Kentaro Miyawaki*, Nobutoshi Tanaka* and Toshihiko Matsuto*

*Department of Environmental and Sanitary Engineering, Faculty of Engineering, Hokkaido University

+ Correspondence should be addressed to Nobutoshi Tanaka:
(Kita 13 Nishi 8, Kita-ku, Sapporo 060 Japan)

Abstract

In Japan more than 70% of municipal solid waste (MSW) has been incinerated. Since the heavy metal content is high in incinerator ash, there is a potential hazard of releasing heavy metals to the environment. In this paper, we did experimental studies on biological sulfate reduction in leachate from ash to know the possibility of heavy metal insolubilization.

In this experiment, the influence of environmental conditions on the activity sulfate-reducing bacteria (SRB) was almost the same as reported by other researchers. Once those conditions were met, sulfide was produced by SRB in leachate from ash. Sulfate reduction was stopped even though sulfate and TOC still remain in leachate, because SRB in the authors' experiment utilized mainly lactate. Only 25% of TOC was transformed into lactate.

Key words: sulfate-reducing bacteria, MSW incinerator ash, insolubilization of heavy metal, Leachate