Ce travail a pour objectif de concevoir, de mettre en oeuvre et de modéliser, un petit pilote de traitement d'eau afin d'enchainer un grand nombre de cycles du procédé séquentiel AD-OX (ADsorption-OXydation) sur Charbon Actif (CA). On étudie l'évolution, au cours des cycles, de la capacité d'adsorption de différents charbons actifs (commerciaux et issus de la pyrolyse de boue de station d'épuration) sur différents effluents : modèle (phenol), colorant (tartrazine) et effluent industriel. L'étude des performances, en adsorption puis oxydation alternées, a precisé les caracteristiques fondamentales du procédé AD-OX. Après la première régénération, le charbon a perdu une grande partie de son pouvoir adsorbant (environ 80%). Ce résultat est d'ailleurs le principal point commun des divers essais (sur des charbons tres différents et sur des polluants également tres différents) : les charbons sont tres dégradés en tant qu'adsorbants et catalyseurs lors de la première oxydation, puis évoluent tres peu au cours des cycles suivants. De nombreuses mesures sur ces charbons neufs et usagés aident à mieux appréhender ce phénomène : surface BET, porosite, analyse thermogravimétrique, composition chimique globale (CHNSO, EDX, ICP/AES), fonctions de surface, pH au point de charge nulle… La désactivation de l'adsorption semble essentiellement résulter de la fixation sur le charbon d'oligomères difficilement oxydés et qui reduisent fortement la microporosité. Pour mieux interpréter ces experiences, des simulations numériques sont décrites dans cette étude. On a modélisé la premiere étape du procédé, le percage du phénol sur un charbon commercial neuf, qui montre le rôle prépondérant de la diffusion de surface, puis le percage sur CA usagé. Pour finir, on a développé un modèle de l'étape d'oxydation catalytique batch, une fois l'activité du charbon stabilisée, qui approche bien les données experimentales sans aucun ajustement de paramètre. / This study aims to design, implement and model a small fixed bed reactor so that to perform a large number of consecutive Adsorption- Xidation cycles over Activated Carbon (AC) for water treatment. The evolution of the adsorption capacity of various activated carbons (commercial and issued from sewage sludges) is investigated during the cycles treating different wastewaters: model (phenol), dye (tartrazine) and industrial effluent. The measurement of the adsorption and oxidation performances has allowed to precise the features of the AD-OX process. The activated carbon has lost most of its adsorption capacity (80%) after the first oxidative regeneration. This conclusion can be drawn for all experiments (with very different activated carbons and also different pollutants): the adsorptive and catalytic properties of the carbons are very much reduced during the first oxidation, but then remain rather stable over the subsequent cycles. Physico-chemical characterisation of fresh and aged activated carbons helps to better understand this phenomenon: BET surface area, porosity, thermogravimetry analysis, global chemical composition (CHNSO, EDX, ICP/AES), surface functional groups, pH at the point of zero charge ... The loss of adsorption capacity seems mainly to result from the chemisorption of oligomers, poorly oxidized and that significantly reduce the microporosity. To better interpret these experiments, numerical simulations are also described in this study. Breakthrough curves of phenol adsorption have been simulated first for fresh commercial activated carbon, showing the dominating role of surface diffusion, then for aged carbon. Finally, a model has been developed to describe the batch catalytic oxidation step when AC activity is stabilized, that fits the experimental data satisfactorily without any parameter adjustment

Activated carbon is an adsorbent that is commonly used for removing organic contaminants from air due to its abundant pores and large internal surface area. This thesis is concerned with the static adsorption capacity and adsorption kinetics for single and binary organic compounds on different types of activated carbon. These are important parameters for the design of filters and for the estimation of filter service life. Existing predictive models for adsorption capacity and kinetics are based on fundamental “hard” knowledge of adsorption mechanisms. These models have several drawbacks, especially in complex situations, and extensive experimental data are often needed as inputs. In this work we present a systematic approach that can contribute to the further development of predictive models, especially for complex situations. The approach is based on Multivariate Data Analysis (MVDA), which is ideally suited for the development of soft models without incorporating any assumptions about the mathematical form or fundamental physical principles involved. Adsorption capacity and adsorption