Items whose dimensions are clearly more 3-dimensional than 2-dimensional (CASS > 20)
Early in the MRF sorting process, 3-dimensional items (containers) are separated from 2-dimensional items (paper). It is important that they sort property and do not cross-contaminate. Most HDPE bottles are more "round" (3-D) than "flat" (2-D) and therefore sort correctly.
Items less than or equal to 7.5 liters (2 gallons) in volume
Recycling machinery, particularly automatic sorting equipment, is not large enough to accept items larger than two gallons. Because larger containers jam the systems, most MRFs employ manual sortation before the automatic line to remove the large items. These items are recovered in a stream of bulky rigid containers that are sold and processed as polyethylene since the vast majority of bulky rigid items are comprised of this polymer. Other polymers including PET either negatively affect or are lost by the polyethylene processing.
Items that measure larger than five centimeters (2 inches) in two dimensions
Small size boundaries are of concern because the industry standard screen size potentially loses materials less than 5 cm to a non-plastics stream, causing contamination in that stream, or directly to waste. Testing can determine the impact of the size and shape of a container on sortability.
REQUIRES TEST RESULTS
Items more 2-dimensional than 3-dimensional (CASS > 11 but < 20)
Aside from not being captured for the HDPE stream, non-conforming items that are more "flat" can cause contamination in the paper stream. If items are not captured and directed into the HDPE stream, they are not recycled. Items should have a minimum depth of two inches for proper sortation.
*Under Development - Definitive Test
Evaluation of 2D/3D Sorting Potential for Articles (SORT-B-0X)
Items smaller than five centimeters (2 inches) in 2 dimensions
The industry standard screen size potentially loses materials less than 5 cm to a non-plastics stream, causing contamination in that stream, or directly to waste. Testing can determine the impact of the size and shape of a container on sortability.