O presente trabalho considera o problema de oxidação de matéria orgânica e inorgânica em esgoto sanitário através da ozonização, buscando aprofundar o conhecimento nos aspectos dúbios levantados em pesquisas conduzidas no Departamento de Hidráulica e Saneamento da EESC (Escola de Engenharia de São Carlos) na USP (Universidade de São Paulo) e também citadas na literatura da área. O projeto que tem cunho experimental utilizou uma coluna de ozonização de seção transversal quadrada de 0,19 m de lado e 2,00 m de altura, formada por duas faces paralelas de acrílico e duas faces paralelas de vidro, onde as bolhas de ozônio ascensionais eram fornecidas por um difusor microporoso instalado na base da coluna. Gerou-se um banco de dados acerca das características hidrodinâmicas das bolhas ascensionais (velocidade ascensional, porcentagem pontual da concentração, diâmetro equivalente e área interfacial específica), além de alguns parâmetros físicos e químicos (ozônio residual dissolvido e gasoso, temperatura, pH, alcalinidade, condutividade, turbidez, cor verdadeira, sulfeto, DQO, série de sólidos e série de carbono), localizados como relevantes ao processo de oxidação de matéria orgânica e inorgânica através da ozonização, variando a vazão de ozônio de 50 a 300 L/h e o nível líquido de 0,30 a 1,80 m. Constatou-se que o valor de todas as características hidrodinâmicas estudadas aumenta com o aumento da vazão de gás ozônio injetado no difusor microporoso. Vale mencionar que a velocimetria a laser não intrusiva foi a ferramenta utilizada na determinação da velocidade bi-dimensional ascensional das bolhas, além de auxiliar na determinação do diâmetro equivalente. Já a porcentagem pontual da concentração das bolhas foi determinada através da contagem de radiação de uma sonda de Césio-137. As análises dos parâmetros físicos e químicos mostraram de forma geral e repetitiva que a redução de pH e alcalinidade não foram influenciadas pela dosagem de ozônio aplicada; que a porcentagem de redução da DQO teve um comportamento oscilatório, ora influenciado ora não influenciado pela dosagem de ozônio aplicada; que a condutividade teve redução nula; e que a turbidez e a cor verdadeira tiveram influência da dosagem de ozônio na eficiência de redução. A observação dos experimentos permitiu inferir que tanto as características físicas como as características de qualidade do efluente influem no tipo de comportamento observado para a DQO em função do tempo de contato. Os comportamentos previstos pela solução de equações básicas geradas para explicar o efeito inibidor de compostos intermediários permitiram obter evoluções monotonicamente crescentes ou monotonicamente decrescentes no tempo, além dos comportamentos oscilatórios da eficiência de redução da DQO observados neste trabalho. Os resultados experimentais das velocidades ascensionais, perfis da concentração das bolhas, diâmetros equivalente e áreas interfaciais específicas, em conjunto com os parâmetros físico-químicos (ozônio residual dissolvido e gasoso, temperatura, pH, alcalinidade, condutividade, turbidez, cor verdadeira, sulfeto, DQO, série de sólidos e série de carbono), formam um banco de dados a ser utilizado nas simulações da coluna de ozonização que virão a decorrer do presente trabalho. As equações governantes aqui apresentadas são merecedoras de estudos posteriores para o entendimento da dinâmica existente nas colunas de ozonização e a busca da otimização de seu uso. / This present work is a study about the oxidation problem of organic and inorganic matter in sanitary effluent by means of the ozonation, trying to improve the knowledge of dubious aspects considered in prior researches conducted in Department of Hydraulic and Sanitation of the EESC (Escola de Engenharia de São Carlos) at USP (Universidade de São Paulo) and also found in specific studies. The project, which has experimental objective, used a column of ozonation of square transversal section of 0.19 m of side and 2.00 m of height with two parallel faces of acrylic and two parallel faces of glass, where bubbles of ozone in ascension were provided by a microporous diffuser installed in the base of the column. A file of data about hydrodynamic characteristics of the bubbles in ascension (velocity in ascension, punctual percentage of the concentration, equivalent diameter and specific interface area) was stored, besides some physical and chemical parameters (waste ozone dissolved and gaseous, temperature, pH, alkalinity, conductivity, turbidity, real color, sulphet, COD, set of solids and set of carbon), important to the process of inorganic and organic matter oxidation by means of ozonation, changing the flow of the ozone from 50 to 300 L/h and the liquid level from 0.30 to 1.80 m. It was noticed that the value of all hydrodynamic characteristics analysed increases when the flow of the ozone injected in the microporous diffuser also increases. It is important to mention that no-indisposition laser velocimetry was used as an instrument to determine the bi-dimension velocity of the bubbles in ascension and to help determine the equivalent diameter, whereas the punctual percentage of the concentration of the bubbles was determined by means of counting Cesium-137 radiation. Analysis of chemical and physical parameters showed in a general and repetitive way that the reduction of the pH and alkalinity was not influenced by the dose of ozone used; the percentage of COD reduction had oscillated behaviour, being or not influenced by the dose of the ozone used. It