What Happens to All That Plastic?
Editor’s Note (11/27/2017): This post was updated with new statistics on plastic waste generation and recycling, as well as new information on methods of reuse.
What would modern life be like without plastic? According to The World Economic Forum, plastic production has exploded over the last half-century, growing from 16.5 million tons in 1964 to 343 million tons in 2014; it is projected to double by 2036. Where does all this plastic go when we’re done with it?
In 2014, Americans discarded about 33.6 million tons of plastic, but only 9.5 percent of it was recycled and 15 percent was combusted to create electricity or heat.
Most of the rest ends up in landfills where it may take up to 500 years to decompose, and potentially leak pollutants into the soil and water. It’s estimated that there are already 165 million tons of plastic debris floating around in the oceans threatening the health and safety of marine life. And an average of 8.8 million more tons enter the oceans each year, including microplastics, tiny particles less than five millimeters long from cosmetics, fabrics or the breakdown of larger plastic pieces, which may be ingested by marine wildlife.
Relatively little of our plastic waste is recycled because there are various types of plastic with different chemical compositions, and recycled plastics can be contaminated by the mixing of types. Plastic waste is also contaminated by materials such as paper and ink. Separating plastics from non-plastics in the recycling process, and different types of plastic from each other, is labor-intensive and so far there has been no easy solution.
Although the Society of Plastic Industries developed seven codes to distinguish types of plastic for recycling, in reality, only two—polyethylene terephthalate (PET, used for synthetic fibers and water bottles) and high density polyethylene (HDPE, used for jugs, bottle caps, water pipes)—are routinely recycled. But in more and more cities like New York and Chicago, low-density polyethylene (LDPE) plastic bags are now being recycled too. And increasingly, the recycling industry’s use of near‐infrared spectroscopy, which can identify the chemical composition of plastics, is improving the efficiency and speed of plastic recycling.
Plastics that can be recycled are first sorted, shredded and rid of impurities like paper. The shreds are then melted and formed into pellets, which can be made into other products.
AERT in Arkansas, and Virginia-based Trex recycle polyethylene into outdoor decking material, fencing, and doors and windows. Coca Cola is increasing the amount of recycled plastic in its plastic bottles to 50 percent.
Plastic is made from petroleum or natural gas in a chemical process that combines smaller molecules into a large chainlike molecule, often with other substances added to give it particular qualities. (Some, like phthalates and bisphenol A, can have harmful health effects.) Plastic production is estimated to use four percent of global oil production—both as the raw material and for energy in the manufacturing process. Because plastics embody energy from fossil fuels (and actually have a higher energy value than coal and wood), leaving so much of it in landfills is not only an environmental hazard, it is a huge waste of a valuable resource that could be used to produce electricity, heat, or fuel.
The Plastics Division of the American Chemical Council asked the Earth Institute’s Earth Engineering Center to explore ways of recovering the energy inherent in non-recycled plastics. The 2011 report, which was updated in 2014, determined that the amount of energy contained in the millions of tons of plastic in U.S. landfills is equivalent to 48 million tons of coal, 180 million barrels of oil, or one trillion cubic feet of natural gas. If all this plastic were converted into liquid fuel, it could produce 5.7 billion gallons of gasoline, enough to power 8.9 million cars per year. And the fact is, there are now technologies that can put all this waste plastic to good use.
The report examined three ways of utilizing non-recycled plastic for energy production: converting plastics directly into liquid fuel, using separated plastics as fuel in special types of power plants, and increasing the amount of garbage burned in waste-to-energy facilities.
Plastics can be converted into crude oil or other types of products through pyrolysis, a high heat process that does not use oxygen. Agilyx, an Oregon-based company, has developed a system that heats polystyrene from foam cups, packaging materials, and Styrofoam to create a styrene monomer, a building block of the plastic industry. The final liquid product can be sold to other refiners to produce oil or to make more polystyrene.
Plastic2Oil in Niagara Falls, NY, uses unwashed, unsorted waste plastic to produce ultra-low sulfur fuels that do not require further refining. The company maintains that its process is “highly green, clean and scalable.”
A number of other companies in the U.S., Africa, Asia and Europe are investing in technology that produces liquid fuel from plastic wastes.
According to the updated Earth Engineering Center report, power plants specially designed to use non-recycled plastics as fuel could theoretically produce 61.9 million MWh of electricity, enough to power 5.7 million homes.
Burning more garbage in waste-to-energy facilities would recover the energy inherent in plastics and reduce greenhouse gas emissions since landfills emit methane (a greenhouse gas 20 times more potent than carbon dioxide) as garbage decomposes. Unlike incinerators of the past, modern waste-to-energy facilities produce electricity and heat in boilers designed for complete combustion. The U.S. Environmental Protection Agency has said they produce electricity “with less environmental impact than almost any other source of electricity.”
If the amount of garbage sitting in U.S. landfills in 2011 was burned in waste-to-energy facilities, it could theoretically yield enough electricity to power 13.8 million households and reduce coal use by 100 million tons a year. In 2015, 71 waste-to-energy facilities and four other power plants in the United States burned 29 million tons of garbage, generating nearly 14 billion kilowatt-hours of electricity.
A 2009 United Nations Environmental Programme report on converting plastic waste into a resource described the production of gaseous fuels, using high heat to decompose plastic waste, and solid fuel derived from a mixture of waste plastic, paper, and wood. The materials are first shredded, sorted then made into pellets. A number of companies in Japan are producing both solid and gaseous fuels. The Showa Denko company, headquartered in Tokyo, uses heat gasification to recycle plastic waste into ammonia, used to manufacture many products, and CO2 for carbonization.
Liter of Light, a grassroots movement with partnerships around the world, has found another way to recycle plastic bottles. It helps energy-poor communities convert discarded plastic soda bottles into solar bottle bulbs to illuminate homes and streets. The organization has installed over 350,000 bottle lights in more than 15 countries.
The best solutions for our plastic problem are still to reduce our use of plastics, and to reuse and recycle whenever possible. More policies that ban plastic bag use, require bottle deposits and expand recycling would help. But millions of tons of plastic waste still sit in landfills around the country; technologies that are able to tap this waste as a resource can offer multiple benefits, helping to clean up the environment, lessen our dependence on foreign oil, decrease our use of non-renewable virgin resources, reduce greenhouse gas emissions, and generate energy.