Analyzing modern MRF management

In recent years, material recovery facilities (MRFs) have had to adjust to what is commonly called the "evolving ton." Commodities that MRFs recycle today are fairly different from what they recycled even five years ago, and today’s commodities are likely somewhat different than what will be collected and sorted at MRFs in a few years.

During the WasteExpo Together Online Conference Sept. 15, several panelists discussed the evolving ton and how that’s affecting infrastructure and technology decisions at MRFs in a session titled The New Modern MRF – Shaping Today’s MRFs in the Wake of COVID-19. Panelists included Nathiel Egosi, president of Melville, New York-based RRT Design & Construction; Brent Hildebrand, vice president of recycling at Vaughan, Canada-based GFL Environmental Inc.; and Chris Hawn, CEO of Plessisville, Quebec-based Machinex Technologies Inc.

Hawn of Machinex said polypropylene (PP) is becoming a more important commodity for MRFs to sort, adding that there is a lot of grant funding available to facilities looking to better sort PP.

While old corrugated containers (OCC) are becoming much more prevalent in residential recycling streams, the presence of sorted residential news and some office paper grades is diminishing. Egosi said most MRFs are designed to sort two to three grades of recovered paper in addition to OCC, but he said a lot of those other grades are getting clumped into mixed paper in light of less incoming material. He added that glass may also shift to a different type of collection and sortation outside of MRFs in the future.

“In different parts of the country, such as Utah, glass is not recycled in MRFs at all. In Europe and many countries, glass is not recycled in the MRF, either. It’s collected separately,” Egosi said.

Additionally, there is the issue of used beverage containers (UBCs) getting lost in other streams in today’s MRF.

With the evolving ton, MRFs are having to make changes to technology where (and if) they economically can. Panelists discussed how optical sorters have become much more commonplace in any given MRF.

“The reason we see optical sorters is because of their efficiencies in distinguishing items from other contaminants,” Egosi said. “They are relatively low maintenance.”

Opticals can help with the issue of recovering UBCs that may otherwise be lost in fiber lines.

“You’re seeing more optical sorters on the fiber screen doing the job of removing contaminants and sending what we’re calling contaminants back to where they need to be—which is the container stream—to be recovered,” Hawn said.

Robotics are another tool that is being added to more MRFs to help sort the evolving ton.

Hawn said robotics for MRF applications are no longer in the “infancy” stage; they are in “adolescence” and still have some limitations.

“It’s not like an optic,” he said of robotics. “An optic works in its most efficient form when you spread material out. To perform that task, you need a belt speed human sorters can’t pick. A robot by the same accord cannot necessarily keep up with the speed of those belts,” he said, noting that robotics are limited to about 200 feet of belting per minute, whereas optical sorters can work with much faster belt speeds.

He continued, “That being said, though, the number of [robotic units] that get put into place come into play, we can spread belts, make wider belts. In the end, you can use them in a series. Right now, you see most of the robots being put on the container side of the business. … [A]lso they will always work in conjunction with optical sorters. Opticals and robots work hand in hand now and into the future. I believe you’ll be able to see tandem robots able to handle wider belts at a little higher speeds than they currently do now.”

Regardless of technology added to enhance MRFs to be able to deal with the evolving ton, Hildebrand said a “great maintenance program” is key to success in the modern MRF.

“There’s no substitute for a great maintenance program in these facilities,” he said. “As far as different things manufacturers are doing, yeah, there are things happening that are helping with eliminating some of the downtime. Manufacturers are really good at designing systems that are more easily maintained. When you design a system, that’s what I look for—what can you do to make maintenance easier and quicker to get back up and running?”