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CT: Renewable Energy Desalination: An Emerging Solution to Close MENA’s Water Gap.
Many countries in the Middle East and North Africa (MENA) region are facing real water security challenges. In arid, coastal cities, water demand is often met through large-scale desalination systems powered by fossil fuels. While groundwater and surface water resources are dwindling due to population growth and climate change, more desalination plants will be required to meet the water demand gap.
With rising fuel prices, however, many countries will need to look to renewable energy sources, like solar and wind, as an alternative source for water provision. Desalination can, therefore, present an opportunity for developing countries to meet their water supply needs while at the same time developing their renewable energy potential.
To support research on potential projects in this area, the WPP co-funded an extensive study entitled “MENA Regional Water Outlook: Desalination Using Renewable Energy”. The study assesses water availability and demand projections, as well as implications of climate change impacts on water in the Middle East and North Africa Region (MENA) up to 2050. Covering 21 countries, the report includes various technology scenarios for desalination plants using renewable energy. The assessment focuses on the use of Concentrated Solar Power (CSP) as a reliable energy source for the region. By presenting information on the generation potential and associated costs of desalination, the study is the first step in helping countries determine whether to promote such strategies in the long-term.
S: http://water.worldbank.org/node/84110 (last access: 4 December 2015)
N: 1. Word composed by the active word-forming element in English and in many words inherited from French and Latin de-, which means ‘down, down from, from, off; concerning’ and the word ‘salination’.
Salination is formed by the adjective ‘saline’ that comes from Latin sal (genitive salis) ‘salt’, ‘made of salt’, and the word-forming element attached to verbs ‘-ation’, making nouns of state, condition, or action, from French -ion or directly from Latin -ionem (nominative -io, genitive -ionis). As a verb, ‘desalt’ is recorded from 1909.
2. Desalting is actually a natural, continual process and an essential part of the water cycle. Rainwater falls to the ground and eventually flows to the sea, moving over and through the earth, dissolving minerals and other materials along the way, and becoming increasingly salty. As water evaporates through the sun’s energy, it leaves the salts behind, and the resulting water vapor forms clouds that produce rain, thus continuing the cycle. People have been desalinating water for centuries. One of the first mentions was by Aristotle, who wrote of seawater distillation in 320 BC.
3. Today, developments in desalination technologies are specifically aimed at reducing energy consumption and cost, as well as minimizing environmental impacts. Advancements include such new and emerging technologies as forward osmosis, low temperature distillation, membrane distillation, pressure retarded osmosis, biomimetic and graphene membranes. Hybrid plants (especially those using MED) and reverse osmosis are gaining wider use in the Middle East, which has traditionally been home to facilities using more energy-intensive thermal technologies such as MSF.
4. The desalination industry is also paying a great deal of attention to environmental considerations. Environmental safeguards have become increasingly important in siting and permitting of new plants. Monitoring programs are being more widely utilized. Lower energy consumption reduces also a plant’s carbon footprint, and in addition, new technologies are being used successfully to lessen disruptions to marine life during the intake and outfall processes. Studies such as IDA’s Blue Paper on Desalination and the Gulf have raised awareness of steps to leverage best practices and mitigate potential environmental effects of desalination.
5. The desalination core process is based on Reverse Osmosis Membrane technology, but stand alone, it doesn’t provide safe drinking water, nor does it guarantee an efficient plant.
- The pretreatment includes all the necessary treatment step ahead of the reverse osmosis plant. It is determining for plant life time and to minimise chemical cleaning and membrane replacement. It has a direct impact on the plant performance.
There are as many membrane types as applications. They range from “high rejection” to “ultra low energy” or ” high boron rejection”.
The reverse osmosis process can also be built with one or two passes, depending on the product water requirements and the seawater salinity and temperature. In most cases, 1 pass is sufficient to reach the EU drinking water standards, specially regarding the boron content (1 mg/L). To reach WHO boron guideline (0.5mg/L), a second pass might be necessary (Boron removal process)
The energy recovery device is the key factor that determines the plant electrical costs. It must be chosen carefully based on the local energy costs and environment policies.
- Post-treatment and/or polishing steps are required to condition the water after the reverse osmosis membrane process to make it suitable to your application.
Brine disposal can be an environmental and economical issue in some areas where the fauna and flora are sensitive to local seawater salinity increase. Brine disposal should be studied and engineered case by case.
The art of desalination is to determine and combine available technologies to optimize water production costs and quality.
To adapt our Desalination Plants to your local needs, we offer containerized mobile units from Intake to Distribution up to a production capacity of 200 m3/h of desalinated water.
6. A desalination plant essentially separates saline water into two streams: one with a low concentration of dissolved salts (the fresh water stream) and the other containing the remaining dissolved salts (the concentrate or brine stream). The plant requires energy to operate and can use a number of different technologies for the separation of the saline water. The amount of the feed water discharged to waste in the brine stream varies from 20 to 70 percent of the feed flow, depending on the technology employed and the salt content of the feed water.
Desalination is becoming more economically viable as the technology improves. Desalination plants can be provided in a wide range of outputs to cater for small isolated communities or to contribute substantially to water supplies for large cities and even for irrigation (Spain, United Arab Emirates).
7. Desalination is often misspelled: desaltation, desalinization, desalinisation, desalisation, desalization or Desal Plant.
S: OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=Desalination&searchmode=none (last access: 29 November 2015). 2. IDA – http://idadesal.org/desalination-101/desalination-overview/ (last access: 1 December 2015). 3. IDA – http://idadesal.org/desalination-101/desalination-overview/ (last access: 29 November 2015). 4 & 5. LENNTECH – http://www.lenntech.com/processes/desalination/general/desalination-key-issue.htm (last access: 1 December 2015). 6. AUGOV – https://goo.gl/EzU5WY (last access: 1 December 2015). 7. LENNTECH – http://www.lenntech.com/processes/desalination/general/desalination-key-issue.htm (last access: 4 December 2015).
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