The present international and European Union guidelines on water consumption provide for drastic reductions in the water resources for agricultural, civil and industrial uses, imposing the partial or total recycling of the wastewaters resulting from the primary working cycles in which the water is used.

Liquid colloidal dispersions are characterized by dispersions of solids, liquids or gases into a homogeneous liquid. Two stability factors enable the particles of the different substances to remain in suspension and separate so as to form a liquid colloidal dispersion: electric charge or solvation.

Electric charge causes the repulsion of the particles and is determined by the absorption of ions onto their surface.

Solvation is determined by the tendency of many substances to cause the molecules of the polar liquid in which they are suspended to strongly adhere thereon, forming a coating which prevents them from joining and thickening.

The treatment of liquid colloidal dispersions characterized by electrically charged particles involves no particular difficulties, in that the addition of electrolytes reduces the dispersion, causing the flocculation of the dispersed impurities.

The problem created by solvated particles is instead more difficult to solve, since solvation confers to the colloids a far higher stability than electric charge. Solvated particles are practically insensitive to the action of electrolytes and furthermore, polar liquids allow stable suspensions to be formed also with relatively large particles (emulsions and/or suspensions of bentonites, clays, kaolin and the like).

Hence there is an unsatisfied demand for a simple and economic process, apt to efficiently separate solvated impurities from polar liquid wastes containing colloidal dispersions thereof, so as to allow the resulting clear liquid to be recycled or discharged into its natural environment with no pollution problems. Since many primary working processes make use of large quantities of fresh water, a process of this type would provide the considerable advantage of drastically reducing fresh water consumption; in fact, once the dispersed impurities have been removed, it would often be possible to recycle the water initially used in the primary process.

Such a process will obviously be the more advantageous, the higher the possibilities of its universal use, independently from the nature of the solvated impurities.