Abstract: A system and apparatus for size reduction and classification of solids particles to aid in their disposal. The system includes mixing the solids particles in a viscous liquid to form a slurry in a receiving tank, passing the slurry through a series of initial screens and magnets, and circulating the slurry through a series of reduction tanks to a holding tank by vertical fluid mills. The vertical fluid mills include a slurry inlet and outlet and have a rotating shaft to which is mounted a series of rotating perforated disks which rotate in close proximity to and between a pair of stationary blades. The disks and blades are situated between series of impellers mounted on the rotating shaft. The reduction tanks include screens for solids classification and recirculation of the solids particles.