A detailed study has been carried out to demonstrate the importance of external and internal mass transfer on the nitrification rates in three distinct treatment processes: flocculent and granular activated sludge, and suspended carrier reactor (SCR) systems. The major emphasis was on external mass transfer, and the impact of system hydrodynamics on this mechanism. Laboratory-scale flocculent and granular sequencing batch reactors were operated for the nitrification of a synthetic wastewater. A two-stage, continuous, nitrifying SCR was operated using the same wastewater feed. Within each stage, biofilm was grown on two types of commercial carriers- the Natrix C10/10 from ANOX AB (Sweden); and the K1 carrier from Kaldnes Miljøteknologi (Norway). Biofilm carriers obtained from each of these reactors was utilised for the mass transfer investigations. The major findings, and contributions of the work to the field of biological wastewater treatment, are described in the following paragraphs. In order to complete the work, a novel experimental tool, the TOGA (Titrimetric and Off-Gas Analysis) sensor was created, which utilises off-gas mass balancing, coupled with pH titration to provide detailed measurement of biological reaction rates. An original method for off-gas mass balancing was developed, within a reactor that allowed modification of the hydrodynamic conditions using gas phase mixing independent of dissolved oxygen control within the liquid phase. This sensor has already proven to be a highly effective tool not only for the measurement of oxygen but also for carbon dioxide and various nitrogen species, and has application for numerous other compounds present in the gas phase of biological reactors (e.g. hydrogen, methane). The application of the TOGA sensor signals to the nitrification process was demonstrated, which enabled the online measurement of oxygen, ammonia, and nitrite reaction rates. The TOGA sensor development underpinned the majority of the subsequent experimental work within this thesis. Dissolved oxygen microelectrodes were also used, enabling microscale measurements to be made in conjunction with the macroscale TOGA sensor analyses. Combined with size and microbiological analyses a detailed study of mass transfer and reaction was able to be carried out on the various systems. For suspended aggregate systems (flocs and granules): A spherical particle model was developed and used to predict the potential for external mass transfer limitation in flocs and granules. The significance of this limitation was confirmed experimentally, by observing changes in reaction rate or concentration boundary layer (in the TOGA sensor or microelectrode study, respectively) upon modification of the system’s flow conditions. Despite this flow effect being small, and only observable under low bulk liquid substrate concentrations, the external mass transfer limitation was concluded to be significant for biological flocs and granules even at higher substrate concentrations. As particle size and the maximum volumetric reaction rate of the biomass increases, external mass transfer effects become increasingly significant. The work highlights the impact of mass transfer limitation on the measurement of Monod half saturation coefficients (KS) in flocs and granules. Without accounting for external or internal mass transfer limitation, KS is seriously overestimated and becomes a lumped parameter, reflecting not only the microbial response but also the mass transfer limitations observed within the system under study. To avoid confusion or generation of erroneous results, care should be taken in defining, measuring and utilising the half saturation coefficient in biological systems where the biomass is not present as individual cells or extremely small flocs. For Suspended Carrier Reactor systems: External and internal mass transfer are both concluded to be important rate limiting steps within suspended carrier reactors. The demonstration of a significant impact of fluid flow conditions on the nitrification rates highlights the impact of external mass transfer limitation within these systems. Application of a one-dimensional biofilm model to the experimental results led to the conclusion that there is little difference between the external mass transfer limitation of the two different carrier types, for carriers grown under the same environmental conditions. However, there was a significantly higher areal nitrification rate observed on the Natrix carriers compared to the Kaldnes carriers. It is the biofilm structure that is critically important in characterising the mass transfer steps. Systems operated under high nitrogen loads, producing filamentous biofilms on the carrier surface, were found to have larger external mass transfer coefficients and responses to changes in fluid flow than those carriers which were operated under nitrogen-limited conditions (producing a flatter, more gel-like biofilm). The structure of the biofilm colonising the carrier surface was far more important in defining the mass transfer coefficient than the actual carrier type used. In a remarkably similar trend to that of the external mass transfer coefficient, the biofilm morphology was again significantly more important than carrier type in determining both the magnitude and response to fluid flow of the gas-liquid mass transfer coefficient for oxygen (kLa) calculated within the laboratory TOGA sensor. These findings led to the postulation that direct gas-biofilm interfacial mass transfer mechanism is occurring within the SCR systems. This hypothesis is an alternative to the standard mechanism of gas transfer from the bubble into the liquid phase, and then into the biofilm. Understanding of interfacial transfer is likely to be important for developing the knowledge of SCR processes. Overall, both external and internal mass transfer phenomena have been demonstrated to create important rate limitations to suspended aggregate systems (flocs and granules) and biofilms grown in suspended carrier reactors. This significantly advances the conceptual understanding of these biological treatment processes.

