Passing the sniff test: Odor reduction opens new possibilities

Anyone who has been on the loading dock in summer when bales of postconsumer plastic scrap are unloaded knows that the stench can make you wish you had skipped breakfast. But thanks to some emerging technologies, the smelly business of recycling does not mean recycled material has to stink.

Two companies have introduced technology to make recycled plastic smell like virgin plastic. This is fantastic news for the entire recycling supply chain because it makes more material available for more end uses. It adds value.

Starlinger & Co. GmbH and Erema, both based in Austria, unveiled the technologies in October at the K show in Germany.

The importance of this technology did not register with me until recently when Alan DiUmberto, sales manager for the recycling division of American Starlinger-Sahm Inc., let me sniff a container of recycled pellets made from high-density polyethylene gas tanks. They smelled like gasoline. Then he let me smell pellets from the same source that had been processed using Starlinger’s new Smell Extraction Unit. There was no gasoline odor.

The Starlinger process involves heating and homogenizing recyclate, then removing gases with a Starlinger degassing module that significantly increases the melt surface of the material. Treatment in the Smell Extraction Unit is the final step. Different sources of odors are removed in each step.

Erema’s new system, called ReFresher, is downstream from the extrusion process. It uses an airflow system that blows the volatile materials that cause odor off of the heated pellets.

These new technologies take the industry one small step closer to a major goal—recycled material that is equal to virgin material and works in any application.

Someday we may look back at these technologies and wonder how the plastics recycling industry evolved to this point without them.

We don’t know the exact amount, but some of the collected material with odors from chemicals in food, cosmetics, household products or detergents is not recycled or is relegated to products where odor does not much matter, such as pipes or agricultural film.

But if the odor is removed, that material could end up in an automobile interior, in home or medical products or in containers where aesthetics are important.

“I am sure that the ReFresher will be another boost to the use of recyclates from postconsumer material,” says Clemens Kitzberger, postconsumer business development manager at Erema. “Whether it is in supermarkets or homes, I assume that we will come into contact with this type of odor-treated recyclate more and more in the future.”

Starlinger’s DiUmberto agrees. “This process will create commercial markets for materials such as fuel tank recyclate, which did not exist before because of the odor issue,” he says.

That is good news for the plastics recycling industry.