Project–At–A–Glance

WSIP Region
Peninsula

Location
Unincorporated
San Mateo County

Construction Start
April, 2011

Construction Finish
December, 2013

Current Status
Design, Environmental

Project Cost
$176M

The purpose of this project is to improve delivery reliability and provide seismic upgrades at the Harry Tracy Water Treatment Plant (HTWTP) to achieve a sustained capacity of 140 million gallons per day (mgd) for at least 60 days, and to provide 140 mgd within 24 hours following a seismic event on the San Andreas Fault. The sustainable capacity would be provided through the addition of filters, upgrades to various systems, and seismic retrofits of all critical process units. 

The HTWTP is currently a direct filtration plant; no sedimentation processes are employed upstream of the filters.  The raw water quality from the Peninsula reservoirs, while typically of very high quality, can vary significantly and may occasionally be relatively poor due to sporadic filter-clogging algae blooms and high turbidity events. Planning studies concluded that the direct filtration process can adequately treat poor raw water quality and meet all water quality requirements, however, the plant capacity may be diminished since the filters clog more rapidly.  In order to assure capacity under all raw water quality conditions, implementation of a clarification process was recommended.  During the planning process, it was decided that the frequency of poor raw water quality events was acceptable to continue employing the direct filtration process, but that new filters should be added to ensure capacity under most water quality conditions.  The project is provided in response to the Seismic Reliability and Delivery Reliability level of service goals, and also addresses maintaining regulatory compliance in the Water Quality level of service goals.

Description
The project would consist of:

• Replacement or upgrades to the six existing pumps in the Raw Water Pump Station.
• Hydraulic improvements in the various treatment units to reduce headloss and increase capacity.
• Improvements to the disinfection process by upgrading the ozone generation system and backup oxygen supply.
• Expansion of the filtration process capacity by adding five new filters.
• Improvements to the sludge handling system, including the addition of improved thickening and dewatering systems.
• Seismic upgrades to all critical process units.
• Electrical upgrades, including a new substation, switchgear, and motor control center. New emergency generators are being provided as part of the Standby Power Facilities Project.
• Miscellaneous improvements to chemical feed systems, site piping, drainage, and roads.

Note: Schedule and cost information shown may vary from the 2007 Approved WSIP Schedule and Budget. The information shown reflects the current forecast information published in the latest WSIP Quarterly Report.