A detailed study has been carried out to demonstrate the importance of external and internal mass transfer on the nitrification rates in three distinct treatment processes: flocculent and granular activated sludge, and suspended carrier reactor (SCR) systems. The major emphasis was on external mass transfer, and the impact of system hydrodynamics on this mechanism. Laboratory-scale flocculent and granular sequencing batch reactors were operated for the nitrification of a synthetic wastewater. A two-stage, continuous, nitrifying SCR was operated using the same wastewater feed. Within each stage, biofilm was grown on two types of commercial carriers- the Natrix C10/10 from ANOX AB (Sweden); and the K1 carrier from Kaldnes Miljøteknologi (Norway). Biofilm carriers obtained from each of these reactors was utilised for the mass transfer investigations. The major findings, and contributions of the work to the field of biological wastewater treatment, are described in the following paragraphs. In order to complete the work, a novel experimental tool, the TOGA (Titrimetric and Off-Gas Analysis) sensor was created, which utilises off-gas mass balancing, coupled with pH titration to provide detailed measurement of biological reaction rates. An original method for off-gas mass balancing was developed, within a reactor that allowed modification of the hydrodynamic conditions using gas phase mixing independent of dissolved oxygen control within the liquid phase. This sensor has already proven to be a highly effective tool not only for the measurement of oxygen but also for carbon dioxide and various nitrogen species, and has application for numerous other compounds present in the gas phase of biological reactors (e.g. hydrogen, methane). The application of the TOGA sensor signals to the nitrification process was demonstrated, which enabled the online measurement of oxygen, ammonia, and nitrite reaction rates. The TOGA sensor development underpinned the majority of the subsequent experimental work within this thesis. Dissolved oxygen microelectrodes were also used, enabling microscale measurements to be made in conjunction with the macroscale TOGA sensor analyses. Combined with size and microbiological analyses a detailed study of mass transfer and reaction was able to be carried out on the various systems. For suspended aggregate systems (flocs and granules): A spherical particle model was developed and used to predict the potential for external mass transfer limitation in flocs and granules. The significance of this limitation was confirmed experimentally, by observing changes in reaction rate or concentration boundary layer (in the TOGA sensor or microelectrode study, respectively) upon modification of the system’s flow conditions. Despite this flow effect being small, and only observable under low bulk liquid substrate concentrations, the external mass transfer limitation was concluded to be significant for biological flocs and granules even at higher substrate concentrations. As particle size and the maximum volumetric reaction rate of the biomass increases, external mass transfer effects become increasingly significant. The work highlights the impact of mass transfer limitation on the measurement of Monod half saturation coefficients (KS) in flocs and granules. Without accounting for external or internal mass transfer limitation, KS is seriously overestimated and becomes a lumped parameter, reflecting not only the microbial response but also the mass transfer limitations observed within the system under study. To avoid confusion or generation of erroneous results, care should be taken in defining, measuring and utilising the half saturation coefficient in biological systems where the biomass is not present as individual cells or extremely small flocs. For Suspended Carrier Reactor systems: External and internal mass transfer are both concluded to be important rate limiting steps within suspended carrier reactors. The demonstration of a significant impact of fluid flow conditions