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Repurposing used tires

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Every year, millions of tires from cars and trucks end up in landfills.  Just in the U.S., more than 270 million tires were scrapped in 2021 and more than 50 million of them ended up in landfills.  Discarded tires take up huge amounts of space but, more importantly, create environmental hazards.  They leach chemicals into the environment and are a serious fire hazard.

Some tires are chemically recycled via pyrolysis, which is a high-temperature process to decompose the materials in the tire.  But that process introduces harmful byproducts like benzene and dioxins. 

Researchers at the University of North Carolina Chapel Hill have introduced a new chemical method for breaking down rubber waste.  The process transforms discarded rubber into valuable precursors for epoxy resins.

Rubber – either natural rubber or the synthetic kind used in tires – is made of polymers cross-linked together to form a tough, flexible, and durable material.  These very desirable properties make it difficult to break down rubber.

The new research has led to a two-step chemical process that breaks down the rubber into functional materials that be used to produce epoxy resins.  The method does not require extremely high temperatures, uses aqueous media, and takes only six hours.   It represents an efficient, scalable solution for repurposing rubber waste which, even as many other aspects of motor vehicle are changing for the better, remains a continuing environmental problem associated with driving.

This new research marks a significant step towards greener recycling technologies.

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A Cleaner Future for Tires: Scientists Pioneer Chemical Process to Repurpose Rubber Waste

Photo, posted May 5, 2011, courtesy of TireZoo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A new way to recycle plastic

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Researchers at Northwestern University have developed a new method for recycling plastic that is safer, cleaner, cheaper, and more sustainable than those currently in use.  The U.S. is the world’s largest plastic polluter per capita, and we only recycle 5% of our plastics.  There is a pressing need for better technologies for processing different types of plastic waste.

The Northwestern method is designed to break down polyethylene terephthalate or PET, which is the most common type of polyester plastic.  PET plastic is used in food packaging and beverage bottles and represents 12% of total plastics used globally.  It does not break down easily and is therefore a major contributor to plastic pollution.  It mostly either ends up in landfills or, over time, degrades into tiny microplastics or nanoplastics that end up almost everywhere. 

The non-toxic, environmentally friendly, solvent-free Northwestern process first uses an inexpensive molybdenum catalyst to break apart the bonds in PET.  Then the broken plastic is exposed to ambient air.  Just from the trace amounts of moisture in air, the broken-down PET is converted into monomers, which are the building blocks of plastic.  The monomers could then be recycled back into PET products or used to make other valuable materials.

The process is fast and effective and takes just a few hours.  The catalyst is durable and recyclable, meaning it can be used over and over again.  It only works on polyesters, which means it can be used for recycling mixed plastics without sorting them since it will select only the PET from its inputs.

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Plastic recycling gets a breath of fresh air

Photo, posted August 10, 2013, courtesy of Lisa Risager via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rising methane emissions

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Methane is a colorless and odorless gas that occurs abundantly in nature and is also a product of certain human activities.  It’s a short-lived but highly potent greenhouse gas and, as a result, is a major driver of climate change.  In fact, methane heats the atmosphere nearly 90 times faster than carbon dioxide over a 20-year period. 

Despite a global pledge from more than 150 nations to reduce methane emissions by 30% this decade, methane emissions continue to rise.  In fact, according to a new paper led by researchers from Stanford University, total annual methane emissions have increased 20% over the past two decades. 

The paper, which was recently published in the journal Environmental Research Letters, found that atmospheric concentrations of methane today are more than 2.6 times higher than in pre-industrial times.  In fact, atmospheric methane concentrations are currently the highest they’ve been in at least 800,000 years.

Methane emissions from coal mining, oil and gas production and use, cattle and sheep ranching, and decomposing organic waste in landfills are responsible for driving the growth.  In 2020, the most recent year for which data was available, nearly 400 million tons – or about two-thirds – of global methane emissions came directly from human activities. 

