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Desalination
Published in P.K. Tewari, Advanced Water Technologies, 2020
Water containing salinity in the range of 1,000–20,000 ppm total dissolved solids (TDS) is generally known as brackish water. Different types of desalination processes are used to bring down the salinity of water. Brackish water desalination using a membrane process to get drinking quality water from saline water is practiced widely. There are several advantages of brackish water desalination by membrane process, such as low specific energy requirement and low-pressure membranes. It has short start-up and shutdown times. It can be easily integrated with renewable energy sources including solar, wind, tidal, etc. Technological innovations have brought down the specific energy consumption in brackish water RO considerably to about 1 kwh/m3. The incorporation of advanced membrane-based pretreatment technology such as microfiltration (MF) and ultrafiltration (UF) has the potential to increase plant recovery, reduce consumables required for operation and maintenance, reduce membrane cleaning frequency and increase membrane life.
The Water Nexus and Desalination
Published in Farid Benyahia, Membrane-Distillation in Desalination, 2019
The relative advantages of desalination: it is virtually climate change independent, and salty water (oceans, seas) is abundant and can be considered as a sustainable resource when wisely exploited. However, there are disadvantages of desalination: effects on the ecosystem (potential local salinity increases if rejects are not dispersed sufficiently, damage to marine life at intake if no precautions taken), energy intensity and carbon emissions (if fossil fuels are used). Some progress has been made to minimize effects on the ecosystem, and this will be briefly highlighted in later sections.
Abiotic Stress in Plants
Published in Hasanuzzaman Mirza, Nahar Kamrun, Fujita Masayuki, Oku Hirosuke, Tofazzal M. Islam, Approaches for Enhancing Abiotic Stress Tolerance in Plants, 2019
Ashutosh K. Pandey, Annesha Ghosh, Kshama Rai, Adeeb Fatima, Madhoolika Agrawal, S.B. Agrawal
Soil salinity reduces the productivity of many crops which have a low tolerance to soil salinity. The first morphological symptoms of salt stress are wilting, yellowing of leaves and stunted growth. In a second phase, the damage manifests as chlorosis of green parts, leaf tip burning, necrosis of leaves, and the oldest leaves display scorching (Shannon). Although plant species differ in their sensitivity or tolerance to salts (Marschner, 1995), high soil salinity has detrimental effects on seed germination and plant growth (Taiz and Zeiger, 2006) and in due course kills growing plants (Garg and Gupta, 1997).
Implementation and testing of a solar desalinator with water preheating
Published in International Journal of Ambient Energy, 2023
Thiagarajan Chinnappan, C. M. Raguraman
The uncertainty in solar radiation intensity depends on the accuracy of the angle measurement, and the variability in solar radiation intensity due to cloud cover or atmospheric conditions. The quality of the feedwater (seawater) can also affect the performance of the solar desalination. Changes in salinity, temperature, and other water quality parameters could affect the efficiency of the system and the quality of the desalinated water. The concentration of salt in the feedwater can be modelled using the following equation: where C is the concentration of salt in the feedwater, C0 is the initial concentration of salt, k is the salt removal rate, and x is the distance travelled by the feedwater. The uncertainty in feedwater quality depends on the accuracy of the measurements of the water quality parameters and the variability in these parameters over time.
Advances and challenges in solar-powered wastewater treatment technologies for sustainable development: a comprehensive review
Published in International Journal of Ambient Energy, 2022
In this process, the salinity of water is reduced by supplying electricity to the electrodialysis cell which removes the dissolved salts via the ion exchange membrane. The positive ions of saline water flow towards cathode side while the negative ions flow towards anode side (Wright 2014). The multiple electordialysis cells in ED stack are arranged in parallel to the flow using flow spacers (AlMadani 2003). In 1953, this technology was first used for commercial purposes in Saudi Arabia (Reahl 2006). Later, the influence of electric field on membrane stack was analysed and ED was reinvented as electordialysis reversal (EDR) for the fast removal of salt concentration from membranes. Unlike RO, the EDR eliminates the use of chemicals for the desalination process. AlMadani (2003) investigated the working performance of EDR unit in Bahrain and Spain. In Bahrain, the samples with varying salt concentrations (1000–5000 ppm) were analysed and reported a water yield of 1.14 m3/d (for SR > 95%). However, the higher value of SR can be attained at higher feed water temperature. The schematic diagram of EDR unit is shown in Figure 19.
Desalinated drinking-water provision in water-stressed regions: challenges of consumer-perception and environmental impact lessons from Antofagasta, Chile
Published in International Journal of Water Resources Development, 2022
M. Šteflová, S. H. A. Koop, M. C. Fragkou, H. Mees
The process of desalinization is associated with negative environmental impacts due to discharges into the marine environment (Dawoud & Al Mulla, 2012; Lattemann & Hopner, 2008; Petersen et al., 2018; Von Medeazza, 2005). If desalination discharge, or brine, is released into poorly flushed environments, the salinity and temperature of the receiving waters increases substantially (Dawoud & Al Mulla, 2012; Qdais, 2008). Brine, which has a higher density than seawater, spreads over the sea floor in shallow coastal waters unless it is dissipated, affecting benthic organisms and seagrass beds. A thermal effect can in turn affect water quality processes and result in lower dissolved oxygen concentrations. Long-term exposure to unfavourable conditions can have a long-lasting impact on species composition (Dawoud & Al Mulla, 2012). Furthermore, a number of contaminants can be released during the construction and operation of desalinization plants. These include reaction (by-)products, from diverse processes such as construction, corrosion, pretreatment and cleaning (Dawoud & Al Mulla, 2012; Hoepner & Lattemann, 2003; Roberts et al., 2010). This presents the potential for acute and chronic toxicity (Construvo et al., 2010).