Hirofumi Sakanakura*, Kazutoshi Kanno**, Takayuki Matsuo*, Toshihiko Matsuto* and Nobutoshi Tanaka*

* Division of Environmental and Resource Eng., Graduate School of Eng., Hokkaido Univ.
** Kajima Corporation, Ltd.

+ Correspondence should be addressed to Nobutoshi Tanaka:
(Kita 13, Nishi 8, Kita-ku, Sapporo 060-8628 Japan)

Abstract

Chemical treatment with chelating agents is a method of stabilizing heavy metals in Air Pollution Control residue (APC residue) from Municipal Solid Waste (MSW) Incinerators. The aim of this research was to find the appropriate ratio of chelating agent and APC residue to achieve the optimal stabilization of heavy metals. The investigations focused on Pb as a representative and relevant heavy metal in APC residue. APC residue samples were collected from three MSW incinerators. The samples were mixed with chelating agent and/or pH controlling agent at different ratios. In some conditions Pb, Cu or Zn metal salt were added to determine their influence on Pb release. Then they were inspected according to the Japanese Leaching Test, stated in The Japanese Environmental Agency Notification No.13 (JLT13) . The experiments proved that the sum of the content of Pb and Cu is the deciding factor for the amount of chelating agent that is needed to meet the disposal standard for Pb (0.3 mg/L) . Another important outcome is that it is possible to control the release of Pb by adding pH-controlling agents. In this case, the disposal standard for Pb was met for leachate that was adjusted to a pH of 9 to 10.

Key words: air pollution control residue, chemical agent treatment, chelating agent, heavy metals, leaching test