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Confined plunging jets are investigated as potential outfalls for the discharge of desalination brine. Compared to offshore submerged outfalls that rely on momentum to induce mixing, plunging jets released above the water surface utilize both momentum and negative buoyancy. Plunging jets also introduce air into the water column, which can reduce the possibility of hypoxic zones. In contrast to unconfined plunging jets, confined plunging jets include a confining tube, or downcomer, around the jet, which increases the penetration depth of the bubbles and can provide better aeration. However, the presence of this downcomer can hinder mixing with surrounding water. Therefore, laboratory measurements of dilution are reported here and compared to the dilution of unconfined plunging jets. In addition, qualitative observations of bubble penetration depth are also used to discuss aeration potential. For designs that increase the bubble penetration depth as compared to unconfined plunging jets, results show that dilution decreases as the depth of the downcomer is increased. However, it is shown that confined plunging jets can be designed with a short downcomer to provide higher dilution than unconfined jets. The effect of the diameter of downcomer on dilution is also investigated and a non-monotonic effect is observed.
Ishita Shrivastava; Edward Adams; Bader Al-Anzi; Aaron Chow; Jongyoon Han. Confined Plunging Liquid Jets for Dilution of Brine from Desalination Plants. Processes 2021, 9, 856 .
AMA StyleIshita Shrivastava, Edward Adams, Bader Al-Anzi, Aaron Chow, Jongyoon Han. Confined Plunging Liquid Jets for Dilution of Brine from Desalination Plants. Processes. 2021; 9 (5):856.
Chicago/Turabian StyleIshita Shrivastava; Edward Adams; Bader Al-Anzi; Aaron Chow; Jongyoon Han. 2021. "Confined Plunging Liquid Jets for Dilution of Brine from Desalination Plants." Processes 9, no. 5: 856.
Brine discharges from desalination plants into low-flushing water bodies are challenging from the point of view of dilution, because of the possibility of background buildup effects that decrease the overall achievable dilution. To illustrate the background buildup effect, this paper uses the Arabian (Persian) Gulf, a shallow, reverse tidal estuary with only one outlet available for exchange flow. While desalination does not significantly affect the long-term average Gulf-wide salinity, due to the mitigating effect of the Indian Ocean Surface Water inflow, its resulting elevated salinities, as well as elevated concentrations of possible contaminants (such as heavy metals and organophosphates), can affect marine environments on a local and regional scale. To analyze the potential effect of background salinity buildup on dilutions achievable from discharge locations in the northern Gulf, a 3-dimensional hydrodynamic model (Delft3D) was used to simulate brine discharges from a single hypothetical source location along the Kuwaiti shoreline, about 900 km from the Strait of Hormuz. Using nested grids with a horizontal resolution, comparable to a local tidal excursion (250 m), far field dilutions of about 28 were computed for this discharge location. With this far field dilution, to achieve a total dilution of 20, the near field dilution (achievable using a submerged diffuser) would need to be increased to approximately 70. Conversely, the background build-up means that a near field dilution of 20 yields a total dilution of only about 12.
Aaron C. Chow; Wilbert Verbruggen; Robin Morelissen; Yousef Al-Osairi; Poornima Ponnumani; Haitham M. S. Lababidi; Bader Al-Anzi; E. Eric Adams. Numerical Prediction of Background Buildup of Salinity Due to Desalination Brine Discharges into the Northern Arabian Gulf. Water 2019, 11, 2284 .
AMA StyleAaron C. Chow, Wilbert Verbruggen, Robin Morelissen, Yousef Al-Osairi, Poornima Ponnumani, Haitham M. S. Lababidi, Bader Al-Anzi, E. Eric Adams. Numerical Prediction of Background Buildup of Salinity Due to Desalination Brine Discharges into the Northern Arabian Gulf. Water. 2019; 11 (11):2284.
Chicago/Turabian StyleAaron C. Chow; Wilbert Verbruggen; Robin Morelissen; Yousef Al-Osairi; Poornima Ponnumani; Haitham M. S. Lababidi; Bader Al-Anzi; E. Eric Adams. 2019. "Numerical Prediction of Background Buildup of Salinity Due to Desalination Brine Discharges into the Northern Arabian Gulf." Water 11, no. 11: 2284.