y the evaluated treatments is significant. The T8 and T12 treatments were the ones that obtained the highest percentage of removal, however, the difference between these two removal percentages was not significant, therefore, the T12 treatment was taken (j = 22 mA/cm2, pH = 6) as the best due to the fact that it operated under conditions closer to neutrality, unlike the T8 treatment that operated with a pH value of 4.5 (Figure 3).

Under the operating conditions of the T12 treatment, a 68% removal of the initial COD was achieved, which generated an effluent with 297 mg/L COD.

Figure 3. Analysis of variance between treatments.

Authors such as Norma et al. [18],and Ukundimana [19] have reported greater efficiencies in COD removal (75% - 92%) when applying anodic oxidation on pretreated leachates. However, both studies used BDD electrodes as cathode and anode, which are more expensive and require a more delicate handling. The use of graphite electrodes in pretreated leachate was reported by Feki et al. [20],but with a low COD removal (22%), far removed from that achieved in the present study (68%). Obtaining better removal efficiencies at a greater j can be explained by the increase in the diffusion flow of organic matter from the anode, allowing a more efficient oxidation of organic compounds [21]. Whereas, authors such as Chiang et al. [22],point out that larger j increases the generation of oxidizing chlorine species, which further favor the elimination of pollutants.

Regarding Color removal, Figure 4 shows that during the five hours of reaction under the conditions of the T12 treatment, color was reduced by 90%, obtaining a final effluent with 158 Pt-Co. This decrease can be related to the degradation of humic and fulvic acids that gives color to leachates and are susceptible to oxidation by hydroxyl radicals produced in anodic oxidation [23]. In addition, although maximum color removal was achieved with the higher pH value, it still remained acidic (pH = 6), and according to Anglada [12],acidic conditions in the treatment of wastewater by anodic oxidation favors the release of certain oxidants such as Cl, Cl2 or HOCl in the anode, which can act directly on the species that give color to the leachate, resulting in better efficiencies in color removal. In general terms, after five hours of electrolysis, and by increasing j from 7 to 22 mA/cm2, the removal rate increased from 30% to 68% in COD and from 76% to 91% in Color.

4. Conclusions

Anodic Oxidation using graphite electrodes as cathode and anode was effective in removing recalcitrant organic matter present in pretreated leachate, reaching 68% in COD and 91% in color, representing a quality in the final effluent of 271 mg/L and 151 Pt-Co in COD and color, respectively, where the best removal conditions were achieved at a j of 22 mA/cm2 and pH of 6.

Figure 4. Color removal efficiencies at 5 hours of reaction.

According to the results obtained, anodic oxidation can be a viable and economical alternative with the use of graphite electrodes, as a stage of purification in the final treatment of pretreated leachates.

Conflicts of Interest

The authors declare no conflicts of interest regarding the publication of this paper.

Cite this paper

Sánchez-Sánchez, T.J., Nájera-Aguilar, H.A., Gutiérrez-Hernández, R.F., García-Lara, C.M., Araiza-Aguilar, J.A., Bautista-Ramírez, J.A. and Castañón- González, J.H. (2020) Application of Anodic Oxidation with Graphite Electrodes in Pretreated Leachates. Open Journal of Applied Sciences, 10, 69-77. https://doi.org/10.4236/ojapps.2020.103006


  1. 1. Bolyard, S.C. and Reinhart, D.R. (2016) Application of Landfill Treatment Approaches for Stabilization of Municipal Solid Waste. Waste Management, 55, 22-30. https://doi.org/10.1016/j.wasman.2016.01.024

  2. 2. Renou, S., Givaudan, J.G., Poulain, S., Dirassouyan, F. and Moulin, P. (2008) Landfill Leachate Treatment: Review and Opportunity. Journal of Hazardous Materials, 150, 468-493. https://doi.org/10.1016/j.jhazmat.2007.09.077

  3. 3. Torres, P., Barba, L.E., Ojeda, C., Martínez, J. and Castano, Y. (2014) Influence of Leachates Age on Its Physico-Chemical Composition and Toxicity Potential. La Revista U.D.C.A Actualidad & Divulgación Científica, 17, 245-255. https://doi.org/10.31910/rudca.v17.n1.2014.960

  4. 4. Luna, Y., Otal, E., Vilches, L., Vale, J., Querol, X. and Fernández, C. (2007) Use of Zeolitised Cal Fly Ash for Landfill Leachate Treatment: A Pilot Plant Study. Waste Management, 27, 1877-1883. https://doi.org/10.1016/j.wasman.2006.10.016

  5. 5. Costa, A.M., Alfaia, R.G.D.S.M. and Campos, J.C. (2019) Landfill Leachate Treatment in Brazil: An Overview. Journal of Environmental Management, 232, 110-116. https://doi.org/10.1016/j.jenvman.2018.11.006

  6. 6. Cabeza, A., Urtiaga, A., Rivero, M.J. and Ortiz, I. (2007) Ammonium Removal from Landfill Leachate by Anodic Oxidation. Journal of Hazardous Materials, 144, 715-719. https://doi.org/10.1016/j.jhazmat.2007.01.106

