Completed Work

The SRSNE Site Group has retained a variety of consultants and contractors to design and implement the remedy for the Site.  These firms are listed in the “Site Contacts” section of this web site.   Together, these firms have prepared a Remedial Design Work Plan (RDWP) that was approved by EPA and CTDEEP in 2010. The RDWP is a comprehensive document that:  summarizes pertinent Site-related background information, identifies and describes the scopes and procedures for various pre-design investigations, describes the anticipated RD process, and discusses the RD-related deliverables and schedule.  Section V.C.1 of the SOW requires that the RDWP includes descriptions of a series of pre-design and design-related activities that are to be undertaken to support the final remedial action. These plans, plus additional plans proactively developed to facilitate design and implementation of specific components of the final remedy, are presented as attachments to the RDWP.  These supporting documents include the following (a brief description of each is also provided):

Attachment A – Overburden NAPL Delineation Plan  (Describes planned investigation to delineate the extent of NAPL in the overburden in the northwest corner of the former Operations Area and includes provisions for collection of samples to support ISTR pre-design testing.)

Attachment B – Thermal Treatment Monitoring Plan  (Describes the scope and approach for monitoring air quality within and around the perimeter of the ISTR area during construction, implementation, and demobilization activities to minimize potential impacts to onsite workers and the community. This plan also includes an action level exceedance plan that provides the USEPA, CTDEEP, and the community with the information they need to recognize and respond to a release.)

Attachment C – Thermal Treatment Performance Criteria Work Plan (Describes the scope and approach for performance monitoring of the In-Situ Thermal Desorption (ISTD) system to determine the progress, demonstrate compliance with the applicable permit equivalency requirements, and monitor the quality of any air or water discharges from the system.)

Attachment D – Vapor Treatment Needs Evaluation Work Plan (Evaluates commercially available and proven vapor treatment technologies suitable for treating both the range and anticipated mass load of the SRSNE Site COCs. Focus is on the use of thermal oxidation with and without condensing.)

Attachment E – System Design Evaluation Work Plan  (Describes the scope and approach for undertaking two design evaluations to support the In-Situ Thermal Desorption (ISTD) system design: 1) a materials compatibility study to evaluate the potential for corrosion of subsurface and above ground system components, and 2) numerical calculations upon which to base the sizing of the heating and treatment equipment.)

Attachment F – NAPL Mobilization Assessment and Mitigation Plan (Describes the potential for DNAPL mobilization during ISTD implementation and the safety measures that will be implemented to prevent mobilization and to mitigate it if it occurs. This plan also references other plans and design documents that describe system features designed to minimize vapor releases.)

Attachment G  – Post-Excavation Confirmatory Sampling Plan (Describes approach for bottom and/or sidewall sampling to confirm achievement of cleanup levels in areas where soil excavation is performed to address soils exceeding established cleanup goals.)

Attachment H – Habitat Restoration Work Plan (Describes plan for assessing, mitigating impacts to, restoring, and monitoring restored habitat areas during RD/RA activities.)

Attachment I – Soil Investigation Plan (Describes plan for soil sampling to establish background dioxin concentrations in soil, confirm the extent of the cap areas, and further assess/ delineate the targeted soil removal areas on the former Cianci Property.)

Attachment J – Vapor Control System Evaluation (Describes the approach for assessing the potential need for vapor controls as a component of the RCRA C cap to be constructed in the former SRSNE Operations Area.)

Attachment K – Vapor Intrusion Study Work Plan (Describes the approach to evaluating the potential for vapor intrusion (VI) from groundwater. Outlines steps to be taken based on results of screening level comparisons.)

Attachment L – Monitored Natural Attenuation Plan (Describes the Site Conceptual Model developed in support of selection of MNA as a remedy for constituents in Site groundwater, and presents the Performance Monitoring Plan for the MNA portion of the overall Site remedy.)

Attachment M – Pre-ISTR Preparation Plan (Describes initial Site preparation activities to be performed prior to implementing the in-situ thermal treatment component of the remedy.)

