The combination of moving bed biofilm reactors and membrane bioreactors (MBBR-MR) can compensate for the drawbacks of both of these systems and further increase their acceptance and application in wastewater treatment industries. Despite the potential benefits of a MBBR-MR technology there has only been limited study of this configuration. The present study consisted of an overall assessment of the performance of a combined MBBR-MR system under high and low loading rates. Since colloidal matter in mixed liquor suspended solid (MLSS) is considered as one of the important contributors to membrane fouling, pre-treatment of membrane feed by coagulation was investigated for improving membrane performance. The performance of the MBBR-MR was assessed based on its chemical oxygen demand (COD) removal efficiency and membrane fouling mechanisms. The study was carried out using pilot-scale MBBR and bench-scale batch membrane filtration setups (Millipore Inc. Bedford, MA). The pilot MBBR had a working volume of 1.8 m3 and a 30% carrier fill fraction. The MBBR was operated with loading rates of 160 ± 44 g/m2/d (hydraulic residence time (HRT) of 4.6 h) and 223 g/m2/d (HRT of 2.6 h). The MBBR feed was obtained from a starch recovery line in a potato chip processing factory. The carriers were mixed by coarse bubble aeration and the dissolved oxygen (DO) was maintained above 2 mg/l. Preliminary jar test trials (based on turbidity removal) were performed in order to obtain an optimal dosage of coagulants for subsequent ultrafiltration (UF) tests. The efficiency of three coagulants (alum, ferric chloride and a blend of polyaluminum chloride and polyamine) was evaluated. The membranes were composed of polyethersulfone (PES) and had a pore size of 0.05 microns. The results of this study indicate that the combination of MBBR with membrane filtration can be operated at relatively high loading rates to yield a constant high quality permeate that is suitable for water reuse purposes. Fouling of the membrane by the wastewater was found to be substantially reduced by treatment with the MBBR. The reversible and irreversible fouling of the MBBR effluent were 56 and 63%, respectively, of that observed with the raw wastewater. The MBBR Loading-rate was found to affect treatment efficiency of the MBBR-MR and membrane performance. Operation under the elevated loading-rate conditions HRT = 2.6 hours) resulted in an increase in the irreversible fouling of the membranes (60% on average). The addition of all the coagulants in this study was found to decrease the fouling of the membrane. However, the extent of the pre-coagulation effect on membrane fouling was found to strongly depend on the type and dosage of the coagulant and the MBBR effluent characteristics. All the coagulants were effective in decreasing membrane fouling at their optimal dosages which was determined in preliminary jar tests. Ferric chloride performed the best as a pretreatment coagulant compared to alum (Aluminum sulfate) and the coagulant blend with reductions in both reversible and irreversible fouling (43-86% and 51-71%, respectively) and increased consistency (in decreasing fouling) as compared to the other coagulants. Alum had no effect on irreversible fouling and the coagulant blend significantly increased irreversible fouling in some trials (up to 196% or by a factor of 3 when overdosed). Additionally, alum and the blend were, on average, 29% and 7%, less effective than ferric chloride in reducing reversible fouling under the conditions and dosages tested.

The aim of the present work about experimental and mathematical modelling of moving-bed-gasification was to increase the transparency of the process. At Dresden University of Technology a gasifier with a high number of measuring points was used. Two-dimensional profiles of temperature and gas-concentrations were analysed. Samples of particles taken out of the reactor gave information about drying, pyrolysis and char-reactions. A commercial CFD-software was modified for the special application of fixed-bedgasifiers by subroutines. Comparisons of the results of experiment and simulation showed the constitutive process with its significant reaction-behaviour. By variation of different parameters, important influences were discussed. / Das Ziel der Arbeit war die Erhöhung der Prozeßtransparenz der Festbettvergasung im kleinen Leistungsbereich. Es besteht einerseits eine große Wissenslücke, welche einen durchschlagenden Erfolg für den Brennstoff Holz bisher verhinderte. Andererseits besitzt die Technologie ein energiewirtschaftlich bedeutendes und unter den gegenwärtigen politischen Rahmenbedingungen betriebswirtschaftlich hohes Potential. Ein Modellvergaser war mit umfangreichen Meßmöglichkeiten ausgerüstet. Mittels daran angepaßter Probenahmevorrichtungen konnten in den Untersuchungen auf der Basis von 16 Stützstellen zweidimensionale Profile der Temperatur und der Gaszusammensetzung ermittelt werden. Die Partikelproben aus drei Meßebenen gaben Auskunft über den Trocknungs- und Pyrolysefortschritt sowie über den Koksumsatz. Parallel erfolgte die Erarbeitung einer Mathematischen Modellierung. Hier wurde eine kommerzielle Strömungssimulations-Software mittels Unterprogramme an die Anforderungen der Festbettvergasung angepaßt. Im Vergleich der Ergebnisse aus Experiment und Simulation konnte der Reaktionsablauf dargestellt, sowie Einflüsse verschiedener Parameter auf den Prozeß diskutiert werden.

