This project explored the feasibility of using fungi in a constructed wetland for the treatment of pulp mill effluent. The effluent is high in dissolved lignins (some of which are chlorinated), which have proven very difficult to degrade biologically. Mindful of work done with the (terrestrial) white rot fungi, especially Phanerochaete chtysosporium, the question is asked, Is there a fungus which can tolerate submerged conditions while degrading a significant amount of dissolved lignins? Two fungal species with lignin-degrading capability were isolated from submerged films in a log pond. These fungi have been evaluated for decolorization potential under different environmental conditions. Results of laboratory experiments show that one of these fungi, identified as Acremonium sp., was capable of 44% decolorization of pulp mill effluent under sterile, submerged, room temperature conditions. The fungal decolorization was evaluated both in floating cultures and as a film inoculated on wood chips. In addition, bench-scale examination of the potential of this fungus to decolorize pulp mill effluent in non-sterile conditions was completed. / Graduation date: 1994

No description available.

This research investigated the relationships between molecular size and the TOC, TTHM, acid strength and color concentrations present in raw and coagulated water from Lake Washington. Three separate coagulants were utilized for investigation. There were: Al, Fe and Mg. Results indicated that the majority of the TOC, color and TTHM precursors were in the colloidal size range and removed by coagulation. The remaining TTHM precursors are mostly molecular and require a process other than coagulation for removal from the potable water before environmental standards are met.

Atualmente necessitam-se de processos de tratamento de efluentes que sejam mais sustentáveis em longo prazo, e com isso estão sendo desenvolvidos os processos oxidativos avançados (POAs). Estes processos apresentam a capacidade de mineralizar os poluentes, sem apenas transferi-los de fase, como ocorre com muitos métodos de tratamentos convencionais. A mineralização de poluentes, ou seja, a transformação de contaminantes orgânicos em dióxido de carbono, água e ânions inorgânicos, se baseia em reações de degradação que envolvem a geração de espécies altamente oxidantes, tais como o radical hidroxila (•OH). Durante o processo de fabricação, uma determinada quantidade de corante sempre é perdida e com frequência causa problemas ambientais. Os corantes afetam a natureza da água e inibem a penetração da luz solar nos rios reduzindo as suas atividades fotossintéticas. Devido a isso, os efluentes de indústrias que utilizam corantes em seus processos de produção necessitam de tratamentos adequados para a remoção desses contaminantes. Estudou-se então a aplicação da fotocatálise heterogênea (utilizando-se o TiO2 como fotocatalisador) com o objetivo de remover a cor de um efluente sintético contendo corantes de uma indústria de cosméticos (D&C Vermelho 6, Carmim e D&C Laranja 5). Para tal, realizou-se um planejamento experimental 23 em que se encontrou como ponto ótimo de tratamento os valores de 7,0, 0,5 g L-1 e 25°C para pH, concentração de TiO2 e temperatura, respectivamente, obtendo-se uma remoção de cor de 80% com 15 minutos de irradiação. Os experimentos cinéticos mostraram que a fotocatálise heterogênea segue um modelo de ordem 0,5 com constante de velocidade k = (7,2 ± 1,2) × 10-2 min-1 e R2 = 0,997. A fotólise segue um modelo de ordem 1, com constante de velocidade k = (8,9 ± 2,5) × 10-3 min-1 e R2 = 0,977. A diminuição dos valores de DQO, em aproximadamente 80%, demonstra que o efluente foi efetivamente oxidado. O valor encontrado na relação DQO/DBO5,20 para o efluente inicial demonstra que este não é biodegradável, porém após o tratamento, esta relação mostra que o efluente se tornou biodegradável. A remoção de COD, ou seja, a mineralização do efluente foi de aproximadamente 70% com 30 minutos de tratamento. Os valores encontrados de MOC confirmam o já descrito pela DQO, que o efluente foi realmente oxidado pelo tratamento. O efluente bruto apresentou uma leve ecotoxicidade enquanto que após o tratamento não houve