By 2028, the share of geothermal energy in the energy mix will double. To achieve this ambitious objective, the major problem of geothermal fluids circulation in aquifers has to be overcome in order to gain in plant efficiency. The microorganisms, evolving in these porous media, form biofilms that grow and clog the pores leading to a reduction in the production rate. To solve this issue, biocides are injected but are not very efficient. The BIOCIDES project proposes an experimental approach covering a broad spectrum of space and time scales to enrich the fundamental knowledge of bio-clogging mechanisms and their remediation in porous media. These tools, coming from fundamental sciences and mastered by the partners of our consortium will be used to determine innovative indicators assessing the effectiveness of biocide-based treatments in porous media and thus achieving their reasoned use.