Patent ID: 7150831

Claim:
A process for the production of purified water from Fischer-Tropsch reaction water containing oxygenated hydrocarbons, aliphatic, aromatic and cyclic hydrocarbons and inorganic compounds, wherein the purified water is an aqueous stream having a COD of between 20 and 500 mg/l, a pH of between 6.0 and 9.0, a suspended solids content of less than 250 mg/l and a total dissolved solids content of less than 600 mg/l, and wherein the process includes at least the steps of: a) a primary treatment stage comprising distillation for removing at least a fraction of non-acid oxygenated hydrocarbons from the Fischer-Tropsch reaction water to produce a primary water enriched stream; b) a secondary treatment stage comprising liquid-liquid extraction for removing at least a fraction of organic acids from at least a portion of the primary water enriched stream to produce a secondary water enriched stream; c) a tertiary treatment stage comprising biological treatment for removing at least a fraction of acidic oxygenated hydrocarbons from at least a portion of the secondary water enriched stream to produce a tertiary water enriched stream; and d) a quartic treatment stage comprising solid-liquid separation for removing at least some solids from at least a portion of the tertiary water enriched stream.