Montevina Water Treatment Plant Improvements Project – Los Gatos, CA

Challenge

SJWC’s existing 40-year old, 30 mgd Montevina WTP, who’s direct source water comes from various intakes located in the Santa Cruz Mountains south of San Jose. Providing drinking water to over a million customers throughout the area, the plant uses a mono media direct filtration process to treat the source water. During winter storm events when abundant water is available, the existing plant cannot reliably treat the high turbidity within the source water to meet current State and Federal standards for surface water filtration. In addition, the existing plant lacked tools to manage disinfection byproducts, ultimately making compliance with the Stage 2 Disinfectants/Disinfection Byproducts regulation more challenging. Other water treatment plant processes and support facilities have also reached their useful life and are in need of retirement and replacement.

Approach

SJWC used a two-step procurement (progressive design-build) process to select the design-builder for the project. The initial RFQ was followed by an RFP to three short-listed teams; with HDR selected after the proposal review and interview process.

The plants $50 million improvements include a flash mix and flocculation process followed by settling basins and a membrane filtration system. Improved solids handling facilities including clarifier thickeners and screw presses for managing residuals will be constructed. These plant improvements will allow SJWC to treat water with raw water turbidity levels as high as 100 to 500 NTU during and following storm events.

Results

Montevina WTP plant improvements will allow the SJWC to continue to deliver high quality drinking water to its customers, increase the reliability of plant facilities, and reduce SJWC’s need for more expensive imported water from other water utilities.