CAPES; / As características do material suportem afetam diretamente a eficiência de um reator, pois o número e os tipos de células que aderem em cada meio suporte podem variar de um material para outro. A partir do desenvolvimento dos primeiros filtros anaeróbios um ponto crucial identificado pela comunidade científica foi a busca por materiais suportes que melhor se adequassem, ou seja, inertes à biomassa imobilizada, proporcionando bons resultados, facilidade operacional e economicamente viáveis. Uma alternativa é a utilização de materiais alternativos para preenchimento dos filtros, com estrutura resistente, biológica e quimicamente inerte, leveza, maior área específica e porosidade elevada, com possibilidade de colonização acelerada dos microrganismos e custos reduzidos. Neste trabalho foram avaliadas a estabilidade e o comportamento hidrodinâmico de três filtros anaeróbios de fluxo ascendente, operados de modo contínuo, preenchidos com diferentes meios suportes para imobilização da biomassa, sendo carvão vegetal, cerâmica de argila e borracha de pneu, no tratamento de água residuária sintética à base de glicose como fonte de carbono. Os filtros, em escala de bancada (1,3 L), foram operados com TDH de 8 h e 4 h em duas etapas e mantidos a temperatura ambiente. A caracterização físico-química dos materiais foi realizada com determinação dos parâmetros pH, massa específica aparente, densidade, teor de umidade, material volátil, teor de cinzas, número de iodo, porosidade, granulometria, análise da morfologia, área superficial, volume e tamanho dos poros. O comportamento dos filtros foi avaliado por meio da determinação dos parâmetros de pH, temperatura do líquido, alcalinidade total e a bicarbonato, ácidos voláteis e DQO nas amostras do afluente e do efluente. Além disso, foram realizados ensaios de estímulo-resposta tipo pulso com eosina Y como traçador para avaliar o comportamento hidrodinâmico do reator. O desempenho dos filtros em termos de pH, alcalinidade total e a bicarbonato e ácidos voláteis foi estável nas duas etapas de operação. Os valores obtidos em termos de DQO nas amostras do afluente e efluente dos filtros com carvão ativado foram: - Etapa I: 457 e 38 mg.L-1 (94% de remoção); - Etapa II: 291 e 79 mg.L-1 (79% de remoção); com cerâmica de argila foram: - Etapa I: 457 e 81 mg.L-1 (81% de remoção); - Etapa II:: 291 0 e 129 mg.L-1 (60% de remoção); e com borracha de pneu foram: - Etapa I: 457 e 58 mg.L-1 (88% de remoção); - Etapa II: 291 e 117 mg.L-1 (63% de remoção). O teste estatístico de Kruskal-Wallis. e o pósteste de Dunn confirmaram os dados experimentais e provaram que para maior parte dos parâmetros há diferença nos valores entre os filtros e entre as duas etapas. Sendo as diferenças obtidas entre os filtro devido as características distintas de cada material, e as diferenças entre as etapas ocorrem pelo aumento da carga hidráulica, pois o aumento da velocidade ascensional diminui o tempo de retenção celular e assim o grau de estabilidade. Contudo, meio suporte permitem aos filtros mais estabilidade e boas eficiências de degradação. / The characteristics of material directly affect the reactor efficiency, because the number and the types of cells what adhere in each material support can be totally different from material to another. From the development of the first anaerobic filters an important point identified by the scientific community was the search for materials that support better fitted, i.e. biomass immobilized inert, providing good results, operating ease and economically viable. An alternative is to use alternative materials for filling of filters, with sturdy structure, biologically and chemically inert, lightness, bigger specific area and high porosity, with possibility of rapid colonization of microorganisms and reduced costs. In this thesis it was evaluated the stability and the hydrodynamic behavior of three upflow anaerobic filter, operated in continuous mode, filled with different material support from immobilization to biomass being