on the nitrification rates highlights the impact of external mass transfer limitation within these systems. Application of a one-dimensional biofilm model to the experimental results led to the conclusion that there is little difference between the external mass transfer limitation of the two different carrier types, for carriers grown under the same environmental conditions. However, there was a significantly higher areal nitrification rate observed on the Natrix carriers compared to the Kaldnes carriers. It is the biofilm structure that is critically important in characterising the mass transfer steps. Systems operated under high nitrogen loads, producing filamentous biofilms on the carrier surface, were found to have larger external mass transfer coefficients and responses to changes in fluid flow than those carriers which were operated under nitrogen-limited conditions (producing a flatter, more gel-like biofilm). The structure of the biofilm colonising the carrier surface was far more important in defining the mass transfer coefficient than the actual carrier type used. In a remarkably similar trend to that of the external mass transfer coefficient, the biofilm morphology was again significantly more important than carrier type in determining both the magnitude and response to fluid flow of the gas-liquid mass transfer coefficient for oxygen (kLa) calculated within the laboratory TOGA sensor. These findings led to the postulation that direct gas-biofilm interfacial mass transfer mechanism is occurring within the SCR systems. This hypothesis is an alternative to the standard mechanism of gas transfer from the bubble into the liquid phase, and then into the biofilm. Understanding of interfacial transfer is likely to be important for developing the knowledge of SCR processes. Overall, both external and internal mass transfer phenomena have been demonstrated to create important rate limitations to suspended aggregate systems (flocs and granules) and biofilms grown in suspended carrier reactors. This significantly advances the conceptual understanding of these biological treatment processes.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.

Thesis (Ph. D.)--Stanford University, 1998. / Includes bibliographical references (leaves 349-357).

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The maize (Zea mays L.) stands out among the great cultures of global economic importance. In Brazil presents itself as the third most cultivated cereal, because its use ranging from animal feed to high-tech industries. However, productivity is still low or suffers fluctuations due to poor distribution of rainfall. As the drought caused by lack of water, the main production factor affecting the productivity of this crop in the main producing regions of the country. What, for RS West Frontier region is no different. Thus, the use of supplemental irrigation presents itself as a fundamental alternative to minimize the effect of water stress and increase productivity. Another limiting factor is the adequacy of plant density in scenarios with the use of supplemental irrigation. The purpose of the present study was to asses the effect of different irrigation strategies and plant densities on the yield components of maize crop cultivated in second season. This work took place at Instituto Federal Farroupilha - Alegrete Campus/RS, from January to June 2014. The treatments were arranged in a randomized disign in a factorial scheme 4x5 with 3 replications. The moment of irrigation was defined in turn fixed irrigation of five days and the amount of water applied, based on evapotranspiration of culture (Etc). The treatments were 0% (rainfall without irrigation), 50%, 75%, 100% and 125% of the Etc was set four densities of plants (40, 70, 100 and 130 thousand plants.ha-1). It was assessed: Plant height, ear insertion height, stem diameter, leaf area index, dry matter of the aerial part, ear length, ear diameter, number of corn ear per plant, number of grains per ear, aboveground dry matter, mass