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Designing pressure UF as RO pretreatment
Define a pressure ultrafiltration stage that delivers a consistent and verifiable RO feed.
HOSON WATER editorial ·
Define the RO feed at the interface
Begin with the downstream membrane requirements and a feed-water analysis that captures normal and adverse conditions. Document the target turbidity or fouling index, sampling point and testing method. UF is suited to suspended and colloidal material. Pretreatment may still need to address dissolved compounds, oxidation conditions, oil or source-specific chemistry before water reaches the RO membrane.
Protect the connection between the two stages
Record the required flow, pressure and tank capacity at the RO feed. Define whether UF backwash can interrupt the RO train and how a low buffer level changes the operating sequence. Give each train a method to isolate and test it independently. Include an off-spec diversion or interlock where the site requires it.
Trend the signals that reveal which stage changed
Keep UF filtrate quality, pressure and backwash history with the RO flow, conductivity and pressure trends. Compare operating measurements under similar feed conditions. When RO performance declines, the shared record helps determine whether a shift began in the source, the UF process or within the RO train.