With the start of the PhD project of Bram Mulling, the department of Aquatic Ecology and Ecotoxicology of the University of Amsterdam (IBED-AEE), the Foundation for Applied Water Research (STOWA), Waternet and Witteveen en Bos started a formal cooperation focussed on waterquality improvements of effluents by biological filtration systems. In the past years, these filtration systems are installed at several sewage treatment plants in the Netherlands, on both experimental and semi-full scale within the framework of the ‘Waterharmonica' concept, describing the role of biology between effluent and surface waters. These biological systems are designed to reduce the levels of nutrients, particles, pathogens and contaminants from treated wastewater. Experiments with effluent polished by the ‘waterharmonica' system have shown promising results in improving the water quality to a level equal or even better than receiving, natural waterbodies. However, the processes that cause the observed water quality improvement of effluent by the ‘waterharmonica' system are not well understood. One of the black boxes in the system is the conversion of particles (including pathogens).  Therefore, this new team of experts is established, aiming to gain a better understanding of the processes within the ‘waterharmonica' that convert particle composition and neutralize pathogens.
By optimizing the ‘waterharmonica' system the transformation from treated waste water into good quality water could make the ‘waterharmonica' system interesting for parties in need of good quality water (drinking water production, inflow into nature reserves).