The escalating demand for metals and dwindling ore grades necessitates more efficient metal production, reducing the strain on natural resources and environmental hazards. Metal recovery via hydrogen sulfide precipitation offers a sustainable solution, enhancing metal recovery efficiency and reducing waste streams, such as tailings. Despite the commercial availability of sulfidogenic systems, their widespread application is hindered by high operational and capital costs (OPEX and CAPEX). Using elemental sulfur (S0) instead of the commonly used sulfate (SO42-) could lower OPEX, as it requires four times less electron donor, a key factor in operational expenses. Further, consolidating the process into a single unit could reduce CAPEX compared to the current compartmentalized procedure, albeit at the risk of exposing microorganisms to harsh conditions. This thesis investigates elemental sulfur reduction using full-scale reactor granular sludges as inoculum under extreme conditions, paving the way for a streamlined single-unit metal recovery process.