Masakatsu Hiraoka* and Shin-ichi Sakai**

*Professor, Faculty of Engineering, Kyoto University
** Instructor, Environment Preservation Center, Kyoto University

+ Correspondence should be addressed to Shin-ichi Sakai:
Environment Preservation Center, Kyoto University
(Yoshida Honmachi, Sakyo-ku, Kyoto 606-01 Japan)

Abstract

Fly ash from municipal waste incineration (MWI) is regulated under the hazardous waste regulation called "Waste under Special Control" , according to the Amendment of the Waste Disposal and Public Cleansing Law of 1991 in Japan. The properties and treatment methods of fly ash from MWI are introduced and waste cycling strategies in the future including MWI fly ash control are discussed. Fly ash from MWI contains more heavy metals (lead, cadmium, zinc), sodium chloride and potassium chloride than bottom ash from MWI. The levels of chlorinated dioxin compounds are 0.1-100ng-TEQ/g. The ideal treatment strategies should have the priorities of (1)Resource Recycling, (2)Solidification/Stabilization and (3)Storage/Control. The methods of Resource Recycling consist of acid extraction and/or high temperature melting, which result in the concentration and recycling of heavy metals. Solidification/Stabilization and Storage/Control are important short-term measures.

Key words: municipal waste incineration, fly ash, treatment, recycle