Until January 2021, polypropylene (PP) waste was not in Rumpke’s “acceptables” list, but watching its worth spike this past year or so, the company decided to make a major investment that’s enabled it to process 80 to 100 tons a month at its Cincinnati materials recovery facility (MRF).

With a matching grant from the Recycling Partnership, Rumpke invested a total of $1.6 million in three Machinex SamurAI robots that make about 240 picks a minute of yogurt, sour cream, and butter tubs and lids among items made from PP. Since those first three robots debuted, a fourth one was added that picks high-density polypropylene (HDPE) natural milk jugs.

The AI system (camera) takes pictures by shape and color; that data is downloaded, and robots recognize materials by these features.

“We chose robotics because the line we wanted to put them on was perfect. We have a single belt and robots fit nicely over it. They are positioned at the end of our container line and pick polypropylene right off the belt,” says Jeff Snyder, director of Recycling Rumpke Waste & Recycling.

Though they had to adapt the bunker chutes and widen the belt so materials could be spread out, enabling robots to pick individual items. And they added belts to convey material to the proper bunker.

“We are doing an analysis to understand how much polypropylene we get, how much we miss, and how much will increase now that we take tubs. But now robots can handle all that comes our way,” Snyder says.

The transition was somewhat gradual. Workers began hand sorting PP tubs this past January to prep for the technology’s official June launch. And they brought in the cameras before the robots as the AI system needed time to train itself and teach these automated sorters what to pick.

After watching the SamurAI perform for a while, Snyder and his team determined buying another robot to sort HDPE natural was the next logical move – not just for its value but because of the way it sorted on the plant’s system. The heavy jugs ride along a conveyor and after an optical sort make their way to the robot where color is separated from natural jugs.

Although optics have been in the industry for many years, they are constantly evolving and work nicely with the robots.

“The beauty of both technologies is that they are adaptable to the ever- changing material stream and commodity focus,” says Chris Hawn, CEO of Machinex Technologies.

He points to what these capabilities mean for the first time for that initial material Rumpke was after: “If you roll the clock back only a couple of years, PP was nothing more than a commodity buried in the mixed plastic bale. Today, both robots and optics are focused on extracting it as a single commodity.”

PureCycle Technologies is one of Rumpke’s five end users. It’s using PP as feedstock at its purification plant in Ironton, OH that transforms plastic waste into pure recycled plastic that’s free of color, odor, and other contamination.

“The technology that Rumpke is now using has helped create true number 5 (PP) bales versus mixed bales that include numbers 3 through 7. This helps streamline PureCycle’s process and makes creating our ultra-pure recycled plastic more efficient,” says Anna Alexopoulos Farrar, Global Communications manager, PureCycle.

She projects that innovations such as robots and AI will continue to expand the range of materials that can be collected and processed as well as be “game changing” for manufacturing.

“PureCycle is focused on implementing a “born digital” strategy to streamline construction and operational readiness activities. We are leapfrogging to the latest generation of automation technology, employing virtual reality, augmented reality, and artificial intelligence so projects can be completed faster and operate with world-class performance,” Farrar says.

One reason Rumpke chose Machinex is that in addition to gaining knowledge from AI crossing its line, operators gain from Machinex SamurAI robots in other locations because they tap into a shared database.

“If a new product in Chicago comes to Cincinnati we can go to the cloud and download information to get the size, shape, and color of that particular product. So, we do not have to train our robot to recognize it,” Snyder says.

While SamurAI is one robot and vision system, it has broad applications, as it can work with any material that has a visual difference.  Among applications are polyethylene terephthalate (PET) quality control (QC), HDPE QC, HDPE color sort, PP, mixed plastics, and used beverage cans QC.

Rumpke is one of 13 U.S. MRFs who collectively received $4.2M in grants this past year from The Recycling Partnership’s Polypropylene Recycling Coalition to improve access to recycling of this material. Coalition members also invested more than $32M in about the same timeframe to increase reclamation capacity and prepare for new supplies of PP.  

Katherine Huded, director of Circular Ventures, The Recycling Partnership, explains why the national nonprofit is vested:

“Polypropylene is the third highest volume rigid plastic packaging found in the recycling bin. But because of its variety of formats and uses and its relative newness to the recycling stream, it is overlooked, despite increasing demand for it as a recycled material. Brand commitments to increase the recyclability and recycled content of their products and packaging has spurred an immediate need for equipment upgrades in some U.S. MRFs to effectively capture and return polypropylene to the circular economy. We are rapidly issuing grants to help catalyze domestic investment … and to help MRF’s better capture and sort this important recyclable and divert it from landfill.”

As an operator at one of the first MRFs in the Midwest to invest in robots, Snyder says they are working well.

“We are pulling polypropylene and shipping to end users, which we are excited about. But it’s a process. You don’t go all in on day one. We will continue to look closely at our MRFs and try to identify recyclables with end markets. And we will constantly look at technology to get materials to that end market.”