Distribution water - Treatment processes

Depending on the availability and quality of resources, raw water for drinking water production is drawn from groundwater or surface water (rivers, canals, natural or reservoir lakes, etc.). Although 95% of the resources used are of underground origin, they account for only 66% of the volumes tapped. Conversely, surface water represents 4.6% of total resources, but accounts for more than a third of volumes tapped (34%).

Current regulations are based on Decree no. 2003-461 of May 21, 2003 concerning certain regulatory provisions of the Public Health Code (Title II, Chapter 1 ^er ), in particular the section on "Waters intended for human consumption, excluding natural mineral waters".

In the 1960s-1970s, groundwater was simply pumped, chlorinated and distributed. All surface water treatment systems were designed according to the classic "coagulation, flocculation, decantation, deep filtration, disinfection" scheme, with almost systematic pre-chlorination, enabling the various processes to work in a chlorinated environment without any biological phenomena taking place.

The considerable development of knowledge in analytical chemistry and toxicology, the publication of new regulations and consumer demands all help to explain why these processes evolved considerably from the 1970s-1980s onwards (elimination of pre-chlorination, optimization of organic matter removal, introduction of refining treatments such as ozonation/filtration on granular activated carbon). These processes are referred to as "conventional" in this article.

Conventional treatment systems can sometimes – and will be even more so in the future – present limitations in terms of efficiency and/or reliability. Since the end of the 1980s, and much more frequently today, membranes have provided new solutions which, although not universal and widespread, undeniably make it possible to lighten the sizing and operation of the system and improve product quality. Microfiltration,...