active carbon, clay ceramic and tire rubber in the synthetic wastewater treatment on based glucose as carbon source. The filter, in bench scale (1,3 L), was operated HRT to 8 hours and 4 hours in two steps Kept at ambient temperature. The physicochemical characterization of the materials was carried out with determination of parameters pH, bulk density apparent, density, moisture content, volatile material, ash content, iodine number, porosity, particle size, morphology analysis, surface area, volume and size pores. The behavior of the filters was evaluated by determining the parameters pH, liquid temperature, total and bicarbonate alkalinity, volatile acids and COD in samples of influent and effluent. Further, tests were performed stimulus-response type pulse with eosin Y, to evaluate the hydrodynamic regime of the reactor.The values obtained in terms of COD in samples of influent and effluent filters with activated carbon were: - Stage I: 457 and 38 mg.L-1 (94% of removal); - Stage II: 291 and 79 mg.L-1 (79% of removal), with clay ceramic were: - Stage I: 457 e 81 mg.L-1 (81% of removal); - Stage II: 291 and 129 mg.L-1 (60% of removal) and tire rubber were: - Stage I: 457 and 58 mg.L-1 (88% of removal); - Stage II: 291 and 117 mg.L-1 (63% of removal). The Kruskal-Wallis Statistical test and the Dun post-test confirmed the experimental data and proved from most part of parameters there is difference on values between the filters and between the two steps. Being the differences obtained between the filters due to distinct characteristics of each material, and the differences between the steps happened by hydraulic charging increased, because the ascending speed increased reduce the retention cellular therefore the degree of stability. However, material support allow the filters more stability and good degradation efficiencies.

The hydrometallurgical refining of platinum group metals results in large volumes of liquid waste that requires suitable treatment before any disposal can be contemplated. The wastewater streams are characterized by extremes of pH, high inorganic ion content (such as chloride), significant residual metal loads and small amounts of entrained organic compounds. Historically these effluents were housed in evaporation reservoirs, however lack of space and growing water demands have led Anglo Platinum to consider treatment of these effluents. The aim of this study was to investigate whether biological wastewater treatment could produce water suitable for onsite reuse. Bench-scale activated sludge and anaerobic digestion for co-treatment of an acidic refinery waste stream with domestic wastewater were used to give preliminary data. Activated sludge showed better water treatment at lab scale in terms of removal efficiencies of ammonia (approximately 25%, cf. 20% in anaerobic digestion) and COD (70% cf. 43% in digestion) and greater robustness when biomass health was compared. Activated sludge was consequently selected for a pilot plant trial. The pilot plant was operated on-site and performed comparably with the bench-scale system, however challenges in the clarifier design led to losses of biomass and poor effluent quality (suspended solids washout). The pilot plant was unable to alter the pH of the feed, but a two week maturation period resulted in the pH increasing from 5.3 to 7.0. Tests on algal treatment as an alternative or follow-on unit operation to activated sludge showed it not to be a viable process. The activated sludge effluent was assessed for onsite reuse in flotation and it was found that there was no significant difference between its flotation performance and that of the process water currently used, indicating the effluent generated by the biological treatment system can be used successfully for flotation. Flotation is the method whereby minerals refining operations recover minerals of interest from ore through the addition of chemicals and aeration of the ore slurry. Target minerals adhere to the bubbles and can be removed from the process.

