| Title | Biogeochemical Characterisation of Geothermally Used Groundwater in Germany |
|---|---|
| Authors | Alexandra Vetter, Andrea Vieth, Kai Mangelsdorf, Stephanie Lerm, Mashal Alawi, Markus Wolfgramm, Andrea Seibt, Hilke Würdemann |
| Year | 2010 |
| Conference | World Geothermal Congress |
| Keywords | geothermal plant, energy storage, microbiology, geochemistry, biomarker, DOC |
| Abstract | The multidisciplinary research project “AquiScreen” investigates the working reliability of geothermal utilization of aquifers, especially, considering microbial activity as well as particle transport and relocation. Major interest is the impact of microbial populations on aquifer systems. Therefore, the project integrates microbiological, biogeochemical, mineralogical, and petrologic investigations to qualify and quantify the variability of subsurface microbial communities in the fluid and solid phases of shallow and deep geothermal systems in Germany. Organic compounds as well as sulfate (as an electron acceptor) are monitored to assess the operational state of geothermal plants and energy storages with respect to the working reliability. Our study shows, that the investigated parameters (such as low molecular weight organic acids –LMWOA - and sulfate) can be indicative markers for the evaluation of these plants. Sulfate concentration in shallow geothermally used aquifer systems (energy storages) seems to be suited to estimate microbial impact in plants. For deep energy storages, variations in LMWOA and DOC (dissolved organic carbon) concentration is suggested to be a marker for changes in fluid chemistry and can be an initial indication of fermentative microbial colonization. In the investigated geothermal plants and energy storages, sufficient amounts of electron acceptors and -donors are detected and are available as a potential feedstock for microbial life. Furthermore, we detect in all investigated geothermally used plant systems in the North German Basin microbial communities by 16S rDNA profiles and biomarker analyses (phospholipids). In some cases the bacterial metabolism may result in scale formation, filter clogging and corrosion processes. |