The Twin Oaks Valley Water Treatment Plant (TOVWTP), located in northern San Diego County, is owned by the San Diego County Water Authority (SDCWA) and operated and maintained by Jacobs under a 15-year contract with SDCWA whose term began in 2008 with plant start-up. TOVWTP, with a rated capacity of 100 million gallons per day (mgd), comprises the following process elements: • Fine (500-um) screening (pressurized strainers) • Submerged Zeeweed 1000® ultrafiltration (SMF) • Ozonation (with option for advanced oxidation using hydrogen peroxide) • Biologically active carbon contactors (BACC) • Chloramination The plant treats State Project Water, Colorado River Water, or a blend of the two, depending on the supply schedule established by the Metropolitan Water District of Southern California (MWD), the wholesaler of water to the SDCWA. As designed, the plant is a zero liquid discharge facility, with ~99% of the raw water processed to drinking water with centrifuged solids trucked off to a regional landfill. Fine screening removes particulate matter than can damage the UF hollow fibers. SMF provides turbidity and pathogen removal (protozoa and viruses). Ozone is used for pathogen inactivation and removal of taste and odor compounds. BACC provides for further taste and odor reduction, as well as removal of ozonation by-products and selected synthetic organic compounds. Following chloramination of the BACC effluent, finished water is stored in two 7.5-mgal onsite reservoirs prior to gravity flow through the Treated Water Flow Control Facility to SDCWA’s Pipeline 4. The SMF includes backwash and chemical cleaning systems for flux (permeability) maintenance and recovery. All residuals generated from the strainers, SMF (backwash water, neutralized maintenance and recovery clean solutions (MCs and RCs) and BACC (backwash water) systems are treated by a residuals treatment system. These waste streams represent ~7% of the raw water, flow proportioned as shown in Table 1. The residuals system includes (two each) equalization basins, high-rate plate settlers (preceded by in-line coagulation/flocculation), gravity thickeners and centrifuges. All residual streams (including centrate) are discharged to, and blended in, the equalization basins.
This presentation is available to AMTA Members only.
Speaker
- James Lozier
Company
- Jacobs
Event
- AMTA/AWWA Membrane Technology Conference, Las Vegas
Session
- AMTA/AWWA Membrane Technology Conference
Date
- 02/22/22
Media
Keywords
- ZLD, flux permeability maintenance, backwash
Reference
- 9715-DP2777