Ozonation is currently considered as one of the most effective microbial disinfection technologies due to its powerful disinfection capacity and reduction in levels of chlorinated disinfection by-products (DBP). However, ozonation of waters containing bromide can produce bromate ion above regulated levels, leading to tradeoffs between microbial and chemical risks. In efforts to meet increasingly stringent drinking water regulations and to be cost-effective, water suppliers are required to optimize ozone dosage. Therefore, there is a need to develop a robust and flexible tool to accurately describe ozone disinfection processes and contribute to their design and operation. Computational fluid dynamics (CFD) has come into use recently for evaluating disinfection systems. However, the focus of its application has been largely on modelling the hydraulic behaviour of contactors, which is only one component of system design. The significance of this dissertation is that a fully comprehensive three dimensional (3D) multiphase CFD model has been developed to address all the major components of ozone disinfection processes: contactor hydraulics, ozone mass transfer, ozone decay, and microbial inactivation. The model was validated using full-scale experimental data, including tracer test results and ozone profiles from full-scale ozone contactors in two Canadian drinking water treatment plants (WTPs): the DesBaillets WTP in Montréal, Quebec and the Mannheim WTP in Kitchener, Ontario. Good agreement was observed between the numerical simulation and experimental data. The CFD model was applied to investigate ozone contactor performance at the DesBaillets WTP. The CFD-predicted flow fields showed that recirculation zones and short circuiting existed in the DesBaillets contactors. The simulation results suggested that additional baffles could be installed to increase the residence time and improve disinfection efficiency. The CFD model was also used to simulate ozone contactor performance at the Mannheim Water Treatment Plant before and after installing new liquid oxygen (LOX) ozone generators and removing some diffusers from the system. The modelling results indicated that such changes led to an increase in effective residence time, and therefore an adjustment to operational parameters was required after system modification. Another significant contribution is that, for the first time, the Eulerian and Lagrangian (or particle tracking) approaches, two commonly utilized methods for predicting microbial inactivation efficiency have been compared for the study of ozone disinfection processes. The modelling results of two hypothetical ozone reactors and a full scale contactor suggested that the effective CT values predicted by the Lagriangian approach were slightly lower than those obtained from the Eulerian approach but their differences were within 10%. Therefore, both approaches can be used to predict ozone disinfection efficiency. For the full scale contactor investigated, the tracer residence time distribution predicted by the Euerlian approach provided a better fit to the experimental results, which indicated that the Eulerian approach might be more suitable for the simulation of chemical tracer performance. The results of this part of work provided important insight in understanding the complex performance of multiphase ozonation systems and played an important role in further improving CFD modelling approaches for full-scale ozone disinfection systems. The third significant contribution of this work is that a CFD model was applied to illustrate the importance of ozone residual monitoring locations and suggest an improved strategy for ozone residual monitoring. For the DesBaillets ozone contactors, the CFD modelling results showed that ozone residuals in the cross section of the outlets of some contactor chambers differed by an order of magnitude. The “optimal” area of monitoring locations however varied at different operational conditions. Therefore, it was suggested that multiple ozone residual sampling points should be installed based on CFD analysis and experimental studies, to provide more accurate indicators to system operators. The CFD model was also used to study the factors affecting the residence time distribution (RTD). The results suggested that the selection of the tracer injection locations as well as tracer sampling locations might affect the RTD prediction or measurement. The CFD-predicted T10 values at different outlet locations varied by more than 10% variation. It is therefore recommended that CFD modelling be used to determine tracer test strategy before conducting a full-scale tracer test, and multiple sampling points should be employed during tracer tests, if possible. In addition, a research based on full-scale investigation has also been done to compare the three different CT prediction approaches: CT10, integrated disinfection design framework (IDDF), and CFD, to determine the most appropriate method for design and operation of ozone systems. The CFD approach yielded more accurate predictions of inactivation efficacy than the other two approaches. The current results also suggested that the differences in the three approaches in CT predictions became smaller at higher contactor T10/T ratios conditions as the contactors performed more closely to ideal plug flow reactors. This study has demonstrated that the computational fluid dynamics (CFD) approach is an efficient tool for improving ozone disinfection performance of existing water treatment plants and designing new ozonation systems. The model developed in this study can be used for ozone contactor design, evaluation, and troubleshooting. It can also be used as a virtual experimental tool to optimize ozone contactor behaviour under varying water quality and operational conditions.

