Can There be a Law of Conservation of Turbidity

Water quality models are successful in tracking the movement of various constituents through a distribution system. With some exceptions, at most nodes in a model, complete mixing occurs and the concentration after mixing can be given by a standard materials balance equation.This paper used benchtop batch mixing tests and a lab scale physical model of a water distribution system to test the hypothesis that standard water quality models based on a simple materials balance can be used to track turbidity through a water system. The results showed that as long as the components being mixed had similar concentration vs. Turbidity relationships, a materials balance was accurate but the accuracy decreased as the particle properties of the components differed.