In hospital as well as in surgeries a variety of substances besides pharmaceuticals are in use for medical purposes as diagnostics and disinfectants. Besides the active substances, formulation adjuvant and, in some instances, pigments and dyes are also drug components. Disinfectants, in particular, are often highly complex products or mixtures of active substances. After application, many drugs are excreted non-metabolized by the patient and enter in to wastewater