Water Desalination Prestige World Wide November 8, 2011
Outline 1. Fresh Water Situation John Ross Norton 2. History of Desalination Paige Guilbeaux 3. Desalination Process Rachael Solari 4. Economic Feasibility John Ryan Davis 5. Environment and the Future of Desalination Brandon Merril
Fresh Water Situation John Ross Norton November 8, 2011
Global Availability 2/3 of the Earth is covered in water 2.5% is not salty Of that fresh water, 2/3 is contained in ice caps and glaciers 20% of that is in remote areas Much of what s left comes as hurricanes and floods. Only 0.08% of all water is available to humans. [1] Image [2]
US Issues Southwest- Lake Mead has dropped to half capacity. There is a bathtub ring 130 ft above the water s surface along the canyon wall. [3] Midwest- Great lakes are shrinking as communities pull more and more from that resource. Northeast- Upstate New York reservoirs are seeing record lows. [4] Southeast- Atlanta s water need is searching for a cure. Florida and Alabama believe Georgia has already taken more than its share of the Apalachicola-Chattahoochee-Flint river basin. [5]
Texas 3 of top 10 cities facing water shortages are Houston, San Antonio and Fort Worth Lubbock- Meredith Depleted, Alan Henry Ogallala Aquifer heavily depleted Water table has dropped and not being recharged. Image [6]
History of Desalination Paige Guilbeaux November 8, 2011
What is water desalination? Process of removing various salts and minerals from water Used to convert salt water to fresh drinking water http://6ssatnist.files.wordpress.com/2011/04/desalination.jpg
History Water Treatment Through the Years 2000 BC 500 BC 500-1500 Treated for taste Heating, boiling, sand and gravel filtration Bag filter Hippocratic Sleeve Trap sediments Dark Ages Water treatment took a step back
History Water Treatment Through the Years Sir Francis Bacon experimented with sea water desalination Sand Filtration Invention of microscope Water micro organisms first observed Chlorinated water Large sand filters 1627 1676 1890 s
History First Desalination Plants 1950 s http://web.mst.edu/~rogersda/umrcourses/ge342/ http://www.toray.com/news/images/nr071210.gif
The Desalination Process Rachael Solari November 8, 2011
Desalination Process Different Types Multi-stage Flash Distillation Reverse Osmosis Electrodialysis 85% of worldwide production Boiling saline water and collection vapor Most common type of desalination process Semi-permeable membrane traps impurities Removal of salt by separating chemical components More suited for salty groundwater than seawater
Desalination Process Multi-stage Flash Distillation Stage 1 Stage 2 Stage 3 Stage 4 Stage 5 Stage 6 Salt water is pumped through the heat exchangers and warms up Reaches brine heater and adds more heat Sea water is overheated compared to temp. and pressure of initial stage Immediate flash that releases heat and vapor to reach equilibrium Produced vapor is condensed into fresh water on tubular exchanger at each stage Process takes place from hot to last cold stage where fresh water build up is extracted
Desalination Process Multi-stage Flash Distillation http://www.sidem-desalination.com/en/process/msf/
Desalination Process Reverse Osmosis Stage 1 Stage 2 Stage 3 Stage 4 Sea water is pumped in and is mixed with fresh water Enters into the osmosis unit with a semipermeable membrane High pressure is exerted on the high concentration side to overcome the osmotic pressure High concentration solvent is moved through membrane and is now usable.
Desalination Process Reverse Osmosis 1: Sea water inflow, 2: Fresh water flow (40%), 3: Concentrate flow (60%), 4: Sea water flow (60%), 5: Concentrate (drain), A: High pressure pump flow (40%), B: Circulation pump, C: Osmosis unit with membrane, D: Pressure exchanger http://en.wikipedia.org/wiki/reverse_osmosis
Desalination Economics John Ryan Davis November 8, 2011
Is Desalination economically feasible? Dominant Factors Conc. Disposal Facilities & Capacity Financing Location Energy Feed water Labor
Economic Issues with Desalination Technologies costs are falling, but there are still some major issues. Proximity to the ocean Elevation of consuming community Both contribute highly to the cost of transportation Desalination is more costly than other types of water treatment, such as recycled water Possibly only a solution for more prominent communities http://www.libraryindex.com/pages/2644/arid West Where Water Scarce DESALINATION GROWING WATERSUPPLY SOURCE.html
Desalination vs. Traditional Water Sources As the demand increases desalination can become competitive. DESALINATION Cost: $1000 - $4000 / acre-foot Requires large amounts of land, close proximity to coast TRADITIONAL MEANS Cost: $27 - $268 / acre-foot Requires less land, located almost anywhere During times of extreme drought costs of traditional water sources have increased to as much as $2300 / acrefoot.
Desalination in the Middle East Over 12,500 desalination plants worldwide Middle East 60% Saudi Arabia 27 plants, 70% of their drinking water (2005) Israeli Plant: Ashkelon Sea Water Reverse Osmosis Plant -Provides drinking water for 1.4 million people -Produces 108 million cubic meters per year -Approximately 6% of the countries needed drinking water http://www.ejpress.org/article/4873
Environment & the Future of Desalination Brandon Merrill November 8, 2011
Why is Desalination needed? World population will increase by 2.5 billion in next 45 years Desalination water supply expected to triple between 2008 and 2020 Countries with low rainfall totals have a high need for desalination because they cannot rely on groundwater Australia Many African countries
Environmental Concerns Effect on the Ecosystem Draining natural resources Killing microbial and larvae type organisms in the process Disposal of salt deposits and concentrate after the processiscompleted Enormous amounts of energy and pollution expelled in the process Wastewater management
Future Techniques & Improvements Forward Osmosis Evaporation and Condensation Low-Temperature Thermal Desalination (LTTD) Thermo-Ionic Desalination Higher Efficiency Plants Solar Desalination Plants More Efficient Membranes Nanotubes Biomimetic
Conclusion Increasing water conservation and water use efficiency is the most costeffective means for increasing the amount of available water If plants and disposal processes can be improved, it makes desalination a viable option The increase in population will undoubtedly lead to an increased water shortage. The need for desalination improvements is undeniable.
Questions? Prestige World Wide November 8, 2011
References [1] http://news.bbc.co.uk/2/hi/science/nature/755497.stm [2] http://www.worldwatercouncil.org/index.php?id=25 [3] http://www.cbsnews.com/stories/2010/01/08/eveningnews/main6073416.shtml [4] http://www.naturalnews.com/022915.html [5] http://chronicle.augusta.com/news/government/elections/2010-05-18/new-governor-will-inheritgeorgias-water-crisis?v=1274226159 [6] http://en.wikipedia.org/wiki/ogallala_aquifer [7] http://en.wikipedia.org/wiki/desalination [8] http://www.lenntech.com/history-water-treatment.htm [9] http://www.goldcoast.qld.gov.au/attachment/goldcoastwater/ebws_fs4.pdf [10] http://en.wikipedia.org/wiki/desalination [11] http://www.ejpress.org/article/4873 [12] http://www.libraryindex.com/pages/2644/arid West Where Water Scarce DESALINATION GROWING WATERSUPPLY SOURCE.html