Some 15 years ago, when Gregg Beckham started to scuba dive seriously, he slipped into the water off the coast of Thailand, and what he found was a lot of floating plastic bottles and waste. Now he finds plastic refuse wherever he dives.
“You can’t go diving without being inundated with plastics in places that 10 or 15 years ago were quite pristine,” said the 38-year-old researcher at the National Renewable Energy Laboratory in Golden. “Even in the Caymans, which is clean-ish, you still see a lot of plastics.”
In an effort to stanch the flow of plastic waste streaming into the oceans, Beckham has combined his love of diving and his work at NREL’s Bioenergy Science and Technology Department.
Beckham and a team of researchers have developed a technique to recycle one of the most widely manufactured plastics in the world, polyethylene terephthalate or PET, into a more valuable product – a high-strength composite. They hypothesize that their work developing a stronger composite also solves for the ocean pollution problem by appealing to the economic sensibilities of waste pickers in developing nations.
“There is no incentive for anybody to gather plastics and take them to a recycling facility, but if there is an economic incentive, if someone can make money, it’s a winning proposition,” Beckham said.
We can do better than carpets, sweaters and strapping
Your water and soda bottles are made of PET. Ditto for the supermarket strawberry boxes and microwave-safe carry out containers. Composites are used in the bodies of cars and airplanes, as well as in making snowboards.
PET bottles and containers that are recycled are chopped, refined and melted, which turns them into fibers that are used for, among other things, polyester carpets, sweaters and industrial strapping.
Beckham calls this “down-cycling,” because the products eventually end up in the landfill. “In down-cycling, there is very little economic incentive to recycle.”
The idea is to “upcycle” to a more valuable product. Beckham said a pound of reclaimed clear PET fetches about 50 cents while composites sell for $2.50 a pound. “That is significant value added.”
Still the task is enormous. About 320 million tons of all kinds of plastics are produced each year, including 30 million tons of PET. About 8 million tons of plastic end up in the oceans annually, according to the World Economic Forum, and by 2050, if nothing is done, there will be more plastics by weight in the seas than fish.
Between 55% and 60% of plastic waste in the oceans comes from five countries: China, Indonesia, Thailand, Vietnam and the Philippines, according to a 2015 study by the Ocean Conservancy and the McKinsey Center for Business and Environment.
“Plastics that have low value are more likely to leak into the oceans,” the report said, referring to cast off bottles and containers that end up neither in the landfill nor the recycling stream. Much of the collection of plastics in Southeast Asia rests with waste pickers who scavenge garbage dumps and who, the report said, “tend to value their efforts on high-value plastics.”
“When you have people living on less than $5 a day and you can make $6 a day collecting plastics – I call that a win,” Beckham said.
Since the Ocean Conservancy’s report, the problem looks to be spreading to Africa as countries on the continent “move up the development curve,” creating economies with greater demand for consumer products, said Susan Ruffo, the Ocean Conservancy’s director for international initiatives.
In Vietnam, Ruffo said PET is collected by waste pickers. “You can see people chopping it and melting in backyards,” she said. The material ends up in low-value products, such as pallets.
“The way that Gregg is looking at this is exactly right,” Ruffo said. “In a lot of these places, there isn’t any value on these plastics.”
There are initiatives underway to create that added value. In Indonesia, Paris-based Danone has begun a program to recycle the PET water bottles sold by its local AQUA subsidiary back into new water bottles. In Mexico, the Coca-Cola affiliate is producing 100% recycled PET bottles for its Ciel brand of bottled water.
Looking for more value in all that trash
“There is no one solution to this problem, which is why it is so difficult,” Ruffo said. “We have to come at it in a lot of different ways, which is why it’s good people are thinking about new approaches.”
While recycling plastics may seem a stretch for a laboratory better known for its work on solar and wind technologies, the work fits right in with the Bioenergy Sciences group.
The lab works on taking large volumes of low-value solids – wood chips, wheat stalks and corn stover (the stems, cobs and leaves remaining after harvest) – and turning them into more valuable products such as biofuels.
“The problem is exactly the same conceptually with plastics,” Beckham said. “You’ve got a waste, low-value, diffuse, solid material for which we develop technologies to break them down into higher value.”
The lab also is creating bio-based monomers that could be used as chemical building blocks. Monomers are molecules that can be bonded to other identical molecules to form a polymer. “It was two sides of our brain, and we had this ‘aha!’ moment when we realized we could put them together,” Beckham said.
The challenge chemically was getting PET, which does not easily combine with fiberglass, to make a composite. The researchers used one of their bio-monomers, muconic acid, to aid in the process.
Muconic acid can be derived from sugars or aromatics present in waste plant material. It can also be made from the petroleum waste stream.
The composite the Beckham team created has demonstrated twice the strength and improved adhesion to fiberglass compared to petroleum-derived, fiberglass-reinforced plastic, according to a paper published by the group in the scientific journal, “Joule.”
Despite that success, Beckham’s process probably isn’t going to save the world’s oceans anytime soon. So far, the lab has only produced pieces of the composite big enough to hold in your hand, and the all-important muconic acid is brewed in boutique batches.
Commercialization will take an industrial partner
“You can’t go buy six tons of munconate from BASF or BP,” Beckham said, referring to one of the world’s largest chemical companies and one of the biggest international oil companies. “No company is making it. So that’s one challenge. It is a huge hurdle to economic viability and scalability.”
What will really determine the future of the project is industry partnerships. “That is what we are on the hunt for,” Beckham said. “If industry is interested, we are interested in working with them.”
It is only when an automaker, snowboard manufacturer, wind turbine company or building materials producer comes forward with the precise specifications the PET composite would have to meet that the NREL research will be able to determine if there is a market for their material.
Auto manufacturers are already using a lot of recycled plastic in their vehicles, said Steve Alexander, president of the Association of Plastic Recyclers.
High-density polyethylene and high-density polypropylene composites are used in auto bodies, and recycled PET is in the carpets and interior cloth roof coverings in automobiles.
“It is a very big market, and it is growing like a banshee,” Alexander said. “The key is that the collection infrastructure is woefully inadequate.”
Alexander noted that the combination of a lot of investment in process capacity and the scramble to get adequate supplies has left recyclers operating on “thin margins.”
Still, with only 30% of PET being recycled in the U.S, and even less abroad, Beckham said upcycling can’t help but improve the situation. “The more valuable you make it, the more it will be collected.”
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