San Francisco to Recycle Its Pet Poop for Cheap Energy

Pet poop power: what a concept! It’s already being tried in the Bay Area of northern California, and it sounds like a smart idea, considering that the latest National Pet Owners Survey shows that 63%, or 71.1 million U.S. homes, own a pet that produces poop. That’s 38.4 million households with at least one cat and 44.8 million households with one or more dogs. The grand total number of U.S. pets is 88.3 million cats and 74.8 million dogs.

Just think of all the poop engendered every year by each of these cats and dogs, just laying around untapped. According to scientist Will Brinton, a leading authority on garbage, dogs and cats are responsible for 10 million tons of waste a year. Where is it all going? Not to the right places, unfortunately.

San Francisco, always on the cutting edge of progress, is now looking into recycled pet poop to provide heat, cook meals and even generate electricity. An astounding 4% of its total landfill trash consists of pet feces. The City by the Bay hopes to stop sending trash to its landfills by 2020, and one way to do that is to creatively use recycled cat and dog feces. Right now it’s still in the experimental stages, but the idea is to convert pet poop into methane, a potentially harmful greenhouse gas, which can then be used for fuel.

The reality is that a big portion of pet poop ends up in landfills, wrapped in plastic bags by pet owners, and sits there indefinitely without degrading. Some is just left where it’s deposited, on the ground, and it can end up in the water supply or any nearby bodies of water after it dissolves. Other animal waste is picked up and deposited in compost bins, which is a bad idea because it contains pathogens. For example, a parasite attacking California sea otters comes exclusively from cat poop. Dog waste has affected the water quality of once-pristine waters like Lake Tahoe.

In San Francisco, Norcal Waste, which picks up trash in the city, is in the process of discovering how to creatively use pet poop for energy like electricity, natural gas and fuel. The first step is to encourage dog walkers to throw poop into biodegradable bags and carts in dog parks. Then Norcal will collect it, throw it into a methane digester, and two weeks later, the methane is ready to use as a power source, just like natural gas. A year’s worth of recycled pet poop from a city park can potentially produce as much as 50 gallons of fuel.

Methane, or biomass, digesters are simple machines that slowly convert animal waste to methane using bacteria (it takes about two weeks). This is a great idea for generating more power and saving money for cities and towns. And it’s already being used by a few American dairy farmers, in Europe and in some developing countries. India uses methane digesters to convert cow manure, one pound of which is enough to supply energy for family meals.

On an individual basis, methane digesters aren’t practical because most homes don’t produce enough pet poop and other organic waste to justify their use. So a good idea for pet owners in rural areas would be to get together and collectively run methane digesters. Or, if you happen to run a pet sanctuary or shelter or you just have a lot of pets, a methane digester could be a nifty way to convert free poop into free power.

All animal waste eventually degrades into methane, which is even worse than carbon dioxide for the environment and contributes significantly to global warming. So if pet poop can be used for the good, as an alternative energy source, then more green power to Planet Earth and all its inhabitants.

www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/02/21/MNGUIHBUPP1.DTL&hw=norcal+pet+waste&sn=001&sc=1000