METHOD FOR THE BIOLOGICAL TREATMENT OF EFFLUENT AND PLANT FOR IMPLEMENTING SAME

摘要

The invention concerns a method for the biological treatment of an aqueous effluent for its purification whereby the effluent is contacted with activated sludge in at least a biological treatment pond (1), the biologically treated effluent is then clarified (2), part of the excess sludge derived from clarification (2) being returned (6) to the top of said pond. Said method is characterised in that it consists in retaining a second part of the excess sludge derived from clarification (2) in at least one aerated pond for biological activation (3) to constitute a biomass reserve and, when said aqueous effluent contains additional polluting agents, in using this biomass reserve for treating said additional polluting agents.