RENEWABLE DESALINATION IN QATAR

US - Denmark Summer Workshop on Renewable Energy August 21, 2013

Authors: Magdalena Brum Anthony Palavi

Tyler Lee Rebecca Quinte

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Contents

1 Abstract Acknowledgements (e.g. people who provided you with information important to your project) Table of Contents 2. List of Tables 3. List of Figures Table of Nomenclature 4. Executive Summary (not more than 2 pages with representative graphic of results. Briefly state conclusions.) 5. Introduction and Problem Statement 6. Background & literature review

6.1 Water Desalination in Qatar 6.2 Multi-stage Desalination

6.3 Reverse Osmosis 6.4 Integrated Solar Combined Cycle MED Desalination

6.5 Brine Waste 6.5.1 Alternative Use for Brine 6.6

7. Methodology 8. Results Discussion and Conclusions References (complete citations so anyone reading the report can also find the same reference you used. Make sure all references included are cited in the report. If using a web url, give the date of access in parenthesis.) Appendix

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Abstract By comparing different types of desalination this research’s objective is to find the optimal method for desalting water in Qatar. There are three different types of desalination in this study: multi-stage flash (MSF), reverse osmosis (RO), and Integrated Solar Combined Cycle MED Desalination (ISCC MED). Researching the advantages and disadvantages of each method of distillation and modeling the different types of desalination against each other with a baseline output of fresh water the simulation should obtain an economical solution. An assessment of the desalination plant’s discarded brine pollution is studied, and an economic solution to the wasted brine in Qatar.

Executive Summary Qatar is a country experiencing heavy strains on its energy and water supply, coupled with increasing demand and significant environmental impact. To address these issues, its national government has set targets to reduce electricity consumption by 20% and water consumption by 35% by 2030. This report will explore the use of multistage flash, reverse osmosis, and solar energy desalination technologies for potential use in Qatar, as well as inspect how brine waste from desalination can be utilized for salt production. A feasibility analysis will demonstrate the different benefits and efficiencies of desalination systems and their waste product, brine, which have the potential to help Qatar achieve its goals, alleviate expanding demand, and save the country’s natural gas resources. Desalinated water in Qatar is produced in natural gas-based cogeneration power plants (CHP) that use either simple gas turbines cycle or combined cycles. These cycles generate electricity and provide thermal energy (as steam) to a multistage flash (MSF) desalting system. MSF has high-energy consumption (20 kWh/m3), so an alternative system for the MSF process should be able to provide the same amount of fresh water and electricity than the current CHP plants. Additionally, since on of the major factors affecting the choice of desalting system is the consumed energy and its production cost, serious consideration should be given to the type and cost of energy to be used. Based on a preliminary literature review, reverse osmosis (RO) and solar energy (both integrated solar combined cycle based on concentrated solar power and solar PV for electricity production) appear to be promising alternatives for MSF desalination. Multi-stage flash distillation is one of the most trusted desalination techniques, but it has a high-energy consumption and outputs a large amount of brine for a small fraction of fresh water. In Qatar, MSF has been chosen over other types of desalination because more reliable than other desalination methods and it is unaffected by the high salt levels in the Persian Gulf. Most of the desalination plants in Qatar are MSF with a CHP component.

