Monday, November 30, 2009

Biodegradable = Scam

I saw a lot of good money spent on "biodegradable" cups, plates and trash bags this past week.

For those of you who've never had a tour of a landfill, nothing rots in a modern landfill.

Modern landfills permanently entomb trash within impermeable layers of rock and plastic sheeting (see pic.), compacting the refuse into a dense, anoxic environment that prevents the infiltration of water or air (and therefore any real amount of biological decomposition). This is a good thing! The last thing you want is for a city's worth of old batteries and diapers to corrode and seep into the groundwater. Completed landfills are sometimes covered in grass and converted to golf courses or parks, but trees can never be planted due to the disruptive impact of their deep roots.

I find the biodegradable sales pitch especially disingenuous when it comes to "compostable" plastic products made from corn. These plastics are only compostable under rigorous, professional conditions. If you throw them in any old pile, they'll be around for years just like corn cobs or wood.*

I don't see cutting down on landfill space as a big environmental priority at any rate (especially in a country with as much surplus wastelands as the U.S.). I'm a lot more concerned about slowing the paving over of our best wildlands and agricultural soil, and conservation that limits the oil and mining-intensive production side of consumption (as opposed to just figuring out how to throw out what we're done with).

Use it up, wear it out, fix it up or do without...

* Has anyone actually tried to compost these corn plastics? Did it work? What are your conditions?


  1. I think you should get a hold of a couple of these biodegradable plates and throw them in your compost heap and see what happens. Heck, maybe I will. I don't normally go in for dispossable stuff, but I might have to make an exception for this experiment.

  2. a great idea! unfortunately, I live in an apartment at the moment...

    if you try it, let me know how it turns out!

  3. Thank you for this! I've been convinced of this for a while now. Not to mention using FOOD for things other than food. Like disposable plates and fuel. Ouch!

  4. Save yourself the time on the experiment- it was done by a group who wrote the article "Corn Plastics to the Rescue", Smithsonian Magazine,Aug. 2006. A guy put a plate in his backyard compost for 6 months. It did not change one iota. These PLA plates are certified ASTM 6400 which means they will compost in commercial and municipal composts that have higher heat and more moisture than a backyard compost.The kicker? There are only 88 of them in the entire US. And the "Big Lie", as I call it, is that PLA uses more fossil fuels than normal plastic. They hide this with buying energy credits. But there are plastic products that are landfill biodegradable. Look for certification ASTM 5511. They have the ability to biodegrade anaerobically in a landfill. As mentioned above, landfills are airless. So you have to have something that will biodegrade without oxygen.

  5. thanks for the detailed info, Leslie!

  6. i know of at least one fast food place that lets you sort your garbage into a composting bin that is then sent to a commercial composter. i've been to a grocery store that does that as well. seems like a real solution to the problem, and very easy to implement.

    also, increasing the composting rate of the PLA might just be a technical challenge that could be overcome in decade or two.

  7. Don't worry Mat - Landfills will soon be mined for their resources - (Remember that late night discussion...)
    Besides landfills create Methane which is a wonderful greenhouse gas. I am sure recapture systems will become more widely used and we will have another source of energy for the consumer.

  8. @ Doc Almond
    I certainly do! speaking of which, is it too late for me to get a bacon tour tshirt?



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