Desalination

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Desalination

  1. 1. DESALINATION IN CYPRUS Comenius programme, Paterna - Spain, May 2009 Presentation by the students of St George’s Lyceum Larnaca participating in the project.
  2. 2. CONDITIONS IN CYPRUS <ul><li>Available water depends on rainfall </li></ul><ul><li>Rainfall only takes place in winter </li></ul><ul><li>Rainfall is geographically unequally distributed </li></ul><ul><li>Changes in rainfall through the years, with repeated droughts </li></ul>
  3. 3. CLIMATE CHANGE AND DROUGHTS <ul><li>From 1970’ s and onward rainfall is getting less and less. The mean average of rainfall in the 1990/2000 decade was 15% less than the rainfall of the 1960/1990 period </li></ul><ul><li>Droughts are more often as the years go by </li></ul><ul><li>The 1990/2000 decade, had 7 years of drought </li></ul>
  4. 4. YEARLY RAINFALL IN CYPRUS AND MEAN AVERAGE 1901-70 VS. 1971-2005
  5. 5. RESULTS DUE TO THE SHORTAGE OF WATER <ul><li>Cuts up to 30% of the normal demand to the domestic sector </li></ul><ul><li>Cuts up to 70% of the normal demand to the agricultural sector </li></ul><ul><li>Different kinds of problems arise: environmental, social, economical </li></ul><ul><li>-> due to the problems arising from decreased water availability, the government of Cyprus decided to construct desalination plants </li></ul>
  6. 6. DESALINATION PLANTS IN CYPRUS DHEKELIA LARNACA Starting date April 1997 July 2001 Productivity 40 000 m 3 /day 52 000 m3 /day Minimum daily 36 000 m 3 46 500m3 Trimester - minimum 3.2 85 .000 m ³ 4 .2 43 . 125 m ³ Year - minimum 13.140.000 m ³ 16.972.500 m ³ <ul><li>Additionally, there are plans for: </li></ul><ul><li>expansion of the two units (already taking place) </li></ul><ul><li>building three new seawater desalination facilities by 2013 </li></ul><ul><li>(in Limassol and Paphos areas) </li></ul>
  7. 7. DESALINATION PLANT COMPONENTS <ul><li>Intake and outfall underwater pipelines </li></ul><ul><li>Seawater pumping station </li></ul><ul><li>Intake and outfall land pipelines </li></ul><ul><li>Desalination plant </li></ul><ul><li>Pre-treatment phase </li></ul><ul><li>Reverse osmosis phase </li></ul><ul><li>Post-treatment phase </li></ul><ul><li>Pipelines for delivering fresh water </li></ul>
  8. 8. DESALINATION PROCESS STAGES
  9. 9. Stage 1: Sea Water Intake <ul><li>Intake pipe </li></ul><ul><li>Screens </li></ul><ul><li>Pumping Station </li></ul>
  10. 10. Stage 2: Pre - Treatment <ul><li>Coagulation /flocculation </li></ul><ul><li>Dual media filtration </li></ul><ul><li>Booster pump </li></ul><ul><li>Micro filtration </li></ul>
  11. 11. Stage 3: Reverse Osmosis <ul><li>High pressure pumps </li></ul><ul><li>Membrane trains </li></ul><ul><li>(1st & 2nd stage) </li></ul><ul><li>Energy recovery </li></ul><ul><li>Antiscalant dosing </li></ul>
  12. 12. Stage 4: Post - Treatment <ul><li>Chemical dosing </li></ul><ul><li>Limestone reactors </li></ul>
  13. 13. Stage 5: Storage and Distribution <ul><li>Product tank </li></ul><ul><li>Chlorination </li></ul><ul><li>Pumping station (13 km) </li></ul>
  14. 14. IMPORTANCE OF THE DESALINATION PLANTS <ul><li>The two plants (Larnaca and Dekelia) supply water to the Nicosia –Larnaca – Famagusta water supply system with a nominal daily supply of 92 000 m 3 which represents 90% of the demand of these regions </li></ul><ul><li>Larnaca, Famagusta and Nicosia do not mainly depend on rainfall </li></ul><ul><li>Needs of Limassol and Paphos are supposed to be met by the two new units that are planned to be built </li></ul>
  15. 15. ENVIRONMENTAL ISSUES <ul><li>Big demands in power supply </li></ul><ul><li>Atmospheric pollution due to increased gas emissions for the production of the extra energy </li></ul><ul><li>Minor effect to the marine environment in which the brine is discharged (brine contains seawater salts with concentrations almost double than that of seawater plus some chemicals). The results so far obtained (from monitoring) show that the effects are negligible and they are limited to an area with radius of 200 metres around the point of discharge – rearrangements of the benthos life </li></ul><ul><li>Noise pollution </li></ul>
  16. 16. CONCLUSIONS <ul><li>The unavoidable construction of desalination plants proved very beneficial for both domestic consumption and agriculture </li></ul><ul><li>Desalination should not be considered a panacea: </li></ul><ul><li>- Environmental cost (mainly air pollution) should be taken into consideration especially after the climate changes happening in our planet and affecting our ecosystem </li></ul><ul><li>- Economic dimensions. Desalinated water is more expensive than conventional water and it consumes large quantities of energy which is imported in Cyprus. </li></ul>
  17. 17. <ul><li>Thank you for your attention </li></ul>

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