ملخص الدراسة:

In Gaza, it is planned to construct one of the most important seawater desalination plant in the region of Levantine basin, the plant is named Gaza Central Seawater Desalination Plant (GCDP). In the short term, Phase (I), the plant will desalinate seawater for potable uses with a capacity of 55Mm3 per year, while in the long term another phase, Phase (II), will be operated to double the plant`s desalination capacity to 110Mm3 per year. As a product from the reverse osmosis process, a huge amount of brine with a salinity reaches 61ppt will be produced from GCDP, nearly 12,200m3/h of brine will be rejected from Phase (I) while in the long term brine`s flow rate of 24,400m3/h will be disposed from Phase (II). In this study numerical simulations beside sensitivity analysis were carried out to optimize a configuration design for the disposal system of GCDP. Three disposal scenarios have been modelled in this study, the first scenario simulates the rejected brine via surface channel at sea face, the second scenario concerns in the brine behavior disposed via submerged single port diffuser, while the third scenario interests in the brine disposal through offshore multiport diffuser. The results of the surface discharge show that no design meets the disposal regulations at the regulatory mixing zone (RMZ) for Phase (I) and Phase (II) simultaneously, but the channel’s width of 4m at a slope of 3% in winter and summer where the brine`s concentrations above ambient at RMZ in winter were 1105ppm and 1904ppm, whilst the results in summer were 1057ppm and 1782ppm for Phase (I) and Phase (II), respectively. For offshore submerged single port scenario, the results show that the disposal regulations at RMZ were met at all port dimeters in all seasons at offshore disposal distances of 1450m or more for Phase (I) and Phase (II), simultaneously, the brine`s concentrations above ambient at RMZ at a port diameter of 1m at 2050m offshore distance were 676 and 1071ppm in winter, 654 and 1028ppm in spring, 705 and 1122ppm in summer, and 646 and 1014ppm in autumn for Phase (I) and Phase (II), respectively. In the third scenario, this study provides an environmental and feasible design for the disposal system of GCDP, the configuration design of the disposal system can be characterized as 36 risers (144 ports), 20.5m spacing (717.5m+2.4m diffuser`s length), 573m outfall`s length, and outfall`s inclination angle (ø) 74o to coastline. Finally, in this study and according to the modelling results it is recommended to dispose the produced brine from GCDP through offshore multiport diffuser system extended far into the sea at a disposal depth equal to 9.5m. Multiport diffuser system is the optimal device which can minimize the negative effects of the brine on the marine ecosystem as well as it can dilute the brine in manner that can guarantee the quality of the feed seawater.

توثيق المرجعي (APA)