By definition, “oxidation” is the loss of electrons from a reducing agent. We commonly use the phrase “the process has been oxidized”. Electrons carry negative charges and the oxidation process results in an increase of positive valence. Oxidation reduces the number of electrons orbiting any specific element which in turn causes the element to bond with oxygen when there is oxygen present because it has an attraction for those electrons.
In water iron can be present in several forms but the most commonly found iron is in its soluble state as ferrous bicarbonate (C2H4FeO6). Ferrous iron has a positive two valence. As ferrous iron is oxidized, the number of electrons will be reduced and the iron develops a valence of positive three, ferric hydroxide, Fe(OH)3. The most cost effective way to oxidize iron in water is to fully aerate the water utilizing an “aeration tower”. The aerator is very similar to a degasification tower or air stripper as it utilizes either forced draft or induced draft air movement to create the enriched oxygen environment needed. Typically the aerator will rely upon the “impingement process” to reshape the water molecules and expose the iron to oxygen in order to force the electrons to flow and thus the iron to oxidize.
Aerator towers are made from either fiberglass or aluminum material and have a life expectancy exceeding 30 years if properly maintained. An aerator tower is much more efficient than a diffuser or air compressor since the water is constantly reshaped, exposing the iron to oxygen by utilizing the media bed. The media bed of an Aerator may vary depending upon the Iron concentration and anticipated fouling rate. DeLoach Industries utilizes a proprietary slat tray media that sheds iron fouling and reduces maintenance periods. Other towers will utilize random packing, but this type of packing in an iron oxidation process can be problematic and expensive; from the need to clean and replacement of the packing.
The amount of dissolved oxygen required to fully oxidize iron must be at least 15% of the total amount of iron present. An Aeration tower creates sufficient oxygen and when both are present the iron and oxygen bond together. As long as the water is not acidic the soluble ferrous bicarbonate can completely oxidize and change to the insoluble ferric hydroxide precipitate, Fe (OH) 3. For more information or to learn more contact the professionals at DeLoach Industries Inc. at (941) 371-4995.
Receive Your Free Odor Control E-Book