Views:193 Author:Site Editor Publish Time: 2019-10-15 Origin:Site
What is a Landfill
Maybe you feel a bit guilty as you roll your container to the curb. After all, despite any recycling or composting you might do, some items still must go to the landfill—and landfills have a reputation for harming the environment. But it turns out that image doesn’t always match up with the way modern landfills work.
From managing gas emissions to monitoring groundwater, modern landfill science allows today’s waste collection facilities to minimize their ecological impact as much as possible.
In the past, we tossed our waste into open dumps. These sites were not monitored and few steps were taken to separate waste from the surrounding environment. This meant it was easy for toxic chemicals and gases to contaminate the nearby air, soil and groundwater. These areas also acted as breeding grounds for mosquitoes and other disease-carrying pests. Many people still associate that dirty image with landfills. But today, nearly all landfills are sanitary landfills. The open dumps of the past are rare, except in cases of illegal dumping.
A modern landfill is a highly engineered and regulated pit in the ground that is divided into “cells”. Each cell is carefully engineered to maximise compaction and eliminate potential environmental impacts.
Certain landfills are licensed for particular waste types, for example not all landfills accept putrescible waste and some are licensed to accept hazardous material like asbestos, while others are not.
The odours produced by landfills are the result of gases produced by decomposing waste. At Cleanaway, we manage landfill odour through a variety of proactive measures, including:
· Maintaining adequate soil cover at the active landfill cell.
· Daily site inspections, which include the site boundaries and landfill surface to quickly identify and resolve any issues.
· Installing gas wells to turn landfill gas into energy.
· Utilising portable gas monitors to track air quality.
· Shutting down the site when extreme weather appears, such as strong winds.
To put it simply, sanitary landfills operate by layering waste in a large hole. The deepest spots can be up to 500 feet into the ground, like Puente Hills, where a third of Los Angeles County’s garbage is sent. As materials decompose, landfill gas experts continuously monitor groundwater to detect any leakage.
Let’s dig into how each layer works to keep waste from affecting the environment as it safely decomposes.
Layer 1: The Liner System
The bottom of a modern landfill is typically lined with compacted clay dense enough to prevent liquids from penetrating it. On top of the clay, landfill engineers install a liner made of high-density plastic for added protection.
Layer 2: The Drainage System
Some waste produces liquid as it decomposes. And as rain and snow filter through a landfill, it can carry other contaminants to the bottom. Perforated pipes are installed on top of the liner to collect these liquids—known as leachate—and funnel them to treatment facilities, either onsite or at wastewater treatment plants.
Layer 3: The Gas Collection System
Waste naturally produces methane as it decomposes and when methane is released into the atmosphere, it contributes to global warming. But methane is also the main component of natural gas. Modern landfills work to turn methane into power using gas extraction wells that pipe it to treatment areas and then to plants that will turn it into electricity or other forms of energy.
Layer 4: The Trash Itself
In the main area of the landfill, trash is delivered and then compacted to take up less room. Every day, the new trash is covered with a layer of dirt which helps contain odors and deter pests.