(4d) Influence of Filter Cake Thickness during Backwash Regeneration
With respect to the field of applications, the removal procedure has revealed that there is potential for improvement. A properly regenerated filter cloth highly depends on the interaction between the particle system and the filter cloth (weave type, thread thickness, material). In order to guarantee the removal of the filter cake, the applied removal force has to be larger than the adhesive forces. Furthermore, to remove the filter cake in large fragments, the removal force has to be lower than the cohesive force. These two effects also depend on the porosity of the filter, pH-value, and further properties.
Currently, the boundary conditions for a properly regenerated filter cloth has not been investigated effectively. Hence, further research must be carried out to improve the backwash treatment with respect to the process conditions in an economic and process-technical context.
This presentation shows the influence of cake thickness on the discharge during backwash filtration. For this, different types of cake discharge will be described. Furthermore, the project and experimental facility will be presented.
Figure 1: Filtrate-Time-Diagrams and schematic representation of process management with properly regenerated filter cloth (a) and improperly regenerated filter cloth (b). In case of the properly regenerated filter, the filtrate flow at the beginning of each filtration step is equal. In case of an improperly regenerated filter, the filtrate flow decreases as a result of the remaining filter cake fragments on the filter cloth surface.