ecotoxicidade alguma. Conclui-se com esse estudo que o método da fotocatálise heterogênea removeu a cor do efluente, tornou-o mais biodegradável, removeu sua ecototoxicidade e o mineralizou. / Currently, wastewater treatment processes that are more sustainable in the long term are needed, thus leading to the development of the advanced oxidation processes (AOPs). Those processes have the ability to mineralize pollutants, instead of just transferring them from one phase to another, as it is the case with many conventional treatment methods. The mineralization of pollutants, i.e. the transformation of organic contaminants into carbon dioxide, water and inorganic anions, is based on degradation reactions involving the generation of highly oxidizing species such as hydroxyl radical (•OH). During the manufacturing process, a certain amount of dye is always lost and often causes environmental problems. The dyes affect the nature of water and inhibit the penetration of sunlight into rivers, thus reducing their photosynthetic activity. Because of this, the wastewaters from industries that use dyes in their production processes require appropriate treatment for the removal of these contaminants. Therefore, it was studied the application of heterogeneous photocatalysis (using TiO2 as the photocatalyst) in order to remove the color of a synthetic wastewater containing dyes of the cosmetics industry (D&C Red 6, Carmin, and D&C Orange 5). For that purpose, an experimental design 23 was used and an optimal treatment condition was found: 7.0, 0.5 g L-1 and 25°C for pH, concentration of TiO2 and temperature, respectively, resulting in a color removal of 80% with 15 minutes of irradiation. Kinetic experiments showed that the heterogeneous photocatalysis follows a 0.5 order model, with a constant k of (7.2 ± 1.2) × 10-2 min-1 and R2 of 0.997. Photolysis followed a first order model, with a constant k of (8.9 ± 2.5) × 10-3 min-1 and R2 of 0.977. The COD decrease of approximately 80% shows that the effluent was effectively oxidized. The initial COD/BOD5, 20 ratio demonstrates that the effluent is not biodegradable, but after treatment, that ratio indicated that the effluent became biodegradable. The DOC removal, i.e. the mineralization of the effluent was approximately 70% with 30 minutes of treatment. The MOC confirmed that the effluent was actually oxidized by the treatment. The raw effluent had a slight ecotoxicity while after treatment it became non-toxic. It could be concluded that heterogeneous photocatalysis was able to remove the color of the effluent, to increase its biodegradability, to remove its ecotoxicity and to mineralize it.

A maioria dos efluentes pode ser facilmente tratada com reatores biológicos que oferecem boa eficiência na remoção da matéria orgânica. Contudo, a existência de compostos tóxicos ou de baixa biodegradabilidade dificulta o processo e, às vezes, impede que o mesmo seja feito. Na tentativa de minimizar a toxicidade e aumentar a biodegradabilidade, os Processos Oxidativos Avançados (POA) são uma alternativa viável. Os POA consistem na geração de fortes oxidantes \"in situ\" que reagem então com a matéria orgânica. O principal agente oxidante, gerado pelos POA, são os radicais hidroxila (•OH), que possuem um alto potencial de oxidação. Este trabalho teve por objetivo estudar, em escala laboratorial, a remoção de cor obtida pelo acoplamento de um reator de lodo ativado com a fotocatálise heterogênea (TiO2/UV), no tratamento do efluente de uma indústria de produtos de madeira, otimizando a concentração do catalisador, a temperatura e o pH, observando também a seqüência de tratamento, ou seja o reator fotocatalítico como pré- e pós-tratamento. O efluente e o lodo utilizados foram cedidos pela indústria de Faber-Castell em São Carlos. O tempo de retenção hidráulica (TRH) do reator de lodo ativado foi de 3 horas, com uma parada para a sedimentação de 30 minutos (tempos semelhantes aos utilizados pela empresa). A fotocatálise foi realizada em um reator encamisado com a irradiação de uma lâmpada de média pressão de Hg (250 W), a 20 cm da lâmina de líquido (volume efetivo de 100 mL), com agitação magnética de 45 rpm. O reator biológico utilizado no laboratório