Managing landfill gases

Landfill gas (LFG) is a mixture of gases produced by the decomposition of organic waste in landfills. The main components of LFG are methane (CH4) and carbon dioxide (CO2), which typically make up 45-60% and 40-60% of the gas by volume, respectively. LFG also contains smaller amounts of other gases, such as nitrogen, oxygen, ammonia, sulfides, hydrogen, and non-methane organic compounds (NMOCs).

LFG is produced when bacteria break down organic waste in the absence of oxygen. This process, called anaerobic digestion, occurs naturally in landfills. The amount of LFG produced depends on the type and amount of waste in the landfill, the moisture content and temperature of the waste, and the age of the landfill.

LFG can be a hazard to human health and the environment. Methane is a potent greenhouse gas, meaning that it traps heat in the atmosphere. Methane is also flammable, and high concentrations of methane in the air can create an explosion hazard. Other gases in LFG, such as ammonia and hydrogen sulfide, can be toxic and can cause a variety of health problems, including respiratory problems, eye irritation, and nausea.

LFG can also migrate through the soil and collect in nearby buildings, where it can displace oxygen and create a health hazard. Additionally, LFG can damage vegetation and pollute groundwater.

There are a number of ways to manage LFG, including:

• LFG collection and utilization: LFG can be collected and used to generate electricity, produce heat, or fuel vehicles. This helps to reduce greenhouse gas emissions and other environmental impacts.
• LFG flaring: LFG can be flared to destroy the methane and other hazardous gases. However, flaring also releases CO2 into the atmosphere, which is a greenhouse gas.
• LFG barrier systems: LFG barrier systems can be installed to prevent LFG from migrating through the soil and collecting in nearby buildings.

In recent years, there has been a growing interest in using LFG as a source of renewable energy. LFG-to-energy projects are now operating in many countries around the world.