Abstract: For the processing of waste oil, i.e. environmentally safe processing, a process and installation are used whereby the waste oil is preheated with the distillation gases and is then distilled itself by burning the distilled waste oil. The liquid and solid residues are exposed to the flame produced by the combustion of the distilled waste oil, while the gaseous residues are heated to over 1,200.degree. C. in a long-hold chamber constructed as a fume incinerator. In order to calcine the solid or burn the liquid residues, they are collected in the distillation chamber and transported via a rotating cylinder and a chute into the combustion chamber where they are then correspondingly calcined by the burner flame. In contrast, the gaseous residues are fed to a long-hold chamber, whereby the latter is a pipe system with a length of 75 m or more.