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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
451

Tratamento oxidadtivo e redutivo de efluentes industriais visando a destruição de Percloroetileno (PCE) e Metil Isobutil Cetona (MIBK) / Oxidative and reductive treatment of industrial wastewaters for destruction of perchlorethylene (PCE) and methyl isobutyl ketone (MIBK)

Rizzo, Ricardo Buono 08 April 2005 (has links)
Orientador: Wilson F. Jardim / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-05T11:13:59Z (GMT). No. of bitstreams: 1 Rizzo_RicardoBuono_M.pdf: 2115132 bytes, checksum: 7aea5731fd5c49b280db63fc4f1f2aaf (MD5) Previous issue date: 2005 / Resumo: Neste trabalho foi estudada a eliminação dos solventes Percloroetileno (PCE) e Metil Isobutil Cetona (MIBK), em efluentes líquidos de uma planta industrial. A análise pelo período de 4 meses, mostrou valores médios de 17.565 mg/L de PCE e 41.340 mg/L de MIBK. Como tratamento inicial, foi avaliada a eficiência de um POA empregando o reagente de Fenton (H2O2 e Fe). No teste inicial com uma solução sintética a 5000 mg/L, de PCE, foi obtida uma destruição superior a 99% dentro de um período de 6 horas, empregando uma concentração de 1000 mg/L de H2O2 a 60% (m/m), sendo que a reação apresentou uma cinética de 1 ordem (k = 1,94 x 10 s). Para amostras do efluente, foram obtidas eficiências de destruição variáveis com as concentrações iniciais e dosagens aplicadas dos reagentes. Empregando dosagens de H2O2 : Fe (9000 mg/L : 900 mg/L), para uma amostra contendo 10.546 mg/L de PCE e 6.704 mg/L de MIBK, foram obtidas eficiências de remoção superiores a 99,9%, dentro de períodos de 3 horas de tratamento, com cinéticas variáveis entre 1 ordem e 2 ordem. A otimização dos reagentes demonstrou a necessidade de aplicar dosagem correta para obter a destruição total do PCE e MIBK. Com relação ao pH, foi observado que o ajuste para pH 3,0 promoveu um aumento da eficiência da destruição, contra o teste em pH 2,0. Para a maior dosagem de reagentes, observou-se um aumento de 6% na destruição. Paralelamente foi avaliada a eficiência da eliminação do PCE pelo processo de descloração redutiva por Ferro Zero Valente, com remoções de até 89,4%, e a geração do subproduto tricloroetileno. Finalmente, como proposta de trabalho foi estudada a combinação do processo redutivo (Ferro Zero Valente) e oxidativo (Fenton) como uma alternativa para a maximização da eficiência de tratamento e minimização de custos, visto que possibilita a destruição completa tanto do PCE quanto do MIBK dentro do período de 2 horas de tratamento, eliminando ainda a necessidade da adição de ferro. / Abstract: This work is about the removal of Perchloroethylene (PCE) and MethylIsobutyl Ketone (MIBK) in a liquid effluent from an industrial plant. A 4-month analysis has shown average levels of 17,565 mg/L of PCE and 41,340 mg/L of MIBK. Initially, the AOP using Fenton's reagent (H2O2 and Fe) was evaluated. First, a synthetic solution containing 5,000 mg L of PCE was tested and reached elimination greater than 99% within 6 hours of treatment, using a concentration of 1,000 mg/L of H2O2 at 60% (w/w). In this test, a 1 order kinetics (k = 1,94 x 10-4 s-1) was observed. For wastewater samples, using dosages of H2O2 : Fe (9000 mg L:mg L), an elimination destruction above 99,9% was obtained within 3 hours of treatment, for a sample containing 10,546 mg L of PCE and 6,704 mg L of MIBK. Data showed variations between 1st and 2nd order kinetics. Optimization of reactant dosage showed that it is necessary to apply the right dosage to get total elimination of PCE and MIBK. Regarding pH, it was observed that adjustment to pH 3 always gives better results than pH 2. For the greatest dosage of chemicals, an improvement of 6% in the destruction was observed. Simultaneously, a PCE elimination by reductive dechlorination using Zero Valent Iron with removal efficiencies up to 89.4% and generation of trichloroethylene as a by-product was evaluated. Finally, a combination of Oxidative (Fenton) and Reductive (Zero Valent Iron) processes was proposed as an alternative to improve the treatment efficiency and reduce costs. The application of this treatment made it possible to reach complete removal of both contaminants within 2 hours of treatment, besides allowing the elimination of the iron added. / Mestrado / Quimica Analitica / Mestre em Química
452

Tratamento de esgoto sanitario em reator anaerobio preenchido por casca de coco verde (Cocos nucifera) combinado com filtro de areia / Wastewater treatment through an anaeroboc filter filled up with coco nuts (cocos nucifera) combined with sand filter

