Sustainability Blog

Press Enter to show all options, press Tab go to next option

Plastics Recycling

OCTOBER 2020: The development and widespread use of plastics over the last 60 years has fundamentally changed the way we live. From food and beverage packaging, medical supplies, sporting equipment, to a never-ending list of consumer goods, plastic is an integral part of our everyday lives. We have become so dependent on plastic it is hard to imagine our world without it.

But with all the convenience and utility that plastic provides, its popularity has led to an environmental challenge. Less than 10% of plastic ever produced has been recycled. Single-use disposable plastics and other rogue plastic items are often littered, migrating to oceans and waterways where they cause disruption to sensitive marine ecosystems, harming and killing marine creatures. Plastic is both a curse and a blessing, and we need to learn how to effectively (and responsibly) manage its use and end of life. 

How is plastic made?
Plastics are largely derived from crude oil, natural gas, and fossil fuels which are refined into monomers like ethylene and propylene, and then into polymers (chains of like molecules linked together). That is why many plastics begin with “poly”, such as polyethylene, polypropylene, and polystyrene. The polymers can be extruded, molded, and cast into a multitude of shapes and applications, and even woven into fibers for textiles. Some plastic is made from non-petroleum sources such as sugar and corn. These “bio-plastics” cannot be recycled the same way and are hard to distinguish from standard petroleum-based plastics in the sorting process and many recycling facilities consider them a contaminant.    

What do those numbers mean?
Ever wonder what the #1-7 means in the middle of the “chasing arrow” recycling symbol on plastic bottles and containers? They are resin identification codes (RIC) that indicate the kind of plastic and are used to help materials recovery facilities sort materials. 

 plastic recycling mobius number guide

Here is a summary:
#1 Polyethylene terephthalate (PET) – typically used in textiles, beverage bottles, and food packaging. Recycled PET resin is used in products like carpeting, clothing, films, and bottles. Easily recycled.
#2 High density polyethylene (HDPE) – used for milk and juice containers, shampoo/toiletry bottles, household cleaning product and medicine bottles. Easily recycled.
#3 Polyvinyl Chloride (PVC) – typically used in toys, blister wrap, medical tubing, construction piping. Difficult to recycle. 
#4 Low Density Polyethylene (LDPE) - mostly used for bags (grocery, dry cleaning, bread, frozen food bags, newspapers, garbage), plastic wraps; coatings for paper milk cartons and hot & cold beverage cups. Difficult to recycle.
#5 Polypropylene (PP) - versatile plastic used for food packaging like yogurt and margarine tubs, reusable microwaveable food ware, and disposable take-out containers. Often recycled by HDPE recyclers, but can be difficult to recycle.
#6 Polystyrene (PS) – commonly referred to as “Styrofoam”, used for egg cartons, packing peanuts, disposable cups and bowls, packaging. Not recyclable at most facilities.
#7 Other – all other plastics, including bioplastics. Polycarbonate (PC) is the most common plastic in this category. Used for eyeglass lenses, TV’s and electronics, compact discs. Difficult to recycle.

How is plastic recycled?
There are a few ways to recycle and manage plastic waste. With mechanical recycling, plastic of like resin codes are first washed, then shredded or ground into small flakes, removing the impurities, and then finally melted and extruded into pellets that are used to make other plastic products. Plastic pyrolysis uses heat to convert plastic waste into fuels for energy. Chemical recycling converts the polymers back into monomers. There have been great advancements and investment in pyrolysis and chemical recycling in recent years.

Plastic bales 3 (2)Each time plastic is recycled its quality decreases and it can only feasibly be recycled 2-3 times. Virgin materials are often added to improve the integrity of the recycled material. The easiest items to recycle are those made from a single material, such as PET water bottles. The most difficult to recycle are those comprised of multi-layered materials, such as aseptic cartons used for broths and orange juice, and other food and drink packaging.  

Not all plastic is recyclable (or easily recyclable). Drinking straws, plastic utensils, and many other single-use disposable plastic items are often not accepted in curbside recycling programs because of difficulty in recovering the items with sorting machinery.  Scientific research is leading to advancements in technology to address the plastic pollution problem. In 2016, Japanese researchers discovered a plastic-eating bacteria that breaks down the polymers into small enough molecules for the bacteria to absorb.

In 2020, scientists further developed this concept and engineered a super-enzyme, derived from these bacteria, that degrades plastic six times faster than the previous version. This discovery, along with advancements in optical sorting equipment, is helping to improve the recycling of plastics.         

Recycling Markets
Which plastics are recycled largely depends on market demand, oil prices, and government regulations. When oil prices are low, it is often cheaper to make plastic from virgin material than recycled plastic material, so the demand for recovered plastic decreases unless government regulations are put in place to require products to contain a certain amount of recycled content. California’s AB 793 does just that. Starting in 2022, plastic bottles subject to CRV (CA Redemption Value) must contain at least 15% recycled plastic, rising to 50% by 2030. 

Number 1 and 2 plastic (PET and HDPE) are the most commonly recycled plastics due to demand for these resins in domestic markets. California’s CRV bottle bill program has played an important role in PET and HDPE recycling in the U.S. by providing an incentive for consumers to sort and return these items. 
Unfortunately, plastics #3 through 5 do not draw the same demand, and since China changed its policy on accepting recyclable material two years ago (its National Sword policy), it has become increasingly difficult to find markets for these materials with U.S. material recovery facilities now turning to other countries such as Vietnam and Bangladesh for markets. 

The City’s franchise waste haulers (Waste Management and EJ Harrison) use state-of-the-art material recovery facilities to sort our plastics and other materials and are able to process and recycle plastics #s 1 – 5.

Number 6 plastic, or polystyrene, is the most problematic of the plastics and cannot be recycled at most facilities, including our local ones. On October 13, City Council took action to restrict the use of this material in the City. More on that to come.

What Can You Do?
Residents are encouraged to try and reduce plastic use as much as possible, replacing plastic items with comparable metal or glass counterparts that are durable, washable, and reusable. However, we realize that plastic is a part of so many things. When you do use it, please be responsible with it and manage it properly.
Both waste haulers recommend and encourage consumers to place plastics #1-5 in a recycling bin. If you don’t place these materials in the recycle bin, they never have a chance of finding a market. 

Not sure if the plastic item you have is recyclable? Try using the City’s RecycleTO “What Goes Where?” app to find out what is recyclable, what is not, and how to properly dispose of your waste. The app is available for download from the Apple Store and Google Play, or use it online at Thanks for doing your part.

Return to full list >>