City of Tustin PFAS Treatment System and Influent Conveyance

Butier Engineering, Inc., in collaboration with Orange County Water District (OCWD) and the City of Tustin, provided construction management, field QA/QC, and geotechnical and materials testing services (Ninyo & Moore) for this critical water treatment project. Portions of Tustin’s groundwater supply have been contaminated by per- and polyfluoroalkyl substances (PFAS), which are prevalent in the environment and commonly used in various consumer, commercial, and industrial products. OCWD and the City of Tustin worked together to implement a new treatment system at the existing Main Street Water Treatment Plant to eliminate these compounds and continue to provide safe and reliable drinking water supplies to the Tustin customers.

Scope of Work

• Demolishing the existing reverse osmosis and ion exchange (IX) treatment system
• Installing eight (8) new IX vessels and a new sodium hypochlorite storage and disinfection system to treat the water from the extraction wells
• Replacing the existing nitrate treatment system
• Constructing a new section of distribution piping from the existing treatment plant
• Upgrading the booster pumps to accommodate increased flows
• Sewer and storm drain improvements
• Installing new electrical service, motor control centers, variable frequency drives, automatic transfer switch, and instrumentation and controls
• Upgrading the City's existing SCADA system
• Installing nearly 3 miles of conveyance pipeline to transport water from four offsite wells to the new water treatment system
• Pipeline construction involved asphalt removal and replacement, striping, and traffic control

Project Challenges/Solutions

• Night Work: Jack and bore operations were implemented under culverts, and a significant amount of work was done at night to accommodate residents and businesses.
• Traffic Coordination: The worksite was in Old Town Tustin, a heavily traveled live/work area that needed to remain open to public access. This required extensive coordination to ensure construction was performed safely and efficiently without causing disruptions.

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