Groundwater Technologies

Superfund groundwater cleanup technologies and strategies have evolved since the program’s inception in 1980. Initially, groundwater pump and treat was the primary technology and strategy used, often as the only groundwater remedial approach. Over the years, new groundwater treatment technologies and approaches have become available allowing flexibility in how cleanup goals can be achieved. The following section provides guidance and technical information on groundwater remediation and measurement technology.

On this page:

Groundwater Remediation Technologies and Techniques
Groundwater Measurement and Monitoring Technologies and Techniques
Monitored Natural Attenuation for Groundwater
Non-Aqueous Phase Liquids (NAPLS) and Groundwater
Reinjection of Groundwater for Remediation

Groundwater Remediation Technologies and Techniques

The following section provides guidance and technical information on the technologies and techniques for treating contaminated groundwater.

Guidance

Promotion of Innovative Technologies in Waste Management Programs (PDF)(12 pp, 1.2 MB)
April 1996, OSWER Policy Directive 9380.0-25, EPA 542-F-96-012

This directive describes EPA initiatives to facilitate the testing, demonstration and use of innovative cleanup and field measurement technologies. It stresses EPA's commitment to promoting environmental technology development and commercialization.

Guidance for Implementing Superfund Reform Initiative 9a: Risk Sharing (PDF)(6 pp, 290 K)
March 1998, OSWER Directive 9010.02

EPA developed this guidance to support implementation of Superfund Reform Initiative 9a: Risk Sharing. Under this initiative, EPA agrees to share the risk of implementing innovative remediation technologies that can improve performance and reduce costs.

Superfund Remedy Report

Once every three years, EPA prepares the Superfund Remedy Report to provide information and analyses on remedies EPA selected to address contamination, including groundwater contamination, at Superfund National Priorities List and Superfund Alternative Approach sites. The latest report, the 16^th edition, compiles and analyzes Superfund remedial actions selected in fiscal years (FYs) 2015, 2016 and 2017, and provides trends since FY 1982.

Technical Information

For technical resources concerning remediation, including technologies for groundwater cleanup, see the following websites and documents:

CLU-IN: EPA's Hazardous Waste Cleanup Information
CLU-IN provides a comprehensive source of information about site characterization and remediation technologies and techniques, including those pertaining to groundwater. Users may subscribe to receive a monthly email that announces recent documents, training and conferences related to site assessment and remediation.

Remediation Technology Focus Area
Through this focus area, CLU-IN provides information on remediation technologies and techniques. Many groundwater technologies are included.

Remedial Technology Fact Sheet — Activated Carbon-Based Technology for In Situ Remediation (PDF)(9 pp, 915 K)
April 2018, EPA 542-F-18-001

This fact sheet provides information to practitioners and regulators on science and current practice of activated carbon-based remedial technologies for in situ applications.

Examples of Groundwater Remediation at NPL Sites (PDF)(114 pp, 2.7 MB)
May 2018, EPA 542-R-18-002

This report highlights some National Priorities List sites where EPA has used innovative and established technologies to restore groundwater for use as drinking water.

In Situ Treatment Performance Monitoring: Issues and Best Practices (PDF)(15 pp, 2 MB)
April 2018, EPA 542-F-18-002

This document discusses issues that are likely to occur in monitoring wells during and after active in situ treatment at contaminated sites. The paper discusses potential sampling and analytical issues, highlights the mechanisms and impacts on performance monitoring, and provides best practices.

In Situ Thermal Treatment Technologies: Lessons Learned (PDF)(46 pp, 8.7 MB)
May 2014

This engineering paper summarizes information from 10 years of development and deployment of in situ thermal treatment (ISTT) technologies based on in‐depth interviews with USEPA staff and ISTT vendors whose experience extends beyond federal response action sites.

Ground Water Sample Preservation at In-Situ Chemical Oxidation Sites: Recommended Guidelines (PDF)(16 pp, 620 K)
August 2012, EPA 600-R-12-049

This paper provides background information, general guidelines, and specifics for methods and procedures that can be used to detect whether an oxidant (permanganate or persulfate) is present in groundwater, to approximate the oxidant concentration, and to estimate and deliver the volume or mass of preservative required to preserve the binary mixture groundwater sample.

A Systematic Approach for Evaluation of Capture Zones at Pump and Treat Systems (PDF)(166 pp, 20 MB)
January 2008, EPA 600-R-08-003

This document describes a systematic approach for performing capture zone analysis associated with groundwater pump-and-treat systems. This analysis is meant to determine the zone of hydraulic control of a pump-and-treat system.

Options for Discharging Treated Water from Pump and Treat Systems (PDF)(23 pp, 355 K)
May 2007, EPA542-R-07-006

This fact sheet presents information on available options for the discharge of water that results from a P&T remedy.

