Image via WikipediaMost people think of landfills as stinking mounds of rotting garbage. They are typically thought of as necessary evils. While it is true that recycling and reducing waste is important to the future of our planet, the evils of landfills can be mitigated by using them to provide energy. While this doesn't eliminate waste, it at least puts waste to good use.
In a landfill trash is typically buried. Many modern landfills are lined to prevent wastes from seeping to the groundwater and polluting it. Organic materials in the buried garbage are broken down by a process known as anaerobic digestion. Anaerobic means "without oxygen". Since the trash is buried, oxygen cannot easily reach it. As a result, bacteria that can metabolize organic materials without oxygen digest it. One of the by products of this process is landfill gas. Landfill gas is composed of over 50% methane.
Methane gas is also known as swamp gas because of its bad odor. Methane escaping from the ground is the major cause of bad odor associated with landfills. This escaping methane is also dangerous to our environment. Methane is a very potent greenhouse gas. It is a much stronger contributor to global warming than carbon dioxide. Fortunately, methane can also be useful. The natural gas that we use to generate electricity and to heat our homes is composed mostly of methane.
Landfill gas recovery, is a process of capturing the gas generated by anaerobic digestion. This gas is captured to be used or to simply be burned in order to prevent the methane from contributing to global warming. The process for capturing the landfill gas is very similar to the process for capturing natural gas from the earth. A well is drilled into the landfill and pipes are inserted to capture and direct the gas.
The captured landfill gas contains a great deal of water as well as numerous sulfur compounds. These need to be removed if the gas is going to be used to provide energy. The water reduces the efficiency of the gas for creating energy. The sulfur compounds can contribute to smog and pollution when the gas is burned. Once these are removed, the landfill gas can be used to generate electricity.
There are a number of ways in which landfill gas can be used to generate electricity. One common method is to burn the gas to heat water. The heated water is then used to drive the turbines for generating electricity. Another method is to use it in place of natural gas. In Ohio, several Rumpke landfills use landfill gas recovery systems to capture, treat and then sell the gas to Duke Energy. Duke Energy then pipes this gas to its natural gas users.
Landfills can be a danger to our environment but in many ways they are necessary evils. By using landfill gas recovery, landfills can help contribute to our world's energy needs while keeping dangerous greenhouse gases out of the atmosphere. In many ways, this makes landfills necessary but maybe just a little less evil.
John Z. Franklin is a graduate Colorado State University were he earned a degree in Environmental Science. He also earned his JD at Harvard Law School. He is a freelance writer interested in educating the public about the many simple energy and easy to adopt energy efficiency behaviors. Mr. Franklin is a co-owner of Air and Gas Systems, Inc. franklinjohn@gmail.com
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