Surface and sieve filtration are the dominant separation mechanisms in clarifying filtration, where large amounts of liquids need to be cleaned from small amounts of particular contaminants, while achieving high volumetric throughputs. In common cake filtration, these blocking mechanisms are only happening during the initial stages of filtration and are rarely relevant to the process. This is why the process of clarifying filtration has been studied very little in the past.
In automatic filters, filter candles are continuously cleaned by backwashing the filter medium with filtrate. The cleanability of the filter medium depends on the medium geometry as well as the separated particulate matter. There is no precise statement in literature whether the pressure pulse or the maximum pressure is the relevant parameter for cleaning efficiency. Furthermore, unlike in gas cleaning, there exist no standards for the evaluation of backwashable media in liquid filtration.
Within the framework of an industry-advised research project, a new experimental filtration apparatus was developed in which a planar filter medium can be backwashed repeatedly, after a specified criterion is reached. The new laboratory rig makes it possible to evaluate different filter media for their suitability as a filter medium in automatic backwash filters...
Session: L17 - Backwashing Filtration
Day: 24 October 2019
Time: 13:00 - 14:15 h