On biodegradable products

11 Jul 2007

Got questions about the environment? Ask Umbra.

Dearest Umbra,

With biodegradable corn-plastic products like clothes hangers, credit cards, and trash bags, we are led to believe there are good alternatives to plastic that can be thrown out guilt-free. But doesn't all trash get put in landfills that are then hermetically sealed to prevent the bad contaminants from leaching out, but hold in the things that would have been composting otherwise? I thought that was the reason to compost organic matter: to reduce anaerobic digestion in a landfill that causes methane production. So what's the deal with alternative plastics? Is it a scam? Should it be put out with the food scraps? Help!

Andy Goodell
Oneonta, N.Y.

Dearest Andy,

If you wish to stick a corn-based coat hanger in the worm bin, or bury it, I will eagerly await the results of your experiment. A little niggling on the rest of your question: some trash is incinerated, which comes with its own problems. And there are several reasons to compost organic matter -- yours being one, others including making high-quality soil amendments, reducing municipal or personal waste costs, decreasing incinerated matter, or just plain having fun.

How green is your garbage?

Photo: iStockphoto

The subject line of your question asked, "What does biodegradable really mean?" Degradation is simply breaking down into component parts, with chemical transformation in the process, perhaps. Biodegradation implies that degradation takes place within nature, and as you mention, in a landfill process the elements of nature that would degrade your corn-based coat hanger -- air, water, aerobic microbes, to name a few -- are not particularly present. Hence, alternative plastics may or may not be biodegradable to the extent that you imagine.

There are a few standards for biodegradability to which a producer might adhere, but little oversight for those using the word. The Federal Trade Commission is in charge of deceptive advertising claims, and has put out some general guidelines for all environmental claims on products. They would like it if the word biodegradable were used only to "mean that the materials will break down and return to nature within a reasonably short time after customary disposal. What a 'reasonably short time' is depends on where the product is disposed."

The FTC also cautions consumers to critically read all eco-labeling claims, which is great advice and will help clarify your imaginings. If a producer has a substantiated claim about the low impact of its product, it should be able to give details. You might imagine, for example, when you see the "biodegradable" claim, that the product will biodegrade at your landfill. "Biodegradable in landfills" would be an example of a clarifying label.

Another standard of biodegradability is the voluntary testing guidelines set by the standards organization ASTM International. They have guidelines for degradation in composting operations, in water, in anaerobic conditions, and I'm sure many others. Unless the producer specifies they have used the ASTM standards, you would need to inquire to find out.

Usually the only way to know the true biodegradability of a product is to call the producer and ask: If I put my corn-based coat hanger in the landfill, how long will it take to degrade? Hopefully they will be honest. The coat hanger may not degrade naturally, but perhaps it would if run through an industrial composting process replete with chipping and high temperatures.

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As to your final question, are alternative plastics a scam, I think an argument could be made that they are. But the argument would be built on the incomplete knowledge of consumers and the uninformed assumptions we make about alternative plastics.

If we don't have all the information -- and how could we, really -- we tend to fill in the gaps with our wishful thinking. Knowing plastics are a trash problem, we wish that someone would replace them with a trash solution. Knowing that petroleum is bad, we hope that corn is good. In one example of reality, plastics with non-petroleum ingredients, such as corn plastics, may also include petroleum-sourced components. It also of course takes quite a bit of petroleum to grow and process corn into coat hangers. Replacing petro-plastic products with bio-plastic products retains some of the same problems of trash generation, disposal, and non-degradation, and adds some odd ones such as potential pollution of recyclable plastics with currently non-recyclable corn plastics.

But I'm not sure the scam argument could hold water if our only claim is being led astray by our own wishful thinking.

Fairly,
Umbra

Yours is to wonder why, hers is to answer (or try). Please send Umbra any nagging question pertaining to the environment -- but first check out her FAQs!

The claims made in this column may not reflect the views of this magazine. Neither the magazine nor the author guarantees that any advice contained in this column is wise or safe. Please use this column at your own risk.

Umbra Fisk is Grist Research Associate II, Hardcover and Periodicals Unit, floors 2B-4B.

Comments: (5 comments)

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Biodegradable Products

First off, I hate posting and someone is sure to post something snarky thinking I'm being snarky, but I just wanted to share some info.
I've been working on an organics recycling program all summer, and have discovered a lot about biodegradable products. First, a good website to check out standards on biodegradable or compostable products is www.bpiworld.org. Second, most biodegradable or compostable products will take a long time to break down in a "backyard" compost as most "backyard" composts do not have high enough temperatures, or lack N or C, or another key ingredient to make awesome compost. Third, there are biodegradable or compostable products that are made by other organic matter than corn. Finally, get your village, town, city, metro area or country to start organic recycling programs, where these bio/compostable products make the most sense to use. There are several cities in the U.S., Canada and Europe that have organic recycling programs, removing food waste and other compostable items from our waste streams, and use products that are compostable and approved by BPI.