Ozonation is currently considered as one of the most effective microbial disinfection technologies due to its powerful disinfection capacity and reduction in levels of chlorinated disinfection by-products (DBP). However, ozonation of waters containing bromide can produce bromate ion above regulated levels, leading to tradeoffs between microbial and chemical risks. In efforts to meet increasingly stringent drinking water regulations and to be cost-effective, water suppliers are required to optimize ozone dosage. Therefore, there is a need to develop a robust and flexible tool to accurately describe ozone disinfection processes and contribute to their design and operation. Computational fluid dynamics (CFD) has come into use recently for evaluating disinfection systems. However, the focus of its application has been largely on modelling the hydraulic behaviour of contactors, which is only one component of system design. The significance of this dissertation is that a fully comprehensive three dimensional (3D) multiphase CFD model has been developed to address all the major components of ozone disinfection processes: contactor hydraulics, ozone mass transfer, ozone decay, and microbial inactivation. The model was validated using full-scale experimental data, including tracer test results and ozone profiles from full-scale ozone contactors in two Canadian drinking water treatment plants (WTPs): the DesBaillets WTP in Montréal, Quebec and the Mannheim WTP in Kitchener, Ontario. Good agreement was observed between the numerical simulation and experimental data. The CFD model was applied to investigate ozone contactor performance at the DesBaillets WTP. The CFD-predicted flow fields showed that recirculation zones and short circuiting existed in the DesBaillets contactors. The simulation results suggested that additional baffles could be installed to increase the residence time and improve disinfection efficiency. The CFD model was also used to simulate ozone contactor performance at the Mannheim Water Treatment Plant before and after installing new liquid oxygen (LOX) ozone generators and removing some diffusers from the system. The modelling results indicated that such changes led to an increase in effective residence time, and therefore an adjustment to operational parameters was required after system modification. Another significant contribution is that, for the first time, the Eulerian and Lagrangian (or particle tracking) approaches, two commonly utilized methods for predicting microbial inactivation efficiency have been compared for the study of ozone disinfection processes. The modelling results of two hypothetical ozone reactors and a full scale contactor suggested that the effective CT values predicted by the Lagriangian approach were slightly lower than those obtained from the Eulerian approach but their differences were within 10%. Therefore, both approaches can be used to predict ozone disinfection efficiency. For the full scale contactor investigated, the tracer residence time distribution predicted by the Euerlian approach provided a better fit to the experimental results, which indicated that the Eulerian approach might be more suitable for the simulation of chemical tracer performance. The results of this part of work provided important insight in understanding the complex performance of multiphase ozonation systems and played an important role in further improving CFD modelling approaches for full-scale ozone disinfection systems. The third significant contribution of this work is that a CFD model was applied to illustrate the importance of ozone residual monitoring locations and suggest an improved strategy for ozone residual monitoring. For the DesBaillets ozone contactors, the CFD modelling results showed that ozone residuals in the cross section of the outlets of some contactor chambers differed by an order of magnitude. The “optimal” area of monitoring locations however varied at different operational conditions. Therefore, it was suggested that multiple ozone residual sampling points should be installed based on CFD analysis and experimental studies, to provide more accurate indicators to system operators. The CFD model was also used to study the factors affecting the residence time distribution (RTD). The results suggested that the selection of the tracer injection locations as well as tracer sampling locations might affect the RTD prediction or measurement. The CFD-predicted T10 values at different outlet locations varied by more than 10% variation. It is therefore recommended that CFD modelling be used to determine tracer test strategy before conducting a full-scale tracer test, and multiple sampling points should be employed during tracer tests, if possible. In addition, a research based on full-scale investigation has also been done to compare the three different CT prediction approaches: CT10, integrated disinfection design framework (IDDF), and CFD, to determine the most appropriate method for design and operation of ozone systems. The CFD approach yielded more accurate predictions of inactivation efficacy than the other two approaches. The current results also suggested that the differences in the three approaches in CT predictions became smaller at higher contactor T10/T ratios conditions as the contactors performed more closely to ideal plug flow reactors. This study has demonstrated that the computational fluid dynamics (CFD) approach is an efficient tool for improving ozone disinfection performance of existing water treatment plants and designing new ozonation systems. The model developed in this study can be used for ozone contactor design, evaluation, and troubleshooting. It can also be used as a virtual experimental tool to optimize ozone contactor behaviour under varying water quality and operational conditions.

