sanborn, head & associates, inc

DES Waste Management Division29 Hazen Drive; PO Box 95 Concord, NH 03302-0095

WORK PLAN FOR FEASIBILITY STUDY Collins & Aikman (former) Plant Site

Farmington, New Hampshire

NHDES Site #: 198705014 Project Number: 211

NHDES Project Type: SuperfundUSEPA ID Number: NHN000105928

Prepared By: Sanborn, Head & Associates, Inc.

20 Foundry Street Concord, NH 03301

Phone Number: (603) 229-1900 Contact Name: Scott R. Nerney, P.E.

Contact Email: [email protected]

Prepared For: New Hampshire Department of

Environmental Services 29 Hazen Drive, PO Box 95

Concord, New Hampshire 03302-0095 Phone Number (603) 271-3649

Contact Name: Michael Summerlin, P.E. Contact Email: [email protected]

Sanborn, Head & Associates, Inc.

Digitally signed by Sanborn, Head & Associates, Inc. Date: 2021.04.22 09:54:50 -04'00'

Date of Report: (April 22, 2021)

Cover Sheet for Reports Template - Revised January 2011

mailto:[email protected]

mailto:[email protected]

SANBORN I 11 HEAD Building Trust. Engineering Success.

SANBORN, HEAD & ASSOCIATES, INC. www.sanbornhead.com

20 Foundry Street Concord, NH 03301

MEMORANDUM

To: Michael Summerlin, NHDES Richard Hull, USEPA

From: Scott R. Nerney Mike K. Abberton Charles A. Crocetti

File: 3856.08

Date: April 22, 2021

Re: Work Plan for Feasibility Study Collins & Aikman Plant (former) Superfund Site Farmington, New Hampshire NHDES Site No. 198705014 NHDES Project No. 211 USEPA ID Number NHN000105928

This document presents the Feasibility Study (FS) Work Plan for the Collins & Aikman (Former) Plant Site located in Farmington, New Hampshire. This FS Work Plan was prepared by Sanborn, Head & Associates, Inc. (Sanborn Head) at the request of the New Hampshire Department of Environmental Services (NHDES) for performance of feasibility study services. This Work Scope and budget estimate were developed under our NHDES Contract for Environmental Consulting Services, approved by Governor and Council on June 5, 2019. A Site Locus Plan is provided as Figure 1.

This Work Plan is based on Sanborn Head’s draft July 8, 2020 Work Plan for Feasibility Study, and comments received from the U.S. Environmental Protection Agency (USEPA) and NHDES on October 26, 2020.

OBJECTIVE AND SCOPE OF SERVICES

The purpose of this Work Plan is to present a proposed scope of work to complete a FS for the Site that includes the preparation of the FS Report. The FS Report will present a range of source control and management of migration remedial alternatives that address risks to human health and the environment identified during the Remedial Investigation (RI). The remedial alternatives developed in the FS will be presented to the U.S. Environmental Protection Agency (USEPA) and NHDES so that an appropriate remedy can be identified which is consistent with the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) Program and the National Oil and Hazardous Substances Contingency Plan (NCP) 40 CFR 300.

This FS Work Plan, in general follows the guidelines to preparing a work plan given in Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA,

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April 2021 Page 2 20210422 FS Work Plan (Rev2).docx 3856.08

Interim Final, USEPA 540/G-89/004, October 1988 (USEPA, 1988). The work plan is based on the progress and findings of the RI to date, as well as discussions with NHDES and USEPA. To meet this objective, we propose the following scope of services.

TASK 100 - REMEDIAL ALTERNATIVES DEVELOPMENT AND SCREENING The objective of this task is to develop an appropriate range of distinct hazardous waste management alternatives that will remediate, control, or limit exposure to contaminated media (i.e., soil, groundwater, sediment, surface water) remaining at the Site so as to provideadequate protection of human health and the environment based on the results of the RiskAssessment. Remedial alternatives will be developed by assembling combinations of technologies, and the media to which they would be applied, into a range of alternatives toaddress Site contamination. The outcome of this task will be a final set of alternatives which will be subject to a detailed analysis under Task 200.

In preparing this FS scope of work, we have assumed that the development and analysis ofremedial alternatives as part of the FS process will be focused primarily on soil and groundwater contaminants at the Site. We have planned for a relatively limited effort in the development and analysis of alternatives to address Site sediment/surface watercontaminants (e.g., monitored natural attenuation [MNA], institutional controls, limited/hotspot sediment excavation) based on our general understanding of Site hydrogeology, the types of Site contaminants, and their distribution in soil and groundwater. However, our understanding of the nature and extent of site-related contamination in sediment and surface water is insufficient at this time to directly assess the potential for significant risk from these media. If the Risk Assessment indicates that these media require a more comprehensive evaluation, we understand that if needed, this evaluation/investigation will be undertaken after the Risk Assessment is finalized. Preparation of the RA is still in its early stages and it is unclear if additional comprehensive evaluations may be required. We will submit a separate work plan and budget estimate for this additional evaluation/investigation, if requested by the Agencies.

Remedial alternatives for the Site will be categorized into Source Control and GroundwaterResponse Actions. In general, the alternatives within each group are anticipated to encompass the following types:

A no-action alternative to be carried forward for baseline comparison purposes in accordance with the NCP;

A limited-action and/or containment alternative that consists of measures to protect human health and the environment by preventing potential exposure and/or reducing the mobility of contaminants, but does not involve treatment/removal; and

For planning purposes, we have assumed approximately three to four treatment/removal alternatives which vary in the degree to which the toxicity, mobility, or volume of contaminants and wastes are reduced will likely be evaluated. If it appears additional alternatives may need to be evaluated, we will discuss with the Agencies the potential need to adjust the scope of this task and any budget implications.

