Landfill gas is created by organic matter decomposing in landfills. It’s nasty stuff, almost entirely methane and carbon dioxide. Methane is particular is a potent greenhouse gas. When released, it traps heat in the atmosphere. In the past, landfills would either do nothing or flare the gas. However, if captured, landfill gas becomes renewable energy and an income stream. A problem then becomes an asset.
The gas can generate electricity, be used as thermal energy in heating, directly substitute for another gas in industrial applications, or be refined to create natural gas.
In a related process, gases produced by animal manure can also be turned into usable gas. Karachi plans to run 200 buses on bio-methane produced by water buffalo poop.
The project will prevent about 3,200 tonnes of cow manure entering the ocean daily by converting it into energy and fertiliser at a biogas plant, and will save more than 50,000 gallons of fresh water now used to wash that waste into the bay, Aslam said.
Advanced Disposal explains how they use landfill gas.
Landfill gas collection systems are how modern landfills deal with gases created within the waste.
Here’s how the process to convert this valuable resource to energy works: as landfill cells are filled with waste, methane gas, a byproduct of any decomposing material, is collected from within the waste through a system of vertical wells and pipelines and directed to a separate on-site treatment facility. The treated landfill gas is either pumped off site to a manufacturer near the landfill to supplement or replace their natural gas usage or is used to generate electricity right at the landfill that is delivered to the electrical grid.
Another benefit of the destruction or utilization of this landfill gas is that it prevents the raw methane in the gas from escaping into the atmosphere as a greenhouse gas.