Method and plant for biological treatment of aqueous effluents for purification thereof

摘要

The invention relates to a method for the biological treatment of effluents contaminated with impurities of urban or industrial origin, characterised in employing a single aeration tank ( 1 ) with a high mass charge in which the raw effluent or mechanically pre-treated effluent is mixed without previous decantation with a free microbial culture of the activated sludge type, growing in a lightly aerated medium, of the order of 0.1 to 0.2 kg O₂/kg BOD 5 removed, the organic charge applied having a value equal to or greater than at least 2 kg COD/kgSM/day, preferably equal to or greater than 4 kg COD/kgSM/day, the hydraulic residence time for the raw effluent in the single aeration tank being between 30 and 90 minutes, preferably between 40 and 60 minutes.