Back to the story of the leaf bags down at the Garland Community Garden . . .

I've gotten quite a response in regard to an article I wrote regarding these bags and I'm pleased at the interest and the opportunity to discuss an important issue that apparently a lot of folks don't understand:  the difference between photodegradation and biodegradation.  Although the end results often look the same, the two processes are entirely different and have entirely different requirements.

Some folks have written they don't think that a plastic bag lasts 500 years in landfill when the truth actually is that 500 years is a conservative estimate for their duration in a landfill.  Some scientists postulate they don't ever break down.


"I have plastic bags in my yard that are brittle and fall apart within two years."  Yes I don't argue with this comment made by one of my readers.  If any of you have ever joined our twice a year Trash Bash sponsored by Keep Garland Beautiful, then you too know this is a fact when you reach to pick up a plastic bag and it crumbles in your hand.  These bags that we see falling apart outdoors have not biodegraded.  They have photodegraded and that is an important distinction to understand if you care about the environment and future generations.


Photodegradation is the alteration of a molecule by photons, particularly those wavelengths found in sunlight.  However, even artificial light will induce photodegradation, which is why we are asked not take flash pictures of artifacts in a museum.  Over time the light from these flashes will photodegrade the artifact.  Oxidation is another process associated with photodegradation.  Simply put, oxidation is the reaction of a substance with oxygen.  This also explains why we sometimes see precious artifacts under glass in museums—to prevent their exposure to the air.


Biodegradable simply means to be consumed by microorganisms and to return to compounds found in nature.  Compostable materials are those that break down in a compost pile.  Organic material can be aerobically with oxygen (which is typical of most compost piles in people’s yards) or anaerobically without oxygen (a process that typically requires more sophisticated equipment).


Modern Landfills

According to the National Solid Wastes Management Association, modern landfills are not designed to break down waste.  They are designed to store it forever.  In a modern landfill tightly packed mounds of waster are sealed under a rubber and clay barrier, and over a liner that keeps the liquids from leaking out.  But garbage in a landfill over generations of people does decompose anaerobically in this sealed, oxygen-free environment.  However, because of the lack of oxygen, bacteria in the waste produce methane gas, which is highly flammable and dangerous if allowed to collect underground.  It is also a potent greenhouse gas and contributes to global warming.  Some landfills vent this gas into our atmosphere and other landfills are designed to capture it and use the gas as an energy source.


Rethinking Organic Waste as a Potential Money Maker

Most of the leaf bags we set out on our curbs in Garland go to the landfill.  Also all of the tons of spoiled vegetable produce from all the grocery stores in Garland goes straight to the landfill—literally tons of organic waste every week filling up our landfill.

This organic waste could be used as the basic material to create a business that could generate income for residents and provide compost for local gardeners—thus helping to lift up our local economy.

What can you do about it?  Perhaps more than  you may think.

If bothers you that we are literally throwing our money away by burying it in a landfill, please attend the Volunteer Conference on Tuesday, January 27 from 6 to 8pm at the Granville Arts Center Atrium and sign up to be the project leader for a team that Loving Garland Green is organizing with the assistance of some City officials to study the possibility of a composting service here in Garland, Texas.


Perhaps We Need to Rethink Our Criteria of "Beautiful"

Is it more “beautiful” to see plastic bags filled with leaves waiting in a garden to be used for soil than it is to have them taken to a landfill and hidden from sight forever?  These plastic bags, many of them as tough as 8 mil plastic, make fairly good compost bins if they are loosely packed.  Just put a little water in them and shake them around.



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