Tangential filtration of microbial suspensions: filtration resistances and model development

Harvesting of microbial cells by tangential filtration was investigated with well defined Escherichia coli and baker's yeast media. Parameters responsible for the sublayer formation at the membrane surface were studied in detail using two self-constructed modules of tube and flat channel configurations respectively and different types of membranes. The deposited mass and filtration resistance of the sublayers formed were analysed. Results show that layer heights (amounts deposited) decrease with increasing channel length due to the pressure drop behaviour of the modules. Layer heights between 0.5 and 40 μm were determined. The filtration resistance of the layers was found to be higher than the resistance of corresponding ‘cakes’ formed in static filtration. A simple empirically derived model was developed which can be used to calculate filtration performance over the range of experimental conditions studied.