Prediction of Suspension Turbidities from Aggregate Size Distribution

The turbidity of a coagulating, but noncoalescing, suspension cannot be determined directly because of interference between scattered waves and phase shifts in transmitted waves. This research developed a "coalesced-sphere" light scattering model which was applied to a noncoalescing, coagulating system to predict, within reasonable limits, the suspension turbidity. The application of the coalesced-sphere model for aggregates in the Mie scattering regime allows the calculation of the turbidity per size interval caused by particulates in the coagulated suspension. Knowledge of the turbidity fraction can lead to improved design of phase-separation devices, such as water and wastewater filters, so they remove the portion of the size distribution that contributes most significantly to the overall suspension turbidity.