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Reverse osmosis (RO) is currently the most energy efficient, reliable, and cost effective technology for seawater desalination, becoming one of the most popular choices outside of the Middle East for desalination plant type over the past two decades. In a salt water reverse osmosis (SWRO) system, feed seawater at about 35ºC is pressurized to create a net driving pressure across a semipermeable membrane, usually a robust thin-film composite membrane; a brine waste is discharged at a minimum of 65,000 once the process is over. Despite SWRO’s popularity, in the Gulf countries the accessibility of natural gas has made thermal desalination the standard, despite the fact that the use of SWRO instead of thermal desalination technologies in Qatar could reduce the country’s CO2 emissions from 3.564 to 0.891 million tons per year, seawater intake from 8.4 Mm3/d to 3.6 Mm3/day, and brine discharge from 7.2 Mm3/d to 2.4 Mm3/day. RO is favorable to MSF since no heating or phase change is necessary (Karaghouli and Kazmerski), overall recovery ratios are 30% to 50% (Karaghouli and Kazmerski), and RO requires up to 4 to 7 kWh of electricity per cubic meter of water. Solar energy can directly or indirectly be harnessed for desalination. Indirect solar desalination methods involve two separate systems: the collection of solar energy, by a conventional solar converting system, coupled to a conventional desalination method. In indirect systems, solar energy is used either to generate the heat required for desalination and/or to generate electricity that is used to provide the required electric power for conventional desalination plants such as multi-stage flash (MSF) or reverse osmosis (RO) systems. Concentrating solar thermal power technologies are based on the concept of concentrating solar radiation to provide high-temperature heat for electricity generation within conventional power cycles using steam turbines, gas turbines, or Stirling and other types of engines. For concentration, most systems use glass mirrors that continuously track the position of the sun. The four major concentrating solar power (CSP) technologies are parabolic trough, Fresnel mirror reflector, power tower, and dish/engine systems. Brine is a waste product from desalinated water, and if not properly managed, could cause environmental and sociological damage. It is a serious concern within the Persian Gulf, given that Qatar alone possesses a desalination capacity of 300,000 cubic meters per day. Additionally, the cost of brine disposal can range anywhere between 5% and 33% of the total desalination system’s cost. In this report we have developed an Environmental Impact Assessment (EIA) to present a brief overview about some key environmental effects that brine waste has on the environment and its aquatic life, focusing on fossil fuel demand, desalination pollutants, resultant thermal pollution, and quality of brine waste content. Moreover, as an alternative to dumping, this report will examine the economic feasibility of table salt production from brine waste, to be sold for commercial use. To develop our feasibility analysis, we first decided to choose a plant with a capacity of 200,000 cubic meters per day. This was a number based on the average sized Qatar plant. After choosing

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this figure, we used an Excel-based software freely provided by the International Atomic Energy Agency (IAEA), the Desalination Economic Evaluation Program (DEEP), which can be used to analyze performance and cost of various types of plants. In regards to the MSF and RO plants, the program had default features in place, with most of the technical data correlating with the data we found in literature. The necessary economic parameters were developed from our own calculations. We were also able to model a SE plant with a few adjustments to the default plants. From this modeling, we found that as expected, both RO and IS MED show a significant reduction in the fossil fuel requirement when compared to the BAU MSF plant. However, under the described set of assumptions, RO appears to be a better alternative in terms of LCOE and LCOW than ISCC MED, due to the significantly higher upfront costs of the solar array. The two factors economies of scale and technology development can increase the future competitiveness of the solar option. Since CSP plants are feasible above 50MW, which was the size considered for this study, an increased CSP scale could decrease the effect on the levelized costs of electricity and water. However, it is necessary to model such scenario in order to make proper conclusions on the effects of solar array scale. Further technology development will assist in lowering the cost of solar technology.

1. Introduction and Problem Statement Qatar is facing substantial challenges relating to the management of water and energy resources. Both resource systems are increasingly stressed by expanding demand (15% annual growth for the last five years), diminished supply, and environmental degradation. Qatar’s national government has announced plans to reduce electricity consumption 20% and water consumption 35% by 2030. Three-fourths of municipal water supply comes from desalinated seawater obtained from a natural gas-based multistage flash (MSF) process, which is energy intensive and costly. Thus, deploying a more energy efficient desalting system can help alleviate the water and energy issue, while saving a significant amount of natural gas, the nation’s main source of income. Given these factors, the scope of this report will encompass a comparative analysis of the environmental impact of MSF, reverse osmosis (RO) and integrated solar MED (IS-MED) desalination technologies, under the assumption of equal outcomes of fresh water and electricity production. Additionally, production and disposal of brine waste is an integral part of the desalination process. However, improper brine management adversely affects the marine environment and organisms. An Environmental Impact Assessment (EIA) showed temperature spikes as large as 57°C at brine output plumes, chemical discharges and emissions of air pollutants from energy inputs. Also, a proposal suggested using natural evaporation method to produce salt from brine waste. Economic & market analysis showed in 2010 Qatar imported $24.5 million (usd) of salt;

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capacity feasibility showed Qatar has 12,580 sq km of open land for salt production. Therefore, the proposal could potentially benefit the environment and diversify the business sector in Qatar.

