Superfund | CERCLA Landfill Site Environmental Strategy Dover

Environmental Strategy | Landfill Superfund Site

Why GeoInsight

Working on behalf of the Potentially Responsible Party Group (the Group), including the the client, we initially provided third-party review of the Record of Decision (ROD) for the Landfill.  Based on our review, GeoInsight was hired by the Group to amend the remedial approach. We subsequently guided the project team through multiple Pre-Design Investigations (PDIs; see below) that were used to support a Source Control Focused Feasibility Study (SCFFS) to provide a summary of the new information from the PDIs and compare remedial alternatives.  The SCFFS provided the basis to move forward with the Source Control (SC) Remedial Design and implementation. We currently interface with the regulatory agencies and acting as an intermediary in negotiations.


NEGOTIATIONS WITH USEPA AND NHDESReviewed innovative remedial technologies that resulted in an Amended Record of Decision (AROD) and Explanation of Significant Difference (ESD) to document the change in remedial strategy.  This allowed the PRP Group to modify the SC remedy and remove the cap requirement.

SUCCESSFULLY DESIGNED AND CONTSTRUCTED SC REMEDIAL ACTION – Completed 30 Percent to 100 Percent SC Remedial Design to implement groundwater extraction (GWE) at the toe of the Landfill to reduce contaminant migration.  Observed construction and pilot testing of the 45 extraction well GWE system start-up and performed operation and maintenance activities during the initial years of operation.

FOCUSED ASSESSMENT AND REMEDIATION – Implemented PDIs in multiple areas of the site to identify a hot-spot in the Landfill to target focused remedial efforts, including soil vapor extraction and air-sparge.  PDI activities included assessment of ecological impacts and sediment toxicity testing, evaluation of “hot spots” within the landfill, evaluation of the migration and fate and transport of a leachate plume downgradient of the landfill, and evaluation of potential soil vapor intrusion into nearby residences.

Client: Municipal
Location: Southern New Hampshire

Scope of Services

  • Technical Consulting and Field Investigation Activities
  • Project Planning for
    Pre-Design Activities for Impact Delineation and Ecological Impacts
  • Annual Data Collection and Evaluation (from over
    200 monitoring points)
  • Technical Support and
    Scope of Work Negotiations
  • Design and Construction Oversight and Reporting
  • Public Presentations


Project Details

TECHNICAL CONSULTING AND FIELD INVESTIGATION ACTIVITIES – We were part of a technical consultant team that successfully petitioned the USEPA to amend the original ROD for the Site.  Based upon field investigation activities completed by the project team and subsequent negotiations with the regulatory agencies, the USEPA issued an AROD and ESD that changed the original low‑permeability landfill cap remedy to a permeable landfill cap with GWE remedy.

PROJECT PLANS FOR PDI ACTIVITIES – Based upon the AROD, we developed and implemented project plans for completing PDI activities at the Site, including a Site Management Plan (SMP), Health and Safety Plan (HASP), and Quality Assurance Project Plan (QAPP).  The SMP and HASP provided guidelines for site operations, security, personal protective equipment, and site logistics.  The QAPP governed how data would be collected, providing Standard Operating Procedures, data management requirements, and data validation procedures.

DESIGN AND CONSTRUCTION OVERSIGHT AND REPORTING – GeoInsight provided oversight for design and performance of laboratory treatability and limited preliminary field studies confirming initial evaluation of bioremediation, air sparging, and in situ treatment trench remedial evaluations and reviewed deliverables describing the results of these studies.  We reviewed design and construction of the demonstration bioremediation and air sparging treatment systems, performed oversight of its implementation, and assisted in the preparation of deliverables documenting the findings.

ANNUAL DATA COLLECTION AND EVALUATION – On an on-going basis since 2011, GeoInsight manages annual monitoring requirements identified in the Revised Environmental Monitoring Program (REMP)/Groundwater Management Permit (GMP) at the landfill Site.  Data collected includes annual water elevations from over
200 monitoring wells, groundwater quality data collected from approximately 50 monitoring wells, and surface water quality data collected from nearby surface water bodies.  Annual activities include a review of the landfill surface to evaluate for locations of erosion and need for additional soil amendments.

TECHNICAL SUPPORT AND SCOPE OF WORK NEGOTIATIONS – We provided technical support of the Remedial Design/Remedial Action (RD/RA) Consent Decree and scope of work negotiations with the USEPA, United States Department of Justice, and NHDES.  We also reviewed and evaluated a Remedial Investigation and Feasibility Study (RI/FS) to provide technical comments for the PRP Group regarding remedy design, evaluation, selection, and implementation.

QUARTERLY AND ANNUAL REPORTING – GeoInsight prepares quarterly progress reports summarizing Source Control and Management of Migration groundwater extraction operational data and REMP activities.  Source Control GWE system data includes total flow and annual testing of 45 extraction wells.  Annual data is summarized in the Annual Remedy Performance Report that includes data validation, trend analysis, and analysis of the distribution over time.

EMERGING CONTAMINANTS – GeoInsight is monitoring emerging contaminants for possible inclusion into the REMP program.  1,4-dioxane has been incorporated into the annual program and will likely be identified as a Constituent of Concern (COC) using an ESD.  For PFAS evaluation, GeoInsight prepared a Sampling and Analysis Plan; collected background, source area, and plume area groundwater samples to evaluate the extent of potential impact; and is currently negotiating with USEPA regarding continued monitoring approaches and requirements.

PUBLIC PRESENTATIONS – GeoInsight participates in public meetings for the project on an as-needed basis and over the time of our involvement with the project (20 years), has attended and participated in numerous public meetings with the Cities, NHDES, USEPA, and members of the public.  GeoInsight considers public participation a fundamental component of the project and we routinely play a critical role as “translator” and “interpreter” conveying highly technical and complex investigation and regulatory information to the PRP Group, municipalities, and citizens.