APP 1.8

Measure SDI before RO membrane inlet every 4 weeks using standard SDI test kit (0.45 µm filter, 15 minutes). SDI must remain below 3.0. If exceeding 3.0, pretreatment (multimedia filter, carbon filter, cartridge filter) requires backwashing and cartridge replacement

Monthly baseline pressure differential monitoring across membrane stages. A sudden spike in differential pressure (> 10% increase from baseline) indicates fouling. Visual inspection for yellow slime (biofouling) or white crystals (scaling). Inspect feed spacer geometry and membrane autopsy if fouling suspected

Verify APP/PAH pump discharge pressure at standard flow rates weekly. Compare with baseline. Monitor power consumption (kW input). Check for cavitation noise or abnormal vibration. Verify pump inlet pressure 0.5-5 bar (7-72 psi). Inspect for seal leaks and corrosion on stainless steel surfaces

Monitor ERD inlet/outlet pressures and flows monthly. Compare energy recovery efficiency to baseline (typically 92%). Inspect for scaling/fouling by measuring pressure drop across ERD. Visual inspection of high-pressure spacer for biofilm buildup. For MPE 70, verify motor rotation speed (650-875 rpm) and electrical current

Monitor prefilter differential pressure weekly (must stay below 1.5 bar; replace when reaching limit). Inspect cartridge visual condition (melt blown polypropylene for 3 µm stage, 10 µ absolute for main stage). Replace cartridges immediately if pressure differential exceeds maximum or after 12 months operation. Verify Beta 5000 rating for main filters (10 µ absolute minimum)