An important part of operating membrane systems is accurate data collection on a daily basis. The data will help predict normal maintenance schedules and will help determine the cause of any system upsets. Comprehensive data is very useful in determining when the membranes need to be chemically cleaned, or eventually replaced. It also alerts the operator to changes taking place such as fouling, leaking “O” rings etc.
It is important to check on the level of semi-colloidal suspended solids in the feedwater to RO systems. The level can be estimated (not measured absolutely) by the Silt Density Index or SDI test which measures the blocking rate of a 0.45 micron filter pad under controlled pressure conditions.