Abstract: Provided is a method for performing thermal hydrolysis of sludge in a cyclic manner. A sludge stream is directed into one reactor during a first cycle and in a second cycle sludge is directed into another reactor. Each reactor has a sludge recirculation loop associated therewith. Flash steam from one reactor is transferred to the other reactor to pre-heat the sludge. The sludge in each reactor is recirculated through the circulation loop during each cycle of thermal hydrolysis. Live steam is directed into each reactor to raise the pressure and temperature within the reactor in order to enable the thermal hydrolysis process to take place.

Abstract: The invention relates to a method for producing non-putrescible sludge and energy, wherein said method includes the following steps: (i) producing digested sludge by means of primary sludge digestion; (ii) producing a first aqueous effluent and digested sludge, which are at least partially dehydrated by a first liquid-solid separation of the digested sludge produced in step (i); (iii) producing digested sludge at least partially dehydrated and hydrolysed by thermal hydrolysis of the at least partially dehydrated digested sludge produced in step (ii); (iv) digesting the at least partially dehydrated and hydrolysed digested sludge produced in step (iii); wherein said method further includes a step of recovering the biogases formed during said digestion and said primary digestion, and a step of producing energy from said biogas, including a first sub-step of producing the energy required for implementing said thermal hydrolysis and a sub-step of producing excess energy, the entirety of the biogas being used for