Toshihiko Matsuto

Associate Professor, Hokkaido University Graduate School of Engineering
(Kita 13 Nishi 8, Kita-ku, Sapporo 060 Japan)

Abstract

High chlorine concentrations in leachate is commonly observed in municipal landfill, in which incineration residue occupies an increasing percentage of landfilled material. This paper examines the cause of high salt concentrations through a literature survey focused on the analysis of waste characteristics, incineration ash analysis, and leaching tests of incineration residues etc. The main findings are: Incineration-oriented strategies are the principal cause of the problem, while the increase of plastic components proved to be minor contributing factor. Through the incineration process, waste is turned into an inorganic material which is soluble in the leachate. The leachate strength also depands on landfill operation process. Diverting untreated fly ash from the landfill will decrease chlorine concentrations to 1/3, but decrease calcium concentrations only to 2/3.

Key words: high salt concentration, leachate, incineration residue, plastics