Methane concentrations in Earth’s atmosphere have increased at record speed over the past five years.  According to the research team, only the European Union and possibly Australia seem to have decreased methane emissions from human activities over the past two decades.  This trend “cannot continue if we are to maintain a habitable climate.”

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Methane emissions are rising faster than ever

Photo, posted December 4, 2010, courtesy of Dani Mettler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The carbon cost of wind farms

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Opponents of electric vehicles and renewable energy often try to make arguments to the effect that the carbon footprint associated with producing electric cars, solar panels, and wind turbines negates their advantages over legacy technologies that involve burning fossil fuels.  These arguments have been soundly refuted for the case of electric vehicles but there have been fewer studies related to other green technologies.

A new peer-reviewed study by engineers at the Te Herenga Waka Victoria University in Wellington, New Zealand, has analyzed the carbon emissions associated with wind farm operation.

The main result is that after operating for less than two years, a wind farm can offset the carbon emissions generated across its entire 30-year lifespan.   The study takes into account everything from the manufacturing of individual turbine parts, to transporting them and installing them into place, to decommissioning the entire wind farm at its life’s end.  The environmental impacts of the installation and transportation phases are important, accounting for about 10% of the overall emissions.

The decommissioning phase is also important.  The study recommended the development of a recycling process for end-of-life turbine blades.  Currently, such blades are disposed of in landfills, but a recycling process could reduce emissions.

The manufacturing of wind turbines is the primary contributor to the carbon and energy consumption footprints and continues to be the subject of efforts to be improved.

There are other aspects of wind farms that are subject to criticism including physical impacts on the local environment and various social, wildlife and economic impacts.  But with respect to carbon emissions, wind farms are a winning strategy.

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Wind Farms can Offset Their Emissions Within Two Years, New Study Shows

Photo, posted April 2, 2017, courtesy of Ian Dick via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plastic food packaging

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Reducing the use of plastic is an important environmental goal.  Plastic is made from fossil fuels and plastic pollutes the land and the oceans.  It is estimated that 40% of plastic waste comes from packaging.  Plastic packaging is extremely common in the supermarket and there is a growing desire to reduce its use.  But it isn’t that easy.

Plastic packaging works well to slow the decay of vegetables and fruit.  Its use results in less produce being tossed into the garbage, where it creates almost 60% of landfill methane emissions.  In fact, food is the most common material in landfills.  The average American family of four spends $1,500 a year on food that ends up uneaten and nearly half of all household food waste is fruits and vegetables.

Products like bagged salads, berries in plastic clamshells, and plastic sealed potatoes and cucumbers are popular with shoppers because they stay fresh longer.  They are popular with grocers because the items don’t have to be weighed.  But all these things result in plastic waste.  It is a tradeoff that is difficult to make between food quality and safety vs. the environmental harm caused by plastic.

There are a variety of alternatives to plastic packaging of food that are being explored.  They range from biodegradable, organic coatings that can take the place of plastic films, to cardboard and paper produce packaging. 

But practically, there is yet no affordable and biodegradable plastic alternative that keeps fruits and vegetables safe and fresh.  Solving the food packaging problem is not easy.

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So Much Produce Comes in Plastic. Is There a Better Way?

Photo, posted July 1, 2007, courtesy of Brian via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Red mud and steel

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Most of us have never heard of red mud.  Otherwise known as bauxite residue, it is an industrial waste product generated by the most common process by which aluminum is made and the world produces 200 million tons of red mud each year.  The stuff is a significant environmental hazard being extremely alkaline and corrosive. Most of it ends up in large landfills and the costs associated with disposing of red mud are substantial.

Red mud is red because it contains large amounts of iron oxide, often as much as 60% of it.  Scientists at the Max-Planck Institute in Germany have developed a method for producing steel from red mud that is much less carbon intensive than traditional steel production and that is economically viable.

The scientists melt the red mud in an electric furnace powered in part by green hydrogen.  Running the furnace this way, even when using electricity from only partially renewable sources, results in far fewer greenhouse gas emissions as well as economic benefits.  In the furnace, liquid iron separates from the other liquid oxides and can be extracted easily.  The resultant iron is so pure that it can processed directly into steel.  The remaining metal oxides are no longer corrosive, and they solidify into a glass-like material that can have practical uses in construction.

