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Silt Density Index

What is SDI (Silt Density Index)?

SDI stands for Silt Density Index. A 15-minute filter test that quantifies how much suspended fine matter is in the feed. RO membranes need SDI < 5 to avoid premature fouling.

  • CIP

    An automated cleaning cycle that flushes a piping system or RO train with hot water and detergents without dismantling it. Standard practice in food, beverage, dairy and pharma to keep surfaces sanitary between batches.

  • CIP-cycle

    A single Clean-In-Place run — typically a sequence of caustic flush, acid flush, then rinse — used to remove biofilm, mineral scale and organic foulants from a system between production batches.

  • FR

    Membrane variant with a more open feed-spacer and tweaked surface chemistry to handle high-fouling streams (textile, food, ETP) before scaling forces a clean.

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