Two methods, centrifugation and flocculation, were evaluated to determine their efficiencies of recovery of Toxoplasma gondii oocysts from contaminated water samples. Demineralized and tap water replicates were inoculated with high numbers of sporulated or unsporulated T. gondii oocysts (1 x 10(5) and 1 x 10(4) oocysts). The strain, age, and concentration of the seeded oocysts were recorded. Oo...

Flocculation is a key unit operation in domestic and industrial water treatment, beneficiation of minerals, dewatering of sludges and in many industrial solid-liquid separation processes. Coagulants and flocculants are commonly employed as additives to induce aggregation and improve subsequent filtration or dewatering operations. The characteristics of these additives have a strong influence on...

estuaries are considered as highly dynamic ecosystem that include the mixing or transition zone between river freshwater and saline water from oceans and seas. estuaries are very important aquatic systems by preserving the coastal biota. flocculation of metals during mixing of freshwater with saline water can be considered as the most important estuarine processes. due to flocculation process, ...

Many systems contain populations of individuals. Often, they are regarded as a lumped phase, which might, for some applications, lead to inadequate model predictive power. An alternative framework, Population Balance Models, has been used here to describe such a system, activated sludge flocculation in which particle size is the property one wants to model. An important problem to solve in popu...

The combination of single cells to form doublets is regarded as the rate-limiting step of flocculation and requires the presence of surface proteins in active form. The process of activation of the flocculation proteins of yeast cells is described in the frame of the autocrine interaction regime (Science 224 (1984) 1312). The influence of several effectors (the cell efficiency to use sugars, th...

The combination of single cells to form doublets is regarded as the rate-limiting step of flocculation and requires the presence of surface proteins in active form. The process of activation of the flocculation proteins of yeast cells is described in the frame of the autocrine interaction regime (Science 224 (1984) 1312). The influence of several effectors (the cell efficiency to use sugars, th...

The principal focus of this paper is to present a critical review of current approaches to modelling the inter-related hydrodynamic, physical and chemical processes involved in the flocculation of water using Computational Fluid Dynamics (CFD). The flows inside both laboratory and full scale mechanically-mixed flocculators are complex and pose significant challenges to modellers. There exists a...