removeu boa parte da DQO do efluente, de 85-90% de remoção, porém não houve descoramento. Quando a fotocatálise foi utilizada como pós-tratamento, a remoção de cor foi de 93% em uma hora de irradiação e houve um total desaparecimento da ecotoxicidade do efluente. Ao se avaliar a fotocatálise como pré-tratamento do reator de lodo ativado, em uma hora de irradiação, houve pouca diminuição na intensidade de cor do efluente (60%) e a ecotoxicidade continuou alta. No entanto, ao se aumentar o tempo para 5 horas e 30 minutos houve um descoramento de quase 90%, somente com a fotocatálise. A cinética de descoramento, para o reator utilizado como pós-tratamento se ajustou a um modelo de primeira ordem com uma constante de velocidade (k) de (5,0 ± 0,57) × 10-2 min-1 e um R2 = 0,996. Quando o efluente bruto foi tratado primeiramente com a fotocatálise, a cinética de descoramento foi de ordem zero, com um R2 = 0,992, e uma constante de velocidade (k) de (2,60 ± 0,24) × 10-2 u.a. min-1. Conclui-se que o tratamento oxidativo avançado é uma ferramenta útil no descoramento do efluente estudado, tanto para pré ou pós-tratamento do reator biológico de lodo ativado. Porém, a melhor seqüência de reatores foi a que utilizou a fotocatálise como pós-tratamento, trabalhando com as condições, temperatura 25°C, pH 7 e concentração de dióxido de titânio de 2,0 g L-1, tendo havido uma redução de 93% da cor. Quando o reator fotocatalítico foi usado como pré-tratamento, nas condições pH 5,7, temperatura 25°C e concentração de titânio de 0,42 g L-1 TiO2, houve um descoramento de 60%. / Generally, wastewaters can be easily treated by biological reactors with a good efficiency regarding organic matter removal. However, the process can be impaired in the presence of compounds that are toxic or have low biodegradability. Advanced Oxidation Processes (AOPs) may be a choice to oxidize these compounds and minimize their toxicity and/or increase biodegradability. AOPs are based in the \"in situ\" generation of strong oxidants that reacts with the organic matter. The most important oxidant agent generated by AOPs is the hydroxyl radical (•OH), as they have a high oxidation potential. The aim of this work is to study, in laboratory scale, the decolorization achieved by the combination of an activated sludge reactor with heterogeneous photocatalysis (TiO2/UV), in the treatment of a wood\'s industry wastewater, optimizing catalyst concentration, temperature, and pH, also observing the treatment sequence, that is, photocatalysis prior or after the activated sludge reactor. The wastewater and the sludge were collected at Faber-Castell, São Carlos. The Hydraulic Retention Time (HRT) of the activated sludge reactor was 3 hours, with an interruption in the aeration of 30 minutes (same time used in the industry). Photocatalysis was carried out in a jacketed reactor with the irradiation of a medium pressure mercury lamp (250 W), away 20 cm from the wastewater surface (effective volume of 100 mL), magnetic stirred at 45 rpm. The biological reactor removed almost all COD of the effluent (85-90%), although color was not removed. When photocatalysis was used after the activated sludge reactor, color removal reached 93% in one hour of irradiation, as well as the complete detoxification of the wastewater. When photocatalysis as used as a pre-treatment, there was a color removal of 60% the ecotoxicity did not change. However, color removal increased to 90% with an irradiation time of 5 hours and 30 minutes. The photocatalytic decolorization kinetics (post-treatment) followed a first order model, with a constant (k) of (5.0 ± 0.57) × 10-2 min-1 and a R2 of 0.996. When the effluent was first treated with photocatalysis, the kinetics showed a zero order behavior, with a R2 = 0,992 and a of (2.60 ± 0.24) × 10-2 u.a. min-1. Photocatalysis is a good choice for removing the color of this effluent, regardless of the sequence tested. However, the best choice is to use photocatalysis prior to the biological treatement, as a 93% color removal was achieved, working with pH 7.0, 25°C and 2 g L-1 TiO2. Only 60% of color removal was observed when the wastewater was photocatalytic pretreated, with pH 5.7, 25°C, and 0.42 g L-1 TiO2.

