What Happens to Trash in Landfills? — This Green Lifestyle

Ideally, anything that is considered hazardous waste (including paints, stains, poisons, etc.) would be properly disposed of or recycled locally. The EPA has numerous guidelines and regulations to help waste facilities as well as individuals understand hazardous waste and its disposal.

Usually, individuals can take household hazardous waste to local collection facilities for free, where the waste can then either be recycled or properly disposed of at an incinerator or hazardous waste landfill. Businesses or other generators of hazardous waste (such as hospitals) are likewise responsible for making sure their hazardous waste is properly recycled, disposed of, or treated.

You can learn more about hazardous waste management here.

What happens to trash at the landfill?

Whatever doesn’t get recycled, composted, incinerated, or polluted into the environment eventually makes its way to a landfill. But a landfill isn’t just a dump; it’s a carefully engineered facility that manages waste in order to minimize its environmental impact.

How landfill cells work

When trash, or MSW, arrives at a landfill, it is taken to a cell. A landfill usually has only one or two cells open at any one time in order to reduce impacts such as smell.

Once the trash has been dumped into the landfill, a trash compactor works to evenly spread the waste and compact it. This step not only reduces the volume of the trash, but also stabilizes the landfill. At the end of the day, all of the new trash gets covered by soil, debris, or some other approved cover in order to minimize smell, emissions, and animal activity.

Before a cell has filled up, excavation of the next cell begins so that there is no break in trash collection.

Methane gas collection

In the landfill, compacted trash slowly decomposes, releasing methane, a potent greenhouse gas. Food waste is the biggest driver of these emissions, not only because it decomposes rapidly but also because it is the single largest category of material that ends up in municipal landfills.

Modern landfills are designed to maximize the collection of methane gas, rather than allowing it all to escape into the atmosphere. Despite these efforts, landfills are responsible for 14.1% of human-related methane emissions.

Turning methane into electricity

Increasingly, landfills are collecting methane gas and turning it into electricity. The methane is “vacuumed” through a series of pipes, then filtered, processed, compressed, and finally combusted to generate usable energy for nearby cities.

But combustion is not the only process through which methane, otherwise known as biogas or landfill gas, can be repurposed. According to the US Department of Energy (DOE), with some additional conditioning, biogas can even be turned into a biofuel to power vehicles.

Burning off excess methane

Whether a landfill has a methane collection system and energy plant in place or not, excess methane is usually burned off to mitigate the amount of methane gas escaping into the atmosphere. While this method is imperfect, it converts most of the methane to CO2, which is a less potent greenhouse gas.

Leachate collection

In addition to methane gas, your trash also results in a byproduct known as leachate, a liquid that forms as water (i.e. rainwater) filters through the layers of waste in the landfill. Leachate contains hazardous chemicals as well as other kinds of suspended solids that can pose a serious risk to the environment as well as human health if not properly managed.

To prevent groundwater contamination, leachate is collected, contained, and/or treated, a process you can learn more about here.

Landfill closure and reclamation

When all of the cells in a landfill have been filled, the entire landfill has to be closed up. Landfill capping usually consists of adding layers of clay and soil to create a more or less impermeable layer above all of the compacted trash. Pipes are installed to collect methane gas, which is then either burned off or converted into electricity.

Because landfills are considered a “temporary” use of land, a closed landfill is usually reclaimed in one way or another. For example, closed landfills can be replanted with native species and turned into habitat for plants and wildlife. There are also examples of closed landfills being turned into soccer fields and parks.

Due to the possibility of landfills shifting over time, large-scale construction on top of landfills is typically avoided. However, there’s huge potential for other kinds of reclamation projects, including solar farms as well as agricultural fields for growing crops for biofuel or animal feed.

Regardless of how a closed landfill is reclaimed, it has to be closely monitored for 30 years to make sure waste and pollutants are not escaping into the surrounding environment.

Extending the lifespan of landfills

Despite the efforts to mitigate environmental impact, landfills remain a significant source of pollution, waste, and greenhouse gas emissions. Reducing the amount of waste sent to landfills not only reduces the environmental impact of waste, but also conserves natural resources and increases the lifespan of landfills. Given that landfill space is limited, this should not be overlooked.

Waste diversion practices include recycling, composting, and waste-to-energy technologies (such as combustion). Composting is something you can easily do at home or on a local scale, while recycling depends heavily on local infrastructure.

Luckily, national incentives and increased awareness are leading to more and more waste diversion, and many landfills have already been able to remain open long after closure was initially estimated. That said, we have a long way to go considering how much waste is sent to landfills every day.

To reduce the amount of trash you send to the landfill, consider the 7 R’s of waste management: Rethink, Refuse, Reduce, Reuse, Repair, Recycle, Rot.

How do you reduce your trash? Share your tips in the comments below!