Study on Oxidation-Reduction Condition of the Leachate of Fly Ash from Thermal Treatment

Abstract

Some heavy metals in the leachate of municipal solid waste can change their toxicity because of redox reactions, so it is important to comprehend the oxidation-reduction conduction of the leachate. We can see them by measuring the pH and Eh of the leachate. Eh is the electrode potential based on hydrogen and calculated by converting ORP. but there are considerable variations of Eh for each measurement. Therefore, we evaluated whether we can use Eh as an indicator of oxidation-reduction state. The value of Eh was corrected to account for the effect of variability in pH measurements. At first, the variation value of corrected Eh was 70 mV maximum. However, by improving the methods of experiments to control the oxidation, the variation value of the three measurements was less than 20 mV. Then, we can use Eh as the indicator of the oxidation-reduction condition of the leachate.