Saturday, March 10, 2007

Deep doo doo. Literally!

Boy, those Albertans really know how to take the lead in GHG reductions. Worried about your dog's contribution to global warming? Energy Solutions Alberta has a suggestion - compost his/her - um - emissions.

The idea here is that any organic material that is landfilled (e.g. doggie doo) produces methane - a very potent greenhouse gas. Therefore, the site says, compost the waste in your backyard; the implication being that doing so will reduce the production of methane.

However, you can't just throw Fido's poo into your regular backyard composter. Any pathogens present would not be destroyed, and then you couldn't use the compost on your tomatoes (ew!). So, they recommend products such as the Doggie Dooley Pet Waste Digester System.

Automatically reduces pet wastes to a ground absorbing liquid that is harmless to pets, wildlife and the environment - will not damage grass or shrubs

Sounds good, right? Save space in landfill - check; keep doggie doo out of parks and off beaches - check; reduce methane production - um... really??? These 'composters' seem to be digesters which probably use anaerobic bacteria to break down the waste. Another site selling the same product says:

Pet Waste Digester is [...] like a stomach, fresh digesting enzymes are applied to the buried green plastic pyramid that neutralizes pathogens that thrive in foul anaerobic conditions.

In other words, it's a small septic tank for your dog. According to wikipedia, septic tanks "ultimately generate carbon dioxide and methane, both of which are known greenhouse gases." The web site for another product called the Doggie Dooley even says "Works like a home septic system".

The same Energy Solutions Alberta article notes that San Francisco is looking at using dog poo as a source of renewable energy - by capturing the methane produced when the waste is digested. Now that sounds like a project that could have some benefits. If you can capture the methane, you can use it for fuel, thus reducing reliance on fossil fuels. However, I imagine that it's hard to capture the methane from a backyard digester.

However, Albertans are not the only ones concerned about doggie doo and what to do with it. The National Capital Commission has a paper on line that describes a pilot composting project. However, the methods they are describing seem to be aerobic, and so may actually reduce methane emissions (although it's not mentioned as a factor in this paper).

So, go ahead and compost that doggie doo - but don't expect to be able to sell carbon offset credits for your efforts.

Now, lest you think I'm just bashing Alberta or the Energy Solutions Alberta web site, they do have lots of other energy-saving tips and information. And this story is really neat too: The SolarBee: A Solar Sci-fi Fantasy

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