Method for the treatment of complex waste

A method for treating a mixture M1 comprising at least organic matter, said method comprising:

• a) hydrolyzing mixture M1 at a temperature ranging from 70 to 165° C. and at a pressure ranging from 1 to 8 bar to obtain a hydrolyzed mixture M1h, the ratio between the viscosity of mixture M1 and the viscosity of mixture M1h being at least 2 ;
• b) pressurizing mixture M1h at a pressure ranging from 20 to 350 bar to obtain a stream M1p;
• c) heating mixture M1p to a temperature ranging from 250° C. to 450° C., to obtain a mixture M2;
• d) solubilizing at least one fraction of mixture M2 , optionally heating at a temperature ranging from 250 to 450° C., and separating to obtain a stream M4 enriched with soluble materials and a stream M3 depleted of soluble materials, said step d) being carried out in one or more reactors with an overall hydraulic residence time less than or equal to 20 minutes;
• e) cooling and expanding at least one fraction of stream M4 enriched with soluble materials to obtain a stream M5;
• and
• f) digesting at least one fraction of stream M5.