Methods of Water Provision in Arid Areas - Essay Example

METHODS OF WATER PROVISION IN ARID AREAS Arid areas are characterized by low levels of precipitation; in most cases, they record an average of 75mm annual rainfall. However, water is a basic commodity both at household level and for industrial purpose hence, its inadequacy is critical and must be compensated by other means. With the numerous oil resources in arid countries such as the Gulf region, provision of fresh water is made possible through funding of various water purification processes. This paper discusses desalination and Recycled water as ways of fresh water supply in arid areas. Aims This paper aims to present and discuss to methods of water provision in the arid regions. These methods will be debated in terms of significance, cost and environmental impacts of the technique. Gulf Region Gulf region comprising the countries Iraq, Kuwait, Bahrain, Oman, Qatar, United Arab Emirates and Saudi Arabia have their economies largely dependent on oil, the region hosts over half of the world oil reserves. Because of this, they are generally reach with the exception of Iraq and Saudi Arabia, which receives little revenues from oil and gas as compared to the neighboring states. In addition to the oil wells, these countries gain significant revenues from marine business and pearl industry. However, the gains from pearl industry recorded significant decline since the 1930s with the Japanese’s development of cultured pearl methods. Back in the 1940s, a time when there was no adequate fresh water, no electricity and education, oil was discovered but people did not have the knowledge to exploit the resources until the Second World War. They slowly utilized their strength to mine oil, but no industrial activity could thrive without water. This led to the invention of ways to make water available for use; among the methods that came into play was desalination. Today, in spite the fact that these countries receive an average of 72mm of rainfall each year, they occupy the first position among the largest fresh water consumers. Background World water problem While human beings need water for survival and for industrial developments, some nation face water scarcity. This situation exist due to climatic changes such as drought or naturally by the region being a desert or arid. Water crisis exist when desired water cannot satisfy the region’s need for fresh water, this have been evidenced in many countries (Santos, 2009). Each nation is currently trying to reduce water scarcity and crisis by employing different methods including desalination and water recycling which are discussed in this paper. Presentation of options Desalination Desalination have been the source of clean and reliable water for the arid region for over five decades. The practice is all about extracting the salty seawater and running it through a chain of purification systems to remove the salt and other admixtures so that it is reversed to fresh water. Economic development in the Gulf region have only been possible with parallel development of water purification processes. The region gets 90% of its water from desalination. To perfect the science of desalination, a number of technologies have been brought to action including multi-stage flash desalination, reverse and forward osmosis, multi-effect desalination, Nano-filtration, electro-dialysis, low temperature and solar membrane desalination technologies. Thermal desalination processes have been observed to be less energy efficient as compared to other processes. With technological improvements, the capacity of thermal distillers have been increased from producing 7kg of fresh water from a kilogram of steam to 10kg of fresh water and the trend is expected to be maintained. Other methods such as osmotic methods, solar membrane, tri-hybrid distillation and low temperature methods pose a challenge to the traditional thermal desalination methods. The major challenge to desalination is the high amount of energy required to run the process and the need to make it environmental friendly. Solar energy is the next best alternative since the Gulf region and other arid areas experience the maximum amount of solar radiation. However, the high-energy requirement is still too high to be sufficiently catered for by solar power, not unless these ideas are taken care of technologically. Common methods of desalination Reverse osmosis- in this method, seawater is made to flow across a membrane with fine pores by application of high pressure and the salt residue are filtered by the membrane Forward osmosis- water is made to flow by natural osmosis, flow from a region of high concentration to a region of low concentration by placing a more concentered substance such as aluminum salt on one side and seawater on the other after which the water is heated to separate it from the salt Electrolysis- oppositely charged electrodes are used to remove the salt from water, in the process, the metallic contaminants move to the positive electrode and the ions to the negative electrode and clean water is extract from the middle portion Thermal desalination- the methods applied under this category include multi flash desalination (water that has already been purified is again purified at another pressure to reach perfection) and multi effect desalination (water is purified in stages of different at temperatures until it is safe) Conceptual diagram of desalination process Environmental impacts of desalination Even though the very salts that were abstracted from the sea are the ones being discharged back to the sea, the concentration at which they are being discharged is higher than normal hence causing osmotic imbalance. In addition to these, residual chlorine also finds its way into the sea and this may result into harmful effects over a longtime. Emphasis should be made on ways of mixing the discharged water with seawater to reduce local salt concentration and ways of reducing chemical concentration in the residue. Smoke produced by the burning fuel is also harmful to the environment. Cost of desalination The largest percentage of desalination funds are spent on power. Gulf region being an oil reach region, the fuel can be easily