Task 110 - Identification and Compilation of ARARs and TBCs This task will encompass the identification and documentation of applicable or relevant andappropriate requirements (ARARs), as well as standards and guidance to be considered

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(TBCs). By definition, ARARs are promulgated or legally enforceable federal and state, environmental, or public health requirements that are determined to be applicable or relevant and appropriate to the chemicals, remedial actions, or other circumstances at a CERCLA site. Compliance with ARARs is one of the criteria to be evaluated in the detailed analysis of remedial alternatives. If a potential remedial alternative does not comply with identified ARARs, it must be dismissed from consideration unless there is justification for invoking a waiver.

TBCs will also be used in evaluating remedial alternatives. TBCs may include non-promulgated criteria, advisories, guidance, and proposed standards issued by federal or state governments. TBCs are not potential ARARs because they are neither promulgated norenforceable, but they may be considered during development of remedial alternatives. For example, USEPA Health Advisories and Reference Doses are non-promulgated criteria that are used in assessing health risks from contaminants present at CERCLA sites. We anticipate having one meeting/teleconference with NHDES and USEPA as we begin to identify and compile ARARs and TBCs (see Task 400).

ARARs and TBCs are divided into three categories: chemical-specific, location-specific, and action-specific. Chemical-specific ARARs and TBCs are usually health- or risk-based concentrations that may remain in, or be discharged to, the environment. An example oftypical chemical-specific ARARs that will be addressed as part of the FS are federal and statedrinking water standards. Location-specific ARARs are requirements on the implementation of activities associated with a CERCLA site solely because of the specific area in which the site is located. An example of potential location-specific ARARs which may be addressed as part of the FS are federal and state regulations governing activities in wetlands due to the presence of Pokamoonshine Brook on the Site. Action-specific ARARs are usually technology-or activity-based requirements or limitations on actions taken to remediate, handle, treat, transport, or dispose of site wastes, including hazardous wastes. An example of potentialaction-specific ARARs which may be addressed as part of the FS are RCRA regulations as theypertain to design, operation, and monitoring for hazardous waste treatment facilities. A list of potential ARARs and TBCs for the Site, including chemical-, location-, and action-specificrequirements and guidance will be compiled as part of the FS.

Chemical-specific ARARs and TBCs that will be evaluated will include, but may not necessarily be limited to:

Federal Safe Drinking Water Act - MCLs; New Hampshire Primary Drinking Water Criteria; New Hampshire Groundwater Management and Groundwater Release Detection Permits

Rules; New Hampshire Surface Water Quality Standards; and, NHDES Contaminated Sites Management Rules.

Location-specific ARARs and TBCs that will be evaluated will include, but may not necessarily be limited to:

Federal and state wetlands regulations; Federal flood plain regulations and guidance; Federal and state dredging and filling regulations; Federal Fish and Wildlife Coordination Act;

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Federal Endangered Species Act; and Federal historical and archeological resources protection regulations.

Action-specific ARARs and TBCs will be evaluated based on the alternatives developed, andwill likely include, but may not necessarily be limited to:

RCRA regulations pertaining to the treatment, storage, and disposal of hazardous wastes; New Hampshire Hazardous Waste Rules; New Hampshire Groundwater Management and Groundwater Release Detection Permits

Rules; New Hampshire Solid Waste Rules; New Hampshire Rules for Wastewater Treatment Units; and New Hampshire Toxic Air Pollutants regulations.

The above general listing of rules, regulations, standards, and guidance is preliminary andwill be further developed as part of the FS in consultation with NHDES and USEPA.

Compliance with ARARs is one of two “threshold” criteria (the other is overall protection of human health and the environment) that an alternative must achieve in order for it to be selected, unless there are grounds for invoking a waiver. More detailed discussions of the key requirements and the reasons for their applicability or relevance and appropriateness will be integrated into the narrative descriptions of each specific alternative as part of the detailed analysis of remedial alternatives in Task 200. Tables summarizing the identification and documentation of ARARs for each alternative and whether they will be attained by a specific alternative will also be presented in the FS report.

Task 120 - Development of Remedial Action Objectives (RAOs) This task will encompass the development of RAOs for the Site. RAOs consist of media-specific goals to protect human health and the environment. The RAOs specify the media andcontaminants of concern (COCs), exposure routes and receptors, and PreliminaryRemediation Goals (PRGs) for each exposure route. PRGs consist of acceptable contaminantlevels or range of levels which are developed for each contaminant of concern based on chemical specific ARARs and the results of the Human Health and Ecological Risk Assessments, with consideration of background levels. By specifying both exposure pathways and PRGs, the RAOs will permit the development of a range of alternatives that may achieve protection by reducing exposure to contaminated media (e.g., capping an area)or by reducing contaminant concentrations.

The major components of the RAO development process are: identifying the media of concern for the Site, identifying the COCs for each medium, specifying exposure route(s) andreceptor(s), determining PRGs for each exposure route, and formulating RAOs. Even though a preliminary list of RAOs can potentially be developed based on the presence of CVOCcontamination in groundwater, and as anticipated in the FS guidelines for soil contamination,Sanborn Head anticipates the final RAOs will be developed in consultation with NHDES andUSEPA1, and will be based on the results of the RI, including the site-specific Human Healthand Ecological Risk Assessments, as well as ARARs and TBCs, and policy considerations, we

Based on the Agencies’ October 26, 2020 comments, we understand USEPA has already developed a preliminary list of RAOs, which they will provide to Sanborn Head.

1

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anticipate having a meeting/ teleconference with NHDES and USEPA to discuss the range ofRAOs to be developed for the FS (see Task 400).

The media of concern for the Site will be identified based on the results of the site-specific Human Health and Ecological Risk Assessments performed for the RI. The media of concern are expected to be categorized into five major groups: soil, groundwater, sediment, surface water, and nonaqueous phase liquids (NAPLs). As mentioned previously, we have planned to focus our efforts primarily on the soil and groundwater media. We have assumed that because of the current uncertainty regarding the significance of sediment/surface watercontaminants and potential PRGs for these media, the evaluation of these media is likely to be relatively limited unless the results of the Risk Assessment indicate otherwise.

