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In the Field: Former Rail Site Remediation and Wetland Restoration
Contracted to perform remediation and restoration of two delineated wetland areas on the premises of an industrial facility, totaling one and a half acres.Byline: BTB Editor
April 30, 2023 / Time to read: 5 minHistoric operations at a rail testing site in Danbury, Connecticut left the surrounding wetland soils contaminated with PCBs, petroleum compounds and metals. US Ecology was contracted to perform remediation and restoration of two delineated wetland areas on the premises of the industrial facility, totaling one and a half acres. Sampling and laboratory analysis of the contaminated soil identified that more than half of the contaminated soil reached PCB contamination levels, falling under TSCA regulation, deeming it hazardous material. Before work could begin, US Ecology’s remediation experts developed an innovative project execution plan and acquired the proper permits.
As an initial step, our crew, consisting of OSHA 40-hour trained team members, dewatered the areas and treated approximately 600,000 gallons of water prior to discharge to the local POTW.
Two acres of wetland and upland areas at the site required clearing and grubbing prior to installation of erosion control measures. Surface water control was achieved with diversion features and Tidewall® sheeting, and groundwater infiltration was managed via strategic placement of a sump pump.
Our crew performed hot spot soil removal underneath concrete floors and replaced the soil with new material. The remaining structures on the premises were demolished and we managed the identification, handling and packaging of suspected asbestos-containing materials for disposal. We implemented air monitoring measures and performed decontamination and compliance sampling in accordance with TSCA criteria. In total, we excavated approximately 4,200 tons of contaminated soil and replaced it with new topsoil specifically blended for wetland rehabilitation. We chose material that exceeds normal backfill requirements, meeting site-specific ecological risk standards. The existing stormwater collection network and hydrodynamic separator, including 2,500 linear feet of pipe of varying sizes, were thoroughly cleaned and we safely disposed of the sediments.
The final step for this remediation was to carefully reconstruct and rehabilitate the wetland areas to restore them to their natural function. Restoration measures consisted of microtopography contouring of the backfilled areas, application of customized design mixes of wetland and upland seed mixes and installation of biodegradable matting.
All impacted materials were removed and transported for disposal at approved licensed facilities. Despite significant weather obstacles, including heavy rain, the project was completed safely and on schedule.
US Ecology provides comprehensive solutions and expertise to government, private sector and engineering firms on a wide variety of site services. We have successfully completed hundreds of environmental projects ranging from low-level radiation decontamination and excavation to on-site remediation, treatment and removal of contaminated soils and landfill closures. We manage remediation projects from start to finish and offer the only integrated environmental services and disposal package in the industry.
