Em reatores biológicos anaeróbios adequadamente projetados, 'SO IND.4'POT.2-' pode ser reduzido a sulfeto pelas bactérias redutoras de sulfato (BRS), o qual, posteriormente, pode ser oxidado a enxofre elementar, em presença de baixas concentrações de oxigênio dissolvido ('< OU =' 0,1 mg/L). Na presente tese, o processo de biodessulfatação foi estudado em reatores anaeróbios operados em bateladas seqüenciais, com biomassa imobilizada em espuma de poliuretano (PU) e em carvão vegetal (CV), previamente selecionados por testes de adesão microbiana em reatores diferenciais. Posteriormente, avaliou-se o efeito de etanol sobre o desempenho do processo de biodessulfatação. As principais rotas de utilização de substratos orgânicos pelos microrganismos foram identificadas por meio de modelação cinética. A comunidade microbiana foi avaliada por hibridação in situ com fluorescência (FISH). Após o processo de biodessulfatação, avaliou-se o processo de oxidação parcial do sulfeto, em reator aeróbio operado em bateladas seqüenciais, com biomassa imobilizada em PU. Concluiu-se por FISH que as características intrínsecas dos materiais suportes influenciam o equilíbrio microbiano. A relação DQO/['SO IND.4'POT.2-'] igual a 1,3 representou a melhor condição para o processo de biodessulfatação, com PU e com CV como materiais suporte, com eficiência média em redução de sulfato igual a 96%. A adição de etanol melhorou o processo de redução de sulfato. Sulfeto gerado no processo de biodessulfatação foi oxidado parcialmente a enxofre elementar, com eficiência de remoção de 80% no reator aeróbio / In anaerobic biological systems for wastewater treatment well-designed sulphate can be reduced to sulfide by sulphate-reducing bacteria (SRB), and it can be subsequently oxidized to elemental sulphur, under low dissolved oxygen concentration ('< OU =' 0.1 mg/L). The present thesis evaluates the microbial sulphate reduction process in anaerobic sequencing batch biofilm reactors with immobilized biomass in polyurethane foam (PU) and vegetable coal (CV). Such support materials were previously selected by microbial adhesion tests executed in differential reactors. Afterwards, the effect of ethanol addition on the performance of sulphate reduction process was assessed. The main metabolic pathways of organic substrate utilization by microorganisms were identified by kinectic modelation. The microbial community was evaluated by fluorescence in situ hybridization (FISH). The partial sulfide oxidation process was also evaluated in aerobic sequencing batch reactor containing biomass immobilized in PU matrices. It was concluded by FISH that characteristics of the support materials has influence on the microbial equilibrium. The COD/['SO IND.4'POT.2-'] ratio equal to 1.3 provided the best condition for microbial sulphate reduction process in both reactors with mean efficience of 96%. The ethanol addition improved the sulphate reducing process. The sulfide generated was partialy oxidized to elemental sulphur in the aerobic reactor with removal efficience of 80%

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The process modeling and simulation is a greatly important procedure for many chemical and biotechnological processes. The process simulation allows to predict elementary behavior of the state variables of the process, leading to many economical and process advantages, such as the avoidance of losses of time and materials for not knowing the process particularities, the safety guarantee, the product quality, and, mostly the process optimization, permitting to study and to reach the best conditions of a process, which shall yield in more products with quality produced with less effort and expenditures. In this work, the modeling and simulation of two biological processes enzymatic hydrolysis and solid state fermentation were performed in order to develop models and estimate parameters that enable an engineer to predict the process behavior and to make decisions about the process. The modeling procedure also involves the computing of differential equations, and algebraic-differential equations; in this manner, the engineer must be able to use different numerical integration methods. Mainly two parameters estimation procedures were used Particle-Swarm Optimization and Levenberg-Marquardt -, and two numerical integration methods were also resorted Runge-Kutta and Dormand-Prince. Experimental data from previous works were used to perform several tests in order to assure that the models were predicting correctly the state variables of the process and, in this manner, were reliable and useful. In the first paper, several mechanistic and empirical models are tested to fit the enzymatic hydrolysis experimental data; statistical tests were performed to verify which of those models would best describe the process, which was found to be and entirely empirical non-autonomous model. The following papers are about the modeling of the solid-state fermentation process. The