by Stephen, Man-yuen Cheng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 124-141). / Abstract also in Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / List of Figures --- p.iv / List of Tables --- p.ix / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- The development of dyes --- p.1 / Chapter 1.2 --- The chemistry of azo dyes --- p.2 / Chapter 1.3 --- "Evaluation of dyes submitted under the ""Toxic Substances Control Act"" new chemicals programme" --- p.6 / Chapter 1.4 --- Environmental concerns of dyes --- p.7 / Chapter 1.5 --- Decolorization techniques --- p.11 / Chapter 1.5.1 --- Activated sludge process --- p.11 / Chapter 1.5.2 --- Chlorination --- p.12 / Chapter 1.5.3 --- Fenton's reaction --- p.13 / Chapter 1.5.4 --- Ozonation --- p.13 / Chapter 1.5.5 --- Adsorption by activated carbon --- p.13 / Chapter 1.5.6 --- Chemical flocculation --- p.14 / Chapter 1.5.7 --- Coagulation --- p.14 / Chapter 1.5.8 --- Advance Oxidation Process --- p.15 / Chapter 1.5.8a --- Photocatalytic activation --- p.17 / Chapter 1.5.8b --- Enhancement of reaction rates of photocatalytic reaction --- p.21 / Chapter 1.5.9 --- Biosorption of azo dyes by Pseudomonas sp. K-l --- p.23 / Chapter 1.6 --- Water pollution in Hong Kong --- p.24 / Chapter 1.7 --- Purpose of study --- p.24 / Chapter 2 --- Objectives --- p.27 / Chapter 3 --- Materials and Methods --- p.28 / Chapter 3.1 --- Materials --- p.28 / Chapter 3.1.1 --- Azo dyes --- p.28 / Chapter 3.1.2 --- Biosorbent --- p.28 / Chapter 3.1.3 --- Chemicals --- p.28 / Chapter 3.2 --- Photocatalytic reactor --- p.31 / Chapter 3.3 --- Determination of the peak absorbance of five azo dyes at different pH --- p.31 / Chapter 3.4 --- Determination of dye concentration by measuring at peak absorbance --- p.37 / Chapter 3.5 --- Determination of pseudo-first-order rate constant --- p.37 / Chapter 3.6 --- Effect of initial concentration of procion red MX-5B on photocatalytic degradation --- p.39 / Chapter 3.7 --- Effect of initial concentration of hydrogen peroxide on photocatalytic degradation of procion red MX-5B --- p.40 / Chapter 3.8 --- Effect of initial pH on the photocatalytic degradation of procion red MX-5B --- p.40 / Chapter 3.9 --- Effect of initial temperature on the photocatalytic degradation of procion red MX-5B --- p.40 / Chapter 3.10 --- Effect of titanium dioxide on the photocatalytic degradation of procion red MX-5B --- p.40 / Chapter 3.11 --- Effect of UV intensity in the photocatalytic degradation of procion red MX-5B --- p.41 / Chapter 3.12 --- Degradation kinetics of different dyes --- p.41 / Chapter 3.13 --- Degradation of 40 mg/L of procion red MX-5B under optimized conditions --- p.41 / Chapter 3.14 --- "Degradation of 1,000 mg/L of procion red MX-5B under optimized conditions" --- p.42 / Chapter 3.15 --- Temporal change of the concentration of procion red MX-5B in calcium alginate beads --- p.42 / Chapter 3.16 --- "Temporal change of the concentration of procion red MX-5B in alginate beads of 5,000 mg/L of Ti02" --- p.43 / Chapter 3.17 --- "Temporal change of the concentration of procion red MX-5B in alginate beads of 10,000 mg/L of Ti02" --- p.43 / Chapter 3.18 --- Effect of the concentration of titanium dioxide in alginate beads in the photocatalytic degradation of procion red MX-5B --- p.45 / Chapter 3.19 --- "Effect of hydrogen peroxide in the photocatalytic degradation of procion red MX-5B in 5,000 mg/L of Ti02-alginate beads" --- p.47 / Chapter 3.20 --- "Temporal change of the concentration of procion red MX-5B in alginate beads with 5,000 mg/L of Ti02" --- p.47 / Chapter 3.21 --- "Effect of biomass of Pseudomonas sp. K1 on the