Assessing the Feasibility of Different Techniques for Providing Fresh Water to Arid Regions of the World - Term Paper Example

Running head: ASSESSING THE FEASIBILITY OF DIFFERENT TECHNIQUES FOR PROVIDING FRESH WATER TO ARID REGIONS OF THE WORLD Assessing the Feasibility ofDifferent Techniques for Providing Fresh Water to Arid Regions of the World Insert Name Insert Grade Course Insert Tutor’s Name 01 December 2010 Assessing the feasibility of different techniques for providing fresh water to arid regions of the world Introduction As the population swells and the cost of living escalate, fresh water inadequacies in certain parts of the world are increasingly becoming heightened. Those areas that are specifically affected include the Middle East, North Africa, parts of Australia and the Pacific Southwest United States (Hult and Ostrander, 1973, p. 5). In a number of these arid areas, water may be accessible by obtaining it from river basins that have plenty of water or by the process of desalting seawater. Other nations employ the use of rainwater harvesting and water recycling. However, the costs of carrying out such processes tend to restrict their use. Use of desalination process is applicable in most parts of the world with its feasibility being based on aspects energy and eco-friendliness. On the other hand, rainwater harvesting is suitable in those areas that are agriculture oriented and their rainfall distribution can allow for runoffs. Most parts of the Middle East meet its viability. The feasibility of Desalination Desalination is the process of eliminating that solid material that has dissolved in water especially salts and other lifeless variety. Desalination takes place in the normal natural setting as water evaporates from the seas, lakes, and oceans to move upwards, precipitate, and form clouds. Historical descriptions and records, including the setting of some of the earliest Greek philosophers reveal that humanity has been using desalination since long ago to come up with drinking water. The arid situation in some parts of the world has contributed towards the increased use of desalination to create fresh water that can enable them carry out various purposes with it. Studies reveal that desalination technology is used in about 125 countries globally, with the United States leading in its application (National Research Council, 2004, p.12). Several desalination know how are used in different parts of the world to remove salt from seawater. The type of technology used is dependent on some factors such as quality of the water source, anticipated purpose for the water being desalinated, size of the plant, capital, and energy charges and the possibility of energy reuse. In desalination process, thermal technologies are used to heat seawater, which then evaporates forming vapor. The vapor is then condensed to become fresh water. The use of thermal technologies was common many decades ago. From 1950, there was a shift from thermal use to use of membranes to desalinate brackish water (Escobar and Schafer, 2009, p. 10). The Middle East is among the main users of desalination with most of their plants producing up to a capacity of 1.6Mm3 daily (Escobar and Schafer, 2009, p.14). Global seawater desalination is prevalent in the Middle East, Southern Europe, and North Africa at 61%, 11%, and 7% of the global seawater desalination capacity respectively. The costs for production of water have escalated depending on the nation, supply, need for the water and know how. Concurrently, the cost of drinking water from desalination has been declining, in some cases even lower than the cost of traditional water production. The factors that encourage this are better design and technology particularly that of Reverse Osmosis process, the application of facilities to domestic demand, or the use of inexpensive energy sources. The average investment cost for ensuring that a desalination plant has been erected and is operational is lower. The estimated costs of production, which includes spare parts and membranes, chemicals required for plant cleaning and treatment, labor costs, and energy demand lie within the range US$ 0.45-0.60 / m3. With the latest rise in energy prices, desalination may become an exorbitant water supply alternative in the days to come (Escobar and Schafer, 2009, p.15). The energy demand of the plant is process dependent. Most of the processes involved like seawater Reverse Osmosis, and distillation make use of low amounts of energy as shown in figure 1 below. The amount of energy used is also determined by equipment used and for this, using energy membranes that require low energy, non-fixed frequency pumps and pressure exchangers reduce the amount of energy needed for the operation of the plant. Generally, the feasibility of the desalination process is based on the affordability of the equipment and processes used the amount of energy costs and the eco-friendliness of the process. Although evaporation and distillation processes of desalination use high energy amounts and enhances carbon emissions, the freeze distillation and reverses osmosis processes are both economically and environmentally viable (Gray, 2008, p. 109). Figure 1: Sustainable Water for the Future: Water Recycling Versus Desalination (p. 15) Table 1: Sustainable Water for the Future: Water Recycling Versus Desalination (p. 16) Water Harvesting The problem of water shortage in