KONATES – Design and pilot plant operation for the use of contaminated aquifers for energy management with ATES plants

A pilot plant for an aquifer thermal energy storage (ATES) system in a contaminated aquifer is under construction at the scientific park of Leipzig. The research at this pilot plant is focused on developing and testing technologies to simultaneously store energy from shallow aquifers through an ATES system and remediate the contaminated aquifer.

For this purpose, investigations will be conducted in an approximately 10-meter-deep sandy/gravelly aquifer which is contaminated with chlorinated volatile organic compounds (Cl-VOCs). The main contaminants are trichloroethene (TCE, up to 6.0 mg/l) and cis-dichloroethene (cis-DCE, up to 0.4 mg/l).

With a two-well system that runs cyclically, the proposed ATES system will inject up to 80 °C heated water. This has a greater impact on the chemical composition of the groundwater than ATES systems that operate at lower temperatures. A previous field project revealed a considerable change in hydrogeochemistry and the microbiological community at temperatures of 45 °C and 60 °C.

As a result, this study investigates the hydrochemical and biological interactions that occur in the extraction and injection wells, the thermally affected aquifer as well as in the aboveground system. Cl-VOCs will be removed from groundwater using an on-site regenerable zeolite absorber (Fe-zeolite) and in situ degradation with persulphate.

Furthermore, these investigations will be supported by stable isotope biochemical and abiotic migration investigations of Cl-VOCs as well as microbiological and geochemical analyses including trace elements. It is anticipated to enhance the carbon footprint of urban energy management by the ATES operation, including groundwater remediation.