photocatalytic degradation of procion red MX-5B in alginate beads with 5,000 mg/L of Ti02" --- p.48 / Chapter 3.22 --- Diffuse reflectance-IR spectroscopic analysis of degradation product(s) --- p.49 / Chapter 3.23 --- Nuclear magnetic resonance (NMR) spectroscopic analysis of degradation products --- p.49 / Chapter 3.24 --- Toxicological evaluation of degradation products using Microtox® test --- p.51 / Chapter 4 --- Result --- p.54 / Chapter 4.1 --- Biosorption of dyes by Pseudomonas sp. K1 --- p.54 / Chapter 4.2 --- UV intensities of the eight Cole-Parmer UV lamps at 365 nm --- p.54 / Chapter 4.3 --- Determination of the peak absorbance of five azo dyes at different pH using scanning spectrophotometer --- p.54 / Chapter 4.4 --- Determination of dye concentration by measuring at peak absorbance --- p.66 / Chapter 4.5 --- Effect of initial concentration of procion red MX-5Bin photocatalytic degradation rate --- p.66 / Chapter 4.6 --- Effect of initial concentration of hydrogen peroxide on the photocatalytic degradation of procion red MX-5B --- p.73 / Chapter 4.7 --- Effect of initial pH on photocatalytic degradation of procion red MX-5B --- p.73 / Chapter 4.8 --- Effect of initial temperature on photocatalytic degradation of procion red MX-5B --- p.73 / Chapter 4.9 --- Effect of titanium dioxide on photocatalytic degradation of procion red MX-5B --- p.77 / Chapter 4.10 --- Effect of UV intensity on photocatalytic degradation of procion red MX-5B --- p.77 / Chapter 4.11 --- Photocatalytic degradation kinetics of different azo dyes --- p.77 / Chapter 4.12 --- Photocatalytic degradation of 40 mg/L of reactive red241 under optimized conditions --- p.77 / Chapter 4.13 --- Photocatalytic degradation of 40 mg/L procion red MX-5B under optimized conditions --- p.81 / Chapter 4.14 --- "Photocatalytic degradation of 1,000 mg/L of procion red MX-5B under optimized conditions" --- p.81 / Chapter 4.15 --- Temporal change of the concentration of procion red MX-5B in calcium alginate beads --- p.81 / Chapter 4.16 --- "Temporal changes of the concentration of procion red MX-5B in 5,000 mg/L of Ti02-alginate beads" --- p.85 / Chapter 4.17 --- "Temporal change of the concentration of procion red MX-5B in 10,000 mg/L of Ti02-alginate beads" --- p.85 / Chapter 4.18 --- Effect of the concentration of titanium dioxide in alginate beads in the photocatalytic degradation of procion red MX-5B --- p.89 / Chapter 4.19 --- "Effect of hydrogen peroxide in the photocatalytic degradation of procion red MX-5B in 5,000 mg/L of Ti02-alginate beads" --- p.89 / Chapter 4.20 --- "Temporal change of the concentration of procion red MX-5Bin alginate beads with 5,000 mg/L of Ti02" --- p.89 / Chapter 4.21 --- "Effect ofbiomass of Pseudomonas sp. K1 on the photocatalytic degradation of procion red MX-5B in 5,000 mg/L of Ti02-alginate beads" --- p.93 / Chapter 4.22 --- Degradation products analysis using diffuse reflectance-IR spectroscopy --- p.93 / Chapter 4.23 --- Degradation products analysis using nuclear magnetic resonance (NMR) --- p.101 / Chapter 4.24 --- Toxicological evaluation of degradation products using Microtox® test --- p.101 / Chapter 5 --- Discussion --- p.104 / Chapter 5.1 --- Biosorption of azo dyes in Pseudomonas sp. K-l --- p.104 / Chapter 5.2 --- Optimization of photocatalytic degradation of azo dyes --- p.105 / Chapter 5.2.1 --- Effect of initial concentration of procion red MX-5B on the photocatalytic degradation --- p.105 / Chapter 5.2.2 --- Effect of initial concentration of hydrogen peroxide on the photocatalytic degradation --- p.106 / Chapter 5.2.3 --- Effect of initial pH on the photocatalytic degradation --- p.107 / Chapter 5.2.4 --- Effect of initial temperature on the photocatalytic degradation --- p.108 / Chapter 5.2.5 --- Effect of titanium dioxide on the photocatalytic degradation --- p.109 / Chapter 5.2.6 --- Effect of UV intensity on the photocatalytic degradation --- p.110 / Chapter 5.2.7 --- Degradation kinetics of different dyes --- p.111 / Chapter 5.2.8 --- Optimized conditions for PCO of reactive red 241 and procion red --- p.112 / Chapter 5.3 --- Immobilization of titanium dioxide and Pseudomonas sp. K-l in alginate beads --- p.113 / Chapter 5.3.1 --- Temporal changes of the concentration of dye in alginate beads --- p.113 / Chapter 5.3.2 --- Effect of titanium dioxide in alginate beads in PCO --- p.114 / Chapter 5.3.3 --- Effect of hydrogen peroxide in alginate beads in PCO --- p.115 / Chapter 5.3.4 --- "Temporal change of dye concentration in alginate beads of 5,000 mg/L" --- p.115 / Chapter 5.3.5 --- Effect of biomass of Pseudomonas sp. K-l in alginate beads on the PCO of dye --- p.115 / Chapter 5.4 --- Diffuse reflectance IR spectroscopic analysis of degradation products --- p.116 / Chapter 5.5 --- 1HNMR analysis of degradation products --- p.119 / Chapter 5.6 --- Toxicological evaluation of degradation products using Microtox® test --- p.120 / Chapter 5.7 --- Application --- p.121 / Chapter 6 --- Conclusion --- p.122 / Chapter 7 --- References --- p.124 / Appendix 1 --- p.142 / Appendix 2 --- p.143

Existem muitos mananciais usados como fonte de abastecimento de água que apresentam cor verdadeira relativamente alta, devido à presença de substâncias húmicas (SH). Muitas estações de tratamento de água (ETA) apresentam problemas no processo de coagulação decorrentes da presença das SH. Com isso é necessário o uso de pré-oxidantes para reduzir a cor verdadeira da água. Quando emprega-se o cloro como oxidante ocorre a formação de subprodutos halogenados, que são prejudiciais a saúde humana. Para este estudo coletou-se água no Rio Itapanhaú - Bertioga/SP, a qual apresentou cor verdadeira na ordem de 400 uH. Para a extração das SHA empregou-se a resina XAD 8. Os extratos de SHA foram filtrados em membrana com poros de 0,45 µm e após utilizou-se a técnica de ultrafiltração (UF) para o fracionamento do material húmico em diferentes tamanhos moleculares aparente. As frações empregadas na caracterização foram: F1: menor que 0,45 µm, F2: entre 100 kDa e 0,45 µm, F3: entre 30 e 100 kDa, F4: entre 10 e 30 kDa, F5: entre 5 e 10 kDa. As frações foram caracterizadas por meio das técnicas de análise elementar, espectroscopia de ultravioleta/visível, infravermelho e ressonância magnética nuclear de 13C (RMN de 13C). Os resultados mostraram que as frações de menor tamanho molecular aparente (F3, F4 e F5) possuem maior conteúdo de carbonos alifáticos do que carbonos aromáticos e uma porcentagem relativamente alta de oxigênios ligados a grupamentos alquílicos e a ácidos carboxílicos. As frações de maior tamanho molecular aparente (F1 e F2) apresentaram maior grau de condensação de grupamentos aromáticos. No caso dos espectros de RMN de 13C, não foi possível verificar diferenças significativas nas diferentes frações de SHA. Verificou-se picos mais intensos na região de grupos carboxil e alifáticos e menos intenso na região dos aromáticos. Isso indica que nas SHA há maior conteúdo de grupamentos oxigenados e carbonos alifáticos. As amostras de água de estudo foram preparadas com água de poço artesiano e com as frações de diferentes tamanhos moleculares aparentes das SHA (F1: menor que 0,45 µm, F2: entre 100 kDa e 0,45 µm e F3: entre 30 e 100 kDa e F4\': menor que 30 kDa) com cor verdadeira