When multiple tanks are utilized, what proportion should the first compartment be of the total capacity?

The correct choice indicates that the first compartment of a multi-tank system should occupy between half and two-thirds of the total capacity of the tanks. This proportion is essential for ensuring optimal performance of the sewage treatment system.

Having the first compartment larger helps in effectively settling solids out of the sewage and provides adequate retention time for the liquid to begin the treatment process. This size encourages better separation of solids from liquids, reducing the load on downstream tanks and improving the overall efficiency of the system.

Choosing a proportion within this range also aligns with common practices and regulations in sewage treatment designs, ensuring proper functioning. Proper sizing of the first compartment contributes to adequate treatment of wastewater before it moves to subsequent compartments, where further treatment or polishing may take place. This principle is crucial for maintaining effective operations and compliance with environmental regulations.