Posts

Brownfields Road Map (U.S. EPA, 2018)

Prepared by the U.S. Environmental Protection Agency (U.S. EPA) Office of Land and Emergency Management, The Brownfields Road Map 6th Edition breaks down Brownfields site investigation and cleanup into an easy to understand, step-by-step process that provides valuable and up-to-date information to a wide range of Brownfields stakeholders involved in or affected by the redevelopment of Brownfields sites. It introduces readers to a range of considerations and activities, and provides links to online technical resources and tools.

The first edition of the Road Map, published in 1997, provided a broad overview of the U.S. EPA Brownfields Program and an outline of the steps involved in the cleanup of a Brownfields site. Designed primarily for stakeholders who were unfamiliar with the elements of cleaning up a Brownfields site, the Road Map built awareness of the advantages offered by innovative technologies. As the EPA Brownfields Program
matured, the second (1999), third (2001), and fourth (2005) editions were published to update information and resources associated with the program, innovative technologies, and emerging best practices. The fifth edition, published in 2012, streamlined the publication to make it more accessible to users, providing additional resources covering new technology applications and methods.

This edition builds off the streamlined approach of the fifth edition, providing updated content and guidance on the Brownfields remediation process. New features include an updated list of “Spotlights,” highlighting and describing key issues. This edition provides updated information on Brownfields funding and best management practices (BMPs), with guidance on how to incorporate greener cleanups and new standards into the cleanup process.

This edition of the Road Map will help:

  • New and less experienced stakeholders. The Road Map will help these users learn about the technical aspects of Brownfields by introducing general concepts and methods for site investigation and cleanup.
  • Decision-makers who are familiar with the EPA Brownfields Program but are also interested in obtaining more detailed information. The Road Map provides these users with up-to-date information about the applicability of technologies and access to the latest resources that can assist them in making technology decisions. In addition, it highlights BMPs that have emerged in recent years.
  • Community members. The Road Map helps to encourage community members to participate in the decision making process by providing information about the general site cleanup process and tools and alternatives to site cleanup, as well as guidelines and mechanisms to promote community involvement.
  • Tribal leaders. The Road Map offers information on technical and financial assistance specific to tribes for implementing cleanup and restoration activities on tribal lands, as well as successful remediation examples highlighting the potential community restoration opportunities associated with Section 128(a) Response Program funding.
  • Stakeholders who hire or oversee site cleanup professionals. The Road Map includes information to help stakeholders coordinate with many different cleanup practitioners, such as environmental professionals, cleanup service providers, technology vendors or staff of analytical laboratories. The Road Map provides these stakeholders with a detailed understanding of each phase in a typical Brownfields site cleanup and presents information about the roles that environmental practitioners play in the process.
  • Regulators. The Road Map will increase the understanding by regulatory personnel of site characterization and cleanup technologies and approaches. The Road Map also serves as a resource that regulators can use to provide site owners, service providers and other stakeholders with useful information about the EPA Brownfields Program. The Road Map also provides links and pointers to additional information on specific technologies, approaches, and issues.
  • Other potential Brownfields stakeholders. The Road Map helps other stakeholders, such as financial institutions and insurance agencies, by providing information for their use in assessing and minimizing financial risks associated with Brownfields redevelopment.

The Road Map draws on the EPA’s experiences with Brownfields sites, as well as Superfund sites, corrective action sites under the Resource Conservation and Recovery Act (RCRA), and underground storage tank (UST) sites to provide technical information useful to Brownfield stakeholders. Specific conditions—such as the nature and extent of contamination, the proposed reuses of the property, the financial resources available, and the level of support from neighboring communities—vary from site to site. Readers of the Road Map are encouraged to explore opportunities to use the BMPs described in the following pages in accordance with applicable regulatory program requirements. The use of BMPs and site characterization and cleanup technologies may require site specific decisions to be made with input from state, tribal, and/or local regulators and other oversight bodies.

 

Guideline for the Management of Sites Contaminated with Light Non-Aqueous Phase Liquids

Light Non-Aqueous Phase Liquid (LNAPL) Management is the process of LNAPL site assessment, monitoring, LNAPL Conceptual Site Model development, identification and validation of relevant LNAPL concerns, and the possible application of remediation technologies. The presence of LNAPL can create challenges at any site.  Examples of LNAPLs include gasoline, diesel fuel, and petroleum oil.

In 2009, the United States Interstate Technology and Regulatory Council (ITRC) published LNAPL-1: Evaluating Natural Source Zone Depletion at Sites with LNAPL (ITRC 2009b) and LNAPL-2: Evaluating LNAPL Remedial Technologies for Achieving Project Goals (ITRC 2009a) to aid in the understanding, cleanup, and management of LNAPL at thousands of sites with varied uses and complexities. These documents have been effective in assisting implementing agencies, responsible parties, and other practitioners to identify concerns, discriminate between LNAPL composition and saturation-based goals, to screen remedial technologies efficiently, to better define metrics and endpoints for removal of LNAPL to the “maximum extent practicable,” and to move sites toward an acceptable resolution and eventual case closure.

