Recycling is fast becoming the backbone of the transition to a more circular economy for plastics. Yet recycling processes, too, consume resources, such as energy and water. After all, the washing line, for example, is an integral part of the plastics recycling process.
If sustainability is the goal, then both the process and the end product should be equally important - an insight that led the Germany-based Krones Group to take a closer look at the water consumption of the recycling systems it designs and manufactures. The company offers solutions ranging from separate washing and decontamination modules to entire recycling plants. According to Krones, its MetaPure technology, designed to recover PET and polyolefin bottles and containers, yields recyclate in a quality suitable for closed-loop applications.
The company has now turned its focus on its washing module’s water quality and consumption.
The wastewater produced during the process of recycling - during grinding in the wet mills and the washing step - contains, among others, organic residues of the packages’ content, for example, or cleaning agents from the washing process and printing ink particles removed from bottles and labels.
“In many recycling lines, the water is recirculated and treated in a bypass,” said product manager Astrid Kadlubski. As a result, the dirt load of the process water continues to rise and ultimately impairs the end product’s quality, she explained. In collaboration with a partner, Krones has now developed an intelligent solution for the complete treatment of the washing and mill water. The development successfully reduces both freshwater consumption and wastewater quantity. It also ensures, said Kadlubski, that the wastewater discharged into the municipal system complies with the relevant specifications, even with the ultra-stringent regulations applying in Germany.