Water+Desalination+-+M.+Morris

=__ Water Desalination __= by Mike Morris

The problem at hand is that with global climate change now and in the near term future there probably will be fresh water shortages in populated areas in many places throughout the world. In order to avoid humanitarian crises and possible conflicts it is important for humans to finds ways to develop alternative forms of fresh water production in order to meet human demand.
 * What is the problem at hand**?

As mentioned previously the driving force behind fresh water shortages is climate change. Scientists believe that global climate change is being caused by carbon dioxide production from the burning of fossil fuels.
 * What is the driving force of the problem**?


 * What are people currently doing or not doing to solve the problem**?

People are investing in renewable energy technology and in machines that are more energy efficient in order to reduce our dependence on fossil fuels. Using energy more efficiently and moving to renewable sources of energy (e.g., wind, solar, geothermal and bioenergy) would significantly reduce emissions of heat trapping gases. One area where there is currently a great effort being made to increase fuel efficiency is in automobiles since automobiles burn about 70% of the fossil fuels human's use.

There are two popular processes in water desalination. The first process, is thermal distillation (47% of the desalinization plants), a process whereby salt water is boiled and water vapor is then condensed as potable water. This process is set-up so as to operate on the principal of reducing the vapor pressure of water within the unit to permit boiling to occur at lower temperatures, without the use of additional heat. The vapor pressure in each of these stages is controlled so that the heated salt water enters each chamber at the proper temperature and pressure. Distillation units use designs that conserve as much thermal energy as possible by interchanging the heat of condensation and the heat of vaporization within the units. The major energy requirement in the distillation process is providing the heat for the vaporization to the feed water.
 * Explain how water desalination works.**

The second desalinization process, reverse osmosis (37% of the desalinization plants), is a process where salt is separated from water by forcing the salt water through water permeable membranes (i.e., filters) under pressure. The water is forced through the membranes by the pressure and the salt is caught in the membrane. The water that flows though the membranes is potable water. No heating or phase change takes place. The major energy requirement is for the pressurization of the salt water. Pressures range from 800 to 1000 psi for sea water.


 * Determine the amount of CO2 it produces or inhibits.**

Reverse Osmosis (RO) (1.78kg CO2 per m3 of produced water) and thermal distillation technologies of multistage flash (MSF) (23.41 kg CO2/m3).


 * Determine the amount of water it can generate or purify.**

Today desalinization plants can produce 50 gallons of fresh water for every 100 gallons of sea water they take in. Desalinization plants are energy intensive. The amount of water that can be generated by a desalinization plant is related to the size of the plan and the salt content of the water. Today there are more than 12,500 desalinization plants world wide and 60% of them are located in the Middle East. It is estimated that these plants produce approximately 7 billion gallons of potable water per day.


 * Highlight the best aspects of it.**

The major advantage of desalinization of salt water is that with the oceans, salt water is plentiful. Water desalinization plants produce a superior product today. Water desalinization plants cover less land space than reservoirs. Also, desalinization plants are flexible in that a country or a state can place a desalinization plant practically anywhere it wants.


 * Describe how the critics would discuss it.**

Critics of desalinization plants are concerned about the high energy cost related to the desalinization process (energy costs can run anywhere from 30 to 60% of the total desalinization costs) and the disposal of the salt concentrate. Another concern related to desalinization plants is how to ship the fresh water produced to areas that need the water. Currently it’s not economical to pipe this water far inland or up to mountainous areas.


 * If it already makes up a lot of the world's fuel/energy supply explain why.**

Desalinization makes sense for a couple of reasons. First, only 2% of the world’s drinking water is fresh, and that percentage isn’t growing while the world’s human population is. Second the cost of operating desalinization plants is coming down.


 * If it doesn't make up much of the world's fuel/energy supply explain why.**

Desalinization plants don’t currently make up a great percentage ( currently only 1% of the world’s fresh water use is produced by desalinization) of the world’s fresh water. However, considering 25% of the world’s population lives within 16 miles of the coast, desalinization could become a significant source of fresh water for humans in the future.


 * Explain how it could help solve some of the problems or contributes to those problems.**

In the future desalinization could help bring fresh water to areas of the world stricken by water shortages and drought. The technology is becoming more energy efficient and is flexible enough that is can be set-up almost anywhere. With a static global fresh water supply, a growing human population and the unpredictability of what climate change means, desalinization offers a useful way of providing more fresh water in the near term future.


 * Explain what it would take to do your thing better or in a larger scale**.

There are two things that would cause the use of desalinization plants to grow rapidly. The first would be world-wide water shortages. Obviously is the current supply of fresh water were to be reduce in some way, the need to produce fresh water through desalinization would increase. The second thing that would cause the growth of desalinization plants is if there is a dramatic decrease in the cost of desalinization.


 * Explain who uses that technology and why. If it isn't used very much explain that instead.**

Middle East nations are the heaviest users of desalinization technology right now because many of the Middle Eastern countries are arid countries. Spain in Europe is a major market for desalinization plants and California in the U.S. currently has several proposals for desalinization plants under consideration right now.


 * After learning about it what would you do next to change how its used? why?**

I would investigate possibilities for the construction of cogeneration plants (electricity plant that produces heat and electricity). Cogeneration plants are facilities where the heat energy given off by the main plant can be used to produce water through desalinization plants. I would also investigate the use of nuclear powered desalinization plants because they have the potential to produce large amounts of fresh water.


 * Quotes:**

//If we could ever competitively, at a cheap rate, get fresh water from salt water, that it would be in the long-range interests of humanity which would really dwarf any other scientific accomplishments."// //--//John F. Kennedy, 1962

//“[We need] a farsighted program for meeting urgent water needs by converting saltwater to fresh water.”// //--//Dwight D. Eisenhower, 1951 How desalination will help interior states:

//"Larry Dozier, deputy general manager of the Central Arizona Project and one of the people working on the seven-state proposal, said cloud seeding is only a stopgap solution and not one that could cover all (water) shortages in dry years. He wants the states to explore even more innovative ideas, such as building a water desalination plant on the Gulf of California."// --"Colorado River states look for ways to stretch water supply" The Associated Press (December 14, 2005)


 * Pictures:**


 * Water desalination plants of Ross Islands.**


 * Brackish (salty) water desalination plant.**


 * Model of a water desalination plant.**


 * [|Trading carbon credits]**


 * [|Australian carbon credits]**

http://en.wikipedia.org/wiki/Desalination http://www.ucsusa.org/global_warming/solutions/ http://www.newwatersupply.org/news/quotes.htm http://ec.europa.eu/environment/etap/pdfs/watedesalination.pdf http://tinyurl.com/2ecnl7 http://www.solcomhouse.com/globalwarming.htm http://envplan240.pbwiki.com/Desalination http://pls.atu.edu/biology/people/elovely/Water/new_page_1.htm
 * Sources:**