Thanks for letting me share my 2 cents.

by logocat at 10:47 AM on 11 Jul 2007

Experiment in composting plastics

Last summer my wife and I has a series of garden parties/potlucks. While we encouraged folks to bring their own reusable tableware, for the slackers we bought some unbleached fiber plates and compostable, I think corn, plastic utensils and cups (sorry, I don't remember the brand). These materials were added to the compost and subsequently covered as the pile built up. We also added some plastic containers for dates, strawberries, etc. that were labeled as compostable. The compost was not turned, just built up in layers in a one square yard footprint slatted plastic compost bin. I turned the compost in the first part of June and sifted finished compost. All the plates and most of the cups and containers were gone, but the utensils were still there and looked basically pristine. I'm not sure how many years it will take for them to break down. It seams like a commercial or community-sponsored composting program where all the material is chipped up would be a better disposal option for this type of plastic.

by matrogers at 11:21 AM on 11 Jul 2007

GMO or non-GMO?

I remember being super stoked when I first heard about biodegradeable corn plastics. However, my enthusiasm was brought down several notches when I looked further into it and discovered that at least some corn plastics are made from genetically modified corn. In fact, it seemed as if this was a deliberate effort by those that would raise/market/promote genetically modified corn to "green up" their image. (I don't have the research on hand at the moment, but much of it was available online about a year ago.) That being said, I hate to tarnish the entire corn plastic industry since there may be some less nefarious outfits not using GMO corn. However, if it comes down to choosing between petroleum-based plastics and GMO-corn ones, seems like it's time to just cut down on our plastic use entirely, and re-use and recycle what we do use as much as possible.

(I also seem to remember a lot of hype about biodegradable plastics in the early `90s, but it turned out (if memory serves) that they were held together with non-biodegradable plastic polymers--when the biodegradable component broke down, the plastic polymers were free to leach into the ecosystem.)

by wilderness at 11:36 AM on 11 Jul 2007

Types of B-D plastic, types of landfills

A couple of comments on the comments:

There are several ways to make biodegradable plastic. One is to use biologically-based polymers that may or may not break down in a composting facility or a landfill. Another common technique is to use mostly petro-plastic, but insert bio-plastic monomers into the plastic as it is made. Plastics made with these hybrid polymer chains will break down into smaller pieces quickly, but will still leave tiny particles that will not degrade. I call this "out of sight, out of mind" plastic.

There are also different kinds of landfills. The "dry tomb" design tries to isolate waste, and make sure nothing gets in or out. Another type uses soil between lifts. Depending on the content of air and organic matter in the soil, aerobic degradation may occur. Anaerobic degradation (which is much slower) occurs in many landfills. The end-product, methane gas, is often captured and used to produce energy.

But there is no guarantee that degradation won't occur in a dry tomb, or that it will occur in the other types. Bill Rathje once studied landfills across the USA, and found no consistent pattern of degradation. He found 60-year-old newspapers with the headlines still readable in some landfills, and paper turned to mush in others. Local climate had less of an effect than he anticipated.

The best solution is to do what matrogers did: At an event where you typically use disposable items, do your best to use reusable ones. The first 'R', 'reuse', is always the most effective, because the use of the second (reduce) or third (recycle) always results in the fifth: residual.

geobeck

by geobeck at 12:13 PM on 11 Jul 2007

Waste Diversion with BPI Certified Disposables

As a sales/consultant to the foodservice industry, let me say that the bio-based or BPI (Biodegradable Products Institute) certified products are a huge growth industry & heres why.
1. In-house cafeterias of heathcare facilities schools & universities are lowering their solid waste tipping fees by implementing a waste diversion program utilizing bio-compostable plates, cups, containers,cutlery & unbleached dispenser napkins that are made with

PLA (corn) resin instead of #6 polystyrene
switch grass, sugar cane stock & talc
pre-consumer milk carton waste scrap
post consumer recycled paper

These bio-compostable packaging items are then thrown into bins & roll off containers along with compostable food scraps and taken to commercial compost facilites such as the Intervale here in Burlington Vermont. It is processed the most efficient way possible which is commercially. The Intervale profits from this nitrogen-rich compost created by a mix of BPI certified bio-compostables & food scraps. The healthcare facility enjoys a 70% savings on waste disposal costs through this diversion process. The savings pays for the compostable packaging.
BPI certified products which adds credibilty and guarantees there will be no contaminates into the compost heap.

Conclusion: Corn based plastic is only the 1st generation resin used to make some of these products. There will be other biobased resins made with soy bean oil, palm oil, sunflower oil etc. There are also biobased commercial cleaning products made with these non-petroleum oils to form the base detergent system to a green cleaning product.

My advise is to leave the composting of these bio-plastics up to the commercial facilities, not your backyard composter. Use reusables at home & when youre in a takeout establishment that uses disposables such as syrofoam (polystyrene) or polyethylene coated paperboard, recommend they look into bio-compostables as an alternative to the petroluem based packaging that are BPI certified as that criteria means the item fully degrades in a commercial composting environment.

by hughesey at 7:13 PM on 11 Jul 2007

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On biodegradable products