model was found to be very accurate and adequate to be used for predictions, mainly for the bed temperature of the packed-bed bioreactor, since it could predict the temperature gradients along the time and height of the bed. Also, some numerical procedures such as parameters identifiability, to realize which were the most important parameters to be estimated, and model reparametrization, to reduce the total number of parameters to be estimated and avoid magnitude problems of the model, were successfully performed. This work has shown that the modeling and simulation of processes holds an enormous importance for industry, and different techniques can be applied with more or less effort and success. Further, hopefully, this work has contributed to the state of the art of modeling, in a general way, for biological processes. / A modelagem e a simulação de processos consistem em um recurso de grande importância para diversos processos químicos e biotecnológicos. A simulação de processos nos permite predizer o comportamento das variáveis de estado do processo, levando-nos a vantagens técnicas e econômicas, como, por exemplo, a prevenção de perdas de tempo e insumos por não conhecer particularidades do processo, a garantia de segurança, a qualidade do produto e, principalmente, a otimização do processo, permitindo estudar e alcançar as melhores condições para o referido processo, o que deve culminar em mais produto produzido com melhor qualidade e com menos esforços e custos. Neste trabalho, a modelagem e a simulação de dois processos biotecnológicos hidrólise enzimática e fermentação em estado sólido foram feitas com a validação dos modelos propostos com dados experimentais através da técnica de estimação de parâmetros para permitir ao engenheiro prever o comportamento do processo e tomar decisões. O procedimento de modelagem também envolve a avaliação de equações diferenciais e de equações algébricas, dessa forma, o engenheiro deve estar apto a usar diferentes métodos de integração numérica. Dois procedimentos principais de estimação de parâmetros foram utilizados Otimização por Enxame de Partículas e Levenberg-Marquardt -, e se lançou mão de dois métodos de integração numérica, Runge-Kutta e Dormand-Prince. Dados experimentais de trabalhos anteriores foram utilizados para realizar diversos testes para assegurar a precisão dos modelos em predizer as variáveis de estado do processo e, portanto, serem modelos confiáveis e úteis. No primeiro artigo apresentado, diversos modelos mecanicísticos e empíricos foram testados para se ajustarem aos dados experimentais da hidrólise enzimática; testes estatísticos foram realizados para verificar qual dos modelos melhor descreveria o processo, de forma que o melhor modelo se mostrou ser um modelo totalmente empírico não-autônomo. Os demais artigos tratam da modelagem de um processo de fermentação em estado sólido. Verificou-se que o modelo é bastante preciso e adequado para o uso em predições, principalmente para o perfil de temperatura no leito do biorreator, uma vez que o modelo prevê os gradientes de temperatura ao longo do tempo e da altura do leito. Também, procedimentos numéricos, tais como a análise de identifiabilidade dos parâmetros, para a percepção de quais são os parâmetros mais importantes para a estimação, e a reparametrização do modelo, para reduzir o número total de parâmetros a serem estimados e evitar problemas de magnitude no modelo, foram empregadas com sucesso. Este trabalho mostrou que a modelagem e a simulação de processos possuem enorme importância para a indústria, e diferentes técnicas podem ser aplicadas com maior ou menor esforço e sucesso. Além disso, espera-se que o trabalho tenha contribuído para o estado da arte em modelagem, de uma maneira geral, na área de bioprocessos.

Em reatores biológicos anaeróbios adequadamente projetados, 'SO IND.4'POT.2-' pode ser reduzido a sulfeto pelas bactérias redutoras de sulfato (BRS), o qual, posteriormente, pode ser oxidado a enxofre elementar, em presença de baixas concentrações de oxigênio dissolvido ('< OU =' 0,1 mg/L). Na presente tese, o processo de biodessulfatação foi estudado em reatores anaeróbios operados em bateladas seqüenciais, com biomassa imobilizada em espuma de poliuretano (PU) e em carvão vegetal (CV), previamente selecionados por testes de adesão microbiana em reatores diferenciais. Posteriormente, avaliou-se o efeito de etanol sobre o desempenho do processo de biodessulfatação. As principais rotas de utilização de substratos orgânicos pelos microrganismos foram identificadas por meio de modelação cinética. A comunidade microbiana foi avaliada por hibridação in situ com fluorescência (FISH). Após o processo de biodessulfatação, avaliou-se o processo de oxidação parcial do sulfeto, em reator aeróbio operado em bateladas seqüenciais, com biomassa imobilizada em PU. Concluiu-se por FISH que as características intrínsecas dos materiais suportes influenciam o equilíbrio microbiano. A relação DQO/['SO