Sulfide removal using ozone as an oxidizing agent in tannery wastewater
Abstract
In this study, the removal of sulfides in wastewater from the process of peeling or depilating skins was evaluated, using ozone as an oxidizing agent. The effect of the initial pH on the removal process was determined, for this purpose a completely randomized experimental design was used, in which the pH of the water was varied between 10, 11, 12 and 13, the ozone was dosed at a rate 0.5 g h-1 for a period of 3 hours taking samples every 30 minutes. The tests were performed for the real wastewater, supplied by a tannery and synthetic wastewater, in order to compare the removal achieved in each case. The analysis of the results obtained showed that the highest removal was achieved at pH 11 in the actual wastewater, reaching a value of 77.78%, approximately 39% higher than that reached at the same pH for the synthetic wastewater. The kinetics of the process were also evaluated, obtaining that the results are adjusted to a kinetic of pseudo first order for which the kinetic coefficient was -0,0001 s-1, finally, it was observed that after each test there was a decrease pH, which confirms what chemically should happen, formation of H2SO4 by the oxidation of sulphides to sulfates. Finally, it is concluded that the removal of sulfides using ozone is a technique applicable for alkaline pH, allowing to reduce oxidation times and becoming a viable alternative to apply in the leather tanning industry.
Keywords
advanced oxidation, clearing, ozone, removal, sulfur, tanning
References
[1] S. Jian, T. Wenyi, and C. Wuyong, “Kinetics of enzymatic unhairing by protease in leather industry,” Journal of Cleaner Production, vol. 19 (4), pp. 325-331, Mar. 2011. DOI: https://doi.org/10.1016/j.jclepro.2010.10.011.
[2] Gobernación de Cundinamarca, Diagnóstico económico, ambiental y social de los curtidores de Choconta y Villapinzon (Cundinamarca). Bogotá D.C.: Gobernación de Cundinamarca, 2014.
[3] L. H. Wei Xu, and J. Zhang, “Hair-saving Enzyme-assisted Unhairing: Effects of Sodium Hydrosulfide and Peroxide.,” in 32nd Congress of the International Union of Leather Technologists and Chemist Societies, Istanbul, 2009.
[4] Linde Ecuador S.A., Hoja de seguridad del material (SDS) sulfuro de hidrógeno - Producto químico e identificación de la empresa, 2012. Available: http://www.linde-gas.ec/en/images/HOJA%20DE%20SEGURIDAD%20SULFURO%20DE%20HIDROGENO_tcm339-98247.pdf.
[5] G. Salas, “Eliminación de sulfuros por oxidación en el tratamiento del agua residual de una curtiembre,” Rev. Per. Quím. Ing. Quím, vol. 8 (1), pp. 49-54, 2005.
[6] Q. Imran, M. A. Hanif, M. S. Riaz, S. Noureen, T. M. Ansari, and H. N. Bhatti, “Coagulation/Flocculation of Tannery Wastewater Using Immobilized Chemical Coagulants,” J. Appl. Res. Technol., vol. 10 (2), pp. 79-86, 2012.
[7] S. Sundarapandiyan, R. Chandrasekar, B. Ramanaiah, S. Krishnan, and P. Saravanan, “Electrochemical oxidation and reuse of tannery saline wastewater,” Journal of Hazardous Materials, vol. 180 (1-3), pp. 197-203, Aug. 2010. DOI: https://doi.org/10.1016/j.jhazmat.2010.04.013.
[8] L. Bilińska, K. Blus, M. Gmurek, and S. Ledakowicz, “Coupling of electrocoagulation and ozone treatment for textile wastewater reuse,” Chemical Engineering Journal, vol. 358, pp. 992-1001, Feb. 2019. DOI: https://doi.org/10.1016/j.cej.2018.10.093.
[9] D. E. Brune, and R. L. Perez, “A continuously regenerated greensand filter for H 2 S removal from individual water supplies,” J. Environ. Sci. Heal. Part A Environ. Sci. Eng. Toxicol., vol. 25 (1), pp. 1-20, Jan. 1990.
[10] Y. Tzvi, and Y. Paz, “Highly efficient method for oxidation of dissolved hydrogen sulfide in water, utilizing a combination of UVC light and dissolved oxygen,” Journal of Photochemistry and Photobiology A Chemistry, vol. 372, pp. 63-70, Mar. 2019. DOI: https://doi.org/10.1016/j.jphotochem.2018.12.005.
[11] S. Venkatesh, K. Venkatesh, and A. R. Quaff, “Dye decomposition by combined ozonation and anaerobic treatment: Cost effective technology,” Journal of Applied Research and Technology, vol. 15 (4), pp. 340-345, Aug. 2017. DOI: https://doi.org/10.1016/j.jart.2017.02.006.
[12] F. J. Rodríguez Vidal, Procesos de potabilización del agua e influencia del tratamiento de ozonización. Madrid: Ediciones Díaz de Santos, 2003.
[13] J. Pey Clemente, “Aplicación de procesos de oxidación avanzada (fotocatálisis solar) para tratamiento y reutilización de efluentes textiles,” Thesis, Universidad Politécnica de Valencia, 2008.
[14] N. Ramírez-Ramírez, M. C. Espinosa-Lloréns, L. A. Fernández-García, E. Véliz-Lorenzo, and Y. Ramos-Rodríguez, “Treatment with Ozone of Wastewater Containing Tannins from Vegetal Tannery,” Water Technol. Sci. (in Spanish), vol. 7 (3), pp. 53-73, 2016.
[15] K. Sivagami, K. P. Sakthivel, and I. M. Nambi, “Advanced oxidation processes for the treatment of tannery wastewater,” Journal of Environmental Chemical Engineering, vol. 6 (3), pp. 3656-3663, Jun. 2018. DOI: https://doi.org/10.1016/j.jece.2017.06.004.
[16] Instituto Nacional de Ecología, Manual de procedimientos para el manejo adecuado de los residuos de curtiduría. Ciudad de México: Instituto Nacional de Ecología, 1999.
[17] A. P. H. Association, Standard Methods For the Examination of Water and Wastewater. Maryland, 2012.
[18] C. Von Sonntag, and U. Von Gunten, Chemistry of Ozone in Water and Wastewater Treatment. London: IWA Publishing, 2012.