This thesis examines the applicability of the electron beam accelerator for sewage sludge treatment with particular emphasis on the possibility of microplastics removal from liquid waste. While numerous contaminants are present in sludge, microplastics and antimicrobial – resistant bacteria are amongst the most hazardous and persistent. Unfortunately, due to pandemic restrictions, only the plastic–related research was possible to perform. The thesis explains the mechanism of the electron beam treatment and the applicability of the technique for the decomposition of newly recognised pollutants in wastewater and sludge. It makes a comparison between traditional sludge treatment techniques and the electron beam. It shows that the irradiation method is capable of removing various biological and chemical threats equally as well or better than current installations, provided that more industrial–scale facilities will be built to enable cross–referencing and standardisation. In the project that forms the basis for this thesis, the most common plastics such as PP, PE, PET, PS, PMMA and PVC have been irradiated at various doses up to 200kGy in tap water and then sewage sludge. The materials before and after the irradiation were studied by infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, gel–permeation chromatography and density flotation to determine sedimentation of powders. Additionally, high-resolution pictures have been taken using a digital microscope to observe the possible material degradation signs such as commonly reported yellowing. Additionally, the ability of microplastics to adsorb heavy metals was tested. Multiple plastics revealed various changes after the irradiation. There were effects observed such as chain scission, pigment and plasticizer removal, as well as the structure and surface modifications. The results obtained introduce the electron beam as a potential future, eco–friendly tool for microplastics modification so that they can be more efficiently removed and reused under circular economy policy.
| Date of Award | 13 May 2025 |
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| Original language | English |
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| Sponsors | European Union's Horizon 2020 Research & Innovation Programme |
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| Supervisor | Hui Cao (Main Supervisor) |
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