also showed that conductivity had zero reduction and turbidity and real color here influenced by the dose of the ozone in terms of efficient reduction. The observation of the experiments permitted to infer that both physical and quality characteristics of the effluent influence the type of the behaviour of COD versus contact time. The behaviour expected by the solution of basic equations done to explain the inhibiting effect of intermediate compounds permitted to obtain increasing and decreasing evolutions in time, as well oscillated behaviour of the efficiency of COD reduction observed in this work. The experimental results of the velocities in ascension, the profile of the bubble concentration, equivalent diameter and specific interface area with chemical and physical parameters (waste ozone dissolved and gaseous, temperature, pH, alkalinity, conductivity, turbidity, real color, sulphet, COD, set of solids and set of carbon) organize a file of data to be used in simulations of the ozonation column which will elapse from this present work. Specific equations here presented are worthy of further studies for the understanding of the dynamic present in the ozonation columns and the search of the optimization of its application.

O presente trabalho foi realizado em sua maior parte no Brasil. Entretanto, com o intuito de enriquecer a pesquisa, realizou-se coleta de dados por um período de seis meses na Universidade de Wageningen - Holanda. Na etapa realizada no Brasil se propôs: estudar a formação de subprodutos (aldeídos e trialometanos) da desinfecção de efluente de tratamento anaeróbio esgoto sanitário com ozônio, cloro e ozônio/cloro; verificar como os desinfetantes atuam no processo de oxidação; conhecer o grau de toxicidade bem como o efeito do residual do ozônio e cloro empregando Daphnia similis e Danio rerio como organismos-teste e, ainda, analisar a eficiência do ozônio, cloro, ozônio/cloro na inativação de microrganismos. Na etapa da pesquisa realizada na Holanda se propôs: estudar a formação de subprodutos (aldeídos) da desinfecção de efluente de tratamento anóxico com ozônio, ozônio/cloro e ozônio/peróxido de hidrogênio (peroxônio); verificar como os desinfetantes atuam no processo de oxidação; e, ainda, analisar a eficiência do ozônio, ozônio/cloro na inativação de microrganismos indicadores. Nos estudos realizados, pode-se verificar uma expressiva formação de aldeídos com predominância de formaldeído e, principalmente, acetaldeído que apresentou uma maior concentração de formação para os ensaios realizados no Brasil. A formação de aldeídos nos ensaios realizados na Holanda seguiram o mesmo comportamento dos realizados no Brasil, porém, como uma menor formação. Para os ensaios de cloração e ozonização/cloração foi observada a baixa formação de trialometanos. Os testes de toxicidade que usaram como organismo-teste - Daphnia similis - apresentaram toxicidade nos ensaios em que se aplicou 8,0 mg \'O IND.3\'/L, assim como em todas dosagens aplicadas nos ensaios de cloração e, também, para o ensaio de ozonização/cloração para dosagem aplicada de 5,0 mg \'O IND.3\'/L / 10 mg \'CL IND.2\'/L. Em relação ao organismo-teste - Danio rerio - foi detectado toxicidade aguda no ensaio em que se aplicou 5,0 mg \'O IND.3\'/L e tempo de contato 5 minutos e 8,0 mg \'O IND.3\'/L e tempo de contato 15 minutos. / The present work was mostly carried out in Brazil. However, aiming to enhance the research, a six-month data collection was performed at the Wageningen University - the Netherlands. The step carried out in Brazil proposed: to study the formation of by-products (aldehydes and trihalomethanes) from the disinfection of an anaerobic treatment wastewater effluent with ozone, chlorine and ozone/chlorine; to verify how disinfectants act in the oxidation process; to know the degree of toxicity as well as the effects of residual ozone and chlorine employing Daphnia similis and Danio rerio as test-organisms; and, yet, to analyze the efficiency of ozone, chlorine and ozone/chlorine in the inactivation of microorganisms. The step of this research that was carried out in the Netherlands proposed: to study the formation of by-products (aldehydes) from the disinfection of an anoxic treatment effluent with ozone, ozone/chlorine and ozone/hydrogen peroxide (peroxonium); to verify how disinfectants act in the oxidation process; and, to analyze the efficiency of ozone, ozone/chlorine in the inactivation of indicating microorganisms. It was possible to indentify, in the performed studies, an expressive formation of aldehydes with a formaldehyde predominance and, mainly, acetaldehyde that presented a higher formation concentration in the essays carried out in Brazil. The aldehydes formation concentration detected in the essays carried out in The Netherlands followed the same behavior of the ones carried out in Brazil, however with a smaller formation. A low formation of trihalomethanes was observed for the chloration and ozonization/chloration, essays. The toxicity tests that used Daphnia similis as test-organisms presented toxicity in the essays that 8.0 mg \'O IND.3\'/L was applied, as well as for all applied dosages in the chloration essays and, also, for the ozonation/chloration for the applied dosage of 5.0 mg \'O IND.3\'/L / 10 mg \'CL IND.2\'/L. Regarding the Danio rerio test-organism, acute toxicity was detected in the essay in which 5.0 mg \'O IND.3\'/L and contact time of 5 minutes was applied and also for 8.0 mg \'O IND.3\'/L and contact time of 15 minutes.

