Thesis (Ph. D.) - L'Université de Clermont II (U.E.R. Sciences exactes et naturelles à dominante recherche), 1978. / At head of title: Série : E ; No. d'ordre : 260.

Yes / The reverse osmosis (RO) process is one of the most popular membrane technologies for the generation of freshwater from seawater and brackish water resources. An industrial scale RO desalination consumes a considerable amount of energy due to the exergy destruction in several units of the process. To mitigate these limitations, several colleagues focused on delivering feasible options to resolve these issues. Most importantly, the intention was to specify the most units responsible for dissipating energy. However, in the literature, no research has been done on the analysis of exergy losses and thermodynamic limitations of the RO system of the Arab Potash Company (APC). Specifically, the RO system of the APC is designed as a medium-sized, multistage, multi pass spiral wound brackish water RO desalination plant with a capacity of 1200 m3/day. Therefore, this paper intends to fill this gap and critically investigate the distribution of exergy destruction by incorporating both physical and chemical exergies of several units and compartments of the RO system. To carry out this study, a sub-model of exergy analysis was collected from the open literature and embedded into the original RO model developed by the authors of this study. The simulation results explored the most sections that cause the highest energy destruction. Specifically, it is confirmed that the major exergy destruction happens in the product stream with 95.8% of the total exergy input. However, the lowest exergy destruction happens in the mixing location of permeate of the first pass of RO desalination system with 62.28% of the total exergy input.

Yes / Reverse Osmosis (RO) process has become one of the most widely utilised technologies for brackish water desalination for its capabilities of producing high-quality water. This paper emphasis on investigating the feasibility of implementing the retentate recycle design on the original design of an industrial medium-sized multistage and multi-pass spiral wound brackish water RO desalination plant (1200 m³/day) of Arab Potash Company (APC) located in Jordan. Specifically, this research explores the impact of recycling the high salinity stream of the 1st pass (at different recycled percentages) to the feed stream on the process performance indicators include, the fresh water salinity, overall recovery rate, and specific energy consumption. The simulation is carried out using an earlier model developed by the same authors for the specified RO plant using gPROMS suits. This confirmed the possibility of increasing the product capacity by around 3% with 100% recycle percentage of the high salinity retentate stream.

The Cienega de Santa Clara is a 5600 ha, anthropogenic wetland in the delta of the Colorado River in Mexico. It is the inadvertent creation of the disposal of brackish agricultural waste water from the U.S. into the intertidal zone of the river delta in Mexico, but has become an internationally important wetland for resident and migratory water birds. The marsh is dominated by Typha domengensis with Phragmites australis as a sub-dominant species in shallower marsh areas. The most important factor controlling vegetation density was fire. The second significant (P<0.01) factor controlling NDVI was flow rate of agricultural drain water from the U.S. into the marsh. Reduced summer flows in 2001 due to canal repairs, and in 2010 during the YDP test run, produced the two lowest NDVI values of the time series from 2000 to 2011 (P<0.05). Salinity is a further determinant of vegetation dynamics as determined by greenhouse experiments, but was nearly constant over the period 2000 to 2011, so it was not a significant variable in regression analyses. Evapotranspiration (ET) and other water balance components were measured in Cienega de Santa Clara; we used a remote sensing algorithm to estimate ET from meteorological data and Enhanced Vegetation Index values from the Moderate Resolution Imaging Spectrometer (MODIS) sensors on the Terra satellite. We used Landsat NDVI imagery from 1978-2011 to determine the area and intensity of vegetation and to estimate evapotranspiration (ET) to construct a water balance. Remote sensing data was supplemented with hydrological data, site surveys and literature citations. The vegetated area increased from 1978 to 1995 and has been constant at about 4200 ha since then. The dominant vegetation type is Typha domingensis (southern cattail), and peak summer NDVI since 1995 has been stable at 0.379 (SD = 0.016), about half of NDVI(max). About 30% of the inflow water is consumed in ET, with the remainder exiting the Cienega as outflow water, mainly during winter months when T. domingensis is dormant.