Based on the exposure pathways being considered in the Risk Assessment, and the wide range in variability observed in the soil medium category in terms of physical setting (e.g., surface soils, smear zone soils) and contaminant characteristics (e.g., VOCs, PFAS, metals), the soil category may be divided into the following three sub-categories for ease of presentation and discussion:

Surface Soil: will include contaminated soil at the 0 to 1-foot interval.

Subsurface Soil: anticipated to include contaminated soil at depths of greater than 1 foot, including deeper vadose zone and smear zone (immediately above and/or belowthe water table) soil.

Further subdivision of the soil medium and other categories may be warranted in subsequent stages of the FS (i.e., during the identification and evaluation of remedial technologies) due to variability of contaminant types and concentrations, even within the same category. This variability may preclude the use of a single remedial technology to address all the contaminants in a given medium or medium sub-category. Similarly,subsurface and deeper zone soil contamination characteristics may differ depending on thearea of the Site.

COCs are those chemicals that exceed chemical-specific ARARs for each medium, or in the absence of such standards, contaminants present at concentrations that pose unacceptablehuman health or ecological risks. The COCs for the Site will be identified based on the results of the RI, including the Human Health and Ecological Risk Assessments. The COCs will be presented in a summary table organized according to the various Site media categories, andtheir basis for selection will be discussed in the FS report.

Once the COCs are identified for each medium, potential exposure pathways/receptors willbe specified. For example, potential exposure pathways for COCs in soil will be identified for human and ecological receptors, and may include direct contact, ingestion, and inhalation.The primary exposure pathway for COCs in groundwater is anticipated to be ingestion (i.e.,drinking) by human receptors, and potentially for VOCs, vapor intrusion impacting indoor air quality.

Next, an acceptable contaminant level or range of levels (i.e., PRGs) will be developed for each exposure route. PRGs are media- and chemical-specific contaminant levels that wouldbe protective of human health and the environment if present in Site media. The potential PRGs that will be identified and evaluated in the FS will include:

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Chemical-specific ARARs and TBCs; Concentrations protective of human health (based on the results of the Risk Assessment); Concentrations protective of ecological receptors (based on the results of the Risk

Assessment); Analytical detection limits; and Background concentrations.

In addition, we anticipate that PRGs for contaminant concentrations in soil based on potential leaching to groundwater may be developed based on established leaching standards, accepted leaching models, and/or empirical Site data for soil and groundwater; and PRGs for groundwater.Background concentrations and analytical detection limits for COCs will be included as potential PRGs to ensure selection of cleanup goals that are reasonably attainable and measurable. The PRGs for each COC will be presented in a summary table organizedaccording to the various Site media categories, and their basis for selection will be describedin the FS report.

Based on the COC and PRG development, RAOs will be formulated for each Site medium category. Specific RAO statements will be developed for the protection of human health andthe environment. For example, the RAO for the soil medium category pertaining to the protection of human health may potentially be formulated as follows:

Reduce contamination leaching from soils that would result in groundwater contamination exceeding MCLs, state AGQSs, or acceptable human-health based risk levels.

Also, for the soil medium category, the RAO pertaining to protection of the environment maypotentially be stated as:

Prevent contact by ecological receptors with soils having contaminant concentrations exceeding the ecological risk based PRG.

The above RAO examples are provided to convey a sense of their planned format and presentation in the FS. The actual RAOs for the Site will depend on the findings of the RI, including the Risk Assessments. Further, RAOs will be developed for all the major Site media categories, and they will be summarized in a table that will also include general response actions, remedial technology types, and process options. The format of this table, which includes the RAOs, is discussed as part of Task 150.

The development of RAOs for the Site is contemplated to be an iterative process as the resultsof the RI and Risk Assessments become available. NHDES and USEPA will be consulted during refinement of RAOs as appropriate. Sanborn Head will be available for support inUSEPA’s development of the Proposed Plan for public presentation and comment.

Task 130 - Development of General Response Actions In this task, general response actions will be developed for each medium of interest. Generalresponse actions are measures that may be taken to satisfy the RAOs for the Site and may include institutional actions, containment, excavation, extraction, treatment, disposal, or a combination of these measures. General response actions will be developed for all of the

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major Site media categories, and they will be summarized in a table which will also includeRAOs, remedial technology types, and process options. The format of this table which includes the general response actions is discussed as part of Task 150

At this time, we plan to limit the number of general response actions proposed to address the sediment/surface water media combination to no more than three. The three generalresponse actions that will most likely be evaluated will consist of the following: a no action option; a long-term monitoring option; and a possible option involving limited excavation/dredging of drainage swales, restoration, and monitoring. As mentioned previously, the potential scope of response actions for sediment/surface water will be expanded if deemed necessary based on the findings of the Risk Assessment and in consultation with the Agencies.

Task 140 - Identification of the Volumes or Areas of Contaminated Media In this task, the areas and volumes of media to which the general response actions may be applied will be estimated, taking into consideration potential exposure routes, acceptable exposure levels, and the PRGs, as well as the Site conditions and the nature and extent of contamination. Estimates of the volumes or areas of contaminated media will be an important factor in the subsequent evaluation of the potential applicability of remedial technology types and process options in Task 150. These estimates will also play a key role in the detailed analysis of alternatives under Task 200, particularly in the development of cost estimates for each alternative.

Volume or area estimates will be made for each of the major Site media categories which include soil, groundwater, and NAPL in fractured bedrock, and may include sediment andsurface water pending the results of the ongoing Risk Assessment. These categories may bedivided into various sub-categories. As previously mentioned in the Task 120 discussion, soil may be divided into sub-categories based on depth, and the wide range of variability in contaminant type and concentrations. Groundwater may also be subdivided (e.g., overburden vs. bedrock contamination, plumes from various source areas). Volume/areaestimates for all the relevant Site media will be presented in a summary table and shown onfigures where appropriate.

