Salinity is one of the major problems that the coastal region of Bangladesh has been facing over ... more Salinity is one of the major problems that the coastal region of Bangladesh has been facing over the last couple of decades. Due to sea level rise, frequent natural disasters, changes of climate patterns and man-made alteration of natural settings, the situation is becoming more vulnerable day by day. It has also been observed th
Many countries’ water resources are limited in both quantity and quality. While engineering solut... more Many countries’ water resources are limited in both quantity and quality. While engineering solutions can now safely produce recycled and desalinated water from non-potable sources at a relatively low cost, the general public is sceptical about adopting these alternative water sources. Social scientists, policy makers and technical experts need to better understand what is causing this lack of acceptance by the general population and how acceptance levels for recycled and desalinated water can be increased. This study is the first to conduct a comparative analysis of knowledge, perceptions, and acceptability, and determine segments of residents who are more open-minded than the general population toward the use of recycled and desalinated water. The Australian population once perceived desalinated water as environmentally unfriendly, and recycled water as a public health hazard. The general level of knowledge about these two concepts as potential water sources has historically been low. After nearly five years of serious drought, accompanied by severe water restrictions across most of the country, and subsequent media attention on solutions to water scarcity, Australians now show more acceptance of desalinated water for close-to-body uses, and less resistance to recycled water for garden watering and cleaning uses. The types of people likely to be strong accepters of the two alternative water sources are distinctly different groups, and can be reached through different media mixes. This finding has significant implications for policy makers and water practitioners.
Salinity is one of the major problems that the coastal region of Bangladesh has been facing over ... more Salinity is one of the major problems that the coastal region of Bangladesh has been facing over the last couple of decades. Due to sea level rise, frequent natural disasters, changes of climate patterns and man-made alteration of natural settings, the situation is becoming more vulnerable day by day. It has also been observed th
This paper presents the study of a water desalination new design process working with the humidif... more This paper presents the study of a water desalination new design process working with the humidification-dehumidification (HD) method using solar energy. This process was developed in order to boost the productivity of the solar multiple condensation evaporation cycle unit which is located at the national school of engineering of Sfax, Tunisia, by integrating into the latter a flat-plate solar air collector and a humidifier. The HD process is essentially composed of a flat-plate solar air collector, a flat-plate solar water collector, a humidifier, an evaporation tower and a condensation tower. A general model based on heat and mass transfers in each component of the unit has been developed in a steady-state regime. The obtained set of ordinary differential equations has been converted to a set of algebraic system of equations by the functional approximation method of orthogonal collocation. The developed model is used to simulate the HD system in order to investigate the steady-state behavior of each component of the unit and the entire system exposed to a variation of the entrance parameters and meteorological conditions.
More than 90% of the population of the Gaza Strip depends on desalinated water for drinking purpo... more More than 90% of the population of the Gaza Strip depends on desalinated water for drinking purposes. About 90% of the groundwater is unacceptable for drinking as a result of contamination by nitrate and chloride. One of the major options for resolving the water problems is the utilization of desalination technology for both sea and brackish water. The objective of this article is to address desalination water management in its embryonic stage in the Gaza Strip. The sources of drinking water supply, distribution system and the environmental impact of brine water will be fingered in detail. Desalination facilities range from large seawater plants to small brackish desalination units on a home scale. Governmental, non-governmental and private desalination plants are common. The distribution system of desalinated water is a responsibility of governmental, non-governmental, private small community bodies and even individuals. Disposal of brine water is made either directly or indirectly into the sea, sewage system, poor land, channels, wadies, etc. Brine constituents have an adverse impacton the surrounding environment, e.g., sea life, soil, wastewater treatment plants and the groundwateraquifer. The lack of real environmental impact assessments, especially for mid- and home-scale units may lead to a deterioration of the environment. The fragmentation of the responsibilities of water desalination, distribution of desalinated water and the disposal of brine water suggest that urgent action should be taken (e.g., legislation or establishment of a supervisory body). In other words, strict policies and management actions are to be taken in order to alleviate the health and environmental impact of an important and uncontrolled new system.
