ELECTROFLOTATION TREATMENT OF DAIRY WASTEWATER: CHEMICAL-TECHNOLOGICAL ASPECTS
Experimental researches are carried out and chemical-technological laws of reagent-electroflotation treatment of sewage of dairies are established. The wastewater of the milk processing enterprise of Sumy region was selected for the study. For reagent wastewater treatment, ferric chloride FeCl3 in the form of a 5% aqueous solution is selected. To accelerate the hydrolysis of the reagent as an alkaline additive was used calcium oxide (lime) CaO in dry form and sodium hydroxide NaOH in the form of 5% aqueous solution. To accelerate the formation of sediment (sludge) used flocculant nonionic polyacrylamide (PAA) in the form of 0.05% aqueous solution. The efficiency of treatment was studied by the following indicators of wastewater: hydrogen pH, transparency and amount of ether-soluble substances. It is established that the process of extraction of ether-soluble substances largely depends on the pH of the medium and increases with increasing alkalinity of wastewater. The greatest influence of pH of the environment is observed at concentration of FeCl3 of 100-150mg / dm3. When FeCl3 is added at a concentration of 200mg / dm3, the purification effect does not depend on the pH of the medium. The most effective is the addition of ferric chloride and then lime. Initially, the addition of FeCl3 coagulates proteins and partially demulsifies the fat emulsion. After the introduction of lime into the water, hydrolysis and formation of iron hydroxide Fe(OH)3 occurs, on the surface of which contaminants are adsorbed. The greatest degree of purification from ether-soluble substances 87-88% is provided by addition of ferric chloride FeCl3 in concentration of 150-200mg / dm3 at pH of 9,5-10. It was found that when using lime to increase the pH of wastewater at a concentration of 500mg / dm3, there is a more efficient removal of ether-soluble substances and suspended solids (increased transparency), and less sediment is formed. Summarizing the obtained data, the optimal concentrations of reagents for pre-treatment of wastewater were selected – FeCl3 - 100mg / dm3, CaO - 500mg / dm3 and wastewater pH - 7.2. It is shown that the reduction of the content of ether-soluble substances to 40mg / dm3 (at the maximum permissible concentration for dairy wastewater 50mg / dm3) is possible only at high processing time (20-30 minutes) and density (0.05A / cm2) and voltage (26 V) electric current, which leads to high electricity consumption.
2. Shevchenko, T.A., Shevchenko, A.A. (2015). Experimental study of intensification of the process of pressure flotation during wastewater treatment of a milk processing enterprise, Eastern European Journal of Advanced Technologies, 1/6 (79), 4-12.
3. Andronov, V. A., Makarov, Ye. O., Danchenko, Yu. M., Obizhenko, T.M. (2020). Research of the regularities of forming and chemical composition of sewage water of a dairy processing company, Technogenic and ecological safety, 7, (1/2020), 13-21.
4. Makarov, Ye. O. (2020). Environmentally friendly high-concentration waste waters of milk processing plants, Sustainable Development - Status and Prospects: Proceedings of the II International Symposium SDEV’2020. Lviv, 235-236.
5. Konevych, M., Hud, V. (2011). Features of dairy wastewater, Proceedings of the XV scientific conference of TNTU named after Ivan Pulyuy. Ternopil, 309.
6. Gerson de Freitas Silva Valente, Regina Celia Santos Mendonca, Jose Antonio Marques Pereira (2015). The efficiency of electrocoagulation using aluminum electrodes in treating wastewater from a dairy industry, Ciencia Rural, Santa Maria, 45, 9, 1713–1719.
7. Chezeau, B., Boudriche, L., Vial, C. and Boudjemaa, A. (2019). Treatment of dairy wastewater by electrocoagulation process: Advantages of combined iron/aluminum electrodes (published online 15.07.2019), Separation Science and Technology, 15.
8. Aitbara, A., Cherifi, M., Hazourli, S. and Leclerc, J.-P. (2016). Continuous treatment of industrial dairy effluent by electrocoagulation using aluminum electrodes, Desalination and Water Treatment, 57, 8, 3395-3404.
