Elimination of Diethylenetriaminepentaacetic Acid from Effluents from Pharmaceutical Production by Ozonation

During production of diethylenetriaminepentaacetic acid (DTPA), process waste water is generated in several production stages. Process wastewater is usually disposed of via waste water treatment plants. However, due to low biodegradability of DTPA in conventional waste water treatment, incineration constitutes the current method of choice. The main disadvantage of incineration is high consumption of primary energy sources leading to substantial emission of carbon dioxide (CO2). Thus, an alternative method of process waste water treatment was investigated, which consists of an initial application of ozone and a subsequent biological treatment. In 2009, preliminary laboratory experiments were conducted to evaluate the elimination of DTPA in process waste water. Based on the initial results, the responsible authorities granted approval for large-scale ozonation of DTPA-containing wastewater in 2011. Additional laboratory scale experiments were carried out to assess the elimination of the target compound and the generation of its main transformation products using liquid chromatography – high resolution mass spectrometry. Through application of the postulated method, the concentration of DTPA and its derivatives can be reduced to levels assuring safe discharge into the receiving water. Additionally, a comparison of CO2 emissions showed that ozonation is an ecological alternative to incineration and, most likely, an economical as well, based on the local prices of primary energy sources.