Engineering Issue Paper: In-Situ Chemical Oxidation (PDF)(60 pp, 1.2 MB)
August 2006, EPA600-R-06-072

This paper, produced by the EPA Risk Management Research Laboratory and the Engineering Forum, provides an overview of in-situ chemical oxidation remediation technologies and fundamentals.

Cost-Effective Design of Pump and Treat Systems (PDF)(38 pp, 423 K)
April 2005, EPA542-R-05-008

This fact sheet summarizes key aspects to consider for designing cost-effective pump and treat systems. Topics include remedy goals and performance monitoring, system design parameters, extraction system considerations, appropriate treatment technologies, discharge options, and system controls.

Evaluation of Subsurface Engineered Barriers at Waste Sites (PDF)(148 pp, 1.7 MB), Volume 2, Appendix B (PDF)(244 pp, 15.5 MB)
August 1998, EPA 542-R-98-005

This report provides a national retrospective analysis of subsurface barrier field performance and information on the use and evaluation of barrier systems.

Pump-And-Treat Ground-Water Remediation: A Guide for Decision Makers and Practitioners (PDF)(90 pp, 2.8 MB)
July 1996, Office of Research and Development, EPA/625/R-95/005

This guide is an introduction to pump-and-treat groundwater remediation. It presents decisionmakers with a foundation for evaluating the appropriateness of conventional or innovative approaches to pump and treat, including when it is an appropriate remediation approach, effective application, how to anticipate tailing and rebound, and recommended methods for effective hydraulic containment.

Ground Water Forum Website

This website contains publications on various groundwater issues developed by the Ground Water Forum, a network of EPA remedial project managers, corrective action staff, on-scene coordinators and research scientists.

Groundwater Measurement and Monitoring Technologies

The following section provides technical resources for site characterization and monitoring at sites requiring groundwater cleanup.

Characterization and Monitoring Technology Focus Area
CLU-IN provides information in this focus area on characterization and monitoring technologies for soil gas/air, sediment, soil and groundwater. Examples of the types of technologies included are gas chromatograph-mass spectrometer, fiberoptic chemical sensors, direct-push platforms, and groundwater passive/no purge samplers.

High-Resolution Site Characterization
High-resolution site characterization (HRSC) strategies and techniques use scale-appropriate measurement and sample density to define with greater certainty contaminant distributions and their surrounding environment. 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
September 2004, EPA 542-R-04-017

This report summarizes information on the state of technologies available for locating and characterizing dense non-aqueous phase liquid (DNAPL) contaminated sites.

Groundwater Sampling and Monitoring with Direct Push Technologies
August 2005, OSWER Publication 9200.1-51, EPA 540/R-04/005

This guidance clarifies how direct push technologies can be used to meet a variety of data quality requirements for a variety of site conditions. This document focuses on related groundwater sampling issues, particularly those regarding the quality and usability of groundwater data.

Ground-Water Sampling Guidelines for Superfund and RCRA Project Managers (PDF)(53 pp, 639 K)
May 2002, EPA 542-S-02-001

This document, developed by the Ground Water Forum, provides sampling guidelines primarily for groundwater monitoring wells that have a screen or open interval with a length of 10 feet or less and which can accept a sampling device. Procedures that minimize disturbance to the aquifer will yield the most representative groundwater samples. This document provides a summary of current and/or recommended groundwater sampling procedures.

Groundwater Issue: Low-Flow (Minimal Drawdown) Groundwater Sampling Procedures (PDF)(12 pp, 79 K)
April 1996, EPA 540-S-95-504

This Ground Water Forum report provides information on the development of low-flow sampling procedures and its application under a variety of hydrogeologic settings.

Methods for Monitoring Pump-and-Treat Performance (PDF)(111 pp, 2.1 MB)
June 1994, EPA/600/R-94/123

This publication provides guidance for monitoring the effectiveness and efficiency of pump-and-treat remediation systems.

Monitored Natural Attenuation

Depending on site conditions and cleanup goals, response actions may include “active” treatment or “less active” approaches. For certain sites, monitored natural attenuation, which relies on natural processes that decrease or attenuate soil and groundwater contaminant concentrations, may be used to complement or as an alternative to pump-and-treat or other active technologies. The following section provides guidance and technical information on monitored natural attenuation.

Guidance

Use of Monitored Natural Attenuation for Inorganic Contaminants in Groundwater at Superfund Sites (PDF)(83 pp, 1.3 MB)
August 2015, OSWER Directive 9283.1-36

This policy document expands on and is a companion to the 1999 monitored natural attenuation (MNA) guidance referenced directly below. Together, these two policy documents provide guidance on the consideration of MNA for a broad range of contaminants at Superfund sites. The 2015 MNA guidance recommends a phased analytical approach tailored to inorganic contaminants.

