**Appendices and nomenclature**



**5. Conclusions**

364 Desalination and Water Treatment

injection, aeration need, etc.).

by numerical calculations.

**Acknowledgements**

*Ab* [mm<sup>2</sup>

*a* [mm<sup>2</sup>

**Appendices and nomenclature**

This chapter presents an experimental study for the global optimization of aeration in the industrial configuration. For optimization two main parameters were considered: aeration performance (dissolved oxygen transfer) and energy consumption for the air injection.

Was considered many injection devices: two series of metallic plates with different designs (the arrangement of aeration holes, hole shapes, and diameter) and hole diameters between 0.2 and 2.4 mm, ceramic plates, and glass plates in an air bubble column in water. The investigations where performed for the following air flow rates: *Q* = 180, 360, 480, 600, 720, 960, 1140 l/h. The aeration performances were obtained, using the procedure of the standard procedure ASCE 2-91/1993 (Kla and SOTR), and compared with other literature results. The

Based on these results and injection loss measurements, the SAE—standard aeration effi-

Taking into account these parameters in an aerator design, and optimizing the total efficiency, allows for an efficient deployment of aeration devices in industrial systems. As variations in efficiencies for dissolved oxygen transfer, or losses, in different aeration devices can be greater than a factor of 10, the findings of this optimization study are significant for achieving the best design of aeration systems for hydraulic turbines and in water treatment and so on in regulation to the specific needs and capacity of each application (available air flow rate, pressure of

This study shows the importance of the optimization of the aerator device in terms of materials, aperture arrangement, aperture shape, aperture dimension for the specific conditions of each application (air flow rate, pressure gradient, emplacement of the aeration device), and for the best global efficiency—best compromise between the energy needed for the injection

In the next step, these results and the detailed bubble flow morphology [12] will be used to validate numerical simulations for dissolved air transfer, to realize the sparger optimization

This works was performed in the frame of the project NUCLEU PN18240202, ctr. 24N/2018

of the air and the quantity of dissolved oxygen obtained by the aeration process.

ElectroEchipaMat, financed by the Ministry of Research and Innovation.

] area of an air bubble considered spherical

] interfacial area of the first swarm of bubbles

results are coherent for the tendencies and the differences were explained.

ciency—was calculated for all plates and global efficiency curves were plotted.


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