Cruz, Luana Mattos de Oliveira, 1985- 13 August 2018 (has links)
Orientador: Ronaldo Stefanutti / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-13T07:16:42Z (GMT). No. of bitstreams: 1 Cruz_LuanaMattosdeOliveira_M.pdf: 2567384 bytes, checksum: 517d8663924f9e32a90ec5b64ae951c8 (MD5) Previous issue date: 2009 / Resumo: O desenvolvimento de sistemas de tratamento de esgoto, eficientes e adaptáveis às condições econômicas e estruturais de uma região seria uma opção para diminuir o problema da escassez de água, já que o efluente poderia ser reutilizado ou descartado nos corpos hídricos. Ainda, com o esgotamento sanitário, os problemas de saúde pública e do meio ambiente seriam menos agravantes. Frente a esta situação, o objetivo deste projeto foi estudar um sistema para o tratamento de esgoto doméstico de pequenas comunidades, composto por filtros anaeróbios seguidos por filtros de areia. Avaliou-se o desempenho de dois filtros anaeróbios com fluxos ascendentes e preenchidos com cascas de coco verde (Cocos nucifera) e de quatro filtros de areia com espessura de 0,75m. A partida dos reatores anaeróbios foi diferente pois um deles foi inoculado. O Tempo de Detenção Hidráulico (TDH) estudado variou de 12 horas até 3 horas. Nos quatro filtros de areia foram aplicadas diferentes taxas hidráulicas (300, 400, 500 e 600 Lm-2dia) com a finalidade de se encontrar a capacidade limite de aplicações diárias, mantendo seu efluente com qualidade compatível a legislações brasileiras, como o CONAMA 357. A avaliação dos reatores anaeróbios, do meio suporte e das taxas de aplicação nos filtros de areia foi realizada com a análise semanal do esgoto bruto, dos efluentes anaeróbios e dos efluentes dos filtros de areia quanto a parâmetros físicos, químicos e biológicos, conforme os procedimentos do Standard Methods for the Examination of Water and Wastewater. Os filtros anaeróbios mostraram-se estáveis frente a mudanças do TDH e a remoção de material orgânico foi em torno de 64% evidenciando que as cascas de coco verde podem ser utilizadas como meio suporte. Os filtros de areia puderam remover cerca de 80% da matéria orgânica e dos SST e, aproximadamente, 100% da turbidez. Além disso, apresentaram grande capacidade de aeração e nitrificação, gerando um efluente com 82% de concentração de nitrato em relação à concentração de nitrogênio total. Como os resultados foram satisfatórios, comprova-se que é possível a aplicação de maiores taxas hidráulicas nos leitos de areia. / Abstract: The development of efficient wastewater treatment systems, which are also adapted to the economic and structural conditions of a village, would be an option to decrease the lack of water problem since the effluent could be reused or discharged into receiving waters. Moreover, with wastewater system, health and environmental problems would be less frequent. For this reason, the aim of this investigation was to study a wastewater treatment system for small villages constituted by the combination of upflow anaerobic filters followed by sand filters. The performance of two upflow anaerobic reactors filled with coco nuts (Cocos nucifera) and four sand filters (0.75m deep) was evaluated. The anaerobic filters' staring up were different since one of them was inoculated. The hydraulic retention time (HRT), which was studied, varied from 12 to 3 hours. On the four sand filters, the anaerobic effluent was disposed in different frequencies of application (300, 400, 500 and 600 Lm-2dia-1) in order to estipulate the diary application limit capacity to keep the effluent quality according to Brazilian laws, like CONAMA 357. To evaluate the anaerobic reactors, the support and the frequency of application on the sand filters, weekly, sewage, anaerobic and final effluent were analyzed through physical, chemical and biological parameters, according to Standard Methods for the Examination of Water and Wastewater. Anaerobic reactors were stable even when HRT was modified and organic material removing was around 64% showing that the coco nuts can be used as a support. The sand filters could remove about 80% of organic matter and TSS and, approximately, 100% of turbidity. Besides, these filters showed a great capacity of aeration and nitrification producing an effluent with 82% of nitrate concentration from the total nitrogen concentration. As the results were satisfactory, it can be confirmed the possible higher frequencies of application in sand filters. / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil
453

Biofotonica aplicada ao monitoramento microbiologico de efluentes sanitarios / Spontaneous light emission applied to microbiological wastewater monitoring

