Nitrate concentrations of our groundwater are among the highest in the European Union. The main reason is over-fertilization of fields with feces from livestock farming. Every year, a “liquid manure shower” of 200 million tons goes down onto German fields, the result being too high nitrate levels at one third of the groundwater quality measurement points. Researchers of Karlsruhe Institute of Technology (KIT), together with the Foundation for the Environment of Rhineland-Palatinate and an environmental engineering office, are working on a very simple process for the large-scale cleaning of polluted drainage water from agricultural areas.