Industrial effluents have variable compositions depending on the industry: refineries, pharmaceuticals, distilleries, food processing, paper mill… The most widespread treatment of effluents containing organic pollutants is the biological way, but microorganisms are unsuitable in the case of refractory or toxic products. Legislations regulate more and more severely the management of these wastes and favor the development of alternative processes allowing to treat effectively particular pollutions, as in pre-treatment before a biological process or for a complete degradation of organic matters in carbon dioxide and in water. Other technologies are under research and development, as for instance Wet Air Oxidation (WAO), especially for wastewaters that contains high chemical oxygen demand.