kinetics depend on the properties of the carbon and the adsorbate as well as experimental conditions. Therefore, to make general statements regarding adsorption capacity and kinetics it is important for the resulting models to be representative of the conditions they will simulate. Accordingly, the first step in the investigations underlying this thesis was to select a minimum number of representative and chemically diverse organic compounds. The next steps were to study the dependence of the derived affinity coefficient, β, in the Dubinin-Radushkevich equation on properties of organic compounds and to establish a new, improved model. This new model demonstrates the importance of adding descriptors for the specific interaction with the carbon surface to the size and shape descriptors. The adsorption capacities of the same eight organic compounds at low relative pressures were correlated with compound properties. It was found that different compound properties are important in the various stages of adsorption, reflecting the fact that different mechanisms are involved. Ideal adsorbed solution theory (IAST) in combination with the Freundlich equation was developed to predict the adsorption capacities of binary organic compound mixtures. A new model was proposed for predicting the rate coefficient of the Wheeler-Jonas equation which is valid for breakthrough ratios up to 20%. Finally, it was shown that the Wheeler-Jonas equation can be adapted to describe the breakthrough curves of binary mixtures. New models were proposed for predicting its parameters, the adsorption rate coefficients, and the adsorption capacities for both components of the binary mixture. Thus, multivariate data analysis can not only be used to assist in the understanding of adsorption mechanisms, but also contribute to the development of predictive models of adsorption capacity and breakthrough time for single and binary organic compounds.

Stora mängder receptbelagda- och receptfria läkemedel brukas årligen. Farmaceutiska föreningar såsom exempelvis preventivmedel, antibiotikum och smärtstillande läkemedel når reningsverk via urin och fekalier. Traditionella reningsverk saknar förmågan att helt reducera dessa föreningar och de släpps ut via det utgående vattnet till en recipient där de kan medföra en negativ påverkan i miljön. Duvbackens reningsverk i Gävle har en traditionell uppbyggnad och det behandlade spillvattnet släpps ut i Inre Fjärden. Syftet med denna studie är att utifrån Duvbackens avloppsreningsverks förhållanden föreslå en rekommenderad kompletterande reningsmetod för att reducera läkemedelsrester ifrån spillvattnet.   För att kunna föreslå en kompletterande reningsmetod har en provtagning efter läkemedelssubstanser på det inkommande och det utgående spillvattnet genomförts i Duvbackens reningsverk. Detta för att se vilka substanser reningsverket reducerar och vilka som släpps ut i Inre Fjärden.  En litteraturstudie har genomförts där aktivt kol och ozons reduktionsförmåga av läkemedelsrester granskats, samt vart i reningsverket de bör implementeras. Kostnader av aktivt kol och ozon har ställs i förhållande till varandra genom en ekonomisk undersökning.   Duvbackens reningsverk är dimensionerat för 100 000 personekvivalenter och är beläget mellan stadsdelarna Brynäs och Bomhus i Gävle. Reningsverket använder sig av mekanisk, biologisk och vid behov kemisk rening. Resultaten från provtagningen visade att av de 22 läkemedelssubstanser vilka granskats reducerades sex substanser med mindre än 45 % och två substanser fick en förhöjd halt efter de passerat Duvbackens reningsverk.   Både ozon och aktivt kol har i tidigare pilotförsök visat god förmåga att reducera läkemedelssubstanser från avloppsvatten. Variation av reduktionsgrader har visats bero på kolförbrukning och dosering av ozon. En skillnad mellan de kompletterande reningsmetoderna är att aktivt kols reduktionsförmåga försämras med tiden medan ozon har en mer konstant reduktion av läkemedelssubstanser.   Ozon bör implementeras efter slutsedimenteringen följt av ett sandfilter för att reducera reaktiva biprodukter. Vid användning av aktivt kol bör reningsmetoden implementeras efter slutsedimenteringen, då det är av stor vikt att spillvattnet inte har för höga halter av suspenderade ämnen som mättar kolet. När aktivt kol och ozons kostnader jämförts under samma förhållanden har aktivt kol visats vara marginellt dyrare. Energikostnader utgör de stora kostnaderna för ozonrening medan kolförbrukningen visats utgöra den stora kostnaden för rening med aktivt kol. / Large amounts of prescription- and non-prescription pharmaceutical drugs are used annually. Pharmaceutical compounds such as contraception, antibiotics and analgesic drugs end up in sewage treatment plants via urine and feces. The traditional sewage treatment plant lacks the ability to completely reduce pharmaceutical compounds and they are emitted via efflux to a recipient, where they can have a negative impact on the environment. The sewage treatment plant Duvbacken in Gävle has a traditional structure and the treated effluent end up in Inre Fjärden. The purpose of this study is to recommend a complementary treatment method to reduce pharmaceutical compounds based on the sewage treatment plant Duvbacken’s circumstances.   