Task 150 - Identification and Screening of Technologies and Process Options This task will encompass the initial identification and first level of screening of remedial technologies and process options that are potentially applicable to the media, contaminants,and conditions present at the Site. The purpose of this first level screening effort will be to reduce the large array of available technology types and process options by eliminating those which are obviously not applicable to the Site, based on the RAOs and general response actions established by the previous tasks.

The term “technology types” refers to general categories of remedial technologies. The major technology types proposed to be considered for the Site media include:

Institutional controls; Capping; In-situ biological, physical/chemical and thermal treatment; Ex-situ biological, physical/chemical and thermal treatment; and Removal and off-Site treatment/disposal.

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The term “process options” refers to specific processes within each of the above technology categories. For example, the technology type referred to as “in-situ biological treatment” could include such process options as bioventing, enhanced biodegradation, and phytoremediation.

We plan to identify a total of approximately twenty to twenty-five remedial technology process options under the technology type categories listed above. The principal source of information for identifying remedial technology types and process options is anticipated tobe the Federal Remediation Technologies Roundtable’s online Remediation Technologies Screening Matrix (July 2020). The information in this document will be supplemented as necessary by USEPA guidance documents, technical literature, and Sanborn Head experience.

Technology types and process options will be summarized in a table which will also includethe RAOs and general response actions for each medium category. This table is planned to be formatted similar to Table 4-1 of the USEPA guidance document (USEPA, 1988), which includes the following headings:

Environmental Media

Remedial Action Objectives

General Response Actions

Remedial Technology Types

Process Options

After completing the identification step, the candidate remedial technology types and process options will undergo a first level screening, primarily on the basis of technical implementability. The screening step will be accomplished by using the information from the RI regarding contaminant types, concentrations, and on-Site characteristics to eliminate process options and entire technology types that cannot be effectively implemented at the Site.

The initial technology screening step will be documented in a table which will be formattedsimilar to Figure 4-4 of the USEPA guidance document (USEPA, 1988). The screening table is planned to include the following headings:

General Response Action

Remedial Technology

Process Option Description

Screening Comments

We anticipate that approximately five to ten remedial technology process options for each medium will survive the initial screening step.

In the next step, the technologies that make the first cut will undergo a second level of screening with a greater degree of detail. Technologies and process options will be evaluatedbased on three criteria: effectiveness, implementability, and cost. At this stage, the screeningcriteria will be applied only to technologies and the general response actions they are intended to satisfy, and not to the Site as a whole. Consistent with USEPA guidance (USEPA,1988), the evaluation will focus on the criterion of effectiveness, with less effort directed atthe implementability and cost evaluation.

A key objective of this evaluation step is to compare process options within the same technology category. One representative process will be selected, if possible, for each

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technology type to simplify the subsequent development and evaluation of alternatives without limiting flexibility during remedial design. For example, the technology type known as “ex-situ biological treatment” for soil, while consisting of several process options such aslandfarming, biopiles, and bio-slurry reactors, may be adequately represented in subsequentanalysis by the “landfarming” process option alone. More than one process option within thesame technology type may be carried forward, if the processes are sufficiently different intheir performance such that one would not adequately represent the other, or if variable Siteand contaminant characteristics warrant consideration of different process options. For example, within the technology type known as “in-situ physical/chemical treatment” for soil, the process options of “soil vapor extraction” and “solidification/stabilization” may both be retained because of their potential suitability to the different types of contaminants (VOCs and metals, respectively) found at the Site.

Brief descriptions of the second-level screening criteria are provided below:

Effectiveness - This criterion focuses on the potential effectiveness of process options in handling the estimated areas or volumes of media and meeting the remediation goals; the potential impacts to human health and the environment during the construction and implementation phase; and how proven and reliable the process is with respect to the contaminants and conditions at the Site.

Implementability - This criterion encompasses both the technical and administrative feasibility of implementing a process. As indicated above, technical implementability will be used as an initial screen of technology types and process options to eliminate those that are clearly ineffective or impractical at the Site. This subsequent, more detailed evaluation of process options will place greater emphasis on the institutional aspects of implementability, such as: the ability to obtain permits/comply with substantive requirements of permits; the availability of treatment, storage, and disposal services; and availability of equipment, trained personnel, and other resources.

Cost - This criterion plays a limited role in the screening of process options. Relative capital and O&M costs will be used rather than detailed estimates. The cost analysis will be based on engineering judgment, and each process will be evaluated as to whether costs are high, low, or medium relative to other processes in the same technology type.

The detailed evaluation of process options with respect to the three criteria described abovewill be documented in the text of the FS report and in summary tables which will be formatted similar to Figure 4-5 of the USEPA guidance document (USEPA, 1988). The screening table is planned to include the following headings:

General Response

Action Remedial

Technology Process Option Effectiveness Implementability Cost Conclusion

Following the more detailed, second-level screening of technology process options, we anticipate that approximately one to three technologies will be carried forward for each Sitemedium category and the subsequent assembly of Site-wide remedial action alternatives. As mentioned above and in the Task 120 discussion, the Site-specific variability of contaminant

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types and concentrations within the same medium category may warrant the use of multipletechnologies and/or process options for that medium category. The configuration of technology types and process options to address the variability of Site conditions will be conducted as part of the task of remedial alternatives development, which is described next.

Task 160 - Assembly and Screening of Remedial Action Alternatives This task will encompass the configuration and screening of remedial action alternatives. In assembling alternatives, general response actions and the process options chosen to represent the various technology types for each medium will be combined to form alternatives for the Site as a whole. The alternatives will be categorized into Source Controland Groundwater Actions. It is anticipated that a total of up to six alternatives overall will be developed. We anticipate having a meeting/teleconference (see Task 400) with Agencies todiscuss the remedial action alternatives being considered by Sanborn Head for the FS.To assemble a range of alternatives, general response actions will be combined using different technology types and different volumes of media and/or areas of the Site. Due to the variability of the type, distribution, and concentrations of contaminants within a mediumcategory, more than one general response action may be applied to a particular medium.

