This study concerns the treatment of retort water from a modified in-situ shale retort. The water contains organic and inorganic contamination. An oil water separator was designed but tests were not made and are recommended. A steam stripper for ammonia was designed. A thorough experimental investigation of biological oxidation was made. Experiments were made on air and oxygen activated sludge with and without the addition of powdered activated carbon, on a rotating biological contactor and on sequenced equipment. The BOD (initially 4000 mg/1) could be 90% removed from undiluted wastewater preferably using oxygen activated sludge. COD (initially 10,000 mg/1) was not removed in excess of BOD unless carbon was used. The sequence RBC-PAC-AS removed 85% of the BOD and 66% of the COD but is expensive. Solvent extraction and resin adsorption proved unsatisfactory as follow-on treatments to biological treatment. Activated carbon is satisfactory but expensive. Reverse osmosis proved an excellent alternative to biological oxidation and a separate study, not reported here, was made. Tests on the alternative of raising dirty steam from untreated retort matter were strongly recommended.