Superfund Groundwater: Groundwater Response Technologies
Groundwater Response Technologies
The topics below include key EPA groundwater guidance and other selected reports which relate to remedial technologies. These technologies are frequently used by Superfund Remedial Project Managers (RPMs).
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On this page:
- Groundwater Treatment Technologies
- Groundwater Measurement and Monitoring Technologies
- Monitored Natural Attenuation for Groundwater
- Non-Aqueous Phase Liquids (NAPLS) and Ground Water
- Reinjection of Groundwater for Remediation
Groundwater Treatment Technologies
Guidance
Promotion of Innovative Technologies in Waste Management Programs, April 29, 1996. OSWER Policy Directive 9380.0-25, EPA publication EPA 542-F-96-012 (PDF) (12 pp, 1.15 MB)This directive describes EPA initiatives to facilitate the testing, demonstration, and use of innovative cleanup and field measurement technologies and stresses EPA's commitment to promoting environmental technology development and commercialization.
Guidance for Implementing Superfund Reform Initiative 9a: Risk Sharing, March 24, 1998. OSWER Directive 9010.02 (PDF) (6 pp, 290 K)This guidance was developed to support implementation of Superfund Reform Initiative 9a: Risk Sharing. Under this initiative, EPA agrees to share the risk of implementing innovative remediation technologies which have potential for improved performance and reduced costs.
Superfund Remedy Report (SRR)The most recent Superfund Remedy Report (SRR), Fourteenth Edition, was published by EPA in November 2013. The SRR 14th Edition summarizes remedy decisions back to 1982 with a focus on the analysis of Superfund remedial actions selected from fiscal years (FY) 2009 to 2011.The SRR compiles data on overall remedy selection and remedies for source materials (such as soil and sediments), groundwater, surface water and air related to vapor intrusion. This edition of the report, for the first time, presents a detailed look at sediment remedies and an analysis of vapor intrusion remedies. The report also analyzes media and contaminants for sites under investigation with planned RODs. The online version includes downloadable appendices that summarize all the remedy components selected for sources and groundwater in each individual decision document.
Technical Information
For technical resources concerning treatment, including technologies for groundwater cleanup, see the following websites and documents:
CLU-IN: EPA's Hazardous Waste Cleanup Information Exit
This website provides a comprehensive source of on-line and downloadable information about site remediation and field analytical technologies, including those pertaining to groundwater, developed by EPA's Technology Information and Field Services Division. In addition, users may subscribe on-line to a list server that e-mails subscribers monthly announcements of recent documents, training, and conferences related to site assessment and remediation. The website is updated daily with information of value to technology users, developers, and providers.
Remediation Technology Focus Area Exit
Through this Focus section, CLU-IN provides a compilation of the most relevant information sources on remediation technologies. These resources are presented under five categories for each technology, such as Technology Description, Applications, Engineering/Regulatory Guidance, Training and References, with a summary and direct link to each resource. Many groundwater technologies are included, such as air sparging, bioremediation, in situ chemical oxidation and reduction, phytotechnologies, permeable reactive barriers, recirculating wells, and technology applications to fractured media.
Remediation Databases Exit
Searchable information on thousands of pilot- and full-scale projects where innovative approaches have been used to deal with contamination problems.
In Situ Thermal Treatment Technologies: Lessons Learned, May 2014
The purpose of this Engineering Forum issue paper is to convey useful information gained from approximately 10 years of development and deployment of in situ thermal treatment (ISTT) technologies. This paper is the result of a series of in‐depth interviews with U.S. Environmental Protection Agency Remedial Project Managers and On‐Scene Coordinators and with ISTT vendors whose experience extends beyond federal response action sites to include state‐regulated cleanups and Brownfields/voluntary cleanups, as well as international projects.
Groundwater Measurement and Monitoring Technologies
For technical resources concerning site characterization and monitoring, including technologies for groundwater cleanup, see the following websites and documents:
CLU-IN: EPA's Hazardous Waste Cleanup Information Exit
This website provides a comprehensive source of on-line and downloadable information about site remediation and field analytical technologies, including those pertaining to groundwater, developed by EPA's Superfund program. In addition, users may subscribe on-line to a list server that e-mails subscribers monthly announcements of recent documents, training, and conferences related to site assessment and remediation. The website is updated daily with information of value to technology users, developers, and providers.
