In situ real-time monitoring techniques for membrane fouling in food, biorefinery and biotechnology industries

Membrane fouling is a constant challenge of membrane processes in separation and purification of organic, biomass originated compounds in food, biorefining and biotechnology industries. It persists due to the complexity and high fouling tendency of the bio-based streams and may result in a decrease of filtration capacity, rejection alteration, reduction of membrane lifetime and increase of operational costs. Hence effective fouling prevention strategies are highly desired. Conventional fouling monitoring and control methods are often based on process performance or product quality, usually revealing membrane fouling after it occurred in a severe and non-reversible way. Thus, in situ real-time monitoring techniques are required providing early warning about extent, quality and distribution of foulants accumulated on the membrane surface in order to reach one of the ultimate goals in the development of membrane based technologies - a non- or controlled-fouling process with a steady flux and retention. Despite the evident advantages of different real-time monitoring tools, adaptation of them in fouling-concerned food, biorefining and biotechnology industries has not been widely published. Hence, this work compares advantages and disadvantage, as well as aims to investigate potential uses of in situ real-time membrane fouling monitoring techniques in the field of these industries. Different in situ real-time techniques are presented and their characteristics highlighted. Emerging techniques are identified and a future perspective is discussed.