Environmental Impact Evaluation of Heavy Metals Contained in the Fly and Bottom Ash

Kentaro Aoi*, Yoshiro Ono**, Kenji Namiki*** and Aya Yamada**
* Department of Environmental & Civil Engineering, University of Okayama[Present, Suido Kiko Kaisha, Ltd.]
** The Graduate School of Natural Science and Technology, University of Okayama
*** Seiko Instruments Inc.
+ Correspondence should be addressed to Yoshiro Ono:
(3-1-1 Tsushima-naka, Okayama-city 700-8530 Japan)

Abstract
Characteristics of leaching of heavy metals from fly and bottom ash were investigated experimentally. Leaching activity was found to depend on pH, L/S ratio and ion concentration in the leaching solution. Low pH increased the elution of lead and cadmium. In order to evaluate the short- and long-term elution of landfill sites, various leaching tests are required. These include the serial batch test and/or the availability test for pH and L/S ratio. The impact analysis of heavy metals on the environment was tested using a the method which combines the results from several leaching tests and hazardous scoring techniques. As a result, it is obvious that short-term landfill cadmium and long-term lead have a more hazardous impact.

Key words: fly and bottom ash, leaching test, heavy metals, hazardousness scoring system