In order to recommend a complementary treatment method samples of the incoming and outgoing efflux have been tested for pharmaceutical substances. The samples were taken to see what substances the sewage treatment plant reduces and what substances end up in Inre Fjärden. A literature review was conducted to examine activated carbon and ozone’s ability to reduce pharmaceutical compounds, it also researched where the treatment methods should be implemented. An economical investigation was done to show the costs for activated carbon and ozone in relation to each other.   The sewage treatment plant Duvbacken in Gävle is constructed for 100 000 persons and is located between the suburban areas Brynäs and Bomhus. The sewage treatment plant uses mechanical, biological and if necessary chemical treatment. The results from the samples of the 22 substances that were examined showed that six pharmaceuticals were reduced by less than 45 % and two substances had an increased concentration after treatment in the sewage treatment plant.   Both ozone and activated carbon have in previous studies shown good ability to reduce pharmaceutical substances from the municipal efflux. Variations in the ability to reduce pharmaceuticals depends on carbon consumption and ozone dosage. One difference between the complementary treatment methods are that activated carbons ability to reduce pharmaceuticals decreases with time, while ozone has a more constant reduction.   Ozone should be implemented after the traditional treatment followed by a sand filter to reduce reactive byproducts. Activated carbon should also be implemented after the traditional treatment due to an efflux with high content of suspended substances can saturate the carbon. When the costs of activated carbon and ozone are compared under the same circumstances it has been shown that activated carbon is marginally more expensive. The energy use represents the major costs for ozone treatment while carbon consumption has shown to be the major cost for activated carbon.

Doctor of Philosophy / Department of Biological and Agricultural Engineering / Ronaldo Maghirang / Emission of greenhouse gases (GHGs), including nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), from open beef cattle feedlots is becoming an environmental concern; however, scientific information on emissions and abatement measures for feedlots is limited. This research was conducted to quantify GHG emissions from feedlots and evaluate abatement measures for mitigating emissions. Specific objectives were to: (1) measure N2O emissions from the pens in a commercial cattle feedlot; (2) evaluate the effectiveness of surface amendments in mitigating GHG emissions from feedlot manure; (3) evaluate the effects of water application on GHG emissions from feedlot manure; and (4) compare the photo-acoustic infrared multi-gas analyzer (PIMA) and gas chromatograph (GC) in measuring concentrations of N2O and CO2 emitted from feedlot manure. Field measurements on a commercial beef cattle feedlot using static flux chambers combined with GC indicated that N2O emission fluxes varied significantly with pen surface condition. The moist/muddy surface had the largest median emission flux; the dry and compacted, dry and loose, and flooded surfaces had significantly lower median emission fluxes. Pen surface amendments (i.e., organic residues, biochar, and activated carbon) were applied on feedlot manure samples in glass containers and evaluated for their effectiveness in mitigating GHG emissions. Emission fluxes were measured with the PIMA. For dry manure, all amendments showed significant reduction in N2O and CO2 emission fluxes compared with the control (i.e., no amendment). For moist manure, biochar significantly reduced GHG emissions at days 10 and 15 after application; the other amendments had limited effects on GHG emissions. The effect of water application on GHG emissions from feedlot manure was evaluated. Manure samples (with and without water application) were placed in glass containers and analyzed for GHG emission using a PIMA. For the dry manure, GHG emissions were negligible. Application of water on the manure samples resulted in short-term peaks of GHG emissions a few minutes after water application. Comparison of the GC and PIMA showed that they were significantly correlated but differed in measured concentrations of N2O and CO2. The PIMA showed generally lower N2O concentrations and higher CO2 concentrations than the GC.

