How Landfills Work- Mountains of Garbage
How Landfills Work
Mountains of Garbage
You may have seen them. You see a random mountain in the middle of the countryside. You may see trucks climbing these monolithic heaps and you could have seen a similar video above. What you are seeing is a hydraulic tipping machine that lifts the trailer into the air an allows gravity to push the trash out of the back. This is just one way trash is placed into the landfill.
Other ways are:
Residential Trucks
Roll Off Trucks 
Photo from: www.dumpsters.com
Dump Trucks
There are other ways trash is transported to landfills, but the four above are the main ways. For instance, trains bring in trash to certain landfills, but these are the most common ways trash is brought to the landfills.
How Landfills are Started
First, the land is purchased by a company or the land is owned by a government. A company could also collaborate with a city government and form a partnership. When the land is acquired, usually in the country, a hole is dug. It is usually a deep hole as much as 500 feet depending on the capacity of said landfill.
First: The Liner
Photo from: www.xrgeomembranes.com
The liner is a series of strong plastic sheets that are rolled on the bottom and sides of the landfill. This prevents leachate (trash juice) from coming in contact with the ground and going into the groundwater. This practice started in the 1980's after EPA regulations required it. Before the plastic liners, many engineers used compacted clay, but it was ineffective.
Second: Drainage systems
Photo from: wteinternational.com
Next comes the drainage system. This allows runoff of leachate to be pumped from the bottom of the landfill and into containment zones or tanks.
The top image is an evaporation lake used to keep landfill water in a contained area. The bottom image is a landfill leachate tank. The tank is drained into tanker trucks and transported away to water treatment plants. These are very important parts of the landfill and helps keep our water safe from deadly chemicals.
Third: First Layer of gravel and dirt
Before the first load of trash is placed into the landfill, a layer of gravel is placed over the drainage system followed by a layer of dirt. After this, they will start placing the trash is cells. After a cell is laid, they will place a layer of dirt over it and then start to fill another cell. This allows the landfill to utilize the space of the landfill more effectively.
Methane Capture System
When the landfill fills up with trash, methane is produced as the garbage is broken down. Since the landfill is a contained system, methane can build up fairly quickly and if left unchecked, it can cause nasty consequences. Methane is a deadly greenhouse gas, even worse than carbon dioxide. So, they place pipes that pump the methane into a centralized place where is placed for fuels or just burned off. Bigger landfills can utilize the methane for turning into liquid natural or compressed natural gas. The other method is just burning it off and turning the methane into carbon dioxide.
End of Life of a Landfill
After a landfill is full. Usually that is between 30 and 50 years. Some are longer depending on the size of the service area. When they begin the capping process, they place a large tarp over the mound. This traps in the methane and allows the methane collection to deal with the methane. Next, they add a few layers of dirt over it. Trees and other large plants are forbidden from growing on the capped landfill, because the roots can destabilize the landfill and allow methane and leachate to escape.
30 years after the landfill is capped, it is deemed safe and sometimes it can be built upon. One such landfill in Massachusetts is used as a solar farm.
Sometimes homes can be built on old landfills, but they have special building codes. This is not common. Most times, the mountain of trash is just allowed to be what it is.
I hope this brought you some insight into landfills and how they impact our lives. Without landfills, we would be living in filth. In later blogs, I will show you how garbage was processed in the past. I will also talk about transfer stations and trash burners.
Thank you for reading and feel free to leave comments, question, and suggestions for future posts.
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