Soil and Groundwater Contamination Survey and Countermeasure Technologies

Category of Tchnology	Treatment	In Situ Extraction Technology
Media	Soil, Groundwater
Contaminants	Heavy Metal (Cd, Pb, As, Hg, Se, etc) Inorganic Compounds (total CN, etc) Reducible Inorganic Compounds (Cr6+, etc) Volatile Chlorinated Organic Compounds (TCE, PCE, etc) Volatile Hydrocarbon (Benzene, etc)
	Applied (Demonstrated) Substances	Hexavalent Chromium
Scope	Concentration Range
	Hydrogeological Conditions	Saturated Unsaturated	Permeable Layer Semi to Impermeable Layer
	Chemical Soil Properties	The care must be taken in dealing with the soil containing a large quantity of chlorine ion.
	Other Remarks
Technology Description	Classification
	Status	Under Demonstration Soil and Groundwater Countermeasure Test Study (Performed 1995)
	Outline of Technology	Using the electromagnetic field generated in the soil layer passing a direct current through the ground, contaminated materials, especially water-soluble heavy metals like hexavalent chrominum are extracted from the soil layer and removed.
	Required Pre- and Post-treatment	It is necessary to treat and collect chromium using such as adsorption.
	Enhance Effectiveness through Combination
	Case History	At former plating facility site contaminated with hexavalent chromium, 50 V DC was passed through the soil layer for about 4 months.  As a consequence of the test, the chromium in the pore water of the soil layer decreased to 5 mg/l from 440 mg/l of the maximum initial concentration.
	Application Examples	None
	Limitations
	Properties of Treated Soil	Properties are Generally Retained
Schematic Flow Process
Applicability	In Situ Applicability	Possible
	Ground Structures	Not Applicable
	Required Excavation	May need the excavation for cut-off wall installation.
	Groundwater Extraction	None
	Required Space
	Operational Time	May need longer time due to slower removal rate.
	Installation Time
	Maintenance and Control Requirements	Water supply, drainage, recover of cromium
	Additional Remarks
Secondary Impacts to Environment	Secondary Treatment Required?	Effluent Water Treatment
	Effects on Living Environment	Others (Stray current)
	Additives
	Possibility of Contaminant Spreading	None
	Secondary By-products	It can be considered theoretically that chlorine gas generates by electrolysis in the case of this treatment applying to the soil containing a large quantity of chlorine ion.

• Understanding the Contamination Survey and Countermeasure Technology Description Sheet
• Where to make contact

Soil Environment Management Division, Water Environment Department, Environmental Management Bureau, Ministry of Environment
Tel: +81-3-5521-8319
E-mail: MOE@env.go.jp