Use of Monitored Natural Attenuation at Superfund, RCRA Corrective Action, and Underground Storage Tank Sites (PDF)(39 pp, 1.9 MB)
April 1999, OSWER Directive 9200.4-17P, EPA 540/R-99/009

This directive clarifies EPA's policy regarding the use of MNA for the remediation of contaminated soil and groundwater. It outlines potential advantages and disadvantages of this remedy, the conditions under which it should be selected, the type of site most suitable for this remedy, the site data required to support the decision, performance monitoring considerations, and the use of contingency remedies.

Technical Information

Monitored Natural Attenuation of Inorganic Contaminants in Ground Water, Volume 1: Technical Basis for Assessment, Office of Research and Development (PDF)(94 pp, 2.5 MB)
October 2007, EPA 600-R-04-027

This document is the first volume of three reports that address assessing the potential applicability of MNA as part of a groundwater remedy for plumes with non-radionuclide and/or radionuclide inorganic contaminants. This volume describes 1) the conceptual background for natural attenuation for inorganic contaminants, 2) the technical basis for attenuation of inorganic contaminants in groundwater, and 3) approaches to site characterization to support evaluation of MNA.

Monitored Natural Attenuation of Inorganic Contaminants in Ground Water, Volume 2: Assessment for Non-Radionuclides Including Arsenic, Cadmium, Chromium, Copper, Lead, Nickel, Nitrate, Perchlorate, and Selenium (PDF)(124 pp, 2 MB)
October 2007, EPA 600-R-07-140

This document is the second of three reports that address assessing the potential applicability of MNA as part of a groundwater remedy for plumes with non-radionuclide and/or radionuclide inorganic contaminants. This volume describes the natural processes that may result in the attenuation of the listed contaminants and data requirements to be met during site characterization. A tiered analysis approach is presented to assist in organizing site characterization tasks.

Monitored Natural Attenuation of Inorganic Contaminants in Ground Water, Volume 3: Assessment for Radionuclides Including Tritium, Radon, Strontium, Technetium, Uranium, Iodine, Radium, Thorium, Cesium, and Plutonium-Americium (PDF)(147 pp, 7.1 MB)
September 2010, EPA 600-R-10-093

This document is the third volume of a set of three reports that address assessing the potential applicability of MNA as part of a groundwater remedy for plumes with non-radionuclide and/or radionuclide inorganic contaminants. This volume describes the natural processes that may result in the attenuation of the listed contaminants and data requirements to be met during site characterization.

Performance Monitoring of MNA Remedies for VOCs in Groundwater (PDF)(96 pp, 1.8 MB)
September 2003, OSWER 9355.4-25, EPA540-R-03-004
[Also issued as EPA/600/R-04/027 in April 2004]

This report identifies data needs and evaluation methods useful for monitoring the performance of MNA remedies selected for volatile organic compounds (VOCs) in groundwater.

Technical Protocol for Evaluating Natural Attenuation of Chlorinated Solvents in Groundwater (PDF)(248 pp, 5.6 MB)
September 1998, EPA 600-R-98-128

This protocol describes the steps to understanding the rate and extent to which natural processes are reducing contaminant concentrations at sites contaminated with mixtures of chlorinated solvents and fuel hydrocarbons. Data gathered using this protocol can be used to evaluate whether MNA by itself or with other technologies is sufficient to achieve site remedial objectives, and to compare the relative effectiveness of MNA and other remedial methods.

Non-Aqueous Phase Liquids (NAPLS) and Groundwater

NAPLs are compounds that are resistant to mixing with water. As such, they dissolve slowly, supplying potentially significant concentrations of contaminants to groundwater over very long time periods. Therefore, the presence of NAPLs will have a significant influence on the time frame required or likelihood of achieving cleanup standards, and should be evaluated when selecting appropriate remedial actions. The following section provides guidance and technical information on NAPLS and groundwater.

Guidance

Clarification of OSWER's 1995 Technical Impracticability Waiver Policy (PDF)(4 pp, 764 K)
September 2011, OSWER Directive 9355.5-32

This memorandum clarifies the memorandum, “Superfund Groundwater RODs: Implementing Change This Fiscal Year, July 31, 1995,” (OSWER Directive 9335.3-03P) regarding the use of technical impracticability waivers at sites with dense non-aqueous phase liquid (DNAPL) contamination.

Considerations in Groundwater Remediation at Superfund Sites and RCRA Facilities — Update (PDF)(13 pp, 76 K)
May 1992, OSWER Directive 9283.1-06

This directive clarifies and expands OSWER's 1989 directive "Considerations in Groundwater Remediation at Superfund Sites" (see "remedy selection"), especially regarding non-aqueous phase liquid (NAPL) contaminants.

