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PARAMETERS OF CHARACTERIZATION OF THE WATER
There is an amount of parameters in the water that take part not only in the quality of the same one but in the maintenance of the installation:
PH
pH is related to the proton concentration in the water. pH is defined like:
The water (H 2 O) is dissociated in protons (H + ) and ions hydroxyl ( OH - ). The product of the concentration of these species is related by a constant of balance Kw:
In a neutral situation the concentration of H + will be just as the OH - concentration reason why we will be able to express the previous equation of the following form:
If we multiply by - 1 to each side of the equation and we take logarithms we will have:
And by the definition of pH we will have in conditions of neutrality pH=7. In the same way when the water is totally dissociated in protons, pH will have an equal maximum value to 14 and will be 0 when it is totally dissociated in OH - .
The water with pH smaller of 7 it is said to be an acid water and it is said to be basic if it has pH greater than 7.
Hardness
The hardness represents a measurement of the amount of alkaline metals in the water, mainly Calcium (Ca) and Magnesium (Mg) which are originated for the dissolution of rocks and minerals. Hardness will higher when more elevated is the acidity of the water. It is a measurement, therefore, of the state of mineralization of the water.
Usually it is expressed like mg/l of CaCO3 or French degrees; it is considered that 10 mg/l is just as a French degree.
Based on this state of mineralization, we can distinguish different types of water:
Alkalinity
The alkalinity of the water is the sum of the concentrations of ions carbonate (CO 3 2- ), bicarbonate (HCO 3 - ) and hydroxides ( OH - ) (these last are despicable front to the rest).
These species produce in the water an effect plug since they absorb protons maintaining ph in a very stable value.