With the continual concern over the presence of naturally occurring and anthropogenic inorganic and trace organic contaminants in the aquatic environment there is a growing need for the implementation of innovative treatment processes for the elimination of these contaminants from natural waters and wastewater effluents. While conventional treatment methods are ineffective in the removal of emerging contaminants such as steroidal hormones and pesticides, membrane technology, including electrodialysis (ED), has been highlighted as a potential treatment option. However, the clear lack of fundamental understanding of the behaviour of contaminants in ED is a current limitation for its extensive utilisation and is a critical issue that needs to be addressed. ED processing potentialities have not been fully exploited and more research is needed to account for all the key parameters such as contaminant physicochemical properties, solution chemistry and the presence of organic matter. The purpose of this study was to elucidate the mechanisms of inorganic and trace organic contaminant removal by ED. The inorganic contaminants fluoride, nitrate and boron were selected due to their ubiquitous nature in the environment and public health concerns resulting from longterm exposure. The hydrated radius and strength of hydration shells played a significant role in ionic transport, whereby nitrate with a smaller hydrated radius was removed more effectively (94.1 %) than fluoride (68.3 %) with a larger hydrated radius. While fluoride and nitrate removal was pH independent, the pH dependent speciation of boron enhanced its removal with increasing pH. Territorial binding and/or complexation of the inorganics with organic matter enhanced removal. The removal of a range of trace inorganics (e.g. arsenic, calcium, magnesium, uranium) from a brackish groundwater from a remote Australian community was investigated. Undissociated inorganics were not transported through the membranes, whereas dissociated inorganics were due to electrostatic attraction. At acidic-neutral conditions ionic transport was the dominant removal mechanism. At neutral to alkaline conditions insoluble carbonate species precipitated and deposited as a membrane scaling layer (60 μm). This has serious implications for the long-term practical applicability of ED to treat real waters as scaling increased ED stack resistance (pH 3: 27.5 4, pH 11: 50 4) and decreased total dissolved solids removal (pH 3: 99 %, pH 11: 89.5 %). While the treatment of trace organics by other membrane processes has been widely studied, their fate in ED and interaction with ED membranes is relatively unknown. Trace contaminant-membrane interaction studies were undertaken to quantify the partitioning of trace organics; namely steroidal hormones and the pesticide endosulfan, to ED membranes by measuring membrane-water partition coefficients (log KM). The extremely high sorption capacity of the membranes was attributed to hydrogen bonding between the trace organic and membrane functional groups. Hormone sorption during ED was influenced by solution pH and organic matter. In the case of estrone, membrane sorption decreased at pH 11 (487 μg/cm3) compared to pH 7 (591 μg/cm3) due to dissociation and membrane electrostatic repulsion .At pH 11, repulsion between dissociated estrone and HA coupled with membrane electrostatic attraction resulted in increased sorption. The findings from this study highlight that the transport of trace contaminants will depend largely on the characteristics of the membranes used in the ED process as well as the physicochemical characteristics of the contaminants, their interaction with the ED membranes and the presence of other inorganic and/or organic compounds. The knowledge gained has direct applications to current problems and uncertainties in water and wastewater treatment with regards to the fate and transport of contaminants.

The Mekong Delta, which is considered as the main 'rice bowl and fish basket', is one of seven distinct agro-ecological regions of Vietnam and plays an important role in the economy of the country. Several rice-based farming systems have been developed in various areas of the MD. Rice-shrimp integrated system in brackish areas is a special farming system developed in this delta. It is a profitable system and seems to be environmentally safe on the one hand without the use of pesticides. On the other hand, use of brackish water in this system may result in degradation of land, as some previous studies have found. To understand how this farming system works and to identify the external and internal factors influencing its sustainability, the project 'Sustainability of rice-shrimp farming system in a brackish area in the Mekong delta of Vietnam' was carried out in 1992-1993 by an interdisciplinary team of researchers from the University of Cantho and staff of local district Agricultural Office, representing different fields of sciences. The research methodology was the Farming Systems Research approach with modifications towards soft systems thinking, involving farmers into the research process. One main result of this study is an insight into the rice-shrimp farming system. It includes various physical, biological, technological, economical and sociological aspects of rice production prior to integration and in integrated farm, naturally supplied shrimp growing and giant shrimp rearing, upland crop production as well as off-farm and non-farm work of farm households. Sustainability of the system studied is assessed, in comparison with rice monoculture, through various criteria of the three view points productivity, environmental safety and socio-economic effectiveness. In terms of such points of view, rice-shrimp farming system is rated higher than rice monoculture system. Thus the integrated system so far is considered to be more sustainable than the others. / Master of Science (Hons)

<p>The carbon metabolism in costal sediments is of major importance for the global carbon cycle. Costal sediments are also subjected to physical forcing generating water fluxes above and through the sediments, but how the physical affect the carbon metabolism is currently poorly known. In this study, the effect of advective pore water flow on degradation of organic matter in permeable sandy sediment was investigated in a laboratory study during wintertime. Sediments were collected from both brackish water (Askö) and from a fresh water stream (Getå Stream). In two chamber experiments, with and without advective pore water flow, the degradation of organic matter was measured through carbon dioxide analysis from water and headspace. In Askö sediments mineralization rates ranged from 3.019 - 5.115 mmol C m-2 d-1 and 3.139 mmol C m-2 d-1 with and without advective pore water flow, respectively. Those results correspond with results from earlier studies of carbon mineralization rates in sediment in the North Sea and the Baltic Sea. There were no significant differences between the two groups in the Askö sediment. In Getå Stream sediments mineralization rates ranged between 4.059 mmol C m-2 d-1 and 6.806 mmol C m-2 d-1 with and without advective flow, respectively. The mineralization rates for Getå Stream correspond with earlier studies of carbon mineralization rates in a stream in New Hampshire.</p>

