The Recipe for Freshwater - Assignment Example

Article review (Name) (Institution) (Course) (Instructor’s Name) Date of submission The article “Add salt as required: the recipe for fresh water” by Kate Ravilious published in the New Scientist Magazine issue number 2773 on 11 August 2010 discusses the construction of a desalination plant in Melbourne and discusses technologic progress in the desalination process. The writer highlights the construction of a canal to feed a desalination plant with seawater as the world turns to the salty sea water for drinking and other domestic chores. Fresh water has never been a rare product like it is now. Fresh water bodies such as dams, lakes and rivers that have conventionally provided fresh water have nearly dried up after several years of drought in the continent. In spite of this, demand for fresh water has not declined but instead gone up creating a shortage. In response, the government has sought to clear this shortage by sourcing water from the sea and purifying it for domestic use, a process called desalination. First of all one should question why there is a water shortage that has necessitated desalination. The author ignores this and assumes that her audience is already aware of the existing climatic conditions which lead one to conclude that the article primarily targets Australians. A look into a number of sources indicate that one of the greatest consequences of man’s activities earth’s surface is global warming which is manifested by unpredictable climatic patterns drought being a common one (Pigram 2006). Global warming is caused by pollution and misuse of the natural environment in the process of economic development. However, economic development cannot be substituted for environmental degradation and hence there must be a sure way of ensuring that as man and governments develop, the environment is protected. Economic growth must be sustainable. In fact, every element of development whether corporate, national, interstate or personal, must be made sustainable i.e. to be self-supporting in the long run. So is drought a necessary requisite for desalination? The article seems to allege this though other authors defer. Kalogirou (2005) says that desalination is a product of need and not necessary environmental destruction or drought. He notes that desalination dates back to 4BC where sailors boiled seawater during their voyages to obtain fresh water. This contrasts the approach taken by Ravilious who presents desalination as a solution to the problem of drought brought about by environmental degradation. This article contains subheadings and a number of recall boxes that highlight the major points of the article. It takes different perspectives in discussing desalination. First and foremost it approaches desalination as a positive response by the government to address the problem of water shortage in Melbourne and Australia at large (Ludwig, Kabat and Schaik 2009). The idea of turning seawater into clean fresh water excites any Australian who has been exposed to the recent water shortage triggered by prolonged droughts. Although many other countries are involved in desalination, not all of them are faced with drought such as the UK. However, others more in the Middle East have traditionally relied on desalination to serve their water needs. Ravilious feels that the UK is rain drenched yet it has taken up to desalination. Does this imply that desalination is a cheaper source of fresh water than other sources? (Escobar & Schafer 2010). The writer answers this rhetorical question by highlighting the energy demands of desalination. She notes that despite the fact reversed osmosis as the preferred desalination process requires less energy compared to other processes, its energy needs are way too high to be sustainable. The new plant in Melbourne is expected to consume around 90 megawatts of electrical power to produce 150 billion litres annually. This is one of the major drawbacks of desalination; such revelations warn the public against celebrating yet. The article takes an informative dimension to educate the audience about the technologic developments in desalination. The author indicates that there have been recent breakthroughs in reducing the amount of energy needed for reversed osmosis. However, the major problem is that such newer technologies have only been tried in small scale. One of the American companies leading in innovation in this direction is Hydration Technology Innovations which developed a product named X-pack that allows a person to obtain clean drinking water from muddy or salty water. The product is already in the market. However, its reliability is limited because it is expensive to produce. Development is this direction is also limited by the high cost of developing a membrane that allows water and not salts to filter through. This explains to the public why such items are needed in disaster prone areas. The author fails to explain other technologies used in desalination. Einav, Harussi and Perry (2002) discuss various techniques of desalination to help the audience better understand the differences in energy demands and technicalities which Ravilious fails to explain well. The authors discuss reverse osmosis, electrodialysis, multi stage flash, multi effect distillation and vapour compression. They confirm what Rivilious says that RO is the most common method. It involves separation of two liquid concentrations by a semi permeable membrane. Under the normal osmosis process, water would flow from the side of low chemical concentration to that side of higher chemical concentration given that the chemicals in this case cannot move past the membrane. However, reverse osmosis acts differently as it forces water to flow from the side of higher chemical concentration to that of lower chemical concentration. By being informative, Ravilious should have explained the other processes in brief in order for the audience to weigh the pros and cons of each process. Nonetheless Einav, Harussi and Perry (2002) discuss an alternative process; electrodialysis which is suitable in