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Design and evaluation of a cost effective household drinking water treatment systemMahlangu, Themba Oranso 20 August 2012 (has links)
M.Sc. / The world is focusing on increasing the number of people who have access to safe drinking water due to the ascending numbers of drinking water related illnesses reported annually in rural areas where water is not treated before consumption. To meet this goal, household water treatment has to be introduced especially in places where homes are wide apart making centralised water treatment improbable. Most readily available household water treatment systems (HWTS) such as membrane filters may not be affordable in rural areas due to power requirements and degree of ability to use and maintain them. This study was therefore aimed at designing and constructing HWTS using readily available material such as sand, gravel, zeolites and clays. Five HWTS were designed, built, evaluated and compared based on their ability to remove chemical contaminants such as iron, arsenic and fluorides from drinking water. The types of filters that were used during this study are the biosand filter (BSF), a modified biosand filter with zeolites (BSFZ), a silver impregnated porous pot (SIPP) filter, a ceramic candle filter (CCF) and a bucket filter (BF). Effectiveness of the filters in reducing physical parameters such as turbidity and visual colour was also assessed. The water treatment devices had the following flow rates; 1.74 L/h – 19.20 L/h (BSFZ), 0.81 L/h – 6.84 L/h (BSF), 0.05 L/h – 2.49 L/h (SIPP) and 1.00 L/h – 4.00 L/h (CCF). The flow rates were high at the early stages of filter use and decreased with increase in the volume of water filtered through. The flow rates of the filters were affected by the turbidity of intake water which was between 1.74 NTU – 42.93 NTU and correlated to chlorophyll a concentrations. The household water treatment technologies reduced turbidity to levels less than 1 NTU (> 90% reduction) in the following order SIPP > BSFZ > BSF > CCF > BF. The filters achieved greater than 60% retention of calcium, magnesium, iron and arsenic. These contaminants with the exception of arsenic were reduced to acceptable levels of the South African National Standard of drinking water (SANS 241, 2004). Compared to the other filters, the BSFZ performed better in removing nitrates, phosphates and fluorides although the overall retention efficiency was low. Total organic carbon was removed greatly by the CCF (39%) and the least removal was by the BF. The overall performance of the filters in reducing contaminants from drinking water was in the order BSFZ > BSF > SIPP > CCF > BF. Filter washing vi resulted in an overall increase in the flow rates of the filters but negatively affected turbidity reduction. The filters still removed contaminants after total cumulative volumes of 1200 L (BSFZ, BSF, CCF and BF) and 300 L (SIPP) were filtered through the devices. The five evaluated filters have several advantages to the readily available technologies and the advantages include ease of construction, operation and maintenance. The filters are gravity driven and work independent of temperature. These HWTS incorporate safe storages fitted with spigots to eliminate recontamination of water when it is drawn for use. The filters can produce enough drinking and cooking water for a family of six members due to their high flow rates. The BSFZ, BSF, SIPP, CCF and BF may therefore be considered for treating contaminated water at household scale in places where water is taken directly from the source without treatment.
