A top-loading settling column is described and used to characterize the settling properties of the solids in the discharge water from a commercial rainbow trout production facility. Mass-based and phosphorus-based settling curves are presented. The median settling velocity on a mass-basis for the settleable solids was 1.7 cm s. The median settling velocity for the settleable phosphorus was 1.15...

An analytical solution of the equilibrium distribution of suspended sediment concentrations (SSC) in an estuary along the longitudinal axis is extended to include variable width. A turbidity maximum is formed at the convergence of fluxes from freshwater discharge and (vertically well mixed) salinity gradients. Simple scaling relationships control the longitudinal distribution of SSC and depend ...

It is well known that the permeability and density of an aggregate decreases with its size, affecting its settling velocity and coagulation rate (rate of particle capture) with other particles. This change in aggregate density with size can be described by fractal scaling relationships. Two distinctly different fractal scaling approaches, however, have been used to describe aggregate permeabili...

The results of batch settling tests (BST) are used to investigate settling behavior of solids suspension, which contribute to sizing thickeners. Conventional methods in analyzing BST on the basis of visual and graphical procedures lead to sub-optimally sized and selected thickeners. A computational approach based on quantitative analysis of BST can be beneficial. About 300 settling experiments ...

The objective of this work was to assess the impact of filamentous bacteria on the settling velocity and rheological behaviour of activated sludge. We then identified the relevant settling and rheological model parameters to account for the impact of filamentous bulking on the prediction of sludge mixing and transport in secondary settling tanks by a computational fluid dynamics (CFD) model. We...

Secondary settling tanks (SSTs) are the most hydraulically sensitive unit operations in biological wastewater treatment plants. The maximum permissible inflow to the plant depends on the efficiency of SSTs in separating and thickening the activated sludge. The flow conditions and solids distribution in SSTs can be predicted using computational fluid dynamics (CFD) tools. Despite extensive studi...

Given the relative simplicity of all simulation models in comparison to the complexity of nature, it seems reasonable to question the legitimacy of any "mechanistic" mathematical description of surface water quality. Further, given data limitations and scientific knowledge limitations, it seems reasonable to question even the goal to strive for a model that need not be calibrated. The correctne...

Finite settling time control of the double integrator is considered. The approach taken is to design a compensator based on a virtual lossless absorber which is tuned so that, at some predetermined time, the virtual subsystem possesses all of the system’s energy. At this time the controller is turned off, and the double integrator remains at rest at the origin. This strategy gives the appearanc...

In this research work, the parameters affecting the settling velocity within the thickeners were studied by introducing an equivalent shape factor. Several thickener feed samples of different densities including copper, lead and zinc, and coal were prepared. The settling tests were performed on the samples, and the corresponding settling curves were plotted. Using the linear regression analysis...