Cleaning contaminated plastic film with water only transfers the contamination from the film to the water. Water treatment is an added expense. “But when you clean dry, you remove the problem,” says Heinz Schnettler, engineer at the Systec div. of Duales System Deutschland, which administers the “Green Dot” program for recycling packaging waste in Germany. He also notes that if you remove paper labels while dry, you preserve their value for waste-to-energy incineration. If paper gets wet, it gains weight and costs more to dispose of.
Systec cleans film and flake with a Waterless Mechanical Purifier, which comes in two sizes, both with throughput capacity of 2000 to 4500 lb/hr of plastic, but one provides more cleaning time. The MR 75 is 3 meters long, has a 100-hp drive, and tackles plastic with average contamination. The MR 110 is twice as long, has a 150-hp drive, and tackles difficult problems like removing paper labels. A complete system with the larger MR 110 unit costs about $133,000. With the MR 75, it’s $20,000 less.
Systec has 26 dry recycling units installed worldwide that are reclaiming film, post-consumer mixed plastics, and plastic/paper composites. One system in Canada removes paper labels from PET flake. Systec recently gave a license to shredder maker Kurimoto Ltd. in Osaka, Japan, which has sold two Systec systems so far.
Cleaning with air
The Systec process starts with a buffer silo that holds 4 to 8 m3 of shredded film. Feed augers inside the silo are configured for specific film weights from 10-micron stretch film to heavy industrial film.