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Ocorrência e remoção de contaminantes emergentes por tratamentos convencionais de água e esgoto / Occurrence and removal of emerging contaminants by conventional water and wastewater treatmentsPescara, Igor Cardoso, 1983- 26 August 2018 (has links)
Orientador: Wilson de Figueiredo Jardim / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-26T13:39:08Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014 / Resumo: Este trabalho teve como objetivo avaliar a eficiência dos tratamentos empregados em cinco estações de tratamento de esgoto (ETE) e duas estações de tratamento de água (ETA) na remoção dos hormônios endógenos estrona (E1), 17?-estradiol (E2), estriol (E3), testosterona (TTN) e progesterona (PROG), hormônios sintéticos 17a-etinilestradiol (EE2), dietilestilbestrol (DES), norgestrel (NGT) e mestranol (MEE), produtos de uso industrial bisfenol A (BPA), fenolftaleína (PhPh), n-nonilfenol (nNP), n-octilfenol (nOP) e triclosan (TCS), o fármaco cafeína (CAF) e o pesticida atrazina (ATZ). Foi possível quantificar BPA, E1, E3, CAF e ATZ em esgoto bruto e BPA, E1, CAF e ATZ em água bruta. Para cada composto, tanto os tratamentos realizados pelas ETE quanto os realizados pelas ETA apresentaram eficiências de remoção variáveis. A cafeína foi o composto-alvo mais frequentemente encontrado nas amostras, sendo escolhida como indicador químico para avaliar a eficiência dos tratamentos. Foi encontrada uma taxa média de 99% para a remoção de CAF pelas ETE, sendo as etapas com tratamentos biológicos as mais eficientes. Os tratamentos anaeróbios apresentaram remoções médias superiores a 80% na remoção de CAF, e os tratamentos aeróbios foram capazes de remover cerca de 20% da carga do composto. Nas ETE, os tratamentos de coagulação e desinfecção foram pouco eficientes nas remoções dos compostos-alvo. Já para as ETA, foram observadas remoções de até 80% de CAF pelos tratamentos empregados, sendo a etapa de coagulação a responsável pela maior remoção de CAF da água bruta. A etapa de filtração em carvão ativado apresentou eficiências de remoção menores que 10%, enquanto a desinfecção demonstrou baixa eficiência na remoção de CAF. Na cidade de São José do Rio Preto ¿ SP foi possível quantificar, ao menos uma vez, BPA, E1, E3, PhPh, CAF, TCS e ATZ em água superficial, BPA, TCS e CAF em água subterrânea e BPA, CAF e ATZ em água de abastecimento. / Abstract: Water and wastewater conventional treatments are often considered inefficient to remove micropollutants. The aim of this work was to evaluate the removal efficiency of the endogenous hormones estrone (E1), 17? estradiol (E2), estriol (E3), testosterone (TTN), and progesterone (PROG), the synthetic hormones 17a-ethinylestradiol (EE2), diethylstilbestrol (DES), norgestrel (NGT), and mestranol (MEE), the industrial chemicals bisphenol A (BPA), phenolphthalein (PhPh), n nonylphenol (nNP), n octylphenol (nOP), and triclosan (TCS), the pharmaceutical caffeine (CAF), and the pesticide atrazine (ATZ) by five wastewater treatment plants (WWTP) and two drinking water treatment plants (DWTP). The target compounds BPA, E1, E3, CAF, and ATZ were found in raw sewage, while BPA, E1, CAF, and ATZ in raw water. Both WWTP and DWTP treatments presented variable removal efficiency. Caffeine was the target compound more often detected in samples, thus it was chosen as a chemical indicator to evaluate treatment efficiencies. The average removal of CAF by WWTP was 99%, in which the biological treatment was more efficient. The anaerobic treatment presented an average removal of CAF above 80%, and around 20% for the aerobic treatments. Coagulation and disinfection treatments of WWTP showed low efficiency to remove the target compounds. DWTP treatment efficiency reached up to 80% removal, with coagulation step presenting highest removals of CAF. The activated carbon filtration showed removal efficiency under 10%, whereas the disinfection step presented low efficiency to remove CAF. At São José do Rio Preto city were found, at least once, BPA, E1, E3, PhPh, CAF, TCS, and ATZ in surface water; BPA, TCS, and CAF in groundwater, and BPA, CAF, and ATZ in drinking water / Doutorado / Quimica Analitica / Doutor em Ciências
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Evaluating the impact of asset management in the water industry : a case study of East Rand Water Care Company (ERWAT)Mhlongo, Thabani 04 1900 (has links)
Thesis (MPA)--Stellenbosch University, 2014. / The asset management process and strategy has been adopted and implemented within the
public sector. Although the National Treasury developed the Capital Asset Management
Guidelines to assist with the development and implementation of the asset management
system the guidelines have received very little attention over the years. The Auditor
General’s findings indicate a lack of proper implementation of the asset management process.
The study provides a clear indication of the implementation of the asset management process
by most government entities, local government municipalities and the public sector.
