Introduction
In many areas of the Middle East, the proper functioning of the vital social mechanism depends on the stable supply of fresh water. In the case of Qatar, this supply is provided by the implementation of advanced desalination plants. However, despite the technological superiority of modern stations, they still remain subject to adverse external influence. This degree of vulnerability is entailed by the vital nature of desalination plants. As such, the oil spills in the Gulf remain one of the most serious hazards for Qatar’s freshwater supply in the 21st century. The contamination of water entails adverse consequences in several ways. First of all, it pollutes the Gulf itself, thus affecting the very source of such a vital resource. At the same time, oil-polluted water changes its physical properties, meaning that the essential elements of the equipment can be damaged. In order to mitigate the complications of oil spills, desalination plants devise various techniques of oil and water separation. This paper discusses the implementation of these approaches in desalination plants in Qatar.
Desalination in Qatar
The question of access to clean, potable water remains topical in the 21st century. Despite the unprecedented level of technological and social development, certain parts of the world continue to exhibit a serious shortage of stable freshwater supply. Qatar is one of the nations that retain such a need, as enabled by the geographical and climate conditions. According to Rahman and Zaidi (2018), the desalination campaign in Qatar has been developing since 1955. Evidently, across more than a half-century, the technology has evolved. Throughout this period, the desalination plant function has been associated with serious environmental concerns related to the increasing brine discharge (Rahman & Zaidi, 2018). However, the industry has currently been implementing reverse osmosis (RO) technology. One of the benefits of this approach consists of the advanced processing of brine, thus mitigating the environmental impact of the process (Darwish et al., 2012).
On the other hand, the expansion of the RO-based desalination industry entails a higher degree of vulnerability of the system itself. With a higher number of stations, potential oil spills in the Gulf and Arabian sea pose serious risks of malfunctioning through pollution. As a result, the industry’s decision-makers are prompted to work on efficient solutions that allow them to maintain a stable supply of freshwater in Qatar despite possible hazards.
Oil and Water Separation Techniques
One of the key objectives in terms of the anti-spill protection of desalination plants is to separate water from oil. In this regard, the removal of suspended solids and oil particles is the primary yet difficult objective (Judd et al., 2014). Saththasivam et al. (2016) discuss the existing variety of separation procedures that can be implemented in different settings, including desalination plants. First of all, some enterprises utilize the principle of a hydro cyclone, meaning that centrifugal forces move the water mass, allowing physics to remove from the core of the vortex due to its lower density. According to Saththasivam et al. (2016), this approach enables a “high throughput with very low retention time” (p. 674). However, it struggles to maintain a similar level of effectiveness in the case of heavy oil and stable emulsions. Modern scientists provide a chemical alternative, which consists of adding coagulants and flocculants to coalesce and aggregate the particles of oil in the water mass. Nevertheless, the costs of its implementation, namely the purchasing of chemical solutions and maintenance of pumps, are rather expensive. As a result, the use of chemical separation entails serious expenditures.
At the same time, there exist other approaches to oil removal from water that are based on physics. Gravity is the central force of this process, namely the specific gravity affecting immiscible fluids (Saththasivam et al., 2016). The gravity-based techniques enable the separation of large quantities of suspended oil in considerable water masses. The methodology of this approach relies on the differences in fluid density, which, under the right circumstances, enables an effective solution to the discussed issue. The equipment requirements are also not as significant as for the previously mentioned approaches. Consequently, the gravity settling in all its variety is a cost-effective method of water and oil separation.
Considering the continuous development of the industry and the remaining hazards, the field continues to work in constant pursuit of new techniques. As such, Saththasivam et al. (2016) discuss the specific details of the gas flotation method. According to the authors, this technique consists of using a floating mechanism that reduces the density of oil particles by concealing them within gas bubbles. The method effectively removes lighter and smaller particles that would otherwise evade the means of gravity. In addition, the systems are compact and easily transported in case of necessity. The disadvantages of the method consist of its reduced cost-effectiveness, which makes it less favorable for the industry of water desalination.
Oil and Water Separation Procedure
In spite of the existing variety of oil and water separation techniques, the area of water desalination continues to rely on well-tested, cost-effective methods. In Qatar, desalination facilities execute uninterrupted monitoring of the seawater intake in order to detect the first traces of oil contamination. Once such traces are observed, operators urgently reduce the speed and volume of the intake. Simultaneously, certified experts take seawater samples and conduct the analysis to determine the scale of contamination. Using the laboratory-obtained data, forecasts are made regarding the development of the situation. Subsequently, some intake gates are disabled, and the contaminated water is pushed toward them with special jets. This procedure serves to prevent the entry of oil-mixed water into the potable water tanks.
In order to ensure its proper execution, the staff members search for the signs of contamination in the treated water chambers. The specific smell of oil is one of the primary signs indicating that the integrity of potable water has been breached. Starting from the 0.50PPM contamination level, the advisory board may recommend disabling the desalination plant in its entirety. Simultaneously, mechanical skimmers are deployed on sight, gathering the droplets and gradually reducing the degree of contamination. Following these procedures, the staff uses oil booms and adsorbing pads to eradicate the remaining traces of the unwanted substance. All available resources remain in standby mode while the lab experts continue to run contamination tests. The operations of the plant can be resumed only once the multi-level analysis confirms the absence of oil or any risks of further contamination of potable water.
Conclusion
Ultimately, the vital status of desalination plants for the people of Qatar makes it necessary to create and maintain effective oil and water separation techniques. In this context, the decision-makers’ arsenal includes methods that are based on physical, chemical, or other principles. However, while the variety of separation techniques is considerable, the desalination industry of Qatar values cost-effectiveness above all. As a result, the gravity-based skimming procedures complemented by absorbing pads and oil booms remain at the core of the emergency protocol. Its proper implementation, combined with further rigorous research, can ensure a stable supply of potable fresh water to the residents of Qatar and other regions.
References
Darwish, M., Hassabou, A. K., & Shomar, B. (2012). Using Seawater Reverse Osmosis (SWRO) desalting system for less environmental impacts in Qatar. Desalination, 309, 113–124. Web.
Judd, S., Qiblawey, H., Al-Marri, M., Clarkin, C., Watson, S., Ahmed, A. & Bach, S. (2014). The size and performance of offshore produced water oil-removal technologies for reinjection. Separation and Purification Technology, 134, 241–246.
Rahman, H., & Zaidi, S. J. (2018). Desalination in Qatar: Present status and future prospects. Civil Engineering Research Journal, 6(5), 1–7.
Saththasivam, J., Loganathan, K., & Sarp, S. (2016). An overview of oil–water separation using gas flotation systems. Chemosphere, 144, 671–680. Web.