Wastewater Reliability Evaluation and Prioritized Facilities Improvement Plan
Mt. View Sanitary District, California

West Yost recently performed a facility reliability, condition assessment, regulatory compliance evaluation, and recommendations plan for Mt. View Sanitary District’s Wastewater Treatment Plant (WWTP).The District’s WWTP consists of a full-compliment of unit processes that provide screening, clarification, biological treatment with nitrification, filtration, and UV disinfection to meet the standards for reuse in a wetlands, and ultimate disposal into San Pablo Bay. Solids handling facilities include grit separation, sludge thickening, anaerobic digestion, dewatering, and drying.

The WWTP has an excellent compliance history and has historically been able to achieve the needs for wastewater treatment and solids management. However, the District received a new permit in 2010 from the San Francisco Bay Regional Water Quality Control Board that included more stringent ammonia limitations, tighter restrictions on equipment bypasses, and lower winter-season bacteria limitations. Review of the WWTP facilities and operating data revealed a number of issues that could compromise reliability in meeting the treatment standards long-term.

The assessment included a variety of plant components with particular emphasis on evaluation of the headworks, influent pumps, clarifiers, filter feed pumps, biofilter/biotower, UV disinfection, and digesters. As a result of these efforts, West Yost provided a facility assessment and a prioritized long-term facility improvement plan for the District.

Solutions to improve the reliability include: increased hydraulic capacity and provisions for redundancy for the most critical facilities; added secondary process treatment capacity to ensure reliable compliance with more restrictive ammonia limitations; identification of cost effective, easily implemented, and regulatory compliant means for bypass during periods of necessary shut-down or failure; and other system improvements, including installation of new UV disinfection equipment and installation of a FOG receiving satiation that will provide long-term cost benefits to the District.