Attachment N – Monitoring Well Network Evaluation and Groundwater Monitoring Program (Describes planned modifications to the groundwater monitoring network, presents various aspects of the monitoring program, and summarizes the scope and timing for the monitoring events. The evaluation considered the anticipated need for groundwater monitoring to address various SOW requirements, including MNA evaluations, compliance monitoring, VI evaluations, and monitoring during ISTR implementation.)

Attachment O – Groundwater Containment and Treatment Evaluation and Optimization Study Work Plan (Describes the proposed approach for evaluating and optimizing the performance of the groundwater extraction and treatment system after groundwater conditions return to equilibrium after in-situ thermal treatment)

Another part of the RDWP is the RD Project Operations Plan, or “RD POP” (which includes Attachments A – E).   The RD POP provides details for all how all the necessary field investigations shall be conducted, and consists of and introductory document, schedule, and the following attachments:

Attachment A – Site Management Plan (The SMP describes how the RD activities will be managed. The overall objective of the SMP is to provide USEPA and CTDEEP with a written understanding of how various project aspects such as access, security, contingency procedures, management responsibilities, waste disposal, budgeting, and data handling will be performed by the SRSNE Site Group.)

Sampling and Analysis Plan

Attachment B – Field Sampling Plan  (The FSP establishes sample collection and field monitoring methods and procedures to ensure that sampling and investigatory activities are conducted in a consistent manner and in accordance with technically acceptable protocols. The objective of the FSP is to facilitate the collection of environmental monitoring data that meets Data Quality Objectives (DQOs) established in the QAPP.)

Attachment C – Quality Assurance Project Plan  (The QAPP supplements the RDWP and presents the sampling and analytical methods and procedures that will be used during RD investigations at the Site. It integrates the technical and quality aspects of the project into an approach for obtaining the type and quality of environmental data and information needed for a specific decision or use. )

Attachment D – Health and Safety Plan (The HASP establishes the minimum procedures, personnel responsibilities and training necessary to protect the health and safety of all on-site personnel during the RD activities, including routine but potentially hazardous field activities and unexpected site emergencies.)

Attachment E – Community Relations Support Plan (The CRSP summarizes pertinent information regarding the Site history and anticipated public involvement activities, and describes how the SRSNE Site Group will support USEPA’s implementation of a Community Relations Support Plan.)

Various studies proposed in the Remedial Design Work Plan to guide the development of the design have been completed, including the delineation of the extent of overburden NAPL, evaluation of the potential for vapor intrusion to nearby structures, and the delineation of the extent of NAPL and VOC plumes in bedrock. As the designs for remediation of affected media are completed and approved by EPA and CTDEEP, these documents will also be posted to this website.

A conceptual design for in-situ thermal remediation (ISTR) was submitted for EPA and CTDEEP review in April 2010.   Based on this document, all of the necessary site infrastructure changes (grading, drainage systems, re-routing of a major fiber optic service, installation of natural gas and electric lines, and installation of sheet piling to control groundwater flow) were consolidated in one design, the “Pre-In-Situ Thermal Remediation Preparation Plan” or “PIPP”.   The PIPP was approved, and the work implemented between Fall 2010 and Fall 2012.  EPA approved the design of the ISTR wellfield in September 2011, and installation began in April 2013.  The ISTR system is expected to start operation in late 2013, and continue into the summer of 2014.   After completion of ISTR, the system will be demobilized, and a cap placed over the treated area.

Consistent with the ROD, operation of the groundwater containment and treatment system installed in 1995 and 1998 pursuant to the NTCRA orders has continued.  This system will be optimized after ISTR is completed.

A program to routinely monitor groundwater contamination was included in the RDWP.  That work has included completion of the delineation of the extent of contamination in bedrock, and regular monitoring of the groundwater.   The results of the groundwater treatment and monitoring are included in the Annual Compliance Reports.

The most recent groundwater monitoring results are shown in the following figures.  Five groundwater zones are currently monitored at the SRSNE Site:

  • Shallow, middle, and deep overburden, which represents the upper, middle, and lower thirds of the saturated overburden deposits, respectively
  • Shallow and deep bedrock, which represent approximately the upper 30 feet of bedrock, and the portion more than 30 feet below the top of rock, respectively.