The objective of this study was to evaluate the reduction on the levels of mycotoxins in wheat products and by-products: deoxynivalenol (DON) in whole wheat flour, wheat bran and the efluent from wet milling of wheat flour, and zearalenone (ZEN) in wheat bran. Firstly, the reduction of DON contamination was studied on whole wheat flour, naturaly contaminated, and considering different moisture levels, as well as in wet milling effluent of wheat flour. Further, the impact of the ozonation process on the rheological properties of the processed flour was evaluated. Secondly, the wheat bran naturally co-contaminated with DON and ZEN was studied, considering the degradation of both mycotoxins and the impact of the ozonation process on the bran phenolic compound content and on the antioxidant capacity. The DON degradation in the whole wheat flour increased with both processing time and moisture content. By changing these process parameters, it was possible to obtain products in accordance with the legal limits of Brazil and the European Union, even starting with concentration 2-4 times higher than the legal limits. However, the rheological properties of the whole wheat flour were affected by the process, probably due to protein modifications. The DON concentration on the wet milling effluent was linearly reduced by the ozonation. In wheat bran naturally contaminated and in its equilibrium moisture, the ozonation reduced both DON and ZEN contamination. The degradation of ZEN was higher and faster than the degradation of DON, which could be explained by their molecular structures. It was also observed that the ozonation process did not negatively affect the phenolic compounds and the antioxidant capacity, which is high desirable from a nutritional point of view. Consequently, this work concludes that the ozonation process was effective in reducing DON and ZEN in different wheat products and efluent. It is noteworthy that the results obtained are promising for future studies and to elucidate the mechanism of action of ozone on mycotoxins and constituents of food. / O objetivo deste estudo foi avaliar a redução nos níveis de micotoxinas em produtos e subprodutos de trigo: desoxinivalenol (DON) em farinha de trigo integral, farelo de trigo e efluente de moagem da farinha de trigo e zearalenona (ZEA) em farelo de trigo. No primeiro momento, a redução da contaminação por DON foi estudada em farinha de trigo integral, naturalmente contaminada e considerando diferentes níveis de umidade, bem como no efluente de moagem úmida da farinha. Além disso, o impacto do processo de ozonização nas propriedades reológicas da farinha processada foi avaliado. Em segundo lugar, estudou-se o farelo de trigo naturalmente co-contaminado com DON e ZEA, considerando a degradação de ambas as micotoxinas e o impacto do processo de ozonização no conteúdo do composto fenólico do farelo e na capacidade antioxidante. A degradação de DON na farinha de trigo integral aumentou tanto com o tempo de processamento quanto com o teor de umidade. Ao alterar esses parâmetros de processo, foi possível obter produtos de acordo com os limites legais do Brasil e da União Européia, mesmo com a concentração 2-4 vezes superior aos limites legais. Contudo, as propriedades reológicas da farinha de trigo integral foram afetadas pelo processo, provavelmente devido a modificações de proteínas. A concentração de DON no efluente de moagem úmida foi linearmente reduzida pela ozonização. Em farelo de trigo naturalmente contaminado e em sua umidade de equilíbrio, a ozonização reduziu a contaminação DON e ZEA. A degradação do ZEA foi maior e mais rápida que a degradação do DON, o que poderia ser explicado pelas suas estruturas moleculares. Observou-se também que o processo de ozonização não afetou negativamente os compostos fenólicos e a capacidade antioxidante, o que é altamente desejável do ponto de vista nutricional. Consequentemente, este trabalho conclui que o processo de ozonização foi efetivo na redução de DON e ZEA em diferentes produtos de trigo e efluentes. Vale ressaltar que os resultados obtidos são promissores para futuros estudos e elucidar o mecanismo de ação do ozônio sobre micotoxinas e constituintes dos alimentos.

