Estudos de novos sistemas de tratamento de águas residuais vêm crescendo mundialmente. Os esforços para avançar e aprofundar os conhecimentos sobre os processos de eliminação de impurezas da água em seu estado bruto natural, bem como para otimizar tecnológica e economicamente as operações envolvidas, são uma resposta ao desafio, cada vez mais premente, de proporcionar às populações urbanas e rurais a utilização em quantidades e qualidade adequadas deste recurso fundamental para a vida no planeta. Dentre os vários tipos de processos para a depuração das águas servidas, este estudo enfoca aspectos físicos dos sistemas conhecidos como wetlands e de uma determinada modalidade de reator biológico anaeróbio. Os sistemas conhecidos como wetlands, que são um aperfeiçoamento mais controlado de processos que existem na natureza, têm um papel de destaque na eliminação de impurezas transportadas por efluentes. Os reatores biológicos contemplados neste estudo são do tipo anaeróbio de fluxo ascendente, mais conhecidos pela sigla UASB correspondente às iniciais de sua designação em inglês (upflow anaerobic sludge blanket), que estão sendo cada vez mais utilizados para tratamento de efluentes urbanos. Eventualmente seus efluentes necessitam de tratamento posterior que será realizado nas wetlands. Todo processo tecnológico demanda constante aperfeiçoamento de seu desempenho. As melhorias são propostas com base na observação e avaliação do desempenho, dos sistemas de tratamento de água, que têm componentes físicoquímicas, biológicas e hidráulicas. O desempenho hidrodinâmico do reator (UASB) e da wetland plantada foram o objeto desse estudo. O objetivo foi utilizar a metodologia dos traçadores conjugada com as técnicas de análise de respostas a impulsos em sistemas. Foram empregados traçadores radioativos (bromo, tecnécio e trítio) e ativáveis (DOTAIn, DOTA-Eu, DTPA-In, DTPA-La, DTPA-Sm e DTPA-Eu) e seus resultados tratados e analisados por softwares apropriados. Os resultados indicaram que os traçadores ativáveis testados têm potencial para serem utilizados nos sistemas hidráulicos naturais ou artificiais. Palavras-chave: tratamento de águas residuárias, wetland, reator UASB, traçadores ativáveis. / Research and development of novel spent water treatment processes are increasing worldwide. A large amount of effort is directed towards the advancement and deepening of the knowledge concerning elimination of water contaminants, as well as optimization of the processes required to that end, both from the technological and the economic viewpoints. Such activities aim to meet the increasingly challenging need of providing water in large quantities and adequate qualities to urban and rural communities. Among the several processes presently available for the treatment of natural water resources, and especially for treatment of wastewater, the present study focused on systems known as wetlands and a special concept of biological reactor. It focuses in the selection of tracer techniques aiming at the observation and evaluation of the performances of such systems. Treatment in wetland systems constitute a reproduction at a more controlled level, of processes occurring in nature. They play an outstanding role in eliminating effluent-borne impurities and contaminants. The biological reactors assessed in this study are of the anaerobic type with upward internal flow. These are better known as UASB reactors, an acronym for upflow anaerobic sludge blanket, and are being increasingly employed in processing urban wastewater. Nonetheless, their effluent may eventually require a further polishing, which can achieved by flushing them through a wetland system. The performance of any technological process requires a continuous improvement. This improvement is based on the observation, measurement and evaluation of the state of art of the process. In the present study tracer techniques have been coupled with system impulse-response analysis methods. A novel kind of tracer, the activable tracer, was tested and assessed by comparison with radiotracer performance. The results obtained with both activable and radioactive tracers have been processed and analyzed by appropriate software.

