Santa Monica Sustainable Water Infrastructure Project

Santa Monica, CA


PACE was responsible for the design of the Advanced Water Treatment Facility (AWTF), a key component of the City of Santa Monica’s Sustainable Water Infrastructure Project (SWIP). The AWTF treats a combination of raw wastewater and harvested stormwater and produces 1.0 million gallons per day (MGD) of purified water for groundwater augmentation. This facility is one of the first to take in raw wastewater and stormwater, fully oxidize the stream via biological treatment, and provide pathogen reduction to meet California Title 22 regulations for Indirect Potable Reuse (IPR) of 12-log virus, 10-log cryptosporidium, and 10-log giardia, all within one facility.


The treatment process consists of a five-barrier stream: membrane bioreactor (MBR), cartridge filtration, reverse osmosis (RO), ultraviolet advanced oxidation process (UVAOP), and chlorine disinfection. The facility is the first to receive pathogen credits through the MBR and cartridge filtration processes by being deliberate in the selection of the equipment and design of the systems to remain within certain operating envelopes. The RO uses total organic carbon (TOC) as a surrogate parameter to measure pathogen reduction, which allows a higher pathogen reduction value to be claimed than typical conductivity. UVAOP uses free chlorine as the oxidant to reduce the number of chemicals required on-site. Residual chlorine provides downstream process benefits for chlorine disinfection.


The AWTF is a completely subterranean facility in an urbanized area, located underneath the Civic Center parking lot. The first level belowground serves as the mechanical treatment area and houses the process equipment. The second level belowground contains process tanks, including MBR tanks, filtrate storage, chlorine contact tank, and purified water clearwell.


The SWIP protects Santa Monica beaches by preventing discharge of polluted stormwater from the Pico-Kenter Outfall to the Santa Monica Bay. The SWIP will significantly improve beach water quality, resulting in cleaner and healthier beaches, an enhanced visitor experience, and closer compliance with the National Pollutant Discharge Elimination System (NPDES) permit.


Key Features:

  • Sustainable production of 1,680 acre-feet per year through IPR
  • 50% reduction of the City’s dependence on imported water
  • Improved beach water quality by storing and treating first-flush stormwater for reuse
  • Automated MBR features with combined screened primary and return activated sludge (RAS), foam control, flux management, and real-time water quality monitoring
  • Minimal space and visual impact through underground installation, ideal for an urban location

PERC Water, as a sub to Kiewit for the City of Santa Monica

Published Articles

Wastewater Treatment / Recycled Water