IND.4'POT.2-'] igual a 1,3 representou a melhor condição para o processo de biodessulfatação, com PU e com CV como materiais suporte, com eficiência média em redução de sulfato igual a 96%. A adição de etanol melhorou o processo de redução de sulfato. Sulfeto gerado no processo de biodessulfatação foi oxidado parcialmente a enxofre elementar, com eficiência de remoção de 80% no reator aeróbio / In anaerobic biological systems for wastewater treatment well-designed sulphate can be reduced to sulfide by sulphate-reducing bacteria (SRB), and it can be subsequently oxidized to elemental sulphur, under low dissolved oxygen concentration ('< OU =' 0.1 mg/L). The present thesis evaluates the microbial sulphate reduction process in anaerobic sequencing batch biofilm reactors with immobilized biomass in polyurethane foam (PU) and vegetable coal (CV). Such support materials were previously selected by microbial adhesion tests executed in differential reactors. Afterwards, the effect of ethanol addition on the performance of sulphate reduction process was assessed. The main metabolic pathways of organic substrate utilization by microorganisms were identified by kinectic modelation. The microbial community was evaluated by fluorescence in situ hybridization (FISH). The partial sulfide oxidation process was also evaluated in aerobic sequencing batch reactor containing biomass immobilized in PU matrices. It was concluded by FISH that characteristics of the support materials has influence on the microbial equilibrium. The COD/['SO IND.4'POT.2-'] ratio equal to 1.3 provided the best condition for microbial sulphate reduction process in both reactors with mean efficience of 96%. The ethanol addition improved the sulphate reducing process. The sulfide generated was partialy oxidized to elemental sulphur in the aerobic reactor with removal efficience of 80%

The energy supplies of modern society seem to be necessarily associated with risks. In this paper, we address the question as to whether the efficient utilisation of energy in biological systems is also coupled to hazards. Most organisms oxidise highly reduced substrates with molecular oxygen in order to gain energy. In eukaryotes, this process takes place at the inner membrane of specialised organelles, the mitochondria. Interestingly, about 1% of the consumed oxygen molecules are reduced not to water, but to ROS (reactive oxygen species), which are deleterious to many macromolecules, including mitochondrial DNA. As a result, mitochondrial DNA mutations accumulate, in turn affecting the energy supply and inducing degeneration and ageing. / Nach dem heutigen Stand der Technik scheint eine ausreichende Energieversorgung der Gesellschaft stets mit Risiken verbunden zu sein. Wir gehen in dem Artikel der Frage nach, ob auch biologische Systeme bei der Nutzung von Energie Risiken in Kauf nehmen. Zur effizienten Energiegewinnung nutzen Organismen meist Sauerstoff zur Oxidation energiereicher Substrate. In Eukaryonten erfolgt die Energiegewinnung vor allem an der inneren Membran von Mitochondrien. Etwa 1 % des verbrauchten Sauerstoffs wird dabei nicht zu Wasser, sondern zu ROS (reactive oxygen species, reaktive Sauerstoffspezies) reduziert, die unter anderem die mitochondriale DNA schädigen und Mutationen hervorrufen. Diese akkumulieren auf Dauer und führen zu einer Störung der Energiegewinnung, in deren Folge Degenerations- und Alterungsphänomene auftreten.

M. Tech. (Department of Civil Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / Over time, the quality standard of stormwater in the City of Ekurhuleni (CoE) has deteriorated due to industrial, commercial, residential and farming activities. Stormwater quality directly impacts the treatment chain of potable water, and therefore, it should be kept in check at all stages. Innovations in the biofiltration process can provide useful, practical solutions to overcome crucial stormwater pollution problems. In 2013, the CoE developed stormwater design guidelines and standards to be implemented for the design of stormwater management, which include the principles of Water Sensitive Urban Design (WSUD) and Sustainable Urban Drainage Systems (SuDS) in particular. The CoE stormwater design guidelines and standards do not provide details on how the city plans to implement SuDS treatment trains to reduce stormwater pollution experienced by the city. This study aimed to verify the efficiency and effectiveness of vegetated biofilters on the stormwater treatment using CoE – Olifantsfontain's natural stormwater and to determine the most suitable vegetation to be used in the region. The CoE experimental case study was conducted to assess the efficiency of selected vegetated biofilters in lowering the concentration of orthophosphate (PO4-3), ammonium (NH4+), and nitrate (NO3-) from Tembisa/Olifantsfontain stormwater. In the experimental setup, six selected plant species were planted into 30 vegetated biofilter columns, namely: Agapanthus praecox (Dryland