Different advanced wastewater treatment processes have proven to render persistent and even toxic intermediates, so disappearance of the parent contaminant does not imply that the treatment was efficient. Considering the potential hazards of by-products generated during treatment, their identification and quantification, as well as elucidation of main reaction mechanisms, are necessary for the safe application of such processes for wastewater treatment. The main objective of this ESR is to elucidate transformation pathways and identify structures of main transformation products (TPs) from selected emerging microcontaminants formed during treatments studied in PhD project 1 (BioMAC, MBR, Bioaugmentation, AOP and BES) and evaluate potential ecotoxicological effects of intermediate TPs. In addition, aim is to get better insight into transformation processes during treatment, such as deconjugation (relevant for hormones and pharmaceuticals) and chiral transformations (pharmaceuticals and their metabolites). The tentative list of target emerging microcontaminants includes those on the watch list of EU WFD (diclofenac, estradiol, ethynilestradiol), other pharmaceuticals identified as having high potential to enter the environment and so far not studied in wastewater treatment processes (levotyroxine, alendronic acid, topiramate, pioglitazone, telmisartan pregabalin and quetiapine). Additionally, other microcontaminants will be considered in a prioritisation exercise performed with the aim to quantify the risk of hazardous compounds using GIS based risk assessment. Acute and chronic toxicity of TPs and mixtures will be determined at the different stages of the treatment using in-vitro assays (Vibrio fisheri, Scenedesmus, Daphnia, and Zebra fish).
The ESR will learn about the identification of main TPs formed during wastewater treatment for selected emerging contaminant and will have deep knowledge on mechanisms governing transformation of contaminants, including deconjugation and chiral transformations. The candidate will become an expert on the potential toxicity of the parent compounds and their TPs at the different stages of treatment and will come up with relationships between operational parameters and contaminants’ removal including total mineralization, and partial transformations.