Myth of Biodegradibility

Over the past quarter century the idea of green business has expanded from a fringe group of hippie capitalists trying to increase environmental consciousness to mainstream corporations trying to establish a global standard for sustainable business. Today, most major companies have social responsibility departments, and moving to greener practices is a priority. Frankly, it’s one of the reasons my business, TerraCycle, is flourishing.

This new landscape is encouraging but full of challenges and pitfalls. A great example is the almost blind embrace of all things “biodegradable.” I used quotation marks around the term because there is disagreement as to what it means. And the debate about whether businesses should embrace biodegradable plastic — P.L.A., or polylactic acid — for use, say, as packaging or in utensils, is an important one.

The challenge that biodegradable plastic purportedly solves is what happens when the product becomes garbage or hits the end of its useful life. Many products, like a plastic coffee cup, are simply not recyclable in most global recycling systems. Therefore, if you are an independent coffee shop (or even a national one) you typically have three choices: You can do away with the plastic cup and use another form of packaging that is recyclable or highly reusable (like a reusable cup made from glass). You can team up with a company like TerraCycle, which offers national programs to recycle otherwise nonrecyclable waste (our program for plastic cups, sponsored by Solo, collects this stream of waste and recycles it into a variety of plastic products). Or you can use biodegradable cups.

The obvious benefit of biodegradable plastic is that it has the perceived ability to decompose when it becomes waste. As with many green practices, however, the devil is in the details.

When you look at any object it is important to look at both how it is made and how it is disposed of. With biodegradable objects, it is disposal that is the problem. Something made from biodegradable plastic will not decompose thoroughly in a landfill, because oxygen is required for such material to decompose properly and landfills have very poor oxygen flow. That means that throwing the biodegradable cup into the trash is basically as bad as throwing a normal plastic cup in the trash.

You also shouldn’t throw that cup into a recycling bin because it is still not recyclable and will in fact harm the quality of the plastic made from recyclable material like soda bottles. How about composting the cup at home? Well, even if you are willing to carry the cup with you all day and then back to your home, and even if you happen to have a composting pile (as do about 5 percent of Americans), you will still be out of luck because most consumer compost piles do not get hot enough and are not maintained well enough to decompose a complex material like P.L.A.

That leaves one option: in a small number of American cities, like San Francisco, where there is municipal green waste collection, you can put the cup in such a system and it will be properly composted. Fundamentally this limits the practical use of biodegradable plastic to a handful of ZIP codes. But even then, the solution is less than satisfying. It took lots of energy to turn soil and plant into biodegradable plastic. When that plastic is composted back into soil, all of that energy is effectively wasted. The most efficient use of the energy would be to make the plastic and keep it as plastic as long as possible.

Clearly, the optimal solution is to use materials that can be recycled or reused, allowing complex materials (like plastics) to remain complex materials. So why is biodegradable plastic so popular?

Simple: it’s perceived to be a silver-bullet solution. You buy a product, and when you throw it away it will disappear. The truth, though, as with many green initiatives, is more complex.

So what has this meant for TerraCycle? Practically, we have found that many companies that are offering biodegradable plastic can team up with us so that the material can be collected and processed properly. More generally, the realization that most environmental choices are more complicated than they seem has forced us to keep questioning fundamental assumptions, especially since we have positioned ourselves as a leading green business.

 Tom Szaky