of 100 grains, harvest index and grain productivity and efficient use of water. There was a population of plants that maximized the yield of corn for each irrigation strategies adopted. The different irrigation strategies influenced mainly the stem diameter, leaf area index, dry matter of the shoot, the length of ear number of grains per ear, the mass of one hundred grains and grain productivity and efficient use of water. The use of supplementary irrigation is recommended to maximize the productivity of maize second crop to the border region west of the RS. The choice of the plant density is a crucial variable in the cultivation of maize crops, since the different populations significantly influenced the components of yeld. Furthermore, there is a plant density which maximizes the yield of corn grain for each blade irrigation adopted. The combination which obtained greater grain productivity was 130 thousand plants.ha-1 with the strategies 100% of irrigation Etc (15.25 t. ha-1). / A cultura do milho (Zea mays L.) destaca-se entre as grandes culturas de importância econômica mundial. No Brasil apresenta-se como o terceiro cereal mais cultivado, devido sua utilização que vai desde a alimentação animal até indústrias de alta tecnologia. Porém, a produtividade ainda é baixa ou sofre flutuações devido a má distribuição das chuvas. Sendo o déficit hídrico causado pela falta da água, o principal fator de produção que afeta a produtividade dessa cultura nas principais regiões produtoras do País. O que, para a região Fronteira Oeste do RS não é diferente. Assim, a utilização de irrigação suplementar apresenta-se como alternativa fundamental para minimizar o efeito do déficit hídrico e aumentar a produtividade. Outro fator limitante é a adequação da densidade de plantas em cenários com utilização de irrigação suplementar. Neste sentido, o objetivo do presente estudo foi avaliar o efeito de diferentes lâminas de irrigação e densidades de plantas sobre os componentes de crescimento, desenvolvimento e rendimento da cultura do milho safrinha, cultivado na região Fronteira Oeste do Estado do RS. O trabalho foi conduzido no Instituto Federal Farroupilha Campus de Alegrete/RS, no período de janeiro a maio de 2014. Utilizou-se o híbrido superprecoce Dekalb 250 VT Pro2. Os tratamentos foram dispostos em um Delineamento Inteiramente Casualizado em esquema fatorial 4x5 com três repetições. O momento das irrigações foi definido em turno de rega fixo de cinco dias e a quantidade de água aplicada, com base na evapotranspiração da cultura (Etc) medidas através de um tanque classe A e ajustadas conforme os coeficientes de tanque e de cultivo. Os tratamentos foram: 0% (precipitação pluviométrica), 50%, 75%, 100% e 125% da Etc. Foram definidas quatro densidades de plantas (40, 70, 100 e 130 mil plantas.ha-1). Avaliou-se: altura de plantas, altura de inserção de espiga, diâmetro de colmo, índice de área foliar, matéria seca da parte aérea, comprimento de espiga, diâmetro de espiga, número de espigas por planta, número de grãos por espiga, massa de cem grãos, índice de colheita, produtividade de grãos e eficiência no uso da água. As diferentes lâminas de irrigação influenciaram o diâmetro de colmo, o índice de área foliar, a matéria seca da parte aérea, o comprimento de espigas, o número de grãos por espigas, a massa de cem grãos, a produtividade de grãos e a eficiência no uso da água. A utilização de irrigação suplementar é recomendada para maximizar a produtividade do milho safrinha para a região fronteira oeste do RS. A escolha da densidade de plantas é uma variável decisiva no cultivo de milho safrinha, visto que, as diferentes densidades de planta influenciaram significativamente os componentes produtivos da cultura. Além disso, há uma densidade de plantas que maximiza o rendimento de grãos de milho para cada lâmina de irrigação adotada. A combinação que obteve maior produtividade de grãos foi na densidade de 130 mil plantas.ha-1 com a lâmina de irrigação de 100% da Etc com 15,25 t.ha-1.