Organic solvents in varnish can easily cause volatile organic compounds (VOCs) and odorous problems in manufacturing plants of enamel insulated wire. In general, the related process exhaust gases are treated by catalytic incinerators. However, the slight odors in the incinerated exhausts may induce uncomfortable feels to the inhabitants in the vicinity of the plants. Main components of odors are reported to be xylenes and to a lesser extent ketones. This study intended to oxidize the odorous compounds by chemical scrubbing method with either sodium hypochlorite or ozone as an oxidant and hydrogen peroxide as a reducing agent for the elimination of residual chlorine or ozone emitted from the oxidation scrubber. An additional study was the oxidation of aqueous mixed xylenes by sodium hypochlorite. The first part of the study was the chemical oxidation of aqueous xylenes by sodium hypochlorite. Results indicated that more than 95 % of 20 mg/L xylenes could be converted to some oxygenated hydrocarbons with an initial effective chlorine concentration of 180 mg/L at pH 6.5 over a prolonged reaction time of over 120 min. With pH < 3 and a reaction time of 120 min, xylenes could be oxidized to benzene carboxylic acid that precipitated as organic crystalline solids to the reactor bottom. The second part was chemical scrubbing of the odorous gases emitted from the catalytic incinerator. Operation conditions were an effective chlorine concentration of 1,500 mg/L and pH 6.5 for the oxidative scrubbing liquor, and a hydrogen peroxide concentration of 700 mg/L and pH > 12 for the reductive one. Results indicated that on an average, around 59 % of the influent xylenes could be removed, and the scrubbed gas was nearly odorless. 65.0 - 98.5 % of the influent non-aromatic compounds could be removed with trace amounts of chlorinated compounds in the gas were detected. The third one was the treatment of the odorous gases by using ozone as an oxidant and followed by activated carbon adsorption. 18 - 34 mg/m3 of ozone was added to the test gas with initial xylene concentrations of 25 - 55 mg/m3. Results indicated that only around 35 % of the added xylene was removed with ozone contact times of 0.15 - 0.6 min. Although 99.9 % of the residual ozone and odors were removed by the activated carbon, a longer operation time should be tested to verify the performance. Trace amounts of ring cleavage precursors of 2.4-dimethylphenol and ring cleavage products were found in the ozonized gas.