Salinity is one of the major problems that the coastal region of Bangladesh has been facing over ... more Salinity is one of the major problems that the coastal region of Bangladesh has been facing over the last couple of decades. Due to sea level rise, frequent natural disasters, changes of climate patterns and man-made alteration of natural settings, the situation is becoming more vulnerable day by day. It has also been observed th
Electrodialysis (ED) is applied in Japan for seawater concentrating to ca. TDS 200 followed by th... more Electrodialysis (ED) is applied in Japan for seawater concentrating to ca. TDS 200 followed by thermal concentration and salt crystallization. A partially desalinated water (ED diluate) is obtained at the same time. Its further desalination for potable water production may be considered to decrease costs of ED by obtaining two valuable products instead of mere salt. Univalent ion permeable ion-exchange membranes are however applied in ED process and as a result the contents of calcium, magnesium and sulfate ions in diluate are relatively high (in relation to chloride), which makes any further processing difficult. Electrodialysis reversal (EDR) may overcome these shortcomings. The salinity of partially desalinated water is as high as TDS 22.9. If dual-purpose desalination-salt production electrodialysis concern is high degree of desalination, which is however necessary, this implicates many problems in the ED process that are the result of major differences in ED concentrate and diluate concentrations and the small conductivity of potable water grade diluate. Electrodialysis of seawater was investigated in a two-step stand with ED-MSF-Crystallization system being the first stage. Univalent ion permeable Tokuyama Co. ACS and CMS membranes were applied in the first step and normal grade CMV, AMV Asahi Glass membranes in the second step (for the first step diluate treating). ED stack developed by the author and equipped with 0.19 mm spacer was applied. A single-pass low residence time mode of operation was applied to avoid gypsum crystallization in the second step ED concentrate. The first step diluate containing, in g/L, Ca2+—0.38, Mg2+—1.26, Cl−—4.08, SO42-—2.78 was treated by EDR yielding 90% recovery. Potable water grade EDR diluate was obtained. No gypsum crystallization in the EDR concentrate was observed despite its 360% saturation. The total water recovery of ED-MSF-crystallization system is equal to 90%. As there are two valuable products in the described process, the cost of each of them is obviously related to their selling price. IF $30 per one ton of salt is assumed, the potable water cost is estimated to be only $0.44/m3.
A two-year research program on solar photovoltaic desalination of brackish water by electrodialys... more A two-year research program on solar photovoltaic desalination of brackish water by electrodialysis was carried out in the remote area of Fukue City, Nagasaki Prefecture. The standard of water produced was found suitable for drinking, the quantity exceeded expectations, and the system was found reliable for practical use.
The potabilization process of desalinated water used at the Royal Commission power and water comp... more The potabilization process of desalinated water used at the Royal Commission power and water complex located in Madinat Yanbu Al-Sinaiyah (MYAS) consists of four unit operations, namely liming, carbonation, chlorination and aeration. The water is remineralized by adding hydrated lime and carbon dioxide through the liming and carbonation step, thereby raising hardness, alkalinity, pH and dissolved solids content. The chlorination is carried out by the injection of chlorine gas to disinfect the water and eliminate bacterial growth. The aeration is done to replace oxygen driven out by the multi-stage flash distillation process, thereby improving the taste of the water. This paper describes the potabilization facilities and discusses the plant operating data with water quality parameters of the potabilized water.
Some countries (e.g. Korea, China, India, Pakistan, Japan) were forced to adopt the nuclear energ... more Some countries (e.g. Korea, China, India, Pakistan, Japan) were forced to adopt the nuclear energy option to generate electric power Ep (by nuclear power plants NPP) and desalt seawater D (by nuclear desalination ND) due to the rising cost of fossil fuel and its insecure supply. The increase of fuel oil consumption and cost (more than $100 per barrel) motivate other countries, even oil exporting countries, to look for cheaper alternatives to produce both Ep and D. The locally consumed oil in these countries is deducted from its reserves and/or decreases its income. In addition, the green house gases (GHG) emission resulting from burning fossil fuel contributes to global warming and adversely affects the environment. In Kuwait and other Gulf cooperation countries (GCC), huge amounts of fuel (oil and natural gas) are consumed by co-generation power desalting plants (CPDP) to produce Ep and D. The use of this fuel to produce Ep and D cannot be expanded indefinitely as the oil supplies are finite and dwindling. Thus, less costly and sustainable new sources of energy such as solar, geothermal, wave, and wind energies are explored. The share of usage for these sources are so little and their wide expansions in the next decade are doubtful. Presently, nuclear energy is economically viable, and is a large-scale alternative to fossil fuel for generations of Ep and D. The use of nuclear energy (NE) raises many concerns about its safety, high capital cost, and radiation effects on surroundings and workers in the short and long term. The question raised should not be either to accept NPP or not, as it may be the only choice we have. The real questions are: how and when NPP will be inherently safe, economical, and when can it be applied safely in countries at different stages of development. Nuclear energy can present a sustainable way to produce Ep and D if its standing problems can be resolved. It can become a significant option for meeting the future world energy needs at low cost and in an environmentally acceptable manner. In this paper, the prospects of using nuclear cogeneation power desalting plants (N-CPDP) in Kuwait and some of the GCC are discussed. The conditions required to build NCPDP and its associated problems are outlined and discussed.
