Methane is a particularly powerful greenhouse gas. The good news is that methane doesn’t last very long in the atmosphere: it has a half-life of nine years, while carbon dioxide lasts 27 years. The bad news is that during the first 20 years in the atmosphere, methane is such a powerful greenhouse gas that a single molecule of methane warms as much as 84 molecules of carbon. Rather than seeing this as a problem, think of it as a lever. If we can focus on reducing methane immediately, we will see an immediate impact on global warming.
If we can focus on reducing methane immediately, we will see an immediate impact on global warming
Methane is naturally emitted by wetlands, oceans and termites, but the largest amount of methane comes from human activities. Land conversion, for example in South America where forests are converted to agriculture, creates a large amount of methane. Growing rice in flooded paddies in Asia also releases methane. The largest sources of methane in North America are oil and natural gas activities, cow burps (scientifically known as eructation from enteric fermentation) and poorly decomposing material in landfills. In North America 18% of methane comes from landfills.
Some landfills keep methane out of the atmosphere by installing pipes to collect it and burning it off at the surface (surprisingly, this “flaring” is better for the atmosphere than letting methane escape). The Vernon landfill currently flares methane. Landfills that produce large quantities can actually use the methane to generate electricity or natural gas. Both Salmon Arm and the Glenmore Landfill in Kelowna sell to Fortis BC. In the south Okanagan neither of these techniques are cost effective: our landfills are small and our dry climate further reduces methane production.
What can we do about the methane escaping from smaller landfills in the Okanagan? RDOS has been working with Sperling Hansen Associates on a pilot project at the Campbell Mountain Landfill outside Penticton. The goal was to develop a way to prevent the landfill from releasing methane into the atmosphere.
The pilot project is using a product of waste water treatment (mixed with local wood chips and sand for aeration) to cover parts of the landfill. For the project, they measured the amount of methane emerging from covered and uncovered parts: the landfill areas covered by the mixture are absorbing nearly 75% of the methane. These covered areas could eventually be covered in grasses. The Seven Mile Landfill biocover project, on the northern tip of Vancouver Island, is so successful they generate excess carbon credits.
What are the “waste water treatment products”? At the wastewater treatment plant, bacteria are
used to break down (or compost) sludge (human feces and toilet paper). Heat is used to kill any pathogens. Then the material is aged (like a good wine) for 10 to 20 years. At this point the material is carbon-rich soil: there’s no germs, no smell and it doesn’t attract pests. Metro Vancouver has this fine aged soil in abundance. They normally ship it for disposal to Alberta and were happy to make it available to RDOS. The Campbell Mountain pilot project already uses local wood chips. Eventually they could also use local waste water treatment products.
This is great news for Penticton and the south Okanagan: moving forward the garbage we send to landfills will emit less methane. It is also good news for small landfills everywhere: in regions where landfills don’t produce enough methane for electricity generation, or flaring, we can at least protect the atmosphere from methane release.
Missed last week’s column?
Kristy Dyer has a background in art and physics and consulted for Silicon Valley clean energy firms before moving (happily!) to sunny Penticton. Comments to Kristy.Dyer+BP@gmail.com
Kristy’s articles are archived at teaspoonenergy.blogspot.com