The Pre-sort staff is the MRF’s (Material Recovery Facility) first line of defense against things that can damage the system or don’t travel through it properly.
The staff looks for things like plastic bags, wire, large pieces of metal, and electronics that are all prohibited from the system. Things that are accepted for recycling in single stream programs like large plastic buckets and containers, do not conform to the size separation in the next part of the system, the OCC Screen. This is why they are pulled out in the Pre-Sort. These items are things like: 5 gallon plastic buckets, large detergent bottles, and large kitty litter containers.
After the Pre-Sort, the materials fall off the belt into the OCC Screen. OCC means Old Corrugated Containers. That machine does more than its name suggests.