Analysis of flocculation in a jet clarifier. Part 2 - Analysis of aggregate size distribution versus Camp number

Abstract Among the various existing technologies for water treatment, the jet clarifier is considered as an effective and compact system as it couples flocculation and clarification in a single unit. In this work, a quasi-two-dimensional apparatus was designed to visualise the interaction between floc size distribution and hydrodynamics in the flocculation zone of a jet clarifier. Measurements of the number of flocs and their size distributions are performed by means of shadowgraphy method and image analysis. Thanks to a coupling between population size distributions and results on local hydrodynamics, the evolution of the number of aggregates along the jet is directly correlated to the recirculation loop present in the flocculation zone. The relative independence of the floc size distributions on the flow rate is discussed in light of the Camp number Gt which remains constant for different flow rates investigated and can thus explain the efficiency of the jet clarifier in terms of flocculation.