Posts Tagged ‘recycling’


The company behind the breakthough, Carbios, has partnered with major companies including Pepsi and L’Oréal. Photograph: Mario Anzuoni/Reuters

A mutant bacterial enzyme that breaks down plastic bottles for recycling in hours has been created by scientists.

The enzyme, originally discovered in a compost heap of leaves, reduced the bottles to chemical building blocks that were then used to make high-quality new bottles. Existing recycling technologies usually produce plastic only good enough for clothing and carpets.

The company behind the breakthrough, Carbios, said it was aiming for industrial-scale recycling within five years. It has partnered with major companies including Pepsi and L’Oréal to accelerate development. Independent experts called the new enzyme a major advance.

Billions of tonnes of plastic waste have polluted the planet, from the Arctic to the deepest ocean trench, and pose a particular risk to sea life. Campaigners say reducing the use of plastic is key, but the company said the strong, lightweight material was very useful and that true recycling was part of the solution.

The new enzyme was revealed in research published on Wednesday in the journal Nature. The work began with the screening of 100,000 micro-organisms for promising candidates, including the leaf compost bug, which was first discovered in 2012.

“It had been completely forgotten, but it turned out to be the best,” said Prof Alain Marty at the Université de Toulouse, France, the chief science officer at Carbios.

The scientists analysed the enzyme and introduced mutations to improve its ability to break down the PET plastic from which drinks bottles are made. They also made it stable at 72C, close to the perfect temperature for fast degradation.

The team used the optimised enzyme to break down a tonne of waste plastic bottles, which were 90% degraded within 10 hours. The scientists then used the material to create new food-grade plastic bottles.

Carbios has a deal with the biotechnology company Novozymes to produce the new enzyme at scale using fungi. It said the cost of the enzyme was just 4% of the cost of virgin plastic made from oil.

Waste bottles also have to be ground up and heated before the enzyme is added, so the recycled PET will be more expensive than virgin plastic. But Martin Stephan, the deputy chief executive at Carbios, said existing lower-quality recycled plastic sells at a premium due to a shortage of supply.

“We are the first company to bring this technology on the market,” said Stephan. “Our goal is to be up and running by 2024, 2025, at large industrial scale.”

He said a reduction in plastic use was one part of solving the waste problem. “But we all know that plastic brings a lot of value to society, in food, medical care, transportation. The problem is plastic waste.” Increasing the collection of plastic waste was key, Stephan said, with about half of all plastic ending up in the environment or in landfill.

Another team of scientists revealed in 2018 that they had accidentally created an enzyme that breaks down plastic drinks bottles. One of the team behind this advance, Prof John McGeehan, the director of the Centre for Enzyme Innovation at the University of Portsmouth, said Carbios was the leading company engineering enzymes to break down PET at large scale and that the new work was a major advance.

“It makes the possibility of true industrial-scale biological recycling of PET a possibility. This is a very large advance in terms of speed, efficiency and heat tolerance,” McGeehan said. “It represents a significant step forward for true circular recycling of PET and has the potential to reduce our reliance on oil, cut carbon emissions and energy use, and incentivise the collection and recycling of waste plastic.”

Scientists are also making progress in finding biological ways to break down other major types of plastic. In March, German researchers revealed a bug that feasts on toxic polyurethane, while earlier work has shown that wax moth larvae – usually bred as fish bait – can eat up polythene bags.

https://www.theguardian.com/environment/2020/apr/08/scientists-create-mutant-enzyme-that-recycles-plastic-bottles-in-hours?CMP=oth_b-aplnews_d-1


Sweden’s waste incineration plants generate 20 percent of Sweden’s district heating.

When it comes to recycling, Sweden is incredibly successful. Just four percent of household waste in Sweden goes into landfills. The rest winds up either recycled or used as fuel in waste-to-energy power plants.

