Sota Nakagawa*, Toshihiro Tanaka**, Saburo Ito*** and Yousei Katsu**

* Water Science Lab., Center for Advanced Technology, EBARA Research Co., LTD,
** Environmental R&D Dept., Environmental Technology Development Center, EBARA Corporation
*** Envir. System & Equip. Division, EBARA Corporation

+ Correspondence should be addressed to Sota Nakagawa:
(4-2-1 Honfujisawa, Fujisawa city 251-8502 Japan)

Abstract

Two types of advanced oxidation processes, O3/H2O2 and UV/O3/H2O2 processes, were tested to evaluate their performances of decomposing dioxins contained in a landfill leachate. In this experiment, the concentration of total dioxins reduced from 6,500pg/l of the raw water to 3,500pg/l and 1,900pg/l of the treated waters by the O3/H2O2 and UV/O3/H2O2 processes, respectively. Comparing the decomposition data profiles of each dioxin homologue, both methods showed nearly the same performance for low-chlorinated compounds. But for high-chlorinated compounds, the UV/O3/H2O2 process showed a better decomposition performance than the O3/H2O2 process. Ninety one percent of total TEQ of the raw water was composed of tetra, penta and hexa-chlorinated compounds and the TEQ deriving from high-chlorinated compounds was small. From our data, the UV/O3/H2O2 process was more useful for the removal of total dioxins, but the O3/H2O2 process was showed to be useful for reducing TEQ which expresses the actual toxicity of dioxins.

Key words: landfill leachate, dioxins, advanced oxidation processes