Elma-Asterion Group of Companies, Saint Petersburg, Russia

А. N. Grigorieva, General Director, Candidate of Technical Sciences, an@td-elma.ru
А. V. Anufriev, Research and Development Specialist, aav@ast-pump.ru

The metallurgical industry, including non-ferrous metallurgy enterprises, is one of the largest water consumers and sources of wastewater generation. The discharges contain heavy metal ions (copper, nickel, zinc, lead), suspended solids, petroleum products, and flotation reagents, which requires the use of multi-stage and energy-intensive purification schemes. A key factor in the effectiveness of physical and chemical and biological methods of water treatment is high-quality mixing, ensuring an even distribution of reagents, maintaining floccules in suspension and preventing siltation of containers. One of the most effective means of creating directional circulation in largecapacity tanks and aerotanks is submersible horizontal mixers (SHM), performance of which is directly determined by the amount of axial thrust generated. Optimization of the geometry of the SHM blades to maximize thrust with minimal energy consumption is an urgent scientific and technical task. The main purpose of this article is to define criteria for creating an energy-efficient mixer geometry based on the recommendations of the propeller design theory, taking into account the global experience of well-known manufacturers. The efficiency parameters have been determined experimentally on a special stand that allows measuring the thrust and productivity of the mixer to calculate key indicators.

1. Bocharov V. A., Ignatkina V. A., Kayumov A. A. Theory and practice ofmine ral separation of massive refractory polymetallic ores of non-ferrous metals : monograph. Moscow : Gornaya kniga, 2019. 510 p.
2. Braginsky L. N., Evilevich M. A., Begachev V. I. et al. Modeling of aeration facilities for wastewater treatment. Leningrad : Khimiia, 1980. 144 p.
3. Popov N. V., Grigorieva A. N., Zaletov S. V. Experience of reconstruction of sewage treatment plants of Municipal Unitary Enterprise “Teplovodokanal” in Pushchino. Vodosnabzheniye i sanitarnaya tekhnika. 2022. No. 8. pp. 21–27.
4. Bazhenov V. I. Optimization criterion for aerotanks with longitudinal recirculation of sludge carousel-like mixture. Ekologiya i promyshlennost Rossii. 2008. No. 12. pp. 20–23.
5. Bazhenov V. I. Submersible mixers as a promising area of scientific research. Inzhenerniy vestnik. 2015. No. 1. pp. 19–28.
6. ISO 21630:2007. Pumps - Testing - Submersible mixers for wastewater and similar applications. First edition. Geneva, 2007. 24 p.
7. Belova О. А. Reconstruction of sewage treatment plants in Perm. Voda: khimiia o ekologiya. 2014. No. 1. pp. 118–122.
8. Bazhenov V. I., Bozhyeva S. M., Lomakin V. O. Influence of design parameters of a high-speed mixer on its energy characteristics. Nasosy. Turbiny. Sistemy. 2020. No. 4. pp. 9–17.
9. Gordeev S. WILO high-efficiency mixers for wastewater treatment. Nailushchye dostupnye tekhnologii vodosnabzheniya i vodootvedeya. 2014. No. 2. pp. 4–6.
10. Antonenko S. V. Ship propulsion systems : a textbook. Vladivostok : DVGTU, 2007. 131 p.
11. Carlton J. S. Marine propellers and propulsion. 3^rd ed. Oxford : Butterworth-Heinemann, 2012. 536 p.
12. RD 26-01-90–85. Mechanical mixing devices. Calculation method. Introduced: 01.01.1985. Moscow : Standards Publishing House, 1985. 45 p.
13. Idelchik I. E. Handbook of hydraulic resistance. Moscow : Mashinostroeniye, 1992. 672 p.