The combination of moving bed biofilm reactors and membrane bioreactors (MBBR-MR) can compensate for the drawbacks of both of these systems and further increase their acceptance and application in wastewater treatment industries. Despite the potential benefits of a MBBR-MR technology there has only been limited study of this configuration. The present study consisted of an overall assessment of the performance of a combined MBBR-MR system under high and low loading rates. Since colloidal matter in mixed liquor suspended solid (MLSS) is considered as one of the important contributors to membrane fouling, pre-treatment of membrane feed by coagulation was investigated for improving membrane performance. The performance of the MBBR-MR was assessed based on its chemical oxygen demand (COD) removal efficiency and membrane fouling mechanisms. The study was carried out using pilot-scale MBBR and bench-scale batch membrane filtration setups (Millipore Inc. Bedford, MA). The pilot MBBR had a working volume of 1.8 m3 and a 30% carrier fill fraction. The MBBR was operated with loading rates of 160 ± 44 g/m2/d (hydraulic residence time (HRT) of 4.6 h) and 223 g/m2/d (HRT of 2.6 h). The MBBR feed was obtained from a starch recovery line in a potato chip processing factory. The carriers were mixed by coarse bubble aeration and the dissolved oxygen (DO) was maintained above 2 mg/l. Preliminary jar test trials (based on turbidity removal) were performed in order to obtain an optimal dosage of coagulants for subsequent ultrafiltration (UF) tests. The efficiency of three coagulants (alum, ferric chloride and a blend of polyaluminum chloride and polyamine) was evaluated. The membranes were composed of polyethersulfone (PES) and had a pore size of 0.05 microns. The results of this study indicate that the combination of MBBR with membrane filtration can be operated at relatively high loading rates to yield a constant high quality permeate that is suitable for water reuse purposes. Fouling of the membrane by the wastewater was found to be substantially reduced by treatment with the MBBR. The reversible and irreversible fouling of the MBBR effluent were 56 and 63%, respectively, of that observed with the raw wastewater. The MBBR Loading-rate was found to affect treatment efficiency of the MBBR-MR and membrane performance. Operation under the elevated loading-rate conditions HRT = 2.6 hours) resulted in an increase in the irreversible fouling of the membranes (60% on average). The addition of all the coagulants in this study was found to decrease the fouling of the membrane. However, the extent of the pre-coagulation effect on membrane fouling was found to strongly depend on the type and dosage of the coagulant and the MBBR effluent characteristics. All the coagulants were effective in decreasing membrane fouling at their optimal dosages which was determined in preliminary jar tests. Ferric chloride performed the best as a pretreatment coagulant compared to alum (Aluminum sulfate) and the coagulant blend with reductions in both reversible and irreversible fouling (43-86% and 51-71%, respectively) and increased consistency (in decreasing fouling) as compared to the other coagulants. Alum had no effect on irreversible fouling and the coagulant blend significantly increased irreversible fouling in some trials (up to 196% or by a factor of 3 when overdosed). Additionally, alum and the blend were, on average, 29% and 7%, less effective than ferric chloride in reducing reversible fouling under the conditions and dosages tested.