  7. 7. Bautista-Ramírez, J.A., Gutiérrez-Hernández, R.F., Nájera-Aguilar, H.A., Martínez-Salinas, R.I., Vera-Toledo, P., Araiza-Aguilar, J.A., Méndez-Novelo, R. and Rojas-Valencia, M.N. (2018) Biorreactor empacado con materiales estabilizados (BEME), como pretratamiento para lixiviados de rellenos sanitarios. Revista Mexicana de Ingeniería Química, 17, 561-571. https://doi.org/10.24275/uam/izt/dcbi/revmexingquim/2018v17n2/Bautista

  8. 8. Umar, M., Aziz, H.A. and Yusoff, M.S. (2010) Trends in the Use of Fenton, Electro-Fenton and Photo-Fenton for the Treatment of Landfill Leachate. Waste Management, 30, 2113-2121. https://doi.org/10.1016/j.wasman.2010.07.003

  9. 9. Wiszniowski, J., Robert, D., Surmacz-Gorska, J., Miksch, K. and Weber, J.V. (2006) Landfill Leachate Treatment Methods: A Review. Environmental Chemistry Letters, 4, 51-61. https://doi.org/10.1007/s10311-005-0016-z

  10. 10. Carriazo, J.G., Moreno-Forero, M., Molina, R.A. and Moreno, S. (2010) Incorporation of Titanium and Titanium-Iron Species inside a Smectite-Type Mineral for Photocatalysis. Applied Clay Science, 50, 401-408. https://doi.org/10.1016/j.clay.2010.09.007

  11. 11. Morais, J.L. and Zamora, P.P. (2005) Use of Advanced Oxidation Processes to Improve the Biodegradability of Mature Landfill Leachates. Journal of Hazardous Materials, 123, 181-186. https://doi.org/10.1016/j.jhazmat.2005.03.041

  12. 12. Anglada, A., Urtiaga, A. and Ortiz, I. (2009) Pilot Scale Performance of the Electro-Oxidation of Landfill Leachate at Boron-Doped Diamond Anodes. Environmental Science & Technology, 43, 2035-2040. https://doi.org/10.1021/es802748c

  13. 13. Fernandes, A., Spranger, P., Fonseca, A.D., Pacheco, M.J., Ciríaco, L. and López, A. (2014) Effect of Electrochemical Treatment on the Biodegradability of Sanitary Landfill Leachates. Applied Catalysis B: Environmental, 144, 514-520. https://doi.org/10.1016/j.apcatb.2013.07.054

  14. 14. APHA (2012) Standard Methods for the Examination of Water and Wastewater, 22nd Edition. American Public Health Association/American Water Works Association/Water Environment Federation, Washington DC.

  15. 15. Foo, K.Y. and Hameed, B.H. (2009) An Overview of Landfill Leachate Treatment via Activated Carbon Adsorption Process. Journal of Hazardous Materials, 171, 54-60. https://doi.org/10.1016/j.jhazmat.2009.06.038

  16. 16. Turro, E., Giannis, A., Cossu, R., Gidarakos, E., Mantzavinos, D. and Katsaounis, A. (2012) Reprint of: Electrochemical Oxidation of Stabilized Landfill Leachate on DSA Electrodes. Journal of Hazardous Materials, 207, 73-78. https://doi.org/10.1016/j.jhazmat.2012.01.083

  17. 17. Papastavrou, C., Mantzavinos, D. and Diamadopoulos, E. (2009) A Comparative Treatment of Stabilized Landfill Leachate: Coagulation and Activated Carbon Adsorption vs. Electrochemical Oxidation. Environmental Technology, 30, 1547-1553. https://doi.org/10.1080/09593330903252240

  18. 18. Norma, D., Fernandes, A., Pacheco, M.J., Ciríaco, L. and Lopes, A. (2012) Electrocoagulation and Anodic Oxidation Integrated Process to Treat Leachate from a Portuguese Sanitary Landfill. Portugaliae Electrochimica Acta, 30, 221-234. https://doi.org/10.4152/pea.201203221

  19. 19. Ukundimana, Z., Omwene, P.I., Gengec, E.R.H.A.N., Can, O.T. and Kobya, M. (2018) Electrooxidation as Post Treatment of Ultrafiltration Effluent in a Landfill Leachate MBR Treatment Plant: Effects of BDD, Pt and DSA Anode Types. Electrochimica Acta, 286, 252-263. https://doi.org/10.1016/j.electacta.2018.08.019

  20. 20. Feki, F., Aloui, F., Feki, M. and Sayadi, S. (2009) Electrochemical Oxidation Post-Treatment of Landfill Leachates Treated with Membrane Bioreactor. Chemosphere, 75, 256-260. https://doi.org/10.1016/j.chemosphere.2008.12.013

  21. 21. Yousssef, S., Lamia, A. and Ridha, A. (2010) Electrochemical Degradation of Chlorpyrifos Pesticide in Aqueous Solutions by Anodic Axidation at Boron-Doped Diamond Electrodes. Chemical Engineering Journal, 161, 167-172. https://doi.org/10.1016/j.cej.2010.04.060

  22. 22. Chiang, L.C., Chang, J.E. and Wen, T.C. (1995) Indirect Oxidation Effect in Electrochemical Oxidation Treatment of Landfill Leachate. Water Research, 29, 671-678. https://doi.org/10.1016/0043-1354(94)00146-X

  23. 23. Méndez, R.I., Castillo, E.R., Sauri, M.R., Quintal, C.A., Giácoman, G. and Jímenez, B. (2009) Comparación de cuatro tratamientos fisicoquímicos de lixiviados. Revista internacional de contaminación ambiental, 25, 133-145.

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