From the Bin to the Curb to the Plant

Mt. Lebanon’s recyclable material goes to Recycle Source in Hazelwood, where it is processed for sale to vendors in the U.S. and overseas. Along with decreasing the amount of trash that is sent to a landfill, recycling can offset the cost of a trash collection contract.

In a time when political and cultural differences are driving wedges everywhere, one unifying thing it’s probably safe to say is that most of us agree it’s a good idea to recycle more and also to reduce the amount of trash we send to the landfills. Maybe not all of us, but most of us. Single-stream recycling was adopted here in 2009, allowing residents to commingle all recyclable plastic, paper and metal items in a single container marked clearly with recycling stickers and placed curbside. 

Although many residents still have questions about how to recycle the right way—which items can and can’t be tossed into the bin and how to prepare things properly—our record is improving. As of October 2017, Mt. Lebanon had recycled 2,059 tons of material, compared with 1,675 tons through the same period in 2016, which represents a 23 percent increase. Mt. Lebanon, like the 21 other communities in the South Hills Area Council of Governments, is in the process of evaluating options for the next joint trash hauling contract, which will take effect in 2019.

Mt. Lebanon’s current contractor is Republic Services, which picks up trash every week and recycling every other week. Among the options under consideration is a switch to weekly recycling pickup. 

From above, a worker separates the  cardboard that can be recycled from the waste that passes by on a conveyor belt.

“Recyclable” is not technically the right word to describe what we place in our curbside bins, as there is a difference between what is recyclable and what is recoverable. Pretty much anything can be recycled, if you have unlimited resources, equipment and money, explains John Hudock, general manager of Recycle Source in Hazelwood, the material recovery facility (MRF) where Mt. Lebanon sends its recyclable material.

“We’re set up to recover,” Hudock says, even though the rest of us may call it “recycle.”

Styrofoam is an example of a recyclable but not recoverable material. Since it’s about 95 percent air, it would take a staggering number of fast-food containers and packing peanuts to fill a truck. Also, like pizza boxes—another prohibited item—the amount of grease and other contaminants styrofoam absorbs requires a much more involved recovery process. That’s why neither item is on the permitted list of recyclables.

It’s important to become familiar with the list of acceptable items, because anything you throw into your recyclable bin—on purpose or by mistake—that is not recoverable poses a potential problem. It might contaminate the load, meaning it cannot be sold, or it could damage the machinery at the plant.

Paying attention to what goes into the recycle bin could in the long run make a difference in the cost of recycling to taxpayers, because the best price for recovered material plays a big role in determining the cost of a waste hauling contract. Even if a material is in high demand—and demand changes frequently, Hudock says—no one wants to purchase contaminated materials.

“Right now, China is paying record prices, but only if the material is the highest quality.” 

China has enacted environmental initiatives—Green Fence in 2013 and National Sword last year—that have tightened the regulations on what they accept from MRFs. Chinese inspectors select random bales in a shipment of recycled material, weigh them, then pull them apart, separate out the contaminated material and weigh it. If the contaminated material is greater than 1.5 percent of the gross weight, or if it contains any prohibited materials at all—such as e-waste, textiles, food waste or medical waste—the inspectors will refuse to accept the shipment, the material stays on the ship and the recycler must search for other markets. Some other countries that are big consumers of recycled material, most notably India, Vietnam and South Korea, have less stringent standards but don’t pay as well.

Republic Services, our current waste hauler, picks up our recyclables and takes them to Recycle Source. There, the truck drives onto a scale, is weighed and then proceeds to the tipping point, where it dislodges its cargo. The initial pre-sort is done manually. One of the first things the crew gets rid of are the plastic grocery bags that so many people erroneously package their recyclables in.

Most MRFs are not equipped to recycle the bags. Their light weight means they can be blown into machinery where they don’t belong and can damage the sensitive recycling equipment. Damage to the equipment can shut down the whole facility for repairs. Other items that can damage the recycling equipment are wire coat hangers and plastic garden hoses that wrap around the screens that separate the material.

“It’s unbelievable the stuff people will try to recycle,” says Hudock. “Car parts, pots and pans, folding chairs. During hunting season, we usually get one or two deer carcasses.”

A Pittsburgh Environmental Services worker backs in to the collection area of Recycle Source to drop off a load of material to be separated and eventually recycled.

Even acceptable materials such as plastic food containers can foul a shipment if they are not clean. Since the material will sometimes sit for weeks or even months before reaching its final destination, food residue can grow mold which will spread throughout the bale of material.

Once the stuff has been tipped and gone through an initial manual sort, a crane grabs a chunk from the pile and drops it onto a conveyor belt, where gapped screens separate out corrugated cardboard and allow smaller items to fall through. Smaller screens lift out the remaining paper and separate it from the plastic, glass and metal bottles and cans. The paper products are then hand-sorted to remove any remaining unacceptable material.

The glass, metal and plastic material goes through a process that allows the heavier glass to fall out and be broken; then magnets will pull out steel cans; and aluminum cans and plastic containers pass through an optical sorter. The sorter is composed of bright light bulbs and camera lenses that record the light waves, or “signatures” of each material, which is then read by a spectrometer.

Material that has been separated and bundled is neatly stacked inside Recycle Source to then be trucked away to be recycled into new products.

If the signature matches a specific type of recoverable material, such as soft drink bottles or detergent jugs, the sorter will then blow out a blast of compressed air that separates the item from the rest of the material. Hudock says that too much liquid left in a plastic container can cause a misread of the material. “The computer is making decisions in milliseconds, and too much liquid can fog the optics.”

The aluminum passes through an eddy current, which is like a reverse magnet, repelling non-magnetic material.

Once the material has been separated, it is fed into a baler and stored on the floor until it is shipped. All of the remaining unusable material is taken to a landfill.

Since switching to single-stream recycling, Mt. Lebanon has reduced the amount of trash it has sent to landfills by 20 percent.

This represents about a week’s worth of recycling from Mt. Lebanon and the other communities Recycle Source serves.

Keeping material out of landfills, especially material that can be recycled, has a number of benefits. Making paper from existing paper means not having to cut down trees. Recycling aluminum means not having to mine more aluminum. Recycling plastic takes less energy and fewer resources than making new plastic.

Also, less material in landfills means less greenhouse gas emissions. Landfills are one of the highest human-produced sources of methane and carbon dioxide.

Finally, being able to make money from recycled material instead of paying money to take it to a landfill helps to keep the cost of trash collection lower.

Photos by John Schisler