Potabilization and Filtration Systems
Potabilisation plants
The solutions the company can adopt depend on the characteristics of the water and the water treatment technology used. The basis for achieving a proper solution to the water-related business problem is an appropriate analysis of the incoming or feed water and then to a commensurate design that leads to the definition of the most suitable treatment and proper sizing.
Depending on the source of supply, the water is more or less close to the characteristics of potability, hygiene, quality. The function of the drinking water plant is to remove natural or man-made elements that have contaminated the water or are present in excess: pollutants, minerals, bacteria, and viruses.
In addition, depending on the available space, it is also possible to size and design the external skid according to the requirements.
Depending on the degree of contamination, pollution, alteration of values, water needs different treatments. A drinking water plant is more or less articulated and may consist of different stages.
- Physical Treatments
- Chemical treatments
- Refinement
- Disinfection
Legislative Decree 152/2006 distinguishes water into 3 categories that require different treatments :
- Waters requiring physical treatment and disinfection
- Waters requiring physical, chemical and disinfection treatments
- Waters that require more intensive treatment, including refining
Example of a Potabilization Plant
To the water treatment plant comes the feed water, untreated.
The first stage involves the introduction of substances capable of “intercepting” non-settling solids, which then aggregate into flocs through the flocculation process. At this stage aggregating substances, precisely flocculating agents ( aluminum sulfate or ferric chloride) are fed into the treatment, aggregation of particles is achieved, which are later separated from the water by filtration. The neutralization of surface charges facilitates the formation of the first small solid aggregates, which subsequently tend to enlarge by adsorption of particles until the formation of the first flakes in suspension.
To improve the process, powerful agitators are used; in flocculation, agitation is not convenient because it tends to break up the formed flakes. Flocculating agents, which can be anionic or cationic, depending on the charge of the surface particles to be destabilized generally provide for their use in a specific pH range. One application that takes advantage of the flocculation phenomenon is clariflocculation plants used for water treatment. In this process, the suspended particles in solution form larger aggregates of sufficient weight to precipitate and then be separated from the wastewater as sediment. In the first stage, the equipment used for coagulation must perform rapid and vigorous agitation for dissolution and dispersion of the coagulant. For the second flocculation step, moderate and slow agitation is required so that the destabilized colloidal particles form flocs of sufficient size to settle. This operation is conducted either in a tank equipped with agitation, or within successive settling units, using sludge recirculation. This type of plant, which requires low quantities of water and relatively low costs, is used for preliminary treatments to make potable water such that it can be chlorinated, stored and sent to the distribution system through a pressurization unit.