Santos, Samuel Ricardo dos, 1980- 02 May 2010 (has links)
Orientadores: Jose Euclides Stipp Paterniani, Cristiano de Mello Gallep / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-15T12:44:58Z (GMT). No. of bitstreams: 1 Santos_SamuelRicardodos_M.pdf: 4212906 bytes, checksum: ecb5c9bc690bf3b7b2b146796b9c61a1 (MD5) Previous issue date: 2010 / Resumo: As bactérias do grupo coliformes têm sido amplamente empregadas no monitoramento da qualidade da água, com o uso da Escherichia coli como microrganismo indicador de contaminação fecal. Os métodos atuais de detecção apresentam no mínimo 18 h para obtenção de resultados e em outros processos, que incluem testes bioquímicos, podem chegar até 48 h para análise conclusiva. A importância de uma rápida detecção de coliformes e Escherichia coli aplicada à qualidade e segurança da água torna-se óbvia e necessária. O uso de medidas da luz, presente em seres vivos, surge como metodologia promissora aplicada ao monitoramento microbiológico das águas, podendo gerar resultados em tempo reduzido de análise. No presente trabalho avaliou-se o potencial da técnica biofotônica aplicada ao monitoramento de efluentes sanitários em seu parâmetro microbiológico, através da detecção de emissão ultrafraca de luz em testes envolvendo coliformes. A metodologia baseou-se no acompanhamento dos padrões de emissão de luz em câmara escura com o uso de efluente doméstico, antes e após tratamento, incubados em meio nutritivo. O controle foi efetuado com o uso de cepa de Escherichia coli (ATCC 25922), incubada em meio nutritivo, tendo seu crescimento monitorado por emissão de luz. Os resultados com cepa e efluente doméstico incubados em substrato cromogênico apresentaram melhores correlações entre crescimento de microrganismos e emissão de luz, em contraste com ensaios efetuados com meio EC e meio nutritivo a base de lactose e lauril triptose. Os dados demonstram que o monitoramento microbiológico pode ser efetuado através da técnica biofotônica, com a identificação da emissão de luz por microrganismos com pelo menos três horas de análise em substrato cromogênico e pelo menos doze horas em meio EC e Presença/Ausência (P/A). / Abstract: The coliform bacteria have been widely used in water quality monitoring, using Escherichia coli as indicator of faecal contamination. Current standard methods for of coliforms and Escherichia coli detection take 18-h minimum and the complete testing process, including confirmatory biochemical tests, may require at least 48 hours. The importance of rapid detection of coliforms and Escherichia coli, regarding to the quality and safety of water, is obvious and necessary. The spontaneous light emission of living systems emerge as a promising methodology that applied to microbiological in monitoring water can lead to shortterm analysis. The present study evaluated the potential of biophoton measurements applied to wastewater monitoring by using ultraweak light emission in coliform tests. The procedure is based on photon-counting measurements inside a dark-chamber, of wastewater samples, before and after treatment, inoculated in nutrient medium. Strain of Escherichia coli (ATCC 25922) was used in control tests by monitoring the light emission in nutrient medium. The results for strain and wastewater incubated in chromogenic substrate show better correlation between microbial growth and light emission, in contrast to experiments with EC Broth and Presence/Absence nutritive medium. The data show that microbiological monitoring can be done by photon-counting with at least three hours in chromogenic substrate and at least twelve hours with EC and Presence/Absence Broth. / Mestrado / Agua e Solo / Mestre em Engenharia Agrícola
454

Desenvolvimento e avaliação do desempenho de flotador alternativo para tratamento de agua residuaria sintetica da industria de alimentos / Development and evaluation of an alternative flotador to treat synthetic dairy wastewater

Santos, Jacqueline Fiuza dos 09 May 2008 (has links)
Orientador: Ranulfo Monte Alegre / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-11T12:03:56Z (GMT). No. of bitstreams: 1 Santos_JacquelineFiuzados_D.pdf: 944991 bytes, checksum: be9d470f417d964bcd97a0494f5f0412 (MD5) Previous issue date: 2008 / Resumo: O presente trabalho teve como objetivo desenvolver e avaliar o desempenho de um flotador utilizando uma pedra porosa inserida na garganta de um Venturi modificado para formação de bolhas de ar, utilizadas para flotar partículas suspensas de leite após ajuste do pH a aproximadamente 4,6, no qual ocorre o ponto isoelétrico das proteínas do leite implicando na precipitação das mesmas. O uso do Venturi dispensa o uso de compressores e válvulas de redução de pressão para formação das bolhas de ar, essenciais na operação de flotação. Foram realizados ensaios em sistema descontínuo e contínuo para diferentes tempos de flotação, diferentes vazões de reciclo de água residuária (QL) e de ar (Qar). A eficiência do sistema foi avaliada através da determinação da concentração de sólidos suspensos de leite floculado no afluente e no efluente do equipamento. Os resultados encontrados demonstraram que o flotador foi eficiente para remoção de partículas sólidas floculadas de água residuária láctea sintética tanto em sistema descontínuo quanto em contínuo, apresentando, respectivamente, eficiências máximas de separação de sólidos em torno de 100% e 70%. Portanto, os experimentos realizados em sistema descontínuo apresentaram melhores eficiências de separação de sólidos / Abstract: The objective of this work was to develop and evaluate the performance of a flotator with a porous stone inserted in the modified Venturi throat for bubbles air formation, used to float suspended particles of milk after settlement of the pH to approximately 4.6, in which occurs the milk proteins isoeletric point implying in the proteins precipitation. The use of the Venturi excuses the use of steam and pressure reduction valves for bubbles air formation, essential in the flotation. It was carried out experiments in batch and continuous system for different flotation times, different wastewater recycle flow rates (QL) and air flow rates (Qar). The system efficiency was evaluated through the determination of the suspended solids concentration of the flocculated milk in the affluent and effluent of the equipment. The results found showed that the flotation equipment was efficient for flocculated solid particles removal from synthetic milky wastewater in batch and continuous system, with maximum solids separation efficiencies around 100% and 70%, respectively. Therefore the experiments carried out in batch system presented better solids removal efficiencies / Doutorado / Doutor em Engenharia de Alimentos
455

