System for cleaning rivers and waterways in general, characterized in that it comprises one or more floating modules, wherein each module comprises: - at least one floating body suited to float on water; - at least one rotary body constrained in any way to said floating body, so as to be able to rotate with respect to the latter around an axis orthogonal to the flotation plane of the floating body; - means suited to set said rotary body rotating owing to the thrust exerted by the current of the waterway; - means for anchoring said floating body to a fixed point; and wherein said rotary body comprises projecting elements having at least one radial component and configured in such a way that they are at least partially positioned on the water surface so that, when said rotary body rotates owing to the thrust exerted by the current of the waterway, said projecting elements move any floating debris in a direction which is determined by its rotation direction, towards an accumulation or recovery area, and wherein said anchorage means of each of said module comprise at least one cable joined to said floating body and constrained in any way to a fixed point or to the bottom of the waterway, and wherein said cable is flexible, in such a way as to allow the module to move on the water surface within a predetermined area due to the effect of a thrusting action for example in the case in which they intercept trunks or branches or boats of any type, and wherein it comprises a plurality of said modules and means suited to retain said modules arranged near one another and substantially aligned according to at least one direction, in such a way that, once positioned in a waterway and aligned crosswise with respect to the flowing direction of the water, the floating debris intercepted by a module is moved in said direction _to the operating area of the adjacent module, towards said accumulation or recovery area. - at least one floating body suited to float on water; - at least one rotary body constrained in any way to said floating body, so as to be able to rotate with respect to the latter around an axis orthogonal to the flotation plane of the floating body; - means suited to set said rotary body rotating owing to the thrust exerted by the current of the waterway; - means for anchoring said floating body to a fixed point; and wherein said rotary body comprises projecting elements having at least one radial component and configured in such a way that they are at least partially positioned on the water surface so that, when said rotary body rotates owing to the thrust exerted by the current of the waterway, said projecting elements move any floating debris in a direction which is determined by its rotation direction, towards an accumulation or recovery area, and wherein said anchorage means of each of said module comprise at least one cable joined to said floating body and constrained in any way to a fixed point or to the bottom of the waterway, and wherein said cable is flexible, in such a way as to allow the module to move on the water surface within a predetermined area due to the effect of a thrusting action for example in the case in which they intercept trunks or branches or boats of any type, and wherein it comprises a plurality of said modules and means suited to retain said modules arranged near one another and substantially aligned according to at least one direction, in such a way that, once positioned in a waterway and aligned crosswise with respect to the flowing direction of the water, the floating debris intercepted by a module is moved in said direction _to the operating area of the adjacent module, towards said accumulation or recovery area.