North Haven, Connecticut
RCRA Corrective Action
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Aerial View of Site: The Pharmacia-Upjohn site, adjacent to the Quinnipiac River, includes 10 lagoons formerly used to treat wastewater and two associated piles used to manage wastewater treatment residuals.
Results of Carbon Footprint Analysis: The carbon footprint analysis examined four corrective measure alternatives (CMAs) considered in the remedy decision process: CMA #2, maintenance of existing site conditions and long-term O&M; CMA #3, containment of DNAPL and soil/sediment consolidation and cover system construction; CMA #4 (the selected remedy), in situ thermal remediation of DNAPL, soil/sediment excavation and consolidation, and cover system construction; and CMA #5, excavation and offsite disposal of DNAPL and DNAPL-impacted soil/fill, extensive soil/sediment excavation and onsite consolidation, and cover system construction.
Emplaced Slurry: The slurry used to construct the hydraulic barrier wall consisted of a 3:1 mix of furnace slag (a manufacturing byproduct) and Portland cement. The wall extends to an average depth of 17 feet below ground surface.
Low Permeability Hydraulic Barrier Wall: The hydraulic barrier wall runs a total continuous length of 5,367 feet to prevent migration of impacted groundwater into surrounding properties and sensitive ecosystems of the Quinnipiac River as well as the river itself. The hydraulic barrier wall was deemed unnecessary along a western portion of the site perimeter (adjacent to operating railroad tracks) because natural groundwater flow is from west to east.
Low Permeability Cover System Design: The upper protective layer of each completed low permeability cover system includes a 6-inch topsoil layer vegetated with native grass species installed on an 18-inch layer of clean imported soil. Associated porewater, collected during consolidation of the "South Pile" wastewater treatment residuals, is transferred to the groundwater treatment plant.
Cover Construction: The reuse of excavated soil for grading below constructed covers significantly reduced the need to import clean grading fill from offsite sources.
ISTR Pilot System: The ISTR pilot study well field (foreground) and treatment systems for vapor and recovered liquid (background) collectively occupied approximately one-half acre of the 78-acre site.
ISTR Pilot Study Well Field Schematic: The pilot-scale ISTR system used 36 heating wells extending to depths of 36 feet below ground surface to treat DNAPL that accumulated at the top of the existing "Unit 2" low permeability clay. Hydraulic control was provided during the pilot study by the installation of a steel sheet pile wall, keyed approximately five feet into the clay layer, around the perimeter of the well field. The full-scale ISTR system will not require installation of the perimeter steel sheet pile wall because ISTR treatment temperatures above 100°C are not required.
Ecological Enhancements: Ecological restoration along portions of the Quinnipiac River will include creation of a new upland meadow providing habitat for pollinators, songbirds, reptiles and other wildlife.
Freshwater Wetland: The project's conceptual vision of the new freshwater wetland includes habitat likely to attract green frogs, painted turtles, blue herons and other migratory or resident species. The wetland also will serve as a primary tool for managing site-wide stormwater runoff.
Future Reuse Vision: Approximately two-thirds of this 78-acre site will be restored as an ecological preserve. Seventeen acres on the west side, along the active railroad line, will be developed for commercial or light industrial purposes. The adjacent southwest parcel was formerly part of the manufacturing site but is now owned by a separate private party.
Cleanup Objectives: Provide long-term protection of human health and the environment by remediating soil, sediment and groundwater impacted by past releases of manufacturing wastes, wastewater and wastewater treatment residuals, including contaminants such as volatile organic compounds, polychlorinated biphenyls and lead. The remedy for this 78-acre site, located along the Quinnipiac River in south central Connecticut, involves upgrade of the existing groundwater pump-and treat (P&T) system, installation of a perimeter groundwater hydraulic barrier wall, excavation and onsite consolidation of impacted soils, sediment dredging, construction of low permeability and protective soil barrier cover systems, in situ thermal remediation (ISTR) for dense non-aqueous phase liquids (DNAPL) removal, extensive ecological restoration and preparation of a portion of the site for future commercial/light industrial redevelopment opportunities.
Green Remediation Strategy: The strategy focuses on: (1) conducting a quantitative analysis of the carbon footprint of remedial activities and identifying opportunities to reduce the footprint, (2) incorporating green remediation best management practices (BMPs) such as re-using onsite soil, sediment and debris generated during remedy construction, (3) revitalizing the site's ecological systems in a manner that complements the Quinnipiac River ecosystem, and (4) integrating the community's vision for future use. Key studies and findings affecting the strategy include:
- A quantitative assessment of the carbon dioxide (CO2) emissions of the potential corrective measure alternatives, with respect to:
- Transportation of materials required to construct the corrective measure alternatives.
- Major energy use relating to treatment and/or offsite transportation and disposal activities.
- Long-term operation and maintenance (O&M).
