Browsing by Author "Birben, Nazmiye Cemre."

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    Application of photocatalysis for the treatment of grey water
    (Thesis (M.S.)-Bogazici University. Institute of Environmental Sciences, 2012., 2012.) Birben, Nazmiye Cemre.; Bekbölet, Miray.
    Defined as the all wastewater coming from urban areas except any input from toilets, grey waters constitute the largest fraction of the total domestic wastewater consumption which may fluctuate in quality and quantity diversely. Since grey water is less contaminated by nutrients, inorganics and hazardous organic substances, it is a potential ‘’non-conventional’’ water resource. As a consequence, several treatment technologies to treat and reuse grey water have been studied widely. As one of these processes, photocatalytic oxidation, which relies upon the generation of highly reactive hydroxyl radicals under UV radiation, has become an innovative and effective technology for the treatment of grey water in terms of degradation of refractory organic matter and potential disinfection mechanism. This study aimed to investigate applicability of photocatalytic oxidation process to treat grey water sources. In this manner, synthetically prepared grey water samples were subjected to photocatalytic oxidation in the presence of TiO2 as the semiconductor photocatalyst. Further assessment of the system performance was observed by making compositional alterations of grey water samples in terms of organic matter loading, anion concentration, and microbiological content particularly. The results of photocatalytic oxidation experiments were deliberated by the determination of selected specified and specific UV-vis and fluorescence parameters. In addition to specified UV-vis parameters, DOC and bacterial content of samples were also evaluated in terms of removal efficiencies and photocatalytic degradation kinetics expressed by pseudo- first order kinetic modeling. As a consequence, photocatalytic oxidation of low load grey water with microorganism and low anion content revealed the most effective results in terms of the removal of selected parameters whereas lowest removal efficiencies for the selected parameters were achieved by photocatalytic oxidation of high load grey water with high anion content indicating the impact of organic matter loading and anion strength on the performance of photocatalytic oxidation process.
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    Removal of organics in reverse osmosis concentrate by advanced treatment
    (Thesis (Ph.D.) - Bogazici University. Institute of Environmental Sciences, 2020., 2020.) Birben, Nazmiye Cemre.; Bekbölet, Miray.
    Due to its effective and reliable purification performance, reverse osmosis technology is one of the practical and affordable ways to produce high quality recycled water. However, a major drawback of reverse osmosis is the production of concentrate usually accounting for 15-20% of the input stream containing high levels of organic pollutants some of which could be toxic and bio-accumulative. Possessing a threat to the environment, reverse osmosis concentrate (ROC) must be treated to reduce or even eliminate the negative impact associated with the presence of organic pollutants. The main objective of this research was to investigate the applicability of homogeneous and heterogeneous advanced oxidation processes on municipal wastewater derived reverse osmosis concentrate treatment. For this purpose, reverse osmosis concentrate samples in the absence and presence of emerging contaminants were synthetically prepared with respect to physicochemical characteristics reported in the literature. Sulfamethoxazole and Carbamazepine were selected as target emerging contaminants owing to their common presence in wastewater sources. UVC/H2O2 and Fenton processes were selected as homogeneous advanced oxidation processes whereas solar photocatalysis by using commercially available photocatalysts as well as synthesized ones was considered as heterogeneous advanced oxidation process. Assessment of selected processes for their effectiveness on the removal of complex organic matter was presented in comparison to the sole photolytic oxidation conditions. Since molecular size distribution profiles of organic compounds in ROC plays an important role in order to assess the removal of different pollutants with respect to different molecular size fractions ROC samples were exposed to molecular size fractionation prior to and following photolytic and photocatalytic degradation processes. Expected potential risk was investigated through toxicity assessment prior to and following photodegradation and photocatalytic degradation processes. Organic fraction of reverse osmosis concentrate samples were monitored mainly by UV-vis and advanced fluorescence spectroscopic techniques in combination with PARAFAC modeling as well as organic carbon content.