Characterization and Monitoring Technology Focus Area Exit
Through this Focus section, CLU-IN provides a compilation of the most relevant information sources on characterization and monitoring technologies for soil gas/air, sediment/soil, and groundwater. These resources are presented under several categories for each technology, such as Technology Description, Typical Uses, Theory of Operation, System Components, Mode of Operation, Target Analytes, Advantages, Limitations, Cost Data, Performance Specifications, Verification/Evaluation Reports, and Additional Information, with a summary and direct link to each resource. Examples of the types of technologies included are GC/MS, fiber optic chemical sensors, direct-push platforms (membrane interface probes, geotechnical sensors, groundwater samplers), and groundwater passive/no purge samplers. Other features include Problem SolverExit, to search tools by media and contaminant application and Ask an Expert Exit.
High-Resolution Site Characterization Exit
High-resolution site characterization (HRSC) strategies and techniques use scale-appropriate measurement and sample density to define contaminant distributions, and the physical context in which they reside, with greater certainty, supporting faster and more effective site cleanup. This website describes HRSC; how it can streamline and improve characterization efforts; how it is conducted; available support, resources and tools; case studies; practitioner forums; publications; training offerings; and archived training presentations.
Site Characterization Technologies for DNAPL Investigations, EPA542-R-04-017, September 2004
This report summarizes information on the current state of technologies available for locating and characterizing dense non-aqueous phase liquid (DNAPL) contaminated sites. This document is intended to help managers at sites with potential or confirmed DNAPL contamination identify suitable characterization technologies, screen the technologies for potential application, learn about applications at similar sites, and locate additional information on these technologies.
Groundwater Issue: Low-Flow (Minimal Drawdown) Groundwater Sampling Procedures, April 1996, OSWER Publication EPA540-S-95-504
This report provides background information on the development of low-flow sampling procedures and its application under a variety of hydrogeologic settings. It is intended to support the production of standard operating procedures for use by EPA Regional personnel and other environmental professionals engaged in groundwater sampling.
Methods for Monitoring Pump-and-Treat Performance, June 1994, EPA/600/R-94/123 (PDF) (111 pp, 2.1 MB)
This publication provides guidance for monitoring the effectiveness and efficiency of pump-and-treat remediation systems, with emphasis on the "pump" part of the technology rather than chemical enhancements. The report includes sections on monitoring hydraulic containment, monitoring groundwater restoration, evaluating restoration success/closure, a case study, and references. It includes performance criteria, monitoring objectives, and protocols for evaluating effectiveness of containment and restoration systems. From the Office of Research and Development Publication EPA/600/R-94/123, NTIS Order Number PB95-125456.
Monitored Natural Attenuation
Guidance
Use of Monitored Natural Attenuation for Inorganic Contaminants in Groundwater at Superfund Sites, Final OSWER Directive 9283.1-36, August 2015 (PDF) (83 pp, 1.3 MB)
This new monitored natural attenuation (MNA) policy document for inorganic contaminants ("2015 MNA guidance") expands on and is designed to be a companion to the 1999 MNA guidance. Together, these two policy documents provide guidance on the consideration of MNA for a broad range of contaminants at Superfund sites. This 2015 MNA guidance, consistent with the 1999 MNA guidance, indicates that multiple "lines of evidence" should be obtained to evaluate whether MNA should be considered as part of the site's selected response action. As a related matter, the 1999 MNA guidance also recommends use of a tiered analysis approach for considering MNA, which typically involves a detailed analysis of site characteristics that control and sustain attenuation. The 2015 MNA guidance builds on this tiered approach and recommends a phased analytical approach tailored specifically for inorganic contaminants.
Use of Monitored Natural Attenuation at Superfund, RCRA Corrective Action, and Underground Storage Tank Sites, Final OSWER Directive, Publication EPA/540/R-99/009. April 1999 (PDF) (39 pp, 1.9 MB)
This directive clarifies EPA's policy regarding the use of monitored natural attenuation (MNA) for the remediation of contaminated soil and groundwater. It defines the term "monitored natural attenuation" and explains that EPA considers it a remedy, not a "no action" alternative. The directive outlines potential advantages and disadvantages of this remedy, under what conditions it should be selected, the type of site most suitable for this remedy choice, the site data required to support the decision, performance monitoring considerations, and the use of contingency remedies. The directive also has a lengthy bibliography, including EPA web sites with information on monitored natural attenuation.
Technical Information
Monitored Natural Attenuation of Inorganic Contaminants in Groundwater Reports
Set of three volumes that address the technical basis and requirements for assessing the potential applicability of MNA as part of a groundwater remedy for plumes with non-radionuclide and/or radionuclide inorganic contaminants.
