What happens upstream of the membrane during a filtration process?

And what do cakes have to do with purifying water?
 Quite a lot...

 Whether in water treatment (e.g. municipal wastewater reuse) or in food processing to remove microorganisms, proteins and bacterial and protozoan pathogens, microfiltration and ultrafiltration are common processes and an important part of the purification process.

 However, one of the most common and persistent challenges in membrane filtration processes is the reduction of the flow rate due to membrane fouling and the formation of a so-called filter cake in front of the membrane. This is not without consequences: The filter cake that accumulates on the membrane surface represents an additional hydraulic resistance for the entire process and increases the energy required for separation. This also reduces the overall efficiency of the process.

Lucas Stüwe, Arne Lüken, Felix Stockmeier, Lukas Griesberg, Timon Kratzenberg, John Linkhorst, Walter Richtering and Matthias Wessling have taken a major step towards clarifying important questions such as "What actually happens upstream of the membrane during a filtration process?" and thus make an important contribution to understanding the behavior of soft particles during these processes.

In this paper published in the Journal of Membrane Science, based on the research of the Collaborative Research Center (CRC) 985 "Functional Microgels and Microgel Systems" (funded by the German Research Foundation (DFG)), Matthias Wessling and DWI Associate Scientist Walter Richtering combined their expertise.