A process for the production of highly purified water from Fischer-Tropsch reaction water, which process includes at least the steps of a primary treatment stage comprising biological treatment for removing at least a fraction of dissolved organic carbon from the Fischer-Tropsch reaction water to produce a primary water-enriched stream, a secondary treatment stage comprising solid-liquid separation for removing at least some solids from at least a portion of the primary water-enriched stream to produce a secondary water-enriched stream, and a tertiary treatment stage comprising a dissolved salt and organic removal step for removing at least some dissolved salts and organic constituents from at least a portion of the secondary water-enriched stream.