To reduce discharging of endocrine substances into the aquatic environment, production and processing companies reduce the release of these substances by installing tech. barriers.Haupt Pharma Muenster produces hormone containing preparations such as contraceptives and was looking for a safe and environmentally friendly technol. to avoid emitting of any APIs (pharmacol. active substances).During the planning stage a conceptual design study compared four possible processes for waste water treatment: Reverse Osmosis, Activated Carbon, UV-Oxidation and disposal by a service provider.After a comparison of tech. and com. criteria, which is reproduced in this article, the company decided to use UV-oxidationThe UV-oxidation process is described, as well the daily operating practice of the UV-plant.The degradation of the hormones cyproterone acetate, letrozole, ethinylestradiol and levonorgestrel present in the waste water is shown.Either selective API degradation or a substantial mineralization of the organic matter can be achieved by the installed UV-plant in full automatic operation.The mineralization is documented by the degradation of TOC (Total Organic Carbon) and COD (COD).