... pressure difference over 10Psi (0.7kg/cm2) or water SDI> 5, the need for backwashing . In general, before running back wash ... .Under normal circumstances, it needs to backwash once a week.5μm security filterThe third pretreatment, filter spray for the polypropylene melt ... ≤ 0.1mg / L Salinity≤ 300ppm Iron≤ 0.1 ppm Temperature :5-35 °C Turbidity ≤ 5NTU PH 6 - 8 2. Equipment Specifications ...