2. Background & literature review

2.1 Water Desalination in Qatar Qatar is producing about 150 million cubic meters of desalinated fresh water annually, which accounts for approximately “three-quarters of the total water demand” of the region (Danoun, 2007). According to The World’s Water, an online resource with an invaluable collection of water-related data tables, Qatar had about 560,764 cubic meters/day of total installed desalination capacity between the years 1945 - 2004 (Danoun, 2007). Desalinated water in Qatar is produced in natural gas-based Cogeneration Power Plants (CHP) that use either simple gas turbines cycle or combined cycles. These cycles generate electricity and provide thermal energy (as steam) to a multistage flash (MSF) desalting system, an energy-intense process. The rapid economic growth in Qatar is leading to a substantial increase in electric power and desalted seawater demands, which results in a significant stress on the environment due to fossil fuel combustion and brine waste disposal. On one hand, natural gas combustion results in emission of air polluting gases as well as CO2. On the other hand, concentrated brine discharged from the desalination plants pollutes the marine and terrestrial environment. This brine has higher temperatures than seawater and is mixed with chemicals such as chlorine. Thus, to protect the environment and to make the DW more sustainable potable water source, renewable energy and more energy-efficient desalting systems compared to MSF system should be used for desalting seawater (Darwish 2012). Since the BAU is to integrate desalination plants with a CHP plant, an alternative system for the MSF process should be able to provide the same amount of fresh water and electricity than the average CHP plants existing in the country. Based on a preliminary literature review, reverse osmosis (RO) and integrated solar multi-effect distillation (IS-MED) appear to be promising alternatives for MSF desalination in Qatar.

One of the main factors affecting the choice of desalting system is the consumed energy (thermal or mechanical, or both) and its production cost. The energy cost represents a good portion of the final desalted water unit cost, and thus serious consideration should be given to the type and cost of the energy to be used. (Darwish 2012, Shatat 2013).

2.2 Multi-Stage Flash Desalination

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Figure [-_-] In the MSF, brine is heated before being exposed to a low pressure causing its partial evaporation by flashing in successive stages. In figure [-_-] it shows that when pressure goes down the boiling temperature also decreases. This property is fundamental of MSF and aids in the distillation process. Each state of MSF has lower pressures in each stage. The flashed vapor is condensed in a condenser mounted in the upper part of each stage where the brine is primarily pre-heated. The brine is finally heated in a brine heater before entering the first stage for partial evaporation by flashing. The brine is moved from one stage to the next to conserve the heat. Distillation of seawater is the oldest method of retrieving fresh water from salt water. It has been known for thousands of years. Distillation is when water is heated up and changed into steam from liquid leaving behind other particulates and additives like salt. Currently, the majority of desalination is distillation specifically MSF because of two reasons the scalability and it's independence from salt content (Young 1971). Most of the desalination in the world is done in the Middle East where the seawater salinity levels are high. One major flaw of MSF desalination is that its brine output is one of the highest in desalination technology. For every cup of water you will get six cups of brine as well. The amount of brine that’s released from the MSF plant is still pretty diluted, and most MSF plants release the used brine back into the seawater input (Veerapaneni 2007). MSF(multi stage flash) desalination only has a brine 1.2 times the amount as seawater, but other desalination methods like reverse osmosis might have brines with greater parts per million of salt than MSF desalination. Thermal multistage desalination in the Persian Gulf isn't affected by the high salinity levels of the sea water which has around 45000 parts per million of salt. Average seawater salt content is 35000 ppm. Reverse osmosis is more expensive when the salinity content of the water is higher. Desalinating brackish water like sea water found in the Baltic Sea, which has around 7000 ppm of salt, is more favorable for reverse osmosis because the lower the salt content the more efficiently the RO can run. MSF distillation has a high energy demand and runs almost independently of how much ppm of salt there is in the water (Probstein 1973). The amount of water processed is proportional to the energy used. However, the downside to being unaffected by salt ppm is that the same energy needed to desalinate seawater with a content of 45000 ppm and 7000 ppm is relatively the same (Veerapaneni 2007). One of them main requirements of MSF is a heat source. Most of the heat needed for a MSF plant comes from an electricity generating turbine. The steam is transported from the gas turbine

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plant to the desalination plant. In places like Saudi Arabia and other Middle Eastern countries it made sense to use combined heat and power for desalination. Ten megawatts of gas turbine power can help produce 1 million gallons of fresh water a day with a MSF plant (Reuther 2000). The needed heat for a MSF plant can be subsidized with heat that is produced when making energy. This makes a MSF plant more efficient and cuts down the cost.

