A clarifier is provided with an improved inlet structure which receives influent from influent column ports and discharges the influent uniformly around the entire circumference of the inlet structure. The influent column ports may be baffled. Angled guide vanes on the inlet structure reduce the flow energy and effect a tangential flow into a feedwell in the basin. The feedwell may be conical to further reduce the velocities and create an outward flow to counteract inward flows in the basin.