<p>Coal provides for 77% of South Africa&rsquo / s primary energy needs and is therefore a major resource that supports the socio-economic needs of South African citizens. Power stations are the major consumers of coal in South Africa and produces electricity from burned coal. The burning of coal produces a large volume of ash that is disposed in the form of ash dump systems. The ash&nbsp / dump system is treated with high salinity process water from the power station for dust suppression. The process water contains salts due to evaporation processes from the recirculation&nbsp / &nbsp / of&nbsp / water in the cooling water system. Various studies to evaluate the sustainability of the ash dump system as a sustainable salt sink were therefore conducted. This study aimed to develop a conceptual model for the ash dump system by evaluating the movement of the process water trough the ash dump and the impacts it might have on the underlying weathered dolerite aquifer. This was achieved by evaluating the hydraulic and transport properties of the ash dump system. An initial site conceptual model was first established prior to the application of the hydraulic&nbsp / and transport methods. The initial conceptual model was based on the literature, previous reports and an initial site walk over. Known and tested hydraulic and transport methods were applied&nbsp / n bo.th field and laboratory scale for the saturated part of the ash dump system. The laboratory experiments comprised of column and core experiments. These methods assisted in&nbsp / parameter estimation of hydraulic and transport properties and also assisted in the planning of the field experiments. The field experiments were conducted in the form of slug tests, tracer&nbsp / dilution and natural gradient divergent tracer test experiments. The combined laboratory and field experiments provided statistically significant values that were then used as inputs into the&nbsp / conceptual model. Field experiments were also applied to a surrogate aquifer that represented the underlying shallow weathered dolerite aquifer of the ash dump system. The components of&nbsp / the updated conceptual model identified and investigated include the physical environment, the calculated hydraulic and transport properties.The ash dump can be conceptualized as a 20 to&nbsp / &nbsp / 30 meter high heap of consolidated clay size ash&nbsp / particles built on top of an underlying shallow weathered dolerite aquifer. The ash dup is directly connected to the underlying weathered&nbsp / dolerite aquifer. The saline water within the saturated zone has the ability to move through the ash dump system with hydraulic conductivities ranging between 10-1-10- 2 m/day, with flow&nbsp / velocities of 7-8m/day and effective porosities of 1%-2%. The hydraulic properties of the ash dump are, amongst others, controlled by the ash geology, contact time of the process water with the&nbsp / sh and show a significant reduction in hydraulic conductivity over time, before reaching a steady state. The transport properties are controlled by advection and spreading in available&nbsp / pathways. Results for the surrogate underlying fractured rock aquifer show flow velocities of 31m/day and an effective porosity of 1%.This suggests that the underlying weathered dolerite&nbsp / aquifer is vulnerable to process water contamination from the ash dump system. The study illustrates the importance of a site conceptual model before the application of investigative&nbsp / methods. Hence having a site conceptual model provides an excellent platform for hydraulic and transport estimation. The development of a site conceptual model enhanced the&nbsp / understanding of flow and transport movement of the processed&nbsp / water trough the ash dump, it also assisted as a beneficial tool to enhance ash dump management.</p>

<p>Coal provides for 77% of South Africa&rsquo / s primary energy needs and is therefore a major resource that supports the socio-economic needs of South African citizens. Power stations are the major consumers of coal in South Africa and produces electricity from burned coal. The burning of coal produces a large volume of ash that is disposed in the form of ash dump systems. The ash&nbsp / dump system is treated with high salinity process water from the power station for dust suppression. The process water contains salts due to evaporation processes from the recirculation&nbsp / &nbsp / of&nbsp / water in the cooling water system. Various studies to evaluate the sustainability of the ash dump system as a sustainable salt sink were therefore conducted. This study aimed to develop a conceptual model for the ash dump system by evaluating the movement of the process water trough the ash dump and the impacts it might have on the underlying weathered dolerite aquifer. This was achieved by evaluating the hydraulic and transport properties of the ash dump system. An initial site conceptual model was first established prior to the application of the hydraulic&nbsp / and transport methods. The initial conceptual model was based on the literature, previous reports and an initial site walk over. Known and tested hydraulic and transport methods were applied&nbsp / n bo.th field and laboratory scale for the saturated part of the ash dump system. The laboratory experiments comprised of column and core experiments. These methods assisted in&nbsp / parameter estimation of hydraulic and transport properties and also assisted in the planning of the field experiments. The field experiments were conducted in the form of slug tests, tracer&nbsp / dilution and natural gradient divergent tracer test experiments. The combined laboratory and field experiments provided statistically significant values that were then used as inputs into the&nbsp / conceptual model. Field experiments were also applied to a surrogate aquifer that represented the underlying shallow weathered dolerite aquifer of the ash dump system. The components of&nbsp / the updated conceptual model identified and investigated include the physical environment, the calculated hydraulic and transport properties.The ash dump can be conceptualized as a 20 to&nbsp / &nbsp / 30 meter high heap of consolidated clay size ash&nbsp / particles built on top of an underlying shallow weathered dolerite aquifer. The ash dup is directly connected to the underlying weathered&nbsp / dolerite aquifer. The saline water within the saturated zone has the ability to move through the ash dump system with hydraulic conductivities ranging between 10-1-10- 2 m/day, with flow&nbsp / velocities of 7-8m/day and effective porosities of 1%-2%. The hydraulic properties of the ash dump are, amongst others, controlled by the ash geology, contact time of the process water with the&nbsp / sh and show a significant reduction in hydraulic conductivity over time, before reaching a steady state. The transport properties are controlled by advection and spreading in available&nbsp / pathways. Results for the surrogate underlying fractured rock aquifer show flow velocities of 31m/day and an effective porosity of 1%.This suggests that the underlying weathered dolerite&nbsp / aquifer is vulnerable to process water contamination from the ash dump system. The study illustrates the importance of a site conceptual model before the application of investigative&nbsp / methods. Hence having a site conceptual model provides an excellent platform for hydraulic and transport estimation. The development of a site conceptual model enhanced the&nbsp / understanding of flow and transport movement of the processed&nbsp / water trough the ash dump, it also assisted as a beneficial tool to enhance ash dump management.</p>

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 3 uppsatser.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

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