At this time, we anticipate that the remedial alternatives proposed and developed under theSource Control Actions will incorporate a relatively limited number of general response actions to address sediment/surface water media contamination as previously described under Task 130.

Each alternative will be defined in the FS report to provide sufficient quantitative information to allow differentiation among alternatives with respect to effectiveness, implementability, and cost. Information developed for the various technology processes used in an alternative will include, as appropriate:

Size and configuration of representative process options; Time frame for remediation; Rates of flow or treatment; Spatial requirements for implementing remedial activities; Distances/other limitations for disposal technologies; and Required permits/substantive requirements, imposed limitations, and other legal

considerations.

The FS Statement of Work indicates that if many distinct options are available and developed,a screening of alternatives should be conducted to limit the number of alternatives that undergo the detailed analysis. To streamline the FS process, our intention is to assemble as concise an array of potential alternatives as is practical initially, and hence not requirefurther screening with respect to effectiveness, implementability and cost. Further screeningof the alternatives is not currently planned, and we anticipate that all the alternatives developed will be carried forward for detailed analysis as part of Task 200.

To assist in a smooth transition from the development of alternatives to the detailed analysis,SHA will meet with USEPA and NHDES to discuss which alternatives will undergo detailed analysis, as well as to identify and begin verifying action-specific ARARs.

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TASK 200 - DETAILED ANALYSIS OF ALTERNATIVES This task will encompass a detailed analysis of the remedial action alternatives developed for the Site in the preceding task. The objective of this task is to provide NHDES and USEPA with sufficient information to adequately compare alternatives, select an appropriate remedy for the site, and demonstrate satisfaction of the CERCLA remedy selection requirements in the ROD.As mentioned above, the alternatives will be categorized into Source Control and Groundwater Actions, and we anticipate that a total of up to six alternatives overall will be subject to detailed analysis. The detailed evaluation of alternatives will consist of the following principal components:

Definition of alternatives; Individual analysis of alternatives against nine evaluation criteria; and Comparative analysis of alternatives.

Each of these components is described in more detail below.

Task 210 - Definition of Alternatives This task will consist of developing a technical description of each alternative that outlinesthe waste management strategy involved, including the volumes or areas of contaminated media to be addressed, the technologies to be used, and any performance requirements associated with those technologies. The work of this task will build on the results of Task 160 - Assembly and Screening of Remedial Action Alternatives. Each alternative will be reviewed to determine if additional definition is required to apply the evaluation criteria consistently and to develop cost estimates.

The various alternatives assembled in Task 160 will be refined in this task to potentially include preliminary design calculations, process flow diagrams, sizing of major equipment components, preliminary site layouts, and discussions of the limitations, assumptions, and uncertainties concerning each alternative.

We anticipate that one or more remedial alternatives will include either a pump-and-treat and/or a monitored natural attenuation (MNA) strategy to address groundwater contamination. Sanborn Head understands no numerical groundwater flow model or MNA study will likely be performed prior to completion of the FS, and will not be available to assistin the refinement of the alternatives. Therefore, we anticipate the evaluation of these alternatives will generally be qualitative.

Task 220 - Individual Analysis Against Nine Evaluation Criteria This task will encompass a detailed analysis of alternatives that will consist of an individualanalysis of each alternative against the set of nine evaluation criteria described in the NCP under Section 300.430 (e) 9 (iii). These criteria encompass statutory requirements, and technical, cost and institutional considerations which are considered to be appropriate for a thorough evaluation. We anticipate there will be one meeting/teleconference held with USEPA and NHDES to review Sanborn Head’s evaluation of remedial alternatives relative to the nine criteria (see Task 400)

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The first two criteria listed below which will be evaluated are categorized as threshold criteria in that they relate directly to statutory findings that must ultimately be made in theROD, and therefore they must be met for an alternative to be selected:

Overall Protection of Human Health and the Environment

This evaluation criterion provides a final check to assess whether the alternative provides adequate protection of human health and the environment. Specifically, the evaluation of overall protectiveness will describe how Site risks posed through each exposure pathway are eliminated, reduced or controlled through treatment, engineering actions, or institutional controls.

Compliance with ARARs

This criterion will address whether each alternative will meet all its Federal and State ARARs that have been identified in earlier stages of the FS. The detailed analysis will summarize how the alternative meets ARARs or provide a basis for justifying a waiver when an ARAR will not be met. A summary of the ARARs for each alternative and whether they will be attained will be presented in a table included in the FS report. The table will be formattedsimilar to Appendix E of the USEPA guidance document (USEPA, 1988).

The next five criteria represent the primary “balancing” criteria upon which the comparative analysis of alternatives will be based. They are described briefly below:

Long-term Effectiveness and Permanence

This criterion will evaluate each alternative in terms of the risk remaining at the Site posedby treatment residuals and/or untreated media. This criterion consists of two components:

Magnitude of residual risk - This component will address the residual risk associated with treatment residuals or untreated media remaining at the Site at the conclusion of remedial activities (e.g., after soil containment and or treatment are complete). The potential for risk will be measured, where practicable, by cancer risk levels, or more likely by the concentration or mass/volume of contaminants remaining on the Site (and the resultant exposure to human or ecological receptors) - as a practical matter contaminant mass will be “converted” to risk potential in assessing long term effectiveness.

Adequacy and reliability of controls - This component will address the adequacy, suitability, and long-term reliability of physical and/or institutional controls, if any, that are used to provide continuous protection from residuals or untreated media that remain at the Site.

The evaluation of this criterion will be based on the considerations listed in Table 6-1 of the USEPA guidance document (USEPA, 1988).

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Reduction of Toxicity, Mobility, and/or Volume Through Treatment

This criterion will address the statutory preference for the selection of alternatives which utilize treatment technologies that permanently and significantly reduce toxicity, mobility,and/or volume of the Site contaminants as their primary element. This evaluation will focuson the following specific factors:

The treatment process(es) utilized and the materials they will treat; The amount of hazardous materials that will be destroyed or treated; The degree of anticipated reduction in toxicity, mobility, and/or volume; The degree to which the treatment will be irreversible; The type and quantity of treatment residuals that will remain; and Whether the alternative will satisfy the statutory preference for treatment as a primary

element of the alternative.


