What does iron oxidation mean in practice?
Dissolved Fe2+ is converted to Fe3+ forms, which hydrolyze and create particles that can be filtered.
When does it matter?
The reaction rate depends strongly on pH, oxidant dose and contact time, so aeration alone may be insufficient.
Which solutions are related to it?
Oxygen, chlorine, permanganate or other oxidants matched to the water chemistry are used, followed by filtration and control of residual iron.