Fine screening is the second mechanical pre-treatment process allowing finer separation than coarse screens of the solid waste contained in the raw water. Filtration is carried out by a 6 mm to 0.25 mm opening using perforated sheet or wedge wire mesh (also called johnson mesh). Fine Screens are most of the time automated thanks to a motorization of the system of collection by a spiral, screw, drum or scraper. Manual solutions also exist requiring the action of an operator for a more affordable cost. The solid waste can then be discharged into a compaction system allowing a reduction in weight / volume and optimal dryness.