Every other week in the city of Pittsburgh, 14 trucks per day are sent on routes that each include 900-1100 stops. At the different stops, the trucks may encounter a few small blue plastic bags, or they might find a large blue can or bin holding loose plastics, glass, and cardboard. An important yet largely thankless job, collectors work with materials that may be dripping with water from a heavy rain, or may be scattered around a curb, or they may be improperly contained—leading to confusion as to whether or not the materials were actually meant for them. These crews are our recycling collectors, and when their routes are done, they deliver an average of 60 tons of recyclables per day to a materials recovery facility, or a MRF (say “murf”).

Have you ever wondered what happens after that point? I tend to set out my blue bags at night, and *magic* they’re gone the next morning. Or have you ever wondered if there is any way that we as citizens can work with our city to maximize the efficiency of recycling? Since I was curious about all of this, I contacted the city’s Department of Public Works and spoke with Kyle Winkler, the city’s recycling supervisor. With his B.S. in Environmental Science and several years of experience in environmental non-profits before his current position, he was able to give me some great insights that I would love to share with you all.

Where Does our Recycling Go and What Happens to It?

That was my first big question, and I learned the city contracts recycling facilities to handle the processing of our commodities. Within Pittsburgh proper, Recycle Source in Hazelwood handles our recyclables, but other municipalities may contract other facilities in the area, including the MRF on Neville Island. These facilities then use a variety of methods to process and sort all of our leftover stuff like shampoo bottles, peanut butter jars, etc.

As a big picture, commodities are mainly sorted using mechanical processes, with some human quality-control mixed in. First things first, though, and that means breaking open those blue plastic bags many of us pack our materials into with a “bag breaker” and creating burden depths of materials on the conveyor belts that will ultimately carry materials into the proper machinery. This is an important step as dried, separated materials can only be stacked so high on a conveyor belt before sorting, but too little material ultimately isn’t efficient.

Next comes the mechanical separation of materials from the conveyor belts. The easiest way to grasp the whole process is to see it, like in this video from Boulder County, Colorado. As a broad summary, though, items are first screened for fiber, cardboard, or mixed paper products. As the processing continues, all glass is broken down on a glass breaker, and magnets begin pulling out metals. Aluminum (i.e., soda cans) is sorted out using reverse Eddy currents. Towards the end of the process, optical sorters separate plastics based on their color and density, and back on the fiber side, paper is sorted and baled based on color.

After the materials have been sorted, they can be sent to various manufacturers and industries that will make use of the various commodities. Here in Pittsburgh, this includes steel mills, paper mills, and other downstream sorters who might need to process commodities further. Glass, for example, goes on to another facility that further sorts the glass by color.

How Can We as Citizens Make the Job Easier for the City?

One of the things I learned during my conversation with Winkler is that Pittsburgh, like many other cities, can’t actually recycle the blue plastic bags that many of us sort our trash into.

“The city can’t go to containerized recycling right now, but it’s helpful for items to go into the trucks loose to expedite sorting,” Winkler says. It avoids the issue of having to clear plastic bags from machinery, reduces the risk of commodity contamination, and it saves all of that plastic going to waste. What does that mean for us? Buy a large blue bin rather than using bags. With items loose in the bin, collection crews can quickly pick up our recyclables, and processing crews can quickly sort materials where they need to be. Many grocery stores can recycle (well, technically down-cycle) our plastics bags, so look into those for when you forget your reusable bags (hate when I do that!)

We also can be more efficient recyclers by checking in with city’s website to see what can and cannot be recycled. Odd items (e.g. clothing or electronics) that make it into recycling bins slow down processing because they cannot be managed at this kind of facility. Winkler also added to avoid any food-related paper products. “Not paper plates, not napkins, not paper towels, paper cups—any of that.” And who wants our nasty pizza grease anyway?

The last of the super simple things we can do: breaking down and bundling our cardboard, following the city’s directions for packing materials for the curb, and separating recyclable from non. Really, anything to help the collection crews quickly spot and collect our recyclable materials helps the city get the job done quickly and efficiently.

Reduce, Reuse, Recycle

But what’s the one thing Winkler doesn’t want us to forget? “There are two other R’s ahead of recycling, and all the work and magic that goes into it. Reduction is so much more important. If we can avoid our consumption and disposal process, we can avoid using all the energy for the trucks, and machinery, and people in processing recyclables.”

He also reminds us that there is a reuse option. “When you have those single use containers, can you use them again? Milk jugs, plastic containers. Can you help avoid the production of new stuff by reusing what you have? Can you bring a reusable cup to Starbucks instead of trying figure out a way to recycle their cups?”

Gettin’ It Done!

In spite some of the challenges that tend to plague most cities’ recycling programs (budgeting issues, momentum, etc), Winkler knows his department is on the right track “[I have a] great crew to work with, and we’re helping to improve the system in a good direction environmentally. We have goals that include reducing costs for everyone and becoming a green city like we are aspire to be. And we are achieving those goals.”