Due to a policy of no release, oil sands process-affected water (OSPW) produced by the surface-mining oil sands industry in North Eastern Alberta, Canada, is stored on-site in tailings ponds. There is concern regarding the toxic effects of OSPW on aquatic organisms. Knowledge of the chemical composition and toxicity of OSPW is limited. Research is necessary for potential remediation and release of OSPW back into the environment. Due to the large volume and persistency of OSPW, active efforts are necessary for the remediation of OSPW before release and habitat reclamation. Currently, ozonation is considered one possible method for remediation of OSPW by reducing the concentrations of dissolved organic compounds, including naphthenic acids (NAs), which are considered among the primary toxic constituents. However, further work is needed to evaluate the effectiveness of ozonation in reducing the toxicity of OSPW and to ensure that ozonation does not increase the toxicity of OSPW. The overall objective of this work was to determine the toxic effects of OSPW on endocrine disruption and embryo development, using both in vitro and in vivo models, and the effectiveness of ozone treatment for reducing the toxicity of OSPW. In the first study, untreated and ozone-treated OSPW were examined for effects on sex steroid production using the H295R cell line steroidogenesis Assay. The results indicate that exposure to untreated OSPW can significantly decrease synthesis of testosterone (T) and increase synthesis of 17β-estradiol (E2) by 0.55±0.06 and 2.0±0.13-fold, respectively, compared to that of control groups (ρ < 0.05). These effects were due to increased aromatase enzyme activity and decreased E2 metabolism. The results also suggest that ozonation is an effective treatment to reduce concentrations of NAs in OSPW without altering steroidogenesis. In the second study, the T47D-kbluc (estrogen responsive) and MDA-kb2 (androgen responsive) cell assays were used to determine whether OSPW might act as either agonists or antagonists of the estrogen receptor (ER) or androgen receptor (AR), respectively. The estrogenic responses to untreated OSPW were significantly greater by 2.6±0.22-fold compared to control group (ρ < 0.05). Exposure to untreated OSPW produced significant antiandrogenic response in the presence of 0.01, 0.05 and 0.1 nM T by 16±6.5%, 47±7.6% and 75±9.7%, respectively, of that of the corresponding concentrations of T alone (ρ < 0.05). The results suggest that compounds in the dissolved organic fraction of OSPW have estrogenic and anti-androgenic properties, acting as ER agonists and/or AR antagonists. Ozonation of the OSPW partially mitigated the antiandrogenicity but had no effect on the estrogenicity of OSPW. In the third study, the endocrine-disrupting effects of OSPW and ozone-treated OSPW were determined by quantifying relative changes in the abundances of transcripts of genes along the brain-gonad-liver (BGL) axis in male and female fathead minnows (Pimephales promelas). The results indicate that OSPW has endocrine-disrupting effects at all levels of BGL axis and these effects of impaired expression of genes along the BGL axis are sex specific. For example, exposure to OSPW resulted in significantly greater abundances of transcripts of vtg (Vitellogenin), chg-l (Choriogenin L) and chg-h (Choriogenin H minor) by 4.9±1.2, 5.4±1.5 and 3.4±0.78-fold, respectively, compared to those of control groups (ρ < 0.05) in livers from male fathead minnow. However, in livers from female fathead minnows, exposure to OSPW resulted in significantly lesser abundances of transcripts of vtg, chg-l and chg-h by 0.002±0.0011, 0.022±0.007 and 0.036±0.024-fold, respectively, compared to those of control fish (ρ < 0.05). Ozonation of OSPW attenuated the effects on abundances of transcripts of some genes, and the attenuation was more prominent in males than in females. However, impact of ozonation on endocrine-disrupting effects of OSPW was less evident than in the in vitro studies described in Chapter 2 and 3. The results also provide a mechanistic basis for the endocrine-disrupting effects of OSPW from other studies, including impaired reproduction of fathead minnows exposed to OSPW. In the final study the effects of untreated, ozone-treated, and activated charcoal-treated OSPW (OSPW, O3-OSPW, and AC-OSPW) on the survival, growth, and development of embryos of fathead minnows were determined. Compared to the control group, which had an embryo survival rate of 98±2.1%, survival was significantly less when exposed to OSPW (44±7.1%; ρ < 0.05). Eggs exposed