Source: Al-Karaghouli (2009)

MSF require heat at 70-130°C and use 25-200 kWh/m³,

2.3 Reverse Osmosis Reverse osmosis (RO) is currently the most energy efficient, reliable, and cost effective technology for seawater desalination (K&K). Over the past two decades, the majority of desalination plants worldwide have utilized RO technology, and there are many future plants that will incorporate the technology as well. However, in the Gulf countries, due to the accessibility of fossil fuels, the standard is thermal desalination. Thermal desalination plants consume significant amounts of thermal and electric energy, which involve significant greenhouse gas emissions (Elimelech), seawater intake, and brine discharge; so significantly that the use of SWRO instead of thermal desalination technologies in Qatar could reduce the country’s CO2

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emissions from 3.564 to 0.891 million tons per year, seawater intake from 8.4 Mm3/d to 3.6 Mm3/day, and brine discharge from 7.2 Mm3/d to 2.4 Mm3/day (Darwish). In a salt water reverse osmosis (SWRO) system, feed seawater is pressurized to create a net driving pressure across a semipermeable membrane. Once the feed water passes through the membrane, it has been desalinated; the remaining feed water continues along the pressurized side as brine. Reverse osmosis (RO) systems are composed of four main processes: pretreatment, a relatively energy intensive process in which feed water is treated to protect RO membranes from fouling; pressurization of feed water; separation, in which the membrane allows water to pass through while retaining dissolved salts and discharging a portion of this brine; and posttreatment, in which the desalinated product water undergoes pH readjustment and degasification, to be used for drinking water or stored for later use (Karaghouli and Kazmerski).

Figure X. Schematic diagram of an RO system (Karaghouli and Kazmerski). As such, the two most essential components of the system are the high-pressure feed pump and the RO membranes (Karaghouli and Kazmerski). Most RO desalination plants use robust thin-film composite membranes, and are capable of rejecting 99.6-99.8% of dissolved salts in seawater feed. Composed of two different polymer layers that can be optimized separately, they have higher intrinsic water permeabilities and are stable over a greater pH range than the first commercially viable cellulose-based membranes; the different layers also yield higher salt rejections and water fluxes. However, a disadvantage of thin-film composite membranes is that they are prone to fouling; this negatively affects process performance (Elimelech and K&K). Reverse osmosis is favorable to MSF since no heating or phase change is necessary (Karaghouli and Kazmerski), but energy requirements increase with increasing salinity or water recovery (Elimelech). Since the specific electricity consumption of the plant needs to be kept as low as possible and overall recovery ratios are 30% to 50% (Karaghouli and Kazmerski), large-scale SWRO plants use energy-recovery turbines that recover some of the pumping energy. RO requires up to 6 kWh of electricity per cubic metre of water (depending on both processing and its original salt content), and there is a thermodynamic limit on the energy demand for desalination, so future research to continue to improve energy efficiency should have a strong focus on pretreatment and posttreatment stages (Elimelech).

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2.4 Integrated Solar Combined Cycle MED Desalination Solar energy can directly or indirectly be harnessed for desalination. When integrated with conventional desalination systems, indirect methods are used. Indirect solar desalination methods involve the collection of solar energy, by a conventional solar converting system, coupled to a conventional desalination method. The solar energy is used either to generate the heat required for desalination and/or to generate electricity that is used to provide the required electric power for conventional desalination plants such as multi-stage flash (MSF) or reverse osmosis (RO) systems. (Qiblawey 2008). Concentrating solar thermal power technologies are the current choice in many countries in the Gulf region1, thus the one to be consider for this analysis. These systems concentrate solar radiation to provide high-temperature heat for electricity generation within conventional power cycles using steam turbines. The best-known solar thermal desalination combination is solar multi-effect distillation (MED) (Darwish, 2012). From an energy perspective, the main supply to the desalination plant is a large thermal input, as well as some auxiliary electricity required for pumping.

