"Major Subject: Water Management and Hydrological Sciences" Title from author supplied metadata (automated record created 2010-03-12 12:08:51). Includes bibliographical references.

"Major Subject: Water Management and Hydrological Sciences" Title from author supplied metadata (automated record created 2010-03-12 12:08:51). Includes bibliographical references.

"Major Subject: Water Management and Hydrological Sciences" Title from author supplied metadata (automated record created 2010-03-12 12:08:51). Includes bibliographical references.

"Major Subject: Water Management and Hydrological Sciences" Title from author supplied metadata (automated record created 2010-03-12 12:08:51). Includes bibliographical references.

"Major Subject: Water Management and Hydrological Sciences" Title from author supplied metadata (automated record created 2010-03-12 12:08:51). Includes bibliographical references.

Thesis (M. S.)--Texas A&M University, 2006. / "Major Subject: Water management and hydrological sciences " Title from author supplied metadata (automated record created on Sep. 15, 2006.) Vita. Abstract. Includes bibliographical references.

Orientador: Antônio Cezar Leal / Banca: João Lima Sant'Anna Neto / Banca: João Osvaldo Rodrigues Nunes / Banca: Manoel Rodrigues Chaves / Banca: Ana Paula Fracalanza / Resumo: Inicialmente o trabalho apresenta uma reflexão sobre a produção do espaço no capitalismo e sua relação com o papel gestor territorial que o Estado moderno acaba por assumir nos dias atuais, visando garantir as condições necessárias para que possa haver, dentro de suas fronteiras nacionais, a acumulação do capital. Intenta-se mostrar nessa parte o contexto no qual se insere a gestão hídrica em nosso país e de uma porção espacial em particular: a Bacia do Rio Paraibuna. Em seguida, procuramos mostrar que o espaço na Bacia do Rio Paraibuna é fruto das profundas transformações que ocorreram nos vários períodos históricos nessa área. Este trabalho aponta a necessidade de se alargar os horizontes dos processos de gestão hídrica, em especial na Bacia do Rio Paraibuna, valorizando, entre outras coisas, a dimensão local das pequenas comunidades, povoados e cidades, para que se perceba tanto a trama das relações sociais aí presentes quanto o potencial existente para a construção de um processo de gestão hídrica participativa que atenda aos interesses comuns das populações como um todo, em especial nas decisões relativas à utilização das águas. Por fim, a análise realizada conduziu à percepção de que a gestão do território por políticas setoriais desarticuladas, com objetivos diferentes a serem alcançados, e por diferentes âmbitos de poder sem um grau desejável de integração é, também, elemento crucial a limitar as possibilidades de uma gestão hídrica eficiente, pois não assegura a sustentabilidade das águas e dos demais recursos ambientais como condição primordial para um desenvolvimento social abrangente que alcance todas as classes sociais. / Abstract: This study begins with showing a reflexion about the spatial production in Capitalism system and its relation with the territorial management role played by the modern State. For its turn, the State is in charge of, in its national border, supporting the capital accumulation. Therefore, this thesis try to search for the larger context where the water management in each spatial scale of our country is involved. Afterwards, we are based on the idea that the space in the Paraibuna river basin is the result of profound transformations occurred through several historic periods in this area. This study points out the need of enlarging the view predominant in the process of water management, in special, in the Paraibuna River basin. On the way to this new practice it requires valorizing the local dimension of small communities, villages, so that the net of existing social relations and the resources to the building of a participative water management able to answer effective to the population interests as a whole, specially much care to the decisions linked to water usage. At last, this analysis conducted to the perception that territorial management made by partial and disarticulated polices with distinct aims to be reached, and, undertaken by different agents (municipal, state and federal) without a desirable integration are relevant factors on the way to limit a efficient water management capable to guarantee water sustainability and others environmental resources as a prime condition to a social development reaching to all social classes. / Doutor