Made available in DSpace on 2016-06-02T20:39:16Z (GMT). No. of bitstreams: 1 4764.pdf: 1247781 bytes, checksum: 31d3eab8632bf51e154f8ddd4fe82a96 (MD5) Previous issue date: 2012-11-19 / Universidade Federal de Minas Gerais / This dissertation addresses the forms of acting of local government in water governance, presenting the case of the Basin Committee Tietê-Jacaré, located in the central region of São Paulo State. The river basin committees are decentralized bodies that aim to discuss and decide the ways in which water resources should be managed at the local level. The new form of governance of water includes several local stakeholders involved in its use, as sectors of civil society and municipalities in the region of the basin. Through a sociological perspective, the main objective is to understand the dynamics of representation and participation of stakeholders within the Basin Committee, focusing on municipal governments. The Committee is understood here as an expression of social space where different agents are present with different social positions and try to impose their world view for all who are present. Therefore, it is important to consider the construction of hierarchies and relations of interdependence involving the main groups active in this space. / Esta dissertação trata das formas de atuação do poder público local na governança da água, apresentando o caso da Bacia Hidrográfica do Tietê- Jacaré, localizado na região central do Estado de São Paulo. Os comitês de bacias hidrográficas são instâncias descentralizadas que têm objetivo de discutir e decidir as formas como os recursos hídricos devem ser geridos em escala local. A nova forma de governança das águas compreende diversos agentes locais envolvidos no seu uso, como setores da sociedade civil e das prefeituras da região da bacia. Através de uma perspectiva sociológica, o objetivo central é compreender a dinâmica da representação e da participação dos agentes dentro do Comitê de Bacia, enfocando os poderes públicos municipais. O Comitê é entendido aqui como expressão do espaço social onde estão presentes diferentes agentes com diferentes posições sociais que tentam impor sua visão de mundo para todos os que estão presentes. Nesse sentido, é importante considerar a construção de hierarquias e as relações de interdependências envolvendo os principais grupos atuantes nesse espaço.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The Balfourodendron riedelianum of the family Rutaceae is a native forest species with timber value and is used in the manufacture of luxury furniture, construction, and so forth. Moreover, the species is suitable for medical use, insecticide, landscaping and recovery riparian areas. Despite the importance of this species, there are few studies in relation to seed technology, irrigation in the production of seedlings and field early growth. In this sense, species diaspores were collected in Palma Nova (RS), in the years of 2013 and 2015, and further processed and divided into samples for testing. The study was divided into three articles, in Article I – measurement of biometrics, pre-germination treatments and substrates for the germination of B. riedelianum diaspores; by using a sample of 2013 for physical characterization, through the weight of a thousand seeds (PMS), water content (TU) and biometrics, besides the germination test (G%) on different substrates after breaking dormancy. The dimensions of the B. riedelianum seeds had on average, 18.59; 9.03 and 9.38 mm in length; width and thickness, respectively. The dormancy was broken by immersion in cold water (8 ± 2 ° C) for 48 hours and germinating was conducted on vermiculite substrate. Article II – In the first, two experiments were carried out, the quality of the seeds collected in 2013, which have been stored for two years in cold and humid chamber was evaluated and sampled for TU testing, G% and sanity, and the second evaluated in the lot collected in 2015 the disinfestation of the seeds in the incidence of fungi and germination. Diaspores of B. riedelianum remained viable for 12 months under storage conditions, and disinfection with Orthocide® is indicated in order that provided high G% and IVG. The genus Aspergillus sp., Fusarium sp., Cladosporium sp. and Penicillium sp. were detected in both experiments. Article III - identified water depth required to optimize the growth of seedlings of B. riedelianum, and evaluated its initial field growth. Combinations were used of heads between 4, 8 and 12 mm day-1, after 180 days of water management application survival evaluation were performed, height, stem diameter, dry mass air, root dry weight and quality index Dickson. The treatments described in the vivarium were conducted in the field, wich 450 days after plantating were evaluated in relation to H, DC, MSA, leaf area and root length, chlorophyll content and chlorophyll a fluorescence. The head influenced the growth of seedlings of B. riedelianum, in the vivarium stage, which was confirmed in the field. Seedlings of Balfourodendron riedelianum can be produced initially with water depth of 4 mm day-1, which must be switched to 12 mm day -1after 60 days and remain so until the end of production. / Balfourodendron riedelianum da família Rutaceae é uma espécie florestal nativa com valor madeireiro, sendo utilizada na fabricação de móveis de luxo, construção civil, entre outros. Além disso, a espécie é indicada para uso medicinal, inseticida, paisagismo e recuperação de áreas ripárias. Apesar da importância desta espécie, há