Title: Passive ventilation to remove PCE from the unsaturated zone – appendix 
Resource Type: document --> technical publication --> report 
Country: Denmark 
Language(s): Danish
Year: 2003 
Availability: Environmental project, Miljørapport nr.806 
Author 1/Producer: Christensen, A.G. 
Other Authors/Producers: Nielsen, H.H.; Fischer, E.V. 
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: ISBN 87-7972-612-7 
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) 7903 
EUGRIS Keyword(s): Contaminated land-->Remediation options-->In situ treatment technologies
Short description: This appendix to the report 805 documents that passive ventilation remediation technique (PV) has been tested at 4 former dry-cleaning establishments polluted with PCE. At all 4 localities, extensive and wide spread contamination in the soil air had developed due to PCE pollution in a sandy and highly permeable unsaturated zone confined under a cover layer of clay. 
Long description: This appendix to the report 805 documents that PV uses the natural pressure gradients between the atmosphere and ventilation wells in the unsaturated zone to strip soil gas. The method can be used to reduce volatile components, i.e. PCE, and other chlorinated compounds, volatile petroleum fractions, MTBE and methane. The vertical pressure gradient depends on the thickness and permeability of the confining overlying soil. The theory and controlling mathematical equations as well as relevant physical parameters behind the PV technique are described in this report. It is further shown step by step how these parameters can be estimated from pilot tests. Furthermore, it is shown how the average airflow from a passive ventilating well can be calculated from a historical time series of atmospheric pressure and physical parameters from pilot tests. The PV system consisting of ventilations wells, a GAC-unit (Granular Activated Carbon) and a one-way valve allowing only discharge of soil gas from the well. The pressure loss through the total system is very low (< 0.5 mBar). The average airflow over a year 0.2 – 1.1 m³/h and the number of discharge periods is approximately 180/year, with an average duration of 13-25 hours. The maximum differential pressure measured was approx. +/- 11 mBar 
Submitted By: Dr Jacqueline Falkenberg WhoDoesWhat?      Last update: 02/04/2007

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