Water treatment before use - Fields and applications

The two previous reports were devoted to examining the various unit treatments relating to particulate matter. and dissolved substances . The question now is how they can be combined in more or less complex processes, the purpose of which may sometimes be limited to simple clarification and disinfection of water, while in other cases it will also be necessary to provide for refinement (elimination of micropollutants and improvement of organoleptic characteristics), reducing its hardness by decarbonation with lime or resin softening, demineralization using ion exchangers and/or membranes, to mention only the overall treatments; More specific treatments may also be required, such as the removal of certain dissolved gases (O ₂ , N ₂ , CO ₂ , H ₂ S), iron and manganese, ammonium or nitrates, etc.

This dossier therefore provides a description of the arrangement of unit processes in treatment streams and their potential applications in various industries. It is obviously not possible to cover the subject exhaustively, given its great diversity:

• water resources (including seawater and brackish water, when easily accessible and suitable for use); in some cases, industrial users may also only need to carry out additional treatment if they are connected to the drinking water network; the following mainly concerns the treatment of natural fresh water, whether surface water or groundwater; for techniques for desalinating seawater or brackish water, please refer to ; another type of resource, already discussed in the introduction to this section on "Water." , consists of recycled or reused factory effluents, which sometimes require very advanced treatment, as described in ;

• the required water qualities depending on the type of industry and water uses within the same plant (see  );

• of the range of treatments and channels available.

We will therefore have to limit ourselves to the most common cases, which may include:

• either simple rough treatment (e.g., screening, settling alone, direct filtration without reagents) for washing, transport, or cooling water;

• either clarification and/or refinement treatment to produce industrial water of a quality similar to that of drinking water (e.g., food processing, bottled water, paper mills, textile industries);

• This involves...