- Results of a corrective measure study, including the carbon footprint analysis, which found that:
- A reduction in the rate of groundwater extraction associated with the P&T system could be realized by including low permeability cover systems (to prevent stormwater infiltration) and a perimeter groundwater hydraulic barrier wall (to limit influence of the Quinnipiac River on groundwater levels) without adversely affecting remediation effectiveness.
- Energy usage for treatment of the extracted groundwater could be significantly reduced by achieving a reduction in the rate and volume of groundwater extracted, without adversely affecting the remediation process efficiency.
- Reuse of onsite soil, sediment and debris as grading fill beneath constructed cover systems could significantly reduce the volume of clean soil/fill required to be imported to the site.
- ISTR operations could be optimized through flexible heating temperatures to achieve a balance of energy input (and associated CO2 emissions) versus mass removal rates.
The ASTM Standard Guide for Greener Cleanups (E2893-13) was used to formally document the BMPs and to monitor the environmental footprint reductions achievable or gained by incorporating the BMPs into design and implementation of the corrective action. A total of 129 BMPs potentially applied to the site. In accordance with the standard guide, the applicable BMPs were assigned priorities of high, medium or low and further evaluated to identify influencing factors such as implementation ease or cost. The final BMP implementation plan, as documented in a site-specific greener cleanup technical summary, reflects more than 80 BMPs, including 8 for site assessment, 26 concerning the P&T system, 9 on sediment dredging, 22 relating to the cover systems and 18 regarding the ISTR system.
- Anticipating a minimized carbon footprint over the course of cleanup activities, with mass CO2 emissions estimated at:
- 3,270 tons for installation of cap and cover systems.
- 5,950 tons for ISTR implementation.
- 20,450 tons for long-term O&M.
- Utilized approximately 2,465 tons of recycled ground/granulated blast furnace slag (rather than bentonite, a natural resource) in the construction of the low permeability hydraulic barrier wall, which surrounds approximately 80% of the site. Field tests indicated that a hydraulic barrier wall constructed with Portland cement/slag had a lower permeability than a hydraulic barrier wall constructed with Portland cement/bentonite.
- Used the excavated sediment, drill cuttings and excess grading soil and debris as grading fill below two cover systems for the residual waste, as an alternative to offsite disposal. Similar techniques will be used to construct a third cover system.
- Reduced the rate of groundwater extraction from an average of 180,000 gallons per day to a predicted 62,000 gallons per day by installing the hydraulic barrier wall and the low permeability cover systems rather than relying on groundwater extraction/treatment alone. The groundwater is extracted from a total of seven extraction wells and two groundwater collection trenches, treated at an onsite facility (via biological, chemical coagulation, ultraviolet light oxidation and hydrogen peroxide processes) and discharged into the Quinnipiac River.
- Removed an estimated 26,000 to 41,000 pounds of contaminant mass during pilot-scale ISTR operations in 2012, using a total of 1,122,000 kWh of energy. Performance monitoring indicated that the majority of this mass was removed at 100°C and that use of higher temperatures required large expenditure of energy with diminishing returns of contaminant reduction.
- Used solar-powered air monitoring equipment during the 2012 pilot-scale ISTR; air monitoring during full-scale ISTR also will be solar-powered.
- Used real-time data collection technologies such as a membrane interface probe to guide installation of monitoring wells, and now using down-hole video imagery to assist with well maintenance.
- Constructed a six-acre onsite wetland for long-term management of stormwater, without the need for active pumping or treatment. The constructed wetland also provides critical habitat for freshwater plant and animal species.
- Using native shrubs and grasses typical of the area's upland meadows in the top vegetative layer of each cover system, the back-filled excavation areas and outlying disturbed land.
- Improving habitat linkages in the Quinnipiac River corridor and creating new critical habitat on a regional level through the extensive ecological restoration activities.
- Giving preference to local sources of labor and materials to further reduce the project's offsite transportation-related footprint. Over 30% of the project's labor, services and materials were sourced within 25 miles of the site between November 2011 and June 2014, and over 40% of labor, services and materials were sourced within the State of Connecticut during the same timeframe.
- Minimizing duration of cleanup activities, reducing disruption to the community and expediting beneficial reuse of the property.
- Strengthening support for the proposed remedy and long-term stewardship of the site by engaging local stakeholders in reuse planning, baseline ecological studies and post-remediation ecological restoration planning. Stakeholder groups include the North Haven Citizens' Advisory Panel, North Haven Trail Association, North Haven Land Trust, North Haven Open Space Advisory Committee and Quinnipiac River Watershed Association as well as academic institutions with environmental programs (such as the University of New Haven and Yale School of Forestry and Environmental Science).
Property End Use: Approximately two-thirds of the property will be used as an ecological preserve with restored habitat and an interpretive trail system for environmental education. Seventeen acres will be available for potential commercial or light industrial uses.
Point of Contact: Juan Perez, U.S. Environmental Protection Agency Region 1; Craig Bobrowiecki, Connecticut Department of Energy and Environmental Protection; or Russell Downey and/or Nicholas Andreopoulos, Pfizer Inc.
Update: August 2015