to untreated OSPW exhibited a significantly greater rate of premature hatching, and embryos exhibited more frequent spontaneous movements. Incidences of hemorrhage (50±3.4%), pericardial edema (56±7.1%), and malformation of the spine (38±5.4%) were significantly greater in embryos exposed to OSPW compared to control group (ρ < 0.05). Significantly greater concentrations of ROS (1.7±0.11-fold), and greater abundances of transcripts cyp3a, gst, sod, casp9, and apopen (2.4±0.34, 2.2±0.26, 3.1±0.74, 3.3±0.57 and 2.4±0.25-fold, respectively) compared to control groups (ρ < 0.05), indicated that exposure to OSPW caused oxidative stress, which can result in damage to mitochondria and promote activation of caspase enzymes and apoptotic cell death. Removal of dissolved organic constituents in OSPW by ozone treatment, or by activated charcoal, significantly attenuated all of the adverse effects associated with untreated OSPW. The results suggest that the organic fraction of OSPW can negatively impact the development of fathead minnow embryos through oxidative stress and apoptosis, and that ozonation attenuates this developmental toxicity. Overall, the findings from the research described in this thesis provide novel and important insights into the toxicity and mechanisms of the toxicity of OSPW with respect to endocrine disruption and development of embryos of fish. In addition, the research provides compelling evidence that ozonation might be an effective method for accelerating the remediation of OSPW. The results of the research might help regulators develop effective strategies for reclamation, remediation and potential release of OSPW back to the environment.

The presence of micropollutants, particularly pesticides, in surface waters across Canada has been of concern not only for their environmental impact, but also for their potential effects on human health and recalcitrant nature to conventional water treatment methods. Although ozone has been mainly applied for disinfection of drinking water, oxidation of trace organics by ozonation has been considered potentially effective. In an effort to meet increasingly stringent drinking water regulations, different solid catalysts have been used to enhance the removal of water contaminants by ozonation. In spite of the increasing number of data demonstrating the effectiveness of heterogeneous catalytic ozonation, the influence of different factors on the efficiency of micropollutants oxidation is still unclear.<p> In the present work, application of three solid catalysts in ozonation of two model micropollutants in pure water was examined using a laboratory-scale reaction system over a range of operating conditions. The three catalysts investigated were activated carbon, alumina, and perfluorooctyl alumina, and the two model micropollutants were the pesticides atrazine and 2,4-dichlorophenoxyactic acid. The effects of solution pH, presence of a radical scavenger, pesticide adsorption on catalyst, and catalyst dose on micropollutant removal were investigated. Solution pH was found to significantly influence the catalyst ability to decompose ozone into free hydroxyl radicals. The effect of these free radicals was markedly inhibited by the radical scavenger resulting in a negative impact on pesticides degradation. In general, the removal rate of pesticides was found to increase with increasing doses of catalyst.<p> In the ozonation process in the presence of activated carbon, atrazine removal rates increased four and two times when using a catalyst dose of 0.5 g L-1 at pH 3 and 7, respectively, whereas observed reaction rates for 2,4-D increased over 5 times in the presence of 1 × 10-4 M tert-butyl alcohol at pH 3. In the ozonation system catalyzed by 8 g L-1 alumina, the observed reaction rate constant of atrazine removal notably improved at neutral pH by doubling the micropollutant removal rate. For the pesticide 2,4-D in the presence of 1 × 10-4 M tert-butyl alcohol at pH 5, the observed removal rate was over ten times higher than that for the non-catalytic ozonation process using also using a catalyst dose of 8 g L-1. Modification of alumina to produce perfluorooctyl alumina resulted in a material able to significantly adsorb atrazine, while not exhibiting affinity for adsorption of 2,4-D. In spite of its adsorptive properties, perfluorooctyl alumina was found to enhance neither molecular ozone reactions nor ozone decomposition into hydroxyl radicals. Thus, the observed removal rates for atrazine and 2,4-D by ozonation in the presence of perfluorooctyl alumina did not increase significantly.

