If anything, I imagine the geothermal system could act to destroy otherwise hard to remove organics, like drug residues. Various dissolved metals and metal-ric

If anything, I imagine the geothermal system could act to destroy otherwise hard to remove organics, like drug residues. Various dissolved metals and metal-rich surfaces could act as catalysts. Some geothermal systems in the Salton Sea have had issues with deposition of metal sulfides, with the deposits being so rich in silver they are in effect high grade ores (including native silver metal). Unfortunately these weren't economical to extract, but they do act as artificial replicas of natural ore forming systems.