... → multi-media filter(sands filter) → active carbon filter → water softener(or inhibitor dosing)→PP filter→ high-pressure pump →RO system→PH adjust system →RO tank →EDI ... .2PP filterPrevent large particles, iron, dust, SS matter,impurity into RO membrane.2.3RO membraneRemves: lead, cooper, barium, chromium, mercury,sodium, cadmium ...