The outcome is that while most entities have made progress with regards to the implementation,
much remains to be done. Most entities implement the asset management process
selectively. This does not yield positive and sustainable results and they end up abandoning
the whole asset management system. The report provides the process of successful development and implementation of asset
management, it also indicate that if there are element that are missed or not properly done
the process will not yield constant results or performance and the impact on the organization
performance will not be positive. The management of the organization must ensure
that asset management is aligned with strategic objectives of the organization and performance
measurement must be directly linked with asset management, performance measurement
should be used to determine progress and implementation. Service level agreements
must be established between all relevant departments including the finance department
and there must be agreement on the objectives between all stakeholders. The key to
proper implementation is the alignment of the asset management process with the strategic
objectives of the organization.
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Evaluation of seasonal impacts on nitrifiers and nitrification performance of a full-scale activated sludge systemAwolusi, Oluyemi Olatunji January 2016 (has links)
Submitted in complete fulfillment for the degree of Doctor of Philosophy (Biotechnology), Durban University of Technology, Durban, South Africa, 2016. / Seasonal nitrification breakdown is a major problem in wastewater treatment plants which makes it difficult for the plant operators to meet discharge limits. The present study focused on understanding the seasonal impact of environmental and operational parameters on nitrifiers and nitrification, in a biological nutrient removal wastewater treatment works situated in the midlands of KwaZulu Natal.
Composite sludge samples (from the aeration tank), influent and effluent water samples were collected twice a month for 237 days. A combination of fluorescent in-situ hybridization, polymerase chain reaction (PCR)-clone library, quantitative polymerase chain reaction (qPCR) were employed for characterizing and quantifying the dominant nitrifiers in the plant. In order to have more insight into the activated sludge community structure, pyrosequencing was used in profiling the amoA locus of ammonia oxidizing bacteria (AOB) community whilst Illumina sequencing was used in characterising the plant’s total bacterial community. The nonlinear effect of operating parameters and environmental conditions on nitrification was also investigated using an adaptive neuro-fuzzy inference system (ANFIS), Pearson’s correlation coefficient and quadratic models.
The plant operated with higher MLSS of 6157±783 mg/L during the first phase (winter) whilst it was 4728±1282 mg/L in summer. The temperature recorded in the aeration tanks ranged from 14.2oC to 25.1oC during the period. The average ammonia removal during winter was 60.0±18% whereas it was 83±13% during summer and this was found to correlate with temperature (r = 0.7671; P = 0.0008). A significant correlation was also found between the AOB (amoA gene) copy numbers and temperature in the reactors (α= 0.05; P=0.05), with the lowest AOB abundance recorded during winter. Sanger sequencing analysis indicated that the dominant nitrifiers were Nitrosomonas spp. Nitrobacter spp. and Nitrospira spp. Pyrosequencing revealed significant differences in the AOB population which was 6 times higher during summer compared to winter. The AOB sequences related to uncultured bacterium and uncultured AOB also showed an increase of 133% and 360% respectively when the season changed from winter to summer. This study suggests that vast population of novel, ecologically significant AOB species, which remain unexploited, still inhabit the complex activated sludge communities. Based on ANFIS model, AOB increased during summer season, when temperature was 1.4-fold higher than winter (r 0.517, p 0.048), and HRT decreased by 31% as a result of rainfall (r - 0.741, p 0.002). Food: microorganism ratio (F/M) and HRT formed the optimal combination of two inputs affecting the plant’s specific nitrification (qN), and their quadratic equation showed r2-value of 0.50.
