Groundwater Remediation

As a leader in the development and application of models in the groundwater industry, SSP&A has applied state-of-the-art evaluation and calculational techniques to design groundwater containment and restoration systems at sites throughout the United States.

The design of a successful groundwater remediation system requires a sound conceptual understanding of hydrologic conditions and correct application of calculational procedures to determine the extent of capture zones for extraction well/drain systems or the hydraulic and geochemical effects of alternative remediation schemes. The use of groundwater flow models expedites and simplifies this process when applied by hydrologists experienced with these techniques, and provides credible results for design and performance evaluation. Along with providing technically sound extraction system designs, SSP&A has successfully applied an understanding of the hydrologic system; contaminant fate and transport mechanisms; risk at receptors; and design goals to streamline monitoring requirements for performance assessment and compliance purposes.

Chem-Dyne Superfund Site

The Chem-Dyne Superfund Site was operated as a hazardous waste treatment plant until closure by the U.S. Environmental Protection Agency and the Ohio Environmental Protection Agency. Spills and dumping of chemicals on the surface of the sand-gravel aquifer had created a plume of contaminated groundwater extending over 40 acres. The remedial plan called for pumping and treating the contaminated water and injecting a portion of the treated water to increase flushing in the aquifer. SSP&A designed and supervised the construction of 25 monitoring wells, 36 piezometers, 18 shallow extraction wells, 7 intermediate extraction wells and 8 injection wells. The system began operating in February 1987, and through 1992 an average of nearly one million gallons per day were pumped and treated, with over one-third of the treated water re-injected. The balance of the treatment water was discharged to the Ford Hydraulic Canal, which flows into the Great Miami River.

In October 1992, a chemical assessment conducted by SSP&A showed that the plume had been sufficiently diluted to the point that water from the treatment plant could be discharged directly to surface water, without the need for injection. The injection wells were shut down at this time. The contaminant load from the treated water currently meets the applicable NPDES limits and is discharged into the Ford Hydraulic Canal.

SSP&A continued to monitor withdrawal rates, well performance, water-level responses and quality changes and prepared an annual report on water-level and water-quality changes through 2008. SSP&A also recommended and supervised redevelopment of extraction wells affected by the growth of iron bacteria and advises on the amount and distribution of withdrawals from the extraction wells.

Hytek Extraction Well System - Kent, Washington

SSP&A was retained to review a planned extraction well system at a manufacturing facility in Kent, Washington, regulated under a RCRA Post Closure Permit. Groundwater contamination consisted primarily of TCE, 1,2- DCE, and vinyl chloride, ranging from very high concentrations, indicative of DNAPL, near the disposal area, to relatively low concentrations at the site boundary. The planned extraction system consisted of two well groups, one group near the source area, and another group along the site boundary.

Following an evaluation of hydrogeologic conditions at the site, including 2-D and 3-D modeling analyses, SSP&A determined that the planned system was inadequate to capture the plume, and that pumping rates six times greater than those originally planned would be necessary. SSP&A designed an alternate recovery well system and prepared a work plan for the installation and testing of the expanded recovery well system. SSP&A supervised the installation of five extraction wells and six monitor wells at the site, and performed and analyzed five aquifer tests. Following a two-week pilot pumping period, SSP&A fine-tuned site hydrologic models using the pilot operational data and determined the required operational pumping rates for the extraction well system. SSP&A participated in negotiations with the EPA and State of Washington Department of Ecology to gain final approval of the system and approval of a performance evaluation plan for demonstrating capture during system operation. Since extraction system start-up in 1992, SSP&A has conducted annual evaluations of the adequacy of capture and remedial progress.

ReSolve Superfund Site

SSP&A prepared the Preliminary Design for an extraction well system at the ReSolve Superfund Site to contain and restore, where practical, groundwater contaminated with PCE and other volatile organic compounds. Work included an assessment of geochemical and hydrogeologic data to identify the potential extent of DNAPL and dissolved phase contaminants; analyses of aquifer tests; development and calibration of a 3-D numerical groundwater flow and particle tracking model; modeling analyses of alternate extraction well scenarios; and design of an extraction well system considering performance objectives, wetland issues and risk of DNAPL re-mobilization. SSP&A served on an Expert Committee assembled to provide state-of-the-art advice on DNAPL issues.