escassez de estudos em relação à tecnologia de sementes, à irrigação na produção de mudas e crescimento inicial a campo. Nesse sentido, foram coletados diásporos da espécie em Nova Palma (RS), em 2013 e 2015, após beneficiados e divididos em amostras para a realização dos testes. O estudo foi dividido em três capítulos, no Capítulo I - foi mensurado a biometria, tratamentos pré-germinativos e substratos para germinação de diásporos de B. riedelianum; sendo utilizado uma amostra do lote de 2013 para caracterização física, por meio do peso de mil sementes (PMS), teor de água (TU) e biometria, além do teste de germinação (G%) em diferentes substratos após superação da dormência. As dimensões dos diásporos de B. riedelianum apresentam em média, 18,59; 9,03 e 9,38 mm de comprimento; largura e espessura, respectivamente. A dormência foi superada pela imersão em água fria (8 ± 2 °C), por 48 horas e germinação pode ser conduzida em substrato vermiculita. No Capítulo II - foram realizados dois experimentos, no primeiro, foi avaliado a qualidade dos diásporos coletados em 2013 que foram armazenados durante dois anos em câmara fria e úmida, sendo retiradas amostras para testes de TU, G% e sanidade, no segundo foi avaliado no lote coletado em 2015 a desinfestação dos diásporos na incidência de fungos e na germinação. Os diásporos de B. riedelianum mantiveram-se viáveis durante 12 meses sob as condições de armazenamento, e a desinfestação com Orthocide® é indicado, tendo em vista, que proporcionou elevada G% e IVG. Os gêneros Aspergillus sp., Fusarium sp., Cladosporium sp. e Penicillium sp. foram detectados em ambos os experimentos. No Capítulo III – foi identificado a lâmina de irrigação necessária para otimizar o crescimento das mudas de B. riedelianum, e avaliado seu crescimento inicial a campo. Foram utilizados combinações entre as lâminas 4, 8 e 12 mm dia-1, que após 180 dias de aplicação do manejo hídrico realizou-se avaliações da sobrevivência (Sob), altura (H), diâmetro do coleto (DC), massa seca aérea (MSA), massa seca radicular (MSR) e índice de qualidade de Dickson (IQD). Os tratamentos descritos no experimento do viveiro foram conduzidos a campo, que aos 450 dias após o plantio foram avaliados em relação a H, DC, MSA, área foliar e comprimento radicular, teor de clorofila e fluorescência da clorofila a. As lâminas influenciaram no crescimento das mudas de B. riedelianum, na fase de viveiro, o que foi confirmado no campo. Mudas de Balfourodendron riedelianum podem ser produzidas, inicialmente, com lâmina de irrigação de 4 mm dia-1, a qual deve ser alternada para 12 mm dia-1 a partir dos 60 dias, permanecendo assim até o final da produção.

L'eau est un besoin vital pour l'Homme et chaque société se doit de la gérer au mieux pour subvenir à ce besoin élémentaire aujourd'hui et dans l'avenir. Les changements climatiques en cours et en particulier le réchauffement climatique influencent fortement les hydrosystèmes et les activités économiques de montagne forçant ces territoires à s'adapter à ces nouvelles conditions. Les choix de développement socio-économiques ont également une importance prépondérante dans l'émergence ou non de pénuries d'eau.Au cours de cette thèse un modèle couplant représentations des ressources naturelles et des activités socio-économiques a été construit. Il permet d'explorer à la fois les impacts sur la disponibilité des ressources en eau, des changements climatiques et des choix socio-économiques pour un territoire de montagne à différents horizons temporels. Toutes les combinaisons de scénarios climatiques et socio-économiques peuvent être expérimentées dans le modèle.La station de ski de Megève (France) a servi de terrain d'application pour le développement du modèle hydro-anthropique. Ce modèle devant servir comme aide à la décision pour la mise en place de politiques d'adaptation, la délicate question du transfert de connaissances entre Science et Société est interrogée. Via l'insertion du modèle scientifique développé dans des Serious-Games une proposition d'interface est réalisée. A travers le projet C3-Alps qui a financé cette thèse, d'autres transferts de connaissances pour l'adaptation aux changements climatiques dans les Alpes ont également été réalisés. / Water is a vital need for Human and each society have to manage it at best to meet this basic need today and in the future.Current climatic changes and especially global warming strongly impact hydrosystems and economical activities of mountainous areas, forcing these territories to adapt to these new conditions. Socio-economic development choices have also a great importance in water shortages occurrence. In this thesis a model coupling representations of water resources and and socio-economic activities was built.It allows to explore both climate change impacts and socio-economic choices impacts on water resources availability in a mountain territories at different time scales. All combinations of climate change and socio economic choices scenarios are testable.The Megève ski resort station in France was used to develop and apply the hydro-anthropic model. The latter must contribute, as a decision support tool, to climate change adaptation policies developpement. Therefore, the tricky question of knowledge transfer between Science and Society is addressed in this thesis. The scientific model developped was introduced in Serious-Games as an interface proposal. Through the C3-Alps projet which financed this thesis, others knowledge tranfers for climate change adapation in the Alps were also addressed.

