Akiko Kida* and Yukio Noma*

* Hiroshima Prefectural Health and Environment Center

+ Correspondence should be addressed to Akiko Kida:
(1-6-29 Minami-machi, Minami-ku, Hiroshima 734 Japan)

Abstract

Major components (sodium, potassium, calcium, chlorine and sulfur) in waste incinerator ash were investigated in regards to their average contents and their leachabilities. A liquid/solid (L/S) ratio of 200 in batch leaching tests is recommended to obtain a totally soluble amount for these components, especially calcium. The results of column tests showed that sodium, potassium and chloride ion leached first, followed by calcium and sulfate ion, and then finally calcium. Estimated concentrations of components in a hypothetical leachate for a L/S=1 condition, using the release amounts from the column test are almost the same as some actual cases. In some cases, a high salt leachate (more than 1%) can be seen ten years after disposal has been completed. Sodium and chloride ions are effective indicators for estimating first stage leaching from MSW ash. It should be noted that calcium and sulfate ions will leach more than ten times longer than Na, K, Cl.

Key words: salt component, leaching test, column test, liquid/solid ratio, calcium