Photochemical, UV and Ozone Based Advanced Oxidation Processes for Treatment of Aqueous Contaminants
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2018-04-27
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Abstract
In this research, advanced oxidation processes for the degradation of certain aqueous contaminants in municipal and industrial wastewater were studied. Carbamazepine (CBZ) was selected as it is an emerging contaminant in municipal wastewater. Sulfolane and acid extractable organics (AEOs) of oil sands process water (OSPW) were selected as candidates for industrial wastewater. The studies were conducted using a variety of advanced oxidation processes including a sunlight mediated photochemical process using ferric ions. Degradation kinetics of different oxidation processes in spiked water and post-secondary treated wastewater/sulfolane contaminated groundwater/OSPW were investigated. Batch experiments as well as flow through photo-reactor experiments were conducted. Degradation of CBZ in spiked water and post-secondary treated wastewater was studied using UVC, UVA, UVC/H2O2, UVA/H2O2, UVC/TiO2, UVA/TiO2, O3, UVC/O3 and UVA/O3 in a batch photo-reactor. The optimum parameters of each process were identified and their impacts on degradation rates were investigated. Relationship between UV intensity and CBZ degradation rate was extrapolated to the performance of the UV disinfection unit of a local wastewater treatment plant in Calgary, Canada. Addition of 100 mg/L of H2O2 to the secondary treated wastewater effluent entering UV disinfection unit could achieve over 60% degradation of CBZ. The effective parameters of UVC/H2O2 process in the batch experiments were further advanced to a flow through photo-reactor for degradation of CBZ. The kinetics of degradation in the flow-through reactor were in good agreement with the relationships developed using batch photo-reactor in spiked water and post-secondary treated wastewater. Experiments on ozone and photo-assisted ozone for the treatment of CBZ have shown that photo-assisted ozonation leads to greater mineralization of CBZ in water/wastewater matrices. This study recommends that UV and ozone doses for photo-assisted ozonation applications should also consider organic constituents of water matrices along with target contaminants of interest. Finally, the feasibility of a sunlight mediated photochemical process using ferric ions for the treatment of a wide range of organic contaminants was studied. Batch experiments were conducted under natural sunlight to study the degradation of CBZ, sulfolane and AEOs of OSPW. Complete CBZ degradation and more than 60% reduction of AEOs were obtained using this process. The presence of organic matter decreased the kinetics of sulfolane degradation where 30% degradation in spiked contaminated groundwater was noted. The unique ability to degrade a wide range of contaminants from this process using only natural solar irradiation, suggest a higher application potential in wastewater treatment.
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Somathilake, M. K. P. T. (2018). Photochemical, UV and Ozone Based Advanced Oxidation Processes for Treatment of Aqueous Contaminants (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/31857