Title: Thermal assisted vacuum extraction of perchlororethylene. Main report 
Resource Type: document --> technical publication --> report 
Country: Denmark 
Year: 2003 
Availability: Environmental project, Miljørapport nr. 823 
Author 1/Producer: Jørgensen, T.H. 
Other Authors/Producers: Jepsen, J.D.; Nissen, L.; Skou, H. and Gudbjerg, J. 
Author / Producer Type: Agency, regulator or other governmental or inter-governmental body 
Publisher: The Danish Environmental Protection Agency, Miljøstyrelsen 
Publisher City: Strandgade 29, DK-1405 Copenhagen K, Denmark 
ISBN: 87-7972-751-4 
Report / download web link (=direct link): http://www2.mst.dk/common/Udgivramme/Frame.asp?pg=http://www ...  
Format (e.g. PDF): PDF 
Size: (e.g. 20mb) 114 
EUGRIS Keyword(s): Contaminated land-->Remediation options-->In situ treatment technologies
 
Short description: Soil and groundwater contamination with tetrachloroethylene (PCE) produced a soil air contamination covering more 10,000 m³ and affected the indoor climate in hundreds of apartments. The unsaturated zone was cleaned by vacuum extraction, supplemented by steam injection, while groundwater cleanup was by chemical oxidation by injection of potassium permanganate. 
Long description: In order to achieve a rapid release of PCE, vacuum extraction was supplemented by heating of the soil by steam injection. As the contamination source was only 1-2 m below the existing houses, heat was applied below the source. Concerns concerning uncontrolled spreading of contamination and of steam as well as the risk of subsidence were addressed in the design phase. An area of approx. 400 m² was affected by the steam injection; and 300 m² was heated to temperatures exceeding 90°C. The steam front spread mainly horizontally and heating was greatest from the groundwater table in 6.5-7 m´s depth to 4 m below ground level. Heating above 3.5 m depth occurred by heat conduction and the critical temperature was estimated to be 50°C in 1.5 m´s depth. Air was added to the injected steam in order to minimise possible condensation of PCE. A number of difficulties arose in connection with cooling, noise levels, clogging, steam generator and poor capacity of the horizontal vacuum extraction filters. However cleanup of the source areas was completed 3 months ahead of schedule and after 1 year's operation the soil air concentrations in the source area were reduced from 66,000 mg/m³ to below 5 mg/m³. 
Submitted By: Dr Jacqueline Falkenberg WhoDoesWhat?      Last update: 02/04/2007