- Volume 1 - Technical Basis for Assessment
This document represents the first volume of a set of three volumes that address the technical basis and requirements for assessing the potential applicability of MNA as part of a ground-water remedy for plumes with non-radionuclide and/or radionuclide inorganic contaminants. Volume 1, titled "Technical Basis for Assessment," consists of three sections that describe 1) the conceptual background for natural attenuation for inorganic contaminants, 2) the technical basis for attenuation of inorganic contaminants in ground water, and 3) approaches to site characterization to support evaluation of MNA. Emphasis is placed on characterization of immobilization and/or transformation processes that may control contaminant attenuation, as well as technical approaches to assess performance characteristics of the MNA remedy. A tiered analysis approach is presented to assist in organizing site characterization tasks in a manner designed to reduce uncertainty in remedy selection.
- Volume 2 - Assessment for Non-Radionuclides Including Arsenic, Cadmium, Chromium, Copper, Lead, Nickel, Nitrate, Perchlorate, and Selenium
This document represents the second volume of a set of three volumes that address the technical basis and requirements for assessing the potential applicability of MNA as part of a ground-water remedy for plumes with non-radionuclide and/or radionuclide inorganic contaminants. Volume 2, titled "Assessment for Non-Radionuclides Including Arsenic, Cadmium, Chromium, Copper, Lead, Nickel, Nitrate, Perchlorate, and Selenium," consists of individual chapters that describe 1) the natural processes that may result in the attenuation of the listed contaminants and 2) data requirements to be met during site characterization. Emphasis is placed on characterization of immobilization and/or transformation processes that may control contaminant attenuation, as well as technical approaches to assess performance characteristics of the MNA remedy. A tiered analysis approach is presented to assist in organizing site characterization tasks.
- Volume 3 - Assessment for Radionuclides Including Tritium, Radon, Strontium, Technetium, Uranium, Iodine, Radium, Thorium, Cesium, and Plutonium-Americium
This document represents the third volume of a set of three volumes that address the technical basis and requirements for assessing the potential applicability of MNA as part of a ground-water remedy for plumes with non-radionuclide and/or radionuclide inorganic contaminants. Volume 3, titled "Assessment for Radionuclides Including Tritium, Radon, Strontium, Technetium, Uranium, Iodine, Radium, Thorium, Cesium, and Plutonium-Americium," consists of individual chapters that describe 1) the natural processes that may result in the attenuation of the listed contaminants and 2) data requirements to be met during site characterization. Emphasis is placed on characterization of immobilization and/or radioactive decay processes that may control contaminant attenuation, as well as technical approaches to assess performance characteristics of the MNA remedy. A tiered analysis approach is presented to assist in organizing site characterization tasks.
Performance Monitoring of MNA Remedies for VOCs in Groundwater, OSWER 9355.4-25. EPA540-R-03-004, September 2003, [Also EPA/600/R-04/027, April 2004]
This report identifies data needs and evaluation methods useful for monitoring the performance of MNA remedies selected for VOCs in groundwater. The document discusses the design considerations for monitoring networks and methods for determining remedy effectiveness. Effective monitoring of natural attenuation processes involves a three-dimensional approach to network design and clearly defined performance criteria based on site-specific remedial action objectives. Objectives for the monitoring program will be met through routine evaluations of institutional controls and measurements of contaminant, geochemical, and hydrologic parameters. These data are used to evaluate changes in three-dimensional plume boundaries, contaminant mass and concentration, and hydrological and geochemical changes that may indicate changes in remedy performance.
Technical Protocol for Evaluating Natural Attenuation of Chlorinated Solvents in Groundwater, Office of Research and Development, EPA600-R-98-128, September 1998 (PDF) (248 pp, 5.6 MB)
This protocol provides guidance for environmental managers on the steps that must be taken to understand the rate and extent to which natural processes are reducing contaminant concentrations at sites that are contaminated by chlorinated solvents. The document identifies parameters that are useful in the evaluation of natural attenuation of chlorinated solvents (chlorinated aliphatic hydrocarbons and/or fuel hydrocarbons) and provides recommendations to analyze and interpret the data collected from the site characterization process. It also provides suggestions for integrating monitored natural attenuation (MNA) into an integrated approach to remediation that also includes an active remedy. It includes a useful list of definitions of terms related to the topic. It is a technical, not a policy, document. Data gathered using this protocol can be used to evaluate whether MNA by itself or in conjunction with other technologies is sufficient to achieve site remedial objectives, and to compare the relative effectiveness of MNA and other remedial methods. This protocol is the result of a collaborative field and laboratory research effort involving researchers from EPA's Office of Research and Development, the U.S. Air Force, and the U.S. Geological Survey.
