Simulations describing the settling of suspensions of solid particles bounded by a rigid container are presented. Results are compared with previous simulations of homogeneous suspensions with periodic boundary conditions. Velocity fluctuations in vertically inhomogeneous suspensions are found to saturate under conditions similar to those found in laboratory experiments, while in vertically hom...

A new one-dimensional clarifier model was developed, including components of existing models, and extended with a height-dependent cross-sectional area and two flowrate-dependent dispersion coefficients. This model is evaluated using data from a detailed one-month measuring campaign on a full-scale wastewater treatment plant. The data included hourly sludge concentration profiles, sludge bed he...

Sediment profiles in open channels are usually predicted by advection-diffusion models. Most basic forms consider the terminal settling velocity of a single particle in still clear water. Alternative forms account for hindered settling at higher concentrations. It is not known, however, how these modifications relate to mass and momentum conservation of each phase. For dilute flow, it is known ...

In the context of wastewater treatment with microalgae cultures, coagulation-flocculation followed by sedimentation is one of the suitable options for microalgae harvesting. This process is enabled by the addition of chemicals (e.g. iron). However, in a biorefinery perspective, it is important to avoid possible contamination of downstream products caused by chemicals addition. The aim of this s...

Novel flocculants have been synthesized on the basis of glycogen. The efficiency of cationic glycogen can be explained in terms of Singh’s qualitative easy approachability model (EAM). The jar test was used previously to evaluate flocculation efficacy, but we have recently shown that a plot of interface height vs. settling times provides a better measure. In accord with the EAM, a one-to-one co...

Direct imaging of settling, non-Brownian, hard sphere, particles allows measurement of particle occupancy statistics as a function of time and sampling volume dimension. Initially random relative particle number fluctuations, (2)>/ = 1, become suppressed, anisotropic, and dependent. Fitting to a simple Gaussian pair correlation model suggests a minute long ranged correlation leads...