Efeitos da emissÃo dos efluentes domÃsticos na proliferaÃÃo de Aeromonas spp. em Ãguas de superfÃcie e pescado do estuÃrio do Rio Bacanga, SÃo Luis â MaranhÃo / The issuance of domestic sewage in the proliferation of Aeromonas spp. in surface water and fish of the estuary of the River Bacanga, SÃo Luis - MaranhÃo

Andrà Gustavo Lima de Almeida Martins 07 March 2005 (has links)
Universidade Federal do Cearà / Para a detecÃÃo de Aeromonas foram coletadas 90 amostras de Ãgua de superficie e 30 de peixes no estuÃrio do rio Bacanga em SÃo LuÃs/MA, no perÃodo de marÃo a outubro de 2004. As amostras foram submetidas, simultaneamente, ao mÃtodo de plaqueamento direto em Agar Gelatina Fosfato Sal (Agar GSP acrescido de 20flglrnL de ampicilina) para a contagem (UFC/rnL ou g) e a determinaÃÃo do NÃmero Mais ProvÃvel (NMP/100rnL ou g) pela tÃcnica dos tubos mÃltiplos, utilizando-se o Caldo Tripticase Soja (Caldo TSB com 20flglrnL de ampicilina). As espÃcies de peixes analisadas foram: Bagre (Pimelodus maculatus), Tainha (Mugil cephalus), Solha (Pleuronectes platessa), Prata (Hemigrammus rodwayi), Sardinha (Opisthonema oglinum). Os resultados obtidos retratam uma ampla disseminaÃÃo de Aeromonas no estuÃrio. Para as amostras de Ãgua e peixes as contagens variaram de 40 a 1,3x108 UFC/rnL e de 3,2x102 a 5,8x106 UFC/g respectivamente, sendo que os maiores Ãndices foram obtidos nos pontos prÃximos Ãs emissÃes de esgotos domÃsticos. Os valores para o NMP/lOOrnL de Ãgua oscilaram entre 2,3x104 e 1,6x107 e de 230 a 24000/g para peixe. Os maiores Ãndices de Aeromonas foram constatados no mÃs de maior intensidade de chuvas, abril, e os menores em outubro, correspondente ao pico de estiagem na regiÃo, evidenciando assim uma possÃvel sazonal idade na incidÃncia da bactÃria no ambiente estudado. Das 751 cepas isoladas das amostras de Ãgua, 582 foram positivas para Aeromonas, sendo que 52,70. 10 eramA. caviae, 23,8% A. hydrophila, 19,5%,A. veronii e 3,7%A. sobria. Para as isoladas do pescado (245 cepas) 184 foram identificadas como Aeromonas sendo 43,4% de A. caviae, 28,2% de A. hydrophila, 26,6% A. veronii e 1,6% de A. sobria. Com relaÃÃo aos parÃmetros fisico-quÃmicos medidos nas Ãguas de superficie do estuÃrio do rio Bacanga, apenas a temperatura, a salinidade e o pH, tiveram correlaÃÃes significativas. De modo geral, as cepas de Aeromonas sp. foram sensÃveis a maioria dos antimicrobianos testados, com exceÃÃo de ampicilina, ao qual 100% das cepas foram resistentes. / For the detection of Aeromonas were collected 90 samples of surface water and 30 fish in the estuary of the river in St. Louis Bacanga / MA in the period March to October 2004. The samples were submitted, while the method of direct plating on Gelatin Phosphate Salt Agar (Agar GSP plus 20flglrnL of ampicillin) to count (CFU / g or RNL) and the determination of Most Probable Number (NMP/100rnL or g) by the multiple tube technique, using trypticase soya broth (TSB broth with ampicillin to 20flglrnL). The fish species examined were: Bagre (Pimelodus maculatus), Mullet (Mugil cephalus), plaice (Pleuronectes platessa), Silver (Hemigrammus Rodway), Sardines (Opisthonema oglinum). The results show a wide spread of Aeromonas in the estuary. For samples of water and the fish counts ranged from 40 to 1.3 x108 CFU / NLOs and 3.2 x102 to 5.8 x106 CFU / g respectively, and the highest rates were obtained at points close to the emission of domestic sewage. The values for the NMP / lOOrnL of water ranged from 2.3 x104 and 1.6 x107 and 230 to 24,000 / g for fish. The highest rates of Aeromonas were observed in the month of highest intensity of rainfall, April, and lowest in October, corresponding to the peak of drought in the region, thus a possible seasonal effect in the age of the bacteria in the environment studied. Of the 751 strains isolated from water samples, 582 were positive for Aeromonas, with 52.70. 10 were. caviae, 23.8% A. hydrophila, 19.5%, A. A. veronii and 3.7% sobria. For the isolated fish (245 strains) 184 were identified as Aeromonas and 43.4% of A. caviae, 28.2% of A. hydrophila, 26.6% A. veronii and 1.6% of A. sobria. Regarding the physico-chemical parameters measured in surface waters of the estuary of the river Bacanga, only the temperature, salinity and pH, had significant correlations. In general, the strains of Aeromonas sp. were sensitive to most antimicrobials tested, except ampicillin, to which 100% of strains were resistant.
456

