Soil and Groundwater Contamination Survey and Countermeasure Technologies

Category of Tchnology	Treatment	In Situ Remediation Technology
Media	Soil, Groundwater
Contaminants	Heavy Metal (Cd, Pb, As, Hg, Se, etc) Reducible Inorganic Compounds (Cr6+, etc) Volatile Chlorinated Organic Compounds (TCE, PCE, etc)
	Applied (Demonstrated) Substances	Trichloroethylene
Scope	Concentration Range	Trichloroethylene 20 mg/l or less
	Hydrogeological Conditions	Saturated	Permeable Layer
	Chemical Soil Properties
	Other Remarks	Researches are more advanced in Europe & USA
Technology Description	Classification
	Status	Under Demonstration
	Outline of Technology	Piles mixed with iron powder are driven underground in columns to filter contaminated groundwater for remediation using reduction by iron.  Volatile chlorinated organic compounds will be decomposed by reduction, and heavy metals will be reductively fixed.By adding the reducing agent, sodium sulfite, the rate of reduction increased.
	Required Pre- and Post-treatment
	Enhance Effectiveness through Combination	Decomposition effect will increase if pumping is carried out along with this system.
	Case History	20 mg/l of trichloroethylene was decomposed in a solution sequencing reaction.In a column experiment, 1 mg/l of trichloroethylene was almost completely decomposed under the condition that iron powder was mixed at 20% of weight percent of silica sand with the retention time of 24 hours.  In a model experiment, 1 mg/l of trichloroethylene was almost completely decomposed from a 10 cm layer consisting of iron powder and silica sand at the ratio of 2 : 8.
	Application Examples
	Limitations
	Properties of Treated Soil	Properties are Generally Retained
Schematic Flow Process	Schematic Representation Groundwater Remediation System using Reactive Barrier
Applicability	In Situ Applicability	Possible
	Ground Structures	Applicable even if Ground Structures are Present
	Required Excavation	Reaction barrier needs to be built underground.
	Groundwater Extraction	Pumping will enhance remediation effect.
	Required Space
	Operational Time
	Installation Time
	Maintenance and Control Requirements	Reactive barrier needs to be exchanged as the reaction slows down.  It should be prevented from being clogged.
	Additional Remarks
Secondary Impacts to Environment	Secondary Treatment Required?
	Effects on Living Environment
	Additives
	Possibility of Contaminant Spreading
	Secondary By-products	Hydrogen gas, methane, ethane, ethylene, and a small amount of acetylene were composed from trichloroethylene.

• 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