What is the typical removal efficiency of settleable solids in a primary clarifier?

The typical removal efficiency of settleable solids in a primary clarifier is generally around 95 to 99 percent. This high removal rate is achieved through the process of sedimentation, where heavier solids settle to the bottom of the clarifier due to gravity.

Primary clarifiers are designed to effectively separate solids from the wastewater during the initial treatment stage. The design and operation of these clarifiers are optimized to promote settling by allowing sufficient retention time for the solids to accumulate and sink.

While some lower removal efficiencies might occur under less than ideal conditions, such as rapid flow rates or excessive solids loading, the standard range reflects the capability of properly functioning primary clarifiers to significantly reduce the concentration of settleable solids. This efficiency is crucial for minimizing the organic and nutrient loading on subsequent treatment processes, such as biological treatment systems.