Short-term Effectiveness

This criterion will address the effects of the alternative on human health and the environment during construction and implementation of the alternative. The following factors will be addressed as appropriate:

Protection of the community during remedial actions – This factor will address risks resulting from implementation of the alternative, such as dust from excavation, or transportation of contaminated media to off-Site disposal facilities.

Protection of workers during remedial actions – This factor will address risks to workers resulting from implementation of the remedial actions, such as contact with hazardous materials, and the effectiveness and reliability of protective measures that would be required.

Environmental impacts – This factor will address the risks to the environment resulting from implementation of the remedial action, such as erosion and sediment transport, and the effectiveness and reliability of mitigation measures that would be available. Also sustainability/green remediation techniques will be addressed.

Time until achievement of remedial response objectives – This factor will require an estimate of the time required to achieve protection for either the Site as a whole, or individual media categories or Site areas.


Implementability

This criterion will address the following factors associated with the implementability of a remedial alternative:

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Technical feasibility – This factor will assess the feasibility of a remedial technology in terms of construction and operation difficulties and unknowns, reliability, ease of undertaking additional remedial action, if any may be required, and monitoring considerations.

Administrative feasibility – This factor will assess administrative issues, such as ability to achieve permit/substantive requirements for construction and operation.

Availability of services and materials – This factor will assess the availability of services and materials required to implement an alternative, such as off-Site disposal facilities and treatment equipment.

The evaluation of this criterion will be based on the considerations listed in Table 6-4 of the USEPA guidance document (USEPA, 1988).Cost

Preliminary cost estimates will be developed for each alternative. The cost estimates will represent our opinion of the costs associated with implementing each alternative and will not be equivalent to an estimate that a bidder or professional cost estimator may provide once remedial design is completed. Consistent with USEPA’s 1988 guidance for conducting an RI/FS, and USEPA’s Guide to Developing and Documenting Cost Estimates During the Feasibility Study, USEPA 540-R-00-002, July 2000, the cost estimates will attempt to achieve an accuracy of +50 percent to -30 percent. The accuracy of the cost estimates will also in partbe a function of the degree to which there are remaining data gaps following preparation ofthe RI and Risk Assessments. Cost estimates will include the following components:

Capital Costs – This cost component will consist of direct and indirect capital costs. Direct costs may include equipment, materials, labor, transportation and disposal. Indirect costs may include engineering, startup and shakedown, and contingencies.

Annual Operation and Maintenance (O&M) Costs – This cost component will consist of post-construction costs necessary to maintain the on-going effectiveness of the remedial action, and may include labor, materials (e.g., parts, treatment chemicals), energy, compliance sampling, administration, insurance, and periodic Site reviews.

Sources for cost estimates are anticipated to include: Remediation Case Study documents assembled by the Federal Remediation Technologies Roundtable; Environmental Remediation Cost Data: Unit Price and Assemblies Cost Books, 12th Annual Edition, Azimuth Group, Ltd., 2006; vendor quotes obtained as part of the FS efforts; and Sanborn Head experience on similar projects.

Cost estimates for each alternative will be presented in tabular format in an appendix to theFS report, and will include notes concerning assumptions, limitations, and sources of information. A present worth analysis will be conducted to allow the cost of the alternativesto be compared on the basis of a single dollar figure.

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The final two evaluation criteria listed below represent modifying criteria which will be considered in the comparative analysis of alternatives and fully assessed during the public comment period:

State Acceptance

This criterion will address the technical or administrative issues and concerns the State of New Hampshire may have regarding each alternative, including the identification of ARARs, or the proposed use of waivers. We anticipate that NHDES will provide input to the FS process on an on-going basis. Specific State concerns not incorporated into the FS report maybe discussed in the proposed plan to be issued for public comment.

Community Acceptance

This criterion will address the issues and concerns the public may have regarding each alternative. Public concerns will likely be addressed after the public comment period and will be incorporated into a Responsiveness Summary after comments on the RI and FS reports and proposed plan are received.The analysis of individual alternatives with respect to the above nine criteria will be presented in the FS report as a narrative discussion with a summary table. The narrative discussion of the analysis will, for each alternative, present the assessment of the alternative against each of the criteria. This discussion will focus on how, and to what extent, the variousfactors within each of the criteria are addressed.

Task 230 - Comparative Analysis of Alternatives Once the alternatives have been described and individually assessed against the evaluationcriteria, a comparative analysis will be conducted to evaluate the relative performance of each alternative in relation to each specific criterion. The purpose of this comparative analysis is to identify the advantages and disadvantages of each alternative relative to one another so that key tradeoffs can be identified. A narrative discussion of the comparative analysis will be prepared. Results of the comparative analysis will be presented in a tabular form.

TASK 300 - FS REPORT PREPARATION Sanborn Head will present the results of Tasks 100 and 200 in an FS Report. This task will include drafting the report; preparing tables, figures, and associated notes; preparingappendices including supporting data, information, and calculations; and submittal of draftand final reports. A preliminary outline for the FS Report is attached. We have assumed that the report will be issued once in draft form and once in final form. We anticipate that one meeting/teleconference will be held with the Agencies to discuss comments to the draft report (see Task 400).

We anticipate the draft and final reports will be issued in electronic format and reproductionand distribution of paper copies will not be required. We anticipate figures will typically be prepared using AutoCAD, ArcGIS, and/or EVS. Consistent with the format of the RI Report,we anticipate figures will be limited to a maximum size of 11" x 17" to the extent practicable.