Eletroflotação aplicada ao tratamento de esgoto sanitário / Electroflotation applied to the sewage treatment

Joel Alonso Palomino Romero 15 October 2009 (has links)
Este trabalho avaliou o desempenho de um reator piloto de eletroflotação, que utilizou placas de alumínio em arranjo monopolar em paralelo como eletrodos de sacrifício para o tratamento de esgoto sanitário. O processo foi auxiliado pela adição de cloreto de sódio para melhorar a condutividade do esgoto bruto. Preliminarmente, testaram-se em ensaios de eletroflotação em bancada, densidades de corrente entre 8 e 21 A m-2 e determinou-se que o melhor desempenho na diminuição da turbidez era obtido aplicando uma densidade de corrente próxima a 13,8 A m-2. Posteriormente foram conduzidos ensaios no reator piloto para determinar a vazão e a dosagem de cloreto de sódio. A partir destes foram determinadas as variáveis operacionais, que foram: densidade de corrente de 14,2 A m-2, vazão de 0,33 m3 h-1, dosagem de cloreto de sódio de 0,5 g L-1 e tempo de detenção hidráulica de 18,2 min. O reator piloto de eletroflotação foi testado com duas configurações de posição dos eletrodos: transversal e paralelo ao fluxo. O melhor desempenho do reator de eletroflotação foi obtido com o arranjo em paralelo ao fluxo; este permitiu aumentar a vazão para 0,5 m3 h-1 e diminuir a dosagem de cloreto de sódio para 0,25 g L-1. Amostras de esgoto bruto e esgoto eletroflotado obtidas do reator operando em ambas as configurações da posição dos eletrodos foram coletadas e submetidas a análises físico-químicas. Estas análises permitiram determinar a eficiência da remoção de: cor verdadeira em 82% e 86% para os arranjos das placas em transversal e paralelo ao fluxo respectivamente, da mesma forma a turbidez em 96% e 93%, sólidos totais em 90% e 97%, carbono orgânico total em 60% e 58%, nitrogênio amoniacal em 42% e 51%, demanda bioquímica de oxigênio em 91%, demanda química de oxigênio em 89% concentração de óleos e graxas em 100%, fósforo total em 99%, coliformes termotolerantes e E coli. em duas unidades log e aumento de oxigênio dissolvido em 400% e 366%. Uma análise de espectroscopia de emissão atômica também foi feita para determinar a concentração de espécies metálicas e não metálicas. Esta análise revelou que as espécies encontravam-se em concentrações baixas e em alguns casos abaixo do limite de detecção, mas após tratamento por eletroflotação estas concentrações também sofreram diminuição. O cálculo da massa teórica de alumínio desgastada nos ânodos foi calculada em 4 g m-3, a quantidade de lodo gerado foi de 0,16 m3 e os custos operacionais totais estimados em R$0,64 e R$0,38 kw h m-3 com o reator operando nas configurações de posição dos eletrodos transversal e paralelo respectivamente. Os valores dos parâmetros observados nas análises físico-químicas do esgoto eletroflotado se encontram dentro dos limites estipulados pela Resolução CONAMA No. 357 para o lançamento de efluentes e para águas de classe 3. A comparação das eficiências de remoção alcançadas pela eletroflotação com eficiências típicas de remoção dos principais poluentes nos esgotos domésticos, alcançadas por diversos métodos de tratamento permite afirmar que a eletroflotação é uma técnica eficiente no tratamento de esgoto sanitário e é economicamente viável, por isto deve ser considerada como uma alternativa aos métodos de tratamento convencionais. / This study assessed the performance of a domestic sewage treatment pilot unit of electroflotation, which used aluminum plates in a monopolar parallel arrange as sacrifice electrodes for sewage treatment. The process was aided by the addition of sodium chloride to improve the conductivity of the raw sewage. First, it was tested in lab-scale experiments, current densities between 8 and 21 A m-2. The best performance in the turbidity decrease was obtained by applying a current density close to 13.8 A m-2. Later experiments were conducted in the pilot reactor to determine the flow rate and dosage of sodium chloride. From these, the operational variables were determined, which were: current density of 14.2 A m-2, a flow rate of 0.33 m3 h-1, sodium chloride dosage of 0.5 g L-1 and hydraulic detention time of 18.2 min. The electroflotation pilot reactor was tested with two sets of electrode position: transverse and parallel to the flow. The best performance of the electroflotation reactor was achieved with the parallel arrangement; this allowed increase the flow to 0.5 m3 h-1 and reduce the amount of sodium chloride to 0.25 g L-1. In comparison to raw sewage, the treated effluent presents a decrease of 82% and 86% for the true color for the arrangement of plates in transverse and parallel respectively, just as a decrease in the turbidity by 96% and 93%, total solids by 90% and 97% total organic carbon by 60% and 58%, nitrogen by 42% and 51% biochemical oxygen demand at 91%, chemical oxygen demand at 89%, oils and greases concentration by 100 %, total phosphorus by 99%, fecal coliforms and E. coli. in two log units and increased dissolved oxygen in 400% and 366%. An atomic emission spectroscopy analysis was also done to determine the concentration of metal and non-metallic species. This analysis revealed that the species were in low concentrations and in some cases below the detection limit, but after electroflotation treatment these concentrations also decrease. The calculation of the theoretical mass of the worn aluminum anodes was estimated in 4 g m-3, the amount of sludge generated was 0.16 m3 and the total operating costs estimated at R$ 0.64 and R$ 0.38 kw h m-3 with the reactor operating in transverse and parallel settings of electrode position, respectively. The values of the parameters observed in the physicochemical analysis of electroflotated sewage are within the limits set by CONAMA Resolution No. 357 for the release of effluents and for Class 3 waters. Comparison of removal efficiencies achieved by electroflotation with typical removal efficiencies of major pollutants in domestic sewage, achieved by various treatment methods suggest that the electroflotation is an efficient technique for the treatment of sewage and is economically viable, therefore must be considered as an alternative to conventional treating methods.
457