The IDAE is a public entity of the Ministry of Industry and Energy which belongs to the Departmen... more The IDAE is a public entity of the Ministry of Industry and Energy which belongs to the Department of Energy and Mineral Resources. Its objective is to improve energy efficiency in the use of energy in the different consumer sectors and to promote production and consumption of renewable energies. The work of the IDAE in the different consumer sectors is derived from action planned in the Energy Saving and Efficiency Plan (ESEP) of the National Energy Plan 91/2000 and from strategies identified in the New Promotion of Spain's Energy Saving Policy, which includes thinking ahead to promote activities so that consumer sectors will be able to avoid having to take costly corrective measures - where feasible - in the future. The activities to promote energy efficiency are therefore of particular interest in the new desalination sector which is already working on a large scale in Spain.
The cost of producing electricity with OTEC plants is compared to the cost of electricity produce... more The cost of producing electricity with OTEC plants is compared to the cost of electricity produced with fossil-fueled plants to establish scenarios under which OTEC could be competitive. In the case of OTEC, when appropriate, the cost of electricity is estimated with credit for the desalinated water produced. Two generalized markets are considered:
Even though the volume of the earth's water is vast, less than 10 million of the 1,400 million cu... more Even though the volume of the earth's water is vast, less than 10 million of the 1,400 million cubic metres of water on the planet is of low salinity and suitable for use after applying conventional water treatment alone. The other 97.5% of the water on our planet is to be found in the oceans, where it is officially classified as seawater.Desalination provides a means of tapping this resource, and over the last 30 years, seawater desalination technology has made great strides in many arid regions of the world, such as the Middle East and the Mediterranean, and is starting to be considered viable even in cooler regions of the world not traditionally associated with water shortage (the UK for example.)Filtration + Separation looks at the subject of desalination, starting with an overview of the current situation; we ask some experts in the field to point out the reasons why desalination has now become such an acceptable worldwide water treatment phenomenon (Factors behind the growth in desalination - below, and pages 15 – 18.)On page 19, we briefly examine the different technical aspects of desalination available today (Desalination – the basics.)We then publish two case studies; the first looks at Israel, which has embarked upon a large-scale seawater desalination program, most notably the Ashkelon project – a 100 million m3/year SWRO desalination plant (Case study: assessing the need for, and costs of, seawater desalination in Israel - pages 20 and 21.)The second looks at Pretreatment - a vital part of any desalination process – using the US, California, Carlsbad seawater desalination pilot plant as an example (Case study: Pretreatment at Carlsbad seawater desalination pilot plant – pages 22 – 25.)
Vacuum desalination is a process by which water is vaporized at a lower temperature when subjecte... more Vacuum desalination is a process by which water is vaporized at a lower temperature when subjected to vacuum pressure. The heat energy requirement for desalination using a distillation process can be brought down by reducing the boiling temperature. The boiling temperature of seawater can be lowered to as low as 400°C by the creation of a vacuum. Using waste heat from a steam turbine, a pilot study was conducted in the laboratory to investigate the feasibility of using a vacuum desalination process for water supply. The treatment system is designed to minimize the heat requirement. Initially, the seawater is converted to a wet steam in a saturated vapour heater. This vapour heater receives heat from the superheated steam which is due for condensation. The dry component of the wet steam is heated to superheated condition by a superheated vapour heater. This superheated vapour heater receives heat from the waste heat from a steam turbine. Superheated vapour is used to covert incoming seawater to wet steam and then be condensed as the product of the system for potable use. The investigation shows that a vacuum desalination system using turbine exhaust waste steam is possible and has several advantages. Seawater can be boiled at a lower temperature and thus save in energy consumption. Based on experimental results, water boils at 40–90°C at the corresponding vacuum pressure of 0.1–0.7 bar, respectively. The consumption of heat from the waste steam is minimized as the superheated vapour is used to heat the influent seawater. Most of the heat from the waste heat is required to compensate for the heat losses in the system. The energy efficiency of the system depends very much on decreasing the heat losses from the system. It is possible to use nonconventional energy sources such as lower pressure waste steam for vacuum desalination. Hard scale formation in the system can be minimized as scale forming is the major problem in a high temperature distillation process. The qualities of distillates are excellent.
