Shin Taniguchi*, Akira Miyamura**, Akihiro Ebihara***, Akihiko Murakami* and Masaaki Hosomi*

* Dept. of Chemical Engineering, Tokyo University of Agriculture and Technology
** Environment Control R&D Laboratory, Ebara Research Co., Ltd.
*** Environmental Consulting Center, Ebara Corporation

+ Correspondence should be addressed to Akihiro Ebihara:
(1-6-27 Konan, Minato, Tokyo 108 Japan)

Abstract

Containment has been the conventional method for dealing with PCB-contaminated soil, however, in terms of environmental protection, it is more desirable to desorb PCBs from the soil. We have adapted the Base Catalyzed Decomposition (BCD) process for desorbing PCBs from the soil. Laboratory tests were carried out in an effort to confirm the availability of this process for Japan's environmental standard on PCB-contaminated soil. Tests using this process for treating seven different types of soil all resulted in PCB levels which satisfied Japan's environmental standard for PCB-contaminated soil. There were no PCBs detected (below 0.0005mg/l) in the test fluid leached during leaching tests on the treated soil. Comparison of the PCB content in the soil, before and after treatment by the BCD process, indicated that a PCB removal of 99.79% was achieved. It was also confirmed that charging NaHCO3 was effective for reducing the PCB content in the soil, and that PCBs underwent partial de-chlorination and a degradation reaction. The authors consider the organic materials to be working in the soil as hydrogen donors through those reactions.

Key words: PCBs, poly-chlorinated biphenyl, contaminated soil, remediation