The past few years have seen an upsurge in the use of renewable biomass as a source of energy due to growing concerns over greenhouse gas emissions caused by the combustion of fossil fuels and the need for energy independence due to depleting fossil fuel resources. Although coal will continue to be a major source of energy for many years, there is still great interest in replacing part of the coal used in energy generation with renewable biomass. Combustion converts inherent chemical energy of carbonaceous feedstock to only thermal energy. On the other hand, partial oxidation processes like gasification convert chemical energy into thermal energy as well as synthesis gas which can be easily stored or transported using existing infrastructure for downstream chemical conversion to higher value specialty chemicals as well as production of heat, hydrogen, and power. Devolatilization or pyrolysis plays an important role during gasification and is considered to be the starting point for all heterogeneous gasification reactions. Pyrolysis kinetic modeling is, therefore, an important step in analyzing interactions between blended feedstocks. The thermal evolution profiles of different coal-biomass blends were investigated at various heating rates using thermogravimetric analysis. Using MATLAB, complex models for devolatilization of the blends were solved for obtaining and predicting the global kinetic parameters. Parallel first order reactions model, distributed activation energy model and matrix inversion algorithm were utilized and compared for this purpose. Using these global kinetic parameters, devolatilization rates of unknown fuel blends gasified at unknown heating rates can be accurately predicted using the matrix inversion method. A unique laboratory scale auto-thermal moving bed gasifier was also designed and constructed for studying the thermochemical conversion of coal-biomass blends. The effect of varying operating parameters was analyzed for optimizing syngas production. In addition, stable carbon isotope analysis using Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry (GC-C-IRMS) was used for qualitatively and quantitatively measuring individual contributions of coal and biomass feedstocks for generation of carbonaceous gases during gasification. The predictive models utilized and experimental data obtained via these methods can provide valuable information for analyzing synergistic interactions between feedstocks and also for process modeling and optimization.

There is an urgent need to develop ammonia removal treatment systems for municipal and industrial wastewater treatment due to the increasingly stringent ammonia effluent discharge regulations implemented by Canada, the United States, and the European Union. The objective of this dissertation is to develop new understanding and advance the current design and operation of total ammonia nitrogen (TAN) removal via the moving bed biofilm reactor technology (MBBR) for municipal and industrial wastewaters. The first specific objective is to develop a passive, low operationally intensive, efficient and robust design strategy for municipal wastewater treatment to achieve partial nitritation (PN) as a pre-treatment to anammox treatment without using control strategies such as operating at low dissolved oxygen, or the use of inhibitors. This first objective includes developing new knowledge of the biofilm, biomass and microbiome of attached growth PN systems. The second specific objective is to investigate the impact of defining a maximum biofilm thickness, via bio-carrier design, to enhance the effects of free nitrous acid inhibition for PN of municipal wastewaters. The third objective is to investigate the effect of influent copper concentration on nitrifying MBBR systems over long-term operations, to demonstrate the feasibility of the nitrifying MBBR as a solution for TAN removal from gold mining wastewaters. The results pertaining to the first objective, achieved via a study investigating the operation of a nitrifying moving bed biofilm reactor at elevated TAN surface area loading rates (SALRs) of 3, 4, 5, and 6.5 g TAN/m²∙d with the aim of achieving passive PN, demonstrates that operating at a TAN SALR value of 6.5 g TAN/m²∙d can achieve PN without restricting dissolved oxygen or using inhibitors. Operating at a TAN SALR value of 6.5 g TAN/m²∙d achieves a TAN surface area removal rate (SARR) of 3.5 g TAN/m²∙d, and a nitrite accumulation of 99.8% of the oxidized TAN, demonstrating the suppression of nitrite oxidizing bacteria (NOB) activity, while achieving elevated TAN SARR values. At the molecular-scale, there is a statistically significant change in the ammonia oxidizing bacteria (AOB) to NOB ratio from 1:2.6 to 8.7:1 as the TAN SALR increases from 3 to 6.5 g TAN/m²∙d; however, even at a TAN SALR value of 6.5 g TAN/m²∙d there is an NOB abundance of approximately 2%; thus demonstrating that NOB remain present in the biofilm, while their activity is suppressed by operation at elevated TAN SALR values. Furthermore, this system was shown to achieve stable PN consistently for over a period of 10 months of operation, demonstrating a robust, passive, low operational strategy for attached growth PN. The second objective of this dissertation is addressed through a study that compared the carrier design of defined maximal biofilm thickness (z-prototype carrier) to undefined maximal biofilm thickness (chip-prototype carrier) for PN via free nitrous acid inhibition of tertiary, low carbon, municipal wastewaters. The study demonstrates that defined maximal biofilm thickness is a preferred design choice to achieve attached growth PN. The chip-prototype carrier shows biofilm thicknesses and biofilm mass values that are ten-fold higher than the z-prototype carrier, which is shown to contribute to the impact of free nitrous acid on AOB and NOB activities. The z-prototype carrier shows PN is achieved after 3 hours of exposure to free nitrous acid while the chip-prototype carrier does not achieve PN within this same time of exposure. Therefore, the defined maximal biofilm thickness carrier is identified in this research as the preferred design option to achieve attached growth PN for municipal, low carbon, tertiary wastewater treatment. The results of the third objective, achieved via a study investigating the effects of influent copper concentrations on nitrifying MBBR during long term operations to gold mining wastewaters, demonstrates that there is no AOB inhibition in attached growth systems exposed to 0.1, 0.3, 0.45, and 0.6 mg Cu/L for long exposure times. A trend of increasing nitrite accumulation with increasing influent copper concentrations is shown, indicating that NOB inhibition occurs at influent copper concentrations of 0.3 mg Cu/L and greater, with the greatest NOB inhibition observed with an influent copper concentration of 0.6 mg/L. There is no statistically significant difference in biofilm characteristics at the copper concentrations tested; however, there is a trend of increasing biofilm thickness and biofilm roughness with increasing copper concentrations. This study demonstrates the resilience of the nitrifying biofilm to copper inhibition and demonstrates that the nitrifying MBBR is a promising system for removing TAN in mining wastewater in the presence of copper.

