Effekten av fotoreaktivering og partikkelinnhold ved UV-desinfeksjon av renset avløpsvann
Master thesis
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https://hdl.handle.net/11250/3021450Utgivelsesdato
2022Metadata
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Sammendrag
UV-disinfection as a treatment method is well suited for wastewater treatment plants of mediumsize or smaller and is an effective way to inactivate microorganisms. However, the treatmentmethod is dependent on factors related to the quality of the water, which must be properly treatedbefore disinfection. Its’ effectiveness may also be affected by photoreactivation, which is amicroorganisms’ ability to reverse the DNA damage caused by UV-disinfection in the presence ofvisible light. Therefore, the authors of this master’s thesis pose the following research question:To what extent does photoreactivation and particle content affect the UV-irradiation of treatedwastewater, and what measures can be taken to reduce the effects of these two factors?
To investigate the research question, the authors perform laboratory tests on samples of wastewaterfrom a local wastewater treatment plant. The laboratory tests are designed to compare the degree ofinactivation of bacteria in treated wastewater to wastewater affected by an increase of particles andthe presence of visible light.
The authors conclude that photoreactivation affects UV-irradiation to a small extent, and that theeffect of photoreactivation can be reduced by adapting measures that ensure no visible light reachesthe inactivated bacteria. As opposed to photoreactivation, the particle content affects UV-irradiationto a significant extent. To reduce the effect of particles on UV-irradiation of bacteria, filtration can beused as a final treatment measure before UV-irradiation.