Dan Duffield of the Richmond Municipal Sewer District, CWEA member and Environmental Compliance Inspector Grade 4 is quoted in a recent story in the Municipal Sewer and Water magazine about how the District is keeping infiltration and inflow (I&I) at bay.
Richmond Municipal Sewer District sets an example with its work to reduce SSOs and protect San Francisco Bay.
Richmond, California, enjoys 32 miles of coastline, the most of any city in the San Francisco Bay Area, but this geography has its downside.
“During heavy or prolonged rain events, our treatment plant flow can increase from 5 mgd to 40 mgd,” says Dan Duffield, source control inspector for the Richmond Municipal Sewer District.
The I&I comes from direct tidal inflow in the southern basin near the Bay, groundwater infiltration from tidal saturation, storm runoff inflow from connections between stormwater sources (downspouts and sumps) and the sewer system, and rainfall-dependent infiltration. Many Bay Area communities experience similar issues.
“The goal of our sewer collections system master plan is to eliminate SSOs during conditions up to a 10-year 24-hour storm event,” Duffield adds. “That equates to 4.2 inches of rain in 24 hours, and could send 70 mgd to the plant. As our collections system is repaired and I&I is reduced, that reduction will be the measure of our success.”
In 2002, the district contracted with Veolia North America (formerly U.S. Filter), a provider of environmental services in cleaning, energy, waste and water. Beginning in September 2014, Veolia now runs the treatment plant and collections system. It was an auspicious start to I&I management, but more was soon to be needed.
The original master plan was conceived in 2006, when RMSD entered into an agreement with San Francisco Baykeeper, an NGO founded in 1989 to protect water quality in the Bay Area. Baykeeper wields considerable power with extensive grass-roots support — and it was threatening a lawsuit.
“That was a controversial time,” recalls Richmond Mayor Tom Butt. “I’ve always supported the Clean Water Act, knew we had some problems, and wanted to do what was right for the Bay. And the law was on Baykeeper’s side. The EPA counts on local organizations to do their enforcement, so that’s where Baykeeper came in.”
As a result of this agreement, RMSD was required to reduce SSOs by 90 percent by 2016, and to eliminate overflows into the Bay from their two engineered overflow weirs. The 5-million-gallon wet weather storage facility was also a result of this agreement.
See the full story here: California Utility Keeping I&I at Bay