Reverse Osmosis / Desalination

Reverse Osmosis membranes are available from a range of manufacturers in Tubular, Hollow Fibre and Spiral Wound configurations. Hollow Fibre membranes have only a very limited number of applications and tubular membranes are used only in wastewater and specialised industrial applications. The vast majority of RO membrane applications are now for the Spiral Wound configuration due to the fact that a large surface area is packed into a small volume, whilst retaining low fouling characteristics.

Spiral wound RO membranes are often subdivided into the sub-categories below and each manufacturer offers membranes to cover this range. These membranes are generally limited to an operating temperature of 45 degrees C.

  • Low-pressure membranes - These have a limited operating pressure of around 20 bar and are often used for removal of nitrates from drinking water, but also to remove TDS / Conductivity from municipal water supplies for industrial applications such as boiler feed.
  • Medium pressure membranes - These are rated for operating pressure of up to 40 bar and are widely used for TDS / Conductivity reduction for drinking water applications around the world and also for a range of industrial applications.
  • High pressure membranes - These are rated for operating pressure of up to 80 bar and are used for seawater desalination world as well as for a range of industrial applications.

There are a smaller number of membrane manufactures offering specialist membranes for high value applications. These include.

  • High temperature applications (up to 80 degrees in some cases).
  • Specialist materials - PTFE, PVDF etc to cope with aggressive or highly fouling solutions.
  • Sanitary grade materials for food production.
  • etc