Desalination is the production of freshwater from saline water, either from the sea or from groundwater. There are a couple of drivers for this process; either the requirement for fresh water for drinking and industrial use or the requirement to minimise or eliminate liquid waste (zero liquid discharge or ZLD).

 

The Solution

Thermal Desalination (Multi-Effect Distillation; Flash Distillation; Vapour Compression) is based upon the evaporation and condensation of the water component, leaving the salts behind.  This requires heat to facilitate the evaporation and is most often seen where there is significant waste heat - power stations being the prime example.

 

Reverse Osmosis is a membrane based water separation system relying on pressure to overcome the natural osmotic properties of semi-permeable membranes. Forward Osmosis also uses semi-permeable membranes, but in the opposite direction, using the natural tendency of water to permeate from a weak salt solution to a concentrated one.   An artificially constructed saline draw solution forms a concentration gradient across the membrane causing the water to diffuse from the feed solution to the draw solution, which is then filtered to recover the water. Membrane Diffusion combines both membrane and thermal aspects, evaporating water through a vapour phase membrane and re-condensing it.

 

Our Capability

The most effective and economical system choice for desalination is complex and dependent upon many of the factor.  Action work closely with their clients to select the most appropriate technology, together with the required pre- and post- filter packages.A variety of contractual options are available, from straightforward sale of units through to leasing, BOO or BOOT models.