The thesis studies the case of water quality in Mexico as a crucial factor to prevent water scarcity. This is an important issue for Mexico since more than half of its territory is arid or semi-arid; moreover, the most productive regions are located in areas with significant water resources stress. In this regard, the current situation of water scarcity is studied from the changes in water management derived from the evolution of institutions in the country. The institutional changes were analyzed mostly in the transition from a centralized water supply and sanitation services with strong state intervention to the decentralization of such services that were transferred to municipalities. Decentralization was addressed by analyzing the performance of water supply and sanitation services in urban areas that are expected to continue growing in the near future. The literature shows that the decentralization process has been partial and has not improved as expected the performance of water supply and sanitation services, moreover, due to political reasons, limited human and financial resources it introduced more challenges to the accomplishment of sustainable water management. More importantly, the federal government is still the main agent for the development of the water sector in Mexico. The next part of the analysis consist of a quantitative and qualitative evaluation regarding water quality for the three most productive Hydrological-Administrative Regions (HARs) of Mexico in the period of 2003-2013. The HARs chosen are the HAR VI Río Bravo, HAR VIII Lerma Santiago Pacific and HAR XIII Waters of the Valley of Mexico which are very similar in terms GDP share and water stress degree. Through OLS regression models for each HAR the impacts of demographic, economic, water supply and sanitation services aspects were tested to known their effects on water quality. In order to improve the discussion of the results, additional to the comparison with the results of the literature review, three experts were asked to answer a questionnaire about the regressions outcome. The discussion showed different impacts of the independent variables in the dependent variable of each HAR, sometimes leading to unexpected results. The main conclusions of the thesis relate to the improvement of decentralization of water and sanitation services, to the need to improve data for future analyses and pay more attention to water quality issues. In this regard, decentralization requires to consider contextual differences in order to seize its advantages to improve the performances of water supply and sanitation services, moreover, at the operative level water management decisions must be taken without political interests involved. The statistical analyses stressed the need to develop more reliable data about water management issues to improve the understanding of factors that could potentially affect water quality. In this regard, the creation of useful statistical indicators to assess the evolution towards sustainability in water management. The considerations for future research must consider more seriously water quality issues. This topic has been often ignored, however, it is crucial for water scarcity abatement.

Water is one of Earth's most valuable resources and one of Earth's most threatened resources. Continuously increasing population growth coupled with changing climate has resulted in the depletion of water sources. As a result, investigations into alternative water sources are being conducted worldwide. One such alternative water source is groundwater abstraction. Groundwater abstraction involves the abstraction of water from an underground source. The volume of water that can be sustainably abstracted is governed by legislation. Groundwater typically requires treatment before it can be distributed to the general population for use, and thus the implementation of large-scale groundwater abstraction projects involves large capital outlays, as well as monthly operational outlays. The feasibility into the implementation of large-scale groundwater abstraction projects is therefore of interest to stakeholders involved in the water supply industry. The lifecycle of a recently implemented large-scale groundwater abstraction project was analysed in order to determine its feasibility. The project was implemented by Drakenstein Municipality in the Western Cape in 2017. The project involved identifying groundwater abstraction points that could provide sustainable volumes of water. The water quality of each groundwater abstraction point was then investigated for any outlying parameters according to SANS 241-1:2015 guidelines for potable water. Groundwater abstraction water treatment plants were then designed in order to treat the combined sustainable flow rates of water at their specific water qualities. The treated water from each groundwater abstraction water treatment plant was then analysed in order to confirm compliance with the SANS 241- 1:2015 guidelines, before the booster pumps were commissioned and commenced with their continuous supply of potable water into the network. The capital expenditure associated with each of the groundwater abstraction water treatment plants was obtained from the Engineer, Aurecon. In addition, the estimated monthly operational expenditure was computed. These expenditures were used to determine the feasibility of the large-scale groundwater abstraction project by computing the payback period and comparing this period to the design life of each of the groundwater abstraction water treatment plants. In addition, the monthly savings applicable to the municipality as a result of the project's implementation was computed. Finally, the feasibility into varying flow rates of groundwater abstraction water treatment plants, and varying water quality of groundwater abstraction points was investigated. Two sites were identified within the municipal area, each with four groundwater abstraction points capable of delivering a combined 5.18 ML/day and 1.62 ML/day. These sites were identified as Boy Louw Sportsgrounds and Parys Sportsgrounds respectively. Although the sites were only 2.60 kilometres apart, the water quality of the combined flow rates indicated that the groundwater abstraction points were accessing two different water sources. The combined sustainable flow rate at Boy Louw Sportsgrounds required turbidity, iron and manganese removal, as well as disinfection. The combined sustainable flow rate at Parys Sportsgrounds required turbidity removal and disinfection. Groundwater abstraction water treatment plants were then designed to treat the water at Boy Louw Sportsgrounds and Parys Sportsgrounds. Boy Louw Sportsgrounds involved the distribution of equipment across seven shipping containers, whilst Parys Sportsgrounds involved the distribution of equipment across three shipping containers. It was found that the groundwater abstraction project was feasible with a payback period of three years. This payback period fell well within the 10-year design life of each groundwater abstraction water treatment plant. In addition, it was found that the municipality would be subject to a 72% monthly saving in water costs as a result of utilising the groundwater abstraction water treatment plants, as opposed to purchasing water in bulk from the City of Cape Town. It was found that the payback periods of Boy Louw Sportsgrounds and Parys Sportsgrounds were two and five years respectively. Although Boy Louw Sportsgrounds delivered almost three times the potable water flow rate than that of Parys Sportsgrounds, its payback period was three years sooner. In addition, it was found that the municipal savings as a result of Boy Louw Sportsgrounds was 8% more than that of Parys Sportsgrounds. It was therefore concluded that the larger the flow rate of water to be treated, the more financially feasible the project. In addition, it was determined that the more water quality parameters lying above the upper limits of SANS 241-1:2015 guidelines for potable water, the more treatment processes would need to be implemented resulting in additional capital and operational expenditure. It was therefore concluded that the more water quality parameters requiring treatment, the less financially feasible the project. Finally, it was determined that the feasibility of the large-scale groundwater abstraction project is limited by the rate at which the municipality purchases water in bulk from the City of Cape Town. As long as the bulk water purchase tariff remains above R 2.85/m³, the project will remain feasible. Should the bulk water purchase tariff fall below this value, the project no longer remains feasible as the payback period of the project exceeds the design life of the groundwater abstraction water treatment plants.

