Flocculation phenomena in dispersions

Location: Department of Environmental Fluid Mechanics of the Delft Technical University (TU Delft).

Supervisors: Erik van der Linden (erik.vanderlinden@wur.nl) and Claire Chassagne (C.Chassagne@tudelft.nl).

In many food products flocculation is a widespread phenomenon that requires control. There is a possibility to learn more on flocculation phenomena in dispersions via a thesis topic at Delft university. The hosting group in Delft is investigating the relation between the composition of clayey suspensions and slurries and their physical properties, such as viscosity, settling of clay aggregates (flocs) or consolidation of formed beds. One part of the research is devoted to the study the flocculation of clay particles by polymers. In a first step, synthetic polymers (cationic and anionic) have been used, leading to the development of a new flocculation model. This model links the growth of flocs in time to the properties of added polymers and the shear stress applied to the system.

In a second step, the group aims to test the model by using polymers that can be found in natural environments, in for instance lakes or estuarine regions. The work of the student will consist of:

• identifying the relevant polymers in natural environment by an extensive literature survey
• performing a series of flocculation experiments using either these polymers or synthetic polymers that best mimic the natural polymers, in the conditions found in these natural systems (same shear stress, pH, ionic strength, temperature …)
• testing and refine the new flocculation model with the findings
• reporting the results

The work will actually be performed at Deltares (http://www.deltares.nl/) in Delft. Deltares is an independent, institute for applied research in the field of water, subsurface and infrastructure. A small financial compensation will be awarded to the student during the period of his stage.