MENVSC / Department of Hydrology and Water Resources / Sewage sludge (biosolids) from wastewater treatment plants (WWTPs) has been widely used as a soil improver in Europe, United States of America and some developing countries including South Africa. It has its benefits for farmers as a good source of organic matter and minerals, however, sludge after treatment still contains pathogenic organisms, heavy metals and persistent organic pollutants (POPs). The POP and heavy metal contaminants that accumulate in sludge may transfer through the food chain and cause adverse effects on human beings. In this study, a field experiment was carried out on farmland fertilized with sewage sludge from a wastewater treatment plant (WWTP) that vasically receives domestic wastewater and storm water. Vegetable spinach (Spinacia oleracea) was used for this study and was planted on a farmland under controlled conditions. Ten ridges each of dimensions 20 m × 0.3 m was made and dry sludge weights of 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 kg were applied as manure on each of the ridges, respectively. Representative samples of sludge and soil were taken for analysis of heavy metals and POPs. At maturity, in twelve weeks, the root and leave samples of the vegetable were taken from all the ridges including the control. The soil, sludge, and vegetable samples were analyzed for total heavy metal content (Cd, Cr, Cu, Ni, Pb, Co, Zn, Al, Fe, Mn), speciated heavy metal content and POP (PAH, PCB). Soil and sludge samples were also analyzed for total organic content, pH, cation exchange capacity (CEC), conductivity and alkalinity. The analysis for total heavy metals and speciated heavy metal content was carried out using inductively coupled plasma optical emission spectrophotometer (ICP-OES), and CEC analysis was carried out using atomic absorption spectrophotometer (AAS). A two-dimensional gas chromatograph with time of flight mass spectrometry detector (GC X GC TOFMS) was used for POP measurements. pH measurement was made using a pH meter and conductivity measurement using a conductivity meter. Alkalinity and total organic content analysis was performed using titrimetric apparatus. The highest total heavy metal concentration of 378.9 mg / kg was recorded in Fe metal in soil and Leaf sample while the lowest total metal concentration of 0.0003 mg / kg was in Cu metal in root sample. The highest heavy metal concentration of 1002 mg / kg in speciated forms was in Mn metal in F1 fraction and the lowest of 0.0004 mg / kg was in Cd metal in F5 fraction. PAHs were only found in soil samples and their concentrations ranged from 2.53 mg / kg to 146.5 mg / kg. There were no PCB detected in all the samples analysed. The results indicated that the trace metals concentrations found in the exchangeable fraction were higher than those observed in any of the preceding extractions except in the case of Cd, Cr, Fe and Pb where Fe-Mn oxide and organic matter fractions predominated and were closely followed by exchangeable fraction.

Thesis (PhD)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: Please see fulltext for abstract / AFRIKAANSE OPSOMMING: Sien asb volteks vir opsomming

The objective of this study was to investigate the feasibility of the application of low cost high capacity inorganic ion exchange material, synthesized form collected fly ash and acid mine drainage solid residues, for the decontamination of secondary co-disposal process waters, with emphasis on investigating the processes governing the solid/solution interface.

The primary objective of this study was to evaluate the rates of nitrate removal for a nitrate containing, low organic carbon wastewater interacting with four different carbon-containing solid substrates (alder woodchips, corn silage, manure and woodchip biochar). Batch systems were tested for nitrate removal, and systems with a combination of three carbon substrates (75% woodchips, 12.5% silage, and 12.5% manure or woodchip biochar by mass) produced average nitrate removal rates of 571 and 275 mg-N L⁻¹ D⁻¹, and systems containing the carbon substrates individually produced rates between 11.4 - 3.3 mg-N L⁻¹ D⁻¹. Silage proved to be the dominant carbon substrate providing high quantities of organic carbon to fuel denitrification. With the introduction of semi-continuous flow, all systems had nitrate removal rates that converged to 13.3 – 6.4 mg-N L⁻¹ D⁻¹, which is approximately two orders of magnitude smaller than the rates of the mixture systems in the batch experiment. Silage appeared to be removed from of the systems with liquid exchange potentially causing the rate decreases. Columns filled with various volume fractions of woodchips (100%, 25%, 12.5%, and 0%) produced nitrate removal rates between 30.8 – 2.4 mg-N L⁻¹ D⁻¹ at a 24 hour and 12 hour hydraulic residence time (HRT). Greater nitrate removal was achieved with higher HRTs and larger fractions of woodchips (the 100% woodchip system at a 24 hour HRT produced the fastest nitrate removal rate of 30.8 mg-N L⁻¹ D⁻¹). When rates were normalized to the amount of woodchips in each column, higher efficiency was found in lower woodchip fraction systems (the 12.5% woodchip column produced the highest normalized nitrate removal rate of 56 mg-N L⁻¹ D⁻¹ L[subscript woodchips]⁻¹). Woodchips proved to be best suited as a long term carbon substrate for nitrate removal in a system containing a nitrate concentrated, low organic carbon wastewater. However, large amounts of woodchips were necessary to achieve nitrate removal greater than 50%. A 41 acre hypothetical wetland with a 3.3 day HRT and a nitrate influent concentration of 45 mg-N L⁻¹ would require 30,000 yd³ of woodchips to achieve 68% nitrate removal based on the values obtained in the bench scale column experiment. / Graduation date: 2012

