What is an appropriate action to take if grease removal efficiency needs improvement in a primary settling tank?

Implementing preaeration is an effective action to improve grease removal efficiency in a primary settling tank. Preaeration involves introducing air into the wastewater before it enters the settling tank. This process helps promote the aggregation of grease and other floating materials, making it easier for them to rise to the surface where they can be skimmed off. By increasing the amount of air in the tank, grease particles can coalesce, which enhances their buoyancy and allows for more efficient removal.

In contrast, increasing chemical dosing might not specifically target grease removal effectiveness and could lead to other chemical management issues. Decreasing tank depth could potentially reduce retention time and may not allow sufficient time for grease to separate properly. Modifying inflow rates could disrupt the settling process and potentially lead to increased turbulence, which can hinder the separation of grease from the wastewater. Thus, preaeration stands out as a targeted method to effectively address grease removal in a primary settling tank.