Aeration oxidizes which two elements to form insoluble precipitates?

Aeration is a crucial process in water treatment that aids in the removal of certain dissolved elements by promoting their oxidation. In the context of the question, aeration specifically oxidizes iron and manganese, which are commonly found in groundwater and can lead to various issues such as staining and taste problems.

When iron and manganese are oxidized during the aeration process, they transition from their soluble ferrous (Fe2+) and manganous (Mn2+) forms to their insoluble ferric (Fe3+) and manganic (Mn4+) forms, respectively. These insoluble precipitates can then be effectively removed through processes such as sedimentation or filtration.

The relevance of this oxidation process is significant in ensuring the quality of drinking water, as high concentrations of dissolved iron and manganese can not only cause aesthetic concerns but can also be problematic for plumbing systems and water treatment facilities. Therefore, the correct answer focuses on the critical elements that aeration directly affects and precipitates out of solution.