Soil and Groundwater Contamination Survey and Countermeasure Technologies

Category of Tchnology	Treatment	Counterplan Technology
Media	Soil
Contaminants	Semi Volatile Chlorinated Organic Compounds (PCB, etc)
	Applied (Demonstrated) Substances	PCB
Scope	Concentration Range	10-2,500ppm
	Hydrogeological Conditions	-	-
	Chemical Soil Properties	High organic containing soil may cause partial dechlorination in soil reactor.
	Other Remarks
Technology Description	Classification	Decomposition
	Status	Fully Commercialized Soil and Groundwater Countermeasure Test Study (Performed 1993)
	Outline of Technology	There added NaHCO3 to a PCB-contaminated soil, which soil mixture is heated in a soil reactor to 300-350°C to separate the water and the volatile organic compounds in the soil to recover as condensate.  The condensate containing PCB and a high boiling point oil are charged to a liquid phase reactor, further an alkali and a catalyst are added to the reaction mixture.  The mixture is heated to decompose the organic chlorine compounds such as PCB.
	Required Pre- and Post-treatment	As the pre-treatment, granules and stones are removed from the soil, and water content of the soil is adjusted to about 15%.  As for the post-treatment, chlorine is removed because the decomposition of PCB in the liquid phase reactor generates salts.  The liquid product free of chlorine is used as a fuel.
	Enhance Effectiveness through Combination
	Case History	Soil reactor: PCB removal rate from the PCB-contaminated soil was 99.99% or more.  Liquid phase reactor: PCB decomposition rate from the condensate was about 99.999%.
	Application Examples	A treatment demonstration test was carried out using a portable BCD soil reactor dealing with PCB-contaminated soils excavated from the site of electric and electronics parts plant.
	Limitations	After the excavation of contaminated soil, a soil reactor implements extraction and decomposition.  If other contaminants such as heavy metals exist, it is necessary to remove separately the heavy metals or other contaminants.
	Properties of Treated Soil	Possibility of Change in Properties
Schematic Flow Process
Applicability	In Situ Applicability	Possible
	Ground Structures	-
	Required Excavation	Full excavation (Applied to the excavated contaminated soil)
	Groundwater Extraction
	Required Space	Area of about a single trailer truck is required for the demonstration test.
	Operational Time
	Installation Time
	Maintenance and Control Requirements
	Additional Remarks
Secondary Impacts to Environment	Secondary Treatment Required?	Effluent Water Treatment  Off-gas Treatment
	Effects on Living Environment
	Additives	Others (Alkali, Catalyst, High Boiling Point Oil)
	Possibility of Contaminant Spreading	None
	Secondary By-products	Even if dioxins are generated temporarily, they are decomposed in the BCD reaction 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