TECHNOLOGY INNOVATIONS THAT PROVIDE FLEXIBILITY FOR RELIABLE BIOLOGICAL NUTRIENT REMOVAL AND PHASED SITE SPACE UTILIZATION: CHALLENGES AND SOLUTIONS

The San Mateo Wastewater Treatment Plant (WWTP) is operated by the City of San Mateo, and treats flows from the City of San Mateo as well as the surrounding communities. The design capacity of the plant is 15.7 mgd, with planning level wet weather flows varying between 72 and 98 mgd. The facility currently consists of primary clarification, aeration basins for short SRT activated sludge operation, secondary clarifiers, pressure filtration, chlorine disinfection, and dechlorination. In addition to the current NPDES permit requirements, the facility is required to provide wet weather treatment that could result in greater than 7.5 fold flow peaking over average flow conditions. Also, the facility is located in the San Francisco Bay Area that is currently being evaluated for potential impairment with pending nutrient removal requirements to be imposed on the dischargers. The City has evaluated options to optimize the existing facility using select treatment technology options to meet three increasing levels of nutrient treatment and implement wet weather treatment in parallel to the future facilities planning.