The nitrification process, the biologically mediated process of ammonia treatment in water resources recovery facilities (WRRF), remains the most common treatment process to mitigate the adverse effects of effluent ammonia discharges in surface water. However, it is well established that the temperature-sensitive process of nitrification remains hindered at low temperatures in conventional suspended growth technologies; specifically, passive treatment systems such as the lagoons, representing over 50% of Canadian treatment facilities in operation. As such, nitrification in lagoon facilities remains unreliable during the cold seasons with no nitrification occurring at 1°C. In contrast to suspended growth systems, attached growth technologies such as the moving bed biofilm reactors (MBBR) have recently been proven capable of achieving significant nitrification rates at temperatures as low as 1°C and are proposed as suitable upgrade systems to the common lagoon facility to reach year-long ammonia treatment targets. As such, the main objective of this research is to investigate and expand the current knowledge by investigating the key research questions lacking in the current literature on post-carbon, low temperature nitrifying MBBR systems. With this aim, a temperature-controlled study of attached growth nitrification kinetics was conducted to isolate the effects of low temperatures on nitrifying MBBR system performance down to 1°C. A removal rate of 98.44 ± 4.69 gN/m³d is identified as the 1°C intrinsic removal rate and the design removal rate for nitrifying MBBR systems at low temperatures. Considering this intrinsic rate at 1°C, an assessment of reactor efficiency at elevated TAN concentrations typical of non-combined sewer systems indicates that a two reactor in-series MBBR system configuration is recommended for retrofitting lagoon facilities connected to sanitary sewers. The study of the reactor performance to temperatures as low as 1°C demonstrates a non-linear decline in removal efficiency between 10°C and 1°C, with the existence of a kinetic threshold temperature delineated between 4°C and 2°C. As such, this delineated temperature range accounts for a significant decline in the performance of low carbon nitrifying MBBR systems during the onset of the cold seasons. This research identifies new recommended Arrhenius correction coefficient values taking into account this kinetic threshold temperature, with a coefficient of 1.049 being recommended above the kinetic threshold (≥4°C) and 1.149 below the threshold temperature at 1°C. Moreover, since the elapsed time to low temperature was identified as a key factor of attached growth nitrification kinetics, a modified theta model accounting for temperature and time is proposed in this research to accurately model the rate of nitrifying MBBR systems between 4°C and 1°C. Finally, with the severe adverse effects of sudden decreases in temperature, or cold shocks, on nitrification kinetics being previously demonstrated but not well understood, this research compares acclimatized and cold shocked MBBR reactors down to 1°C. The findings indicate 21% lower kinetics in the cold shocked reactor with reactor efficiencies never reaching those of the acclimatized reactor despite extended operation at 1°C. Thus, the research delineates the potentially lasting effects of extreme weather events such as cold air outbreaks and snowmelt periods on nitrifying MBBR system performance. On the other hand, these same findings demonstrate the resiliency of nitrifying MBBR reactors as nitrification was maintained within these systems despite being cold-shocked down from 10°C and 1°C. This study of attached growth kinetics was coupled with an investigation of the nitrifying biofilms, biomass, and microbiome responses to low temperatures and cold shock down to 1°C to provide an understanding of the changes occurring in these systems down to the cellular level. Comparisons of acclimatized and cold shocked nitrifying biofilms responses down to 1°C were characterized by increases in biofilm thickness, increases in biomass viability; and, greater shifts in microbiome communities occurring above 4°C in the acclimatized biofilm. Considering these observations, results also indicated a significant increase in nitrifiers per carrier above 4°C. As such, these findings suggested that the bulk of nitrifying biofilm adaptation to cold temperatures occurs above 4°C, a crucial adaptation phase in acclimatized systems. This adaptation phase is shown to be lacking in cold-shocked systems, with the cold shocked biofilm and microbiome demonstrating significant differences with the acclimatized systems’ biofilm and microbiome. This research was performed to answer the critical research questions relating to the design and operation of the post-carbon, low temperature nitrifying MBBR systems, with the first low temperature MBBR systems being scheduled to begin operation in the fall of 2020. This research expands the current knowledge on low temperature attached growth nitrification kinetics as well as cold shocked attached growth nitrification kinetics in MBBR systems down to 1°C. In addition, this research delineates the effects of low temperatures and cold shocks on the nitrifying MBBR system’s biofilms and their embedded cells.

