ELECTRODIALYSIS-

Electrodialysis (ED) is a process which uses ion exchange resin in sheet form assembled into a stack of components. ED is widely used for total dissolved solids (TDS) removal in a number of different types of plants and applications, including many public and municipal drinking water supplies

Principle:Most dissolved salts are positively and negatively charged and they will migrate to an electrode with an opposite charge.

Thus ED uses selective membranes which are able to allow the passage to either anion or cations in an alternating fashion to create concentrate and product streams.

. The anions are able to pass through the anion selective membrane, but are not able to pass by the cation selective membrane, which block their path and traps anion in brine stream.

. Similarly cations move in opposite direction through cation selective membrane under negative charge and are trapped by the anion selective membrane.

. Compartments for the electrode are at the opposite ends of the stack. The electrodes are continuously flushed to reduce scaling.

Advantages of ED:

. Low pressure requirement

. Long membrane life expectancy

. Minimal scaling and minimum chemical addition

. ED is facilities are quieter