This Pollution Report (POLREP) documents progress in cleanup activities at the Wampus Milford Associates Site, located at 80 Wampus Lane in Milford, Connecticut. The 24-acre parcel was formerly owned and operated by the Burndy Corporation, beginning in 1956, for the manufacture of electrical components and accessories. Operations included manufacture of rubber and plastic molding, operation of power presses, screw machining, degreasing, plating, wastewater treatment, soldering, assembly, and shipping. All outstanding stock of the Burndy Corporation was purchased by Framatome Connectors International in 1989. In 1993, all operations at the facility ceased. In 1995, the company name was changed from the Burndy Corporation to Framatome Connectors USA. In 1999, ownership of the Site was subsequently transferred to Wampus Milford Associates, LLC.
While the facility was operational, metal hydroxide sludges from the treatment of electroplating wastes were accumulated in two on-site surface impoundments and disposed of in an on-site landfill. These areas of concern were previously remediated by the property owner under the direct oversight of the Connecticut Department of Environmental Protection (CTDEP).
The current cleanup, being performed under EPA oversight by HRP Associates, on behalf of FCI USA, Inc., is addressing contaminated surface soils within and adjacent to a man-made, earthen drainage swale on the property.
Previous investigations by EPA revealed that contaminants, including beryllium, lead, polycyclic aromatic hydrocarbons (PAHs) and petroleum hydrocarbons (TPH) are present in soils within the drainage swale. The swale is approximately 210 feet long and of varying width, with a ponding area and weir, and reportedly received treated plating wastewater and stormwater run-off between
1965 and 1991.
Soil excavation was completed on Thursday, October 18, 2007, with the removal of approximately 1,000 tons of contaminated soils. Soils were staged on the property within a lined, bermed containment area within the fenced zone and segregated into piles that exhibited similar levels of lead and cadmium.
Waste disposal characterization samples that were submitted for laboratory analysis of metals, total cyanide, total petroleum hydrocarbons (TPH), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), conductivity, pH, flashpoint, and reactive cyanide and sulfide showed elevated levels of certain constituents, including, but not limited to, metals (including lead and cadmium) and PAHs. Samples from one waste pile exhibited levels of cadmium (via the Toxicity Characteristic Leaching Procedure or TCLP) at 2.24 mg/l, which exceeds the regulatory limit for characteristically hazardous waste. Based on these sampling results, these soils (approximately 260 tons) were classified as characteristically hazardous waste and, on December 5, 2007, transported to an EPA-approved treatment facility (Clean Earth in South Kearny, New Jersey; EPA ID# NJD991291105) for stabilization and disposal. The remaining soil was classified as non-hazardous waste and shipped to the Clean Earth facility on December 11, 2007.
A survey of the swale was performed in order to establish grade stakes to guide the restoration of the swale and on November 14, 2007 crews re-mobilized to the site to begin the work. During the first two weeks of December backfilling and grading of the swale to pre-existing grades was completed. Gravel from the former haul road, which had previously been sampled for extractable total petroleum hydrocarbons (ETPH), metals, and PAHs and been confirmed acceptable, was placed along the bottom and sides of the swale throughout its length, both within the portion upstream of the weir (the former storm water collection area) and downstream of the weir to Stubby Plain Brook. Clean fill materials were subsequently placed on top of the gravel layer. The plastic sheeting and overflow pipe were removed from the storm water collection area; the remaining stumps and logs were also removed. Topsoil was placed within the area adjacent to the brook and along the margins of the swale channel, and on December 4, 2007, a New England Seed Wet Mix was placed over the disturbed areas and erosion control mats deployed over the seeded areas. Following the backfilling, the swale grade was surveyed to confirm the finish elevation.
During the period of excavation in the wetland area adjacent to Stubby Plain Brook, groundwater was pumped via the previously installed dewatering wells to the three 20,000-gallon frac tanks, and subsequently treated and discharged back to Stubby Plain Brook. The discharge area was located to the east of the swale in the woods, with the treated effluent discharged to the brook via a constructed Rip Rap pad that dissipated flow velocity and prevented erosion of the land surface. The extracted groundwater was treated by settling of solids, bag filtration, and carbon adsorption prior to discharge to the brook. Samples were collected of the untreated and treated effluent and submitted for laboratory analysis of metals, volatile organic chemicals (VOCs), PAHs, cyanide, pH, settlable solids, and TPH.
