Factors that influence the performance of RO systems

Permeate flux and salt retention are the main parameters that determine the performance of a Reverse Osmosis system. These factors are mainly influenced by the following variables:

· Pressure
· Temperature
· Recovery
· Salt concentration of the feed water

These variables each influence the performance of the system in their own way. In the images below, you can see the effects of each of the above-mentioned parameters on the performance, when each of the other parameters are continual. In practice, performances are usually influenced by multiple parameters.

Pressure

When the effective pressure of the feed water is increased, the dissolved solids content of the permeate will decrease, while the permeate flux increases.

Performance and pressure

Temperature

When temperatures increase and other parameters are continual, the permeate flux and the salt flow will increase.

Performance and temperature

Recovery

The recovery means the relation between the permeate flow and the feed water flow. When recovery increases, the permeate flux will decrease and stagnate, when salt concentrations are of a value where osmotic pressure equals feed pressure. When recovery increases, the salt retention will decrease.

Performance and recovery

Salt concentration of the feed water

The effects of the salt concentration of the feed water on the permeate flux and salt retention are shown here.

Performance and salt retention

* Graphic images are from FILMTEC membranes

Reverse Osmosis