The effectiveness of partial ozonation of return activated sludge for enhancing denitrification and waste sludge minimization were examined. A pair of nitrifying sequencing batch reactors was operated in either aerobic or alternating anoxic/aerobic conditions, with one control and one ozonated reactor in each set. The amount of solids decreased with the ozone dose. Biomass in the anoxic/aerobic reactor was easier to destroy than in the aerobic one, generating approximately twice as much soluble chemical oxygen demand (COD) by cell lysis. Increased COD favoured production of extracellular polymers in ozonated reactors, enhancing flocculation and improving settling. Floc stability was also strengthened in prolonged operation in alternating treatment, resulting in declined solids destruction. Dewaterability was better in alternating reactors than in aerobic ones indicating that incorporation of an anoxic zone for biological nutrient removal leads to improvement in sludge dewatering. The negative impact of ozonation on dewaterability was minimal in terms of the long-term operation. Ozone successively destroyed indicator estrogenic compounds, contributing to total estrogen removal from wastewater. Denitrification rate improved up to 60% due to additional carbon released by ozonation. Nitrification rates deteriorated much more in the aerobic than in the alternating reactor, possibly as a result of competition created by growth of heterotrophs receiving the additional COD. Overall, ozonation provided the expected benefits and had less negative impacts on processes in the alternating treatment, although after prolonged operation, benefits could become less significant. The alternating anoxic/aerobic reactor achieved twice the nitrification rates of its aerobic counterpart. Higher removal rates of estrogens were associated with higher nitrification rates, supporting the contention that the nitrifying biomass was responsible for their removal. The alternating treatment offered the better estrogen biodegradation. Microbial populations in both reactors were examined with fluorescent in situ hybridization. Dominance of rapid nitrifiers like Nitrosomonas and Nitrobacter (79.5%) in the alternating reactor, compared to a dominance of slower nitrifiers like Nitrosospira and Nitrospira (78.2%) in the aerobic reactor were found. The findings are important to design engineers, as reactors are typically designed based on nitrifiers’ growth rate determined in strictly aerobic conditions. / October 2008

Syftet med examensarbetet var att undersöka effekterna av ozonering och filtrering på råvattnet från sjön Mälaren. Studien är utförd i en pilotanläggning på Lovö vattenverk, Stockholm Vatten AB, under våren 2004. En negativ effekt med den konventionella reningen är den stora konsumtionen av kemiska koagulanter. Kemikalieanvändningen leder till många transporter och processen producerar också ett slam som för närvarande transporteras till Mälaren. År 2001 byggdes en pilotanläggning på Lovö vattenverk för utveckling av nya processer, en av processerna är ozonering följt av olika filter. Ozonering har använts i Europa i många år som desinfektion i slutet av dricksvattenreningsprocessen. Intresset för ozonering har ökat markant sista åren och idag används ozonet också i andra steg i processen. Förutom desinfektion har ozonet andra fördelar, som oxidation av järn och magnesium, mikroflockning, reduktion av lukt och smak samt är bra på att reducera färgen på vattnet. Mikroflockningen leder till att kemikalieanvändningen kan minska och i vissa fall tas bort helt. Den här studien startade med en litteraturundersökning följd av försök med ozonering och filtrering i pilotanläggningen. De första undersökningarna sammanfattades med att ozonering följt av filtrering inte gav tillräckligt bra resultat och processen behöver ett komplement för att producera ett högklassigt vatten. Undersökningen fortsatte med laboratorieanalyser för att undersöka effekterna av olika kemiska koagulanter. Resultatet visade att järnsulfat tillsammans med kalcium var ett bra alternativ och en lägre kemikaliedos kunde användas. Efter implementering av kalcium och järnsulfat till pilotanläggningen testades olika ozondoser och olika järnsulfatdoser. Det bästa resultatet erhölls då man använde sig av en ozondos på 6 mg O3/l och en järnsulfatdos på 50-60 μmol/l. Denna mängd av järnsulfat är ca 60 % lägre än den dos som används vid den konventionella reningen på Lovö vattenverk. Olika filter används i pilotanläggningen och för att förbättra resultatet provades även ett Filtralite-filter som biofilter istället för GAC-filtret. Jämförelsen mellan Filtralite-filter och GAC-filter visade på stora skillnader i parametervärden i början av studietiden. När bakteriepopulationen ökade i Filtralite-filtret blev skillnaderna mindre och i slutet av undersökningstiden var parametervärdena likartade. Det slutliga resultatet indikerar att Filtralite-filter kan vara ett bra alternativ som biofilter. / This Master thesis was made to investigate the effects of ozonation and filtration on raw water from Lake Mälaren. The study was performed in lab-scale as well as in a pilot plant at Lovö waterworks, Stockholm Water Company during spring 2004. The conventional treatment at Lovö waterworks comes with a few disadvantages, such as large consumption of chemical coagulants. The chemical consumption leads to many transports and the treatment also produces a sludge which is, in