Where is floatable scum typically removed in the wastewater treatment process?

Floatable scum is typically removed in the primary clarifier during the wastewater treatment process. The primary clarifier is designed to settle out solids and remove floatable materials, such as oils, fats, and greases, as well as any suspended solids present in the wastewater. This unit uses gravity to facilitate the separation of solids from the liquid, allowing the lighter materials to rise to the surface and form a scum layer, which can then be mechanically skimmed off.

The primary clarifier is crucial for reducing the organic load on downstream treatment processes and improving overall water quality. By removing floatable scum at this stage, it helps to prevent these materials from causing problems in subsequent treatment stages, such as clogging aeration tanks or affecting biological processes in secondary treatment. This is why primary clarification is specifically designed to target and eliminate such contaminants efficiently.