Immobilization of chromium-contaminated soil by means of microwave energy

To reduce the amount of hazardous wastes contaminated by heavy metals, a ne w technology to immobilize heavy metal ions is desired. Microwave (MW) tech nology which can be used to vitrify the contaminated soil wastes and immobi lize the heavy metal ions for this purpose to satisfy the leachate test sta ndard. We found that 90% + of the chromium-contaminated soil went through t he glass/ceramic transformation and was thus vitrified after being radiated with MW for 60 min. The chromium ion (Cr6+) concentration in the leaching test of all the vitrified soil samples is less than 1 mg/l, below the USEPA regulatory limit of 5.0 mg/l. This technology may become a major treatment method for hazardous wastes if the large-scale field test proves to be suc cessful. In this paper, we will present the experimental conditions, the re sults and the future projects. (C) 1999 Elsevier Science B.V. All rights re served.