If a local activist gets his way, the City of San Francisco could become one of the first in the nation to pilot test a composting toilet system.

Eric Brooks, chair of the San Francisco Green Party's sustainability working group, has proposed that the city test several composting toilet models outdoors and in public buildings to determine if it is feasible to deploy the units citywide. He views a comprehensive composting toilet system as a way to address the city's aging sewers, save water, reduce the use of sterilization chemicals and potentially create hundreds of green jobs in the process.

Brooks has been advocating composting toilets to the San Francisco Public Utilities Commission for more than a year. An informational report commissioned by the agency on composting toilets was released in October, finding that while a composting toilet is more expensive that a conventional one, there may be a cost advantage in cases where significant sewer upgrades are necessary or if water and energy prices increase.

Diverting human bathroom waste toward organic composting, rather than separating the human waste from wastewater, would reduce treatment costs and free wastewater treatment plants to focus on removing chemicals and other biological input from the water system. At the same time, the potential for water savings in the city could be signifcant.

"If every toilet in the city was a composting toilet, that would save over 5 billion gallons per year because each (composting) toilet saves 6,600 gallons per person per year," said Brooks, who is also campaign coordinator at the grassroots organization Our City.

Seattle, Austin and New York are among the U.S. cities that have explored public composting toilets, but perhaps not quite at the same scale as Brooks' proposal. The local business community, he believes, would be able to save both water and money, similar to their adoption of energy efficiency technologies.

"Businesses will want to switch to something that saves them more water, just as they wanted to switch to things that saved them electricity,"

Water stress and scarcity, Brooks noted, promise to become even more acute in the coming years because of climate change.

"If we get ahead of this in time over next few decades, we will be solving a climate-induced water crisis before it happens."

Image CC licensed by Flickr user redjar.