Les procédés chromatographiques multicolonnes continus se sont imposés comme technique séparative dans l’industrie pharmaceutique en raison de leur productivité élevée et de leur développement rapide. De nos jours, la modélisation, le dimensionnement et l’optimisation des procédés LMS et Varicol sont considérés comme établis. Le fonctionnement automatique optimisé et robuste de ces procédés reste cependant un sujet de recherche. Le plus souvent, les paramètres opératoires sont choisis en deçà du réglage optimal afin d’inclure une marge de robustesse. Ils sont ajustés manuellement par un opérateur expérimenté pour maintenir les produits à leurs spécifications de pureté. Le nombre élevé de séparations chromatographiques rend crucial le développement d’une application d’un contrôle avancé de ces procédés. Récemment, plusieurs méthodes de contrôle des procédés LMS ont été proposées. Ce travail de thèse présente une nouvelle approche de contrôle avancé. Cette commande ajuste les paramètres opératoires d’une séparation grâce à deux types de mesure : une mesure en ligne et une mesure hors ligne. Une validation expérimentale du schéma de contrôle a été effectuée sur un procédé Varicol. Les résultats présentés démontrent que la commande permet d’amener la pureté des produits à leurs spécifications, d’optimiser les performances du procédé et de répondre aux perturbations, tout en sécurisant la pureté du produit cible / Multicolumn continuous chromatographic processes became a key separation technology in the areas of pharmaceutical industry thanks to high productivity and short process development times. Today, modeling, design, and optimization of SMB and Varicol, are well established. However a robust and optimized operation of processes is still an open issue. The common practice is to operate processes under suboptimal operating conditions in order to gain the necessary robustness. The operating parameters are tuned manually by experienced operators in order to maintain the product specifications. Therefore, as chromatographic applications spread, process control problem becomes increasingly important. Recently, several control methodologies of SMB process have been proposed. This thesis work introduces a new advanced control system approach. This system adjusts operating parameters thanks to two kinds of measurements : an in-line measurement and an at-line measurement. The performance of this control scheme is demonstrated through several experiments on Varicol. The reported results aim to demonstrate that the controller is able to deliver the products within the specifications, to optimize the process performance and to answer to disturbances while protecting the key product

Introdução sistemas de tratamento de esgotos, quando aplicados ao tratamento de lixiviado de aterro sanitário, não têm apresentado bons resultados. Por conta disso, faz-se necessário o desenvolvimento de alternativas para o tratamento de lixiviado. Objetivo avaliar o pós-tratamento de lixiviado de aterro sanitário por wetland construído de fluxo subsuperficial horizontal e reator biológico de leito móvel (RBLM). Materiais e métodos foram realizados dois experimentos com tratamento de lixiviado após remoção de amônia por dessorção. No experimento 1 utilizou-se wetlands construídos de fluxo horizontal em escala de bancada (volume total de 30,8 L), plantados com Cyperus papyrus, Heliconia psittacorum e Gynerium sagittatum, e um controle sem vegetação, preenchidos com pedrisco calcário. O sistema foi alimentado com lixiviado diluído em água em diferentes proporções (entre 10 por cento e 30 por cento ) com concentração média de DQO entre 336 e 750 mg.L-1 e nitrogênio amoniacal (N-NH4) entre 47 e 199 mg.L-1. A operação ocorreu em três etapas: (1ª) alimentação contínua e TDH médio entre 2,7 e 5,3 d; (2ª) regime de ciclos de recirculação do efluente, para avaliar o efeito do aumento de TDH para 