There are 4 billion tons of red mud that have accumulated worldwide to date.  According to the researchers, their process could produce over 700 million tons of green steel from it, potentially saving 1.6 billion tons of carbon dioxide emissions. 

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Green steel from toxic red mud

Photo, posted September 7, 2021, courtesy of Healthy Gulf via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Ending plastic separation anxiety

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Petroleum-based plastics are one of the biggest environmental problems we face.  They mostly end up in landfills – or worse, in the oceans and elsewhere in the environment – and they basically don’t decompose over time.  Bio-based plastics were invented to help solve the plastic waste crisis.  These materials do break down in the environment providing a potential solution to the problem.  But it turns out that they can actually make plastic waste management even more challenging.

The problem is that bioplastics look and feel so similar to conventional plastics that they get mixed in with the petroleum-based plastics rather than ending up in composters, where they can break down as designed.

Mixtures of conventional and bioplastics end up in recycling streams where they get shredded and melted down, resulting in materials that are of very poor quality for making functional products.  The only solution is to try to separate the different plastics at recycling facilities, which is difficult and expensive to do.

Scientists at Lawrence Berkeley National Laboratory, the Joint BioEnergy Institute, and the incubator company X have invented a simple “one pot” process to break down mixtures of different types of plastic using naturally derived salt solutions and specialized microbes and then produce a new type of biodegradable polymer that can be made into fresh commodity products.

The team is experimenting with various catalysts to find the optimum way to break down polymers at the lowest cost and are modeling how their processes can work at the large scales of real-world recycling facilities. Chemical recycling of plastics is a hot topic but has been difficult to make happen economically at the commercial scale.

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Putting an End to Plastic Separation Anxiety

Photo, posted November 28, 2016, courtesy of Leonard J Matthews via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Brownfields and solar power

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Brownfields are blighted lands that have suffered environmental contamination, making it very difficult to redevelop them or make good use of them.  Generally, they are previously used lands that have the presence or at least the potential presence of hazardous substances, pollutants, or other contaminants at levels exceeding health-based or environmental standards.  There are nearly half a million brownfields in the U.S. that are ripe for repurposing.

One very attractive use for brownfields is to convert them to “brightfields,” which is the colloquial term for brownfields redeveloped into solar projects.  Estimates are that nearly 200,000 U.S. brownfield sites are eligible for brightfield conversion, which could provide hundreds of gigawatts of energy production.  Over 10,000 of these sites are inactive landfills, which alone could power 8 million homes.  Many of these sites have sat unused for decades.

A recent success story took place in Old Bridge Township, New Jersey where an abandoned waste site – designated a Superfund site by the EPA for decades – has now become a solar project that will generate more than $1.2 million a year for the township and will provide reduced-cost electricity for 400 homes, half of which are low- and moderate-income residents.

The site was on the EPA list of Superfund National Priorities , meaning it was considered one of the most serious abandoned hazardous waste sites.  Such sites required continuous monitoring, modifications, and cleanup. 

Projects like the Old Bridge solar project are likely to become increasingly common in the future, as legacy liabilities can be turned into valuable assets.

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How solar installations give new life to blighted brownfields

Photo, posted November 11, 2015, courtesy of Martin Malec via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plastics In The Air | Earth Wise

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Plastic pollution is a big deal.  There are plastics clogging up landfills and waterways and accumulating in the oceans, choking turtles and seabirds.  Annual production of plastics has grown from 2 million tons a year in 1950 to more than 450 million tons today.

As if plastic problems weren’t already big enough, it is becoming increasingly clear that there are growing amounts of microplastic particles in the air. Bits of plastic are lofted into the sky from seafoam bubbles and from spinning tires on highways.  The particles are so light that they can travel for thousands of miles, far from where they originate.

