recycle

Plastic Eating Fungus | Earth Wise

May 26, 2023 By EarthWise Leave a Comment

More than five billion tons of plastic have accumulated on land and sea including the most remote regions of the planet as well as in the bodies of animals and humans. There is a compelling need to recycle as much plastic as possible but doing so is a major challenge. Plastic comes in many varieties and breaking it down for reuse requires different methods for each.

Polypropylene is one of the biggest challenges for recycling. It is a very common plastic used for all sorts of products including food containers, coat hangers, plastic wrap, toys, and much more. It accounts for roughly 28% of the world’s plastic waste, but only 1% of it is recycled.

Polypropylene is seldom recycled because it generally has a short life as a packaging material, and it often becomes contaminated by other materials and plastics. Thus, it generally ends up in landfills.

Researchers at the University of Sydney in Australia have discovered that two common strains of fungi were able to successfully biodegrade polypropylene. The fungi species – with unavoidable Latin names of Aspergillus terreus and Engyodontium album – are typically found in soil and plants.

The researchers found that the fungi were able to break down polypropylene after it had been pre-treated with either UV light or heat, by 21% over 30 days, and by 25-27% over 90 days. This seems rather slow but compared with the nearly endless life of polypropylene in landfills, it is a major improvement.

The hope is that methods like this could ultimately reduce the amount of plastic polluting the environment by encouraging plastic to biodegrade naturally under the appropriate conditions.

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Fungi makes meal of hard to recycle plastic

Photo, posted March 5, 2010, courtesy of Kevin Krejci via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Better Way To Recycle Plastics | Earth Wise

November 10, 2022 By EarthWise Leave a Comment

The global accumulation of plastic waste is an ever-growing problem. At least five billion tons of the stuff has accumulated on land and sea and is even showing up in the bodies of animals and humans. Recycling plastic instead of making even more of it seems like an essential thing to do but it has proven to be extremely challenging.

The main problem is that plastics come in many different varieties and the ways of breaking them down into a form that can be reused are very specific to each type of plastic. Sorting plastic waste by plastic type is extremely impractical at large scale. Certainly, most consumers can’t do it themselves. As a result, most plastic gathered in recycling programs ends up in landfills.

New research at MIT has developed a chemical process using a catalyst based on cobalt that is very effective at breaking down a variety of plastics, including polyethylene and polypropylene, which are the two most widely produced plastics. The MIT process breaks plastics down into propane. Propane can be used as a fuel or as a feedstock for making many different products, including new plastics.

Plastics are hard to recycle because their long-chain molecules are very stable and difficult to break apart. Most chemical methods for breaking their chemical bonds produce a random mix of different molecules which would somehow have to be sorted out in order to be useful for anything.

The new process uses a catalyst called a zeolite that contains cobalt nanoparticles. The catalyst selectively breaks down various plastic polymer molecules and turns more than 80% of them into propane.

The researchers are still studying the economics and logistics of the method, but it looks quite promising.

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New process could enable more efficient plastics recycling

Photo, posted April 25, 2016, courtesy of NOAA Coral Reef Ecosystem Program via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Getting Rid Of Single-Use Plastics | Earth Wise

April 15, 2022 By EarthWise Leave a Comment

Single-use plastics are used only once before they are recycled – or more likely – simply thrown away. These are things like plastic bags, straws, coffee stirrers, soda and water bottles, and most food packaging. They are primarily made from fossil fuel-based chemicals.

Since the 1950s, over 9 billion tons of plastics have been produced, and half of that has been in the past 15 years. There are uses for plastic that are not only reasonable, but are even important, such as for surgical gloves. But for the most part, single-use plastic is the poster child of our throwaway culture that is bad for the environment, for wildlife, and even for human health.

Many cities, states, and even countries are moving toward greatly limiting or outright banning single-use plastics. A recent global survey indicates that the great majority of people around the world are with the program.

According to a 28-country survey from marketing firm Ipsos and the activist group Plastic Free July, three out of four people around the world agree with a ban on single-use plastics. The poll of more than 20,000 people showed that in Latin America, China, and India, more than 80% agree that a ban should happen as soon as possible. Unfortunately, Canada, the United States, and Japan were the least supportive countries. In particular, only 40% of Japanese respondents favored a ban.

Ninety percent of respondents globally support an international treaty to combat plastic pollution and eighty percent said they personally want to buy products with as little plastic packaging as possible. Unfortunately, people in wealthy countries, which produce the most plastic waste, are less likely to support a ban. Those countries typically export their waste to the developing world.

