In situ chemical oxidation, also referred to as ISCO, is an aggressive remediation technology that has been applied to a wide range of volatile and semivolatile hazardous contaminants, including DNAPL source zones and the dissolved-phase chemicals emanating from the source zones. The 2010 Superfund Remedy Report (Thirteenth Edition) reports that ISCO was selected as a remedy at 36 Superfund sites during the period 2005 to 2008.

Chemical oxidation typically involves reduction/oxidation (redox) reactions that chemically convert hazardous compounds to nonhazardous or less toxic compounds that are more stable, less mobile, or inert. Redox reactions involve the transfer of electrons from one compound to another. Specifically, one reactant is oxidized (loses electrons) and one is reduced (gains electrons). The oxidizing agents most commonly used for treatment of hazardous contaminants in soil and groundwater are hydrogen peroxide, catalyzed hydrogen peroxide, potassium permanganate, sodium permanganate, sodium persulfate, and ozone. Each oxidant has advantages and limitations, and while applicable to soil contamination and some source zone contamination, they have been applied primarily toward remediating groundwater.

This Overview page identifies resources that provide general or introductory information about ISCO technology. The Guidance page is divided into sections for technology planning and design, performance monitoring, and regulation. Application offers case studies, beginning with links to case study databases and other compilations and then organizing individual cases by the oxidant type used: i.e., combinations of oxidants, hydrogen peroxide (including catalyzed hydrogen peroxide), ozone, permanganates, and persulfate. Training provides links to online instructional materials, and Additional Resources identifies initiatives, workshops, and interest groups that focus on ISCO technology, as well as resources for locating additional information.

General Resources

Community Guide to In Situ Chemical Oxidation
EPA 542-F-21-024, 2021

The Community Guide series (formerly Citizen's Guides) is a set of two-page fact sheets describing cleanup methods used at Superfund and other hazardous waste cleanup sites. Each guide answers six questions about the method: 1) What is it? 2) How does it work? 3) How long will it take? 4) Is it safe? 5) How might it affect me? 6) Why use it?

Engineering Issue Paper: In Situ Chemical Oxidation
EPA 600-R-06-072, 2006

This issue paper was produced by the EPA Risk Management Research Laboratory and the Engineering Forum. It provides an up-to-date overview of ISCO remediation technology and fundamentals, and is developed based on peer-reviewed literature, EPA reports, Web sources, current research, conference proceedings, and other pertinent information.

In Situ Chemical Oxidation Fact Sheet
Naval Facilities Engineering Command, 4 pp, Sep 2011

This fact sheet provides an overview of the ISCO technology, when to use it, implementation issues, lessons learned, and references for additional information.

In Situ Chemical Oxidation for Groundwater Remediation
R.L. Siegrist, M. Crimi, and T.J. Simpkin (eds.).
Springer, New York. SERDP ESTCP Environmental Remediation Technology, Vol. 3, ISBN 978-1-4419-7825-7, 678 pp, 2011

This volume provides comprehensive and up-to-date descriptions of principles and practices of ISCO for groundwater remediation. The text covers the fundamentals of chemical oxidation; the use of peroxide, permanganate, persulfate, and ozone oxidants; their reactions with contaminants of concern; and their interactions with naturally occurring subsurface materials. Attention is given to transport and fate of oxidants during use in ISCO, available mathematical models to support ISCO applications, and ISCO use in combination with other remedial technologies, such as bioremediation and MNA. The Table of Contents and sample pages are available at the publisher's website.

In Situ Chemical Oxidation: Performance, Practice, and Pitfalls
Presentation by Richard A. Brown 2003 AFCEE Technology Transfer Workshop, San Antonio, Texas

In Situ Chemical Oxidation: State of the Art
A. Tsitonaki and P.L. Bjerg. Afværgeteknologier: State of the Art, Schæffergarden, Gentofte, 22 October 2008. ATV Jord og Grundvand, Kings Lyngby, p 39-48, 2008

This paper focuses on the critical parameters for a successful ISCO application. In recent years, focus has shifted from finding out which contaminants are amenable to ISCO treatment toward overcoming implementation limitations, such as oxidant delivery, effective and timely activation, and competing reactions. Coupled approaches (treatment trains) show a promising potential for achieving higher contaminant reductions at lower remediation costs.

In Situ Oxidation
EPA Groundwater and Ecosystems Restoration Research

This Web page contains a general discussion of ISCO plus references and expert contacts.