Distribution of retention times in model biological filters containing packed spheres

Abstract In this paper, a theory developed for computing flow time using the velocity equation of the laminar regime was experimentally verified and the ranges of validity of dispersed plug flow and mixed flow were determined to compute the retention time. Mean residence time when plotted vs hydraulic loading on a log-log paper provides straight lines. In this paper their equation was theoretically derived. To reach this result the hydraulics of falling films and jets was used.