M. Tech., (Chemical Engineering, Department of Chemical Engineering, Faculty of Engineering and Technology Vaal University of Technology| / The methods used to remove potassium sulphate (K2S04) and other impurities contained within Karbochem finishing plant effluent were investigated. Reverse osmosis was explored for this application. The study was conducted in two steps. The first step focuses mainly on the effluent treatment using BW30 flatsheet as well as BW30-2540 spiral-wound reverse osmosis membranes for the rejection of potassium and sulphate ions. The membranes were supplied by Filmtec. The second step reveals the possible use of potassium sulphate obtained from the brine stream in the fertiliser and fertigation industry by a literature search. Reverse osmosis study was conducted on a laboratory scale unit using flat sheet membranes and also on a pilot plant scale using spiral wound membrane modules. The tests were conducted at a feed pressure of 20 bar(g) with the membrane rejections being 98% and 99.1% on flat sheet membrane, and 96.9% and 99.4% on spiral wound membrane for potassium and sulphates respectively. The results show that both membranes have completely desalinated. Significant reduction in the concentrations of all problematic quality parameters, especially of potassium and the sulphate ions was noted. Granular activated carbon (GAC) bed treatment was recommended for pretreatment of the effluent prior to exposure of the membrane to avoid organic fouling of the membrane. GAC treatment was tested to illustrate its effectiveness to adsorb the COD's. / NRF

This diploma thesis deals with the study of adsorption of low-molecular components of organic substances produced by phytoplankton - AOM (Algal Organic Matter) on AC (Activated Carbon) during drinking water treatment. For the experimental purpose in this thesis, there were used selected amino acids as low molecular substances of AOM that are difficult to remove by conventional water treatment process by coagulation. As adsorbent, there was used a detailed characterized of granulated activated carbon (GAC) - Filtrasorb TL 830 (FTL830) which is intended directly for the purpose of water treatment. There were realizing the equilibrium batch adsorption experiments with three different model amino acids - arginine (Arg), phenylalanine (Phe) and aspartic acid (Asp). There was investigated the efficiency of removing amino acid depending on the solution temperature and pH. Results of the adsorption experiments have shown that the temperature affects the adsorption efficiency. Adsorption is essentially described as an exothermic process but the adsorption of Arg and Phe from an aqueous solution to GAC occurs more efficiently at higher temperatures. It means that the adsorption is the endothermic process. In the case of Arg adsorption, the temperature was found to influence adsorption efficiency less than...

A presença de resíduos de fármacos em águas superficiais e de abastecimento público tem preocupado a comunidade científica devido principalmente à sua persistência na água e aos efeitos adversos causados à comunidade aquática e aos possíveis riscos à saúde humana. Dentre os fármacos comumente identificados em águas de abastecimento público, encontram-se os anti-inflamatórios, como o diclofenaco (DCF), um dos fármacos mais consumidos no Brasil e no mundo. Nesse contexto, o presente trabalho, teve como objetivo principal estudar a eficiência das etapas de tratamento de água em ciclo completo (coagulação, floculação, sedimentação, filtração em areia e desinfecção com cloro) com e sem pré-oxidação com cloro e com dióxido de cloro e adsorção em carvão ativado granular (CAG) na remoção de DCF. Também foram determinados os trialometanos (THM) e identificados os principais subprodutos do DCF formados na oxidação com cloro e dióxido de cloro. Para a determinação do DCF nas amostras de água antes e após as etapas de tratamento de água foram desenvolvidos e validados métodos analíticos de extração em fase sólida (SPE) e cromatográfico por cromatografia líquida de alta eficiência (HPLC) com detecção no ultravioleta (UV). A validação do método foi feita de acordo com a resolução n&ordm; 899 de 2003 da Agência Nacional de Vigilância Sanitária (ANVISA), considerando os requisitos para métodos bioanalíticos. Os procedimentos analíticos empregados foram efetivos e confiáveis para a identificação e quantificação do DCF nas amostras de água antes