"It's a tradition for many people to grab a newspaper, their dog's leash and a plastic bag before going on a walk," Reed told Animal Planet News. "They use the plastic bag to pick up his little gift."
In the future, the plastic bags likely will be made out of biodegradable materials so they won't gum up the process or have to be separated from their pungent contents. If the test phase moves forward, Norcal hopes to put a collection bin in Duboce Park, a popular San Francisco park for dog walkers. Once collected, the poo would be placed into a methane digester, which is sort of like a compost bin for dung.
Similar to plant composting, methane digesting allows bacteria to break down the initial raw product. Animal feces naturally contain microbes called methanogens, which live off hydrogen and carbon dioxide that are produced by other microbes. In addition to being in animal waste, methanogens are in many other environments without free sources of oxygen, such as mucky swamps and marshes, sewage sludge and the guts of termites.
The methanogens use hydrogen as a source of electrons for breaking down carbon dioxide into microbial food. Methane gas is a byproduct of the process. The resulting biogas is energy gold. It can be piped to stoves, turbines, heaters, and other equipment that may run on natural gas.
