Civil Engineering PE

Answer: B - The statement, “Sizing is based on the measured flow conditions” is not correct when considering the surface overflow rates of primary settling tanks. Typically, the primary settling tanks are sized based on the surface area calculations performed using 1) design average flow conditions and 2) design peak hourly flow conditions. The larger surface area of the two is used to size the primary setting tank. Specific design requirements for primary settling tanks are set by state regulating agencies.