Abstract Hydrocarbon production generates aqueous effluents that may contain traces of either hydrocarbon or chemical products which have to be eliminated according to regulations and to the operator's policy, to reduce the potential impact of their discharge on the environment. Quantity of water produced with crude oil increases as fields are getting older. Watery effluents have to be treated by specially designed installations to comply with both regulations and technical requirements. The disposal of the aqueous effluents may be done by various means: dedicated water disposal wells, injection wells (as part of a re-injection system for pressure maintenance), disposal in the water column, at sea for offshore sites or disposal to an onshore water system (lakes, rivers, etc) for onshore sites. The paper will present the approach taken by TOTAL to significantly reduce the quantity of hydrocarbons discharged in surface from produced waters from its existing installations (both onshore and offshore) already equipped with treatment facilities to cope with more stringent performance standards, at best cost. It will describe the methodology and the main techniques used, and present the results obtained in several different cases such as: debottlenecking, lack of efficiency of existing equipment, stabilized emulsion, onshore-offshore sites, and so on.