Non-Aqueous Phase Liquids (NAPLS) and Groundwater
Guidance
Clarification of OSWER's 1995 Technical Impracticability Waiver Policy, OSWER Directive 9355.5-32, September 2011 (PDF) (4 pp, 764 K)
The purpose of this memorandum is to provide clarification to the memorandum titled, Superfund Groundwater RODs: Implementing Change This Fiscal Year, July 31, 1995, (OSWER Directive 9335.3-03P) regarding the use of Technical Impracticability (TI) waivers at Comprehensive Environmental Response Compensation and Liability Act (CERCLA) sites with Dense Non-Aqueous Phase Liquid (DNAPL) contamination.
Considerations in Groundwater Remediation at Superfund Sites and RCRA Facilities-Update, OSWER Directive 9283.1-06, May 1992 (PDF) (13 pp, 76 K)
This directive clarifies and expands OSWER's 1989 directive "Considerations in Groundwater Remediation at Superfund Sites" (see "remedy selection"), especially with regard to non-aqueous phase liquid (NAPL) contaminants. The directive recommends: that the likelihood of NAPL contamination, especially dense NAPLs (DNAPLs), should be evaluated as early as possible; where NAPLs are likely, the potential nature and extent of contamination should be characterized to determine appropriate remedial actions; further contamination (dissolved or NAPL) migration should be minimized by using early response actions; early actions should be coordinated with later actions in a phased approach; and groundwater cleanup actions should be designed to include careful monitoring and provisions for modifying them over time to improve their effectiveness. For sites where it can be demonstrated to EPA that achieving cleanup standards is technically impracticable, EPA may issue a waiver for Superfund sites or modify the permit or enforcement order for RCRA facilities. For these cases, EPA will determine alternative remedial objectives that protect human health and the environment.
Presumptive Response Strategy and Ex-Situ Treatment Technologies for Contaminated Groundwater at CERCLA Sites, Final Guidance, OSWER Publication 9283.1-12, EPA540-R-96-023, October 1996 (PDF) (86 pp, 779 K)
This guidance outlines the "phased approach" strategy for addressing contaminated groundwater. The strategy integrates the site characterization, early actions, remedy selection, design, implementation, and performance monitoring phases. The strategy emphasizes ways to select achievable remedial objectives and ways to optimize the selected remedy so that it is more effective, less costly, and takes less time. The guidance also identifies presumptive technologies for treatment of extracted groundwater, which are to be used to streamline the Feasibility Study for sites which evaluate pump and treat.
Estimating Potential for Occurrence of DNAPL at Superfund Sites, January 1992. OSWER Publication 9355.4-07FS (PDF) (10 pp, 470 K)
The presence of DNAPL in soils and aquifers can control the ultimate success or failure of remediation at a site, but because of the complex nature of DNAPL transport and fate, it may often be undetected by direct methods. This fact sheet provides a guide for estimating the potential for the presence of dense non-aqueous phase liquids (DNAPLs) at a site based on historical site use information and site characterization data. It summarizes the definition of DNAPL and presents five conceptual models for its release and presence at sites. It includes a series of flow charts for deciding whether a site has a high, moderate, or low potential for containing DNAPL. It also includes step by step worksheets for calculating effective solubility of single-component DNAPL and for assessing the likelihood of DNAPL presence based on organic concentrations in soil samples; and a glossary of terms related to DNAPLs.
Technical Information
DNAPL Focus Area Exit
Through this Focus section, CLU-IN provides a compilation of the most relevant information sources on major classes of DNAPL (i.e., ethers, halogenated alkanes, halogenated alkenes, halogenated monoaromatics, polychlorinated biphenyls (PCBs), multi-component waste (coal tars, creosotes, and heavy oils) and other (e.g., aniline, benzyl chloride). These resources are presented under several categories: Overview, Policy and Guidance, Chemistry and Behavior, Environmental Occurrence, Toxicology, Detection and Site Characterization, Treatment Technologies, Conferences and Seminars, and Additional Resources, with a summary and direct link to each resource.
DNAPL Remediation: Selected Projects Where Regulatory Closure Goals Have Been Achieved, EPA 542-R-09-008, August 2009 (PDF) (52 pp, 1.5 MB)
The purpose of this paper is to highlight sites where dense nonaqueous phase liquid (DNAPL) source reduction has been demonstrated as an aid in meeting regulatory cleanup goals. The presence of DNAPL in the subsurface can serve as a long-term source of dissolved contaminant plumes in groundwater, making it more difficult to reach regulatory closure. However, once the DNAPL source is addressed, residual groundwater plumes may be more amenable to treatment, including less aggressive techniques such as monitored natural attenuation (MNA) or bioremediation. This paper updates the document, DNAPL Remediation: Selected Projects Approaching Regulatory Closure, prepared in 2004 by providing more recent information on technologies and on five additional selected sites at which DNAPL source reduction technologies were applied.