present, returned to Lake Mälaren. In 2001 a pilot plant were built at Lovö waterworks for research on new treatment processes, and ozonation followed by filtration is one of them. Ozonation has been used in Europe for several years as disinfection at the end of the drinking water treatment process. The interests of ozonation has increased significantly in recent years and today the ozonation is used in other steps in the drinking water treatment process. Except for the disinfection, ozone has other benefits such as oxidation of iron and manganese, microflocculation, reduction of taste and odour and it is also effective to reduce the water colour. The microflocculation leads to the fact that less or no coagulants need to be used in the process. This study started with a literature overview followed by experiments on ozonation and filtration in the pilot plant. After the first experiments the conclusions were that the ozonation and filtration did not reach the same results as Lovö waterworks. To continue, jar tests were made to see the effects of different coagulants. The result indicated that ferric sulphate together with calcium addition (pH-adjustment) was a good alternative. Thereby a lower coagulant dose could be used. When ferric sulphate and calcium were implemented into the pilot plant, different ozone doses and ferric sulphate doses were tested. The best results occurred when an ozone dose of 6 mg O3/l and a ferric sulphate dose of 50-60 μmol/l were used. This amount of ferric sulphate is approximately 60 % lower than that for the conventional treatment at Lovö waterworks. To produce ozone electrons are needed and energy consumption increases with approximately 66 % compared to the conventional treatment. The decrease in chemical dose and increase in energy demand gives a decrease of the total cost with 10 % compared to the conventional treatment. The results indicate that the treatment with ozonation, calcium addition and ferric sulphate as a coagulant is an alternative to the conventional treatment. Different filters were used in the pilot plant and to improve the results a Filtralite-filter was tested instead of the GAC-filter as a bio filter. When comparing Filtralite-filter with the GAC-filter there were large differences between the filters at the beginning of the study. When the bacteria population in the Filtralite-filter had started to increase the differences became less. In the end of the experimental period the filters had similar conditions and Filtralite-filter may be a good alternative as a biofilter.

The presence of micropollutants, particularly pesticides, in surface waters across Canada has been of concern not only for their environmental impact, but also for their potential effects on human health and recalcitrant nature to conventional water treatment methods. Although ozone has been mainly applied for disinfection of drinking water, oxidation of trace organics by ozonation has been considered potentially effective. In an effort to meet increasingly stringent drinking water regulations, different solid catalysts have been used to enhance the removal of water contaminants by ozonation. In spite of the increasing number of data demonstrating the effectiveness of heterogeneous catalytic ozonation, the influence of different factors on the efficiency of micropollutants oxidation is still unclear.<p> In the present work, application of three solid catalysts in ozonation of two model micropollutants in pure water was examined using a laboratory-scale reaction system over a range of operating conditions. The three catalysts investigated were activated carbon, alumina, and perfluorooctyl alumina, and the two model micropollutants were the pesticides atrazine and 2,4-dichlorophenoxyactic acid. The effects of solution pH, presence of a radical scavenger, pesticide adsorption on catalyst, and catalyst dose on micropollutant removal were investigated. Solution pH was found to significantly influence the catalyst ability to decompose ozone into free hydroxyl radicals. The effect of these free radicals was markedly inhibited by the radical scavenger resulting in a negative impact on pesticides degradation. In general, the removal rate of pesticides was found to increase with increasing doses of catalyst.<p> In the ozonation process in the presence of activated carbon, atrazine removal rates increased four and two times when using a catalyst dose of 0.5 g L-1 at pH 3 and 7, respectively, whereas observed reaction rates for 2,4-D increased over 5 times in the presence of 1 × 10-4 M tert-butyl alcohol at pH 3. In the ozonation system catalyzed by 8 g L-1 alumina, the observed reaction rate constant of atrazine removal notably improved at neutral pH by doubling the micropollutant removal rate. For the pesticide 2,4-D in the presence of 1 × 10-4 M tert-butyl alcohol at pH 5, the observed removal rate was over ten times higher than that for the non-catalytic ozonation process using also using a catalyst dose of 8 g L-1. Modification of alumina to produce perfluorooctyl alumina resulted in a material able to significantly adsorb atrazine, while not exhibiting affinity for adsorption of 2,4-D. In spite of its adsorptive properties, perfluorooctyl alumina was found to enhance neither molecular ozone reactions nor ozone decomposition into hydroxyl radicals. Thus, the observed removal rates for atrazine and 2,4-D by ozonation in the presence of perfluorooctyl alumina did not increase significantly.

