Soil and Groundwater Contamination Survey and Countermeasure Technologies

Category of Tchnology	Treatment	Treatment Technology
Media	Soil
Contaminants	Oil (Non Volatile Hydrocarbons)
	Applied (Demonstrated) Substances	Oil
Scope	Concentration Range
	Hydrogeological Conditions	-	-
	Chemical Soil Properties	When soil is easy to melt, it is not possible to raise the combustion temperature.
	Other Remarks
Technology Description	Classification	Decomposition
	Status	Fully Commercialized Soil and Groundwater Countermeasure Test Study (Performed 1997)
	Outline of Technology	The oil-contaminated soil is charged into a rotary kiln and heated; the oil components are removed by pyrolysis or volatilization.  The breakdown products formed by pyrolysis of the oil components and the volatilized components from the soil are recombusted in a secondary combustion furnace for breakdown to reduce them to harmless substances.  The particular feature of this technology is that the combustion temperature is controlled with a view to permit the reuse of the soil after treatment.
	Required Pre- and Post-treatment	In the event that harmful substances that cannot be broken down and detoxified by secondary combustion, it will be necessary to treat the exhaust gases in the appropriate manner.
	Enhance Effectiveness through Combination
	Case History	Heat treatment was applied at three temperature, namely, 550, 800, and 950°C, to a contaminated test soil prepared by adding actual contaminated soil and oil.  Ignition loss at red heat temperatures of 800°C or above was 0.4%. No hexane-extractable substances were detected.  The mutagenicity variability tests was also negative.  Dioxins and some polycyclic aromatic hydrocarbons believed to have been formed in the heat treatment process were observed in the secondary combustion exhaust gases.  This suggests that some appropriate exhaust gas treatment method will be necessary.
	Application Examples
	Limitations	When the oil content is low, auxiliary fuel is required in large amounts.
	Properties of Treated Soil	Possibility of Change in Properties
Schematic Flow Process	Oil Contaminated Soil Thermal -Treatment System - Overall Flowsheet
Applicability	In Situ Applicability	Not Possible
	Ground Structures	-
	Required Excavation	Total excavation (Applied to excavated contaminated soil)
	Groundwater Extraction
	Required Space	-
	Operational Time	If contaminated soil is excavated properly, soil cleaning will be completed with the excavation stage.
	Installation Time
	Maintenance and Control Requirements	The combustion temperature needs to be controlled by controlling the contaminated soil, auxiliary fuel and air supply rates, respectively.
	Additional Remarks
Secondary Impacts to Environment	Secondary Treatment Required?	Off-gas Treatment Waste Treatment
	Effects on Living Environment	Noise
	Additives
	Possibility of Contaminant Spreading	Provided that the exhaust gases are treated properly there will be no risk of the contamination’s spreading.
	Secondary By-products	Dioxins and some polycyclic aromatic hydrocarbons have been detected in the secondary combustion exhaust gases.  These compounds have not been detected in the soil itself and are therefore believed to have formed in the treatment process.

• 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