Aeration and Other Methods for Removal of Dissolved Gases
The process of aeration is used to improve the physical and chemical characteristics
of water for domestic use. The more important functions of this process
are the removal of dissolved gases, such as carbon dioxide, methane, and
hydrogen sulfide, and the addition of oxygen necessary for the precipitation
of iron and manganese. However, oxygen entering the water may increase
its corrosiveness. If organic matter is not present, aeration alone is
sufficient to cause precipitation of iron and manganese. Aeration can also
partially remove volatile substances causing problems with odor and taste.
However, since some substances are not sufficiently volatile, aeration
is not always efficient in the removal of odor and taste. The use of aeration
should not be considered if water would be subjected to airborne contamination.
Other methods of oxidation can be used for removal of dissolved gases
like hydrogen sulfide. Oxidation is necessary for conversion of the gas
to forms which can precipitate and therefore be filtered. It can be done
using oxidizing filters (green sand filters), chlorination, or treatment
with hydrogen peroxide, which has been tested lately for this purpose.