What is the purpose of the sludge blanket in a sludge blanket clarifier?

The purpose of the sludge blanket in a sludge blanket clarifier is to act as a filtration medium through which rising water passes. The sludge blanket consists of a layer of settled, flocculated solids that helps in the clarification process. As the influent water enters the clarifier, it moves upward through the sludge blanket, where the solids can trap and remove particulates from the incoming flow. This process improves the overall efficiency of the clarifier by ensuring that the effluent water is clearer and contains fewer suspended solids, thereby enhancing the quality of the treated water released from the system.

The other options do not accurately describe the primary function of the sludge blanket. For instance, while enhancing sludge removal is a critical aspect of a clarifier's operation, it does not define the primary purpose of the sludge blanket itself. Instead, the sludge blanket's role is more focused on the filtration and clarification of the rising water. Similarly, preventing water from entering or circulating water back to the influent does not capture the essential characteristic of how the sludge blanket operates within the clarifier system.