What percentage of suspended solid removal can be achieved without chemical addition in primary clarification?

In primary clarification, the process primarily relies on physical separation mechanisms rather than chemical reactions, which allow for the removal of suspended solids from wastewater. Typically, primary clarifiers are designed to facilitate gravity separation, where solids settle to the bottom of the tank, forming sludge, while lighter materials, including oils and greases, rise to the surface as scum.

Achieving a suspended solid removal percentage of 50% to 65% is consistent with what is commonly expected in primary clarification processes without the use of chemical additives. This range reflects the effectiveness of physical processes such as sedimentation in removing particles that are large enough or dense enough to settle out.

While higher removal rates can be achieved with enhanced treatment methods or the addition of chemicals for coagulation and flocculation, these methods are not utilized in conventional primary clarification without chemicals. Therefore, the range of 50% to 65% accurately portrays the capability of primary clarifiers under typical operational conditions, emphasizing that while effective, primary clarification has its limits concerning the overall removal efficiency of suspended solids.