Els Sistemes d'Aiguamolls Construïts (SAC) de Flux Subsuperficial Horitzontal (FSH) és una tecnologia apropiada pel sanejament d'aigües residuals procedents de nuclis de població petits. No obstant els SAC de FSH són considerats una tecnologia natural, l'operació i manteniment d'aquestes depuradores és crucial per a garantir el seu correcte funcionament. Aquestes necessitats d'operació i manteniment varien entre depuradores segons (1) les característiques de la comunitat, (2) la configuració de la depuradora i el disseny del SAC de FSH i (3) les característiques del medi receptor. En aquest sentit, en aquesta tesi es presenta el desenvolupament d'un Sistema d'Ajuda a la Decisió (SAD) per a la definició de protocols d'operació i manteniment per a SAC de FSH tenint en compte els factors que causen variabilitat entre aquest tipus de depuradores (1, 2 i 3). / Horizontal Subsurface Constructed Wetlands (HSCW) is an appropriate technology to treat wastewater coming from small communities. Despite HSCW is considered a natural technology, operation and maintenance are crucial to guarantee their performance. These necessities vary according to (1) the characteristics of the community, (2) the wastewater treatment plant configuration and the HSCW design and (3) the characteristics of the receiving media. In this sense, the this thesis presents the development of an Environmental Decision Support System (EDSS) to asses the definition of operation and maintenance protocols for HSCW taking into account the aspects that cause variability among these facilities (1, 2 and 3).

Separation of dissolved metals from aqueous solutions using liquid membrane technology is highly advantageous owing to the degree of separation achieved, efficiency and application potential. In the present investigation four types of liquid membranes - bulk liquid membrane (BLM), emulsion liquid membrane (ELM), electrostatic pseudo liquid membrane (ESPLIM) and unified liquid membrane (ULM) have been extensively studied, for their application in extraction and concentration of dissolved metals from effluents. Experiments were conducted with various metal systems to optimize both system and process conditions and to find out the effect of various parameters on the performance of the process. Different mass transport models were proposed for each type, taking diffusional and kinetic resistances into account. Models were extended for simultaneous extraction systems and were verified by different metal-carrier experiments. Good agreement was found between the concentration profiles obtained from the models and the experimental data, thereby establishing the validity of models for all the four types of liquid membranes. The stirred cell employed in BLM process eliminates emulsification and demulsification processes. It also provides simultaneous contact of the organic liquid membrane phase with aqueous feed and strip phases. Overall rate expressions for extraction and stripping in BLM are based on an assumed kinetic mechanism to explain the process qualitatively. It was found that the magnitude^ of diffusional and kinetic resistances determines the overall mass transfer coefficient. The relative magnitude of mass transfer coefficient, reaction rate constants and equilibrium constants enables to visualize the controlling regime of the process. The problem of low flux rate due to high diffusion resistances, inefficient operation and exorbitant costs encountered in bulk and supported liquid membranes (SLM) are overcome in an ELM. In the ELM process, an emulsion of organic membrane phase and aqueous inner phase, is dispersed in the continuous aqueous feed phase. This gives a highly selective and ultra thin liquid film generating a large mass transfer area for separation. Experimental results on membrane instability and emulsion swelling indicate that volumetric leakage rate depends linearly on the stirring speed and that the nature of surfactant does not have any appreciable effect on emulsion swelling. A general permeation model was developed taking into account the external mass transfer around the emulsion drop, diffusion in the drop, reaction at the aqueous-organic interface, leakage of the internal phase to the external phase due to membrane breakup and emulsion swelling due to osmotic pressure difference. Model equations with appropriate boundary conditions were numerically solved by orthogonal collocation technique for a set of model parameters obtained either from known correlations or from independent experiments. Comparison of the model predictions with experimental data from the batch permeation of chromium and other metals using carrier Alamine 