9. Benaissa, F., Kermet-Said, H. and Moulai-Mostera, N. (2016). Optimization and kinetic modeling of electrocoagulation treatment of dairy wastewater, Desalination and Water Treatment, 57, 13, 5988-5994.
10. Varank, G., Sabuncu, M.E. (2015). Application of Central Composite Design approach for dairy wastewater treatment by electrocoagulation using iron and aluminum electrodes: modeling and optimization, Desalination and Water Treatment, 56, 1, 33-54.
11. Ozornova, A.V. (2016). Investigation of the flotation process of dairy production wastewater treatment and development of a method for its intensification, Youth scientific and technical bulletin, 11, 20.
12. Ternovska, O. I., Kovtun, S. B., Kukushkin, A. I., Diakonov, V. I., Chebotariova, O. V., Fesenko, H. V. (2015). Treatment of industrial effluents of enterprises for processing livestock products from fat, Municipal economy of cities, 124, 39-42.
13. Brodskii, V. A., Kisilenko, P. N., Kolesnikov, V. A., Gordienko, M. G. (2016). Electroflotation extraction of protein suspensions from aqueous solutions, Advances in chemistry and chemical technology, XXX, 3, 46-48.
14. Kalinina-Shuvalova, S. F. (2013). Dairy industry wastewater treatment by flotation, New ideas of the new century: materials of the international scientific conference FAD TOGU, 2, 304-308.
15. Kalinina-Shuvalova, S. F., Kritskaia, A. F. (2013). Technological schemes for the treatment of greasy wastewater, Far East: problems of development of the architectural and construction complex, 1, 313-319.
16. Sukharev, Yu. I., Gofman, V. R., Nikolaienko, Ye. V., Abdrashitov, R. R. (1999). Investigation of the process of electroflotation of fats from wastewater, Bulletin of the Chelyabinsk Scientific Center of the Ural Branch of the Russian Academy of Sciences, 1, 121-130.
17. Physicochemical methods of wastewater treatment of dairy industry enterprises, Whole milk industry: overview information TSNIITEImyasomolprom, 44.
18. Matov, B. M., Napadenskii, R. Ya. (1985). Electrochemical stability of anode materials in the process of electrochemical wastewater treatment, Methods for the analysis of natural and waste water treatment, 47-49.
19. Iliin, V. I. (2014). Electroflotation. Development ways, Electroplating and surface treatment, 22, 4, 49-52.
20. Iliin, V. I., Brodskii, V. A., Kolesnikov, V. A. (2015). Development of technological solutions for wastewater treatment from organic pollution, Water treatment. Water treatment. Water supply, 4, 16-19.
21. Karataiev, O. R., Shamsutdinova, Z. R., Khafizov, I. I. (2015). Wastewater treatment by electrochemical methods, Technological University Bulletin,18, 22, 21-23.
22. Lurie, Yu. Yu. (1984). Analytical chemistry of industrial wastewater, M.: "Chemistry", 448.
The authors who publish in this collection agree with the following terms:
• The authors reserve the right to authorship of their work and give the magazine the right to first publish this work under the terms of license CC BY-NC-ND 4.0 (with the Designation of Authorship - Non-Commercial - Without Derivatives 4.0 International), which allows others to freely distribute the published work with a mandatory reference to the authors of the original work and the first publication of the work in this magazine.
• Authors have the right to make independent extra-exclusive work agreements in the form in which they were published by this magazine (for example, posting work in an electronic repository of an institution or publishing as part of a monograph), provided that the link to the first publication of the work in this journal is maintained. .
• Journal policy allows and encourages the publication of manuscripts on the Internet (for example, in institutions' repositories or on personal websites), both before the publication of this manuscript and during its editorial work, as it contributes to the emergence of productive scientific discussion and positively affects the efficiency and dynamics of the citation of the published work (see The Effect of Open Access).