The settling velocity v was determined in small 4 mL cuvettes as
well as in 1 L Imhoff cones. In the experiments with the 4 mL cuvettes,
the settling velocity (Eq. (2)) was calculated from the exponential
decrease in optical density in the cuvette over time (C0
and Ct are the optical density at the start and at time t, respectively,
and h is the distance between the top of the suspension and light
beam (Smith and Davis, 2012).