Rehabilitation of Three Metro-North Railroad Bridges

Connecticut Department of Transportation / Metro-North Railroad

Beacon Falls and Naugatuck, CT

RED was subcontracted to remediate groundwater to facilitate the rehabilitation activities of three Metro-North bridges located in Beacon Falls and Naugatuck, Connecticut.  RED was responsible for permitting, designing, assembling and operating three mobile groundwater treatment systems.  Each treatment system was designed to remediate groundwater impacted with semi-volatile organic compounds (SVOCs) compliant to the requirements of the CT DEEP general permit for the discharge of groundwater remediation wastewater directly to surface water.


All groundwater treatment systems were operated simultaneously during construction activities.  Excavation dewatering was conducted 24 hours per day for the duration of the project and included mandatory shutdown periods while the railroad tracks were removed for bridge rehabilitation purposes.  During shutdown periods, additional labor shifts were accommodated to avoid any delay to project construction activities.

Each groundwater treatment system consisted of, at a minimum, one 21,000-gallon fractionation tank, one 10,000-gallon fractionation tank, one 2,000-pound sand filter, six trade size-2 bag filtration housings and two 1,500-pound carbon vessels.  Approximately 750,000 gallons of groundwater water was remediated and discharged to the Naugatuck River over the course of the project.


Additional activities planned for this project included the disposal of impacted soils generated during construction activities.