When chemical disinfection is applied before or after desalination systems, compounds may be form... more When chemical disinfection is applied before or after desalination systems, compounds may be formed that pose potential risks to the health of human and aquatic organisms or impact aesthetic quality of drinking water. The formation and speciation of disinfection by-products (DBPs) in desalination systems is affected by the elevated concentrations of bromide and iodide in seawater and desalinated product water. To gain insight into DBPs likely to be formed in desalination systems, DBP studies conducted in saline source waters, coastal power stations and existing desalination systems are reviewed. Chlorination is the most common disinfectant used in current desalination systems, with chloramines and chlorine dioxide gaining more popularity for disinfection of desalinated water. When seawater or reverse osmosis permeate is chlorinated, bromoform (CHBr3) and brominated haloacetic acids (e.g. monobromoacetic acid, dibromoacetic acid, bromochloroacetic acid) are found to be the prevalent DBP species. Under conditions typically encountered in desalination systems, concentrations of these DBPs in the product drinking water are below levels of concern set by regulating agencies. Less information is available on the formation of other haloorganic DBPs in desalination plants. Among DBPs identified in saline drinking waters, haloacetonitriles (HANs), mutagen X compounds (MX), halonitromethanes (HNMs) and cyanogens bromide (CNBr) pose potential concerns, especially when desalinated waters are blended with organic-matter rich source waters.
Bromine and iodine have been utilized in this study as heat generating media for the enhancement ... more Bromine and iodine have been utilized in this study as heat generating media for the enhancement of overall efficiency of the simple conventional basin type solar stills.Results of the experimental work showed that the solar still of bromine medium has a higher efficiency than that of iodine medium. However, both stills have significantly higher efficiencies when compared with that of the conventional one. Also, the results showed that the productivity of the still of bromine medium is about 65% greater than the conventional still. For an iodine medium still the productivity is about 42% greater than the conventional one.
Salinity is one of the major problems that the coastal region of Bangladesh has been facing over ... more Salinity is one of the major problems that the coastal region of Bangladesh has been facing over the last couple of decades. Due to sea level rise, frequent natural disasters, changes of climate patterns and man-made alteration of natural settings, the situation is becoming more vulnerable day by day. It has also been observed th
The paper presents an attempt to assess sustainability of desalination plants for water productio... more The paper presents an attempt to assess sustainability of desalination plants for water production based on resource, environmental and economic indicators. Four types of desalination plants are taken into a consideration: single MSF, dual purpose MSF, RO with local energy consumption and RO with PV electric energy production. The analysis is based on data from desalination plants in Gulf countries. In particular, it reflects water production demand and energy sources used for the individual plants. The decision-making procedure in the sustainability assessment of desalination plants is based on the multi-criteria evaluation under uncertainty of complex systems expressed by the General Sustainability Index. Evaluation of different cases reflecting priority of the criteria for evaluation has led to the selection of options, which are in compliance with respective criteria.
Desalination market growth has triggered significant development in SWRO membrane and process dev... more Desalination market growth has triggered significant development in SWRO membrane and process development and the new extra high rejection and ultra low energy membranes from Dow, FILMTEC™ SW30XHR-400i and SW30ULE-400i, as well as the internally staged design concept, have been validated in extensive field testing and various commercial plants over the recent years and are now commercially available. These solutions from Dow can be used to increase membrane flux and system recovery and / or to reduce feed pressure. This yields capital cost and /or energy savings. These savings have been assessed in 4 different situations / geographies, using a thorough and validated cost model. These geographies are South Pacific (Australia), Persian Gulf (Saudi Arabia), with very different feed water qualities (in terms of feed salinity and temperature range) and product quality requirements (in terms of bromide, boron and salinity). Depending on the cost savings route chosen, there are strong differences in the consequences with regards to size of the RO stage (17-26% smaller), size of the pretreatment (9-12% smaller), and/or the feed pressure (2-6 bar lower). These cost savings are in the range of US cent 0.4-4.1/m³ water produced. This is equivalent to 0.7-6.5% water cost saving. Considering that these considerable cost savings are readily available since 2008 from Dow Water Solutions, the industry should start to significantly benefit from these in the coming years.
Cyprus suffers from droughts, which sometimes continue for a number of consecutive years and crea... more Cyprus suffers from droughts, which sometimes continue for a number of consecutive years and create serious water shortage problems. In the past the efforts of the Government were towards the erection of dams, but the water management system dependence on the weather was not alleviated. The first reverse osmosis desalination plant was erected 5 years ago. Three more plants, one of the same capacity and two with half, are planned in the near future. The Government believes that with the completion of all these plants, the water shortage problem will be solved permanently. As Cyprus has no fossil fuel resources, it relies entirely on fuel imports for its energy needs. It is estimated that 25% of the price of the desalinated water is attributed to the energy cost. This is a parameter that should never be underestimated as all plants are powered with electricity, which is produced entirely from imported fuels. The only natural resource of Cyprus is solar energy, which is abundantly available. It is thus sensible to develop desalination systems which can even partly be powered from solar energy systems, either through a combination of photovoltaics and the existing or planned reverse osmosis systems or from a combination of solar thermal and distillation evaporators. The first one is considered in this paper. These are all mature technologies and thus the financial risk from their implementation is minimum. The added benefit from the adoption of renewable energy sources, besides the issues related to environmental protection, is that they reduce dependency on imported fuels.
