The ever-increasing use of pharmaceuticals, industrial chemicals, and hormones leads to ever-increasing water pollution. Since substances are present in surface waters in concentrations from μg/l to ng/l, they are called micropollutants. Thanks to research progress in improving analysis methods, these substances can be identified today both quantitatively and qualitatively. To maintain the good chemical status of surface waters in the future, these critical and persistent ecotoxicological substances must be removed to the greatest extent possible from wastewater.