Maximizing Efficiency and Safety at MRFs

The Occupational Safety and Health Administration (OSHA) points out on its website that while recycling is good for the environment, it can be dangerous for workers. Certain materials in the wastestream directly pose hazards to workers. Additional hazards include vehicle traffic, moving machine parts, unexpected machine startup, lifting injuries, slips, trips, and falls.

There have been six baler-related deaths or injuries at a recycling or waste management facilities nationwide since 2000, according to OSHA. In the latest, a worker at a Winter Garden, FL, recycling operation was killed while trying to clear a jam in a massive cardboard compactor and bundling machine.

The Changing Wastestream Complicates the Situation
“An increase in small cardboard is noticeable as consumers are increasingly ordering online and have goods shipped to their house,” says Rutger Zweers, Stadler USA sales director, who adds that material composition strongly changes per location, city or state.

“Newspaper is dropping fast due to online news sources; this is the biggest driving factor for planning future systems,” explains Brian Schellati, director of business development for VAN DYK Recycling Solutions. “We see a slight increase happening with office-type paper as more home offices become established, but this is very gradual.”

Schellati also notes a “definite increase” in cardboard due to more online shopping, “but at a much slower rate than the decline of newsprint.”

Other materials are fairly consistent but can fluctuate depending on the economy. More containers appear in the wastestream as a result of increased consumption in a better economy, he adds.

“Single-serve plastic bottles, larger packaging for bulk purchasing, e-waste, plastic film/bags, and rigid plastic film—the latter two in particular—are becoming hot-button issues as states have been banning plastic bags and companies are running to find ways to recycle both the plastic bags and rigid plastic film,” says Michael Drolet, solutions sales manager for Steinert US.

Seasonal changes also impact the waste­stream, he points out. “After Christmas, there are cardboard boxes and wrapping paper to sort. The designed systems should be able to absorb surges of seasonal material in order to stay flexible. Cities have been changing their collection programs to make it easier for residents to recycle. By going to a single-stream program, all items are mixed in the same recycling bin for separation. The system should be designed to accommodate not only different materials, but different levels of residue, too.”

Matthew Everhart, sales manager for Vecoplan’s waste division, says that the advent of lighter packaging and bulkier container goods such and the near ­”disappearance” of thick wall plastics and news­paper from the wastestream has been the most significant change affecting the layout of single-stream MRFs.

“Traditionally, there were cardboard screens at the front of the system and then behind that was the paper streams,” he adds. “With the change in the paper because of not having news, that’s made a difference in how the material flows through them.”

Another influence in MRF design is “the increasing popularity of mixed waste,” continues Everhart. “The way that you screen and process mixed waste, versus the way you do single stream, is dramatically different. The volumes are significantly higher, and the amount of contaminated material that has to be moved is significantly higher.”

Don Suderman, product manager for Bunting Magnetics, notes that the composition of material received at municipal waste recycling facilities changes as packaging technology evolves and as citizens demand that more of their waste be recycled. “Recycling facilities today are faced with an ever more complex input mix, as consumer product brand managers use new materials in their packages, and as engineers produce new devices.”

The growth of online sales, from businesses such as Amazon, means that municipal waste facilities have more corrugated material to recycle, Suderman points out. “Because corrugated and cardboard are easily reused, significant demand exists for clear recycled material. Passing bales of corrugated through a tunnel-style metal detector ensures a quality recycled product is shipped from the recycling plant.”

Ferrous metals are being replaced with nonferrous material, including sturdy new plastics and composites, as well as nonferrous metals such as stainless steel and aluminum, Suderman says. “Non-recyclable plastic materials, with differences indiscernible to the ordinary citizen, are replacing recyclable paper. These changes mean that equipment once capable of detecting and removing ferrous metals may no longer do the job. These developments call for ever more sophisticated metal detection and magnetic devices to maintain product purity and maximize recycling output salability.”

Mix changes also may mean than facility equipment is insufficiently protected, says Suderman. “Conventional wisdom calls for removing metal from the stream, for example, to improve product purity while the most important reason may be to reduce the chance of damage to equipment caused by foreign material that should have been detected and removed earlier in the process,” he adds.

Roy Miller, vice president of engineering for Bulk Handling Systems (BHS) notes that the single-stream market has become “relatively mature” with the difference being declining fiber content and a high interest in organics processing. “Even in areas where there is not a competing single stream program, we see modest amounts of conventional recyclable products,” he says. “They are largely the same products you find in a single-stream system.” MSW_bug_web

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