"Providing Innovative Water and Wastewater Solutions"

Project Status: Start Up Diagnostics Completed 2006

U.S. Water Services Corporation (USWSC) was retained after the St. Lucie West 4.0 MGD Reverse Osmosis Water Treatment System went into operation, due to start-up and operating problems which was impacting water quality stability. The project costs for construction were substantial and shortly after going on-line the District began taking exceedences for lead in the drinking water. The problem of lead exceedences in the water supply was highly publicized in local newspapers and became a significant regulatory and community issue. The facility utilizes (3) deep wells as a raw water source. USWSC staff mobilized the necessary personnel resources with the required technical and operational experience to both diagnose and correct the operational problems. Although there was numerous technical and design issues with the facility, the primary cause of lead being dissolved into the water supply was due to improper stabilization and buffering of the finished water. RO permeate is extremely aggressive and will attack metal piping in the distribution and private plumbing systems. Often finished water pH was near 10 S.U. while corrosion persisted. It was determined that the Calcite Reactors designed to add alkalinity and hardness back into the permeate were not working properly. USWSC provided an on-site, hands-on process evaluation of the calcite media to determine solubility and a design-build solution to correct the malfunctioning units. Additionally, USWSC provided an overall RO system evaluation, operator training, revised O+M manuals, revised SCADA controls, design/build of a polyphosphate feed system and performed various repairs and redesigns to the system hydraulics. We are proud to say that the system is now performing well. USWSC continues to work for the District providing consultation support and technical resources to the ongoing utility operations as needed.