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In One’s Cups

By on April 10th, 2012

Tom Szaky, blogger for Packaging Digest, has a good post over at the New York Times, which he follows up on his PD blog, about the distinction between biodegradable plastic and plastic recycling. Which is “better”? Starting over at the Times:

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.

The trouble with home composting is that the average backyard compost heap doesn’t get hot enough to biodegrade plastics like polylactic acid (PLA). So what is to be done with it? As Szaky says, some cities have collection centers that have the capability to compost such products effectively. Ay, there’s the rub:

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.

Like many ostensible solutions, biodegradable plastic “feels right,” even if it might not necessarily be.

The story continues over at Packaging Digest:

Recycling still takes energy, which composting does not, but solely composting limits the end-of-life value of a product too much to give it precedence over recycling–especially when composting of biodegradable plastic still isn’t available on a large scale. Also, making a new product requires energy anyway, so the output of energy to recycle a product would be matched by that of a new product regardless.

Ultimately, recycling vs. biodegrading is not an either/or situation, and both options have their advantages and disadvantages. Decisions need to be made on a case-by-case basis. Choose wisely!

What I personally prefer is to try to choose products carefully so it’s not a decision I have to make. Sure, it’s not always possible, but one tries. Take cups (please!). My gym has a bar at which they sell recovery shakes, served in large Styrofoam cups. At first, I would buy one shake then repeatedly rinse out the cup and reuse it from day to day, until it became structurally unsound and it oozed all over me as I walked home. The solution? They will gladly use a container of my own, such as a sturdier bottle (like a water bottle). I am also not above bringing my metal travel mug into a Starbucks and let them figure out if it’s a venti or whatever.

  1. 3 Responses to “In One’s Cups”

  2. By Dean Louis on Apr 12, 2012 | Reply

    Tom Szaky brings up many good disposal points -the related dilemma of what to do with large quantities of plastic waste. Veg or corn starch based plastics inherently must to use large areas of arable soil along with large volumes of water /pesticides to produce the corn. There is moral issue related to producing bio-plastic when increasing numbers of people are starving around the globe. The energy use to create this derived PLA based material, then has to be converted (with difficulty) into a usable plastic material, a product that cannot be recycled or dare be mixed up with any recovered plastic material to enter the recycling stream. Recyclers intensely dislike any form of so-called biodegradable plastic because of contamination issues.
    But there is hope-there are newly discovered truly sustainable affordable bio-renewable materials that maybe substituted into plastic products, partially replacing a portion of the fossil fuel petro-chemical resins. These would help to limit the rapid depletion of these raw materials, as well as lower /reduce the plastic products carbon footprint. Interestingly these materials are cost competitive compared with conventional plastic resins.
    Interestingly enough, these bio-renewable materials don’t cause any recycl-ability issues and the material when disposed of, is attractive to common bacteria who will consume as an edible food = biodegradation.
    This new material is called ESP 300 bio-renewable resin, a new dimension for plastics.

  3. By Dr Ross Headifen on Apr 13, 2012 | Reply

    There are many inaccuracies in this article that if not bought out can misinform a reader of the actual process.
    1) The word Biodegradable at the consumer level is horribly misused. it comes down to where the biodegradation process is engineered to happen by the manufacturer. There is;
    a) compost biodegradable where a product will only biodegrade in commercial composting conditions. Plenty of oxygen, temps above 60 deg C and moisture. Not home compost piles. Even then many composters will not take compostable plastic as they clog up their processes. Commercial compost facilities are few and far between and there is no special collection of compostable plastics, so this renders the concept of compostable plastics not a user friendly option.
    b) There are landfill biodegradable additives that when added to plastics they will biodegrade in a landfill with moisture. This can be with or with or without oxygen present. (See http://www.goecopure.com for an example).
    c) There is oxodegradable additives which is not biological but a chemical reaction that causes the plastic in the presence of oxygen to fragment into little pieces. This is actually worse for the environment. This is what the author is confused about, but is correct they will not break down in a landfill due to lack of oxygen.
    2) Compostable plastics biodegrade to CO2 and any energy that was stored in the plastic is lost in the biodegradation process.
    3) Landfill biodegradable plastics when biodegrading in a landfill without oxygen present produce methane, CH4. This gas can be captured to combusted to produce energy or Electricity. i.e. the energy in the plastic is recovered.
    4) Oxodegradable plastics do nothing but make lots of little plastic bits that get into the water ways and our environment. That is not what we want.

    Recycling is what we should do first. But if every piece of disposable plastic was made with a landfill biodegradable additive in it, then if the item was recycled 10 times before it became unusable for some reason and it was sent to a landfill, then it would break down. For those modern landfills that capture the methane, we would get its energy back. We call this the BACKSTOP method for plastics as no matter if the item is recycled or landfilled, either way the plastic item is gone and not sitting as plastic waste for the next 300 years. Why should our future generations deal with our plastic waste that we used just because it provided us a few minutes of convenience for us to use?

  4. By Pat Berger on Apr 15, 2012 | Reply

    DR. Hedifen I really like your view and opinions on plastic.

    What about another view of the plastic problem.
    In packaging, food distribution or consumption it is going to be used 1 time so recycle or use as fuel. Do not landfill at all. If it cannot be recycled it is fuel nothing else. Don’t bother with biodegradability.

    Dr. at what point in the lifecycle of the used plastic could the most BTU’s be extracted?