Within the current authorization procedure "TNsG for data requirements for active substances and biocidal products (2000)", biocides applied for disinfection purposes or insect control in animal houses are to be studied on ultimate biodegradability underanaerobic conditions. Due to the lack of an established simulation test in liquid manures, the biocidal guidance documents recommend a screening test according to OECD 311 using digested sludge of a municipal wastewater treatment plant under optimized boundary conditions of an anaerobic digester.