Physical treatment
The physical treatment of water consists of the use of filtration techniques that involve the use of filtering media such as sand, membranes, screens or any other type of physical barrier serving as a separation element between the contaminants and the aqueous solution in question.
Knowing that physical treatments require the addition of a physically binding filtration element, among these technologies, we find all types of membrane filtration (microfiltration, ultrafiltration and nanofiltration), reverse osmosis, other types of filters (discs, sieves, self-cleaning, etc.), some media filters and sedimentation basins
Chemical treatments
Unlike physical treatments, chemical treatments do not use any barriers during treatment. On the contrary, as its name suggests, the use of chemicals is prioritized. The chemicals used will attack the contaminants present in the water in order to facilitate their separation and extraction.
Parmi les traitements chimiques les plus répandus, on peut penser à la précipitation, la neutralisation, l’adsorption, la désinfection (Chlore, ozone, ultraviolet) et l’échange ionique. Bien qu’il existe d’autres types de technologies comme les procédés d’oxydation avancés, celles citées plus haut résument bien les différents traitements chimiques existants.
Physical-chemical treatments
Physical-chemical treatments are treatments that use certain chemicals to modify the physical state of the contaminants in order to extract them in a physical way. Several types of physico-chemical treatments exist, the most widespread are coagulation, flocculation, flotation, neutralization and electroflotation.
As an example, coagulation and flocculation are generally used together since they work in much the same way. The addition of a coagulant allows the agglomeration of dissolved solids present in the water, i.e. TDS. Once they have agglomerated, they become massive enough to be considered as Total Suspended Solids (TSS). Normally, coagulation could stop here and filtration could remove the TSS. However, it is common to add flocculant afterwards to agglomerate the TSS. The clusters of particles become too massive to float and will end up at the bottom of the water where a drain can extract them.
This example was used to highlight the functioning of physical-chemical treatments.