Research Contents : Technology for water treatment
·Microorganism control technology
·Diamond electrodes
·Heavy metal-recovery from contaminated soil
Heavy metal-recovery from contaminated soil
 
  Conventionally, heavy metal-contaminated sites are treated by Off site-dumping (Fig.1 [1]), having disadvantages of busy adit of dump trucks, of potential second-contamination. Soil washing approach (Fig.1 [2]) has been proposed to sift out coarse grained soil to be filled back, but the fine grained soil (silt) still have to be brought out to the dumping yard. We have developed a heavy metal material recovery process accepting the contaminated silt and treat it in an electrolysis reduction reactor(Fig.1 [3]) .
 
Fig.1 Remediation methods for heavy-metal contaminated site
Fig.1  Remediation methods for heavy-metal contaminated site
 
  In the Electrolysis Reduction Process, heavy metals in sparingly soluble forms can be extracted from the silt efficiently, under reductive potential in a cathode section, which is insulated from anodic oxides by an ion exchange membrane (Fig.2).

  The Electrolysis Reduction Process is being applied to the full-scale site remediation by EBARA, as the unprecedented technique capable of cleaning up the heavy metal-contaminated silt and of recovering the metal material.
 
Fig.2 Schematic diagram of the Electrolysis Reduction Process
Fig.2 Schematic diagram of the Electrolysis Reduction Process (Lead contaminated soil)
 
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