Photo credit: Getty Images/China Photos

We’ve gotten really good at creating stuff: cities, roads, and sewer systems that spread across the entire face of the Earth; industrial manufacturing that lets us produce newer, better, cheaper and more durable versions of things we never needed in the first place. We’ve gotten even better at creating more of ourselves: In the past 100 years, the human population has skyrocketed by about 300%, to 7.4 billion people. Not surprisingly, all of this uptick in creating stuff and people comes with a huge byproduct: garbage.

Every year, the world produces about 1.4 billion tons of garbage, more than the weight of 3,900 Empire State buildings; to date we’ve created over nine billion tons of plastic and about 40% of the food we produce ends up in a landfill. To top things off, our recycling rates are abysmal—less than 35% of American trash makes it to the recycling plant. The first step towards finding a solution to our waste is admitting that we have a problem. And thankfully, researchers around the world are confronting the problem head on and are coming up with new ways that we can reuse and recycle, before the Earth turns into a floating pile of garbage.

Below are some of the new and more interesting investigations that could change the future of waste disposal.

Turning Urine and Bad Breath into Plastic and Nutrients

“Urine and CO2 are converted into useful materials through a bit of a complex process,” explained Mark Blenner assistant professor at Clemson University, in an email to Project Earth. The key to Blenner’s “complex process” is yeast — the same stuff that makes bread rise and ferments sugars into alcohol. But Blenner’s team is working on new, genetically altered strains of yeast (called Yarrowia lipolytica) that require CO2 and nitrogen (from our pee) to grow; and as yarrowia lipolytica grows, it releases a few beneficial substances as byproducts: one strain releases Omega-3 fatty acids, which are highly beneficial nutrients that contribute to healthier hearts, eyes and brains, while a different strain releases polyester polymers, which can be used in a 3-D printer to generate all sorts of plastic items.

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Blenner broke down how this all works:

“We start with a type of yeast that are good at making fatty acids and lipids. Then we introduce new genes to give the yeast some capabilities that they don’t normally have. We borrow genes from algae, bacteria, and plants to make our yeast into omega-3 fatty acid producers or into polyester producer. So how does the human waste come into play? Once we have the engineered yeast, we need to give it carbon, nitrogen, and some vitamins. We get the nitrogen from the urea in urine, and the carbon is obtained from CO2 in the... atmosphere.”

Blenner has high hopes for his work: space travel. On a long space mission, being able to create spare parts or generate nutrients from urine and the air astronauts exhale would be very useful. But Blenner also explained that this sort of recycling could be useful here on Earth. “At some point … we as a society are going to have to grapple with questions about what to do with our waste,” said Blenner, explaining that the project still needs refining before it’s ready to be implemented on Earth. “But there are some important lessons from our work that can have an immediate impact. We showed that urea from urine is a better and cheaper source of nitrogen that could be used currently for industrial biotechnology applications.”

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Turning urine into useful materials like plastic would not only reduce the freshwater, money, and energy involved in sewage disposal, but also reduce the pollution that comes from manufacturing plastics.

And what about the feces? I’m glad you asked.

“We are only investigating urine, but have thought about what do with feces,” said Blenner. “It is possible to convert the feces and other solid waste products into small organics through a process known as anaerobic digestion. This could then be used as carbon for the yeast process.”

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Perhaps in the future instead a toilets and plumbing, we’ll have storage tank where yeast transforms our waste into omega-3 fatty acids for us to eat again. Delicious.

Blenner and his team presented their results on August 22nd at the 254th National Meeting & Exposition of the American Chemical Society (ACS). Watch a video of their Q&A here.

Plant Waste into Carbon Fiber

Each year, the U.S. produces almost 70 million tons of paper and paperboard, which, in addition to requiring a whole lot of trees, also produces a huge amount of waste. Whenever we use plants and trees to make substances like paper or ethanol, we’re left with a leftover product called lignin (lignin is an organic substance the helps the plants keep their shape). According to the International Lignin Institute, between 40–50 million tons of lignin are produced each year. And seeing as how we don’t really have a use for it, all this lignin ends up being burned or clogging up landfills. But now a team of scientists from Washington State University is trying to transform lignin into carbon fiber strong enough to be used in cars or even airplanes.

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An employee operates a paper machine at the American Disposables Inc. factory, 2009 in Ware, Massachusetts. Photo credit: Spencer Platt / Staff

“Lignin is a complex aromatic molecule that is mainly burned to make steam in a biorefinery plant, a relatively inefficient process that doesn’t create a lot of value,” explained Birgitte Ahring, the lead researcher on the project, in an interview with Eureka Alert. “Finding better ways to use leftover lignin is really the driver here. We want to use biorefinery waste to create value. We want to use a low-value product to create a high-value product, which will make biorefineries sustainable.”

Ahring’s team is experimenting with mixing lignin with the carbon fiber that is used in modern cars and aircrafts; the goal is to create a more affordable and less resource intensive type of carbon fiber. So far, the team has found that they can create carbon fiber that is 20-30 percent lignin without sacrificing any of the strength. The team is in the process of presenting their new carbon fiber strands to automobile manufacturers, to test their strength in a real world scenario.

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“If we can manage to get a fiber that can be used in the automobile industry, we will be in a good position to make biorefineries more economically viable, so they can sell what they usually would discard or burn,” Ahring said. “And the products would be more sustainable and less expensive.”

Turning Seafood Trash Into Treasure

A mollusc shell pathway in Isle of Mull, Scotland. Photo credit: James Morris

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More and more people across the world are relying on the ocean for their food (in 2013, about 180 million tons of seafood were caught and produced globally). And while this endless seafood buffet is delicious, it also creates an enormous amount of waste: millions of tons of crab, shrimp, lobster, and mollusc shells end up in landfills every year. But researchers from the Royal Belgian Institute of Natural Sciences (RBINS) are trying to change this cycle by repurposing these sea shells.

Shells are composed of over 95% calcium carbonate, a material which is used in a variety of industries, including agriculture and construction. Calcium carbonate is used to improve soil health, treat wastewater, and in the production of cement. But currently, almost all of the world’s calcium carbonate comes from mining and refining marble and limestone. The researchers from RBINS think that with a bit of work, molluc shells could replace marble and limestone as a source of calcium carbonate.

“Mollusc shells are viewed by the aquaculture and seafood industries as ‘nuisance waste’ and largely disposed of in landfills,” explained Dr. James Morris, from the RBINS, in a press release. “Not only is this an expensive and ecologically harmful practice, it is a colossal waste of potentially useful biomaterials.”

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Morris and his team believe that mollusc shells could easily be recycled for industry use (and be worth millions) rather than discarded in landfills. “Reusing shell waste is a perfect example of a circular economy, particularly as shells are a valuable biomaterial,” explained Morris. “Not only does it improve the sustainability of the aquaculture industry moving forwards, but it can also provide secondary economic benefits to shellfish growers and processors as well.”