Salinity is one of the major problems that the coastal region of Bangladesh has been facing over ... more Salinity is one of the major problems that the coastal region of Bangladesh has been facing over the last couple of decades. Due to sea level rise, frequent natural disasters, changes of climate patterns and man-made alteration of natural settings, the situation is becoming more vulnerable day by day. It has also been observed th
Many countries’ water resources are limited in both quantity and quality. While engineering solut... more Many countries’ water resources are limited in both quantity and quality. While engineering solutions can now safely produce recycled and desalinated water from non-potable sources at a relatively low cost, the general public is sceptical about adopting these alternative water sources. Social scientists, policy makers and technical experts need to better understand what is causing this lack of acceptance by the general population and how acceptance levels for recycled and desalinated water can be increased. This study is the first to conduct a comparative analysis of knowledge, perceptions, and acceptability, and determine segments of residents who are more open-minded than the general population toward the use of recycled and desalinated water. The Australian population once perceived desalinated water as environmentally unfriendly, and recycled water as a public health hazard. The general level of knowledge about these two concepts as potential water sources has historically been low. After nearly five years of serious drought, accompanied by severe water restrictions across most of the country, and subsequent media attention on solutions to water scarcity, Australians now show more acceptance of desalinated water for close-to-body uses, and less resistance to recycled water for garden watering and cleaning uses. The types of people likely to be strong accepters of the two alternative water sources are distinctly different groups, and can be reached through different media mixes. This finding has significant implications for policy makers and water practitioners.
Salinity is one of the major problems that the coastal region of Bangladesh has been facing over ... more Salinity is one of the major problems that the coastal region of Bangladesh has been facing over the last couple of decades. Due to sea level rise, frequent natural disasters, changes of climate patterns and man-made alteration of natural settings, the situation is becoming more vulnerable day by day. It has also been observed th
This paper presents the study of a water desalination new design process working with the humidif... more This paper presents the study of a water desalination new design process working with the humidification-dehumidification (HD) method using solar energy. This process was developed in order to boost the productivity of the solar multiple condensation evaporation cycle unit which is located at the national school of engineering of Sfax, Tunisia, by integrating into the latter a flat-plate solar air collector and a humidifier. The HD process is essentially composed of a flat-plate solar air collector, a flat-plate solar water collector, a humidifier, an evaporation tower and a condensation tower. A general model based on heat and mass transfers in each component of the unit has been developed in a steady-state regime. The obtained set of ordinary differential equations has been converted to a set of algebraic system of equations by the functional approximation method of orthogonal collocation. The developed model is used to simulate the HD system in order to investigate the steady-state behavior of each component of the unit and the entire system exposed to a variation of the entrance parameters and meteorological conditions.
More than 90% of the population of the Gaza Strip depends on desalinated water for drinking purpo... more More than 90% of the population of the Gaza Strip depends on desalinated water for drinking purposes. About 90% of the groundwater is unacceptable for drinking as a result of contamination by nitrate and chloride. One of the major options for resolving the water problems is the utilization of desalination technology for both sea and brackish water. The objective of this article is to address desalination water management in its embryonic stage in the Gaza Strip. The sources of drinking water supply, distribution system and the environmental impact of brine water will be fingered in detail. Desalination facilities range from large seawater plants to small brackish desalination units on a home scale. Governmental, non-governmental and private desalination plants are common. The distribution system of desalinated water is a responsibility of governmental, non-governmental, private small community bodies and even individuals. Disposal of brine water is made either directly or indirectly into the sea, sewage system, poor land, channels, wadies, etc. Brine constituents have an adverse impacton the surrounding environment, e.g., sea life, soil, wastewater treatment plants and the groundwateraquifer. The lack of real environmental impact assessments, especially for mid- and home-scale units may lead to a deterioration of the environment. The fragmentation of the responsibilities of water desalination, distribution of desalinated water and the disposal of brine water suggest that urgent action should be taken (e.g., legislation or establishment of a supervisory body). In other words, strict policies and management actions are to be taken in order to alleviate the health and environmental impact of an important and uncontrolled new system.
