The use of oxygen as oxidant is carried out for a long time
to remove the hydrogen sulfide, when it has been identified as
responsible for taste and odor of water, or to remove CO2
This can reduce the demand for reactive during correction processing
(aggressiveness).
The aeration is further used to remove volatile organic materials
that are in trace amounts in water to oxidize iron and / or
manganese.
Thus, ventilation process can be defined as a physico-chemical
oxidation process because it involves the transfer of physical
phenomena of air, thus oxygen in water and optionally chemical
reactions oxidation.
In a processing unit, the ventilation practice can be simple
(aeration in a pond) or more complex (degassing tower by
stripping).
NOTES.
Cascades (waterfall):
Often these items are used to make up the differences existing
between levels on the one hand, the implementation works of the
station and also the level of the receiving environment. We took the
opportunity to artificially create a system overflows by stairs,
which has the effect of contacting water and air over a larger
surface, and thus promote the dissolution of a certain amount of air
in more efficient water that the mere transfer surface often improves
ventilation by blowing air openwork stairs.
This system also eliminates hydrogen sulfide
(odor).
Note: see in particular, on Hydro-Land site, Cascad program that
calculates a cascade in order to achieve a partial or complete
aeration of water (link, in french).
Degassing towers (stripping):
The degassing towers are towers may contain:
which will facilitate the transfer of oxygen in water, or
phenomena accelerate discharge of dissolved gases.
(According to méthose and carrier gas flow rates)
The packings are available in wide variety of plastics, ceramics or
stainless steel.
Note: see in particular, in Hydro-Land
site, DegazCO2
program that can calculate and design a
round elimination of carbon dioxide, in order to achieve a partial or
complete neutralization of aggressive water ( link
).