IN SITU CHEMICAL OXIDATION FOR REMEDIATION OF CONTAMINATED SOIL AND GROUND WATER

Subsurface contamination by organic chemicals is a widespread and serious problem at industrial, government, and military sites. IN SITU chemical oxidation wherein strong oxidants are introduced into the subsurface, has emerged as a promising IN SITU remediation method for several reasons. Chlorinated solvents, polyaromatic hydrocarbons, and other organics can be resistant to IN SITU biodegradation or may take exceedingly long periods of time in many subsurface settings. However, these organics are amenable to rapid and complete destruction by chemical oxidation and/or to partial chemical degradation as an aid to subsequent biodegradation. Also, IN SITU chemical oxidation can be implemented with relatively simple, readily available equipment and the rate and extent of treatment can enable rapid cleanup and support industrial property transfers and Brownfields redevelopment. During the past ten years, the state-of-knowledge and standard-of-practice concerning IN SITU chemical oxidation has continued to advance. This paper describes the fundamentals of chemical oxidation and its emergence as an IN SITU remediation technology. Reaction processes and delivery systems are highlighted for three common oxidant systems including hydrogen peroxide (Fenton's reagent), permanganate, and ozone. Results of research are outlined along with observations from field applications across the U.S. Field experiences have demonstrated that the successful application of IN SITU chemical oxidation requires consideration of several factors through an integrated evaluation and design practice. It is clear that matching the oxidant and IN SITU delivery system to the contaminants of concern and the site conditions is the key to successful implementation and achieving performance goals.