Abstract: The invention is designed for the treatment of household and industrial sewage, mainly for the biochemical treatment of high-contaminated sewage produced by those enterprises referred to the food, chemical, pharmaceutical and microbiological industries. The installation contains a primary purification stage biocoagulator (3), a secondary stage biocoagulator (14) whose sediment is introduced into a fermenter (17). Clarified effluent from biocoagulator (14) and fermenter (17) is further introduced into a pump plant (33), whereby effluent is pumped into a biofilter (39) and further into a combined device (44) of the same design as fermenter (17)—irrigation system, artificial charge, aeration columns, settling section. Clarified effluent from combined device (44) is finally processed into a tertiary purification bioreactor (50).