Differential Pressure

In reverse osmosis (RO) systems, the differential pressure is the pressure lost due to friction as water passes through the system. To determine the differential pressure, take a reading before the pressure vessels and after the pressure vessels of each stage, and this will inform you how much pressure was lost across that stage.

A very high concentrate flow rate will result in a high differential pressure due to the high friction. From a fouling perspective, scale, suspended solids, and biological growth build up in the feed channels and interfere with flow, thereby increasing friction and resulting in pressure losses.