Tratamento eletroquímico e eletroquímico foto-assistido na degradação de efluentes da indústria têxtil / Electrochemical and photo-assisted electrochemical degradation of textile wastewater

Patricia Aparecida Alves 13 September 2010 (has links)
Este trabalho apresenta o estudo da degradação eletroquímica e eletroquímica foto-assistida de efluentes têxteis industriais usando ânodos dimensionalmente estáveis (ADE). As amostras analisadas foram coletadas diretamente do tanque de equalização (efluente bruto) e do tanque final (efluente biologicamente tratado) cedidas pela empresa Toalhas São Carlos, de São Carlos, São Paulo. As degradações foram realizadas em uma célula de fluxo do tipo filtro prensa com eletrodo ADE comercial (composição nominal Ti/Ti0,7Ru0,3O2) sob recirculação constante. A fim de avaliar os melhores parâmetros de degradação, foram estudadas as influências do tipo de eletrólito suporte (NaCl e Na2SO4), concentrações de NaCl (0,05 a 0,30 mol L-1), densidade de corrente (10 a 120 mA cm-2) e pH (4, 7, 8, 9 e 12). Após definição dos melhores parâmetros, novas amostras do tanque de equalização foram coletadas, em dias alternados para avaliar a influência da composição do efluente. Ensaios eletroquímicos foto-assistidos foram realizados nas mesmas condições que os ensaios eletroquímicos visando a comparação dos métodos. Caracterizações do ADE foram realizadas por voltametria cíclica na ausência e presença de efluente e de luz. Durante as eletrólises de 2 horas, amostras foram coletadas e analisadas por espectroscopia UV vis, carbono orgânico total (COT) e demanda química de oxigênio (DQO). Análises da formação de subprodutos foram realizadas pelos métodos de fitotoxicidade e organoclorados que mostraram uma maior toxicidade após 10 horas de eletrolise. Avaliação do residual de cloro e cloreto complementaram os estudos. Observou-se que a degradação é mais efetiva pelo método eletroquímico foto-assistido em relação ao método eletroquímico. Também, a adição de NaCl favorece a degradação pela formação de agentes oxidantes, ao contrário do Na2SO4. Nas maiores concentrações de NaCl e densidades de corrente implicam em maior remoção de cor e DQO. Contudo no estudo com diferentes valores de pH, os melhores resultados foram em pH mais baixo. Considerando todos os resultados, os melhores parâmetros para degradação de efluentes têxteis industriais foram densidade de corrente de 40 mA cm-2, pH 8, 0,15 mol L-1 de NaCl utilizado como eletrólito suporte e degradação com o método eletroquímico foto-assistido em efluente do tanque de equalização (efluente sem tratamento biológico). / This study presents the electrochemical and photo-assisted electrochemical degradation of real textile industrial effluent at Dimensionally Stable Anodes (DSA). The effluent samples were collected directly from the mixing tank and from the final effluent discharge after biological treatment. The effluent samples were provided by the company Toalhas São Carlos situated in the city of São Carlos, São Paulo state. The degradation assays were performed in a filter-press cell with a commercial DSA electrode (nominal composition Ti/Ti0,7Ru0,3O2) under constant recirculation. In order to assess the best degradation parameters the influences of the type of electrolyte (NaCl and Na2SO4) was studied. NaCl concentrations (0.05 to 0.30 mol L-1), current density (10 a 120 mA cm-2) and pH (4, 7, 8, 9 and 12) were investigated. After defining the best parameters, new effluent samples were collected on alternate days to assess the influence of the effluent composition. Photo-assisted electrochemical tests were performed under the same conditions as the electrochemical tests in order to compare the two methods. Characterizations of the DSA materials were performed by cyclic voltammetry in the absence and presence of wastewater and light. During the 2 h electrolyses, samples were collected and analyzed by UV-vis spectroscopy, total organic carbon (TOC), chemical oxygen demand (COD) and conductivity. Analyses of the formation of degradation products were performed by phytotoxicity tests and AOX analysis. Greater toxicity was observed after 10 hours of electrolysis. Evaluation of residual chlorine and chloride complemented the studies. It was observed that degradation is more effective for the photo-assisted electrochemical method than electrochemical method. Also the addition of NaCl promotes degradation by in-situ generated oxidizing agents. Higher concentrations of NaCl and current densities increased color removal and COD. However in tests with different pH values, the best results were observed at lower pH. Considering all the results, the best parameters for degradation of real textile effluent were current density at 40 mA cm-2, pH 8 and 0.15 mol L-1 NaCl used as supporting electrolyte and degradation using the photo-assisted electrochemical method.
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Hydrologic and hydraulic processes in northern treatment peatlands and the significance for phosphorus and nitrogen removal