Salinity is one of the major problems that the coastal region of Bangladesh has been facing over ... more Salinity is one of the major problems that the coastal region of Bangladesh has been facing over the last couple of decades. Due to sea level rise, frequent natural disasters, changes of climate patterns and man-made alteration of natural settings, the situation is becoming more vulnerable day by day. It has also been observed th
Electrodialysis (ED) is applied in Japan for seawater concentrating to ca. TDS 200 followed by th... more Electrodialysis (ED) is applied in Japan for seawater concentrating to ca. TDS 200 followed by thermal concentration and salt crystallization. A partially desalinated water (ED diluate) is obtained at the same time. Its further desalination for potable water production may be considered to decrease costs of ED by obtaining two valuable products instead of mere salt. Univalent ion permeable ion-exchange membranes are however applied in ED process and as a result the contents of calcium, magnesium and sulfate ions in diluate are relatively high (in relation to chloride), which makes any further processing difficult. Electrodialysis reversal (EDR) may overcome these shortcomings. The salinity of partially desalinated water is as high as TDS 22.9. If dual-purpose desalination-salt production electrodialysis concern is high degree of desalination, which is however necessary, this implicates many problems in the ED process that are the result of major differences in ED concentrate and diluate concentrations and the small conductivity of potable water grade diluate. Electrodialysis of seawater was investigated in a two-step stand with ED-MSF-Crystallization system being the first stage. Univalent ion permeable Tokuyama Co. ACS and CMS membranes were applied in the first step and normal grade CMV, AMV Asahi Glass membranes in the second step (for the first step diluate treating). ED stack developed by the author and equipped with 0.19 mm spacer was applied. A single-pass low residence time mode of operation was applied to avoid gypsum crystallization in the second step ED concentrate. The first step diluate containing, in g/L, Ca2+—0.38, Mg2+—1.26, Cl−—4.08, SO42-—2.78 was treated by EDR yielding 90% recovery. Potable water grade EDR diluate was obtained. No gypsum crystallization in the EDR concentrate was observed despite its 360% saturation. The total water recovery of ED-MSF-crystallization system is equal to 90%. As there are two valuable products in the described process, the cost of each of them is obviously related to their selling price. IF $30 per one ton of salt is assumed, the potable water cost is estimated to be only $0.44/m3.
A two-year research program on solar photovoltaic desalination of brackish water by electrodialys... more A two-year research program on solar photovoltaic desalination of brackish water by electrodialysis was carried out in the remote area of Fukue City, Nagasaki Prefecture. The standard of water produced was found suitable for drinking, the quantity exceeded expectations, and the system was found reliable for practical use.
The potabilization process of desalinated water used at the Royal Commission power and water comp... more The potabilization process of desalinated water used at the Royal Commission power and water complex located in Madinat Yanbu Al-Sinaiyah (MYAS) consists of four unit operations, namely liming, carbonation, chlorination and aeration. The water is remineralized by adding hydrated lime and carbon dioxide through the liming and carbonation step, thereby raising hardness, alkalinity, pH and dissolved solids content. The chlorination is carried out by the injection of chlorine gas to disinfect the water and eliminate bacterial growth. The aeration is done to replace oxygen driven out by the multi-stage flash distillation process, thereby improving the taste of the water. This paper describes the potabilization facilities and discusses the plant operating data with water quality parameters of the potabilized water.
Some countries (e.g. Korea, China, India, Pakistan, Japan) were forced to adopt the nuclear energ... more Some countries (e.g. Korea, China, India, Pakistan, Japan) were forced to adopt the nuclear energy option to generate electric power Ep (by nuclear power plants NPP) and desalt seawater D (by nuclear desalination ND) due to the rising cost of fossil fuel and its insecure supply. The increase of fuel oil consumption and cost (more than $100 per barrel) motivate other countries, even oil exporting countries, to look for cheaper alternatives to produce both Ep and D. The locally consumed oil in these countries is deducted from its reserves and/or decreases its income. In addition, the green house gases (GHG) emission resulting from burning fossil fuel contributes to global warming and adversely affects the environment. In Kuwait and other Gulf cooperation countries (GCC), huge amounts of fuel (oil and natural gas) are consumed by co-generation power desalting plants (CPDP) to produce Ep and D. The use of this fuel to produce Ep and D cannot be expanded indefinitely as the oil supplies are finite and dwindling. Thus, less costly and sustainable new sources of energy such as solar, geothermal, wave, and wind energies are explored. The share of usage for these sources are so little and their wide expansions in the next decade are doubtful. Presently, nuclear energy is economically viable, and is a large-scale alternative to fossil fuel for generations of Ep and D. The use of nuclear energy (NE) raises many concerns about its safety, high capital cost, and radiation effects on surroundings and workers in the short and long term. The question raised should not be either to accept NPP or not, as it may be the only choice we have. The real questions are: how and when NPP will be inherently safe, economical, and when can it be applied safely in countries at different stages of development. Nuclear energy can present a sustainable way to produce Ep and D if its standing problems can be resolved. It can become a significant option for meeting the future world energy needs at low cost and in an environmentally acceptable manner. In this paper, the prospects of using nuclear cogeneation power desalting plants (N-CPDP) in Kuwait and some of the GCC are discussed. The conditions required to build NCPDP and its associated problems are outlined and discussed.
