A promising optical technique to measure cake thickness of biological particles during a filtration process

This work aims to test an in situ optical measurement method of the thickness of a biological particle cake built on a mineral membrane. This method uses a photointerrupt sensor. It is a low-cost, direct and non-destructive method. The measurement method was tested in a model system which consists of a settlement of baker yeast on a plane membrane surface. Both a commercial membrane and a home-made red mineral membrane made of sintered clay were used in these preliminary experiments. The sensitivity, valid range, precision, and accuracy were first studied. Then, the effects of membrane colour, slurry concentration and background light on the measurement were investigated. Finally, the method was applied to a filtration process of a yeast saccharomyces cerevisiae suspension.