This guidance, LNAPL-3: LNAPL Site Management: LCSM Evolution, Decision Process, and Remedial Technologies, builds upon and supersedes both previous ITRC LNAPL guidance documents in an updated, web-based format. LNAPL-1 and LNAPL-2 are still available for review; however, LNAPL-3 is inclusive of those materials with new topics presented and previous topics elaborated upon and further clarified.

This guidance can be used for any LNAPL site regardless of size and site use and provides a systematic framework to:

  • develop a comprehensive LNAPL Conceptual Site Model (LCSM) for the purpose of identifying specific LNAPL concerns;
  • establish appropriate LNAPL remedial goals and specific, measurable, attainable, relevant, and timely (SMART) objectives for identified LNAPL concerns that may warrant remedial consideration;
  • inform stakeholders of the applicability and capability of various LNAPL remedial technologies
  • select remedial technologies that will best achieve the LNAPL remedial goals for a site, in the context of the identified LNAPL concerns and conditions;
  • describe the process for transitioning between LNAPL strategies or technologies as the site moves through investigation, cleanup, and beyond; and
  • evaluate the implemented remedial technologies to measure progress toward an identified technology specific endpoint.

Initial development and continued refinement of the LCSM is important to the identification and ultimate abatement of site-specific LNAPL concerns. Figure 1-1 identifies the stepwise evolution of the LCSM, the specific purpose of each LCSM phase, and the tools presented within this guidance to aid in the development of the LCSM. As depicted, the LCSM is the driving force for identifying actions to bring an LNAPL site to regulatory closure.

LNAPL remediation process and evolution of the LNAPL conceptual site model (LCSM).

This guidance document is organized into sections that lead you through the LNAPL site management process:

  • Section 2 – LNAPL Regulatory Context, Challenges, and Outreach
    Section 2 identifies some of the challenges implementing agencies face when investigating, evaluating, or remediating LNAPL sites. These challenges include regulatory or guidance constraints, a lack of familiarity or understanding of LNAPL issues, and poorly or undefined objectives and strategies. This section also stresses the importance of identifying and communicating with stakeholders early in the process in order to address issues or concerns that can lead to delays or changes in strategy. Understanding and recognizing these challenges and concerns during development of a comprehensive LCSM can help reduce costs and lead to a more effective and efficient resolution at an LNAPL site.
  • Section 3 – Key LNAPL Concepts
    Section 3 provides an overview of key LNAPL terminology and concepts including LNAPL behavior following a release to the subsurface (i.e., how LNAPL spreads away from the primary release point, its behavior above and below the water table, and how its migration eventually stops and naturally depletes). An understanding of these basic terms and concepts is crucial for developing a comprehensive LCSM and an effective LNAPL management plan.
  • Section 4 – LNAPL Conceptual Site Model (LCSM)
    The LCSM is a component of the overall conceptual site model (CSM), and emphasizes the concern source (i.e., the LNAPL) of the CSM. The presence of LNAPL necessitates an additional level of site understanding. The unique elements of the LCSM are presented as a series of questions for the user to answer to help build their site-specific LCSM. Ultimately, a thoroughly-developed, initial LCSM provides the basis for identifying the LNAPL concerns associated with an LNAPL release.
  • Section 5 – LNAPL Concerns, Remedial Goals, Remediation Objectives, and Remedial Technology Groups
    Section 5 describes the decision process for identifying LNAPL concerns, verifying concerns through the application of threshold metrics, establishing LNAPL remedial goals, and determining LNAPL remediation objectives. This section also introduces remedial technology groups, the concept of a treatment train approach, and how to transition between technologies to address the identified LNAPL concern(s) systematically and effectively. It is important to understand the content of this section prior to selecting and implementing an LNAPL remedial strategy.
  • Section 6 – LNAPL Remedial Technology Selection
    Section 6 describes the remedial technology screening, selection, and performance monitoring process. This section begins by identifying technologies recognized as effective for mitigating specific LNAPL concerns and achieving site-specific LNAPL remediation objectives based on the collective experience of the LNAPL Update Team. The LNAPL Technologies Appendix summarizes each of the technologies in detail and presents a systematic framework to aid the user in screening out technologies that are unlikely to be effective, ultimately leading to selection of the most appropriate technology(ies) to address the specific LNAPL concerns.

