A phenomenological retention tank model using settling velocity distributions

Many authors have observed the influence of the settling velocity distribution on the sedimentation process in retention tanks. However, the pollutants’ behaviour in such tanks is not well characterized, especially with respect to their settling velocity distribution. This paper presents a phenomenological modelling study dealing with the way by which the settling velocity distribution of particles in combined sewage changes between entering and leaving an off-line retention tank. The work starts from a previously published model (Lessard and Beck, 1991) which is first implemented in a wastewater management modelling software, to be then tested with full-scale field data for the first time. Next, its performance is improved by integrating the particle settling velocity distribution and adding a description of the resuspension due to pumping for emptying the tank. Finally, the potential of the improved model is demonstrated by comparing the results for one more rain event.

Figure optionsDownload high-quality image (270 K)Download as PowerPoint slideHighlights
► A published dynamic retention tank model has been confronted with full-scale field data for the first time.
► A new phenomenological retention tank model simulating TSS behaviour is proposed.
► Its performance is validated by comparing results with full-scale data.
► Using settling velocities of particles improves simulation results in water quality modeling under storm weather conditions.