Studies in recent years documented the presence of plastic particles even in places like the Pyrenees in Europe and in federally protected areas of the US.  Other studies have measured the quantity of plastic in the air of various locations and have looked at the origins of the particles.

In the western US, over 80% of microplastics came from roads where vehicles kick up particles from tires and brakes.   In remote areas of the Pacific, there is less than a single particle of plastic per cubic meter of air.  In cities like London and Beijing, on the other hand, there can be several thousand particles per cubic meter.

Microplastics can act as airborne aerosols, like dust, salt, soot, volcanic ash, and other particles.  Aerosols play an important role in the formation of clouds and in temperature regulation on the earth.  At low concentrations, such as exist in most places, microplastic aerosols don’t have much of an effect.  But there are more in the atmosphere all the time and, at this point, scientists don’t really know what effect they will have.

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Microplastics Are Filling the Skies. Will They Affect the Climate?

Photo, posted August 28, 2014, courtesy of Alan Levine via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Recycling Solar Panels | Earth Wise

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Solar panels generally have a useful life of around 20 to 25 years.  The great majority of deployed panels have been installed fairly recently, so they have a long way to go.  But the growth in solar technology dates back to the 1990s, so there are growing number of panels that have already or are shortly coming to their end-of-life.

Today, roughly 90% of solar panels that have lost their efficiency due to age, or that are defective, end up in landfills because recycling them is too expensive.  Nevertheless, solar panels contain valuable materials, including silver, copper, and crystalline silicon, as well as lower-value aluminum and glass. 

The rapid growth of solar technology means that in the coming years, large numbers of retired solar panels will enter the waste stream.  The area covered by solar panels that are due to be retired by 2030 in the U.S. alone would cover about 3,000 football fields.  Clearly, more cost-effective recycling methods are sorely needed.

Engineers at the University of New South Wales in Sydney Australia have developed a new, more effective way of recycling solar panels that can recover silver at high efficiency.  The panel frames and glass are removed leaving just the solar cells themselves.  The cells are then crushed and sieved in a vibration container that effectively separates 99% of the materials contained in them.

Silver is the most valuable material contained in solar cells.  The Australian researchers estimate that between 5 and 10 thousand tons of silver could potentially be recycled from retired solar panels by the year 2050.  But even the other materials contained in solar panels are well worth recovering if it can be done cost-effectively.

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New environmentally friendly solar panel recycling process helps recover valuable silver

Photo, posted November 22, 2008, courtesy of Oregon Department of Transportation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Upcycling Plastic Waste | Earth Wise

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People have generated 8 billion tons of plastic waste over time and less than 10% of it has been recycled.  Millions of tons of it escapes into the oceans.  Plastic piles up virtually everywhere on earth.

There are many approaches to dealing with the plastic waste problem and no one of them is a magic bullet.  Engineers at Stanford University have investigated the prospects for upcycling plastic waste for use in infrastructure like buildings and roads.

They used a mix of computer modeling, scientific research, experimental and field data to analyze the potential for using plastic waste in infrastructure.

Among their findings is that recycled glass fiber reinforced polymer composite – which is a tensile plastic commonly used in car, boat, and plane parts – is a promising material for reuse in buildings. 

Roads in which waste plastic is melted down and mixed with conventional paving materials are becoming more common around the world.  India has installed over 60,000 miles of these roads.  Studies show that roads containing waste plastic have the potential to perform better than conventional roads.  They can last longer, are more durable, can tolerate wide temperature swings, and are more resistant to water damage, cracking, and potholes.  Such roads rely less upon virgin fossil resources, which is obviously advantageous.

Upcycling plastic waste in infrastructure is attracting increasing interest because it creates value from something that is strictly a liability and may end up having regulatory advantages as societies move toward more environmentally friendly and sustainable policies.

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Can we use plastic waste to build roads, buildings, and more?

