Correction of aggressivity
Preliminary remark.
The study of physico-chemical characteristics of water and their effect on the surrounding environment, are often treated as a special case because the complexity of relations between ions.
These equilibria are unstable due to changes of temperature and concentrations of dissolved gases (escape or dissolution), which brings new reactions and consequences on the environment in contact with water.
In particular, problems of treatment of aggressivity (water), of inlay or corrosion, are generated by changes in physico-chemical equilibria and bring technical problems for the collection, conveyance and distribution of water.
Note: the study of these problems almost always leads us to what we can call the "calcocarbonic equilibrium."

Fixed aggressiveness to equilibrium.
The target is to remove carbon dioxide (CO2) from aggressive water, and if necessary increase the alkalinity (TAC) and / or Hardness (TH) of these so-called "aggressive" water.
For protection of piping distribution network, we seek to meet following quality objectives:

In general, treatment should promote a neighbor TH /TAC, and an index Larson less than 1 to limit corrosion of pipes.

Three types of treatment are possible:

* Reminder: aggressive CO2 (with respect to carbonates) is the fraction of dissolved free CO2 in excess of carbonate ion / bicarbonate [CO3] / [HCO3] and CO2 which is in association with balance of these ions.

Possibly >> see> this page (pdf file) to the balance.


Aeration treatment (removal of carbon dioxide, CO2).
Physical method, used only if CO 2 is high and for which amounts of neutralizing reagents are prohibitive.

Possible practices.
Simple ventilation:

Forced ventilation:

• runoff or spray on materials in contact tower.

Reminder: only carbon dioxide decreases, this operation leaves TAC (Alkalinity) and TH unchanged.
( link to the Hydro-Land website )

Treatment by neutralization.
A chemical process, which allows the CO2 removal per neutralization with a basic reagent ( x-OH-).
Main simplified reaction: CO2 + x-OH- >>> x (HCO3-)

Possible main practices:

Reagents which act only on the Hardness (not CO2 neutralization)

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