Ronkanen, A.-K. (Anna-Kaisa) 18 August 2009 (has links)
Abstract The understanding of flow processes is a key to evaluating treatment efficiency in constructed wetlands. This work focuses on the effects of flow paths on phosphorus (P) and nitrogen (N)retention in four treatment wetlands constructed on pristine peatlands in Finland. Particular attention was paid to water residence time, effective flow area and effective flow depth. Both an artificial tracer test and a new method based on the analysis of stable oxygen and hydrogen isotope distributions were employed. Tracer tests were used to calibrate steady-state flow models created using a groundwater modelling MODFLOW code. Furthermore, concentrations of P, Al and Fe in the peat and concentration of N in the surface water were measured. Surface water tracer distributions showed overland flow to be the dominant flow process and it was divided into a preferential flow area and dead zones. Also, active channel formation was observed during the years of the study (2002–2005). The results indicate that the hydraulic performance might deteriorate drastically within a short period of time. The active flow areas in the peatlands comprised only about 40–48% in summer, meaning that large areas with potential for nutrient removal were left unused. Flow simulations showed that a more optimal length of the distribution ditch will create a larger effective flow area and possibly could prevent channel formation. The peat P concentration was 1.8±3.9 mg g-1, and P was accumulated in the preferential flow area. The peat P concentration correlated positively with Al in the Ruka peatland treating wastewater. The results indicate that precipitation chemicals increase the P retention capacity of peatland substantially and maintain P retention at a stable level despite variable P loads. Furthermore, the results indicate that the accumulation of P to peat via adsorption and chemical precipitation is the major P removal process even after 10 years of loading. In Ruka, calculated N concentrations in surface water obtained with a first-order area model, together with regression analysis of the rate constant, were in good agreement with observed N concentrations. If a removal of 70% is to be achieved, the NH4-N loading to the peatland should be below 0.10 mg m2 d-1.
459

Application of Industrial Wastewater Effluent in Growth of Algae -- Effects of Heavy Metals on the Growth Rate, Fatty Acid and Lipid Content of Chlorella Sorokiniana and Scenedesmus Obliquus