Photo, posted October 7, 2022, courtesy of the Grand Canyon National Park via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Methane Emissions And The Paris Agreement | Earth Wise

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The Paris Agreement is a legally binding international treaty on climate change adopted at the UN Climate Change Conference in 2015.  Its goal is to strengthen the global response to climate change by committing to limit the rise in global average temperature to well below 2°C above pre-industrial levels, and pursue efforts to limit that increase to just 1.5°C. 

Achieving the goals of the Paris Agreement requires reaching net-zero carbon dioxide emissions by or around 2050, as well as deep reductions in methane and other emissions. 

According to a new study by researchers from Simon Fraser University in Canada, reductions in methane emissions are needed urgently  if we are to meet the goals of the Paris Agreement.  The study, which was recently published in the journal Nature’s Communications Earth & Environment, suggests that global warming levels could be kept below 2°C if methane mitigation efforts are initiated globally before 2030.  However, delaying methane mitigation to the year 2040 or beyond would increase the risk of exceeding 2°C, even if net-zero carbon dioxide emissions were achieved.

Methane is a potent greenhouse gas, second only to carbon dioxide in contributing to global temperature increases over the last two centuries.  However, methane is known to warm the planet 86 times more effectively than carbon dioxide over a 20-year period.

During the past 40 years, more than 60% of global methane emissions have been produced as a result of human activities, such as fossil fuel exploitation, livestock production, and waste from landfills.

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Delaying methane mitigation increases risk of breaching Paris Agreement climate goal, study finds

Photo, posted July 22, 2011, courtesy of Steven W. via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Energy From Fruit Waste | Earth Wise

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In the Back to the Future films, Doc Brown ran his DeLorean time machine on food scraps.  It was a fun bit of science fiction.  But researchers at the University of British Columbia Okanagan in Canada are investigating the potential for using food waste to generate power.

Food waste is not a candidate to replace solar or wind power, but it could be a source of energy for powering fuel cells.  As it is, food waste represents a sustainability challenge because of its detrimental impacts on the economy and the environment.  Organic waste represents a significant fraction of the material in landfills and contributes to methane production, air pollution, and other harmful pollutants.

The UBC researchers focused on fruit waste, which is abundantly available in agricultural regions.  They have devised microbial fuel cells that convert fruit waste into electrical energy using an anaerobic anode compartment.  That is a chamber in which anaerobic microbes – ones that don’t need oxygen – utilize the organic matter to convert it into energy.  The microbes consume the fruit waste and produce water while generating bioelectricity.

It is not like the Back to the Future time machine where you can just toss in scraps of whatever is on hand.  Different types of fruits provide different results when used in the microbial fuel cell. The process works best when the food waste is separated and ground into small particles.  There is a long way to go before the technology could produce bioenergy on a commercial scale, but there is considerable potential for doing something useful with something that is currently worthless.

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UBCO researchers aim to energize fruit waste

Photo, posted July 24, 2011, courtesy of Andrew Girdwood via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Methane And Wildfires | Earth Wise

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Methane is a colorless and odorless gas that occurs abundantly in nature and is also a product of certain human activities.  It’s also a potent greenhouse gas, meaning it affects climate change by contributing to increased warming.  In fact, methane gas is known to warm the planet 86 times more effectively than carbon dioxide over a 20-year period.

According to the U.S. EPA, up to 65% of total methane emissions around the world come from the following human activities: raising livestock, leaks from natural gas systems, and waste from landfills. 

Scientists from the University of California, Riverside have discovered that wildfires are releasing a massive amount of methane gas into the atmosphere.  According to the research team, this source of methane is not currently being tracked by air quality managers in California.  And this omission could have significant implications for climate change mitigation efforts in the state. 

Methane from wildfires is nothing new.  But what is new is just how much of the stuff is being emitted.  According to the findings, which were recently detailed in the journal Atmospheric Chemistry and Physics, the amount of methane from the top 20 fires in 2020 was more than seven times greater than the average from wildfires in the previous 19 years.  Wildfires were the third largest source of methane emissions in California in 2020. 

In 2016, California passed a law requiring a 40% reduction in air pollutants contributing to global warming by 2030.  But as wildfires continue to get bigger and more intense, achieving those reduction targets will get increasingly difficult.

