Beginning a Complete Renewal of San José-Santa Clara Regional Wastewater Facility’s Biosolids Processing Facilities

Many wastewater treatment plants face the task of rehabilitating aging digestion infrastructure while also planning for new challenges – whether for Class A digestion, changes in biosolids disposition pathways, advancing resource recovery, or improving operability and maintainability. However, very few wastewater treatment plants deal with all of these challenges at once. This is the reality that the City of San José-Santa Clara Regional Wastewater Facility (Facility) is facing as it transitions from its existing process to an entirely new biosolids treatment strategy.This paper details the decision drivers in the Biosolids Transition Study and the scope of the Digester and Thickener Facilities Upgrade Project, which, in addition to temperature-phased anaerobic digestion (TPAD), is implementing co-thickening, sludge screening, upgraded digester feed/transfer/withdrawal systems, and a new gas management system. Innovative, but proven, processes were combined to deliver a complete renewal of San José-Santa Clara’s biosolids processing facilities. Whereas many facilities are using patented or proprietary biosolids equipment and processes, San José-Santa Clara is an example of an “open source” solution to high-solids, high-performance, Class A biosolids management.