21 dias; (3ª) alimentação contínua de duas unidades wetlands em série, visando elevar o TDH (entre 8,1 e 9,9 d) sem recirculação. O experimento 2 foi implantado em escala piloto, com uma unidade de dessorção de amônia seguida de um Reator Biológico de Leito Móvel (RBLM) e um biofiltro anóxico. O RBLM (volume efetivo de 380 L) foi preenchido em 50 por cento com anel pall. Resultados e discussão No experimento 1, obteve-se baixa remoção de DQO com médias inferiores a 40 por cento e concentração final entre 270 e 750 mg.L-1. No entanto, verificou-se remoção de N-NH4, principalmente na 2ª e 3ª etapas, com médias de remoção entre 43 por cento e 81 por cento , resultando em concentração de 20 a 223 mg.L-1, com influência do TDH. No experimento 2, problemas técnicos durante a instalação e operação inicial e interdição do campus da USP-Leste prejudicaram a adaptação do reator e impediram o seu monitoramento por tempo suficiente para geração de dados consistentes, sendo interrompido na fase inicial. Conclusões A baixa eficiência para DQO provavelmente está relacionada à recalcitrância do lixiviado, ou devido à inibição dos microrganismos por toxicidade. Quanto ao N-NH4, infere-se que o aumento do TDH proporcionou maior tempo de difusão de oxigênio para o sistema wetland, suprindo a demanda das bactérias heterotróficas, o que possibilitou utilização do oxigênio excedente pelas nitrificantes, culminando na oxidação do N-NH4. / Introduction sewage treatment systems, when applied to the treatment of landfill leachate, have not shown good results. Thus it is necessary to develop alternatives for the treatment of leachate. Objective To assess the post-treatment of landfill leachate by horizontal subsurface flow constructed wetland and moving bed biofilm reactor (MBBR). Materials and methods Two experiments were conducted with treatment of the leachate after removal of ammonia by stripping. In experiment 1, horizontal flow constructed wetlands, at bench scale (total volume of 30.8 L), planted with Cyperus papyrus, Heliconia psittacorum and Gynerium sagittatum, and a control without vegetation, were filled with calcareous gravel. The system was fed with leachate diluted in water with different proportions (between 10 per cent and 30 per cent ) with mean COD concentration of between 336 and 750 mg.L-1 and ammonia nitrogen (NH4-N) between 47 and 199 mg L-1. The operation was divided in three stages: (1st) continuous feeding with mean HRT between 2.7 and 5.3 d; (2nd) regime of effluent recirculation to evaluate the effect of increasing the HRT to 21 days; (3rd) continuous feeding with two wetlands units in series, aimed HRT increasing (between 8.1 and 9.9 d) without recirculation. Experiment 2 was implemented on a pilot scale, with a unit of ammonia stripping followed by MBBR and an anoxic biofilter. The MBBR (380 L working volume) was filled 50 per cent with pall ring. Results and discussion In experiment 1, the COD removal was low, with averages below 40 per cent , with effluent concentration between 270 and 750 mg.L-1. However, there was removal of NH4-N, especially in the 2nd and 3rd stages, with average removal between 43 per cent and 81 per cent , resulting in concentration between 20 and 223 mg.L-1, with HRT influence. In experiment 2, technical problems during the installation and initial operation and interdiction of the campus of USP-Leste disrupted the reactor acclimation and precluded the monitoring for sufficient time to generate consistent data for discussion. Conclusions The low efficiency for COD is probably related to the recalcitrance of the leachate, or due to inhibition of microorganisms by toxicity. For NH4-N, it is inferred that the increase of the HRT provided greater time for diffusion of oxygen to the wetland system, meeting the demand of heterotrophic bacteria, which allowed the use of excess oxygen by nitrifiers, culminating in the oxidation of NH4-N.

