A plant (1) and method for recovering plastic materials of post-consumption materials, such as vehicle bumpers and tanks, in the plant, downstream of the volumetric reduction grinder (2), there is provided an intermediate grinder (6) and the washing vat (9) and the centrifuge (12) additionally being arranged upstream of the windmill/granulator (14), while in the method, an intermediate grinding step is arranged upstream of the grinding/granulation step and a subsequent washing step and separation in the vat of the parts of foreign materials through the difference of specific weight, including ferrous, non-ferrous materials and alloys thereof, of the material made of intermediate size, before the grinding/granulation step through windmill/granulator, wherein the washing and centrifugation water is subjected to a continuous purification cycle. In order to increase the productivity of the plant and reducing the maintenance times, the conveying elements for transporting the material are provided mobile, mounted on swivel wheels.