The presence of pharmacologically active and persistent compounds in drinking water sources is an environmental and public health concern. Sources of pharmaceuticals in the aquatic environment include wastewater treatment plant effluents and veterinary use. Antibiotics are of special concern because of their role in the spread of bacterial resistance. Conventional drinking water treatment processes are often ineffective for removing trace organic contaminants. Ozonation processes have demonstrated the ability to remove pharmaceutical compounds from drinking water supplies. During the ozonation of drinking water, the primary oxidants are ozone and hydroxyl radicals formed during the decomposition of ozone. Both oxidants contribute to the removal of pharmaceutical compounds; however, the relative rates of destruction by these two oxidants depends on the treatment operating conditions, the background water chemistry and the structure and reactivity of the target compound. This study investigated the relative impact of natural water characteristics, such as pH, the carbonate system, and natural organic matter, on the removal of the fluoroquinolone antibiotic ciprofloxacin by ozonation processes. Rate constants for k"O3, Cip obtained at pH 7 were approximately one order of magnitude higher than at pH 5 because ciprofloxacin changes from a positively charged cation to a neutral species over this pH range. The results showed that there was very little variation of the rate constants for ciprofloxacin oxidation by O₃ or hydroxyl radicals regardless of the carbonate concentration or the presence of the two organic matters studied in this research. Typical values for k"O3, Cip and k"HO°, Cip obtained at pH 7 ranged between 1.49x10⁴ and 1.64x10⁴ M⁻¹s⁻¹ and 1.29x10¹⁰ to 1.80x10¹⁰ M⁻¹s⁻¹, respectively. However, the presence of carbonate and other hydroxyl radical scavengers did have an impact on O₃ and hydroxyl radical exposure. The relative impact of these two oxidants changed depending on the pH of the system and the presence of carbonate and natural organic matter. / text

The ubiquitous presence and chronic effect of pharmaceuticals is one of the emerging issues in environmental field. As a result of incomplete removal by sewage treatment plants, pharmaceuticals are released into the environment and drinking water sources. On the other hand, conventional drinking water treatment processes such as coagulation, filtration and sedimentation are reported to be ineffective at removing pharmaceuticals. Therefore, the potential presence of pharmaceuticals in finished drinking water poses a threat on public health. Antibiotics, as an important group of pharmaceuticals, are given special concerns because the potential development of bacteria-resistance. Ozonation and advanced oxidation processes are demonstrated to be quite effective at removing pharmaceuticals. The oxidation of pharmaceuticals is caused by ozone itself and hydroxyl radicals that are generated from ozone decomposition. Whether ozone or hydroxyl radicals are the primary oxidant depends on the specific pharmaceutical of interest and the background water matrix. In this research, erythromycin, a macrolide antibiotic, was chosen as the target compound because of its high detection frequency in the environment and its regulation status. The objective of this research was to investigate the removal performance of erythromycin by ozonation from the standpoint of kinetics. The effects of pH, carbonate and phosphate buffers, and initial ozone dose on ozonation of erythromycin were also studied. The second-order rate constant for the reaction between deprotonated erythromycin and ozone was determined to be 4.44x10⁹ M⁻¹·s⁻¹ while protonated erythromycin did not react with ozone. Ozone was determined to be the primary oxidant for erythromycin removal by ozonation. pH was found to have great positive impact on the degradation of erythromycin by ozonation due to the deprotonation of erythromycin at high pH. Carbonate and phosphate buffers were found to have negligible effects on the degradation of erythromycin by ozonation. Initial ozone dose showed a positive impact on the total erythromycin removal rate by ozonation. / text

