The City is poised to approve a $14 million, three-year contract to buy 27 million pounds of bleach, a good portion of which will be poured into The City’s sewer systems to prevent San Francisco from smelling during the summer — or at least prevent it from smelling worse.
The bleach is injected at three major points in The City, primarily during warmer months, to help control sewer odor: around Bay Street and Embarcadero, in the Mission Creek area and in the Richmond district, officials said. Bleach, or sodium hypochlorite, acts as a binding agent to hydrogen sulfide, the chemical compound that is code for the infamous "rotten egg" smell, according to San Francisco Public Utilities Commission spokesman Tyrone Jue.
Increasing the smelly threat is The City’s water conservation effort. "The consumption of water has decreased significantly. We are having a difficult time having enough water to convey the material to the treatment plants," said Tommy Moala, assistant general manager for the SFPUC.
San Francisco’s sewer system transports both sewage and storm water using the same pipelines. The farther the trip and the longer the waste remains in the pipelines, the smellier it could become.
"During the rainy season, our combined sewers allow rainwater to act as a natural flushing agent to clean out the sewers and reduce odors," Jue said. "This is why we usually don’t need to add any chemicals during the winter season."
Jue said the bleach is neutralized before it enters the Bay, thus mitigating any environmental impacts.
The Board of Supervisors Budget and Finance Committee approved the contract Wednesday. The full board is expected to vote on the agreement on March 1.