Figure 1 - Schematic diagram of solar-based MED

2.5 Desalination Process Waste: Brine

1 Shuaiba North in Kuwait, JabalAli and Ali in UAE.

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Brine is a waste product from desalinated water, and if not properly managed, could cause environmental and sociological damage. Studies taken at various institutions around the world, such as The Ocean Technology Group (OTG) at the University of Sydney, Australia, concur that “using desalination as a water resource would have considerable environmental impacts to the surrounding area including the ecosystems” (Danoun, 2007). Hence, this Environmental Impact Assessment (EIA) intends to present a brief overview about some key environmental effects that brine waste has on the environment. This EIA will be based on the following features: fossil fuel demand and quality of brine waste content (salinity content, quantity output, temperature range). Lastly, to avoid dumping in the ocean, table salt production from brine waste will be studied in order to assess the economic feasibility for alternative uses for brine waste. Salinity content in seawater plays an important role in the size and growth of aquatic organisms. Any significant changes to salinity content could influence the life expectancy of aquatic animals, their population density growth rate, and breeding of species (Danoun, 2007). Brine waste is highly concentrated, containing double the salt concentration of input seawater (Ibrahim, 1987), with an estimated salinity content of 64-70 parts per thousand (ppt) (Danoun, 2007). Given Qatar’s total desalination capacity of 300,000 m3/day, subsequent millions of tons of brine are discharged into the Persian Gulf each year (Ibrahim, 1987). Chemical discharges from desalination plants have been shown to greatly disrupt the aquatic life. In 2008, the Institute for Chemistry and Biology of the Marine Environment (ICBM) at the University of Oldenburg conducted an “Environmental impact and impact assessment of seawater desalination technologies” which examined the effect desalination plants had on the marine environment. These effects include chemical discharges into the ocean, emissions of air pollutants from the energy demand of the processes. Some of the chemical materials found in seawater used throughout various stages in the desalination process (e.g., blot clearing, cleaning stages) include: Sodium hypochlorite (NaOCl), Ferric chloride FeCl3 or aluminum chloride AlCl3, Sulfuric acid H2SO4 or hydrochloric acid HCl, Sodium bisulphate NaHSO3, Crystalline acid EDTA (ethylenediaminetetraacetic acid) C10H16N2O8 and Citric acid C6H8O7 (Danoun, 2007). Temperature changes also produce an impact on marine ecosystems. Brine discharge can act as a catalyst for oceanic temperature changes, referred to as “thermal pollution,” where temperature levels increase higher than the ambient ocean water temperature (Danoun, 2007). In areas of thermal pollution, temperatures spikes can be as large as 57°C at the output of the plume discharge (Danoun, 2007). Figure 4 shows difference of temperature in ocean waters and around brine discharging stations at saltwater desalination plants. Considerable changes in temperature are apparent, where the top graph shows higher fluctuations (between 10 and 40°C) in comparison with mean oceanic temperatures. Figure 4

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Source: Jenkins et al, 2005 Flora and fauna on both the macro and micro scales have been shown by marine biologists to have been affected with regard to behavioral and life-cycle patterns from thermal pollution (Danoun, 2007).

3. Methodology This study will consider an average sized MSF plant producing both power and fresh water as the business as usual (BAU) technology. Reverse osmosis and solar MED producing the same amount of fresh water and electricity will be analyzed in terms of their inputs and production costs and will be compared to the BAU. The analysis will address the following research questions: Can RO and IS-MED technologies reduce the environmental impact of the desalination

sector in Qatar in terms of seawater and fossil fuel requirement for equal outcomes of electricity and fresh water?

How do LCOE and LCOW change with the technologies considered? What are the characteristics of the brine waste for each of the technologies considered? Is there an economically feasible alternative use of brine to avoid dumping it to the Gulf? In order to select an appropriate size for the CHP desalination plants, the capacities of the newest combined cycle desalination plants in Qatar were considered.

Table 1- Capacities of newest combined cycle desalination plants in Qatar

Plant MW MGD MW/MGD

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name RAF B 609 33 18 RL A 756 40 19 RL B 1025 60 17

Based the above plants, the average plant capacity to be considered is: Electric power - 950 MWe Fresh water - 53 MGD = 200,000 m3/d

3.1 Desalination Economic Evaluation program (DEEP) The Desalination Economic Evaluation Program (DEEP) is a tool made freely available by the International Atomic Energy Agency, which can be used to evaluate performance and cost of various power and water co-generation configurations (IAEA, 2007). The program allows designers and decision makers to compare performance and cost estimates of various desalination and power configurations. Desalination options modeled include MSF, MED, RO, and hybrid systems, and power options include nuclear, fossil, and renewable sources. Co-generation of electricity and water, as well as water-only plants, can be modeled. The program also enables a side-by-side comparison of a number of design alternatives, which helps to identify the lowest-cost options for water and power production at a specific location. Data needed include the desired configuration, power and water capacities, as well as values for the various basic performance and costing data. The DEEP performance models cover both the effect of seawater salinity and temperature on recovery ratio and required feed water pressure.