e após os processos de tratamento de água. Os ensaios de tratamento de água foram feitos em equipamento de reatores estáticos (jarteste) e filtros de escala laboratorial empregando-se água de poço artesiano não clorada preparada com substâncias húmicas aquáticas (SHA) para conferir cor verdadeira de 20 uH, caulinita para conferir turbidez de 70 uT e fortificada com 1 mg L-1 de DCF. Os resultados indicaram que as etapas de coagulação com sulfato de alumínio, floculação, sedimentação e filtração em areia não removeram o DCF. Nas etapas de préoxidação com cloro e dióxido de cloro e de pós-cloração houve remoção parcial do DCF, porém verificou-se a formação de subprodutos provenientes da oxidação do DCF. Dentre os THM, foi quantificado apenas o clorofórmio na etapa de pré-oxidação com cloro. Em geral, os resultados indicaram que o dióxido de cloro foi mais eficiente na redução do DCF e formou menos subprodutos. Entretanto, o tratamento em ciclo completo seguido da adsorção em CAG foi eficiente na remoção de DCF, com remoção maior que 99,7%. Os subprodutos formados na oxidação com cloro e dióxido identificados por cromatografia líquida acoplada a espectrometria de massas em série (LC-MS/MS) consistiram na descaboxilação/hidroxilação e substituição aromática de átomos de hidrogênio por cloro. Os subprodutos identificados na oxidação com cloro apresentaram as seguintes fórmulas moleculares: C14H11</subCl2NO3, C13H10Cl3N e C14H10Cl3NO2. Com o dióxido de cloro foi identificado o subproduto de fórmula molecular igual a C14H11Cl2NO3. / The presence of pharmaceutical residues in surface waters and in drinking water supply has concerned the scientific community, mainly in which regards their persistence in water, adverse effects on the aquatic community and possible risks to human health. Antiinflammatory drugs, as diclofenac (DCF), are among those drugs commonly identified in drinking water supply. In this context, the main objective of this study was to assess the efficiency of the different stages of the conventional drinking water treatment (coagulation, flocculation, sedimentation, sand filtration and chlorine disinfection) with and without preoxidation with chlorine and chlorine dioxide and adsorption on granular activated carbon (GAC) in the removal of DCF. The trihalomethanes (THMs) were also determined and the main by-products of DCF formed by oxidation with chlorine dioxide and chlorine were identified. For the DCF determination in water samples before and after water treatment stages analytical methods of solid phase extraction (SPE) and chromatographic method by high performance liquid chromatography (HPLC) with detection in the ultraviolet (UV) were developed and validated. The method validation was based on Resolution n&ordm; 899 of the 2003 of the Brazilian National Health Surveillance Agency (ANVISA), considering the requirements for bioanalytical methods. The analytical procedures used were effective and reliable for the identification and quantification of DCF in the water samples before and after the water treatment stages. The water treatment tests were carried out in jar test equipment and filters on laboratory scale employing non chlorinated water of artesian well prepared with aquatic humic substances (AHS) to yield 20 uH true color, kaolin turbidity of 70 NTU and DCF concentration of 1 mg L-1. The results indicated that the stages of coagulation with aluminum sulphate, flocculation, sedimentation and filtration sand did not remove DCF. In the stages of pre-oxidation with chlorine and chlorine dioxide and chlorine disinfection the DCF was partially removed, however by-products were formed from the DCF oxidation. Among the THMs, only chloroform was quantified in the pre-oxidation with chlorine. In general, the results showed that chlorine dioxide was more effective to reduce the DCF and fewer by-products were formed. Nevertheless, the complete cycle treatment followed by GAC adsorption was effective to remove DCF (&gt; 99.7%. removal). The by-products of the oxidation of DCF with chlorine and chlorine dioxide identified by liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) consisted in the descaboxylation/hydroxylation and aromatic substitution of hydrogen atoms by chlorine. The compounds identified in the oxidation with chlorine showed the following molecular formulas: C14H11</subCl2NO3, C13H10Cl3N e C14H10Cl3NO2. The by-product identified using chlorine dioxide was C14H11Cl2NO3.

