DESCRIZIONE
Water treatment device comprising: a body defining a duct (2) for a water flow; a bladed assembly (5) contained in said body and contacting said water flow, said bladed assembly comprising a plurality of blades (6) aligned along the flow direction and rotated one to another by a pitch angle so that a tortuous path for said water flow traversing the duct is generated between the blades, a convergent-divergent section (12) downstream said tortuous path and traversed by the water flow. Method for treating water by means of hydrodynamic cavitation with ultrasonic pressure waves generation.