The carbon metabolism in costal sediments is of major importance for the global carbon cycle. Costal sediments are also subjected to physical forcing generating water fluxes above and through the sediments, but how the physical affect the carbon metabolism is currently poorly known. In this study, the effect of advective pore water flow on degradation of organic matter in permeable sandy sediment was investigated in a laboratory study during wintertime. Sediments were collected from both brackish water (Askö) and from a fresh water stream (Getå Stream). In two chamber experiments, with and without advective pore water flow, the degradation of organic matter was measured through carbon dioxide analysis from water and headspace. In Askö sediments mineralization rates ranged from 3.019 - 5.115 mmol C m-2 d-1 and 3.139 mmol C m-2 d-1 with and without advective pore water flow, respectively. Those results correspond with results from earlier studies of carbon mineralization rates in sediment in the North Sea and the Baltic Sea. There were no significant differences between the two groups in the Askö sediment. In Getå Stream sediments mineralization rates ranged between 4.059 mmol C m-2 d-1 and 6.806 mmol C m-2 d-1 with and without advective flow, respectively. The mineralization rates for Getå Stream correspond with earlier studies of carbon mineralization rates in a stream in New Hampshire.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 210-214). Also available on the World Wide Web.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-10-18T12:30:31Z No. of bitstreams: 1 ADEMIR MORAIS DE MEDEIROS - DISSERTAÇÃO (PPGEQ) 2017.pdf: 3204134 bytes, checksum: c8135684c13cdcbef03ebfe63c7a1c99 (MD5) / Made available in DSpace on 2018-10-18T12:30:31Z (GMT). No. of bitstreams: 1 ADEMIR MORAIS DE MEDEIROS - DISSERTAÇÃO (PPGEQ) 2017.pdf: 3204134 bytes, checksum: c8135684c13cdcbef03ebfe63c7a1c99 (MD5) Previous issue date: 2017-10-30 / Capes / A dessalinização é um processo bastante difundido e utilizado no mundo para o tratamento de águas de diversas fontes hídricas as quais necessitam de tratamento para tornar-se potável e assim promover a segurança hídrica e a manutenção da vida, embora pouco utilizada na proporção necessária, a dessalinização de águas no Nordeste Brasileiro vem se tornando uma técnica bastante requisitada devido sua eficiência no tratamento de águas. O objetivo desta pesquisa foi avaliar a qualidade do permeado de um sistema hibrido de membranas para fins de dessalinização de águas salobras com a remoção do gás carbônico por uma torre de resfriamento, avaliando o desempenho do processo de separação por membrana para tratamento de águas através de estudo avaliativo dos dados reais com os simulados ambos para o permeado da OI. Os dados teóricos são os resultados obtidos a partir de análises reais realizadas nas águas do presente trabalho, inseridos no SOFWARE ROSA® 8.0.3 e realizada as simulações. No presente trabalho utilizou-se a membrana polimérica de Osmose Inversa (BW30 4040) na simulação e nos experimentos de bancadas. A partir da simulação foi possível ajustar as pressões de operação para os seguintes valores: 6, 9, 11, e 13 bar, para água de superfície e 13 e 15 bar para água de poço. Avaliou-se a rejeição de sais (%RS) obtendo valores próximos de 98 % para o permeado. Estudou-se por meio de uma torre de resfriamento como um pós-tratamento, a remoção de CO2 que apresentou como efeito, a diminuição do pH do permeado. Verificou-se através de análises que após a torre de ocorreu uma remoção parcial média de dióxido de carbono de cerca 75 %. / Desalination is a widely used process in the world for the treatment of water from a variety of water sources, which requires treatment to become potable and thus promote water safety and life-support, although little used in the necessary proportion, to desalination of water in the Brazilian Northeast has become a highly requested technique due to its efficiency in water treatment. The objective of this research was to evaluate the permeate quality of a hybrid membrane system for desalination of brackish water with the removal of carbon dioxide by a cooling tower, evaluating the performance of the membrane separation process for water treatment through evaluation of the real data with the simulated ones for the RO permeate. Theoretical data are the results obtained from real analyzes performed in the waters of the present work, inserted in SOFWARE ROSA® 8.0.3 and the simulations were performed. In the present work the polymer membrane of Reverse Osmosis (BW304040) was used in the simulation and bench experiments. From the simulation it was possible to adjust the operating pressures to the following values: 6 bar 9 bar, 11bar, and 13 bar for surface water and 13 bar and 15 bar for well water. The salt rejection (% SR) was evaluated, obtaining values close to 98% for the permeate. It was studied by means of a cooling tower as a post-treatment, the removal of CO2 that had as effect, the decrease of the pH of the permeate. It was verified through analyzes that after the tower a mean partial removal of carbon dioxide of about 75% occurred.