Final answer:
Aerating the wastewater before primary clarification supplies oxygen to bacteria, enhancing the breakdown of organic contaminants including grease, which in turn improves the efficiency of grease removal during clarification.
Step-by-step explanation:
Aerating the wastewater before the primary clarification process assists in the removal of grease and other organic matter.
During aeration, air is bubbled through or sprayed into the wastewater, supplying oxygen to microorganisms. These microorganisms, such as aerobic bacteria, help to break down contaminants in the water.
When the aerated effluent is passed to the secondary clarifier, this decomposition continues, allowing for microorganisms and remaining solids, including grease, to settle out as activated sludge.
The process of aeration prior to the primary clarifier means that much of the grease and organic contaminants are already being addressed by microorganisms, enhancing the overall efficiency of the grease removal in the subsequent clarification stage.