On the development of a high rate deep bed filtration unit

Dispersed water contaminants with diameters less than 50 μm usually carry the greatest burden of contaminants that are of potential concern to the environment and human health in sewage. Microorganisms and viruses can be counted to this group of contaminants for instance. Furthermore, colloidal water contaminants possess a higher specific surface area per unit mass which can enable the accumulation of possibly problematic dissolved water contaminants onto this area. Therefore, efficient removal of contaminants from wastewater relies on the efficient removal of fine particles and colloidal material from water. The CSIRO Molecular Science has been developing the idea of using high rate deep bed filtration through porous plastic media to improve the separation of suspended and colloidal particles from sewage. Because the IWW was aspiring an analogous technology by developing and modelling deep bed filtration with permeable synthetic collectors (PSC), the possibility for collaboration in a research project was given. The project investigated the use of a dual stage filter media system with upwards directed flow. The aim of using this system was to achieve high total suspended solids (TSS) removals and high turbidity storage capacities at fast filtration rates (20-50 m/h) while simultaneous decreasing the dose of flocculation chemicals to its minimum.