O lançamento de águas residuárias contendo compostos nitrogenados tem um importante impacto sobre a saúde e o meio ambiente, tornando necessária a incorporação de processos de remoção desses compostos nos sistemas de tratamento de águas residuárias. Neste trabalho, foram estudadas as condições de operação para promover a remoção conjunta de nitrogênio e matéria orgânica em reator biológico de leito móvel, contínuo, operado sob aeração intermitente, alimentado com água residuária sintética contendo nitrogênio amoniacal (90 a 110 mg/L) e melaço como matéria orgânica (DQO de 450 a 550 mg/L). Foram utilizados dois reatores em escala de bancada, cada um com dois litros de volume útil, contendo diferentes meios suportes para a imobilização da biomassa: matrizes de espuma de poliuretano e anéis plásticos. Na primeira etapa experimental, o reator contendo anéis plásticos apresentou eficiências de remoção de nitrogênio muito baixas. Na segunda etapa, trocou-se o material suporte por matrizes de espuma de poliuretano inoculadas com lodo aeróbio de estação de tratamento de águas residuárias. A partir de então, trabalhou-se com dois reatores de mesma configuração, exceto pelas origens, idades e características dos lodos de inóculo. Inicialmente, a alimentação foi realizada utilizando-se apenas os micronutrientes contidos no melaço. Posteriormente, a composição da água residuária foi alterada, introduzindo-se solução de micronutrientes, pois se concluiu que a instabilidade no processo de nitrificação devia-se ao fato de o melaço comercial apresentar deficiências nutricionais. Como resultado, em condições de estabilidade operacional, foram obtidas eficiências de remoção de DQO superiores a 85%, oxidação total do nitrogênio amoniacal e eficiências de remoção de nitrogênio de aproximadamente 55%. Variações posteriores nas condições de operação, como o aumento do período anóxico (de 1h para 1h15min) e redução do tempo de detenção hidráulica (para valores inferiores a 12 horas), resultaram em melhora no desempenho dos reatores. Os resultados obtidos permitem admitir que as melhores condições de operação não foram atingidas durante o experimento, abrindo a possibilidade para a otimização do processo em pesquisas futuras. Constatou-se que o desenvolvimento das populações microbianas imobilizadas no meio suporte foi diferente do observado na biomassa em suspensão. Verificou-se, também, que a biomassa responsável pela nitrificação e desnitrificação ocorreu predominantemente no meio suporte, enquanto que a biomassa heterotrófica predominou no lodo em suspensão. / The operating conditions for the combined removal of nitrogen and organic matter in moving- bed biological reactor were investigated. Two bench-scale reactors, two liters each, were operated under intermittent aeration and continuously fed with synthetic wastewater containing ammonia nitrogen (90 to 110 mg/L) and molasses as organic carbon source (COD of 450 to 550 mg/L). Each reactor received different moving-bed materials: polyurethane foam matrices and plastic rings, respectively. During the first experimental period, the reactor containing plastic rings maintained very low nitrogen removal efficiencies during large period. For this reason, the moving-bed was replaced by polyurethane foam matrices and the reactor was re-inoculated with aerobic wastewater plant sludge. Thereafter, the two reactors were similar except for the origin, age and characteristics of the inoculum sludge. First, the wastewater micronutrients were just those contained in the carbon source (molasses). After, the synthetic wastewater composition was changed by adding a solution of micronutrients. This procedure was adopted to achieve a stable nitrification process, because commercial molasses is a very poor regarding its micronutrient composition. As a result of the stable conditions prevalence just after adding micronutrients, organic matter (as COD) removal efficiencies were higher than 85% and complete nitrogen ammonia oxidation was achieved. In nitrogen removal efficiencies were approximately 55%. The performance of the reactors improved after the increase of the anoxic period from1h to 1h15min, and reduction of the hydraulic detention time to less than 12 h. The results obtained in the last operating period indicated the optimum operating conditions was not achieved in this experiment, thus opening the possibility of process improvement in further researches. Microbial populations with different characteristics were developed in suspended growth and attached biomass. Nitrification and denitrification bacteria predominated as attached biomass whereas heterotrophic bacteria predominated as suspended growth biomass.

