We Have A Recycling Problem

We all love to recycle. But is it really as great as we think it is?

A version of this blog post originally appeared on my website. But I decided it was time to update it, after some fascinating conversations about what AI can do for biology. Read on to find out how AI could help us solve our recycling problem.

Let’s talk about recycling.

A decade ago, recycling was all the buzz—the solution to our giant waste problem. A pipe dream of a circular economy, where we finally stop pumping oil out of the ground and dumping plastic bottles in the ocean. But today, it seems recycling has lost its media appeal. What happened?

Turns out, recycling is not the panacea we thought it would be. Most people do not realize how difficult and inefficient the process of recycling is. Making a new product from recycled plastic requires exceptional purity of input material, which means the plastic items have to be sorted and washed extensively, requiring a lot energy and water. There are also strict regulations when it comes to the material source if the reclaimed product is to be used for food packaging. What’s more, plastic can only be recycled 2-3 times before it becomes too brittle to make anything out of it. Finally, most packaging, like milk cartons and frozen dinner packages cannot be recycled, as those are made of composite materials (layers of paper, plastic, and metal) that are impossible to separate effectively.

The U.S. recycles only 5% of all its plastic. So, when you sort your recyclables, it is highly likely that they all end up in the same place: a landfill. China, which had handled nearly half of the world’s recyclable waste, banned the import of plastic materials back in 2018. For the U.S., processing its own plastic waste is just too costly. And with the few existing recycling facilities already operating at capacity, some recycling trucks get turned around and sent to landfill sites.

Don’t get me wrong, I love recycling: it is a behavior that has been instilled in me since my high school days, which I spent in a far corner of Wisconsin, at a boarding school called “Conserve School”. I still believe that the act of recycling is useful because it helps us develop a more conscious attitude toward consumption, which will hopefully help us break away from the current paradigm of wastefulness.  However, it can also give us a false sense of righteousness about doing something to help the environment. When you put your cardboard boxes and aluminum cans in the recycling bin, it does not feel like you are generating trash because they go into a clean green dumpster that has an “eco” sign on it. In reality, it is still trash—the recycling waste is simply out of sight and out of mind.

Despite its noble intentions and virtue-signaling potential, our current approach to recycling does not actually make a dent in the amount of resources we use, as economic and environmental analyses of the impact of recycling have shown. As cynical as it may sound, at this point in time, the biggest benefit of recycling is making you feel good about yourself. 

Thinking outside the bin

This all sounds pretty grim, but there are alternative technologies that are being developed to help us solve our waste problem. A number of companies are implementing a new process called chemical recycling. Instead of mechanically processing plastic materials, chemical recycling uses enzymes and solvents to break them down into pure starting molecules, which extends the number of times plastic can be recycled without losing its quality. This process, however, requires high temperatures and uses harsh chemicals, making it not the most environmentally friendly method. 

Other researchers have turned to plastic-degrading microorganisms. Scientists have discovered many organisms that evolved to eat plastic and are now looking into how to harness this ability for the remediation of plastic pollution. There is a possibility of using these organisms in industrial settings, similar to current recycling plants, to degrade waste materials and convert them into new valuable products. Unlike recycling, biological processing does not require pure starting materials; in fact, microbes thrive in the presence of food particles. On top of it, it is possible to “upcycle” waste plastic by converting it value-added products—an alchemical transformation that only biology is capable of.

The advantage of using microorganisms for dealing with plastic waste is that they do not require high temperatures or harsh reaction conditions. They can grow on food-contaminated material, which simplifies the pre-treatment process. They also do not generate harmful byproducts. In fact, by using different types of organisms in the same reactor, it is possible to achieve a carbon-neutral outcome where the CO2 produced in the process is used by other microbes to make useful products. This could actually make the operation of such biorefineries economically profitable.

The biggest challenge in executing this ambitious plan is that it is hard to find organisms that are capable of degrading plastic so efficiently as to make it useful on a practical scale. The naturally occurring microbes degrade plastic at a very slow rate.

This is why some companies are turning to AI to improve the efficiency of the enzymes that break down plastic. The way it works is very similar to ChatGPT: you provide it with enough text to spot different patterns, for example, recognizing legal language or someone’s unique writing style. In the same way, computational biologists feed enzyme sequences to their AI algorithms to teach them to recognize features that make the enzyme more efficient at its job. Then, they synthesize and test those enzymes in the lab to see which ones have the desired functions.

It’s a work in progress, but I believe that biology will have the solution we are looking for—and that human ingenuity and AI tools can help us to get to that solution faster. In the meantime, you can do your part to reduce the consumption of unnecessary products and use your consumer influence to convince companies to minimize packaging and use more sustainable materials. Remember that there is ‘Reduce’ and ‘Reuse’ before ‘Recycle’? Those steps have a much greater effect on sustainability than recycling does. 

You do not need to be a scientist to make a positive impact in the world. Everyone’s actions and efforts add up to much more than what any one of us scientists can achieve.