Finer filtration

recently won the annual Engineering Achievement Award from the

(CWEA), Santa Clara Valley Section, for a new filtration approach that could significantly improve filtration performance in wastewater treatment, thereby reducing operations and maintenance costs.

The new filtration approach involves the use of a relatively large-diameter filter medium in conjunction with air-enhanced backwash procedures. According to the firm, the method has performed beyond expectations in an ongoing plant-scale study at the South Bayside System Authority (SBSA) wastewater treatment plant. The SBSA processes approximately 20 million gallons of wastewater per day and serves the cities of Menlo Park, Redwood City, Atherton, Portola Valley, Woodside, San Carlos, and Belmont.

Typically, solids are removed from wastewater using granular filters in a dual medium configuration of anthracite (coal) and sand. The configuration for this project uses a monobed (single-layer) anthracite that is approximately 2.5 times larger in diameter than SBSA’s existing media.