Aeration in water treatment is particularly beneficial for which of the following substances?

Aeration is a critical process in water treatment, especially for addressing certain contaminants that can affect water quality. Among the substances listed, dissolved iron and manganese are particularly amenable to aeration.

When water contains dissolved ferrous iron (Fe2+) and manganese (Mn2+), aeration serves to oxidize these ions to their respective insoluble forms: ferric iron (Fe3+) and manganic manganese (Mn4+). This transformation is essential because the oxidized forms can then precipitate out of the solution, allowing for easier removal through filtration and sedimentation processes.

The effectiveness of aeration in removing these substances is crucial since high levels of dissolved iron and manganese can lead to staining of laundry and fixtures, and they may also contribute to undesirable tastes and odors in drinking water. Therefore, aeration is employed specifically for these metals to enhance water quality.

In contrast, while phosphorus and magnesium, or phosphorus and iron are important considerations in water treatment, their removal mechanisms and the role of aeration differ. Phosphorus, for instance, typically requires biological processes or chemical precipitating agents for effective removal, not relying heavily on aeration alone.