This research has undertaken two key mandates. One was to develop modifications to the African Catchment Game (ACG), a role playing simulation game, in order to simulate rainfall and water management processes representative of the southern African context. The other was to understand what, if any, learning associated with water management issues had taken place as a result of playing the ACG. The modification process took the form of an action research process. The initial modifications were trialed with South African students as part of their undergraduate Geography course offered at Rhodes University, South Africa. Subsequent modifications were implemented over a five month period with three diverse participant groups, namely Finnish, American and South African participants. An interpretive research orientation was employed in order to analyse both the qualitative and quantitative data that was generated. Pre- and Post-Game Questionnaires were used in order to identify the learning and understanding which the participants constructed as a result of playing the ACG. The Chi-Square Test was also applied to each of the pre- and post- questions to establish statistical significance. Subsequent analysis of these questions identified and traced patters and trends associated with learning and understanding across the three game runs. This research study draws on social constructivism and experiential learning as the dominant education theory that underpins it. Results revealed that for all three game runs learning took place. Participants identified dominant themes and environmental dimensions both before and after playing the ACG. The analysis of these responses indicated a deeper awareness of water as a contributing factor for sustainable economic development while the game runs enabled the researcher to adjust the water availability within each game run until rainfall and water management processes representative of a southern African context were successfully simulated in the last game run.

Atualmente, a ciência econômica tem aplicado conceitos e teorias na questão ambiental para melhor utilização dos recursos naturais, visando ao desenvolvimento sustentável, ou seja, garantir que as futuras gerações igualmente possam dispor do meio ambiente. A economia possui ferramentas que podem ser utilizadas na gestão hídrica, para otimizar o uso da água e preservar o meio ambiente. A experiência internacional tem demonstrado a utilização de importantes instrumentos econômicos de políticas públicas para a gestão dos recursos hídricos, com inegável efetividade. O Estado de Roraima, localizado na Amazônia e com grande patrimônio ambiental e abundantes corpos de água, tem o dever de cuidar melhor de seus recursos naturais. Esta dissertação tem por objetivo analisar alguns instrumentos econômicos de políticas públicas, criados pela legislação federal e estadual, e aplicáveis ao Estado de Roraima. O método de estudo baseia-se em pesquisa bibliográfica e documental, abordando pesquisas empíricas sobre o tema. Conclui-se que, dos instrumentos disponíveis, apenas a outorga do direito de uso foi implementada, e os outros mecanismos, principalmente a cobrança pelo uso da água, tem sido negligenciado pelas políticas públicas estaduais. / Nowadays, economic science has applied concepts and theories in environmental issues for the better use of natural resources, aiming at sustainable development, i.e. ensuring that future generations can also have the environment. The economy has tools that can be used in water management to optimize water use and preserve the environment. International experience has demonstrated the important use of economic instruments of public policy for the management of water resources, with undeniable effectiveness. The Roraima State, located in the Amazon and with major environmental heritage and abundant water bodies, has a duty to take better care of their natural resources. This dissertation aims to analyze some economic instruments of public policy, created by federal and state laws, and applicable to the state of Roraima. The study method is based on documentary and bibliographical research, empirical research addressing the issue. We conclude that the instruments available, only granting the right of use was implemented, and other mechanisms, especially the charge for water use, has been neglected by the state public policies.