This study has significantly contributed towards understanding the complex relationship between the microbial population dynamics, wastewater composition and nitrification performance in a full-scale treatment plant situated in the subtropical region. This is the first study applying ANFIS technique to describe the nitrification performance at a full-scale WWTP, subjected to dynamic operational parameters. The study also demonstrated the successful application of ANFIS for determining and ranking the impact of various operating parameters on plant’s nitrification performance, which could not be achieved by the conventional spearman correlation due to the non-linearity of the interactions during wastewater treatment. Moreover, this study also represents the first-time amoA gene targeted pyrosequencing of AOB in a full-scale activated sludge is being done. / D
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Avaliações técnico-operacionais em estações de tratamento de água dos municípios das regiões leste e dos lagos do Estado do Rio de Janeiro, com propostas de melhorias para futura implantação de sistema de gestão ambiental baseado nas normas ISO 14.000. / Technical-operational evaluations in water treatment stations of the cities of the regions east and the lakes of Rio de Janeiro State with proposals of improvements for future implantation of environmental management system based in norms ISO 14.000.José Rogério da Conceição Ramos 19 March 2008 (has links)
Na gestão de recursos hídricos, as questões relacionadas aos impactos ambientais
causados pelas Estações de Tratamento de Água não podem ser negligenciadas, devendo ser
avaliadas em todos seus aspectos. Neste trabalho foram avaliadas as condições técnicasoperacionais
e a gestão de seis Estações de Tratamento de Água de pequeno porte situadas nas
regiões leste e dos lagos do estado do Rio de Janeiro. Os resultados apresentam dados de
produção de água tratada, perdas de água contabilizadas com lavagem de filtros e descargas
de decantadores e as não contabilizadas, gastos de energia e produtos químicos, produção de
resíduos e seu destino final, bem como levantamento da capacitação do pessoal de operação,
comparados com valores de literatura para ETAs consideradas eficientes. A partir da
discussão dos resultados concluiu-se que há necessidade de correções de operação e
manutenção das ETAs e monitoramento da qualidade das águas bruta e tratada,
recomendando-se que a empresa de saneamento, efetivamente, implante melhorias para uma
posterior implantação, em cada unidade, de um sistema de gestão ambiental, baseado nas
normas ISO 14.000. / In Water Resources Management the questions related with environmental impact
caused by Water Treatment Plants (WTPs) cannot be neglected, and they must be evaluated in
every aspect. In this work it was evaluated the technical and operational conditions and the
management of six small Water Treatment Plants located on the regions East and the Lakes of
the State of Rio de Janeiro. The result presents data on treated water production, entered water
losses caused by filter cleaning and decantors discharges, and not-entered losses, energy and
chemical products expenses, residual production and its final destination, also the survey of
operational staff capacitation compared to the literature values to the considered efficient
WTPs. From the discussion of the results we conclude that corrections on the operation and
maintenance of the WTPs are necessary, and a management of the raw and treated water
quality, also we recommend to the sanitation service company to improve effectively in a
future implantation a system of ambient management in each unit, based on ISO 14.000.
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Avaliações técnico-operacionais em estações de tratamento de água dos municípios das regiões leste e dos lagos do Estado do Rio de Janeiro, com propostas de melhorias para futura implantação de sistema de gestão ambiental baseado nas normas ISO 14.000. / Technical-operational evaluations in water treatment stations of the cities of the regions east and the lakes of Rio de Janeiro State with proposals of improvements for future implantation of environmental management system based in norms ISO 14.000.José Rogério da Conceição Ramos 19 March 2008 (has links)
Na gestão de recursos hídricos, as questões relacionadas aos impactos ambientais
causados pelas Estações de Tratamento de Água não podem ser negligenciadas, devendo ser
avaliadas em todos seus aspectos. Neste trabalho foram avaliadas as condições técnicasoperacionais
e a gestão de seis Estações de Tratamento de Água de pequeno porte situadas nas
regiões leste e dos lagos do estado do Rio de Janeiro. Os resultados apresentam dados de
produção de água tratada, perdas de água contabilizadas com lavagem de filtros e descargas
de decantadores e as não contabilizadas, gastos de energia e produtos químicos, produção de
resíduos e seu destino final, bem como levantamento da capacitação do pessoal de operação,
comparados com valores de literatura para ETAs consideradas eficientes. A partir da
discussão dos resultados concluiu-se que há necessidade de correções de operação e
manutenção das ETAs e monitoramento da qualidade das águas bruta e tratada,
recomendando-se que a empresa de saneamento, efetivamente, implante melhorias para uma
posterior implantação, em cada unidade, de um sistema de gestão ambiental, baseado nas
normas ISO 14.000. / In Water Resources Management the questions related with environmental impact
caused by Water Treatment Plants (WTPs) cannot be neglected, and they must be evaluated in
every aspect. In this work it was evaluated the technical and operational conditions and the
management of six small Water Treatment Plants located on the regions East and the Lakes of
the State of Rio de Janeiro. The result presents data on treated water production, entered water
losses caused by filter cleaning and decantors discharges, and not-entered losses, energy and
chemical products expenses, residual production and its final destination, also the survey of
operational staff capacitation compared to the literature values to the considered efficient
WTPs. From the discussion of the results we conclude that corrections on the operation and
maintenance of the WTPs are necessary, and a management of the raw and treated water
quality, also we recommend to the sanitation service company to improve effectively in a
future implantation a system of ambient management in each unit, based on ISO 14.000.
