BART excavation discharge headed to Cupid RowBy Alice Barnes
The Regional Water Quality Control Board has granted Tutor-Saliba/Slattery, JV, permission to discharge substantially more treated groundwater collected from the BART excavation in this community.
According to City Officials the new permit (NPDES) allows the BART contractor to upgrade its existing treatment system and to discharge up to 500,000 gpd (gallons per day) into a storm drain that runs to the Cupid Row Drainage Channel, instead of using the City's sanitary sewer.
The former groundwater/dewatering treatment system was permitted to discharge to the SSF/SB Wastewater Treatment plant up to 100,000 gpd until that limit expired on October 15, 2000. The estimated daily average flow during the wet season is 250,000 gpd.
Capacity has been increased since large filtering tanks have been installed at the end of First Avenue adjacent to the National Guard Armory.
According to Scott T. Munns, P.E., San Bruno Public Works Director, the new system will eliminate the small but additional burden on the City's sewer collection system posed by the treated groundwater. The modification to the discharge method is being done with the City's concurrence.
Although T-S/S is permitted to discharge this quantity, it is not known if it will be reaching anywhere near that amount. The estimate for water reuse on the project is 25,000 gpd, although once the rains come there should be little need for water on the project.
The former water treatment system (identified by large Denbeste blue trailers) could not discharge to the SSF/SB wastewater treatment plant during storm events. The dewatering operations are estimated to last until the spring of 2002.
The "gunk" from the treatment system will be disposed following state regulations. Water entering the treatment plant is fairly free from solids since the water comes out of dewatering wells; therefore there is no expectation of having to haul the gunk away on a regular basis.
The water will be discharge through a 4" contained PVC line trench to the storm drain located on First Avenue, south of the treatment system.
Copyright ©2001 San Bruno B.A.R.T.. Published 10/17/2001.