All waste eventually breaks down, even if it takes thousands of years. Most of the municipal waste stream today breaks down far more rapidly, especially considering up to half of a general landfill’s content can be food and yard waste combined. These organic materials produce a lot of gas as they break down, but even styrofoam and plastic products will eventually release gases as they decompose. These combined gases are referred to as landfill gas, or LFG. LFG has changed from a secondary nuisance to a primary product thanks to changing perceptions and new demands for power. Understanding the potential applications and risks of uncontrolled landfill gas will make it clear while capping and pressure management systems are so important.
Generating Power
Since it is created from the natural decomposition of waste that would break down no matter what, LFG is considered a renewable power source with minimal environmental impact. That makes it ideal as a power source since there is a constant stream of waste filling landfills around the country. LFG production can be predicted and planned around since it tends to follow a specific pattern as each capped cell ages. Methane is a potent source of power when combusted, which also destroys it, so it is not released into the atmosphere. Only a small amount of carbon dioxide is produced during this form of power generation, making it a good choice when compared to other types of waste incineration for power. The other gases mixed in with the methane can be burned without consequence or emissions in most cases as well, making power generation one of the best uses for LFG. It can generate a profit to cover the costs of maintenance after a landfill has closed and is no longer receiving new waste. By the time the LFG coming from a capped cell tapers off, its need for maintenance will be reduced as well.
Direct Heating and Cooking
With some additional processing to separate out more volatile gases, methane from landfills can be used for direct heating and cooking applications as well. Most cooking uses blend the methane with other gases to produce less odor and soot, but it’s often used on its own for direct heating in both commercial and residential settings. Food processing and packaging, in particular, can benefit from a steady and low-cost source of heating for pressure and steam sanitization equipment. Boiler systems allow for double generation of both valuable heat and power from the same LFG source.
Industrial Purposes
Whether it’s used to power a boiler system, power generation unit, or direct heating like kilns and glass furnaces, LFG has many industrial uses. It’s also a good choice for local power production for businesses since the reclaimed land of the capped landfill is an ideal place for locating new development. Many states and counties are developing projects for closed landfills that pair low-cost power and gas services with affordable property leases to attract industrial development to the area. Other industries already taking advantage of existing LFG supplies include:
- Pharmaceutical manufacturing
- Cement block and brick production
- Chemical treatment and processing
- Automotive manufacturing and similar steel-reliant industries
- Wastewater treatment
- Paper mills
- Institutional facilities like hospitals and prisons.
Reducing Non-Renewable Resource Use
Since LFG is a renewable gas that will be generated by waste no matter how it’s handled, it has the potential to protect the environment by reducing the use of non-renewable resources like propane and coal. Every BTU of heat or kW of power generated through the use of LFG reduces the amount of drilling or mining needed to produce other fuel sources. Unlike other renewable power sources like wood-fired power plants or trash incinerators, there is little additional impact on the environment since landfills are needed regardless of the final use of the waste. There is also no conflict between waste reduction measures like recycling and trash diversion and gas production since there is always some amount of waste that ends up needing landfill consignment.
Odor Control
Odor control was the first cause for gas control at the earliest forms of the sanitary landfill design. As scientists developed safe and reliable ways to keep odor under control for the benefit of nearby residents, they also discovered the ammonia and methane contributing to the unpleasant smell had other uses. Methane can be a fire or explosion hazard if contained without appropriate release and use. Piping it to a processing facility or a direct use application takes care of odor and fire risk at the same time, keeping the landfill from becoming a safety hazard as time goes by.
Emissions and Safety
According to the Environmental Protection Agency, “methane emissions from MSW landfills in 2019 were approximately equivalent to the greenhouse gas (GHG) emissions from more than 21.6 million passenger vehicles driven for one year or the CO2 emissions from nearly 12.0 million homes’ energy use for one year.” Re-routing all that released methane has the potential to dramatically lower total GHG emissions in the US. When combining that benefit with the ability to reduce the use of carbon dioxide and nitrous oxide-producing fuels, the total protection to the environment is increased further. Furthermore, landfills with active or passive gas control systems are much safer for nearby residents since exposure to methane and other potentially irritating gases is reduced for years to come. Methane is explosive at concentrations of just 5% to 15% of total air volume, so keeping it in a controlled system is a safer choice than allowing it to flow uncontrolled around a landfill site.
Don’t let methane and other valuable gases go to waste when there are multiple technologies available today for collecting them instead. Old landfill cells, with open methane wells can still be adapted and pressurized with the right cover retrofit to start harvesting gas. Choose BTL Liners products for both newly capped cells and renovations of older landfills that still have good gas volume.