This guidance also includes relevant, state-of-the-science appendices for more detailed information on LNAPL specific topics:

  • LNAPL Technologies Appendix 
    This appendix describes in more detail each of the 21 LNAPL technologies introduced in the main document. The A-series tables describe information to evaluate the potential effectiveness of each technology for achieving LNAPL goals under site-specific conditions. Information includes the basic remediation process of each technology, the applicability of each technology to specific remedial goals, and technology-specific geologic screening factors. The B-series tables describe information to evaluate the potential implementability of each technology considering the most common site-specific factors. The C-series tables describe the minimum data requirements to make a final technology selection through bench-scale, pilot, and/or full-scale testing; they also describe metrics for tracking remedial technology performance and progress.
  • Natural Source Zone Depletion (NSZD) Appendix
    This appendix provides a technical overview of NSZD for LNAPL and the methods by which rates can be estimated and measured. It also provides a discussion of long-term LNAPL site management and how NSZD can be applied as a remedy including decision charts to support integration of NSZD and case studies demonstrating its use. For this document, the original ITRC NSZD document (ITRC LNAPL-1) was updated and incorporated into the main body and appendix.
  • Transmissivity (Tn) Appendix
    LNAPL transmissivity has application throughout the life cycle of a LNAPL project. This appendix provides an understanding of how transmissivity connects to the broader framework for LNAPL management including LNAPL recovery and mobility, and the potential for NSZD to decrease LNAPL transmissivity and mobility over time.
  • Fractured Rock Appendix
    This appendix describes the behavior and differences of how LNAPL behaves in fractured bedrock formations. While some of the same physical principles apply for multiphase flow in fractured aquifers as in porous aquifers, unique characteristics of finite and restricted fluid flow paths can lead to unexpected results in fractured settings.
  • LNAPL Sheens Appendix
    This appendix details how LNAPL sheens form, the concerns and challenges of sheens, and potential sheen mitigation technologies.

LNAPL Contamination of the Subsurface

Guidance on Characterization and Remediation of Fractured Rock

The U.S. Interstate Technology and Regulatory Council (ITRC) recently released its newest guidance document, Characterization and Remediation of Fractured Rock.  The guidance addresses significant advances in skills, tools, and lessons-learned in understanding contaminant flow and transport in fractured rock environments.  If the unique characteristics of fractured rock sites are understood, then modern tools and approaches can be applied to successfully set and meet characterization and remediation goals at these sites.

Contaminated fractured rock sites have often been considered too complex to be remediated, so site managers often default to simply containing the contamination. This guidance provides a high-level introduction to the unique puzzle faced when investigating and remediating fractured rock sites. With the new strategies and technologies presented here, fractured bedrock challenges that may have prevented site remediation in the past are now surmountable.

The guidance begins with a general discussion of fractured rock characteristics and a comparison of fractured rock and porous media CSMs. The guidance further introduces the parameters necessary for developing a fractured rock CSM and stresses the need for an experienced multidisciplinary team. The 21-Compartment Model is also introduced. This model is an adaptation of the 14-Compartment Model (Sale 2011) for unconsolidated materials. This model helps its users to visualize and understand contaminant storage, flux, and flow pathways in fractured rock.

Understanding contaminant fate and transport in fractured rock allows site managers to develop a robust CSM that can guide remediation. Specific geology and lithology and structure control the unique mechanics of fluid flow in fractured rock. In addition to these physical properties, chemical properties affect fate and transport and are equally important in developing the CSM.

This guidance details specific steps in solving the puzzle of fractured rock contaminant fate and transport, including:

  • reviewing and refining the CSM
  • defining the characterization problem
  • identifying significant data gaps
  • defining data collection objectives
  • identifying potential tools for data collection
  • developing and implementing the work plan
  • managing, interpreting, and presenting the data

A downloadable and searchable Tools Selection Worksheet is provided , which was initially used in ISC-1 (ITRC 2015b). The Tools Selection Worksheet allows users to screen for tools to address specific data needs and collect qualitative, semiquantitative or quantitative data as needed. The Tools Selection Worksheet links to detailed descriptions of all the tools and to references for further information. The guidance describes how data can be managed, interpreted, and displayed. Table 5-4 presents valuable lessons learned from real-world fractured rock characterization and remediation projects.

As a CSM nears completion, the guidance offers direction for developing remedial objectives and strategies. A table shows how to assess the different remedial strategies that may address mass stored in the compartments described in the 21-Compartment Model.

Strategies for monitoring contamination for compliance, system operation, and performance are also provided. The guidance explains how to design a monitoring well network that will provide the data needed to understand site conditions, remedy performance, and compliance.

When applied properly, mathematical models are powerful tools for understanding contaminant flow. Chapter 8 describes various model types, proper application, data needs, calibration, sensitivity, and limitations.

Finally, a discussion on stakeholder and regulatory considerations are presented, followed by a collection of case studies that demonstrate practical application of the concepts presented throughout the guidance.

Click HERE to access the document.