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Možnosti využití podpory strukturálních fondů EU na zlepšení kvality životního prostředí / Possibilities of using support of EU Structural Founds in Enhancing the Quality of EnvironmentJIRSA, Aleš January 2010 (has links)
The aim of this thesis is to determine the public awareness about the possibilities of financial support from the EU funds on enhancing the quality of environment with the special emphasis on waste water and the WWTPs in the Czech Republic. It was studied, whether the attitudes and the public awareness play a role in the construction of WWTPs. Whereas the weight of public opinion in decision-making also testifies the extent of public decision making power on the outcomes of decision making about environmental management, the goal of this work is also to verify the degree of public involvement into the public decision making processes.
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Etude de la présence, du devenir et de l’impact des psychotropes dans la Garonne estuarienne (France) et le fleuve Saint Laurent (Québec, Canada) / Presence, fate and impact of psychotropic drugs in the Garonne estuarine (France) and the St. Lawrence River (Quebec, Canada).Pédelucq, Julie 14 December 2016 (has links)
L’urbanisation croissante et la propagation des activités humaines entrainent l’augmentation de l’apport de nombreux micropolluants dans le milieu aquatique. Le compartiment aquatique est alors défini comme le réceptacle ultime de la pollution environnementale apportée par diverses sources : les effluents municipaux et industriels, les lixiviats des sites d’élimination des déchets solides, le ruissellement des eaux urbaines et des eaux des sites agricoles. Parmi les contaminants retrouvés dans l’eau, il y a les psychotropes (benzodiazépines, antidépresseurs,antiépileptiques, etc…) qui appartiennent à la grande famille des médicaments. Ce sont des molécules biologiquement actives, ubiquistes, qui sont principalement d’origine urbaine, qui sont apportées continuellement dans l’environnement aquatique et qui sont fortement consommées au niveau mondial. Depuis quelques années, les scientifiques commencent à s’intéresser à cette famille thérapeutique mais il existe encore un réel manque de connaissance sur l’intégralité du problème de diffusion des psychotropes,de leur passage en station d’épuration à leur présence dans l’environnement et enfin à leur impact sur les organismes aquatiques. Ces travaux de thèse cherchent donc à documenter ce point en se focalisant sur l’étude de la présence, du devenir et de l’impact des psychotropes dans la Garonne estuarienne (France) et le fleuve Saint Laurent (Québec, Canada). Dans un premier temps, une méthode analytique multi-résidus permettant l’analyse de 47 psychotropes dans les eaux usées et les eaux de surface a été développée et validée. Des échantillonneurs passifs de type POCIS (Polar Organic Chemical Integrative Sampler) ont été calibrés et validés afin de permettre le suivi intégratif et continu des psychotropes dans les eaux de surface.Dans un second temps, les effluents d’entrée et de sortie de station d’épuration des agglomérations de Bordeaux en France et de Repentigny et Montréal au Québec ont été caractérisés. Les résultats de cette étude montrent que les traitements épuratoires de chacune des stations d’épurations étudiées ont une efficacité limitée pour éliminer les psychotropes dans les eaux usées. Par la suite, le suivi effectué dans la Garonne estuarienne et dans le fleuve Saint Laurent a mis en évidence la présence de psychotropes dans l’environnement qui sont majoritairement apportés par l’amont des villes de Bordeaux et Montréal.La comparaison des résultats obtenus pour la France et le Québec montre qu’il existe bien des habitudes de prescriptions et de consommations différentes entre les deux pays. Même si les procédés d’épuration sont différents entre les deux pays (traitement secondaire en France et primaire au Québec),l’efficacité d’élimination sur la famille thérapeutique des psychotropes reste insuffisante. Enfin ila été observé que le débit du milieu récepteur jouait un rôle important dans la dilution et le devenir des composés.Dans un troisième et dernier temps, des études in vitro et in vivo ont montré que certains psychotropes pouvaient avoir un impact toxique sur les bivalves d’eau douce étudiés (Elliptio complanata et Corbiculafluminea) lors d’exposition de composés seuls ou en mélange à des concentrations de l’ordre du mg.L-1 (concentrations expérimentales) et même du ng.L-1 (concentrations environnementales). / Increasing urbanization and human activities cause an increase of micropollutant input in the aquatic environment. The water compartment is then defined as the ultimate receptacle of environmental pollution originating from various sources: municipal and industrial wastewaters, leachates from solidwaste disposal sites, waters of urban and agricultural runoff.Among the contaminants found in the water, there