Site Characterization Technologies for DNAPL Investigations, EPA542-R-04-017, September 2004
This report summarizes information on the current state of technologies available for locating and characterizing dense non-aqueous phase liquid (DNAPL) contaminated sites. This document is intended to help managers at sites with potential or confirmed DNAPL contamination identify suitable characterization technologies, screen the technologies for potential application, learn about applications at similar sites, and locate additional information on these technologies.
The DNAPL Remediation Challenge: Is There a Case for Source Depletion? Office of Research and Development, EPA600-R-03-143, December 2003
This report contains the findings and recommendations of a panel of national and international scientists and engineers selected by EPA's Office of Research and Development, National Risk Management Research Laboratory (ORD/NRMRL). All members are recognized authorities on the topic of DNAPL remediation. The panel was asked to conduct a critical, independent review of the current state of the science regarding difficulties and benefits associated with remediation of DNAPL source zones and research needs to address this important environmental challenge. The report presents the views of the panel and does not necessarily represent Agency views or policies.
Groundwater Issue: Light Nonaqueous Phase Liquids, ORD and OSWER joint publication EPA540-S-95-500, July 1995
This issue paper from the Technical Support Project discusses light nonaqueous phase liquids (LNAPLs), or NAPL which has a density less than water. The paper summarizes LNAPL fate and transport and remediation technologies of use for LNAPL recovery. It includes a table of the physical properties of chemical compounds most prevalent at Superfund sites which have a specific gravity less than water.
DNAPL Site Characterization: Quick Reference Fact Sheet, OSWER Publication 9355.4-16FS, EPA540-F-94-049, September 1994 (PDF) (12 pp, 685 K)
This fact sheet provides a strategy for the investigation of dense non-aqueous phase liquids (DNAPLs) at sites, including a flow chart of suggested activities and suggestions on site conceptualization and objectives. It also summarizes noninvasive and invasive field methods for DNAPL characterization and provides a table summarizing how one might determine, infer or suspect DNAPL presence at a site.
Evaluation of the Likelihood of DNAPL Presence at NPL Sites, National Results, OSWER Publication 9355.4-13, EPA540-R-93-073, September 1993 (PDF) (114 pp, 1.1 MB)
This publication presents the results of a survey of 712 National Priority List (NPL) sites to estimate the proportion of NPL sites where dense non-aqueous phase liquids (DNAPLs) may be present. The project also assessed the usefulness of various indirect indicators of DNAPL presence associated with historical site information and groundwater contaminant information.
Groundwater Issue: Dense Nonaqueous Liquids, ORD and OSWER joint publication EPA540-4-91-002, March 1991
This issue paper of the Technology Support Project provides an overview from a conceptual fate and transport point of view, of DNAPL phase distribution, monitoring, site characterization, remediation, and modeling. It includes a table of the physical properties of chemical compounds most prevalent at Superfund sites which have a specific gravity greater than water.
Reinjection of Groundwater
Applicability of RCRA Section 3020 to In-Situ Treatment of Groundwater, Exit December 27, 2000, OSWER/OSW Memorandum (PDF) (6 pp, 388 K)
Attachment: Applicability of Land Disposal Restrictions to RCRA and CERCLA Ground Water Treatment Reinjection Superfund Management Review: Recommendation No. 26 December 27, 1989. OSWER Directive 9234.1-06 (PDF) (3 pp, 317 K)
This memorandum clarifies that reinjection of treated groundwater to promote in-situ treatment is allowed under section 3020(b) as long as certain conditions are met. Specifically, the groundwater must be treated prior to reinjection; the treatment must be intended to substantially reduce hazardous constituents in the groundwater - either before or after reinjection; the cleanup must be protective of human health and the environment; and the injection must be part of a response action under CERCLA section 104 or 106 or a RCRA corrective action intended to clean up the contamination.
Applicability of Land Disposal Restrictions to RCRA and CERCLA Groundwater Treatment Reinjection Superfund Management Review: Recommendation No. 26 December 27, 1989. OSWER Directive 9234.1-06 (PDF) (3 pp, 317 K)
This memorandum explains EPA's interpretation of whether the RCRA land disposal restrictions (LDRs) are applicable or (under CERCLA response actions only) relevant and appropriate to such reinjections or to the remediation as a whole. There has been some question as to whether groundwater contaminated with restricted RCRA hazardous wastes, which is extracted during a RCRA corrective action or CERCLA response action, must meet the best demonstrated available technology (BDAT) identified for that waste under the RCRA LDRs prior to each reinjection, in a pump-and-treat reinjection remediation system.