In this report the experts of the Umweltbundesamt describe processes and techniques applied in installations of the Austrian Slaughterhouses and Animal By-products Industries. The focus lies on environmentally relevant techniques and processes – either related to the consumption of energy and resources or related to emissions of pollutants. Predominantly affected by slaughtering and rendering processes is water, due to water consumption and emissions of organic pollutants in wastewater. Key parameters for wastewater emissions are COD/TOC, BOD, total nitrogen, total phosphorus, total suspended solids and low volatile lipophilic substances. Based on assessments of the techniques applied and associated consumption and emission figures, best available techniques for the Slaughterhouses and Animal By-products Industries are described.