336 or LIX 64N, shows that the model predictions are in very good agreement with the experimental findings. Further this model can be used to simulate the effects of various experimental conditions such as metal and hydrogen ion concentrations, carrier concentration, drop diameters, etc., for similar systems. Studies on ESPLIM were conducted with the aim of demonstrating the effectiveness of this new separation process and to develop a simple transport model for metal permeation. In the ESPLIM process, a high electrical field (3-5 kV A.C.) is used for phase dispersion. This system consists of a rectangular reactor filled with membrane solution divided into extraction and stripping cells by a centrally placed integrated type baffle which also acts as an electrode. Two more electrodes were placed in the extraction and stripping cells, where feed and strip phases are introduced from the top of the reactor. When high electrical field is applied across the electrodes, fine droplets of feed and strip are formed and are dispersed in extraction and stripping cells where simultaneous extraction and stripping occurs. The process can be viewed as simultaneous counter current extraction and stripping. The aqueous drops coalesce in the settlers at the bottom of the reactor and are removed continuously. Steady state mass transport model proposed for ESPLIM system accounts for the vertical counter-current extraction and stripping processes taking place in the extraction and stripping cells, together with the lateral transport process of the metal-complex and carrier across the two cells through the integrated baffle zone. The model equations were solved analytically to obtain concentration profiles as a function of the height of the reactor. The required parameters such as mass transfer coefficients, diffusion coefficients etc. were estimated using different correlations. Model predictions agreed remarkably well with the experimental data under various process conditions. From this investigation, it was found that ESPLIM is a simple, efficient and economical process and can be applied in a variety of situations. Based on a suitable combination of solvent extraction, dispersion and liquid membrane technique, a new type of separation system called " Unified Liquid Membrane " was developed. The ULM unit was designed and fabricated, and experiments were conducted to evaluate its performance. The ULM is basically derived from ESPLIM by changing the reactor, baffle design and dispersion technique. Aqueous feed and strip phases were atomized using compressed air through a fine nozzle and are dispersed on either side of an integrated baffle plate that divides the reactor into extraction and stripping cells. Tapering bottom of the reactor reduces the dead volume of the liquid in the settlers and the baffle plate remarkably reduces the leakage problem as well as the resistance through the baffle. Experiments were conducted using LIX 64N and Alamine 336 as carriers for copper and chromium and / or zinc. Mass transport model proposed considers both chemical and phase equilibria in extraction and stripping cells, vertical and lateral transport of carrier and complex across the extraction and stripping cells through the baffle zone. The model equations were solved using initial conditions at the top of the reactor, and equilibrium data for extraction and stripping cells. Effect of various experimental conditions and process parameters was simulated using this model and the model predictions are found to be in excellent agreement with the experimental data. The ULM system developed in this investigation overcomes the major limitations encountered with the other types of liquid membranes while retaining all the advantages of this technology. The problem of high mass transfer resistance from bulk phase to metal permeation as in the case of BLM was eliminated by good phase dispersion. Additional resistance to mass transport from solid membrane as in the case of SLM was removed by using an integrated baffle which also avoids problems of membrane instability, pore clogging and selectivity. The complex problems of emulsification and demulsification were completely eliminated making the system much simpler and efficient. Very good phase dispersion was obtained by atomization without the need for either stirring the whole system or application of high electrical field in the reactor. The membrane liquid within the integrated baffle elements allows easy transport of different species between extraction and stripping cells while completely preventing the mixing of the two aqueous phases. The problems of leakage, swelling and occlusion were avoided due to very short residence time of the aqueous drops in the reactor. It was found that the new ULM configuration is simple, elegant, highly efficient and superior to the other types of liquid membrane systems.

The objective of this study was to investigate the feasibility of the application of low cost high capacity inorganic ion exchange material, synthesized form collected fly ash and acid mine drainage solid residues, for the decontamination of secondary co-disposal process waters, with emphasis on investigating the processes governing the solid/solution interface.