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TASK 400 – MEETINGS/TELECONFERENCES ASSOCIATED WITH FS

While we have assumed meetings/teleconferences with USEPA and/or NHDES may cover a variety of topics, for planning purposes we have included time for attendance at five to six potential meetings/teleconferences with USEPA and/or NHDES during performance of the FS. In general, we have assumed these meetings/teleconferences may occur, as follows:

At the start of identifying and compiling ARARs and TBCs;

To discuss the range of RAOs to be developed for the FS;

To discuss the remedial action alternatives being considered;

To review Sanborn Head’s evaluation of remedial alternatives relative to the nine criteria;

To discuss development of the proposed plan and/or to provide public meeting support; and,

To discuss comments to the draft FS Report.

Additional meetings, teleconferences, etc. beyond these are not included in the current scope/budget.

TASK 500 – ONGOING PROJECT MANAGEMENT AND COORDINATION

This task is for our ongoing project management responsibilities for this scope of services which include: time for coordination and communications with NHDES; a portion of our time for our project-scoping discussions with you; preparation of approximately monthly status reports; and general project management activities associated with budget tracking, and scheduling.

BUDGET ESTIMATE AND BASIS OF BILLINGS

The budget estimate for the services described herein is $538,487. A breakdown of the budget estimate by task is provided in Table 1. Billings for Sanborn Head’s services will be based on actual accrued time and expenses in accordance with the Schedule of Fees established in our general services Contract with NHDES in effect at the time of the services being performed. While our billings on a task by task basis may vary from the amounts shown on Table 1, our total billings for this phase of the project will not exceed the amount listed above without your authorization.

SCHEDULE

Based on our current understanding of project requirements, we anticipate that we can initiate FS project-related activities within one to two weeks of your approval of this work plan.

SANBORN 1111 HEAD


ACCEPTANCE AND CLOSING

Sanborn Head understands that you will acknowledge your acceptance of this Work Plan by providing a Work Scope Approval (WSA) to Sanborn Head. Our services will be completed under the Terms and Conditions of the above-referenced contract.

We greatly appreciate the opportunity to be of service to NHDES and USEPA on this project. Please contact us with any questions or issues you may have regarding this document or other aspects of the anticipated work.

SRN/MKA/CAC: srn

Encl. Table 1 - Budget Figure 1 – Locus Plan Preliminary FS Report Outline

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TABLE

TABLE 1 PRELIMINARY BUDGET ESTIMATION WORKSHEET

Work Plan for Feasibility Study Collins & Aikman Plant (Former) Superfund Site

Farmington, NH NHDES Site No. 198705014

TASK

Project Reviewer/ Principal

Technical Manager/

Project Director

Risk Assessor

Sr. Eng/ Sr. PM

QA Manager/

PM

Sr. Proj Engineer

Proj Engineer

Sr. Tech/ Drafter Support

Hours/ task

Sanborn Head Labor

Sanborn Head Exp's Task Totals

$220 $208 $208 $166 $138 $121 $104 $100 $83

100 Remedial Alternatives Development and Screening

110 Identification and Compilation of ARARs and TBCs 2 16 0 40 0 150 60 0 0 268 $34,798 $100 $34,898

120 Development of Remedial Action Objectives (RAOs) 4 16 0 80 0 150 40 0 0 290 $39,798 $100 $39,898

130 Development of General Response Actions 2 12 0 24 0 40 40 0 0 118 $15,920 $100 $16,020

140 Identification of Volumes or Areas of Contaminated Media 2 24 0 40 0 80 40 80 0 266 $33,912 $100 $34,012

150 Identification and Screening of Technologies and Process Options 4 16 0 60 0 120 80 0 0 280 $37,008 $100 $37,108

160 Assembly and Screening of Remedial Action Alternatives 4 16 0 60 0 100 40 80 0 300 $38,428 $100 $38,528

200 Detailed Analysis of Alternatives

210 Definition of Alternatives 4 24 0 100 0 220 40 20 0 408 $55,252 $100 $55,352

220 Individual Analysis Against Nine Evaluation Criteria 4 24 0 160 0 300 60 0 0 548 $74,972 $100 $75,072

230 Comparative Analysis of Alternatives 4 24 0 80 0 180 40 0 0 328 $45,092 $100 $45,192

300 FS Report Preparation 24 96 12 210 0 300 0 150 40 832 $117,224 $600 $117,824

400 Meetings/Teleconferences Associated with FS 10 12 8 40 10 20 0 20 5 125 $19,215 $500 $19,715

500 Ongoing Project Management and Coordination 12 18 0 72 36 0 0 4 8 150 $24,368 $500 $24,868

TOTALS 76 298 20 966 46 1,660 440 354 53 3,913 $535,987 $2,500 $538,487

Notes: 1. See text for additional costing assumptions and limitations. 2. Billings for Sanborn Head's services will be in accordance with the Schedule of Fees established in our general services Contract with NHDES in effect at the time of the services being performed. This table reflects the Schedule of Fees included in Sanborn Head's July 2019 Contract with NHDES.

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FIGURE

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File:P:\3800s\3856.04\Graphics Files\CAD\Locus.dwg Plot Date: 3-11-21 c 2021 SANBORN, HEAD & ASSOCIATES, INC.

Area North of NH Route 11

Area South of NH Route 11

Former Collins & Aikman Property

Notes

1. Base map taken from 7.5 Minute USGS Quadrangle Maps: Farmington, NH & Baxter Lake, NH (1987). 2. Property boundaries are approximate and based on town of Farmington Tax Maps.

