Tangential flow filtration: A method to concentrate freshwater algae

The suitability of the application of the tangential flow filtration system (TFF) for the concentration of living freshwater phytoplankton for water treatment studies was examined. We investigated the capability of a TFF system, equipped with a 0.45 μm pore-size membrane, to concentrate algae from large volumes of reservoir water characterized by low algal biomass. The samples examined were concentrated 5 to 40 times. The assessment criteria of systemsʹs performance were algal recovery rates and cell viability. It was found that large volumes of water could be processed without problems. The algal recovery was high and correlated to the applied concentration factor and the prevailing algal species. An overall algal biomass recovery of 70–89 percent was found. The assessment of algal viability in the concentrated samples was based on the growth rates and degree of preservation of their complex structure and other properties that affect their behaviour in water treatment. Algal cells in the concentrated samples and in natural reservoir water were found to be identical, with all delicate cell structures undamaged. Motile species preserved their active locomotion. Algal reproduction capacity was not affected by the concentration process. The results obtained confirm that the TFF system is a powerful apparatus for the preparation of model waters to be used in experimental algal-related water treatment studies.