What is the function of a primary clarifier in a wastewater treatment plant?

The function of a primary clarifier in a wastewater treatment plant is to remove settleable organic and inorganic solids from the influent wastewater. During the primary treatment phase, wastewater flows into the clarifier where it is allowed to settle. The heavier solids are separated and sink to the bottom, forming a sludge blanket, while the lighter materials, including oils and greases, may float to the top and form a scum layer. This process significantly reduces the concentration of suspended solids and organic matter before the water moves on to secondary treatment processes. By effectively removing these solids, primary clarifiers help to improve the efficiency and effectiveness of downstream treatment processes, ensuring that the overall system operates more efficiently. The other options provided focus on different aspects of wastewater treatment that are not functions of the primary clarifier.