Drawn By: E. Wright Designed By: S. Nerney Reviewed By: C. Crocetti

Project No: 3856.08 Date: April 2021

Feet 1000' 0 2000'

SANBORN HEAD

Figure 1

Locus Plan Work Plan for Feasibility Study

Collins and Aikman (Former) Plant Site NH Department of Environmental Services

Farmington, New Hampshire

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PRELIMINARY FS REPORT OUTLINE

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PRELIMINARY FS REPORT OUTLINE

EXECUTIVE SUMMARY

1.0 INTRODUCTION 1.1 Purpose of FS and Organization of FS Report 1.2 Site Background

1.2.1 Site Description 1.2.2 Site History 1.2.3 Previous Investigations/Response Actions

1.3 Site Hydrogeology1.3.1 Site Climate 1.3.2 Site Geology 1.3.3 Surface Water Hydrology 1.3.4 Groundwater Hydrology

1.4 Nature and Extent of Contamination 1.4.1 Distribution of Contaminants in Soils 1.4.2 Distribution of Contaminants in Groundwater 1.4.3 Distribution of Contaminants in Surface Water and Sediment

1.5 Contaminant Transport and Fate 1.6 Baseline Risk Assessment

1.5.1 Human Health Evaluation 1.5.2 Environmental Evaluation

2.0 IDENTIFICATION/DEVELOPMENT OF ARARs AND TBCs, RAOs, GENERAL RESPONSE ACTIONS AND VOLUMES OF CONTAMINATED MEDIA 2.1 Identification and Compilation of ARARs and TBCs

2.1.1 Chemical-Specific ARARs and TBCs 2.1.2 Location Specific ARARs and TBCs 2.1.3 Action-Specific ARARs and TBCs 2.1.4 Policy Considerations

2.2 Development of Remedial Action Objectives2.2.1 Development of Soil RAOs

2.2.1.1 Soil COCs 2.2.1.2 Soil PRGs 2.2.1.3 Soil RAOs

2.2.2 Development of Groundwater RAOs2.2.2.1 Groundwater COCs 2.2.2.2 Groundwater PRGs 2.2.2.3 Groundwater RAOs

2.2.3 Development of Sediment (and Surface Water) RAOs2.2.3.1 Sediment COCs 2.2.3.2 Sediment PRGs 2.2.3.3 Sediment RAOs

2.3 Development of General Response Actions2.3.1 Soil General Response Actions 2.3.2 Groundwater General Response Actions 2.3.3 Sediment General Response Actions

2.4 Identification of Volumes and Areas of Contaminated Media 2.4.1 Areas and Volumes of Contaminated Soil

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April 2021 Page 2 20210422 FS Report Outline (Rev2).docx 3856.08

2.4.2 Areas and Volumes of Contaminated Groundwater 2.4.3 Areas and Volumes of Contaminant Sediment

3.0 IDENTIFICATION AND SCREENING OF TECHNOLOGIES AND PROCESS OPTIONS 3.1 Identification and Screening of Technologies and Process Options

3.1.1 Soil and Sediment 3.1.2 Groundwater

3.2 Evaluation and Selection of Technologies and Process Options3.2.1 Evaluation and Selection of Technologies and Process Options for Soil and

Sediment 3.2.2 Evaluation and Selection of Technologies and Process Options for

Groundwater

4.0 DEVELOPMENT OF REMEDIAL ACTION ALTERNATIVES 4.1 Rationale for Development of Remedial Action Alternatives 4.2 Source Control Alternatives Description 4.3 Management of Migration Alternatives Description 4.4 Screening of Alternatives

5.0 DETAILED ANALYSIS OF ALTERNATIVES 5.1 Individual Analysis of Source Control Alternatives 5.2 Comparative Analysis of Source Control Alternatives 5.3 Individual Analysis of Management of Migration Alternatives 5.4 Comparative Analysis of Management of Migration Alternatives

6.0 REFERENCES

TABLES Table 1 Preliminary List of Applicable or Relevant and Appropriate

Requirements (ARARs) and Criteria To Be Considered (TBCs) Table 2 Contaminants of Concern for Surface Soil Table 3 Preliminary Remediation Goals for Surface Soil Table 4 Contaminants of Concern for Subsurface Soil Table 5 Preliminary Remediation Goals for Subsurface Soil Table 6 Contaminants of Concern for Groundwater Table 7 Preliminary Remediation Goals for Groundwater Table 8 Contaminants of Concern for Sediment Table 9 Preliminary Remediation Goals for Sediment Table 10 Summary of Volumes/Masses and Areas of Contaminated Media Table 11 Remedial Action Objectives, General Response Actions, Technology

Types and Process Options Table 12 Initial Screening of Technologies and Process Options for Surface Soil

and Sediment Table 13 Initial Screening of Technologies and Process Options for Subsurface

Soil Table 14 Initial Screening of Technologies and Process Options for Groundwater Table 15 Evaluation of Process Options for Surface Soil and Sediment Table 16 Evaluation of Process Options for Subsurface Soil Table 17 Evaluation of Process Options for Groundwater

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April 2021 Page 3 20210422 FS Report Outline (Rev2).docx 3856.08

Table 18 – 23

Table 24 Table 25

ARARs and TBCs for Alternatives - (separate tables for up to 6 alternatives) Comparative Analysis of Source Control Alternatives Comparative Analysis of Management of Migration Alternatives

FIGURES Figure 1 Figure 2

Locus Plan Site Vicinity Plan

Figure 3 General Site Features Plan – Entire Site Figure 4 Site Features Detail Plan – Area South of NH Route 11 Figure 5 Exploration Location Plan (Monitoring Wells) – Entire Site Figure 6 Exploration Location Detail Plan (Soil Borings, Monitoring Wells, Test

Pits) – Area South of NH Route 11 Figure 7 Exploration Location Plan (Pore Water) – Entire Site Figure 8 Exploration Location Plan (Surface Water, Sediment, Staff Gauges) –

Entire Site Figure 9 Groundwater Elevation Contour Plans (e.g., Overburden/Bedrock; 2

sets of measurements) Figure 10 – 11 Distribution Summary of Contaminants in Shallow Soil Figure 12 – 13 Distribution Summary of Contaminants in Subsurface Soil Figure 14 – 16 Distribution Summary of Contaminants in Groundwater Figure 17 Distribution Summary of Contaminants in Sediment and Surface Water Figure 18 - 24 Key Components/Schematics/Layouts of Alternatives (separate

figures for up to 6 alternatives)

APPENDICES Appendix A Limitations Appendix B Alternative Development Supporting Information/Calculations Appendix C Cost Estimates and Supporting Information

Others as necessary to support report.

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