The alkalinity of the water ...

The alkalinity of the water according to the literature is due to hydroxides, carbonates and bicarbonates (calcium, magnesium, sulfate, phosphates, etc.). What is probably co-occurring is the precipitation of the calcium, magnesium and sulfate carbonate present in the lake water, favored by the water temperature. It is important to conduct a water analysis of the lake, to have a better diagnosis of the water. The treatment of chlorination with calcium hypochlorite also favors this precipitation (fouling in the pipeline), which can cause the pipe to rupture and cause an accident.
 The alkalinity is mainly due to the presence of bicarbonates, carbonates and hydroxides. The most common compounds are as follows:
- calcium or magnesium hydroxides;
- calcium or magnesium carbonates;
- bicarbonates of calcium or magnesium;
- bicarbonates of sodium or potassium.
Even waters with a pH of less than 7.0 (5.5 for example), can, and in general, have alkalinity, as it usually contains bicarbonates.
Depending on the pH of the water, the following compounds can be found:
- pH values ​​above 9,4: hydroxides and carbonates (caustic alkalinity);
PH values ​​between 8.3 and 9.4: carbonates and bicarbonates;
- pH values ​​between 4.4 and 8.3: only bicarbonates.

Treatment processes - Suggestion:
Ionic process of zeolites:

Zeolites are complex silicates of sodium and aluminum, which has the property of changing the sodium of its composition by other ions, such as those of calcium and magnesium, retaining these elements that cause the hardness. They are, therefore, ion exchangers.

A softening facility of this type comprises zeolite beds, similar to the quick filters, through which the hard water to be treated passes.

In summary, the reduction of hardness by the zeolites consists of exchanging the calcium and magnesium ions, responsible for the hardness of a water, by sodium ions supplied by the exchangers. After the zeolites have yielded all their sodium ions to the water, the process must be reversed by subjecting the bed of exchangers to contact with a concentrated solution of common salt for regeneration.

In contact with the brine, the zeolites make a new ionic exchange, retaining the sodium again and releasing the calcium and magnesium ions in the washing water, which is discarded.

Process with Ion Exchange Resin:

The reduction of the hardness is effected through the passage of water through a bed of cationic resin, in a process of slowing down and / or demineralization.
As this process is described in another technical document (slowdown), it will not be detailed here.