are psychotropic drugs (benzodiazepines, antidepressantsor antiepileptics) belonging to the family of pharmaceuticals. These are biologically active molecules, ubiquitous, which are mainly of urban origin, which are continuously introduced into the aquatic environment and are heavily consumed around the world.In recent years, scientists have begun to show interest for this therapeutic family, but there is still areal lack of knowledge about the full psychotropic diffusion problem; from their presence in wastewater treatment plant to their presence in the environment and finally to their impact on aquatic organisms.In this global perspective these thesis works seek to document the presence, fate and impact of psychotropic drugs in the Garonne estuarine (France) and the St. Lawrence River (Quebec, Canada).Firstly, a multi-residue analytical method for the analysis of 47 psychotropic drugs in wastewater and surface waters has been developed and validated. POCIS passive samplers were calibrated and validated for continuous integrative monitoring of psychotropic drugs in surface waters.Secondly, the treatment plant influents and effluents of Bordeaux in France and Repentigny and Montreal in Quebec have been characterized. The results of this study show that treatment processes ofstudied wastewater treatment plants have limited performances to remove psychotropic drugs in wastewaters. There after, the monitoring performed in the Garonne estuarine and in the St. Lawrence River has highlighted that the presence of psychotropic drug in the environment is mainly related toupstream input of Bordeaux and Montréal.Comparison of the results obtained in the two countries surveyed show that there are many different patterns of prescriptions and consumption between the two countries. Although the treatment processes are different between the two countries (secondary treatment in France and primary in Quebec), their removal efficiency is still insufficient for psychotropic drugs. Finally it was observed that theflow rate of the receiving environment plays an important role in the dilution and the fate of the compounds.In a third and final stage, in vitro and in vivo studies have shown that some psychotropic drugs could have a toxic impact on the studied freshwater bivalves (Elliptio complanata and Corbicula fluminea) upon exposure alone or in mixture with concentrations in the order of mg.L-1 (tests concentrations) and even ng.L-1 (environmental concentrations).
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Productive minescape : the rehabilitative and productive relationship between architecture, an open cast mining landscape and the subsistence farming communities, Mogalakwena, LimpopoBoniface, Dean 16 April 2014 (has links)
M.Tech. (Architectural Technology) / This project is an architectural response to a setting shared by an active open cast platinum mine and the surrounding rural traditional subsistence farming communities located in the Mogalakwena municipality, Limpopo Province. The area is characterised by its mine waste landscape and large open cast pits, all of which are remnants of the process of open cast mining. The Mogalakwena communities’ economic livelihood is largely dependent on agricultural land. This land is reducing, partly due to the establishment and expansion of the mine and partly to the increased growth rate of the surrounding communities. This project argues that the remnants of the mining industry (particularly open cast pits, mine waste rock and infrastructure) need not be redundant and can be reused and rehabilitated to result in productive outcomes by establishing the necessary systemic strategy for transposed use. It contends that the proposed reconfi gured mining infrastructure programs can be responsive to context (history, environment and communities), climate and natural processes of the area. In testing the strength of this argument, diff erent research investigations and theories were used as was appropriate to each area of research in this topic. These included, among others, investigations into the history and context of both the mining industry generally, including its legislative context, and the site specifi cally. Considerations of the embedded memory of the site were taken into account. Theories which assisted in leading to a proposed strategy for the site on a contextual scale included theories relating to contextual productive systems, continuous productive urban landscapes, permaculture and biomimicry, augmented landscapes, entropic architecture, architecture as a machine and the mortality of architecture. Ultimately, a proposed solution as an architectural product was sought. The following questions had to be answered in a eff orts to produce an appropriate architectural response to the site and its challenges: 1. How can the role of architecture reconfigure the redundant, disused mine waste landscape so as to harness a rehabilitative and productive system and how can that system be managed by the design? 