Recycling 101

Humans have been recycling and reusing products for a very long time. Only recently did the recycling process start to become convoluted and confusing. For instance, did you know that you can recycle the transparent tops of plastic to-go containers (pictured below), but you cannot recycle the black, also plastic bottom? This is a recent change but one that dramatically impacts how we recycle as consumers as well as what happens to our recyclables after we’ve tossed them in the bin.


rec symbol.jpg

It wasn’t until the environmental movement of the 1970s that we actually established a system for recycling. This early system is known as dual-stream and not many people were into it. Dual-stream required that consumers sort their recyclable material by type – paper, plastics, aluminum, etc. What encouraged more people to get into recycling was the switch that took place in the ‘90s. With California heading the way, municipalities all over the country began to adopt single-stream recycling. Rather than having consumers sort their materials, they were now able to put everything into a single bin. When people weren’t presented with the inconvenience of sorting their waste, they were much more apt to participate.

Life of a Recyclable

Putting recyclables into our curbside bins or dropping them off at the various locations across town (Knox county drop-offs here; city drop-offs here) is a very important step in the recycling process.

The goods that we place into these bins are sent to a materials recovery facility, or MRF. When our recyclables arrive at the MRF, they are dumped onto giant conveyor belts where machines and humans alike begin the sorting process.


Sorting the recycled material is essential for the vitality and longevity of recycling as a whole. Our recycled goods are sold, whether that be to other countries for their use/disposal, or to corporations and various other facilities for potential reuse/refurbishment. Certain buyers only want certain materials and this is why sorting is such a top priority. If our goods are not being bought, we can’t do much with them but send them to the landfill.

As a whole, Americans recycle about a quarter of our total waste (as an honorable mention, nearly 9% is also composted!). Unfortunately, we have a bad habit of putting things into our bins that can’t be recycled – 1 in 4 items that we put in the bin aren’t recyclable.

But Why Does this Matter?

Whether we’ve added non-recyclables purposefully or on accident, we risk contaminating the entire batch of recyclables. Especially because MRFs can’t catch every piece of trash that isn’t supposed to be there.

                What is Contamination?

We can contaminate our recyclables a couple different ways.

1.       When we put things into the bin that cannot be recycled. Contaminates slow down the sorting process and can even cause the facility to halt production. The machines at an MRF are designed to handle specific material and foreign objects often do a lot of damage.

2.       By not rinsing out the leftover food bits or commercial waste (think laundry detergent or dish soap) from our recycled goods.

3.       Bagging our recycled goods. Plastic bags and plastic film are among the worst materials to put in our recycling bins. The plastic is too flimsy and thin, causing it to get caught up in the machines. UT Recycling is the only drop-off location in Knoxville that will accept plastic film (bread bags, the plastic around paper towels, grocery bags). Otherwise, you can return plastic bags to many grocery stores – like Kroger!

As I mentioned previously, buyers want specific materials. Whoever is buying our recycled goods will often have a level of contamination they are okay with handling. After our recyclables are sorted at an MRF, they are baled and shipped to the buyer. The buyer will then check for the level of contamination. If the contamination of the bales goes over what the buyer has declared as being reasonable, the buyer can reject the entire shipment. Sometimes MRFs will take the bales and sell them to an alternative buyer. When no one will take the contaminated bale, all of the material is sent to the landfill.  

Local WestRock recyclable material bales

Local WestRock recyclable material bales

Debunking Recycling Tall-Tales

Recycling is important because of environmental and conservation concerns, but it’s also important to note that recycling is valuable economically. In the US, proper recycling generates over half a million jobs and over $100 billion in economic activity. 

This is especially the case in Knoxville! Recycling has the can work for communities. Our local waste management offices and MRF do just that. Recycling also brings in money. As previously noted, recycling changed recently. On a national spectrum, foreign countries were accepting a good portion of our recyclables – China especially. China, however, changed what they were willing to accept and, as a result, the US recycling industry has been facing some issues in dealing with their recycling.

But in Knoxville…

We have an amazing local market that allows us to worry about the foreign recycling business just a little bit less. Our recycled plastic gets sent to Mohawk Carpet in Northern Georgia, our aluminum cans go to Arconic in Alcoa, Gerdau AmeriSteel in Knoxville gets the steel, and cardboard and paper are used to make packaging material at Westrock (our MRF).

Reducing contamination in our recycling is vital in keeping recyclables out of the landfill, but it’s also imperative for keeping our local economy in good shape.

You can find details on what is and is not recycled at the various drop offs here.
City of Knoxville
Knox County
UT Recycling