What does aeration remove from water? In water treatment, aeration primarily accomplishes the removal of which constituent class?

Introduction / Context:
Aeration involves intimate contact between water and air, typically by spraying, diffused aeration, or cascade towers. It is an important pretreatment step for taste and odour control, corrosion mitigation, and removal of undesirable gases.

Given Data / Assumptions:

• Typical raw groundwater or surface water with dissolved gases (e.g., CO2, H2S) present.
• Standard municipal-scale aeration equipment.

Concept / Approach:
Aeration strips volatile dissolved gases by mass transfer to the air phase and can also oxidise certain species (e.g., Fe2+ to Fe3+). It is not a primary method for removing suspended solids (settling/filtration are used) or dissolved solids (which require ion exchange, RO, or precipitation).

Step-by-Step Solution:

Verification / Alternative check:
Design guides state aeration effectiveness for degassing and oxidation; turbidity removal relies on settling/filtration, not aeration alone.

Why Other Options Are Wrong:

Common Pitfalls:
Assuming aeration meaningfully lowers TDS; it does not, except for removal of volatile components that contribute little to TDS.

Final Answer:
dissolved gases