2. How can contemporary rural agricultural projects be challenged to form new typologies that empower the communities to provide for their own present and future needs? 3. How can architecture as a system be designed to outlast the temporality of its program to transform a redundant open cast mining landscape into a productive landscape? The architectural intervention is a design of reconfi gured structures aimed at facilitating a productive and sustainable environment for agricultural advancement, in order to rehabilitate the existing “minescape” (industrially altered mining land), and reconcile the use of this land with the history of subsistence farming as practiced by members of the surrounding communities. The proposed architectural product strives to create a site and context responsive architectural program or system by fusing technological strategies into the body of architecture that are essentially environmental. It aims to employ air, water, sun, and earth to augment the productive relationship between architecture and the “minescaped” terrain, thereby creating a Productive Minescape, which yields tangible positive by-products such as agriculture, renewable energy, water treatment and harvesting systems, among others. Other productive by-products of the project are education and research facilities and facilities which aim to provide accessibility and reconciliation of the stakeholders of this area, to the site and to each other. The introduction of these systems and facilities will be phase one of the proposed architectural intervention. However, the intervention is networked, and therefore has a scalable logic which is envisaged to grow and develop at a much larger and more intensive scale, suggested to occur over the next 30 years, which are phases two, three and four (see figures 17 and 18).
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The treatment of platinum refinery wastewater using an evaporative crystallizerLuvuno, Jabulani Heavenson 03 1900 (has links)
South Africa is a water scarce country. The expansion of the industrial, mining, and agricultural sectors to meet the needs of South Africa’s growing population requires more water. There is therefore an urgent need to develop effective wastewater treatment processes in order to recover and reuse water. This dissertation presents the treatment of an acidic wastewater stream from a platinum refinery which at present is being disposed of by contract with a waste disposal company. The major concern in treating the acid effluent stream is the high concentration of sodium ions (18 200 mg/l) and chloride ions (104 900 mg/l).
The precipitation process is used to treat wastewater, but ultimately it generates more secondary waste as a sludge. The other process that is used to treat wastewater is reverse osmosis (RO). RO is usually preferred in the last stage of the treatment because the process is more expensive as membranes need to be replaced regularly. The approach used in this research focuses on evaporating liquid, consequently concentrating the remaining solution until the ions in the solution crystallize. The liquid produced is recycled back into the platinum plant for reuse, and the remaining salt crystals are collected as the useful product. The proposed water treatment process produces dilute hydrochloric acid as the condensate and a crystallized sodium chloride rich residue.
The refinery is currently disposing of around 20 000 l/day of wastewater to landfills. The proposed treatment process can recover half of the volume of the wastewater stream to the refinery, helping reduce the fresh water consumption of the process by 10 000 l/day. Furthermore, this will reduce the volume of wastewater going to disposal by a half, namely only 10 000 l/day will need to be disposed of.
The amount of Cl that can be recovered is variable and depends on the quantity of chloride in the wastewater. In the two samples processed the recovery was between a 2,5 w% and 10,7 wt% aqueous HCl solution. This corresponds to a saving of between 250 to 1000 kg/day of HCl. As the concentration of the recovered solution is variable, the recycling process would need to monitor the composition of the recycled stream and make up the acid concentration to some fixed value for reuse in the prices.
The production of a dilute hydrochloric acid stream should be particularly attractive to the platinum refinery as the operation of the refinery requires hydrochloric acid as a feed. Thus, by recycling the wastewater, the refinery would reduce the volume of wastewater to be disposed of thereby reducing the cost of disposal of the waste while simultaneously reducing the cost of buying fresh hydrochloric acid. The proposed recovery of liquid and recycling it back to the refinery, will also reduce the environmental impact of the refinery, and very importantly in a water scarce country, reduce the freshwater consumption of the process. / Physics / M. Sc. (Physics)
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