How does a landfill work?

Summary

This educational video explores the intricate workings of a landfill cell, from its construction to its closure. It explains the purpose of various layers, including clay and a flexible membrane liner, designed to prevent leachate and protect the environment. The script delves into leachate collection, gas collection systems, and the process of sealing a landfill cell. It concludes with the transformation of a closed landfill into a grassy hill, highlighting the ongoing gas and leachate management post-closure.

Takeaways

• 🏗️ A landfill cell is a well-engineered hole in the ground used for burying trash.
• 🗓️ Landfills can have multiple cells, each named after the year of construction, like FYO2 for fiscal year 2002.
• 🚚 An active landfill cell is one that continues to receive trash from garbage trucks.
• 🔨 The construction of a landfill cell involves several layers including a clay base to prevent liquid permeation.
• 💧 A flexible membrane liner is placed on top of the clay to further seal the base and prevent leachate from escaping.
• 🚰 Round pipes within a layer of gravel collect leachate, which is any liquid that comes into contact with garbage.
• 🌱 The drainage layer, often made of shredded tires, allows liquids to flow while preventing garbage from settling.
• 🌿 A daily cover, usually soil or a spray-on material, is added to secure the garbage at the end of each day.
• 🔥 Gas collection pipes are installed to collect methane and other gases, which are then flared or treated to reduce environmental impact.
• 🌳 Once a cell is full and closed, it is covered with soil and seeds are planted to allow grass to grow, making it blend with the landscape.

Q & A

What is a landfill cell?

A landfill cell is a well-engineered hole in the ground where trash is buried. It is a part of a landfill that can have several cells over its lifespan.

How are landfill cells named in the Iowa City landfill?

Each landfill cell is named for the fiscal year it was constructed, such as FYO2 for a cell built in the fiscal year of 2002.

What does an active landfill cell represent?

An active landfill cell is one that is still receiving trash, where trash trucks empty their loads, and landfill operators work to compact and cover the garbage.

What is the purpose of the clay layer at the bottom of a landfill cell?

The clay layer is used to line the bottom of the cell and serves as a barrier to prevent liquids from flowing through, due to its low permeability.

What is the flexible membrane liner and its role in a landfill cell?

The flexible membrane liner is a well-engineered and strong plastic liner that seals the base of the landfill cell, working with the clay layer to keep leachate and garbage securely in place.

What is leachate and why is it collected?

Leachate is any liquid that comes into contact with garbage, also known as 'garbage juice'. It can contain toxic or hazardous materials and is collected to prevent harm to people, animals, and the environment.

How is leachate collected in a landfill cell?

Leachate is collected through round pipes surrounded by a layer of gravel, which are designed to prevent clogging and ensure proper collection and treatment of the liquid.

What is the purpose of the drainage layer made of shredded tires?

The drainage layer made of shredded tires prevents solid garbage from settling further while allowing liquids to flow freely down to the leachate collection pipes.

What is the daily cover in a landfill cell and why is it used?

The daily cover, usually a spray-on cover or dirt, is added to the garbage at the end of each day to secure it in place, reducing the potential for trash to blow around and lessening environmental impact.

What types of gases are collected in a landfill cell and why?

Landfill cells collect a mix of gases, primarily methane, which is a strong greenhouse gas. Collecting these gases helps mitigate their environmental impact.

How is the gas collected in a closed landfill cell utilized?

In a closed landfill cell, gas is collected through a network of horizontal pipes and transported to a flare, where it is burned at high temperatures, converting methane to carbon dioxide, a less potent greenhouse gas.

What happens to the top of a landfill cell once it is closed?

Once a landfill cell is closed, the protective layers such as the flexible membrane liner and clay are wrapped around the top, and a finished cover is added. Seed is planted on top, allowing grass to grow, making the area resemble a grassy hill.