membrane separation

Osmosis and reverse osmosis phenomena have been known for over one hundred years. However, we had to wait until the 60's and the development of synthetic membranes for these principles to become industrialised.

After the 70’s, membrane separation processes made major advances through :

• the number of membranes developed and then marketed;
• their performances and, therefore, their industrial application potential for processing water as well as other fluids.

Without wishing to appear simplistic, in this section, we will attempt to classify and describe these membranes, limiting ourselves to those membranes and processes that apply to the treatment of aqueous solutions and suspensions that may arise, based on :

• either their structure;
• or the way in which water and solutes are conveyed through these membranes;
• or by their function: desalination or clarification membrane.

Finally, this section provides a description of membrane operating methods and of the major parameters governing their performance.

It should be noted that after having become prevalent in "clean" water applications (drinking water – process water – seawater desalination), over the recent decade, they have gradually moved into the wastewater field: tertiary treatment for UWW or IWW with a view to their recycling, and BRM (biological membrane reactor).

The chapter separation by membranes examines the main options available when designing a membrane system, together with the main applications of such systems in water treatment; finally, chapters drinking water treatment, treatment and conditioning of industrial water and industrial processes and effluent treatment, provide examples illustrating how these systems have been incorporated into treatment trains for all water types.