obtained. However, other costs that indirectly affect desalination such as pollution also come into play; it is regarded as exchanging of one environmental problem for another (Al-Karaghouli & Kazmerski, 2013).. The cost of transporting desalinated water to the interior parts of the countries is also high. Recycle water The quantity of wastewater produced in the Gulf region is surprising considering the fact that the region is classified as water stressed. With the desert nature of Gulf region, residents tends to use water luxuriously to the degree of 550liters of water per head. The industries use much higher than that. Because of this, a large proportion of desalinated water is quickly converted into wastewater, therefore, there is need to purify this water. Methods that have been employed to purify water includes the industrial technology and reed beds method. The industrial way involves water being pumped through filtering chambers that remove substantial amount of solid wastes, the water is then directed to three storage tanks in series which are loaded with sediments to filter the water father and then passed to the treatment tanks and finally to the storage tank. The reed bed method, which was initially tested in Europe, offers the most efficient way of recycling wastewater. Reed plants are planted on gravel filters and their roots allows for vertical percolation, inside the filters, special microbial activities that serve to break down organic pollutants take place cutesy of water plants that injects a lot of oxygen in the filters. Metallic pollutants are handled through cation exchange process, which converts them to mineral substrates for plant anchorage or humic acid. Studies reveal that recycled water is not fit for human consumption due to inability to eliminate the entire chemical compound or diseases causing organisms. However, the water can be used in irrigation and industries in order to reduce the need of desalinated water and hence fuel consumption. The methods of recycling water are also environmental friendly in numerous ways. Conceptual diagram of reed bed water recycling process Environmental effects of recycling water Recycled water contains chemicals that failed to be completely broken down in the recycling process. The byproducts can causes significant damages to the natural ecosystem. Chemicals added at the final stage of recycling including polymers and the usual content of slug such carcinogens and endocrine disrupting chemicals e.g. oestrogen, which are capable of harming aquatic life, for instance, the transgender fish, which was originally male but developed female organs (Darab, 2013).. The problem is much worse when the chemicals climb to higher organisms through irrigation of food crops. Costs of recycling water Just like desalination, power in needed to run water purification processes that must be given much consideration before establishing the plant. Other cost include land and personnel for the facility. However, water recycling is generally cheaper. Requirements of options Requirements for desalination- The process being fuel or electric power dependent requires immense availability of power, fuel for thermal processes and electricity for electrolysis method and reverse osmosis. Aluminum salt is required for forward osmosis. Material selection is also a matter of concern since seawater is highly corrosive. The high temperatures and chlorination involved in the process makes the situation even worst. As a result of this, corrosion resistant materials such as copper and nickel alloys, duplex steel and stainless steel alloys are used to make heat transfer channels and evaporating shells. Requirements for recycling water- water recycling method that involves industrial treatment requires construction of tanks and purification vessels. Chemicals are also needed to kill microorganisms in water. Reed bed method is largely biological and environmental friendly hence require the propagation of water plants such as reeds and structural design for the flow system. Chemicals are also needed at the final stage to treat the water before consumption Comparison of option Costs- the cost of desalination is much higher than the cost of wastewater purification since desalination must be accomplished industrially and with immense amounts of energy. In addition, recycled water may have originally been desalinated water and became wasteful in the process of usage; as a result, cost of extracting the water from the sea will be escaped if recycling process is employed. Initial cost of establishing a desalination firm is also higher than the cost of setting up recycling firm. Environmental impacts- The process of desalination involves use of oil or fuel, which produces carbon (ii) oxide when burnt. This gas is harmful and is capable of promoting global warming. However, the water produced through this process is safe for consumption. On the other hand, recycled water may retain some of the chemicals used in the process or the waste may not be eliminated and may find their way to human beings when used in irrigation. Environmentally, the method is friendly and no emission of greenhouse gases. If recycled water is used industrially, it has no negative effects if all salts were eliminated. Conclusion In the phase of global warming and the rising needs of fresh water to power machines and for domestic purposes. Arid areas neighboring seas such as the Gulf region needs to make use of locally available seawater to cover for its needs. Wasted water should also be taken care of through recycling so that it is applied is cases where pure water is not necessary like irrigation. Economic strengths of countries in Gulf region also gives them an upper hand in establishing desalination and water recycling firms. References Santos, L. (2009). Coping with Water Scarcity. Retrieved on 1/1/2014 Al-Karaghouli, A & Kazmerski, L. (2013). Energy consumption and water production cost of conventional and renewable-energy-powered desalination process. Renewable and Sustainable Energy Reviews. 24. Pp 343-356. Darab, C. (2013). An approach for industrial wastewater treatment process. Advances in Environmental Sciences. 5. 2. 234-238. Retrieved on 1/1/2014 Read More