Soil and Groundwater Contamination Survey and Countermeasure Technologies

Category of Tchnology	Treatment	Treatment of Excavated Soil
Media	Soil
Contaminants	Heavy Metal (Cd, Pb, As, Hg, Se, etc) Oil (Non Volatile Hydrocarbons)
	Applied (Demonstrated) Substances	As, Pb
Scope	Concentration Range	Applicable for wide range of the concentration.  More than 1 % is desirable.
	Hydrogeological Conditions	-	-
	Chemical Soil Properties
	Other Remarks	Chemical property of contaminant is important to determine appropriate reagent.
Technology Description	Classification	Separation
	Status	Under Demonstration Soil and Groundwater Countermeasure Test Study (Performed 1997)
	Outline of Technology	Flotation is one of the technology to separate minerals from ore.  Contaminated soil is pulped and aerated.  Hydrophobic particles are floated by bubble to separate from hydrophilic particles.  Contaminant is concentrated in floated fraction.  Contaminant is desirably concentrated through soil washing before flotation.
	Required Pre- and Post-treatment	Floated particles which contains high concentration of contaminant is treated as waste or raw material.
	Enhance Effectiveness through Combination
	Case History	Contaminated soil with Pb (more than content reference value) ant As (more than soil environmental quality standard) is treated with flotation after magnetic and gravity separation.  Sulfuret reagent is selected among flotation reagent after chemical property of the Pb is analyzed by X-ray diffraction.  Pb and As are 10 times concentrated in floated fraction.  Though Pb and As concentration of precipitated fraction reduced 20 to 40 %, content of Pb didn’t meet reference value.
	Application Examples	Oil contaminated soil is also tested.
	Limitations	Flotation reagent is selected in treatability test.
	Properties of Treated Soil	Properties are Generally Retained
Schematic Flow Process
Applicability	In Situ Applicability	Not Possible
	Ground Structures	-
	Required Excavation
	Groundwater Extraction
	Required Space	-
	Operational Time
	Installation Time
	Maintenance and Control Requirements
	Additional Remarks
Secondary Impacts to Environment	Secondary Treatment Required?	Effluent Water Treatment
	Effects on Living Environment	Noise
	Additives	Others (Flotation reagent)
	Possibility of Contaminant Spreading	None
	Secondary By-products	None

• 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