Presumptive Response Strategy and Ex-Situ Treatment Technologies for Contaminated Groundwater at CERCLA Sites (PDF)(86 pp, 779 K)
October 1996, OSWER Publication 9283.1-12, EPA 540-R-96-023

This guidance outlines the "phased approach" for addressing contaminated groundwater. The guidance also identifies presumptive technologies for treatment of extracted groundwater, which can be used to streamline the feasibility study for sites that evaluate pump and treat.

Estimating Potential for Occurrence of DNAPL at Superfund Sites (PDF)(10 pp, 470 K)
January 1992, OSWER Publication 9355.4-07FS

This fact sheet provides a guide for estimating the potential for the presence of DNAPLs at a site based on historical site use information and characterization data.

Technical Information

DNAPL Focus Area

Through this Focus section, CLU-IN provides a compilation of information sources on major classes of DNAPL.

Integrated DNAPL Site Characterization and Tools Selection, ITRC, 2015

This document describes the critical concepts related to DNAPL behavior and characterization approaches and tools for collecting subsurface data at DNAPL sites.

DNAPL Remediation: Selected Projects Where Regulatory Closure Goals Have Been Achieved (PDF)(52 pp, 1.5 MB)
August 2009, EPA 542-R-09-008

This paper highlights sites where DNAPL source reduction has been demonstrated to help meet regulatory cleanup goals. This paper updates the document, “DNAPL Remediation: Selected Projects Approaching Regulatory Closure,” prepared in 2004.

Site Characterization Technologies for DNAPL Investigations (PDF)(165 pp, 3 MB)
September 2004, EPA 542-R-04-017

This report summarizes information on the state of technologies in 2004 available for locating and characterizing DNAPL-contaminated sites.

The DNAPL Remediation Challenge: Is There a Case for Source Depletion? (PDF)(129 pp, 1.3 MB)
December 2003, EPA 600-R-03-143

This report contains the findings and recommendations of a panel of national and international scientists and engineers EPA selected for their expertise in DNAPL remediation. The panel was asked to conduct an independent review of the state of the science regarding difficulties of and benefits associated with remediation of DNAPL source zones. The report also discusses research needs. It presents the views of the panel, not necessarily those of the Agency.

Groundwater Issue: Light Nonaqueous Phase Liquids (PDF)(28 pp, 630 K)
July 1995, EPA 540-S-95-500

This Ground Water Forum issue paper summarizes light nonaqueous phase liquid (LNAPL) fate and transport and remediation technologies.

DNAPL Site Characterization: Quick Reference Fact Sheet (PDF)(12 pp, 685 K)
September 1994, OSWER Publication 9355.4-16FS, EPA 540-F-94-049

This fact sheet provides a strategy for investigating DNAPLs at contaminated sites.

Evaluation of the Likelihood of DNAPL Presence at NPL Sites, National Results (PDF)(114 pp, 1.1 MB)
September 1993, OSWER Publication 9355.4-13, EPA 540-R-93-073

This publication presents the results of a survey of 712 NPL sites to estimate the proportion where 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 (PDF)(21 pp, 673 K)
March 1991, EPA 540-4-91-002

This Ground Water Forum issue paper provides an overview of DNAPL phase distribution, monitoring, site characterization, remediation and modeling.

Reinjection of Groundwater

The following section provides guidance on the reinjection of treated groundwater as part of a CERCLA response action.

Applicability of RCRA Section 3020 to In-Situ Treatment of Groundwater (PDF)(6 pp, 388 K)
December 2000, OSWER/OSW Memorandum
Attachment: Applicability of Land Disposal Restrictions to RCRA and CERCLA Ground Water Treatment Reinjection Superfund Management Review: Recommendation No. 26 (PDF)(3 pp, 317 K)
December 1989, OSWER Directive 9234.1-06

This memorandum clarifies that reinjection of treated groundwater to promote in situ treatment is allowed under RCRA section 3020(b) if certain conditions are met.

Applicability of Land Disposal Restrictions to RCRA and CERCLA Ground Water Treatment Reinjection Superfund Management Review: Recommendation No. 26 (PDF)(3 pp, 317 K)
December 1989, OSWER Directive 9234.1-06

This memorandum explains EPA's interpretation of whether the RCRA land disposal restrictions are applicable or (under CERCLA response actions only) relevant and appropriate to such reinjections or to the remediation as a whole.

Protecting Underground Sources of Drinking Water from Underground Injection (UIC)

This EPA website contains information for owners and operators of injection wells, regulators and the public about safe injection well operations to prevent the contamination of underground sources of drinking water.