most of the global arid regions has compelled most countries to resort to most conventional technologies of managing water. Top among them is water harvesting. Rainwater harvesting can be broadly explained to be the process of inducing, gathering, keeping and preserving domestic surface run off for agriculture in dry areas (Prinz and Singh, 2000, p. 2). In addition, rainwater harvesting may be for domestic use and environmental management. A rainwater harvesting system has three main components: Catchment or roof surface for collecting water, delivery system to aid in water transportation from the roof to the storage area, and the storage reservoir to keep the water up to when it will be used. Catchment Surface This refers to that face upon which water flows from the rainfall directly as it is drained into the system. Due to compromise on quality, water from the surface is not normally suitable for consumption. Any other roofing can be used in collection of water except thatched, lead and asphalt covered roofs. Roofs suitable for this purpose are either galvanized or corrugated iron or plastic sheets. Flat cement and undamaged asbestos may be used. Delivery Structure The system of delivery from the rooftop normally comprises of gutters dangling from the sides of the roof and directed towards a tank via a pipe. The delivery structure functions at transporting water from the roof to the reservoir. In effective rainwater harvesting, the guttering is normally the most essential aspect and it is the weakest link in the entire system. It should therefore be properly designed and made. Gutters are mainly made from metal and PVC. Storage Tanks This normally takes the largest capital investment in the rainwater harvesting exercise. Huge volumes of water are stored in tanks that are situated either above or below the ground. Generally, round shaped reservoirs are stronger and comprise of less material than the flat shaped ones. Frequent maintenance and sanitation of the reservoir are paramount to avert contamination of stored water (Hattum and Warm, 2006, p. 17). Parameters for the Feasibility of Rainwater Harvesting Rainfall The intensity and distribution of rainfall determines the setting up of a rainfall harvesting system within a given region. The rainfall intensity determines the kind of rainfall that can provide runoff. Certain rainfall aspects that are used to determine the construction of a rain harvesting system include the during in days when the rainfall amount is more than the threshold level, the annual probability and incidences of mean monthly rainfall, the possibility and recurrence of the monthly rainfall at the lowest and highest possible levels, and the regular spread of different storms (Prinz and Singh, 2000, p.4). Vegetation Cover Studies show that an increase in vegetation density results to an increase in retention and permeation rates, which in turn leads to a reduction in the runoff volume. There is also a strong relationship between the vegetation cover and the fitness of the soil to apply in cropping. Socio-economic and infrastructure factors: The community’s farming methods, the fiscal ability of the average farmer, the cultural belief, the religious tendencies of the people, the flexibility of the local farmers regarding adoption of new farming methods, their information regarding irrigation-supported agriculture, period of land ownership, role of women and other minor groups in the society play an important role in designing a rainwater system within a given region (Prinz and Singh, 2000, p.5). For example, in Egypt, where water shortage is rampant, the government has established a financial institution that can enable farmers to access fiscal aid that can be used in water management (Oxford Business group, 2010, p.198). Water harvesting has been used in the Middle East, China, North Africa, North America, and India mainly for crop production. The conditions in these regions necessitate its use due to a timely plausible distribution of rain (Woyessa et al, 2006, p.2). References Escobar, I. C. and Schafer, A. (2009). Sustainable Water for the Future: Water Recycling Versus Desalination. Oxford: Elsevier. Gray, N. F. (2008). Drinking Water Quality: Problems and Solutions. New York: Cambridge University Press. Hattum, T. and Worm, J. (2006). Rainwater Harvesting for Domestic Use. Netherlands: Agromisa Foundation. Hult, J. and Ostrander, N. (1973). Antarctic Icebergs as a Global Fresh water resource. Retrieved from http://www.rand.org/pubs/reports/2008/R1255.pdf. National Research Council. (2004). Review of the desalination and water purification technology roadmap. Washington D.C: National Academic Press. Oxford Business group. (2010). The Report: Egypt 2010. New York: Oxford Business Group. Prinz, D., and Singh, A. (2000). Technological potential for Improvement of Water Harvesting. Retrieved from http://docs.google.com/viewer?a=v&q=cache:Nd4BrgxmNXYJ:citeseerx.ist.psu.edu/viewdoc/download%3Fdoi%3D10.1.1.168.4275%26rep%3Drep1%26type%3Dpdf+Technological+potential+for+Improvement+of+Water+Harvesting.&hl=en&pid=bl&srcid=ADGEESgGuqBMRFenMeoDymQnnYCa670sLsEJb-IWh2qAghp_q4LbkAlHELiHEzQgSD0hOhnf_N_rN4fOV9npiY3dZI_DXUM-RIikrB4LDb3qQxpnyI2lcjdRiKHvdQ5gN6C4yeWoHaNd&sig=AHIEtbSF7QoyNBe7mX8NAbcKlyBpAbmukg. Woyessa, Y. et al. (2006). Informal Irrigation in Urban West Africa: An Overview. Cape Town: Comprehensive Assessment secretariat. Read More