Heleva Landfill Superfund Site - Whitehall Township, Pennsylvania

SSP&A performed site characterization and remedial design at this Superfund site to address VOCs in groundwater extending from the landfill to downgradient residential areas. Primary goals at the site have been conducting hydrogeologic and hydrochemical investigations to characterize groundwater flow and water quality conditions; evaluating the extent of DNAPL contamination; and developing a conceptual design for groundwater containment and restoration. Specific activities have included monitoring, hydraulic testing, geochemical investigations, groundwater flow modeling, capture zone analysis, fate and transport modeling, and DNAPL assessments as part of the Remedial Design for the site under an Administrative Order. SSP&A has provided technical analysis in support of insurance litigation and in support of negotiations related to the issuance of a ROD Amendment and the Administrative Order.

Intersil Facility - Sunnyvale, California

SSP&A conducted numerical flow modeling and contaminant transport modeling at the former Intersil facility in Sunnyvale, California. The facility is underlain by a shallow plume of multiple contaminants, including PCE, TCE, and 1,2-DCE. The plume, which has multiple sources, is believed to have originated in part through spreading from a pool of DNAPLs located beneath a leaking underground pipeline. SSP&A used the results of the groundwater and transport modeling to evaluate the effectiveness of several alternative configurations for the pump-and-treat extraction system for groundwater remediation. The design of the system was optimized under a number of constraints, including total clean-up time and cost. SSP&A also evaluated the currently-operating extraction system and devised a cost-allocation scheme between Intersil and adjacent facilities.

Kodak Park West

SSP&A developed and calibrated a three-dimensional groundwater flow model for Kodak Park West, a section of the Kodak Park industrial complex, and used it to estimate directions and rates of groundwater flow and to evaluate remedial options. The site is an extensive industrial facility used for film manufacturing and processing and is currently under regulation as a RCRA facility. The model utilizes a finite-difference mesh of five layers and represents flow in a sequence of hydrogeologic units underlying the site. Using the model, SSP&A developed a detailed groundwater budget for Kodak Park West, determined the existing pattern of groundwater flow in each hydrogeologic unit, and tested proposed remedial measures. The model-development process and the results of hydrogeologic calculations made with the model were summarized in a detailed project report.

Martin-Marietta Facility - Denver, Colorado

SSP&A developed a linked groundwater and surface water flow model for the shallow alluvial aquifer, the Pierre Shale and other dipping bedrock units to evaluate the fate and transport of VOCs, metals, and other contaminants from onsite manufacturing areas to the downgradient river alluvium and the South Platte River. SSP&A used the model to evaluate the risk to Denver municipal wells located in the river alluvium and to evaluate the effectiveness of existing interim groundwater interception measures. SSP&A also performed modeling and fate and transport evaluations to evaluate alternate groundwater remedial measures and determine optimal well locations in alluvial channels for expediting the clean-up. SSP&A provided these technical services to complement engineering services provided by another consultant retained by the facility in the conduct of the RI/FS.

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Micro Motion, Inc.

SSP&A was retained to determine whether the source of a VOC plume in groundwater beneath this manufacturing facility was at the client’s facility or a neighboring facility that conducts similar manufacturing activities. Investigations included design and implementation of drilling, sampling, and hydraulic testing. Based on geochemical and hydrogeologic data from the field investigations, SSP&A was able to identify the source of the VOC plume as originating from the adjacent property.

To evaluate proposed extraction well and trench scenarios, SSP&A designed a groundwater flow model and conducted capture zone analyses. In addition, SSP&A provided technical support in the environmental liability and cost-recovery action and made recommendations for the Corrective Action Plan that was implemented by the up-gradient neighbor under a Consent Order. SSP&A also provided oversight of soil and groundwater remedial actions.

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