Ozonation is an efficient method to degrade refractory organics in textile wastewaters. In recent years, catalytic ozonation is applied to reduce ozone consumption and to increase chemical oxygen demand and total organic carbon (TOC) removal efficiencies. The ozonation of two industrial dyes, namely Acid Red-151 (AR-151) and Remazol Brilliant Blue R (RBBR) was examined separately both in a semi-batch reactor and also in a fluidized bed reactor (FBR) by conventional and catalytic ozonation with alumina and perfluorooctyl alumina (PFOA) catalysts. The conventional and catalytic ozonation reactions followed a pseudo-first order kinetics with respect to the dye concentration. The highest COD reductions were obtained in the presence of the catalysts at pH=13, with alumina for AR-151 and with PFOA for RBBR. Residence time distribution experiments were performed to understand the degree of liquid mixing in the reactor. The behaviour of the FBR was almost equivalent to the behaviour of one or two completely stirred tank reactors in series in the presence of the solid catalyst particles. The volumetric ozone-water mass transfer coefficients (kLa) were found at various gas and liquid flow rates and catalyst dosages in the FBR. A model was developed to find kLa in the reactor by comparing the dissolved O3 concentrations in the experiments with the model results. kLa increased significantly by the increase of gas flow rate. Higher catalysts dosages at the fluidization conditions yielded higher kLa values indicating higher rates of mass transfer. Dye ozonation experiments without catalyst and with alumina or PFOA catalyst were conducted at different conditions of the inlet dye concentration, gas and liquid flow rates, inlet ozone concentration in the gas, catalyst dosage, particle size and pH. The dye and TOC removal percentages were increased with the increase of gas flow rate and with the decrease of both the liquid flow rate and inlet dye concentration. The addition of the catalyst was beneficial to enhance the TOC degradation. The ozone consumed per liter of wastewater was much lower when the catalyst was present in the reactor. In terms of TOC removal and O3 consumption, the most efficienct catalyst was PFOA. According to the organic analysis, the intermediate by-products were oxalic, acetic, formic and glyoxalic acids in RBBR and AR-151 ozonation. The dye and dissolved ozone concentration profiles were predicted from a developed model and the model results were compared with the experimental results to obtain the enhanced kLa values. The presence of the chemical reaction and the catalysts in the FBR, enhanced the kLa values significantly. The enhancement factor (E) was found as between 0.97 and 1.93 for the non-catalytic ozonation and 0.96 and 1.53 for the catalytic ozonation at pH = 2.5. The dimensionless number of Hatta values were calculated between 0.04-0.103 for the sole ozonation of RBBR and AR-151 solutions. According to the calculated Ha values, the reaction occurred in the bulk liquid and in the film being called as the intermediate regime in the literature.

Denim production is one of the leading sub-sectors of textile industry which basically generates highly colored indigo dyeing effluents. In the present study, ozonation was applied to the indigo-dyeing effluent(COD=820 mg/L / color=5500 Pt-Co), and to the whole effluent from a denim-producing plant before(COD=2750 mg/L / color=3950 Pt-Co) and after(COD=800 mg/L,color=3700 Pt-Co) biological treatment for degradation/detoxification purposes. Ozonation was also tried in the wastewater of the plant(COD=3100 mg/L / color=4500 Pt-Co) that would be produced after some foreseen cleaner production measures / caustic recovery and reusing of dyeing process wastewater. When applied to indigo-dyeing wastewater / ozonation provided 95% color and 61% COD removals at 1320 mg/h ozone dose within 60 minutes The optimum pH was evaluated as 4 when indigo-dyeing wastewater exposed to ozonation at different pHs(1.6-12.3). On the other side, ozonation applied as pre-treatment to the plant effluent provided 86% color and 46% COD removals with 3240 mg/h ozone dose in 70 minutes. Less satisfactory results were obtained when ozonation was tried in the wastewater after measures, with 86% color and 31% COD removals at 3960 mg/h ozone dose in 80 minutes. When applied to the biologically-treated effluent / at 420 mg/h ozone dose and within 40 minutes, ozonation removed 47% of influent COD and 96% of influent color indicating better performance of ozonation in postoxidation. In order to assess possible improvements on ozonation with the addition of H2O2, different concentrations were tried, but no significant improvement was obtained. The improvement in BOD5/COD index was also determined for the ozonetreated plant effluent to measure the effects of ozonation on biodegradability and found out that BOD5/COD ratio has improved to 0.39 from 0.22.