Advances in automated processing are transforming the art of materials recovery.
Organic waste: that’s another matter, especially if you’re in recycling. It’s food, organic and otherwise, and assorted biologic debris. In the trash, it soaks your paper, dirties your cans and bottles. Commingled in the recurring mega-tonnage of refuse arriving at a materials recovery facility (MRF), it causes no end of trouble and expense in trying to remove it. That is why tens of millions of Americans dutifully separate recyclables. We haul the blue bin to curbside each pickup day. That is why nearly every city has invested millions of dollars in truck fleets and labor to separate these dirty wastestreams and process them.
Recyclers, environmentalists, citizens, and MRF operators overwhelmingly agree on the desirable outcomes of separated recycling. But there’s a ferocious debate and political struggle brewing over how best to do it.
The main problem: Sorting garbage by you and me is so imperfectly done. Even in exceptional cities where two-thirds of us trundle out bins for respective type collection, the actual results are never really good enough.
So, for a few years now there’s been concerted effort, in the US but more especially in several European countries, to devise systems that can replace the hit-or-miss haphazardness of citizen effort and somehow sort, separate, clean up, and process the entire dirty wastestream, affordably and more or less automatically.
In Europe, tough regulations mandate it. Subsidies pay for it. So, advanced engineering and technologies are making it happen there. Touring groups of envious US waste managers routinely discover this.
It’s also beginning to happen here. On the drawing board, or being piloted in a few sites, there are MRFs that will revolutionize dirty waste management. Ultimately they will divert not the stubbornly fixed 30-something percent national average, or 40, 50 or even 60%—but 90% or more. Whatever isn’t recovered for sale will be rendered as fuel, except for a tiny fraction.
It’s happening, but so too is pushback, criticism, and crafty opposition. America, ever a free-for-all of competing agendas, has folks earnestly vying (and lying?) for the status quo, or for zero waste, or simply for better optimized recycling—and several stops between.
Conventional curbside recycling by citizen sorters seems sort of stuck. Landfilling is not limitless; filling isn’t sustainable. How do you take trash to the next level? Whither the dirty MRF? This is the topic debated below.
Before looking at the emerging future of dirty MRFs (DMRFs), a quick look at their recent history will be helpful. The following perspective is offered by Steven Viny, CEO of Envision Holdings, of Cleveland, and operator of a couple of DMRFs in rural Ohio. His firm also makes and installs equipment for other MRFs.
In the early 1980s, he recalls, DMRFs typically removed ferrous metals and prepared “refuse-derived fuel.” That’s a fancy phrase for incineration, which was about all they did.
Then, as aluminum and paper recycling came into fashion, engineers pondered making mechanical systems to remove more of what was valuable and reusable. To do this sorting required a common denominator, but none could be found. So engineers hit on the idea of reducing everything to a single “digestible” size, not unlike how we chew our food. Thus, giant hammermill shredders were placed at the front of unsorted MSW.
Unfortunately, these gagged on things like chunks of concrete, propane tanks, and other heavy objects. Explosions and breakdowns followed, so this model was ultimately abandoned.
In the 1990s came the thought, Isn’t it easier to separate out a cardboard box when it’s whole, versus collecting lots of little pieces of it? “So,” Viny continues, “basically, shredders were moved to the end of the line.” Hand separation and some primitive automation were introduced. “Advances such as eddy-current separators for aluminum, more powerful rare-earth magnets for ferrous metal, and both drum and vibrating screens to remove dirt and organics were integrated in the typical DMRF,” he adds.
Another challenge in those days was financial. Curbside recycling was catching on as a competitor. In DMRFs, sorting now added a cost, yet the resulting market value of the recovered materials was comparatively low, being still dirty. Examples of DMRF commercial failures in Georgia and Arizona are recalled by another MRF equipment maker, speaking on background. In the latter location, the arriving single wastestream turned out to be routinely contaminated with heavy metals and hazardous chemicals. “Somebody should have told them that it’s impossible [to sort and recycle] with all that stuff in there,” he says.
More recently, in 2011, the financial failure of a huge, $310 million waste incinerator in Harrisburg, PA, forced the city into bankruptcy.
Another commenter on the early days, George Dreckmann, formerly recycling director for the city of Madison, WI, remembers how the city of Chicago, at that time, ran several DMRFs. Eventually, all failed. Dreckmann, who is now Madison’s strategic initiatives coordinator for the Public Works Department, was contacted for input here because he’d posted unflattering comments about DMRFs in a forum for recyclers. Dreckmann admits that his opinions were shaped by such early setbacks, yet thinks he probably still reflects views widely shared among colleagues. As he explains, “The basic problem with [DMRFs] still exists. Once you mix [recyclables] in with garbage, I don’t know how you can take out a clean and good product to market. There’s an awful lot of liquid in a garbage truck… meat juices, paints… that is going to contaminate your paper. That’s my biggest concern, along with the challenge of how to sort it.”
China, he adds, the 800-pound commodity buyer, “is now clamping down on the quality of what’s coming from single-steam MRFs.”
He concedes he’s not up on the latest tech marvels, but Dreckmann is familiar with organic sorting because Madison, rather ironically, runs a single-stream collection system. “I’m regularly beat up by some of the purists in our business, as a defender of single-stream,” he notes.
Viny concludes by describing today’s technology, in which he’s quite well versed, as something virtually unrecognizable compared with early days. “Between magnets, eddy-current separators, ballistic separators… light fraction screens… and near-IR used to separate out commodities like paper and plastics, the combination and integration of those has really evolved to a point where it’s very sophisticated, very accurate, and capable of very high levels of landfill diversion,” he says.
Viny touts and defends his own DMRF operations: “In 20 years we have never had a load of recyclables rejected. Not even once.” In fact, buyers often prefer his product because he does a “positive sort” that selects specific items to gather, rather than the conventional “negative sort,” which eliminates what’s undesired and keeps what remains. “If we miss some product while doing a positive sort, our capture rate is slightly reduced. If a negative sort misses some material, they end up with contamination in the baled product,” he adds.
Viny sums up: “What was once a problematic business has now turned into something that’s bulletproof. If you’ve got a population center of at least 120,000, you really need to take a look at the dirty MRF. The economics are compelling.”