3.2 Model assumptions The basic model parameters used for the analysis are summarized in the tables below. Table 2 - General modelling parameters

Parameter Value Source

Gulf seawater salinity 45000ppm based on average conditions for the Persian Gulf (Kämpf 2006).

Gulf seawater temperature 30 C based on average conditions for the Persian Gulf

(Kämpf 2006).

Natural gas price 3.368 $/mmBTU based on international prices as of 8.16.2013 (Index Mundi)

Natrural gas CO2 emission coefficient

53.1 kg CO2/mmBTU EIA

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Table 3 - Technology-specific model parameters

3.3 Model flow diagrams Using the parameters indicated above, the flow diagrams for the three technologies were constructed.

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Figure 2 - MSF-CC Plant Flow Diagram

Figure 3 - RO-CC Plant Flow Diagram

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Figure 4 - IS-CC-MED Plant Flow Diagram

4. Results

4.1 Input comparison The main parameters considered for the technology comparison, are the natural gas requirement and the levelized costs of both electricity and fresh water. The table below summarizes the results.

Natural Gas (mmBTUX10^6) LCOE ($/kWh) LCOW ($/m3)

MSF-CC 72 0.052 5.35

RO-CC 68 0.052 4.14

IS-CC-MED 66 0.122 4.7

4.2 Cost distribution comparison The relative cost share for the different plants is shown in the graphs below.

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4.3 Alternative Use for Brine Considerable amounts of brine waste are disposed of during the desalination process, especially on a production scale of 150 million cubic meters per year of freshwater (Danoun, 2007). Current brine disposal options for seawater desalination plants include: discharge to surface water, wastewater treatment plants, deep well injection, land disposal, evaporation ponds, and mechanical/thermal evaporation. Given the appropriate process, “brine can yield ... salt, sodium chloride” (Ibrahim, 1987). Therefore, we are proposing the production of Crystalline salt from brine waste, which could be sold for commercial use. In addition, we will present brief technical and economical feasibility assessments of salt production from brine waste in Qatar. Conventional methods for heating brine waste involve using thermal evaporation, which can be an energy intensive process (Arnal, et al., 2005). Nevertheless, according to the Chemical and Nuclear Engineering Department (CNED) at the Polytechnic University of Valencia, companies located in areas with warm conditions can use environmental or “natural” evaporation methods (Arnal, et al., 2005). One drawback noted with the natural evaporation method is that the process requires “large earth extensions since the productivity of the process is quite low (around 4 L.m-

2.d-1)” (Danoun, 2007). However, Qatar has approximately 12,580.7 sq km (7,817.28 sq mi) of arable and undeveloped land that could provide an adequate amount of open space for salt production (Appendix D). Economic considerations are also important assessments to make for this analysis. In general, brine management and plant location are two essential factors to consider with saltwater desalination. The cost of disposing of brine “ranges from 5 to 33% of total cost of desalination” (Arnal, et al., 2005). Seawater desalination plants can easily dispose their brine into coastal waters using “pipes or submarine emissaries,” whereas inland plants are limited with an expensive and less-optimal set of options (Arnal, et al., 2005). However, Qatar does not have this problem because the country is located near the ocean. Moreover, given their warm climate and

Figure 5 - Comparative cost share between technologies

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fresh-water production capacity of over 300,000 m3/day, Qatar is in a unique position with regard to salt production from brine. Qatar’s entry into the salt market could help domestic business development, attract entrepreneurs and create jobs. Figure 5 shows that in 2010 Qatar imported $24,410,025 (USD) of salt, including table salt. This figure is astounding because that same year millions of tons of useful brine waste had been dumped back into the ocean. Equally incredible is the upward trend behavior of the curve in Figure 5, showing significant increases in domestic salt import spending. Figure 5

