Membrane technologies
Membrane technologies are processes which allow the separation of the different components of a fluid based on their size. The right choice of membrane cut-off can for example enable a clarification (separation of suspended solids) which can be achieved with a microfiltration, or it can allow the extraction of pesticides by means of nanofiltration.
Depending upon their pore size and upon the hydraulic pressure required for the separation, the four membrane systems commonly in use for the treatment of drinking water are detailed in the following table:
| Pore size | Pressure (bar) | |
|---|---|---|
| Microfiltration | 0.1 - 1 μm | 0.1 - 2 |
| Ultrafiltration | 5 nm - 0.1 μm | 0.1 - 5 |
| Nanofiltration | 1 - 5 nm | 5 - 15 |
| Reverse osmosis | < 1 nm | 8 - 50 |
