For most of us, garbage day comes once a week. We gather up all our trash, set it out at the curb, and a big truck comes and collects it, and hauls it away. Voila. Problem solved. But haven’t you ever wondered what happens to all of that trash?
Americans produce an estimated 251 million tons of solid waste per year, according to a 2012 EPA report. To put that in perspective, that’s the equivalent of 2,500 fully loaded Nimitz class aircraft carriers. That’s a lot of garbage.
Fortunately, about 35% (86 million tons) of that gets recycled or composted. Another 12% (about 30 million tons) of it gets converted to fuel, or burned in giant incinerators to generate electric power. But the cold, hard truth is that more than half of our nation’s solid waste ends up buried in landfills. 53%, to be exact; or 135 million tons every year.
Anatomy of a Landfill
The idea behind landfills is to isolate all that garbage from the surrounding ecosystem.
Humongous pits are dug, filled with waste, and then covered up with dirt again. These pits are insulated with a layer of clay, which is combined with a plastic liner, to prevent the waste from “leaching” into the groundwater and polluting the surrounding ecosystem. However, there are some serious problems with this method.
First of all, landfills do not prevent leaching or contamination, they only delay it for a few decades. As the EPA admitted, “Even the best liner and leachate collection system will ultimately fail due to natural deterioration.” At which point, the contents of the landfill will of course escape into the surrounding environment.
Second, burying all that trash in an air tight tomb changes the way it decomposes. As much as 72% of landfill waste consists of organic materials, including yard trimmings, paper products, food waste, and so on, all of which harmlessly compost when left in the open air. But in the absence of oxygen, these materials are consumed by anaerobic microbes, producing large amounts of methane and other “landfill gases.”
Not to mention that the other 28% consists of inorganic materials – mainly metals, glass, and plastic – which may not break down at all in such an environment.
The Great Plastic Dilemma
Petroleum-based plastics, for instance, are not biodegradable. They decay under the effects of ultraviolet light, through a process called photodegradation.
But roughly 30 million tons of plastic is thrown away every year; most of it gets interred in landfills, where it never sees the light of day. Underground and in the dark, those polymers can endure an unknown – possibly indefinite – period of time.
The plastics that don’t make it to the recycling center or the landfill end up discarded on the side of the road. This litter collects in rivers and streams, and is eventually washed out into the ocean.
Out there on the high seas, the stuff does photodegrade – but it turns out that this only makes matters worse, by dispersing toxins throughout the marine environment.
The Search for New Solutions
So, just what are we supposed to do with all that trash? Well, science is hard at work trying to find out.
The EPA is experimenting with new bioreactor landfills, which are designed to aid the decomposition of organic waste and help reduce groundwater contamination, as well as the production of methane and landfill gases.
Some new plastics are being made with additives that cause them to biodegrade in the anaerobic landfill environment. Some are even being made with corn-based “bioresins,” instead of the usual petrochemicals. And surprise discoveries have been made that might help us dispose of even the nasty old oil-based plastics more effectively.
A Canadian teenager named Daniel Burd identified two species of plastic-eating bacteria for his science fair project in 2008. The hungry little microbes were able to break down a plastic bag in a matter of months. And halfway around the world, 16-year-old Tseng I-Ching from Taiwan was able to isolate a bacterium from a mealworm’s stomach. Researchers at Stanford were also able to raise mealworms that were hungry for Styrofoam – one of the most durable and long-lasting pollutants on Earth.
New ideas are coming forth all the time – from giant nets to collect the plastic from the oceans to using fungi to help clean up oil spills. When these and other ideas are fully developed and implemented, we might drastically reduce the impact of human industry on the natural environment, and have a much better answer to the question: What do we do with all that trash?