The Rotary Disc Screen
After passing under the electromagnet, the remaining shredded refuse drops into the primary rotary disc screen separator, which removes abrasive grit and dust; this machine helps to reduce wear on equipment, prevent damage to electrical wiring and connections, and to decrease maintenance costs.
The disc screen consists of a series of revolving, star-shaped metal plates that bounce the largest pieces of refuse across the top and allow the smaller pieces to drop through. These smaller pieces, most less than 1.5 inches in size, are transported on conveyors to a secondary disc screen that further separates out the grit and dust consisting of materials that don't burn well. The grit is then conveyed to a reject bin, and later landfilled. The smaller, combustible fraction continues on through the process.