aproximadamente de 100 uH e turbidez em torno de 0,5 uT. Para avaliar a influência dos diferentes tamanhos moleculares aparentes das SHA na eficiência da coagulação foram feitos ensaios em jartest empregando filtração direta descendente. Os coagulantes empregados neste estudo foram, o sulfato de alumínio e cloreto férrico, ambos como produto comercial líquido. Os diagramas de coagulação evidenciaram a influência do tamanho molecular aparente das SHA no processo de coagulação, quando empregou-se os coagulantes sulfato de alumínio e cloreto férrico. Para as águas de estudo preparadas com as frações de menor tamanho molecular aparente, foi necessário maior dosagem de coagulante para se obter remoção da cor aparente da água e mesmo assim, a remoção foi menor. A fração de menor tamanho molecular aparente (F4\') apresenta maior porcentagem de ácidos fúlvicos, e estes apresentam maior quantidade de grupos com carga negativa. Por isso, há necessidade de maior dosagem de coagulante para que ocorra uma eficiente remoção de cor aparente. / Water sources used to supply the public water system frequently have a relatively high true color intensity due to dissolved aquatic humic substances (AHS). In this study, water samples were collected from the Itapanhaú River (Bertioga, SP, Brazil), which exhibited a true color intensity in the order of 300 Hanzen units. XAD-8 resin was used to extract AHS. The AHS extract was filtered through a membrane with 0.45 µm pores, giving fraction F1, and this was separated by ultrafiltration into 4 apparent molecular size fractions of humic material: F2 from 100 kDa to 0.45 µm, F3 from 30 to 100 kDa, F4 from 10 to 30 kDa and F5 from 5 to 10 kDa. The fractions were characterized by elemental analysis and UV/Vis, infra-red (IR) and carbon 13 nuclear magnetic resonance (13C-NMR) spectroscopy. In general, the results showed that the smaller molecular size fractions (F3, F4 and F5) had a higher proportion of aliphatic than aromatic carbon atoms and a relatively high percentage of oxygen atoms bonded to alkyl groups and in carboxylic acids. Conversely, the apparently larger molecules (fractions F1 and F2) showed a higher content of aromatic groups. In the case of the 13C-NMR spectra, no significant differences could be detected among the fractions. There were stronger peaks in the carboxyl group and aliphatic carbon region and weaker peaks in the aromatic region, indicating that in the AHS as a whole, there is a greater content of oxygenated groups and aliphatic carbon atoms. Water from an artesian well was used to prepare experimental samples of the following molecular size fractions of AHS: F1 < 0.45µm, F2 from 100 kDa to 0.45 µm and F3: from 30 kDa to 100 kDa and F4\': < 30 kDa, with true color intensity around 100 Hazen units and turbidity around 5.0 NTU. To assess the influence of the apparent molecular size on the efficiency of coagulation, jar test were carried out, using direct filtration. The coagulants employed were aluminum sulfate and ferric chloride. The coagulation diagrams obtained with these products revealed the effects of the molecular size of the AHS on the coagulation process. For the experimental samples, fractions F3 e F4 \', a greater dose of coagulant was needed to remove the apparent water color around 5.0 Hanzen units and, even then, the amount removed was smaller. F4\' also had a higher proportion of fulvic acids, which exhibited a larger number of negatively-charged groups. For these reasons, a high dose of coagulant is necessary to achieve an efficient removal of apparent color.

No description available.

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.