A cianobactéria Arthrospira (Spirulina) platensis, é um dos micro-organismos fotossintetizantes mais estudados e cultivados, e atualmente tem sido utilizado para a produção de biomassa, com elevado conteúdo de proteínas, vitaminas, minerais, aminoácidos essenciais, ácidos graxos poli-insaturados e pigmentos, com potencial uso como complemento alimentar para humanos, bem como em alimentação de animais. No entanto, o cultivo de micro-organismos fotossintetizantes tem uma demanda hídrica bastante alta. Dessa forma, é importante a realização de trabalhos que avaliem a possibilidade de reuso de meio de cultivo de Arthrospira, que, além de reduzir os custos com nutrientes, contemplam o aspecto ambiental, evitando salinização do solo e eutrofização de corpos hídricos. Este trabalho avaliou a reutilização de meios do cultivo de Arthrospira (Spirulina) platensis tratados com carvão ativado em pó e diferentes agentes coagulantes. Os efluentes foram obtidos dos cultivos de A. platensis com nitrato de sódio como fonte de nitrogênio em processo descontínuo, em minitanques. Os efluentes passaram por tratamentos físico-químicos com diferentes concentrações de carvão ativado em pó (30, 40 e 50 mg.L-1) e cloreto férrico (6, 10 e 14 mg.L-1) ou sulfato férrico (15, 25 e 35 mg.L-1) para serem reaproveitados em cultivos desse micro-organismo. O reuso de meio no cultivo de A. platensis mostrou resultados aceitáveis, observando-se que o crescimento desta cianobactéria foi satisfatório, com obtenção de concentração celular máxima (Xm) obtida de 1093 mg.L-1 em frasco Erlenmeyer, correspondente ao ensaio com meio tratado com 30 mg.L-1 de carvão ativado em pó (CAP) e 6 mg.L-1 de cloreto férrico. Esses resultados de crescimento celular foram da mesma ordem de grandeza que os resultados de Xm obtidos com meio novo e maiores que aqueles oriundos de crescimentos em meios tratados com sulfato férrico como agente coagulante, cujos valores de concentração celulares máximas não excederam 806 mg.L-1. Os cultivos em meios provenientes de tratamento com cloreto férrico não alteraram a composição da biomassa, chegando a valores de teor protéico da ordem de 47%. Conclui-se que o reuso de meio pode ser viável para a produção de biomassa de A. platensis, reduzindo o custo de produção pelo reuso dos nutrientes. / The cyanobacterium Arthrospira (Spirulina) platensis, one of the most studied and cultivated photosynthetic microorganisms and, currently has been used for biomass production of biomass, with high contents of protein, vitamins, minerals, amino acids, polyunsaturated fatty acids, and pigments, with potential use as a dietary supplement for human food supplement and animal feed. However, the cultivation of photosynthetic microorganisms have a very high water demand. Thus, is important to carry out studies evaluating the possibility of reuse of Arthrospira culture medium, which, in addition to reducing the costs of nutrients, include the environmental aspect, preventing soil salinization and eutrophication of water bodies. This work has evaluated the reuse of effluent medium from Arthrospira (Spirulina) platensis cultivation treated with powdered activated carbon and different coagulants. The effluent, obtained from A. platensis batch cultivation in bench-scale open ponds, using sodium nitrate as a nitrogen source. The effluent went through physico-chemical treatments employing different concentrations of powdered activated carbon (30, 40, and 50 mg.L-1) and ferric chloride (6, 10, and 14 mg.L-1) or ferric sulphate (15, 25, and 35 mg.L-1) for them to be reused in cultured microorganism. The reuse through the cultivation of A. platensis showed acceptable results, observing that the growth of this cyanobacterium was satisfactory, obtaining maximum cell concentration (Xm) obtained 1093 mg.L-1 in Erlenmeyer flask, corresponding to the assay medium treated with 30 mg.L-1 of powdered activated carbon (PAC) and 6 mg.L-1 ferric chloride. The results of cell growth were the same order of magnitude as the results of Xm obtained with new culture medium and larger than those from growth in media treated with ferric sulfate as a coagulant agent, whose maximum values of cell concentration did not exceed 806 mg.L-1. The cultures in media from treatment with ferric chloride did not alter the composition of the biomass, reaching values of protein content of around 47%. It is concluded that the reuse of cultures medium may be feasible to produce biomass of A. platensis, reducing the production cost by recycling of nutrients.

