In Austria, approximately one million tons of hazardous waste arises per annum, which requires a special technical treatment. According to current developments on the market, an increase of this amount can be predicted for the following years. Substantial parts of the treatment and disposal chain for hazardous wastes are chemical-physical treatment plants, where about 152.000 tons of waste are treated per annum. The treatment techniques of the plants have to be continuously adapted to the best available technique (BAT) to accomplish a proper treatment of different kinds of waste. Another important objective is legal compliance with all appropriate regulations by observing high standards during the treatment process regarding to the quality of the waste water, the quality of solid and pasty residuals and the purity of the waste-gases. In the course of this paper in hand, the best available technique for the treatment of fluid hazardous fluid wastes, in accordance with the applicable regulations, is defined. Furthermore this paper in hand contains an allocation of different kinds of wastes, by reference to their waste-code number, to the suitable treatment techniques, as well as technologies for waste and waste-gas treatment and an description of the current technologies for waste treatment used in Austria.