What are the two types of aeration in water treatment?

The correct answer highlights the two primary types of aeration used in water treatment: stacked tray and diffused aeration.

Stacked tray aeration involves the use of a series of trays that are stacked vertically. Water flows over these trays, and as it does so, air is introduced, allowing for efficient mixing and transfer of oxygen into the water. This method facilitates the removal of volatile compounds and improves the overall water quality.

Diffused aeration, on the other hand, utilizes air diffusers that are placed at the bottom of a treatment basin. These diffusers release fine bubbles of air into the water. The bubbles rise to the surface, providing a large surface area for the transfer of oxygen into the water. This method is particularly effective in promoting biological processes such as those carried out by aerobic microorganisms.

Understanding these two aeration types is crucial as each serves specific purposes in enhancing water quality and supporting biological treatment processes in wastewater treatment facilities. Other options, while they may reference different forms of aeration, do not encompass the two main types traditionally recognized and applied in water treatment practice.