REMEDIATION SECTION
Remediation of VOCs Using
Potassium Permanganate

There are no silver bullets…but Potassium Permanganate can hit your target at sites contaminated with Volatile Organic Compounds (VOCs).

INTRODUCTION
Within the last year, the use of potassium permanganate (KMnO4) to oxidize or chemically degrade VOCs in soil and ground water has gained acceptance from regulators, site owners and operators, and environmental engineers and consultants. Although KMnO4 has been used for many years to destroy alkenes, alcohols, amines, and sulfur- and nitrogen-containing, odor-generating compounds in industrial wastewater, the contaminants most often targeted during environmental remediation are chlorinated solvents, such as trichloroethylene (TCE), tetrachloroethylene (perchloroethylene or PCE), other chlorinated solvents, and vinyl chloride. Potassium permanganate solutions can remediate VOC-contaminated soil or ground water, either in-situ or ex-situ.

BASIS
Potassium permanganate primarily attacks double bonds within the targeted chemicals, splitting it into two smaller and less-objectionable compounds. Degradation of these secondary compounds may occur depending, primarily, on their stability and structure, the concentration of KMnO4, and the pH of the media. The importance of a double bond within the contaminant limits the number of contaminants that can be oxidized. But TCE, PCE, vinyl chloride, and other susceptible compounds are at the root of the majority of the largest and most hazardous ground water plumes.

PRACTICAL CONSIDERATIONS
Potassium permanganate is easy to use. A solid at room temperature, it dissolves easily in water, with a maximum field solubility of approximately 5% by weight. At high concentrations, it can degrade certain materials (e.g. plastics, metals, rubber, etc.). However, it is less aggressive than hydrogen peroxide or ozone, therefore the capital cost of similarly sized remedial systems would be less. It also is more stable (i.e. more apt to react with contaminants rather than with naturally present materials or to spontaneously decay) than these compounds. This longer-life means it can typically travel further from its point of application during in-situ projects, therefore the operating costs are usually less for comparable projects. But all these theoretical assets mean little. What has been accomplished? In laboratory treatability tests, a 4% by weight solution of KMnO4 reduced initial TCE concentrations by over 96%. In contrast, twice as much hydrogen peroxide by weight reduced TCE 40.4% and the same amount of hydrogen peroxide with iron sulfate reduced TCE 72.5%. In one project, dissolved TCE levels were reduced between 72 and 99% in as little as 21 days. In another, from a maximum of 8,600 parts per billion to non-detect in 6 days (regulatory limits on TCE are usually 5 ppb). Because it is an oxidizer, potassium permanganate can be dangerous to handle. But its stability, compared to ozone and hydrogen peroxide, is again an asset, allowing less-concentrated, and therefore less-reactive, solutions to be used in the field.

EXPERIENCE
The Payne Firm has field-tested KMnO4 on free-product TCE and PCE. Dissolved concentrations declined from 51 mg/L to less than 1 mg/L in one day (98% reduction). Since this success, we have proposed use of potassium permanganate at three other sites contaminated with chlorinated solvents. Potassium permanganate is not a silver bullet, but it is a useful new weapon in the remedial arsenal. Please contact Jerry Lisiecki, Don Fay, or Dan Weed at 513-489-2255 or toll free at 800-229-1443 or through e-mail at jbl@paynefirm.com, daf@paynefirm.com or ddw@paynefirm.com to discuss this exciting new technology and how it can be used to reduce the total cost of your next remedial project or the operating cost of existing systems.