places far away from the oceans but nearer mines and wells as it best cleanses brackish water. It involves using a number of membranes and two electrodes. However, this process is more energy intensive than RO. The other three processes, Multi effect distillation, Multi stage flash and Vapor compression distillation rely on evaporation of water aided by electric power. Ravilious titles her paper in such a manner to suggest that salty water is healthy. She also places an opening statement that elicits thoughts that a cheaper and more energy efficient desalination process has been discovered. Although she indicates that there has encouraging innovations, the world is still very far from accessing sea water in the same way as it would rainwater. Although she does recognise the energy demands of desalination and the fact that the X-pack cannot be used in large scale, she still portrays the establishment of the Melbourne desalination plant as a breakthrough where “we're learning to go with the flow” which is misplaced. Alternatively, the author is wrong to indicate that the world is learning how to go with the flow because she does not indicate how the world or Australia to be specific has learnt how to avoid desalination in the first place. One thing that the writer implies by describing the canal that will draw water from the ocean to the desalination plant is the destruction of the natural beauty of the Australian beaches. She says that the canal will measure 4 metre wide, 1.5-kilometre-long and 27-metre-deep. Unfortunately, describing such measurements does not have the same impact that a photograph of the canal to accompany the article would have had. This marks one disadvantage of desalination. Other scientists have also been quick to discredit desalination as a viable alternative to sourcing fresh water something that Ravilious does not address full heartedly. In many of the articles that discuss desalination, they do so with an inclusion of the dangers of desalination. Einav, Harussi and Perry point out that desalination has become a necessity even on the environment which seemingly solves short term problem but does not solve the problem of water shortage in the long term. They note that excessive exploitation of ground water and poor harvesting of rain water has not helped in easing the demand for fresh water. As a result, societies are being forced to turn to sea water. In this regard, the article should have addressed the issue of environmental degradation which has led to erratic climatic conditions and drought. In this age of sustainability, where does desalination stand in the face of environmental conservation? Einav, Harussi and Perry (2002) cite five major impacts of desalination to the natural environment. As aforementioned desalination plants are constructed long shorelines taking spaces that could be alternatively used for recreation and tourism. Australia for instance boasts of beautiful beaches which are threatened by such developments. Efforts to locate such facilities away from the shoreline would also create problems in terms of added costs on transporting sea water and also the risk posed by sea water in case of leakage to the ground. This places a direct threat to the aquifer and as a country that also relies on ground water, this idea would complicate the problem. The natural environment of the Australia as a continent predisposes it lower fresh water availability as compared to other continents. Ravilious ignores this aspect completely while other authors have been vibrant in indicating the causes of water shortages in Australia that have resulted into exploration of desalination. Wahlquist (2008) says that Australia experiences higher evaporation rates that rainfall which is as ten times higher than rain in some areas. This implies that the country is constantly at deficit when it comes to water. Another interesting fact that Ravilious fails to mention in his paper is that desalination is not exclusive to sea water only. The fact that Australia enjoys almost conventional rainfall entirely implies that the rain has some relatively higher amounts of salts. Given that the country is relatively flat, water evaporates quickly as it flows down slowly across the surface leaving behind salts. The salts eventually find their water to underground water reservoir. This implies that some underground water maybe very salty such that it requires desalination. In fact Pigram (2006) writes that majority of desalination plants in Australia are located in inland mining towns and specialise in processing brackish water and salty underground water. Ravilious’ article is informative and meant for the general public. In writing the paper he makes no assumption that the reader has no prior knowledge about desalination and thus introduces the topic and develops his discussion progressively. References Einav, R., Harussi, K. & Perry, D. (2002). “The footprint of the desalination processes on the environment.” Desalination 152 (1), 141–154 Escobar, I. & Schafer, A. (2010). Sustainable Water for the Future: Water Recycling Versus Desalination. London: Elsevier Kalogirou, A. (2005). “Seawater desalination using renewable energy sources.” Progress in Energy and Combustion Science 31 (1) 242–281 Ludwig, F., Kabat, P. & Schaik, H. (2009). Climate change adaptation in the water sector. Sydney: Earthscan Pigram, P.(2006). Australia's water resources: from use to management. Sydney: Csiro Publishing Ravilious, K. (2010). “Add salt as required: the recipe for fresh water.” New Scientist Magazine. 2773. Accessed online on 20/08/2010 from http://www.newscientist.com/article/mg20727731.400-add-salt-as-required-the-recipe-for-fresh-water.html?full=true Wahlquist, A. (2008). Thirsty Country: Options for Australia. Melbourne: Allen & Unwin  Western Australia Water Corporation (2006). 'Desalinisation' paper prepared for the 2006 Australian State of the Environment Committee, Department of the Environment and Heritage, Canberra, Accessed online on 20/08/2010 from http://www.environment.gov.au/soe/2006/publications/emerging/desal/index.html Read More