be developed for the cathode and oxidation for the anode, and the groundwater
condition cannot be determined simply by the size (or sign) of E h . Real oxidationreduction conditions in the space between the electrodes will depend on a number of
geochemical processes.
4.2.3 Site Application of DC in Hořice
As in the case of the previously described reactor, it is possible to demonstrate the
effect of an electric current directly on groundwater in an in situ arrangement. A pilot
polygon was located at the site of the Karbox plant (Hořice in Podkrkonoší, Czech
Republic). The site, located in a town, was contaminated in the 1970s and 1980s by
chlorinated ethenes, which were released from an industrial activity. The total area of
contamination is approximately 120 m  60 m. Geologically, the site is part of the
Bohemian Cretaceous Basin divided into Cenomanian and lower Turonian layers.
The Quaternary cover is formed by a 6-meter-thick layer of loess and secondary
loess separated from Turonian sediments by about a meter-thick layer of silty clays.
The groups of strata are tectonically afflicted and vertically shifted. The uppermost
and contaminated aquifer is in the 10-m-thick Quaternary sediments mainly
represented by re-deposited sandy silty clays of a very low permeability (transmissivity of 10
À7 m
2 s
À1 ). The contamination was located in five separate hotspots,
which were considerably elongated in the direction of the groundwater flow. A
6 Â 6-meter test polygon was defined around the well IS10.
The site consists of five contaminated spots elongated in the direction of the
groundwater flow. The chlorinated ethenes concentration in groundwater reached
60 mg L
À1 . The experiment run around the well IS-10, which is a hotspot for total
concentration of ClE and contains the highest concentrations of all daughter products
of PCE sequential dechlorination (Fig. 4.7). Only the PCE highest concentration is
Fig. 4.7 Location of the electrodes and monitoring boreholes in the test polygon Hořice
72
M. Černík et al.
condition cannot be determined simply by the size (or sign) of E h . Real oxidationreduction conditions in the space between the electrodes will depend on a number of
geochemical processes.
4.2.3 Site Application of DC in Hořice
As in the case of the previously described reactor, it is possible to demonstrate the
effect of an electric current directly on groundwater in an in situ arrangement. A pilot
polygon was located at the site of the Karbox plant (Hořice in Podkrkonoší, Czech
Republic). The site, located in a town, was contaminated in the 1970s and 1980s by
chlorinated ethenes, which were released from an industrial activity. The total area of
contamination is approximately 120 m  60 m. Geologically, the site is part of the
Bohemian Cretaceous Basin divided into Cenomanian and lower Turonian layers.
The Quaternary cover is formed by a 6-meter-thick layer of loess and secondary
loess separated from Turonian sediments by about a meter-thick layer of silty clays.
The groups of strata are tectonically afflicted and vertically shifted. The uppermost
and contaminated aquifer is in the 10-m-thick Quaternary sediments mainly
represented by re-deposited sandy silty clays of a very low permeability (transmissivity of 10
À7 m
2 s
À1 ). The contamination was located in five separate hotspots,
which were considerably elongated in the direction of the groundwater flow. A
6 Â 6-meter test polygon was defined around the well IS10.
The site consists of five contaminated spots elongated in the direction of the
groundwater flow. The chlorinated ethenes concentration in groundwater reached
60 mg L
À1 . The experiment run around the well IS-10, which is a hotspot for total
concentration of ClE and contains the highest concentrations of all daughter products
of PCE sequential dechlorination (Fig. 4.7). Only the PCE highest concentration is
Fig. 4.7 Location of the electrodes and monitoring boreholes in the test polygon Hořice
72
M. Černík et al.