Udeozor, Jude Onyeka, Udeozor, Jude Onyeka January 2017 (has links)
Growing interest in biofuel production from non-fossil fuel sources has resulted in several studies exploring different raw material sources as feedstock, including many algae species, for large-scale production of biofuel. Algae are promising feedstock due to advantages such as its short growth cycle, high biomass production, and lipid content. However, there are still challenges to overcome in order to use algae for commercial biofuel production. One of these challenges is the requirement for a large quantity of water and nutrients needed for growing large quantities of the algae. This work explores a potential solution to this challenge by studying the possibility of using industrial wastewater to grow algae for biofuel production. However, many industrial wastewaters, including effluents from semiconductor processing plants, are known to contain heavy metals that are toxic to humans and the environment. In this work, the effects of four of such metals ions, As(V), As(III), Ga(III), and In(III) on Chlorella sorokiniana and Scenedesmus obliquus strains were studied. In particular, the heavy metal toxicity on the strains, effects on its growth rate, biomass yield, lipid content and fatty acid methyl esters (FAME) were studied. Also, the effect of controlling pH on growth rate, biomass yield, lipid content, and FAME was studied for Chlorella sorokiniana in the presence of Ga(III). The results of the study confirmed the toxicity of these metals on both strains. However, Ga(III) and In(III) had the highest effect, while As(V) showed the least toxicity to the strains, with Chlorella sorokiniana withstanding concentrations of As(V) as high as 140mg/L. The heavy metals were slightly more toxic to Scenedesmus obliquus compared to Chlorella sorokiniana. In addition, the heavy metals reduced the growth rate of both strains. High percent changes in growth rate (more than 50%) were seen in cultures containing Ga(III) and In(III). Furthermore, concentration measurements with Inductively Coupled Plasma Optical Emission Spectrometer (ICP) before, during, and at the end of the growth period, showed that Scenedesmus obliquus adsorbed higher amounts of the heavy metals compared to Chlorella sorokiniana. Microalgae biosorption of heavy metals limits its end use, hence making Scenedesmus obliquus a less favorable option for this study, but may be a better choice for wastewater treatment applications. The effects of the four metals on the lipid content and FAME profile of Chlorella sorokiniana were studied. The result showed an increase in Chlorella sorokiniana lipid content in the presence of In(III), but a decrease in the presence of As(V) and As(III). The heavy metals had effects on the strain’s FAME compositions. The fatty acid composition included C16:0, C16:1, C16:2, C16:3, C18:0, C18:1, ω-6, C18:2, ω-6, and C18:3, ω-3 accounting for more than 97% of the total FAME composition. Furthermore, controlling the pH of the culture in the presence of Ga(III) at 6.5 led to higher adsorption of the heavy metal, increase in lipid content, but no significant change in FAME composition.
460

Investigating human pharmaceutical compounds present in municipal and hospital wastewaters and options for their removal

Al Qarni, Hamed M. January 2015 (has links)
Pharmaceutical compounds comprise a wide range of substances that are consumed in large quantities by modern societies and are generally released into local sewer networks through excretion. This research aimed to identify the factors affecting the removal efficiencies of these compounds in biological wastewater treatment plants (WWTPs) under different environmental conditions. Of the pharmaceutical compounds selected for this study, the highest influent concentrations measured in municipal wastewater treatment plants (MWWTPs) were for paracetamol, naproxen and bezafibrate (> 1 μg/L), followed by carbamazepine, atenolol, lidocaine, sulfamethoxazole and NACS (<1 μg/L). In hospital wastewater treatment plants (HWWTPs), the highest concentrations measured were for paracetamol and caffeine (> 10 μg/L), followed by ciprofloxacin and NACS (1–6 μg/L), and finally bezafibrate, carbamazepine, atenolol, lidocaine, clarithromycin and sulfamethoxazole (< 1μg/L). Antibiotic drugs were detected in HWWTPs, but rarely detected in MWWTPs. In general, the hospital wastewaters contained relatively higher levels of pharmaceuticals than municipal wastewaters. The removal efficiencies of the pharmaceutical compounds ranged widely. This was found to be related to characteristics and operational parameters of the individual WWTPs. The MWWTPs that utilized long aeration and biomass retention times (HRT,SRT), as evidenced by the occurrence of complete nitrification, were more efficient at removing paracetamol, naproxen, bezafibrate and atenolol, than the non-nitrifying plants with relatively shorter HRT and SRT. HWWTPs that operated under elevated ambient temperatures (> 26°C) achieved higher removal efficiencies (90%) for several compounds, including paracetamol, caffeine, sulfamethoxazole, ciprofloxacin, clarithromycin, NACS, atenolol, carbamazepine and lidocaine. In addition to the elevated ambient temperatures, elevated HRT and SRT and less dilution can lead to increased active biomass and can result in higher removal rates for the pharmaceutical compounds. Overall, the removal efficiencies of pharmaceuticals in WWTPs have been correlated to the type of treatment plant, the plants’ operational parameters (HRT, SRT), the climatic conditions (temperature and dilution effect of rainfall) and characteristics of the micropollutants (type and concentration). Aerobic and anaerobic batch biodegradation experiments were conducted to observe the removal of paracetamol, naproxen, ibuprofen and sulfamethoxazole at various SRTs. The biodegradation rates varied widely ranging from poor, to moderate, to high, depending on the SRT. Paracetamol was highly biodegradable under both aerobic and anaerobic conditions. Sulfamethoxazole was poorly biodegradable under aerobic conditions but highly biodegradable under anaerobic conditions. Relatively slow biodegradation rates were observed for ibuprofen and naproxen under both conditions; longer microbial adaptation periods for these two compounds were probably required. The most important factor affecting the removal of the compounds was the SRT. Therefore, the conclusion was drawn that combining anaerobic and aerobic systems with longer SRT and HRT could bring about significant reductions in the emissions of these contaminants into the environment via WWTPs; this is also a cost-effective option.

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