Interpretation of radiotracer experiments in an industrial battery of desanders with simultaneous stochastic and non-stochastic flows

Radiotracer experiments have been conducted in an industrial battery of twelve desanders located at the water treatment plant of Lima. The flow behavior is complex because it includes the superposition of a stochastic flow, which is intrinsic to the process itself, and of a non-stochastic flow induced by local strong currents at the surface. These currents are non-stochastic because they are different from one desander to another one even if all the desanders are identical. A general model has been proposed to simulate the whole behavior of the process. The model is composed of two parts: the first one, describes the stochastic flow behavior, and is the same for each desander; the second one is adapted to represent the turbulent shortcuts at the surface of each desander. The parameters of stochastic part have been determined to be consistent with the physical description of the process. The value of the Peclet number of the shortcut is a monotonic function of the flow rate. Despite remaining uncertainties due both to the complexity of the flow and to specific problems of tracer measurements in large industrial water treatment plant, this paper proposes an extension of the applications of radiotracer experiments and interpretation.