Ecology And Environment

How could Refuse Landfills be used to Produce Gas for Energy



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East of Palo Alto, the college town associated with Stanford and Silicon Valley, is Byxbee Park, a post-modern park built on bay fill, on compacted garbage. The park makes no attempt to disguise its origins, though the garbage is sealed away.

Among its many examples of environmental art, Byxbee features an eternal flame, humorously named the Keyhole, where the methane of the landfill burns off. The flame burns night and day, on the methane naturally generated by garbage decaying in the absence of oxygen.

When wet organic garbage rots in anaerobic conditions, it produces methane. There is no question about how refuse landfills could be used to produce gas for energy. It happens naturally, though the methane is a bit dirty, tainted with carbon dioxide, water vapor, and sulfur compounds. The question is how to harness the methane that landfills generate to produce useful, economical, reliable energy.

Right now, the unused methane that escapes from landfills contributes to climate change, and to photochemical smog. In China, though, small farm biogas digesters already reduce pollution and climate change. Why don’t we use biogas from landfills to meet some of our huge energy needs?

Problems bringing biogas online

One reason biogas is not used on a large scale is that sulfur compounds in the gas corrode machinery. Biogas can be cleaned up and made usable, but current processes raise the price of the product.

The natural gas in use now is basically fossil methane, and it’s cheap. The fracking process has unlocked vast stores of natural gas once locked in rock. The low prices this abundance has brought naturally discourage the search for substitutes.

Progress with biogas

Here and there though, animal manure is already used as a source of power. Anti-pollution regulations encourage large livestock operations to use biogas digesters to reduce waste and harness energy. Large hog-farming and cow-finishing operations already see financial benefits from biogas digesters.

In 2010, there were at least 160 biogas methane digesting operations producing electricity on livestock farms, according to the Natural Resources Defense Council.

As time goes by, producers of energy from biogas will get better at it. Increased production is likely to bring economies of scale. The lessons learned on livestock farms will eventually translate to municipal plants. One of the sources of the energy of the future is likely to come from the landfills of the past.

Byxbee Park is popular with bird watchers, joggers, and strollers. Its waterways are a stop on the Pacific Flyway, and some of its mounds have been colonized by burrowing owls. The old dump is covered with blooming mustard in spring, and cattails clatter in the salt marshes. The sculptures here remember their roots. It’s not entirely beautiful yet, not always, but it will be.

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More about this author: Janet Grischy

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  • InfoBoxCallToAction ActionArrowhttp://www.weeklywalker.com/Walks%20by%20county/Santa%20Clara%20County/Byxbeepark_a%20walk%20th%20envir.htm
  • InfoBoxCallToAction ActionArrowhttp://www.helium.com/items/428508-natural-gas-processing-sweetening
  • InfoBoxCallToAction ActionArrowhttp://www.nrdc.org/energy/renewables/biogas.asp