Installation Date:
1999

Contaminants:
Benzene, Chlorobenzene, 1,2-Dichlorobenzene, 1,4-Dichlorobenzene, Trichloroethene, cis-1,2-Dichloroethene, trans-1,2-Dichloroethene

Reactive Media:
Hydrogen-activation Systems with and without Paladium Catalyst

Construction:
Vertical Wells Shafts and Horizontal Wells.

Point of Contact:
Dr. Holger Weiss
UFZ-Umweltforschungszentrum
Tel: +49 341-235-2060
Fax: +49 341-235-2126
Email: weiss@
pro.ufz.de
Leipzig-Halle GMBH
Permoserstr. 15
04318 Leipzig Germany

Dr. Peter Merkel
University of Tübingen
Tel: +49 7071 297 5041
Fax: +49 7071 5059
Email: peter.merkel@
uni-tuebingen.de
Chair of Applied Geology
Center of Applied Geosciences
Sigwartstr. 10
72076 Tübingen Germany

For more than 100 years, open pit lignite mining activities and the related chemical industries have had a serious impact on soil and ground-water quality in the Bitterfeld Region of Germany. Ground water in the region has been contaminated over an area of about 10 mi². The SAFIRA test site in Bitterfeld was selected as a model location for the demonstration of different types of cleanup technologies under real-world conditions of an in situ pilot plant. A pilot test using reactive columns at the pilot plant was conducted to treat ground water contaminated with benzene (C₆H₆), chlorobenzene (MCB), 1,2-dichlorobenzene (o-DCB), 1,4-dichlorobenzene (p-DCB), trichloroethylene (TCE), cis-1,2-dichloroethylene (DCE), and trans-1,2-DCE. High levels of sulfate (up to 1,000 mg/L) and chloride (up to 1,300 mg/L) are also present.

The goal of the demonstration is the development and implementation of innovative low-energy or passive water treatment technologies for mixed organic contaminants for full-scale in situ application. The SAFIRA test site is underlain by an upper and lower aquifer separated by a 26-ft thick lignite seam. The upper aquifer extends approximately 65 ft below ground surface (bgs) and is comprised of Quaternary glacio-fluvial sand and gravel with intercalated silt. The lower aquifer is about 91 ft-164 ft bgs and is comprised of Tertiary sands. The water table in the area averages 20 ft bgs.

Five 10-ft-diameter vertical well shafts were drilled perpendicular to ground-water flow to a depth of 75 ft bgs. The distance between the well shafts is approximately 62 ft. Ground water is collected from each shaft by two 33-ft-long horizontal wells drilled at an angle of 60°. The pilot plant houses 20 reactors that range in length from 3 ft - 20 ft, depending on the technology it uses. The reactors are designed for a permanent system pressure of 3 bars (2.96 atm) and are operated in a flow-through mode from bottom to top. Flow rates can be varied up to 106 gal/hr.

The combined cost for the installation and design of the pilot system was 11 million Deutsche Marks. Some problems were encountered during the pilot test. Anaerobic degradation of the chlorobenzene could not be shown in the reactors. In addition, sulfate reduction was found to cause catalyst poisoning.

Based on promising results of the pilot test and laboratory experiments, several physical/chemical methods were selected to be tested in a large-scale in situ application, including zeolite-supported palladium catalysis. The pilot project will conclude in June 2002. It is expected that the SAFIRA test site will receive additional public funding over the next few years.

Lessons Learned

One lesson learned from the pilot thus far is that it is likely the complex mixture of contaminants in the ground water at Bitterfeld will require a combination of treatment technologies.

SITE-SPECIFIC REFERENCES

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