Where does our trash go?

Have you ever wondered what happens to your garbage after it leaves your curb or the back of your truck? Most of us rarely think about our waste once it leaves our hands, but understanding how landfills work can help us make better choices about what we throw away.

When your trash gets to the landfill, it enters a complex system designed to contain waste safely. Modern landfills aren't just giant holes in the ground. They're divided into sections called "cells" that are prepared before any trash arrives. Layers of clay and thick plastic sheets create a barrier lining each cell. This barrier is crucial because it prevents harmful liquids from seeping into the soil and groundwater.

As trucks dump trash into these cells, heavy machines called compactors crush the garbage to save space. Workers cover the compressed waste with a layer of soil at the end of each day to reduce odors and keep pests away. This process continues as the cell slowly fills up.

Many people think landfills work like giant compost piles, but they're actually quite the opposite. In a compost pile, materials break down quickly with plenty of air, water, and helpful microorganisms. Tight packing in landfills prevents much oxygen or water from entering and slows down decomposition dramatically.

A banana peel that might decompose in weeks in your backyard compost could last decades in a landfill. Plastic bottles might take 450 years to break down, and glass could last for over a million years. Even a newspaper, which decomposes quickly in a compost pile, can still be readable after 50 years in a landfill.

Modern landfill operators have developed methods to speed up decomposition where possible. Some landfills use "bioreactor" technology that carefully adds moisture to the waste. Others install pipes to collect the methane gas produced by decomposing materials. This gas can be burned to generate electricity instead of escaping into the atmosphere where it would contribute to climate change. Despite these innovations, complete decomposition in landfills still takes centuries.

When a cell reaches capacity, it is "capped" with multiple layers. First comes a layer of clay, followed by a synthetic liner similar to the one at the bottom. Above this, workers add drainage materials, more soil, and finally grass or other plants. This cap serves several purposes: it prevents rainwater from filtering through the trash, contains odors, and makes the land usable again for almost any purpose.

Despite all these precautions, landfills still pose some risks to nearby water sources. The liquid that forms when rainwater filters through waste is called leachate, and it can contain harmful chemicals. Modern landfills have leachate collection systems that pump this liquid out for treatment. They also have groundwater monitoring wells positioned around the perimeter to detect any contamination quickly.

Our approach to landfills has changed over time. Older dumps had few regulations and no protective liners, leading to serious pollution problems and reputations. Today's regulations require careful site selection, proper liners, leachate management, and long-term monitoring even after a landfill closes.

As landfill space becomes more limited and expensive, many communities are focusing on reducing waste through recycling, composting, and reuse programs. The best solution to our waste challenges might not be better landfills, but creating less trash in the first place.

Locally, there are many trash diversion programs. Mat-Su's Solid Waste Division rescues books and offers them cheaply. You can walk away with an entire box full of books you selected from the multiple rooms of children's books, bestsellers, hardbacks, history, cookbooks, and more for less than the cost of a single paperback book in a store. The Borough also allows people to pick up rescued hazardous waste for free such as partially used containers of primer, paint, stripper, pesticides, and more. This allows more full use before final disposal.

Christian M. Hartley is a 40-year Alaskan resident with over 25 years of public safety experience and public service. He runs a freelance business, Big Lake Writer, from home in Big Lake that he shares with his wife of 19 years and their three teenage sons.