Orientador: Maria Valnice Boldrin Zanoni / Coorientador: Guilherme Garcia Bessegato / Banca: Maria Angelica Martins Costa / Banca: Luis Augusto Martins Ruotolo / Resumo: O uso de protetores solares para abrandar os efeitos danosos da radiação solar à pele humana leva à contaminação da água de piscinas, o que pode ser prejudicial à saúde humana e ao ambiente. O presente trabalho investiga uma alternativa para o tratamento de piscinas usando a fotoeletrocatálise combinada à ozonização (FEC+O3). A técnica baseia-se na geração de radicais hidroxila (•OH) que podem mineralizar os compostos orgânicos a CO¬2 e H¬¬2O. Neste trabalho, a 3-benzofenona, substância amplamente utilizada em protetores solares comerciais, foi usada como composto modelo para investigação da eficiência de tratamento por FEC+O3. Monitorou-se também a degradação de ureia e a desinfecção da água usando o fungo Candida parapsilosis. Inicialmente, foram desenvolvidos reatores fotoeletrocatalíticos anulares de bolhas, onde os corantes Amarelo Ácido 1 e Azul de Metileno fora utilizados como modelos de poluentes coloridos. A melhor configuração do reator foi aquela utilizando fotoânodo de nanotubos de TiO2, contra eletrodo de DSA com grande área geométrica, lâmpada UV-B de 36 W, borbulhador de vidro sinterizado e aplicação de 2,0 V no sistema fotoeletrocatalítico. A utilização deste reator promoveu a remoção de 100 % de 3-benzofenona após 20 min de tratamento de solução contendo 30,0 mg L−1 em 0,01 mol L−1 de sulfato de sódio sob irradiação UVB de 36 W, voltagem de 2,0 V e vazão de 3,85 × 10−4 mol min−1 ¬de O¬3. Os resultados indicam que a remoção de carbono orgânico total atinge 90%... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The sunscreen used to minimise the harmful effects from solar radiation to the human skin leads to swimming pool water contamination, which can be harmful to human health and to the environment. The present work investigates an alternative for swimming pool treatment using photoelectrocatalysis coupled with ozonation. The technique is based on hydroxil radical generation (•OH) that can mineralize organic compounds to CO2 and H2O. Assays were done in this work with fortified water with benzophenone-3 used as model compound of sunscreens widely used in commercial sun blockers. The method yet monitored the urea degradation and the water disinfection using the fungus Candida parapsilosis. Firstly, photoelectrocatalytic reactors coupled with ozonation process were developed and for this, Yellow Acid 1 and Methylene Blue dye were used as colorful pollutant models. The best reactor configuration was the one using TiO2 nanotubes as photoanode in tube format with holes, auxiliary electrode made of DSA® with high geometric area, 36 W UVB emission lamp, sintered glass bubbler and 2,0 V applied voltage in the photoelectrocatalytic system. The reactor usage shows 100% removal of 3-benzophenone after 20 min treatment of solution containing 30.0 mg L−1 in 0.01 mol L−1 of sodium sulfate under UVB radiation, 2,0 V applied voltage and 3.85x10-4 mol min−1 O3 flow rate. The results indicate the removal of total organic carbon reach 90% after 120 minutes treatment. Likewise, the technique reached... (Complete abstract click electronic access below) / Mestre

Espécies de microalgas como Chlorella sorokiniana têm sido investigadas para as mais variadas aplicações como biocombustíveis, nutrição e a recuperação de nutrientes. Entretanto, a separação de microalgas do meio líquido permanece um desafio tanto técnico quanto econômico. O objetivo deste trabalho é propor e investigar a utilização de pré-ozonização e flotação por ar dissolvido para a separação sólido-líquido de Chlorella sorokiniana cultivada em meio padrão M8a em fotobiorreator flat panel, utilizando polímero catiônico à base de poliacrilamida como coagulante. Primeiramente, foi avaliado o sistema de tratamento com flotação por ar dissolvido, que foi otimizada em escala de laboratório visando eficiência de remoção de algas e flexibilização do sistema. Utilizando dosagens de polímero catiônico de 10 mg L-1 obteve-se remoções de cor aparente, turbidez e densidade óptica próximas de 95 &#37; em pH 7. Posteriormente, a etapa de mistura lenta foi retirada do sistema, a razão de recirculação foi diminuída de 10 para 4 &#37; e após essas alterações, obteve-se remoção de microalgas acima de 90 &#37; para dosagem de polímero de 10 mg L-1. Para analisar o efeito da pré-ozonização a dosagem de polímero catiônico foi reduzida para 7 mg L-1, e observou-se que com FAD esta dosagem removeu 81,12 &#37; de turbidez, e após pré-ozonização por 5 minutos seguida de FAD a eficiência de remoção de turbidez