Atualmente necessitam-se de processos de tratamento de efluentes que sejam mais sustentáveis em longo prazo, e com isso estão sendo desenvolvidos os processos oxidativos avançados (POAs). Estes processos apresentam a capacidade de mineralizar os poluentes, sem apenas transferi-los de fase, como ocorre com muitos métodos de tratamentos convencionais. A mineralização de poluentes, ou seja, a transformação de contaminantes orgânicos em dióxido de carbono, água e ânions inorgânicos, se baseia em reações de degradação que envolvem a geração de espécies altamente oxidantes, tais como o radical hidroxila (&bull;OH). Durante o processo de fabricação, uma determinada quantidade de corante sempre é perdida e com frequência causa problemas ambientais. Os corantes afetam a natureza da água e inibem a penetração da luz solar nos rios reduzindo as suas atividades fotossintéticas. Devido a isso, os efluentes de indústrias que utilizam corantes em seus processos de produção necessitam de tratamentos adequados para a remoção desses contaminantes. Estudou-se então a aplicação da fotocatálise heterogênea (utilizando-se o TiO2 como fotocatalisador) com o objetivo de remover a cor de um efluente sintético contendo corantes de uma indústria de cosméticos (D&C Vermelho 6, Carmim e D&C Laranja 5). Para tal, realizou-se um planejamento experimental 23 em que se encontrou como ponto ótimo de tratamento os valores de 7,0, 0,5 g L-1 e 25&deg;C para pH, concentração de TiO2 e temperatura, respectivamente, obtendo-se uma remoção de cor de 80% com 15 minutos de irradiação. Os experimentos cinéticos mostraram que a fotocatálise heterogênea segue um modelo de ordem 0,5 com constante de velocidade k = (7,2 &plusmn; 1,2) &times; 10-2 min-1 e R2 = 0,997. A fotólise segue um modelo de ordem 1, com constante de velocidade k = (8,9 &plusmn; 2,5) &times; 10-3 min-1 e R2 = 0,977. A diminuição dos valores de DQO, em aproximadamente 80%, demonstra que o efluente foi efetivamente oxidado. O valor encontrado na relação DQO/DBO5,20 para o efluente inicial demonstra que este não é biodegradável, porém após o tratamento, esta relação mostra que o efluente se tornou biodegradável. A remoção de COD, ou seja, a mineralização do efluente foi de aproximadamente 70% com 30 minutos de tratamento. Os valores encontrados de MOC confirmam o já descrito pela DQO, que o efluente foi realmente oxidado pelo tratamento. O efluente bruto apresentou uma leve ecotoxicidade enquanto que após o tratamento não houve ecotoxicidade alguma. Conclui-se com esse estudo que o método da fotocatálise heterogênea removeu a cor do efluente, tornou-o mais biodegradável, removeu sua ecototoxicidade e o mineralizou. / Currently, wastewater treatment processes that are more sustainable in the long term are needed, thus leading to the development of the advanced oxidation processes (AOPs). Those processes have the ability to mineralize pollutants, instead of just transferring them from one phase to another, as it is the case with many conventional treatment methods. The mineralization of pollutants, i.e. the transformation of organic contaminants into carbon dioxide, water and inorganic anions, is based on degradation reactions involving the generation of highly oxidizing species such as hydroxyl radical (&bull;OH). During the manufacturing process, a certain amount of dye is always lost and often causes environmental problems. The dyes affect the nature of water and inhibit the penetration of sunlight into rivers, thus reducing their photosynthetic activity. Because of this, the wastewaters from industries that use dyes in their production processes require appropriate treatment for the removal of these contaminants. Therefore, it was studied the application of heterogeneous photocatalysis (using TiO2 as the photocatalyst) in order to remove the color of a synthetic wastewater containing dyes of the cosmetics industry (D&C Red 6, Carmin, and D&C Orange 5). For that purpose, an experimental design 23 was used and an optimal treatment condition was found: 7.0, 0.5 g L-1 and 25&deg;C for pH, concentration of TiO2 and temperature, respectively, resulting in a color removal of 80% with 15 minutes of irradiation. Kinetic experiments showed that the heterogeneous photocatalysis follows a 0.5 order model, with a constant k of (7.2 &plusmn; 1.2) &times; 10-2 min-1 and R2 of 0.997. Photolysis followed a first order model, with a constant k of (8.9 &plusmn; 2.5) &times; 10-3 min-1 and R2 of 0.977. The COD decrease of approximately 80% shows that the effluent was effectively oxidized. The initial COD/BOD5, 20 ratio demonstrates that the effluent is not biodegradable, but after treatment, that ratio indicated that the effluent became biodegradable. The DOC removal, i.e. the mineralization of the effluent was approximately 70% with 30 minutes of treatment. The MOC confirmed that the effluent was actually oxidized by the treatment. The raw effluent had a slight ecotoxicity while after treatment it became non-toxic. It could be concluded that heterogeneous photocatalysis was able to remove the color of the effluent, to increase its biodegradability, to remove its ecotoxicity and to mineralize it.