CAPES; CNPq / In the activated sludge process, problems of foaming and filamentous bulking can occur due to overgrowth of certain filamentous bacteria. Nowadays, these microorganisms are typically monitored by means of light microscopy combined with staining techniques. As drawbacks, these methods are susceptible to human errors, subjectivity and limited by the use of discontinuous microscopy. The present project aims the application of an in situ microscope (ISM) for continuous monitoring of filamentous bacteria, providing real-time examination, automated analysis and elimination of sampling, preparation and transport of samples. The ISM previously developed at the Hochschule Mannheim required adaptations for use within wastewater environment, specially in terms of impermeability and development of a cleaning mechanism. With a new objective lens design, the system was simplified to a single tubus and an externally activated cleaning system based on magnetism was created. A proper image processing algorithm was designed for automated recognition and measurement of filamentous objects, allowing real-time evaluation of images without any staining, phase-contrast or dilution techniques. Three main operations are performed: preprocessing and binarization; recognition of filaments using distance-maps and shape descriptors; measurement and display of total extended filament length. A 3D-printed prototype was used for experiments with respect to the new ISM’s design, providing images with resolution very close to the ones acquired with the previous microscope. The designed cleaning system has shown to be effective, removing dirt settled above the lens during tests. For evaluation of the image processing algorithm, samples from an industrial activated sludge plant were collected weekly for a period of twelve months and imaged without any prior conditioning, replicating real environment conditions. Experiments have shown that the developed algorithm correctly identifies trends of filament growth rate, which is the most important parameter for decision making. For reference images whose filaments were marked by specialists, the algorithm correctly recognized 72% of the filaments pixels, with a false positive rate of at most 14%. An average execution time of 0.7 second per image was achieved, demonstrating the algorithm suitability for real-time monitoring. / Em processos de lodo ativado, problemas de foaming e filamentous bulking podem ocorrer devido ao crescimento exagerado de bactérias filamentosas. Atualmente, o monitoramento de tais micro-organismos é feito por meio de métodos baseados em microscopia ótica combinada com técnicas de marcadores, os quais apresentam limitações intrínsecas da microscopia descontínua, são subjetivos e suscetíveis a erro humano. O presente projeto visa a aplicação de um microscópio in situ (ISM) para monitoramento contínuo de bactérias filamentosas, de forma a possibilitar análise instantânea, computadorizada, sem necessidades de recolher, preparar e transportar amostras. O ISM previamente desenvolvido na Hochschule Mannheim teve que ser adaptado para análise de águas residuais, especialmente em termos de impermeabilidade e a criação de um mecanismo de limpeza. Com a utilização de uma nova objetiva, o novo ISM foi simplificado para um tubo único e um sistema de limpeza ativado externamente baseado em magnetismo foi criado. Um algoritmo de processamento de imagens foi elaborado para reconhecimento e medição de comprimento de estruturas filamentosas, permitindo avaliação em tempo real de imagens sem qualquer técnica de marcadores, contraste de fase ou diluição. O mesmo consiste em três operações principais: pré-processamento e binarização; reconhecimento de filamentos por meio de mapeamento de dis- tâncias e descritores de forma; e, finalmente, medição e visualização do comprimento de cada filamento. Um protótipo construído via impressão 3D foi utilizado para avaliação o novo design do microscópio, fornecendo imagens com resolução bastante próxima das adquiridas com a versão anterior do sistema. O mecanismo de limpeza desenvolvido mostrou-se efetivo, capaz de remover partículas sedimentadas acima das lentes durante os testes. Para avaliação do algoritmo de processamento de imagens, amostras de uma planta industrial de lodo ativado foram coletadas semanalmente por um período de doze meses e imageadas sem qualquer condicionamento prévio, replicando condições reais de ambiente. Experimentos demonstraram que o algoritmo desenvolvido identifica corretamente tendências de aumento/decréscimo da concentração de filamentos, o que constitui o principal parâmetro para tomadas de decisão. Para imagens de referência cujos filamentos foram marcados por especialistas, o algoritmo reconheceu corretamente 80% dos pixels atribuídos a filamentos, com uma taxa de falso positivos de até 24%. Um tempo de execução médio de 0,7 segundo por imagem foi obtido, provando sua aptidão para formar uma ferramenta de monitoramento em tempo real.