chegou a 91,78 &#37; e remoção de cor aparente aumentou 6,25 &#37;. A utilização da pré-ozonização permitiu utilização de velocidades de flotação da ordem de 24 cm min-1 sem prejuízo da eficiência de remoção de cor, turbidez e densidade óptica. Observou-se que a pré-ozonização demonstra efeitos positivos no sistema de tratamento, mas constatou-se uma dosagem ótima de ozônio, e que a partir desta dosagem a eficiência do tratamento pode ser prejudicada. Foi constatado que uma possível explicação para esse fato seja a liberação de matéria orgânica algal após pré-ozonização, em dosagens acima do valor ótimo de dosagem de ozônio. / Microalgal species as Chlorella sorokiniana have been investigated for a variety of applications such as biofuels, nutrition and nutrient recovery. However, the solid-liquid separation microalgae of the liquid medium remains a challenge both technical as economical. This work aims to propose and investigate the use of preozonation and dissolved air flotation for solid liquid separation of Chlorella sorokiniana cultivated in standard M8a medium in a flat panel photobioreator, using cationic polyacrylamide based polymer as coagulant. Initially, treatment system including dissolved air flotation was evaluated, which was optimezed at laboratory scale targeting removal efficiency of microalgae and system flexibility. Using cationic polymer dosage of 10 mg L-1, were obtained apparent color, turbidity and optical density removals nearly to 95&#37; in pH 7. Further, the step of slow mixing was removed from the system, the recycle ratio was decreased from 10 to 4&#37; and after these changes, was obtained microalgae removal over 90&#37; at polymer dosage of 10 mg L-1. To analyse the effect of preozonation, cationic polymer dosage was decreased to 7 mg L-1, and was observed 81.12 &#37; turbidity removal with this polymer dosage at FAD, and after 5 minutes preozonation followed by FAD, turbidity removal efficiency reached 91.8 &#37; and apparent color removal increased 6.25 &#37;. The utilization of preozonation allowed use of flotation velocities in the order of 24 cm min-1 without damaging variables removal efficiency. It was observed tha preozonation shows positive effects in treatment system, but was found an optimum ozone dosage from which the treatment efficiency is hampered. It was observed that a possible explanation to this fact is the release of algogenic organic matter after preozonation in dosages over the optimum value of ozone dosage.

Orientador: Marco Aurélio Cremasco / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-21T17:25:48Z (GMT). No. of bitstreams: 1 VergelZapata_CarlosFernando_M.pdf: 3787074 bytes, checksum: c52cfd4ba974066436ff88b0a07c8b76 (MD5) Previous issue date: 2012 / Resumo: Os modelos matemáticos são utilizados como instrumentos de suporte operacional para melhorar e facilitar a otimização de um processo. No presente trabalho foi proposto um modelo simplificado para determinar a concentração de ozônio na água destilada por meio de um processo de ozonização em uma coluna de borbulhamento, em condições isotérmicas (21°C) e isobáricas (pressão atmosférica). O modelo foi baseado em uma cinética de reação de segunda ordem para a decomposição de ozônio na fase líquida. Para o desenvolvimento da modelagem a resistência do gás à transferência de massa e os efeitos da dispersão para as duas fases (gasosa-líquida) foram considerados desprezíveis. Além disso, assumiu-se composição constante de ozônio na fase gasosa. O modelo foi resolvido segundo as condições de contorno do processo, pelo método numérico Runge-Kutta de quarta ordem com a ajuda do software Matlab 7.0. Durante o processo de ozonização estudado o pH da solução não foi mantido constante, portanto no presente trabalho foi proposto uma cinética de reação de primeira ordem para a variação do pH, a qual representou satisfatoriamente. Diante dos resultados, observou-se que um aumento na concentração de ozônio na fase gasosa como condição inicial do processo e uma diminuição do pH da solução ao longo do tempo aumenta a concentração de ozônio na fase líquida. As distribuições de concentração de ozônio na água destilada obtidos da modelagem apresentaram concordância com os dados experimentais encontrados na literatura / Abstract: Mathematical models are used as operational support tools which improve and facilitate processes optimization. In this work, it was suggested a simplified model to