Vapor Management Systems
- Enclosed, Temporary Structure Utilization
- Subsurface Structure Demolition
- Free Product Recovery
- Removal of Coal Tar Waste, Debris, and Residual Material
Project Summaries
Former MGP Site
ENTACT implemented remedial action to address a coal tar impacted ravine abutting
a river in preparation for residential redevelopment. Scope of work included
excavation and stockpiling of clean overburden soils to allow installation of
a sheeting wall; installation of a dewatering and treatment system installed
in combination with the sheet pile wall; treatment and discharge of collected
groundwater; excavation, solidification, and off-site disposal/thermal processing
of 10,000 tons of coal tar residuals and contaminated soil; and site backfill,
grading, and restoration.
ENTACT re-designed the steel sheet pile wall, which was a critical element of
the project approach, to key into bedrock as well as hard-pan glacial till (with
Toe Pins) without internal rakers allowing for greater flexibility within the
ravine. A portion of the wall was designed to be left in place as a cut off wall
for 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 particulate and organics.
In excess of 670,000 gallons of water was treated and discharged. All work was
performed during real time air monitoring activities. ENTACT utilized foam odor
suppressants, good
work practices, and daily soil cover to control odors. |
Former MGP Site
ENTACT remediated this former MGP site located along a navigable waterway and
adjacent to a residential neighborhood. Scope of work included decontamination
and demolition of various above-ground structures, subsurface tar wells,
gas holders, and pier; installation of sheet pile and cofferdam system to
prevent failure of riverbank and ensure structural integrity of an on-site
building during excavation activities at depths up to 26 feet below the river
level; dewatering of excavation areas, containment, and transport to an on-site
water treatment system; excavation, on-site solidification, and off-site
disposal of over 80,000 tons of coal tar impacted materials and MGP wastes;
and site backfilling and restoration. Additional activities included removal
of a gas holder, soils and sludges from inside a warehouse
that required level
B PPE.
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| Odor Control - Odor control at an MGP remediation site is often handled through the use of spray foam. Foam can be applied in wet or moist conditions to form a consistent encapsulating layer between contaminated materials and the environment, suppressing VOCs, dust, and odors. In addition, airtight temporary structures, equipped with air handling and cleaning equipment can be part of an integrated remediation site odor control system. |
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