PLANT AND PROCESS FOR TREATING A LIQUID EFFLUENT COMPRISING A METHANE FERMENTATION, A BIOLOGICAL TREATMENT, A DIGESTION OF METHANE-FERMENTED SLUDGES AND OF BIOLOGICAL SLUDGES, AND A METHANE FERMENTATION OF DIGESTED SLUDGES.

摘要

The invention relates to a process for treating liquid effluent, said process comprising a step of methane fermentation of said effluent within a methane fermenter (32) producing biogas, methane-fermented sludges and a methane-fermented effluent, a step of biological treatment of said methane-fermented effluent within a biological treatment zone (34) producing biological sludges and a treated effluent, a step of extraction of thickened biological sludges from said biological treatment zone (34), a step of anaerobic digestion of at least one portion of said methane-fermented sludges and of said thickened biological sludges within a digestor (44) producing biogas and digested sludges, a step of recirculating at least one portion of said digested sludges to said methane fermenter (21), and a step of extracting at least one portion of the digested sludges.