Research field The focus of his research at KWR and TUDelft is the provision of a scientific basis for microbial risk management for the Dutch drinking water utilities and other stakeholders in the water sector. This encompasses: development of methods for detection/typing/source tracking of faecal pathogens in water, soil, aerosols studying the occurrence of these pathogens in the water cycle (wastewater, surface water, groundwater, drinking water, aerosols) studying the transport of pathogens in water bodies (modelling) studying transport of micro-organisms in the subsurface (bank filtration, infiltration, groundwater abstraction) assessment of the removal of micro-organisms by water treatment processes, both conventional and advanced (membrane filtration, UV, advanced oxidation) incorporating this knowledge into quantitative risk assessment/health impact assessment advising risk management