The future: Energy produced by pet poop?

Animal feces make up nearly four percent of San Francisco's residential waste -- nearly as much as disposable diapers -- and that is creating a problem at landfill sites, The San Francisco Chronicle reported Tuesday.

If dog and cat waste don't end up inside plastic bags at a landfill, it is usually left where it falls -- to dissolve into the ground and flow, untreated, into the water table.

So San Francisco is experimenting by collecting dog droppings at one of the city's dog parks. The feces will then be placed into a methane digester that uses bacteria to create methane. The methane, once collected, can be piped into stoves, heaters or any equipment that can be powered by natural gas.

But until the technology is developed, the most ecologically friendly way to dispose of your pet's excrement is to flush it down the toilet, allowing it to be treated in a sewage system.

Copyright 2006 by United Press International