Brackish water desalination systems integration

ED for treating low TDS brackish waters and industrial waters is a proven and cost-efiective technology, and in some applications superior to RO and NF [33,34,37]. Integrated RO/EDR, NF/EDR [47] and RO-ZDD [48] systems can reduce the cost of treated water by achieving higher recovery, e.g. in the case ofinland brackish water desalination, higher total recovery results in minimising brine concentrate volume for disposal (see Chapter 3). 

Electrodialysis/electrodialysis reversal (ED/EDR) represents 3% of aU the desalination capacity in the world [48]. It is, however, used mainly for desalinating brackish water. It can achieve 95% water recovery with minimal chemical feed. However, it can only reject ionised matter. Substances such as colloids, silica and boron at pH <8.0 are not removed. A triple-membrane system using UF-EDR-RO has been very effective in producing purified water for power plants [50]. In this integrated system, UF is used for removing suspended solids and macromolecules ... 

Integration of brackish and seawater desalination systems. In many places brackish water can be found close to the sea. Integrating the two types of desalination may reduce the cost of the final product. 

Furthermore, water scarcity has led to the widespread use of desalination to supplement freshwater resources. While reverse osmosis (RO) membranes are used to desalinate seawater and brackish water, MF/UF can be applied as a pretreatment to RO, in an integrated membrane system (IMS). The level of pretreatment, in terms of turbidity and silt density index (SDI), provided by MF/UF was found to be significantly better and more consistent than conventional pretreatment to RO (e.g., coagulation/sedimentation/filtration) for RO feed water. In recent years, the demand for MF/UF as a pretreatment to RO has grown as the need to augment our... 

Due to the low rejection of monovalent salts, osmotic pressures in NF are lower than in RO. Thus, lower pressures need to be applied, and the energy consumption is proportionally lower. RO membranes operable at ultralow pressures have been developed (Semiat, 2000 Matsuura, 2001) that allow the desalination of brackish water at pressures comparable to those applied in NF. These membranes operate at the interface of NF and RO and might be helpful in optimizing the desalination process. Hassan et al. (1998) reported the use of NF in an integrated desalination system NF-SWRO (sea water reverse osmosis) and... 

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