Test results of the untreated groundwater showed metals, including cadmium, copper, and lead, and trace levels of VOCs to be present, consistent with previously characterized groundwater conditions at the Site. Test results of the treated effluent showed all contaminants to be reduced to well below site action levels, with the exception of lead, which was detected at levels of 13.4 and 11.5 ug/L, slightly above the site action level of 9.8 ug/L. Subsequent sampling for total and dissolved lead occurred while treated effluent was re-circulated into the settling tank, without discharging water to the brook. Test results showed a lead removal efficiency of about 74%, but indicated that residual suspended sediment was likely passing through the filter and carbon unit.
In order to improve treatment efficiency, the 20-micron bag filter was replaced with a 5-micron filter to improve the removal of suspended particles in the water passing through the carbon unit. A second set of samples was then collected to assess the treatment performance for lead resulting from this change. One set of results indicated total lead to be present above discharge limits (based on a 10:1 dilution in the brook) in the treated sample, despite the use of the finer bag filter. Given the results, discharge to the brook on November 21, 2007 subsequently proceeded at a reduced pumping rate (4 gallons per minute or gpm) in order to comply with a 100:1 dilution discharge limit for lead (93.6 ug/L). Approximately 1,000 gallons of water were treated and discharged over approximately a 4-hour period. An effluent sample was collected (AOC1-DSN001-005) and submitted for analysis of metals, VOCs, PAHs, cyanide, pH, settlable solids, and TPH. Test results of the treated effluent showed all contaminants to be reduced to well below site action levels. In particular, the level of lead was not detected above the laboratory reporting limit of 7.5 ug/L.
During the week of November 26, 2007 the remaining water in the settling tank was treated and discharged to the Stubby Plain Brook, at the reduced flow rate of approximately 4 gpm. An effluent sample was collected (AOC1-DSN001-006) and submitted for analysis of metals, VOCs, PAHs, cyanide, pH, settlable solids, and TPH. Test results of the treated effluent showed all contaminants to be reduced to well below site action levels. In this sample, the level of lead was reported to be 8.6 ug/L.
Following the completion of the dewatering, the wells were removed from the ground by utilizing the excavator. The dewatering piping and pump connecting the wells and settling tank were dismantled, decontaminated, and removed from the site on November 21, 2007.
All construction-related equipment, including the “frac” tanks and carbon and filter units associated with the groundwater treatment system, were decontaminated and removed off-site, with the exception of the office trailer, which will be removed off-site shortly. The remaining portions of the haul road which previously connected the excavation area with the soil staging area were also removed. The remaining chain-link fencing surrounding the work zones was dismantled on December 13, 2007.
Perimeter air monitoring for particulates (dusts) and VOCs continued throughout the work period, showing no sustained readings above site action levels that were attributed to the removal activities occurring on the property. Throughout the work period dust levels remained well below the levels detected at the background station. Results from the personal air monitoring and sampling for metals and dusts showed no exceedences of site action levels. All concentrations of detected analytes were at trace levels, remaining several orders of magnitude below site action levels.
No further removal actions are planned.
The erosion controls, including the silt fence, will remain in place throughout the winter and into the 2008 growing season. The restored swale and excavation area will be monitored regularly by EPA and HRP Associates throughout the winter, with additional inspections following significant storm events.
Wetland vegetation, including trees, shrubs, and herbs will be planted early in the 2008 growing season (April or May). Following the completion of the plantings, quarterly on-site inspections for up to one year will be conducted to evaluate the condition of restored swale area and the newly installed vegetative cover.
During the period of waste shipment, HRP Associates coordinated closely with the Milford Police Department to arrange for traffic control along Gulf Street and the intersection with Cherry Street. The traffic control plan included a route away from the center of town and time restrictions for arrival and departure to and from the site, so as to minimize interference with school-related traffic and the rush hour commute.
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