Introdução sistemas de tratamento de esgotos, quando aplicados ao tratamento de lixiviado de aterro sanitário, não têm apresentado bons resultados. Por conta disso, faz-se necessário o desenvolvimento de alternativas para o tratamento de lixiviado. Objetivo avaliar o pós-tratamento de lixiviado de aterro sanitário por wetland construído de fluxo subsuperficial horizontal e reator biológico de leito móvel (RBLM). Materiais e métodos foram realizados dois experimentos com tratamento de lixiviado após remoção de amônia por dessorção. No experimento 1 utilizou-se wetlands construídos de fluxo horizontal em escala de bancada (volume total de 30,8 L), plantados com Cyperus papyrus, Heliconia psittacorum e Gynerium sagittatum, e um controle sem vegetação, preenchidos com pedrisco calcário. O sistema foi alimentado com lixiviado diluído em água em diferentes proporções (entre 10 por cento e 30 por cento ) com concentração média de DQO entre 336 e 750 mg.L-1 e nitrogênio amoniacal (N-NH4) entre 47 e 199 mg.L-1. A operação ocorreu em três etapas: (1ª) alimentação contínua e TDH médio entre 2,7 e 5,3 d; (2ª) regime de ciclos de recirculação do efluente, para avaliar o efeito do aumento de TDH para 21 dias; (3ª) alimentação contínua de duas unidades wetlands em série, visando elevar o TDH (entre 8,1 e 9,9 d) sem recirculação. O experimento 2 foi implantado em escala piloto, com uma unidade de dessorção de amônia seguida de um Reator Biológico de Leito Móvel (RBLM) e um biofiltro anóxico. O RBLM (volume efetivo de 380 L) foi preenchido em 50 por cento com anel pall. Resultados e discussão No experimento 1, obteve-se baixa remoção de DQO com médias inferiores a 40 por cento e concentração final entre 270 e 750 mg.L-1. No entanto, verificou-se remoção de N-NH4, principalmente na 2ª e 3ª etapas, com médias de remoção entre 43 por cento e 81 por cento , resultando em concentração de 20 a 223 mg.L-1, com influência do TDH. No experimento 2, problemas técnicos durante a instalação e operação inicial e interdição do campus da USP-Leste prejudicaram a adaptação do reator e impediram o seu monitoramento por tempo suficiente para geração de dados consistentes, sendo interrompido na fase inicial. Conclusões A baixa eficiência para DQO provavelmente está relacionada à recalcitrância do lixiviado, ou devido à inibição dos microrganismos por toxicidade. Quanto ao N-NH4, infere-se que o aumento do TDH proporcionou maior tempo de difusão de oxigênio para o sistema wetland, suprindo a demanda das bactérias heterotróficas, o que possibilitou utilização do oxigênio excedente pelas nitrificantes, culminando na oxidação do N-NH4. / Introduction sewage treatment systems, when applied to the treatment of landfill leachate, have not shown good results. Thus it is necessary to develop alternatives for the treatment of leachate. Objective To assess the post-treatment of landfill leachate by horizontal subsurface flow constructed wetland and moving bed biofilm reactor (MBBR). Materials and methods Two experiments were conducted with treatment of the leachate after removal of ammonia by stripping. In experiment 1, horizontal flow constructed wetlands, at bench scale (total volume of 30.8 L), planted with Cyperus papyrus, Heliconia psittacorum and Gynerium sagittatum, and a control without vegetation, were filled with calcareous gravel. The system was fed with leachate diluted in water with different proportions (between 10 per cent and 30 per cent ) with mean COD concentration of between 336 and 750 mg.L-1 and ammonia nitrogen (NH4-N) between 47 and 199 mg L-1. The operation was divided in three stages: (1st) continuous feeding with mean HRT between 2.7 and 5.3 d; (2nd) regime of effluent recirculation to evaluate the effect of increasing the HRT to 21 days; (3rd) continuous feeding with two wetlands units in series, aimed HRT increasing (between 8.1 and 9.9 d) without recirculation. Experiment 2 was implemented on a pilot scale, with a unit of ammonia stripping followed by MBBR and an anoxic biofilter. The MBBR (380 L working volume) was filled 50 per cent with pall ring. Results and discussion In experiment 1, the COD removal was low, with averages below 40 per cent , with effluent concentration between 270 and 750 mg.L-1. However, there was removal of NH4-N, especially in the 2nd and 3rd stages, with average removal between 43 per cent and 81 per cent , resulting in concentration between 20 and 223 mg.L-1, with HRT influence. In experiment 2, technical problems during the installation and initial operation and interdiction of the campus of USP-Leste disrupted the reactor acclimation and precluded the monitoring for sufficient time to generate consistent data for discussion. Conclusions The low efficiency for COD is probably related to the recalcitrance of the leachate, or due to inhibition of microorganisms by toxicity. For NH4-N, it is inferred that the increase of the HRT provided greater time for diffusion of oxygen to the wetland system, meeting the demand of heterotrophic bacteria, which allowed the use of excess oxygen by nitrifiers, culminating in the oxidation of NH4-N.