Does a step-down system require the first "leg" to be flooded or failed before the next leg receives wastewater?

A step-down system is designed to manage wastewater in a way that optimizes the flow through various stages or components. In this context, the first "leg" of the system must indeed be filled or flooded before the subsequent leg can receive wastewater. This configuration ensures that the system functions effectively, allowing for proper treatment and distribution of wastewater.

When the first leg reaches a certain capacity, it signifies that it is ready to pass the effluent onto the next leg in the system. This sequential flow is crucial because it allows for the treatment process to occur in stages, where each leg can handle a specific amount of wastewater, providing a more efficient and controlled treatment of the waste.

Other options address scenarios or systems that may not require the first leg to be flooded before proceeding, such as gravity-fed systems or aerated treatment units (ATUs), but in the context of a traditional step-down system, ensuring that the first leg is flooded or has reached its capacity before the next leg receives effluent is a fundamental operational principle. This mechanism contributes to the overall efficiency and reliability of the wastewater management process.