Infoscience

Thesis

Use of light-supported oxidation processes towards microbiological and chemical contaminants elimination in hospital wastewaters

Hospital wastewaters have been long identified as carriers of chemical and microbiological pollutants. Their amounts and risk levels have initiated numerous works on changing the existing practices of co-treatment with municipal wastewaters and safe disposal in the environment. In this work, the issue of hospital wastewater treatment is studied in two different contexts, in Switzerland and in developing countries (Ivory Coast and Colombia). For this purpose, their treatment with municipal wastewater effluents is recreated, simulating the developed countries’ context, while cheap and sustainable solutions are proposed for the developing countries, to form a barrier between hospitals and receiving water bodies. In both examples, the use of Advanced Oxidation Processes is implemented, focusing on UV-based and solar-supported ones, in the respective target areas. A list of emerging contaminants and bacteria are firstly studied to provide operational and engineering details on their removal by AOPs. Fundamental mechanistic insights are provided as well on the degradation of the effluent wastewater organic matter. The use of viruses and yeasts as potential model pathogens is also accounted for, treated by the photo-Fenton process. Emphasis is given on the influence of the wastewater matrix parameters (organic matter, pH, iron speciation etc.) and the exploration of the internal oxidative events, by the use of genomic and proteomic analyses, respectively. Finally, two pharmaceutically active compound (PhAC) models of hospital and/or industrial origin are studied in wastewater and urine, treated by all accounted AOPs, as a proposed method to effectively control concentrated point-source pollution from industrial and hospital wastewaters, respectively. Their elimination was modeled and the degradation pathway was elucidated by the use of state-of-the-art analytical techniques (TOF-MS, Orbitrap). The use of light-supported AOPs was proven to be effective in degrading the respective target and further insights were provided by each application, which could facilitate their divulgation and potential application in the field.

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