Multi-Stage Flash (MSF) desalination plants have larger capacity than other plants, such as Reverse Osmosis or electrodialysis (Ibrahim, 1987), and a reject brine concentrate that is twice that of input seawater. Given these considerations it would be highly beneficial for desalination plants in Qatar to incorporate a sodium chloride recovery process into their MSF plants. This in turn would enable Qatar to operate dual-purpose desalination plants. Since desalinated water accounts for about “three-quarters of the total water demand” in Qatar (Danoun, 2007), dual-purpose or “mineral recovery plants” would cut the energy demand cost of single-purpose plants below that of dual-purpose plants. In short, Qatar could completely replace their salt imports with a self-sufficient, salt-producing industry. Brine capacity estimates for Qatar have been calculated in the database belonging to the International Desalination Association (IDA), World Congress. The brine discharge study by IDA concerned brine discharge into the Arabian Gulf from desalination plants along the Arabian coastline, which started from Kuwait to United Arab Emirates. Furthermore, the vast coastline was divided into three groups: A, B, and C. Qatar belonged to Group C, which produced an

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estimated brine reject of 10 million m3/day and in year 2050 it will have increased to approximately 26 million m3/day (Bashitialshaaer and Persson, 2011).

5. Discussion and conclusion

As expected, both RO and IS MED show a significant reduction in the fossil fuel requirement when compared to the BAU MSF plant. However, under the described set of assumptions, RO appears to be a better alternative in terms of LCOE and LCOW than ISCC MED, due to the significantly higher upfront costs of the solar array. Two factors can alter (increase) the future competitiveness of the solar option:

● Economies of scale - according to the literature, CSP plants are feasible above 50MW, which was the size considered for this study. An increased CSP scale could have a positive (decrease) effect on the levelized costs of electricity and water. However, it is necessary to model such scenario in order to make proper conclusions on the effects of solar array scale.

● Further development of the technology can decrease the cost of the panels or increase their efficiency significantly.

For brine waste management, we recommend integrating mineral (sodium chloride) recovery methods into the desalination process. The end salt product could then be sold in both international and domestic markets as a commercial product. Also, since Qatar imports over $24.5 million (usd) of salt each year since 2010 (World Bank, 2010), then salt production from brine waste could turn the $24.5 million (usd) import cost into a surplus. Lastly, operation of dual-purpose desalination plants would cut the energy demand cost of single-purpose plants below that of dual-purpose plants.

Due to huge amounts of reject brine from Qatar desalination plants, in the order of 10 million m3/day, the recovery of salt (Sodium Chloride) becomes feasible. Implementation of our recommendation for producing commercial salt from brine waste in Qatar will create jobs and diversify the business sector, supplement salt import costs of $24.5 million (usd), and operate self-sufficient desalination plants. Work Contributions Magdalena Brum: Anthony Palavi: Brine Waste, EIA, Problem statement & Recommendations (for brine)

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Tyler Lee: Rebecca Quinte:

References Al-Karaghouli, A., and Kazmerski, L.L. (2013). Economic and Technical Analysis of a Reverse-Osmosis Water Desalination Plant using DEEP-3.2 Software, Journal of Environmental Science & Engineering, 1, 318-330. Al-Karaghouli, A., Renne, D., Kazmerski, L.L., Solar and wind opportunities for water desalination in the Arab regions. Renewable and Sustainable Energy Reviews 13 (2009) 2397–2407 Andrea Ghermandi, Rami Messalem, Solar-driven desalination with reverse osmosis: The state of the art, Desalin. Water Treat. 7 (2009) 285–296 Arnal, J.M., Sancho, M., Iborra, I., Gozalvez, J.M., Lora, J., Concentration of brines from RO desalination plants by natural evaporation, Desalination 182 (2005) 435–439 Bashitialshaaer, R., and Persson, K. Desalination Plant and Brine Discharge, Different Arrangements for the Arabian Gulf, International Desalination Association (IDA) World Congress. 2011-09-04 Danoun, R. Desalination Plants: Potential impacts of brine discharge on marine life. The Ocean Technology Group Final, 2007, p. 1 - 59. Darwish, M., Hassabou, A. H., Shomar, B. (2013). Using Seawater Reverse Osmosis (SWRO) desalting system for less environmental impacts in Qatar, Desalination, 309, 113-124. Darwish, M. A., Mohtar, R., Qatar water challenges. Desalination and Water Treatment 51 (2013) 75-86. EIA, Carbon dioxide emission coefficients http://www.eia.gov/environment/emissions/co2_vol_mass.cfm Elimelech, M., and Phillip, W. A. (2011). The Future of Seawater Desalination: Energy, Technology, and the Environment, Science, 333, 712-717.