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Methane from megafires: more spew than we knew

Detecting Methane

Photo, posted November 30, 2015, courtesy of Daria Devyatkina via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plastic Eating Fungus | Earth Wise

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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

Getting Rid Of Hydrogen Sulfide | Earth Wise

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Hydrogen sulfide gas produces the characteristic smell of rotten eggs, sewers, stockyards, and landfills.  The petroleum industry produces thousands of tons of the stuff each year as a byproduct of the processes that remove sulfur from petroleum, natural gas, coal, and other products.  The industry faces substantial fines for emitting hydrogen sulfide, but remediation is expensive.

Researchers at Rice University have developed a method for turning hydrogen sulfide into hydrogen gas and sulfur in a single step.  Called plasmonic photocatalysis, it not only gets rid of an undesirable substance, it does so by producing valuable byproducts.

The established way of getting rid of hydrogen sulfide is called the Claus process.  It requires multiple steps, including some that require combustion chambers heated to 1,500 degrees Fahrenheit.  The end product is sulfur and water.

The Rice University process gets all of its energy from light.  A surface of grains of silicon dioxide is dotted with tiny gold nanoparticles.  These particles interact strongly with a specific wavelength of visible light and cause plasmonic reactions that create short-lived, high-energy electrons that drive the catalysis of hydrogen sulfide.  Given that the process requires only visible light and no external heating, it should be relatively straightforward to scale up using solar energy or very efficient LED lamps.

The new hydrogen sulfide remediation technology has been licensed by a Houston-based startup company with more than 60 employees whose founders include some of the Rice researchers.  The process may end up being efficient enough and cheap enough for cleaning up non-industrial sources of hydrogen sulfide such as sewers and animal waste.

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New catalyst can turn smelly hydrogen sulfide into a cash cow

Photo, posted July 8, 2021, courtesy of Doug Letterman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fuel From Coffee Grounds | Earth Wise

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The world drinks a lot of coffee.  Americans alone consume 400 million cups a day.  Each cup of coffee results in about half an ounce of coffee grounds.  Adding that up, this country produces over 6,000 tons of coffee grounds each day.  While coffee grounds are not particularly harmful, that is an awful lot of waste that mostly ends up in landfills or is incinerated.

Researchers at Aston University in the UK have developed a method of producing high-quality biodiesel fuel from coffee grounds.  Their study was published in the journal Renewable and Sustainable Energy Reviews.

The technique consists of growing a particular species of microalgae (Chlorella vulgaris) directly on spent coffee grounds.  The coffee grounds provide both the nutrients for the microalgae and a structure upon which it can grow.   Exposing the algae to light for 20 hours a day and dark for just four hours a day produced the best quality biodiesel.

Microalgae is well-known as a feedstock for biodiesel production.  Previously, it has been grown on materials like polyurethane foam or nylon which don’t provide any nutrients.   Using the coffee grounds as the substrate for growth means that no external nutrients are needed.

The resultant enhanced biodiesel produces minimal emissions and good engine performance and meets both US and European specifications.  This feedstock for producing biodiesel is ideal since it doesn’t require any competition with food crops and instead makes use of a widely available waste product.  The hope is that it may reduce the cutting down of palm trees to extract oil for biofuel.  In southeast Asia, this has been a major source of deforestation and increased greenhouse gas emissions.

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Aston University researchers ‘feed’ leftover coffee grounds to microalgae to produce low emission biodiesel

Photo, posted October 13, 2007, courtesy of David Joyce via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Turning Plastic Into Protein | Earth Wise

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Our planet is choking on plastic.  According to the United Nations, 79% of the 6.3 billion tons of plastic produced every year accumulates in landfills.  Half of all plastic produced is actually designed to be used just once and thrown away.  But plastic is not only accumulating on land.  In fact, the world’s oceans are projected to contain more plastic by weight than fish by the year 2050.     

