In this theme, the focus is on developing natural alternatives for synthetic organic polymeric flocculants for the treatment of surface water or wastewater. These alternative flocculants should overcome the disadvantages of synthetic polymers: produced from scarce fossil sources, non-specific, non-biodegradable, and produce large amounts of (toxic) waste that cannot be reused in, e.g., agriculture. Mixed extracellular polymers produced by micro-organisms during biological wastewater treatment are more sustainable than synthetic polymers, and indications are that they can also give a better flocculation performance.
Moreover, possibly in combination with physical separation technology such as membrane treatment, natural flocculants have a potential application to remove particles in drinking water, to produce industrial process water from fresh or saline surface and waste waters, to treat oil-containing wastewaters, to separate algae from their medium in algae cultivation systems, to assist in the retention of valuable biomass in biological wastewater treatment processes, etc. The theme started in 2004.