Breaking the Mold

Plastic can be made from other natural polymers besides petroleum, such as  starch and vegetable oil (see This Startup Is Making Compostable Plastic Out of Seaweed). Some types of these “bioplastics” can be turned into compost. Today, food service offers the greatest potential for biodegradable plastic. These containers and utensils do not require cleaning before being placed in the compost. And composting avoids contaminating other recycled materials while also saving water. Other biodegradable plastics are commonly found in trash bags for municipally collected compost.

Biodegradable plastics will not decompose in home compost or in typical landfills.

However, biodegradable plastics do not entirely live up to their promise. They will not decompose in home compost or in typical landfills; they must go to a commercial facility to be exposed to elevated temperatures. And not all bioplastics are even designed to be biodegradable. Even so, unlike conventional plastic made from petroleum, bioplastics are made from renewable sources, and many of these new plastics require considerably less energy and fewer hazardous chemicals to manufacture.

Wax moth caterpillars are known to eat polyethylene; in a waste dump in Germany Pseudomonas bacteria were discovered to be eating polyurethane.

Bioplastics do not enjoy the same advantages that originally spurred the development of petroleum-based plastic. Unlike the first plastics, bioplastics compete with materials that already perform well and are less expensive. But as with other environmentally hazardous products such as fossil fuels, the full cost of plastic includes its “externalities,” so its true price should include the cost of disposal. One solution is to subsidize the development of new plastics, through either fees collected from large manufacturers or tax incentives for new development.

Nature Fights Back

For all of their durability, plastics are not immune to attack from living things. Wax moth caterpillars are known to eat polyethylene; in a waste dump in Germany Pseudomonas bacteria were discovered to be eating polyurethane, another widely used plastic component that cannot be recycled and releases toxins as it degrades. And in Japan, scientists discovered the bacterium Ideonella sakaiensis eating PET. Although PET is recyclable, most PET is thrown away and much of that is contaminated with food waste. Having PET eaten by germs sounds like a good idea.

Plastic Munching Bacteria

Researchers at Stanford University are evaluating mealworms to consume polystyrene (“Styrofoam”), one of the most problematic plastics for disposal. Mealworms will eat plastic and are used as feed for chickens and other livestock. There is some concern that feeding plastic to mealworms and then feeding mealworms to livestock could possibly concentrate even more toxins in our food – polystyrene contains a suspected neurotoxin that is being phased out in the EU. But results so far show that the worms can consume the plastic and then safely eliminate the toxins from their bodies.

Speeding Up Nature

The idea of nature adapting to our careless mistreatment has a basic appeal that is likely to keep this research moving forward. “When you have huge amounts of plastic in the environment, that means . . . there will be evolution to use this as food,” says Hermann J. Heipieper, an environmental scientist in Germany. As promising as this sounds, practical applications of “plastic predators” are not close. The processes are very slow and the habitats are complex, which means they are expensive. And there is a lot of plastic waste.

But we can artificially mimic the processes that dissolve plastic in the guts of microbes. By combining chemical recycling with better conventional recycling, we can return almost all types of plastic to their basic components—from which any new plastic could then be made. Plastic could be used indefinitely and never become waste. This possibility is called “the circular plastic economy.” At present it is too expensive to be commercially viable, but it holds great promise, and billions of dollars are being invested in its development.

Chemical recycling is a catch-all term for a variety of ways to essentially reverse the process of making plastic (not all of them actually make new plastic). Some forms turn recycled plastic into fuel. Chemical recycling isn’t fussy about the color of the plastic or if different types are mixed together. It can recycle plastics that cannot now be recycled. Making new plastic from the digested output also has the potential of reducing by about half the carbon dioxide now emitted in plastic manufacturing.

This process must be done carefully though, or all of its benefits will be lost. Today most processes require so much heat and expensive enzymes that widespread chemical recycling doesn’t make economic sense, and it’s so far not even possible for some plastic waste. Nevertheless, the process has advanced enough that dozens of startups, such as Mura Technology in the UK and Novoloop in California, promise to sell some types of plastic stock from chemically recycled waste.  How to Recycle Any Plastic.

The Deep Blue Clean Sea

Disgust over ocean garbage has spurred individuals to action. Dutch teenager Boyan Slat gained a good deal of attention as well as venture capital when he founded The Ocean Cleanup to develop a retractable boom for removing floating plastic trash. And the nonprofit Ocean Voyages Institute is enlisting the help of commercial shipping to identify ocean trash. It distributes GPS markers to shippers who place them on large concentrations of plastic that they encounter. A trawler then collects the garbage from that location.

On average about 80% of the plastic in the oceans comes from ten rivers.

But it is far easier to prevent plastic from entering the ocean than to remove it once it’s there. According to a report in Scientific American, on average about 80% of the plastic in the oceans comes from ten rivers: two in Africa and the rest in Asia. New ventures like Mr. Trash Wheel and Plastic Fischer are at work to remove plastic from rivers before it reaches the ocean. The Ocean Cleanup has joined this effort, with plans to clean 1000 rivers in the next five years.

Nine European countries recover more than 80% of their plastic waste.

Where do we go from here? Change is not only possible, it is already happening. Nine European countries recover more than 80% of their plastic waste. Governments around the world are responding to the outcry of their citizens (California, Canada). Some companies, such as Coca-Cola, Marriott and Dell Technologies, have pledged major changes in the way they use plastic. There is no single solution; success will be a combination of efforts, including:

• Limit plastic, especially single-use plastic, to essential uses only.
• Develop plastic that is truly safe to be in contact with food.
• Make disposal of all plastic safe and completely effective.
• Remove as best we can the plastic already in the environment.
• Develop new plastics that are truly biodegradable.
• Develop recycling that returns used plastic to virgin material.

Change won’t always be cheap or convenient, but for too long we have been living off our planet’s capital without a thought to the future. The cost of continuing business as usual will far exceed the future cost of correcting our neglect. We have no choice but to deal with these problems, or they will surely deal with us.