determine the ozone concentration in distillated water, through an ozonation process in a bubble column under isothermal (21°C) and isobaric (atmospheric pressure) conditions. The model was based in second-order reaction kinetics of ozone decomposition in the liquid phase. For the modeling development, gas resistance to mass transfer and the dispersion effects for both phases (liquid-gas), were considered negligible. In addition, it was assumed a constant composition of ozone in the gaseous phase. The model was solved according the boundary conditions of the process, through the fourth-order Runge-Kutta numerical method supported on the software Matlab 7.0. During the ozonation process studied, the solutions pH wasn't maintained constant, therefore, it was proposed a first-order kinetics of reaction for the pH variation, which successfully represents. The results showed that an increase in the concentration of ozone in the gaseous phase as initial condition and a decrease of pH of solution through time increases the liquid phase ozone concentration. The ozone concentration distributions obtained of the modeling in distilled water, present agreement with the experimental data found in literature / Mestrado / Engenharia de Processos / Mestre em Engenharia Química

Master of Science / Department of Grain Science and Industry / Finlay I. MacRitchie / Ozone, a triatomic form of oxygen with a Generally Recognized As Safe (GRAS) status from the U. S. Food and Drug Administration, is a strong antimicrobial and sanitizing agent with numerous potential applications in the food industry. One of them is the improvement of wheat flour baking qualities, by replacement of the actual chlorination treatment. Following recent developments realized by the company Goemar (France) which invented and patented an ozone treatment device for wheat grain and a method for making flour from ozone-treated grains, this study aims to determine the effect of ozone treatment on wheat grain and on wheat flour, and to compare them. Three different ozone concentrations with different application times rendering three quantities of absorbed ozone have been investigated. Rheological, physicochemical and baking properties of soft wheat flours stemming from both treatments were evaluated and compared to untreated flour. Results were overall significant and showed that the treatment of flour gives more marked results than the treatment on grain for retention capacity in sucrose and volume of cakes but decreases the [alpha]-amylase activity. On the other hand, action of ozone on grain augments the maximum viscosity of the flour. Bread volume was found to be increased by both treatments in similar proportions. The treatments were also analyzed in particular and showed specific characteristics. A single treatment has not been determined to enhance all characteristics of the flour. Hence, the modification of precise features of the flour has to be related to a specific treatment.

Bioassays for baseline toxicity, which measure toxicants’ non-specific effects, have been shown in previous studies to effectively correlate with the increased presence of pharmaceuticals, personal care products, endocrine-disrupting compounds, and other synthetic organics in treated sewage effluent. This study investigated how the baseline toxicity of anthropogenic compounds-spiked wastewater changed during the treatment of biofiltration and ozone oxidation, as measured by the bioluminescence inhibition of the Vibrio fischeri bacterium. The water quality parameters of dissolved organic carbon, seven common anions, and fluorescence spectroscopy were used to corroborate and collate with the toxicity results. Water quality was evaluated on two bench-scale soil filtration columns, which were configured for pre-ozonation and post-ozonation. Both systems’ soil aerobically removed similar amounts of dissolved organic carbon, and the reduction ranged between 57.7% and 62.1% for the post-ozonation and pre-ozonation systems, respectively. Biological removal of DOC, protein-like, humic-like, and soluble microbial product-like material was highest in the first 28.5 cm of each 114 cm-long system. While bioluminescence inhibition showed that ozonation was effective at lowering baseline toxicity, this study’s bioassay procedure was a very poor indicator of soil filtration treatment; both system’s effluents were significantly more toxic than their non-ozonated influents.