The use of integrated flotation and ceramic membrane filtration for surface water treatment with high loads of suspended and dissolved organic matter

In this work, we present results of surface water treatment pilot testing of ceramic MF/UF membranes using surface water from the River Spree in Berlin, Germany. The river water is characterized by high fluctuations in quality parameters with recurring spikes in dissolved organics, turbidity and microalgae concentration. The goal of this study was to evaluate the techno-economic applicability of a novel integrated treatment process using coagulation, flocculation, induced air flotation and ceramic membrane filtration based on a 12 m3/d pilot system. It was shown that flotation serves as an effective pre-treatment for membrane filtration, allowing a flux of 112 l/m2 h with only limited and controllable fouling. Different parameters were tested in the pilot including chemical dosings, air supply, filtration fluxes etc. Turbidity and TOC levels of both the feed and the product water were continuously monitored. Finally, using an economic analysis (net present value) it is shown that ceramic membranes are comparable in overall costs to polymeric membranes or even lower when high fluxes (150 l/m2 h or higher) are implemented.