From Your Trash Can to the Landfill: What Really Happens to Your Garbage

Every trash day, when your waste is placed in the can at the end of your driveway to be picked up by Ryland Environmental, it’s easy for you to think of that as the end of the road for that waste. In reality though, that trash is just beginning a long, carefully-managed process inside a modern landfill that is designed to protect soil, groundwater, and the air from pollution. Modern landfills are highly engineered systems that layer liners, pipes, pumps, and soil in a specific way so your garbage can break down as safely as possible over many decades.​ In this blog, we’re going to go over some of the basics to show you how modern landfills are actually more like modern marvels.

The Basics

When your trash leaves the curb, it is loaded into a compactor truck that squeezes the bags to save space and reduce the number of trips to the disposal site. Once the truck is full, it drives to a landfill or sometimes to a transfer station, where waste from many trucks is combined and then hauled in larger loads to a regional landfill. At the landfill, trucks drive up to a specific working area called the “working face” and tip the trash onto the ground to start the next stage of the process.​

Heavy equipment such as bulldozers and compactors immediately spread the waste into thin layers and drive over it multiple times to press out air pockets. Compressing the trash makes the best use of limited landfill space and also helps stabilize the pile so it does not shift or collapse. At the end of the day, that fresh layer of waste is covered with soil or another approved cover material to control smells, keep trash from blowing away, and discourage animals and insects from visiting.​ This package of waste surrounded by soil is called a “cell”.

Layers Under a Landfill

To really understand how a landfill works, picture a layered cake built upside‑down in the ground. At the very bottom is natural soil and groundwater that must be protected. On top of that, engineers build several man‑made layers that act as barriers and plumbing so liquids and gases can be controlled instead of leaking into the environment. This structure is what makes a sanitary landfill different from an old‑fashioned open dump.​

A typical modern landfill has these main parts working together:

• A bottom liner system that separates trash and contaminated liquid from groundwater.

• Waste “cells” where trash is placed, compacted, and covered.

• A leachate (contaminated liquid) collection system and separate stormwater drainage system.

• A gas collection system for methane and other landfill gases.

• A final cover or “cap” that seals the landfill when it is full.​

Each piece is designed to handle a specific problem: keeping rainwater out of the waste, keeping leachate in pipes instead of the ground, and keeping gases under control rather than letting them escape into the air. Let’s go over how each of these parts work.

The Bottom Liner: Keeping Trash Away from Groundwater

The most important protective layer is the bottom liner, which acts like a giant, engineered bathtub under the waste. First, a thick layer of special clay is compacted to make it very dense and hard for water to pass through. On top of that clay, workers install a plastic liner—often made from high‑density polyethylene (HDPE)—that is flexible but very tough, and seams are welded together so it forms one continuous, watertight sheet.​

This double barrier greatly slows or stops liquid from moving down into the natural ground. If the landfill is very large or located in a sensitive area, regulations may require even more protection, such as a secondary liner and an extra collection layer between the two liners. These backup systems are there in case the primary liner ever develops a leak, so any escaping liquid can still be captured and monitored before it reaches the environment.​

Leachate: What It Is and How It Is Managed?

Leachate is the liquid that forms when water moves through the trash and picks up dissolved materials, and it is one of the biggest environmental concerns in landfill design. Rain and snow that land on the landfill, plus moisture from the waste itself, seep downward through food scraps, paper, fabric, and other materials. Along the way, the water picks up organic chemicals, metals, and other contaminants.​

To prevent this liquid from pooling at the bottom and eating through liners, landfills install a leachate collection system on top of the liner. This system usually includes:

• A drainage layer made of gravel, sand, or other coarse material that lets liquid flow easily.

• Perforated pipes laid on a slope so gravity can carry leachate to collection points.

• Sumps or ponds where leachate is stored temporarily before treatment.​

Once collected, leachate is pumped out and treated, often at an on‑site treatment plant or a municipal wastewater facility. It may be filtered, biologically treated, and chemically adjusted to remove or reduce contaminants before it is released or reused. Operators regularly test the leachate for chemical and biological indicators to make sure the system is working and to catch any changes in pollution levels early.​

Managing Methane: Turning a Problem Into a Resource

Inside a landfill, buried waste breaks down slowly over many years, mostly without oxygen because the trash is compressed and covered. This kind of oxygen‑free (anaerobic) breakdown is driven by bacteria that feed on food scraps, yard waste, paper, and other organic materials. As they work, they produce landfill gas—typically around half methane and half carbon dioxide, plus small amounts of other gases.​

Methane matters for two big reasons. First, it is a powerful greenhouse gas, much stronger than carbon dioxide at trapping heat in the atmosphere. Second, it is also a fuel—the main component of natural gas—so it can be captured and used to make energy instead of being wasted. If landfill gas is not collected, it can escape through the surface, contribute to climate change, and create odors or even explosion risks if it builds up in enclosed spaces.​

To control landfill gas, operators install a gas collection system made of wells and pipes inside the waste mass. Vertical wells are drilled down into the trash and fitted with perforated pipes, and sometimes horizontal pipes are added between layers as the landfill rises. These pipes are connected to a vacuum system that gently sucks gas out of the landfill and carries it through a header line to a treatment area.​

Once collected, gas can be handled in two main ways. Some sites flare it, burning the methane at high temperatures to convert it into carbon dioxide and water, which reduces its climate impact and destroys many odor‑causing compounds. Other landfills clean and use the gas in engines, turbines, or boilers to generate electricity or heat, or upgrade it to pipeline‑quality renewable natural gas that can be used like regular natural gas. In all cases, careful monitoring helps keep gas flows steady and prevents unwanted leaks.​

Final Cover and Long‑Term Care

When a landfill or section of a landfill reaches its planned capacity, it is not simply abandoned; it is sealed and monitored for many years. The top is graded to shed water and then covered with a final cap made from layers of clay or plastic, drainage materials, soil, and vegetation. This cap keeps rainwater out, limits gas escaping through the surface, and provides a stable, plant‑covered landscape that blends better with the surrounding area.​

Even after closure, operators must monitor the site for upwards of 30 years. They use a number of strategies to ensure that the surrounding area is protected, such as checking groundwater wells around the landfill for any sign of contamination, measuring gas levels and adjusting the gas collection system as needed, and inspecting the cover for erosion, cracks, or settlement and making repairs.​

These long‑term steps help ensure that the buried waste remains isolated and that future generations are not left with unexpected pollution problems.

Why Your Everyday Choices Still Matter

Even with all this engineering, landfills still require land, energy, and constant management, so what goes into them really matters. Reducing waste at the source—by buying only what you need, reusing items, and avoiding unnecessary packaging—helps cut the total amount of trash that must be buried. Recycling paper, cardboard, metal, glass, and certain plastics, and keeping hazardous items (such as paints, batteries, and motor oil) out of regular trash, also makes landfills safer and more efficient for ourselves and for future generations.