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Fritzmann, C., Löwenberg, J., Wintgens, T., State-of-the-art of reverse osmosis desalination, ScienceDirect, 2007, p. 1-76. IAEA, Economics of Nuclear Desalination: New Developments and Site Specific Studies.IAEA- TECDOC-1561, 2007. Retrieved from http://www.chem.purdue.edu/gchelp/liquids/vpress.html Ibrahim, S., By-Product Recovery from Saudi Desalination Plants, Elsevier Scence Publishers, Desalination, 1987. p. 97-110.

Index Mundi. (2011). Qatar Imports by Product Sub-Chapter in US Dollars - Salt; sulfur; earths and stone; plastering materials - Yearly. Retrieved from http://www.indexmundi.com/trade/imports/?chapter=25&country=qa Jenkins, S. A and Wasyl, J. (2005). Oceanographic Consideration for Desalination plants in Southern California Coastal Waters. Scripps Institution of Oceanography Technical Report No. 54. Marine Physical Laboratory, University of California, San Diego Kalogirou, S.A., Seawater desalination using renewable energy sources. Progress in Energy and Combustion Science 31 (2005) 242-281. Kämpf, J. and Sadrinasab, M.: The circulation of the Persian Gulf: a numerical study, Ocean Sci., 2, 27-41, doi:10.5194/os-2-27-2006, 2006. Krebs, F. W., Cofer, J. R., & Sieveka, E. H. (1972). Sea-water distillation module. 64(11), 749-760. Retrieved from http://www.jstor.org/stable/41266595 Meier, A., Kornbluth, K., Sabeeh, S., Darwish, M., Complexities of Saving Energy in Qatar. ECEEE Summer Study Proceedings, 1 (2013) 41-48. Okelah, M. R. S., & Tag, I. A. (1992). Performance evaluation of a msf desalination plant in qatar. (Vol. 5, pp. 249-263). United Arab Emirates : Engineering Journal of Qatar University Osman, A. H. (2005). Overview of hybrid desalination systems — current status and future prospects.Desalination 186, 207-214. Probstein, R. F. (1973). Desalination: With fresh water requirements increasing throughout the world, desalinationresearch is proceeding through development of many different promising method.Sigma Xi, The Scientific Research Society, 61(3), 280-293. Retrieved from http://www.jstor.org/stable/27843786 .

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Qiblawey, H.M., Banat, F.,Solar Thermal Desalination Technologies. Desalination 220 (2008) 633–644 Reuther, C. G. (2000). Saline solutions: The quest for fresh water. Environmental Health Perspectives,108(2), 78-80. Retrieved from http://www.jstor.org/stable/3454500 . Shatat, M., Worall, M., Riffat, S. (2013). Opportunities for solar water desalination worldwide: Review, Sustainable Cities and Society, 9, 67-80. Veerapaneni, S. V., Long, B., Freeman, S., & Bond, R. (2007). Reducing energy consumption for seawater desalination. American Water Works Association,99(6), 95-106. Retrieved from http://www.jstor.org/stable/41313322.

World Bank. (2010). Arable Land (% of Land Area) in Qatar. Retrieved from <http://www.tradingeconomics.com/qatar/arable-land-percent-of-land-area-wb-data.html>

Young, K. G. (1971). Desalting technology in pollution-control problems. American Water Works Association, 63(1), 21-24. Retrieved from http://www.jstor.org/stable/41266231 . Appendicies Appendix A: Appendix B: Appendix C: the U.S. Public Health Service considers water to be potable if it has a TDS of less than 500 ppm (Probstein 1973). Appendix D: Brine Waste The World Bank reported that the percentage of Arable Land in Qatar was 1.1% of the total land area (World Bank, 2010). The total land area in Qatar is approximately 11,437 km2 (4,416 sq mi).

Hence: 11,437 x 1.1 = 12,580.7 km2

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