Dual Digestion is a two-stage system that combines autothermal thermophilic aerobic pre-treatment with conventional anaerobic digestion. The practicability of the system using pure oxygen is well proven. Disadvantages are the high cost of the pure oxygen and the absence of a detailed evaluation of anaerobic digester performance. This report discusses the results of a full-scale investigation into the dual digestion system (184m³ aerobic reactor and 1800m³ anaerobic digester), carried out in two phases: In the first using air alone for oxygenating the aerobic reactor and in the second using a combination of air and pure oxygen. During both phases the performance of the anaerobic digester was also monitored, but in greater detail in the second phase as far as the final sludge product is concerned. In phase I, with air, it was possible to maintain thermophilic temperatures in the aerobic reactor throughout the year. However, the required retention times were relatively long (3-6 days) in comparison with the pure oxygen reactor (~1 day) due to the high vapour heat losses. At long retention times, the volatile solids (VS) destruction was appreciable (~25%) and the reactor tended towards an autothermal thermophilic digester. Foaming, although unpredictable in its occurrence, significantly improved aerobic reactor performance by doubling the oxygen transfer efficiency. From liquid and gas mass and heat balances it was found that the specific biological heat yield and respiration quotient were approximately constant at 12.8 MJ/kg(O₂) and 0. 70 mol(CO₂)/mol(O₂) respectively over a wide range of operating conditions and consistent relationships between VS removal, heat generation, and oxygen utilisation could be established. Based on information collected, it was concluded that increased treatment capacity and greater temperature control of the aerobic reactor could be provided by supplementing air oxygenation with pure oxygen. In phase II, using a combination of air and pure oxygen, much higher loading rates on the aerobic reactor were possible. Thermophilic temperatures could be maintained at short retention times (1-2 days). Unfortunately, no foaming occurred during this period. Consequently, the benefit of improved oxygen transfer efficiency of the air oxygenation system, produced by the foam, could not be exploited. Liquid and gas mass and heat balances confirmed the specific heat yield and respiration quotient values and the relationship between oxygen utilisation, VS destruction and biological heating. During phase II, the anaerobic digester operated at a retention time of ~10 days. The sensible heat content of the hot sludge from the aerobic reactor was sufficient to force the digester into the thermophilic temperature range. The stability of the anaerobic process and final sludge product at this short retention time was monitored with % VS removal and residual specific oxygen utilisation rate tests and found to be similar to that of conventional mesophilic anaerobic digestion at 20 days retention time. Dewaterability as reflected by the specific resistance to filtration (SRF) was found to be poor, but 11ot much worse than for conventional mesophilic digestion. Sufficient information was obtained during phases I and II to allow a mathematical model to be compiled, which could reasonably reliably simulate all the main operating parameters of the dual digestion system. The model provided a means for assessing different system configurations with mesophilic or thermophilic digestion, with and without heat exchange or gas engine external heat sources, allowing technical and economical (capital and operating) feasibility to be evaluated and compared with that for conventional digestion. From both the experimental and modelled results, all the claimed benefits of the dual digestion system were verified with the exception of the claim that aerobic reactor heat pre-treatment of the sludge allows the anaerobic digester to operate at short retention times (~10 days). However, the digester can be operated at 10 days retention provided its temperature is in the thermophilic range, in which case a sufficiently stable sludge is produced; at mesophilic temperatures, a retention time of 15 days or longer is required to produce a sludge of equivalent stability to that from conventional mesophilic digestion. Consequently, it is not the stability of the anaerobic process per se that governs the minimum retention time but the quality required for the final sludge product. The aerobic reactor is an appropriate pre-treatment stage for the thermophilic digester because it provides the necessary temperature and pH buffering to allow stable operation in the thermophilic range. It is concluded that where application of conventional anaerobic digestion is contemplated, whether for new installations or for upgrading existing plants, the dual digestion system should be seriously considered as a possible option. It competes favourably both technically and economically with conventional mesophilic digestion and produces a superior sludge product which can be beneficially utilised in agriculture.