According to new research, solving the plastic waste issue could help address another prominent global issue: hunger.  A multidisciplinary team of engineers, chemists, and biologists led by researchers from Michigan Tech University has developed a process to break plastics down to be recycled into useful products, including edible protein powder.

The research team’s process converts plastic into compounds using heat and a reactor that deconstructs the material’s polymer chains. The oil-like substance is then fed to a community of oil-eating bacteria.  The bacteria grow rapidly on the oily diet, producing more bacterial cells composed of roughly 55% protein.  This majority-protein byproduct is then dried out and turned into an edible powder.   The end result doesn’t look like plastic at all.  In fact, it resembles a yeast byproduct that comes from brewing beer. 

This research is funded by an award from the US Department of Defense.  The DoD often deploys soldiers in areas where access to food is challenging.  Converting plastic to protein could be part of a solution to that problem. 

While eating something that began as plastic might take some getting used to, it could be part of the solution to both plastic pollution and global hunger.

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Turning Trash Into Treasure: The Plastic to Protein Powder Solution

Beat Plastic Pollution

Photo, posted February 2, 2022, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Greening Halloween | Earth Wise

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According to the National Retail Federation, Halloween participation is expected to return to pre-pandemic levels this year.  Spending on Halloween festivities by the 69% of Americans who celebrate is expected to add up to $10.6 billion in 2022 – or more than $100 per person – reaching a new record high. 

Halloween generates a mind-boggling amount of waste.  Picture all the flimsy single-use costumes, plastic candy wrappers, mass-produced decorations, and so on.  Here are some tricks to treat you to a greener holiday.

Our first trick is to invest in quality costumes.  Mass-produced (and often single use) costumes leave the largest carbon footprint from Halloween.  They are often made from unsustainable materials, manufactured in countries with poor labor standards, and too many end up in landfills by mid-November. By renting, thrifting, swapping, or making your own costumes, many of the negative impacts of dressing up for the holiday can be avoided.

Our second trick is to invest in environmentally-friendly decorations and supplies.  For example, carve local pumpkins and save the seeds and flesh to eat later.  Make your own spooky decorations.  If you do buy decorations, ensure that they are durable and reusable.  And use a wicker basket, old bag, or pillowcase to trick-or-treat.

Our third trick is to pass out organic and fair trade candy.  Some of the largest candy manufacturers are major drivers of deforestation and species extinction around the globe due to their demand for sugar, palm oil, and cocoa beans.

If you’ve already spent your $100 this year, consider these changes for next year.  It’s never too late to become a superhero.

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Retail Holiday and Seasonal Trends: Halloween

Photo, posted October 14, 2007, courtesy of Brian via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon Storage In Harvested Wood | Earth Wise

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Trees are an exceedingly important carbon sink on our planet.  For this reason, deforestation is a major contributor to climate change.  But when trees are harvested for wood products like lumber, much of the carbon in that wood continues to be stored.  Even when a wood product is discarded at the end of its useful life, it can keep storing carbon.

Over 90% of new single-family homes in the U.S. are built with wood.  Each year, about 400,000 homes, apartment buildings, and other housing units are lost to floods and other natural disasters.  Others fall apart from decay or are torn down to be replaced with newer structures.  Given how much carbon is stored in houses, it is important to understand what the future trajectory of residential structures will be.

A new study by the USDA Forest Service published in the journal PLOS ONE looks at the future of harvested wood products in residential structures.  According to the study, wood products in these structures will continue to increase the country’s carbon storage for the next 50 years. 

Even after residential structures reach the end of their useful life and much of the materials end up in landfills (which is typical in this country), the wood products do not immediately release their carbon.  It may take decades for that to happen.

The study looked at various scenarios for future home construction.  Although housing starts are projected to decline in the future, residential housing and the need to maintain existing structures are projected to continue to increase carbon storage in wood products for the next several decades.

The role of trees as a carbon sink does not end when they are harvested for their wood.

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Carbon Storage in Harvested Wood Products

Photo, posted January 27, 2022, courtesy of Luke McKernan via Flickr.

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