O objetivo deste trabalho foi avaliar o desempenho da combinação dos processos de interozonização e sistemas pós-filtros adsorvedores na remoção de compostos orgânicos precursores e na formação de subprodutos da desinfecção, em particular os trialometanos (THM). Os ensaios foram desenvolvidos com a água filtrada proveniente da estação de tratamento de água do Alto da Boa Vista, localizada no município de São Paulo, tipo convencional, com água bruta oriunda de reservatório com elevado estado de eutrofização. O aparato experimental é constituído de um sistema de ozonização com quatro colunas em série e tempo de detenção hidráulica total de 16 minutos; e, por um sistema de quatro pós-filtros adsorvedores com diferentes tipos de carvão ativado granular, filtros F1 e F3 dotados de carvão mineral (CAG1, betuminoso) e filtros F2 e F4 compostos por carvão vegetal (CAG2, casca de coco) sendo todos operados em paralelo com valores de Tempo de Contato de Leito Vazio (TCLV) entre 15 e 20 minutos. Duas colunas receberam como afluente água filtrada pré-ozonizada (F1 e F2) e as demais colunas apenas água filtrada (F3 e F4). Os resultados indicaram que a ozonização não alterou de forma significativa os parâmetros utilizados para avaliação dos precursores, COT e UV-254 nm, e nem o THM. Inicialmente, os resultados de remoção de COT permaneceram elevados, próximos de 80% caracterizando a saturação dos leitos em torno de 240 dias para os filtros F1 e F3 (CAG1) e apenas 30 dias, com eficiências baixas para os filtros F2 e F4 (CAG2). Para THM a saturação foi próxima de 65 dias para ambos os carvões e as eficiências iniciais foram de 90% e 75%, para os filtros com CAG1 e CAG2, respectivamente. Com todos os leitos saturados, os resultados ainda indicaram boa remoção de compostos causadores de gosto e odor. Neste trabalho, os sistemas de pós-filtros adsorvedores de CAG foram efetivos para o controle das substâncias precursoras e a redução da formação de THMs, com melhores resultados para o carvão mineral CAG1 (betuminoso) independentemente do sistema de interozonização. / The main purpose of this work was to evaluate the performance of a combination of processes - inter-ozonization and post-filter GAC adsorbers systems, on the control of organic precursors and disinfection byproducts, especially trihalomethanes (THM). The experience was conducted with filtered water produced at Alto da Boa Vista conventional WTP, located at São Paulo city, where raw water comes from a high eutrofic lake. The experimental setup consists of an ozonation system with four column shaped contactors arranged in series with 16 minutes total hydraulic detention time; and, a system of four pilot scale adsorbers with different types of granular activated carbon (GAC) media, F1 and F3 filters with mineral GAC media (GAC1, bituminous) and F2 and F4 filters with vegetal GAC media (GAC2, coconut shell), all operated in parallel with empty bed contact time (EBCT) between 15 and 20 minutes. Two columns were fed with filtered and pre-ozonated water (F1 and F2) and the other two were fed with filtered water only (F3 and F4). It was observed that ozonation did not affect significantly results of precursors parameters, TOC and UV-254, and neither THM. Initially, TOC removal remained high, near 80% delineating the bed saturation around 240 days to F1 and F3 filters (GAC1) and only 30 days with low efficiency for filters F2 and F4 (GAC2). The THM bed saturation time was nearly 65 days for both media and initial efficiencies were 90% and 75% to GAC1 and GAC2, respectively. With all beds saturated, still there was a good taste and odor producing substances removal. In this work, the systems of GAC adsorbents post-filters were effective for the control of precursors and to reduce the formation of THM\'s, with better results for the CAG1 (bituminous) regardless of the use of inter-ozonization.

