Ken Kanaya* and Yutaka Terashima**

*Department of Environmental and Sanitary Engineering, Faculty of Engineering, Instructor Kyoto University
**Department of Environmental and Sanitary Engineering, Faculty of Engineering, Professor Kyoto University

+ Correspondence should be addressed to Ken Kanaya:
(Yoshida Honmachi, Sakyo-ku, Kyoto 606-01 Japan)

Abstract

The quantity and quality changes of the leachate from a bed packed with incinerated ash from municipal solid waste were investigated under real meteorological conditions for one year. A tank model taking into account the actual precipitation and leaching phenomenon in the packed bed, was constructed and used for evaluating the fluctuations of both water quantity and quality. Main conclusions obtained in this investigation were as follows:(1)Neither the monthly mean ratio of leachate quantity to precipitation ( = monthly leaching coefficient) nor the monthly mean ratio of evaporation from the packed bed surface to evaporation from water surface ( = monthly specific evaporation) were constant during the course of the experiment. These were fluctuated with a change in meteorological conditions. (2)The change of Cl- concentration in the leachate could be explained by the water quantity tank model and the water quality tank model based on two-step leaching of Cl in the ash. In the two-step water quality tank model, it was assumed that the easily leachable Cl in the ash first leached, and then the non-easily leachable Cl (total Cl content-easily leachable Cl) leached at a slower rate. (3)Under real meteorological conditions, even in a bed packed only with incinerated ash from municipal solid waste, it was likely that the COD and TN contents in the ash were partially biodegraded. The contributions of the biodegradation were small compared to the original total contents, but large compared to the amounts in the leachate.

Key words: municipal solid waste, incinerated ash, leachate, real meteorological condition, tank model