Burning the garbage in the incinerators generates 20 percent of Sweden’s district heating, a system of distributing heat by pumping heated water into pipes through residential and commercial buildings. It also provides electricity for a quarter of a million homes.

According to Swedish Waste Management, Sweden recovers the most energy from each ton of waste in the waste to energy plants, and energy recovery from waste incineration has increased dramatically just over the last few years.

The problem is, Sweden’s waste recycling program is too successful.

Catarina Ostlund, Senior Advisor for the Swedish Environmental Protection Agency said the country is producing much less burnable waste than it needs.

“We have more capacity than the production of waste in Sweden and that is usable for incineration,” Ostlund said.

However, they’ve recently found a solution.

Sweden has recently begun to import about eight hundred thousand tons of trash from the rest of Europe per year to use in its power plants. The majority of the imported waste comes from neighboring Norway because it’s more expensive to burn the trash there and cheaper for the Norwegians to simply export their waste to Sweden.

In the arrangement, Norway pays Sweden to take the waste off their hands and Sweden also gets electricity and heat. But dioxins in the ashes of the waste byproduct are a serious environmental pollutant. Ostlund explained that there are also heavy metals captured within the ash that need to be landfilled. Those ashes are then exported to Norway.

This arrangement works particularly well for Sweden, since in Sweden the energy from the waste is needed for heat. According to Ostlund, when both heat and electricity are used, there’s much higher efficiency for power plants.

“So that’s why we have the world’s best incineration plants concerning energy efficiency. But I would say maybe in the future, this waste will be valued even more so maybe you could sell your waste because there will be a shortage of resources within the world,” Ostlund said.

Ostlund said Sweden hopes that in the future Europe will build its own plants so it can manage to take care of its own waste.

“I hope that we instead will get the waste from Italy or from Romania or Bulgaria or the Baltic countries because they landfill a lot in these countries. They don’t have any incineration plants or recycling plants, so they need to find a solution for their waste,” Ostlund said.

In fact, landfilling remains the principal way of disposal in those countries, but new waste-to-energy initiatives have been introduced in Italy, Romania, Bulgaria, and Lithuania.

It is also important, Ostlund notes, for Sweden to find ways to reduce its own waste in the future.

“This is not a long-term solution really, because we need to be better to reuse and recycle, but in the short perspective I think it’s quite a good solution,” Ostlund concluded.

The plant, called the Omniprocessor, was designed and built by Janicki Bioenergy and backed by the Bill & Melinda Gates Foundation. The facility would try to prevent diseases caused by contaminated water supplies.

A test plant is up and working at Janicki’s headquarters north of Seattle, according to a blog post by Gates. The first operational plant is planned for Senegal.

“The next-generation processor, more advanced than the one I saw, will handle waste from 100,000 people, producing up to 86,000 liters of potable water a day and a net 250 kw of electricity,” he wrote. “If we get it right, it will be a good example of how philanthropy can provide seed money that draws bright people to work on big problems, eventually creating a self-supporting industry.”

Included is a video of him drinking a glass of the water produced by the plant, which he describes as “delicious” and “as good as any I’ve had out of the bottle.”

“Having studied the engineering behind it, I would happily drink it every day. It’s that safe,” he writes on the post.

The feces is heated to 1000 degrees Celsius, or 1,832 degrees Fahrenheit to draw off the water, which is then further treated to make sure it is safe. But the dried out feces can then be burned, producing enough heat to generate electricity needed to extract the water. Excess electricity can be sold to outside users, as can the water.

Gates says diseases caused by poor sanitation kill some 700,000 children every year. The Bill & Melinda Gates Foundation is making an effort to improve sanitation in the developing world.

“Today, in many places without modern sewage systems, truckers take the waste from latrines and dump it into the nearest river or the ocean—or at a treatment facility that doesn’t actually treat the sewage,” he wrote. “Either way, it often ends up in the water supply.”

http://money.cnn.com/2015/01/07/technology/innovationnation/gates-poop-water/index.html