RO Systems can be simple and complex and used in various applications. For this blog we are going to just be focusing on RO Systems for water treatment applications. We get quite a few questions when it comes to Reverse Osmosis Equipment. But some of the most common questions we receive are:
- What Testing Should We Be Doing On Our RO System?
- What Pressures Should My RO Be Running At?
- What Are My Flow Rates?
- What Do We Need To Do & When Do We Need To Do It?
All RO Systems will require maintenance at some point from pre-filter changes, to membrane cleanings and much more. Every water source is different and because of this the required maintenance schedule will differ from location to location. Even how the system is designed can change how and when maintenance is performed. It can even change how often you clean your RO Membranes including what chemistry you use. In order to begin to lay out a plan it first starts with monitoring your system and that starts with a Reverse Osmosis Daily Log. This daily log should be filled out daily to help you trend the performance of the RO System. By trending this data you can begin to see trends that can begin laying out your maintenance routine.
In the example below we look at Pre Filter Pressure Inlet & Post Filter Pressure.
|Day 1||Day 2||Day 3||Day 4||Day 5|
|Pre Filter PSI||40||40||40||40||40|
|Post Filter PSI||40||34||30||25||40|
By recording the pre filter inlet pressure and post pressure we are able to identify how often we need to change the Pre Filter. As seen in this example we change the Pre filter on Day 4 which had a 15 pound differential pressure. After changing the filter we went back to 0 psi differential pressure. If we continue to trend it we may find that every 4 days we need to change the pre filter. This can then be logged as a maintenance item and now you can pre plan for your time and products to be on hand. If you have to change 1 filter every 4 days you can calculate out how many you may need for the year to keep stock.
The other items that you may be logging on the RO Log Sheet can help with other items such as RO membrane cleanings or RO membrane replacement.
Many of the major membrane manufacturers agree on the following statements:
- Reverse Osmosis membranes should be cleaned when normalized flow decreases by 10% from the initial acceptance test conditions
- Reverse Osmosis membranes should be cleaned when the overall pressure drop increases by 15% over the initial acceptance test conditions.
These two simple, explicit statements often go ignored, despite the fact that it has been demonstrated that the optimum cleaning response is achieved when these guidelines are followed. It can be difficult to recover performance if the system operates in a fouled condition for an extended period of time. Operating in a fouled condition could also cause irreversible damage to the Reverse Osmosis Membrane, which would require costly membrane replacements.
Logging this data and setting up your maintenance plan can help keep your reverse osmosis system in good operating condition. Below is a link to down load a Free RO Daily Log Sheet.