The IDAE is a public entity of the Ministry of Industry and Energy which belongs to the Departmen... more The IDAE is a public entity of the Ministry of Industry and Energy which belongs to the Department of Energy and Mineral Resources. Its objective is to improve energy efficiency in the use of energy in the different consumer sectors and to promote production and consumption of renewable energies. The work of the IDAE in the different consumer sectors is derived from action planned in the Energy Saving and Efficiency Plan (ESEP) of the National Energy Plan 91/2000 and from strategies identified in the New Promotion of Spain's Energy Saving Policy, which includes thinking ahead to promote activities so that consumer sectors will be able to avoid having to take costly corrective measures - where feasible - in the future. The activities to promote energy efficiency are therefore of particular interest in the new desalination sector which is already working on a large scale in Spain.
The cost of producing electricity with OTEC plants is compared to the cost of electricity produce... more The cost of producing electricity with OTEC plants is compared to the cost of electricity produced with fossil-fueled plants to establish scenarios under which OTEC could be competitive. In the case of OTEC, when appropriate, the cost of electricity is estimated with credit for the desalinated water produced. Two generalized markets are considered:
Even though the volume of the earth's water is vast, less than 10 million of the 1,400 million cu... more Even though the volume of the earth's water is vast, less than 10 million of the 1,400 million cubic metres of water on the planet is of low salinity and suitable for use after applying conventional water treatment alone. The other 97.5% of the water on our planet is to be found in the oceans, where it is officially classified as seawater.Desalination provides a means of tapping this resource, and over the last 30 years, seawater desalination technology has made great strides in many arid regions of the world, such as the Middle East and the Mediterranean, and is starting to be considered viable even in cooler regions of the world not traditionally associated with water shortage (the UK for example.)Filtration + Separation looks at the subject of desalination, starting with an overview of the current situation; we ask some experts in the field to point out the reasons why desalination has now become such an acceptable worldwide water treatment phenomenon (Factors behind the growth in desalination - below, and pages 15 – 18.)On page 19, we briefly examine the different technical aspects of desalination available today (Desalination – the basics.)We then publish two case studies; the first looks at Israel, which has embarked upon a large-scale seawater desalination program, most notably the Ashkelon project – a 100 million m3/year SWRO desalination plant (Case study: assessing the need for, and costs of, seawater desalination in Israel - pages 20 and 21.)The second looks at Pretreatment - a vital part of any desalination process – using the US, California, Carlsbad seawater desalination pilot plant as an example (Case study: Pretreatment at Carlsbad seawater desalination pilot plant – pages 22 – 25.)
Vacuum desalination is a process by which water is vaporized at a lower temperature when subjecte... more Vacuum desalination is a process by which water is vaporized at a lower temperature when subjected to vacuum pressure. The heat energy requirement for desalination using a distillation process can be brought down by reducing the boiling temperature. The boiling temperature of seawater can be lowered to as low as 400°C by the creation of a vacuum. Using waste heat from a steam turbine, a pilot study was conducted in the laboratory to investigate the feasibility of using a vacuum desalination process for water supply. The treatment system is designed to minimize the heat requirement. Initially, the seawater is converted to a wet steam in a saturated vapour heater. This vapour heater receives heat from the superheated steam which is due for condensation. The dry component of the wet steam is heated to superheated condition by a superheated vapour heater. This superheated vapour heater receives heat from the waste heat from a steam turbine. Superheated vapour is used to covert incoming seawater to wet steam and then be condensed as the product of the system for potable use. The investigation shows that a vacuum desalination system using turbine exhaust waste steam is possible and has several advantages. Seawater can be boiled at a lower temperature and thus save in energy consumption. Based on experimental results, water boils at 40–90°C at the corresponding vacuum pressure of 0.1–0.7 bar, respectively. The consumption of heat from the waste steam is minimized as the superheated vapour is used to heat the influent seawater. Most of the heat from the waste heat is required to compensate for the heat losses in the system. The energy efficiency of the system depends very much on decreasing the heat losses from the system. It is possible to use nonconventional energy sources such as lower pressure waste steam for vacuum desalination. Hard scale formation in the system can be minimized as scale forming is the major problem in a high temperature distillation process. The qualities of distillates are excellent.
