Dig Deep Into How Landfills Work

Here in America, you can’t understand our waste structure without a fundamental understanding of our landfill system. According to the EPA, almost exactly half of all our waste ends up in a landfill, or 146 million tons of the 292 million tons of municipal solid waste produced annually. So clearly this is not something to be overlooked.

Graph Courtesy of the EPA

While landfills can often get a bad rap, it makes sense that they are as prevalent as they are today. For starters, with the amount of land the US has, burying it seems like the most obvious solution to our excessive amounts of garbage. It’s also relatively cheap. While I’m a firm believer in the potential of things like recycling and industrial composting facilities, those options can be more costly to maintain and require extensive machinery investments. Although landfills also require initial investments and aren’t just as simple as putting our trash in a big pit, they historically have been more profitable.

Despite the challenges we have with our waste, when you look at the history, it really is impressive how far we have come. Prior to the 20th century, most people were simply burning their trash or burying it on the outskirts of town to avoid the risk of disease. It wasn’t until 1937 that anything close to a modern landfill was created. The first one was in California, but due to a lack of forethought these initial landfills were environmental disasters. These ‘dumps’ were essentially giant pits in the ground that we filled with garbage and covered with dirt. They were consistently leaching chemicals through rainwater into our soil and waterways, and they were outputting extensive amounts of greenhouse gases. 

By 1976 things started to change with the launch of the EPA’s Resource Conservation and Recovery Act. Among many other things, this act put in greater restrictions for how landfills had to be made. Some of the biggest changes included liners to stop wastewater from escaping and gas vents for gas collection.

Image Courtesy of OC Waste & Recycling

The above image shows an amazing breakdown of how our landfills are made today (click on the image for a closer look). Despite often being considered dirty, they are an engineering-feat. To start off these operations, wells and probes are dug in the surrounding area. These probes confirm that there is no ground water contamination or gas escaping through the sides or bottom of the landfill. To stop anything from escaping in the first place the landfills are lined with both plastic liners and often clay soil to add an extra layer of protection.

One of the biggest challenges that happened with old school dumps is whenever it would rain the water would seep through a landfill and collect toxins and chemicals. This liquid, referred to as leachate, is precisely what was contaminating water. Instead of just allowing this leachate to collect and pool at the bottom of landfills, they have piping systems running around the landfill to collect it. After being collected, this leachate can be sent to water treatment centers.

One of the most common misconceptions that I run into is how things breakdown in landfills. There is in fact very little decomposition going on inside a landfill. When our trash is deposited into the landfill, it is very densely packed together and the vast majority of space that would be remaining is filled in with soil. The result is that only a small portion of all the material placed in a landfill is able to degrade using an aerobic (with oxygen) process. Shortly after all the oxygen is consumed by bacteria doing the work of degradation, the landfill is only left with bacteria capable of anaerobic degradation (without oxygen). Not only is this process of degradation slower, but the main output is methane gas.

Methane gas is somewhere between 28-36X more harmful than CO2 to our greenhouse gas effect on our planet according to the EPA. The worst part is that our landfills account for approximately 15% of all our methane creation in the US. On the plus side many facilities now harness that methane out of the landfill and burn it for energy. Lucky for us, burning methane converts it into a less harmful greenhouse gas (CO2) and creates energy.

So since their beginnings, landfills have come a long way. They produce less destruction than in the past (short of the landmass disturbance) and even provide opportunities for energy collection. However, like I previously said, our trash isn’t degrading in our landfills. It doesn’t matter if you buy a plastic or bamboo toothbrush. If the final destination is a landfill, their fate is the same; one of stagnation for countless years. This is where “Reduce, Reuse, Recycle” becomes so important. If we really want to reduce the environmental impact of our waste, it starts with reducing our trash production. Separating your trash into compostables and recyclables is the best way to send as little waste to the landfill as possible. Think twice next time you reach to toss something in the garbage can: Do you really want it to be sitting in the ground for an eternity?