A crescente degradação da qualidade dos mananciais que servem os sistemas públicos de abastecimento de água potável faz com que se busquem novas técnicas para remoção de compostos indesejáveis. Os fatores climáticos que predominam no Brasil favorecem o desenvolvimento, em ambientes eutrofizados, de microrganismos conhecidos como cianobactérias que podem ser potencialmente produtores de toxinas. Este trabalho estudou a eficiência de remoção de microcistinas em um sistema que associa coagulação, floculação, flotação por ar dissolvido, adsorção em carvão ativado e filtração, com o intuito de remover a maior quantidade possível de microcistina para minimizar as dosagens de carvão ativado necessárias à remoção de concentrações de microcistinas - hepatotoxinas produzidas por cianobactérias - uma vez que, em uma estação real, uma menor dosagem de carvão ativado representa menores custos. Até o momento, o estado da arte permite afirmar que a aplicação de carvão ativado constitui a etapa final de um sistema de tratamento usualmente utilizado para a eficiente remoção de toxinas. Em escala de laboratório, foram feitos ensaios em equipamentos com alimentação por batelada: jarteste e flotateste. Após a preparação da água de estudo, uma amostra foi submetida à mistura rápida em um equipamento de jarteste, com aplicação de produtos químicos para atingir valores desejados de pH e, em outros ensaios, também foi adicionado o carvão ativado em pó - CAP. Após a coagulação, a amostra ensaiada era transferida para o equipamento de flotateste para a floculação e posterior flotação por ar dissolvido e, em alguns casos, submetido à filtração em papel Whatman 40. Observou-se que o uso dos parâmetros de cor e turbidez não foram suficientes para garantir a também remoção de microcistina. No sistema proposto, a aplicação de CAP antes da mistura rápida apresentou melhor desempenho na remoção de microcistina do que quando aplicado posteriormente a esta etapa; foi necessário dosagem de 60 mg/L de CAP, aplicado a 1,5 hora antes da mistura rápida para que a concentração de microcistina ficasse inferior a 1 &#956g/L. O sistema que associa coagulação, floculação, flotação por ar dissolvido, adsorção em carvão ativado e filtração mostrou ser capaz de remover microcistina a níveis inferiores a 1 &#956g/L, conforme estabelecido na Portaria 518/04 do Ministério da Saúde. / The growing quality degradation of the water sources serving the public distribution of drinking water results in the search of new techniques for the removal of undesirable compounds. The brazilian climate factors are in favor of the development of eutrophic environments, and of microorganisms known as cyanobacteria that are potential sources of toxins. This work studied the microcystin removal efficiency in a system that associates, coagulation, flocculation, dissolved air flotation, adsorption in activated carbon and filtration, with the scope to remote the maximum possible quantity of toxins in order to minimize the activated carbon dosage need to the removal of microcystin concentration - hepatotoxins produced by cyanobacteria - taking into accounts that in a real plant, the less the activated carbon, the less the operation costs. So far, the state of art permits the affirmation that the activated carbon characterizes the final step of a treatment system usually used for the efficient removal of toxins. In the laboratory scale tests were done in batch equipments: jartest and flotatest. After the preparation of the water in study one sample was submitted to a quick mixture in a jartest, with the application of chemical products to reach the desired pH levels, and in other assays powder activated carbon PAC was also added. After the coagulation, the tried sample was transferred to the flotatest equipment to achieve flotation and posterior dissolved air flotation, and in some cases, submitted to filtration in Whatman 40. It could be observed that the use of color and turbidity parameters were not sufficient to guarantee the microcystin removal. In the proposed system, the PAC application before the quick mixture presented better performance in the removal of microcystins than the posterior application to this step; a dosage of 60 mg/L of PAC was necessary when applied 1,5 hour before the quick mixture for the microcystin concentration be as low as 1 &#956g/L. The system which associates coagulation, flocculation, dissolved air flotation, activated carbon adsorption and filtration, exhibits the ability of microcystin removal to levels below 1 &#956g/L as is established in Portaria 518 - 23/03/05 - Ministério da Saúde - Brazil.