When chemical disinfection is applied before or after desalination systems, compounds may be form... more When chemical disinfection is applied before or after desalination systems, compounds may be formed that pose potential risks to the health of human and aquatic organisms or impact aesthetic quality of drinking water. The formation and speciation of disinfection by-products (DBPs) in desalination systems is affected by the elevated concentrations of bromide and iodide in seawater and desalinated product water. To gain insight into DBPs likely to be formed in desalination systems, DBP studies conducted in saline source waters, coastal power stations and existing desalination systems are reviewed. Chlorination is the most common disinfectant used in current desalination systems, with chloramines and chlorine dioxide gaining more popularity for disinfection of desalinated water. When seawater or reverse osmosis permeate is chlorinated, bromoform (CHBr3) and brominated haloacetic acids (e.g. monobromoacetic acid, dibromoacetic acid, bromochloroacetic acid) are found to be the prevalent DBP species. Under conditions typically encountered in desalination systems, concentrations of these DBPs in the product drinking water are below levels of concern set by regulating agencies. Less information is available on the formation of other haloorganic DBPs in desalination plants. Among DBPs identified in saline drinking waters, haloacetonitriles (HANs), mutagen X compounds (MX), halonitromethanes (HNMs) and cyanogens bromide (CNBr) pose potential concerns, especially when desalinated waters are blended with organic-matter rich source waters.
Bromine and iodine have been utilized in this study as heat generating media for the enhancement ... more Bromine and iodine have been utilized in this study as heat generating media for the enhancement of overall efficiency of the simple conventional basin type solar stills.Results of the experimental work showed that the solar still of bromine medium has a higher efficiency than that of iodine medium. However, both stills have significantly higher efficiencies when compared with that of the conventional one. Also, the results showed that the productivity of the still of bromine medium is about 65% greater than the conventional still. For an iodine medium still the productivity is about 42% greater than the conventional one.
Salinity is one of the major problems that the coastal region of Bangladesh has been facing over ... more Salinity is one of the major problems that the coastal region of Bangladesh has been facing over the last couple of decades. Due to sea level rise, frequent natural disasters, changes of climate patterns and man-made alteration of natural settings, the situation is becoming more vulnerable day by day. It has also been observed th
The paper presents an attempt to assess sustainability of desalination plants for water productio... more The paper presents an attempt to assess sustainability of desalination plants for water production based on resource, environmental and economic indicators. Four types of desalination plants are taken into a consideration: single MSF, dual purpose MSF, RO with local energy consumption and RO with PV electric energy production. The analysis is based on data from desalination plants in Gulf countries. In particular, it reflects water production demand and energy sources used for the individual plants. The decision-making procedure in the sustainability assessment of desalination plants is based on the multi-criteria evaluation under uncertainty of complex systems expressed by the General Sustainability Index. Evaluation of different cases reflecting priority of the criteria for evaluation has led to the selection of options, which are in compliance with respective criteria.
Desalination market growth has triggered significant development in SWRO membrane and process dev... more Desalination market growth has triggered significant development in SWRO membrane and process development and the new extra high rejection and ultra low energy membranes from Dow, FILMTEC™ SW30XHR-400i and SW30ULE-400i, as well as the internally staged design concept, have been validated in extensive field testing and various commercial plants over the recent years and are now commercially available. These solutions from Dow can be used to increase membrane flux and system recovery and / or to reduce feed pressure. This yields capital cost and /or energy savings. These savings have been assessed in 4 different situations / geographies, using a thorough and validated cost model. These geographies are South Pacific (Australia), Persian Gulf (Saudi Arabia), with very different feed water qualities (in terms of feed salinity and temperature range) and product quality requirements (in terms of bromide, boron and salinity). Depending on the cost savings route chosen, there are strong differences in the consequences with regards to size of the RO stage (17-26% smaller), size of the pretreatment (9-12% smaller), and/or the feed pressure (2-6 bar lower). These cost savings are in the range of US cent 0.4-4.1/m³ water produced. This is equivalent to 0.7-6.5% water cost saving. Considering that these considerable cost savings are readily available since 2008 from Dow Water Solutions, the industry should start to significantly benefit from these in the coming years.
Cyprus suffers from droughts, which sometimes continue for a number of consecutive years and crea... more Cyprus suffers from droughts, which sometimes continue for a number of consecutive years and create serious water shortage problems. In the past the efforts of the Government were towards the erection of dams, but the water management system dependence on the weather was not alleviated. The first reverse osmosis desalination plant was erected 5 years ago. Three more plants, one of the same capacity and two with half, are planned in the near future. The Government believes that with the completion of all these plants, the water shortage problem will be solved permanently. As Cyprus has no fossil fuel resources, it relies entirely on fuel imports for its energy needs. It is estimated that 25% of the price of the desalinated water is attributed to the energy cost. This is a parameter that should never be underestimated as all plants are powered with electricity, which is produced entirely from imported fuels. The only natural resource of Cyprus is solar energy, which is abundantly available. It is thus sensible to develop desalination systems which can even partly be powered from solar energy systems, either through a combination of photovoltaics and the existing or planned reverse osmosis systems or from a combination of solar thermal and distillation evaporators. The first one is considered in this paper. These are all mature technologies and thus the financial risk from their implementation is minimum. The added benefit from the adoption of renewable energy sources, besides the issues related to environmental protection, is that they reduce dependency on imported fuels.
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