Abstract: Sludge dewatering process assisted by flocculating reactant, said process comprising an injection of flocculating reactant into the sludge and a step of dewatering said sludge, characterized in that it comprises a preliminary step that consists in mixing said sludge in a mixer (4) comprising a cylindrical chamber (4a) equipped with blades (4c) rotatably mounted on a shaft (4b) rotating at a speed of rotation of between 500 rpm and 4000 rpm, so as to destructure the sludge and reduce the viscosity thereof, and in discharging the sludge from said mixer (4) via a network (11) to said dewatering step, and in that it comprises a step of depressurizing said mixer (4) and said network giving rise to the lysis, by cavitation, of said sludge, said depressurizing step being carried out over a period of at least 0.1 second. Corresponding plant.