The study of the effect of protein-lipid components on the vital functions of activated sludge is promising from the standpoint of developing recommendations for preliminary treatment of highly concentrated effluents entering the biological oxidation line. Objects of research: 1. Active sludge (sludge index 92.0-125.0 cm3/g; mass concentration 4.0-5.5 g/dm3; sedimentation rate 0.5-0.6 cm3/min), 2. Enzymatic dry peptone for bacteriological purposes (13805-76 State Standard). Research methods: FR 1.31.2008.04397, FR 1.31.2008.04398, FR 1.31.2008.04400, microscopic examination of specimens for the purpose of hydrobiological research, laboratory installation, including a container for dosing waste water, aeration tank - mixer, a container for settling excess activated sludge, a compressor. The conditions under which the biooxidation was carried out were as follows: the flow rate into the aeration tank was 0.5 dm3/h, the air consumption for aeration of one aeration tank was 2 dm3/min, the operating mode was continuous, the aeration was fine-bubble, uniform, intensive, the study time was 5 weeks. The study of the effect of the content of the protein-lipid component in the effluents on the main hydrochemical and hydrobiological indicators of the state of the activated sludge biocenosis was carried out using model waste water containing enzymatic peptone C = 500 mg/dm3, C = 1000 mg/dm3, C = 2000 mg/dm3, C = 3000 mg/dm3, C = 4000 mg/dm3. The data obtained indicate an irreversible negative effect on the hydrochemical and hydrobiological parameters of activated sludge biocenosis with a protein-lipid component content of 3000 mg/dm3 and more. However, when the content of the protein-lipid component is less than 1000 mg/dm3, stable dynamics is observed both in hydrochemical and hydrobiological indicators