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Three in Four People Worldwide Support a Ban on Single-Use Plastics

Photo, posted April 13, 2006, courtesy of Leonard J Matthews via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Paving With Plastic | Earth Wise

March 25, 2021 By EarthWise Leave a Comment

The country of Ghana has an ambitious plan to recycle and reuse as much plastic waste as it produces each year (which is over a million tons) by 2030. As part of this plan, they have started to pave roads in Accra, the capital city, with asphalt containing a slurry of used plastics – shredded and melted bags, bottles, and snack wraps. Only a quarter of Ghana’s roads are currently paved, so waste plastic has many opportunities for use in paving.

Plastic roads first appeared in India two decades ago. There are now over 60,000 miles of them in that country. Several countries have only recently built their first plastic roads including South Africa, Vietnam, Mexico, the Philippines, and the United States.

Studies have shown that roads containing waste plastic have the potential to perform as well or better than traditional roads. They can last longer, can tolerate wide temperature swings better, are stronger and more durable, and are more resistant to water damage, cracking, and potholes.

Ordinarily, asphalt for roads consists of 90 to 95% aggregate – typically some mixture of gravel, sand, and limestone – and 5 to 10% bitumen, which is a black gooey substance extracted from crude oil that binds the aggregate together. Plastic-enhanced roads replace varying amounts of the bitumen (often as little as 4-10%, but sometimes much more), with plastic that is actually a stronger binding agent.

Plastic roads reduce the amount of bitumen in roads, thereby reducing carbon emissions. The plastics are not heated enough to release gases and the roads do not appear to shed microplastics. Plastic roads will not solve the world’s plastic waste problem, but they can help by diverting lots of plastic from landfills.

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How Paving with Plastic Could Make a Dent in the Global Waste Problem

Photo, posted June 4, 2010, courtesy of Sustainable Initiatives Fund Trust via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Second Life For Electric Car Batteries | Earth Wise

June 17, 2020 By EarthWise Leave a Comment

The number of electric cars around the world is growing steadily. Battery technology continues to improve and the battery packs in the cars can have a long life. Generally, the batteries are considered to require replacement only when their range has dropped below 80% of its original value. Many are warranted to last for 8 to 10 years or more than 100,000 miles. Some seem to do much better than that.

But however long it takes, there will eventually be a wave of used batteries whose performance is no longer deemed sufficient for vehicle use. A new study, published in the journal Applied Energy, looked at the application of used vehicle batteries as backup storage for grid-scale solar photovoltaic installations where they could perform for more than a decade in this less demanding role.

The study looked at the economics of several scenarios including running a solar farm with no battery back up, running the same farm with brand-new batteries, and running the farm with a battery array made of repurposed vehicle batteries.

They found that the used EV battery array, if managed properly, could be a good, profitable investment provided that the batteries cost less than 60% of their original price. They looked at the technical issues of screening batteries and combining batteries from different cars to work together. They also looked at the economics of removing batteries from cars, collecting them, checking them over, and repackaging them.

Overall, they found that reusing vehicle batteries could ultimately meet half the forecasted demand for renewable energy backup storage over the next 10 years and would be both a technical and an economic success story.

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Solar energy farms could offer second life for electric vehicle batteries

Photo, posted June 10, 2011, courtesy of Nick Ares via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Keep Track Of Your LEGOs | Earth Wise

April 9, 2020 By EarthWise Leave a Comment

Plastics in the ocean are a global problem that has attracted a great deal of attention. Most of the concern surrounds grocery bags, bottles, six-pack rings, and similar items. Recent research looked at another source of plastic pollution: LEGOs.

According to environmental scientists at the University of Plymouth in the United Kingdom, it can take more than a thousand years for LEGO bricks to break down in the ocean. The iconic toys are made from a strong plastic called acrylonitrile butadiene styrene or ABS. Pieces of LEGOs are commonly found in ocean trash hotspots and wash up on shores across the globe by the thousands.

LEGOs are one of the most popular children’s toys in history and part of what makes them so popular is their durability. Barefooted parents stepping on one on the floor in a dark room can attest to that fact. But the full extent of their durability came as a surprise to the researchers.

The scientists analyzed pieces of weathered LEGOs collected from beaches, confirmed their age, and compared them to unweathered LEGOs from the 70’s and 80’s. They were able to determine the extent to which LEGOs had been worn down by ocean waves, sand, and salt over time. And it was surprisingly little.

LEGO has acknowledged the environmental impact of its products and has launched a goal to make its bricks from more sustainable sources such as sugarcane-based polyethylene by 2030, as well as improve its efforts to recycle and reuse old LEGO plastic.

Meanwhile, we should all we careful of where our old LEGOs end up.

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