plant), Carpobrotus edulis (Dryland plant), Stenotaphrum secundatum (Dryland plant), Zantedeschia aethiopica (Wetland plant), Typha capensis (Wetland plant) and Phragmites australis (Wetland plant). The six species were grouped according to general habitats, i.e. three wetland and three dryland plants. Wetland plants were planted into fifteen vegetated biofilters, and dryland plants were also planted on another fifteen vegetated biofilters. The biofilters contained layers of sandy loam soil, coarse and and gravel sand. Each biofilter had a designated inlet and outlet section fitted with a gate valve to control retention time. The raw stormwater consisting of natural nutrient pollutants was applied to each vegetated biofilter through the inlet section. The samples were collected from the inlet and outlet of the six grouped vegetated biofilters during the month of June. All six plant species reduced outflow concentrations of PO4-3 and NH4+ by an average of 99% and 98%, respectively. The results also show that all plant species excluding Phragmites australis were able to reduce NO3- with outflow concentrations being reduced by an average of 58%. From the results obtained, it may be concluded that all the six plant species may be suitable variants to be applied as biofilter material for the purposes of treating urban stormwater in the CoE. The reason is that the determined removal efficiencies for bio-retention fall within 50% – 60% for PO4-3, and 40% - 50% for NH4+ and NO3- respectively. The results also show that if the plant species were applied for SuDs in the CoE, there could be a great improvement in the urban stormwater quality with the consequent improvement in both surface and groundwater quality of the receiving water bodies in the area. Regardless of the nutrient removal by selected plant species, the inclusion of vegetation in a field setting would slow flow rates and thus encourage infiltration into the soil, improve water quality, and support urban biodiversity. In the CoE, all the selected species could be used in the SuDS treatment trains targeting PO4-3, NH4+ and/or NO3-. The case study results provide a informed records for the CoE in the future/intended application SuDs in the upgrade/rehabilitation of its stormwater system.

Chitin in shrimp waste is tightly associated with proteins, lipids, pigments and mineral deposits. Therefore, these source materials have to be pretreated to remove these components. For a long time, chemical process has been used widely for extraction of chitin from shrimp waste. The chemical process however led to severe environmental damage and low chitin quality. The biological process has been shown promising to replace the harsh chemical process to reduce the environment impact. In our previous study chitin recovery from sterilized shrimp waste by Lactobacillus plantarum NCDN4 was investigated. However in large scale it is uneconomical to sterilize the shrimp waste. For that reason, in this study the microbial process using Lactobacillus plantarum NCDN4 for chitin recovery from unsterilezed shrimp waste has been investigated. Factors affecting the demineralization by this strain such as inoculum size, glucose concentration, initial pH, NaCl concentration and fermentation time were investigated. It was found that when unsterilized shrimp waste fermented with 20% L. plantarum inoculum, 12,5% glucose, and pH 6 for 4 days at 30oC, 99. 28% emineralization and 48.65% deproteination could be achieved. The ash and protein content of fermented residues were 1.33% and 22.46% respectively. Compared to sterilized condition the efficiency of demineralization and deproteination was similar. / Chitin trong phế liệu tôm liên kết chặt chẽ với protein, sắc tố và khoáng. Do vậy để thu được chitin cần có các bước tiền xử lí để loại các thành phần không phải chitin ra. Phương pháp hóa học được sử dụng rộng rãi từ lâu để tiền xử lí chitin. Tuy nhiên do phương pháp hóa học gây hại cho môi trường và tạo ra chitin chất lượng thấp, các nhà khoa học nỗ lực nghiên cứu tìm ra các phương pháp thay thế. Phương pháp sinh học được xem là rất khả quan để thay thế phương pháp hóa học. Trong nghiên cứu trước của chúng tôi, quá trình lên men phế liệu tôm thanh trùng bằng Lactobacillus plantarum NCDN4 đã được nghiên cứu. Tuy nhiên việc thanh trùng phế liệu tôm không kinh tế. Trong nghiên cứu này quá trình lên men phế liệu tôm không thanh trùng bằng Lactobacillus plantarum NCDN4 đã được khảo sát. Các yếu tố như tỷ lệ giống, nồng độ đường glucose, nồng độ NaCl, pH ban đầu của môi trường lên men và thời gian lên men đã được nghiên cứu. Kết quả cho thấy ở điều kiện 20% giống theo thể tích, 12,5% dịch đường glucose, 2% muối theo khối lượng, pH ban đầu 6, sau 5 ngày lên men lượng khoáng và protein trong nguyên liệu giảm tương ứng 99.28% và 48.65%. Lượng khoáng và protein còn lại tương ứng 1.33% và 22.46% (tính theo trọng lượng khô). So với phế liệu tôm không thanh trùng, hiệu quả loại khoáng và protein là tương đương.