What is the best position to install the lamellar modules in a settler?
posted in Technical Articles by TecnoConverting
A common question when a lamellar settler is sized is what´s the correct position to install the lamellas in the equipment. In other words, what direction shall be the inclination of the lamellar modules, in the flow or cross flow direction?
The answer is: If a lamellar settler is sized to work as a DAF, ie favoring the separation of floating particles, it is best that the inclination is on the same direction of the flow, as flow velocity helps suspended particles to ascend faster.
Conversely, a lamellar settler is being sized to be the most efficient in sedimentation, then the inclination of the lamellas has to be installed in cross flow direction to avoid that the flow ascends directly the solid particles.
It is also interesting to know this lamellar position (in cross flow) helps mitigate the effect of the corrected Hazen speed (or corrected ascendant speed) , and also the lamellar works as deflector so the inlet becomes slower.
On the images below from our simulation model, you can see how preferential channels are generated due to the inflow streamline. Here it´s clearly appreciated how the lamellar inclination helps the particles to descend more quickly.
