Plastics are part of our daily lives and are used in a variety of items, from toys to containers to furniture. In 2011, the U.S. generated 32 million tons of plastic, but only eight percent of that plastic was recycled. Most plastics end up in landfills, where they may take decades or even centuries to decompose and are capable of leaking pollutants into the surrounding soil and water. But plastics in landfills are not just hazardous to the environment. Plastics embody energy from fossil fuels, so leaving them in landfills is a massive waste of a valuable, non-renewable resource that could be used to produce electricity, heat or fuel. The amount of energy contained in the plastic that piles up in U.S. landfills is equivalent to 36.7 million tons of coal, 139 barrels of oil or 783 billion cubic feet of natural gas. Plastic has even made its way into the oceans, where an estimated 100 million tons of plastic debris threaten marine life and the health of our ecosystem.
How Are Plastics Recycled?
Plastics from municipal solid waste are generally collected from curbside recycling bins or drop-off sites. In curbside recycling, residents separate recyclables materials from non-recyclables. A drop-off site collects a variety of materials, which are deposited by type into separate receptacles.
The plastics are then transported to a material recovery facility (MRF), where materials are sorted, and the resulting mixed plastics are sorted by type, baled and sent to a reclaiming facility. At the facility, the plastics are thoroughly inspected for contaminants, then ground down into small flakes and washed. A flotation tank then further separates out the contaminants in the plastics, after which the clean flakes are dried, melted, filtered and formed into small pellets known as “nurdles.” These pellets are sold and shipped to product manufacturing plants, where they can then be made into new plastic products.
What Do the Numbers on Plastic Containers Mean?
On each plastic product, there is a number enclosed in a small triangle. This number relates to the Resin Identification Code (RIC) which the Society of the Plastics Industry (SPI) introduced in 1988. The SPI developed this code to help both recyclers and manufacturers identify the resin contents of plastic bottles and containers in the municipal solid waste stream. Each plastic product is marked with a number between one and seven, which indicates the type of plastic and its resin content. RICs help individuals to sort plastics, ensuring that the recycled product is as pure as possible.
Number 1 is polyethylene terephthalate (PETE or PET), a polymer resin. PET is one of the most frequently recycled plastics and has been widely used to create polyester fibers. PET can be found in carpet, food and liquid packaging, textiles and films. According to the U.S. EPA, the primary market for recycled PET bottles is fiber for carpet and textiles. Recycled PET can also be used in non-food bottles, office binders and folders and fiberfill for ski jackets, outerwear and sleeping bags.
Number 2 refers to high density polyethylene (HDPE), which is made from petroleum. Along with PET, HDPE plastics have the highest recycling rate. HDPE is used in numerous products, including beverage bottles, containers, plastic bags and playground materials. Recycled HDPE is primarily used to produce bottles for motor oil and detergent, but it can also be manufactured into pails, construction fencing, lawn chairs, trash cans and containers for liquid cleaning supplies.
Number 3 is polyvinyl chloride, more commonly known as PVC or vinyl. In addition to its chemical resistance and strength, PVC has stable electrical properties, which is why it is often used in cables and electrical boxes. PVC can also be found in decks, carpet backing, floor tiles, fencing and pipes. Recycled vinyl is used to produce drain pipe, office accessories and trash containers.
Number 4 is low density polyethylene (LDPE), a thermoplastic made from petroleum. Thermoplastics soften when they are exposed to heat and can be reshaped repeatedly. This flexibility makes LDPE perfect for packaging and film-like materials. LDPE is also used in computer components, lids, trays and tubing. LDPE can be recycled and used to make new grocery and trash bags.
Number 5 refers to polypropylene (PP), which is used in a wide variety of applications, including packaging, textiles and automotive components, such as batteries. Recycled polypropylene is used to manufacture new batteries, as well as in other automotive applications and in products such as wheels for barbecue grills and lawn mowers.
Number 6 is polystyrene (PS), which, when heated and exposed to air, forms Styrofoam. Polystyrene can also be found in plastic cutlery, cameras, insulation and thermometers. Recycled polystyrene can be used to produce office and school supplies, protective industrial packaging and plant containers.
Number 7 refers to “other” and includes plastics that do not fall into one of the six primary categories. Some other common types of plastics are better known by their brand names. Polytetrafluoroethylene is more commonly referred to as Teflon, which is used in cookware and waterproof coatings. Polyvinylidine chloride is best known as Saran, which is used to produce the popular plastic wrap for foods.
Most community recycling programs accept only plastic bottles and containers labeled with codes 1 and 2, but those two categories combined represent almost 96 percent of all plastic bottles and containers used in the U.S. Today, hundreds of products are produced or packaged in recycled plastic. Artificial lumber made from recycled plastic is used to make fence posts and park benches. Plastic bags and stretch wrap are recycled into durable decking material. Even something as common as soft drink bottles can be recycled into polyester fiber that can be used to create baseball caps.
Why Recycle Plastic?
Manufacturing, transporting and disposing of municipal solid wastes, like plastic, leads to greenhouse gas emissions, which trap heat in the planet’s atmosphere. These gases are released at every stage of a product’s life cycle, contributing to climate change.
For example, look at the life cycle of a PET plastic bottle. If the bottle is incinerated, it releases carbon dioxide as a by-product, which contributes to the increase in the rate of global warming. If the bottle is landfilled, it will slowly decompose and release methane, a greenhouse gas that is 21 times more potent than carbon dioxide. In addition, materials that are disposed of in landfills have to be replaced by new products manufactured from raw materials, and the extraction of raw materials requires fossil fuel combustion, which releases more carbon dioxide into the atmosphere and reduces a non-renewable resource.
If the PET plastic bottle is recycled, however, it will help to save energy. According to the EPA, the current PET bottle recycling rate results in an energy savings equivalent to that consumed by 165,000 U.S. households each year. Recycling also leads to cleaner air. If the national PET bottle recycling rate increased by just 25 percent, we would avoid the greenhouse gas emissions equivalent to 131 million gallons of gasoline.