When Should RO Membranes Be Cleaned?
July 31, 2020 - Nathan Olszak
When Should RO Membranes Be Cleaned?
What To Look For
Membranes need to be cleaned when either…
- differential pressure increases by 50%
- normalized flow drops by 10-15%
- salt rejection decreases at least 2%
The key to knowing when membranes need to be cleaned is to consistently collect data with the start-up of your RO system and ongoing. It is much easier to evaluate your system’s performance if you track the trends in data.
How To Clean Your RO Membranes
With this continuously obtained and calculated data, it is much easier to determine when your RO membranes is in need of a cleaning. You can learn more about how to clean these RO membranes by reading our article about how to do this step-by-step.
Data to Collect & Monitor
To have all the data needed to evaluate your RO System, the following categories should be monitored…
- Feed Pressure
- Feed TDS
- Permeate TDS
- Reject TDS
- Reject Pressure
- Permeate Pressure
- Feed Water Temperature
- Reject Flow
- Permeate Flow
What This Data Can Determine
From the above data, the following can be determined and tracked to ensure that RO membranes are cleaned when it is necessary:
- Normalized Permeate Flow Rate
- Normalized Delta Pressure
- System Percentage Salt Rejection
- System Percentage Recovery
- Net Driving Pressure
