Electrocoagulation and Coupled Processes for Urea Wastewater Removal: Parametric study and gradient boosting optimization.

Atba, Wafa; Cherifi, Mouna; Hazourli, Sabir; Boulmaiz, Amel; Lapicque, François; Grid, Azzeddine; Laefer, Debra F.

doi:10.2478/pjct-2025-0018

Abstract

This study investigates urea removal from wastewater using zinc-based electrocoagulation method, supported by Gradient Boosting Regressor modeling. The highest urea removal of 42% was obtained for 1.2 g/L initial urea concentration, 22 mA/cm² current density, and a pH solution of 10, while natural pH (≈7.50) gave 30%. By applying the optimum conditions 27% of urea was removed from real hospital effluent. Application of GBR model leveraging Artificial Intelligence (AI) demonstrated a high predictive accuracy (R² = 0.9825, RMSE = 0.01666) with experimental results. Treatment combination processes were investigated: Chemical Coagulation–Electrocoagulation achieved 35% efficiency, while two EC cycles yielded 45%. Electrocoagulated sludge characterization by scanning electron microscope/energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction analysis revealed surface irregularities as well as the presence of zinc, carbon, nitrogen, and sodium. These findings confirm the treatment’s effectiveness in removing urea and support the safe valorization and reuse of the sludge. EC proves effective and cost-efficient for industrial-scale implementation.

References

Urbańczyk, E., Sowa, M. & Simka, W. (2016). Urea removal from aqueous solutions—a review. J. Appl. Electrochem. 46(10),1011–1029. DOI: 10.1007/s10800-016-0993-6.
Search in Google Scholar Back to article
Weerakoon, D., Bansal, B. & Padhye, L.P. (2023). A critical review on current urea removal technologies from water: An approach for pollution prevention and resource recovery. Sep. Purif. Technol. 314 (February), 123652. DOI:10.1016/j.seppur.2023.123652.
Search in Google Scholar Back to article
El Gheriany, I., Abdel-Aziz, M.H., El-Ashtoukhy, E.S.Z. & Sedahmed, G.H. (2022) Electrochemical removal of urea from wastewater by anodic oxidation using a new cell design: An experimental and modeling study. Process Saf. Environ Prot. 159,133–145. DOI: 10.1016/j.psep.2021.12.055.
Search in Google Scholar Back to article
Shaban, A., Basiouny, M.E. & AboSiada, O.A.(2023). Evaluation of Using Sequential Electrocoagulation and Chemical Coagulation for Urea Removal from Synthetic and Domestic Wastewater. Water, Air, Soil Pollut. 234(11).1–14. DOI: 10.1007/s11270-023-06743-5.
Search in Google Scholar Back to article
Mamdouh, M., Safwat, S.M., Abd-Elhalim, H. & Rozaik,. E. (2021). Urea removal using electrocoagulation process with copper and iron electrodes. Desalin Water Treat. 213, 259–268. DOI: 10.5004/dwt.2021.26690.
Search in Google Scholar Back to article
Chen, Y., Chen, H., Chen, Z., Hu, H., Deng, C. & Wang, X.(2021). The benefits of autotrophic nitrogen removal from high concentration of urea wastewater through a process of urea hydrolysis and partial nitritation in sequencing batch reactor. J. Environ. Manage. 292(May),112762. DOI:10.1016/j.jenvman.2021.112762.
Search in Google Scholar Back to article
Safwat, S.M. & Matta, M.E.(2020). Performance evaluation of electrocoagulation process using zinc electrodes for removal of urea. Sep. Sci. Technol. 55(14), 2500–2509. DOI: 10.1080/01496395.2019.1636067.
Search in Google Scholar Back to article
Kameda, T., Horikoshi, K., Kumagai, S., Saito, Y. & Yoshioka, T. (2020). Adsorption of urea, creatinine, and uric acid onto spherical activated carbon. Sep. Purif. Technol. 237,116367. DOI: 10.1016/j.seppur.2019.116367.
Search in Google Scholar Back to article
Mahalik, K., Sahu, J.N., Patwardhan, A.V. & Meikap, B.C. (2010). Kinetic studies on hydrolysis of urea in a semi-batch reactor at atmospheric pressure for safe use of ammonia in a power plant for flue gas conditioning. J. Hazard Mater. 175(1–3), 629–637. DOI: 10.1016/j.jhazmat.2009.10.053.
Search in Google Scholar Back to article
Shen, S., Li, M., Li, B. & Zhao, Z. (2014).Catalytic hydrolysis of urea from wastewater using different aluminas by a fixed bed reactor. Environ. Sci. Pollut. Res. 21(21), 12563–12568. DOI: 10.1007/s11356-014-3189-9.
Search in Google Scholar Back to article
Tan, T., Liu, S., Chen, K., Imhanria, S., Tao, P. & Wang, W. (2020). A multi-component system for urea electrooxidation: Ir3Sn nanoparticles loading on Iron- and Nitrogen- codoped composite carbon support. J. Taiwan Inst. Chem. Eng. 112, 116–121. DOI: 10.1016/j.jtice.2020.06.017.
Search in Google Scholar Back to article
Von Ahnen, M., Pedersen, L.F., Pedersen, P.B. & Dalsgaard, J. (2015). Degradation of urea, ammonia and nitrite in moving bed biofilters operated at different feed loadings. Aquac Eng. 69, 50–59. DOI:10.1016/j.aquaeng.2015.10.004.
Search in Google Scholar Back to article
Lu, J., Zhang, P. & Li, J.(2024). Mo(VI) removal from water by aluminum electrocoagulation: Cost-effectiveness analysis, main influencing factors, and proposed mechanisms. J. Hazard Mater. 461 (June 2023), 132608. DOI: 10.1016/j.jhazmat.2023.132608.
Search in Google Scholar Back to article
Pinedo-Hernández, J., Marrugo-Negrete, J., Pérez-Espitia, M., Durango-Hernández, J., Enamorado-Montes, G. & Navarro-Frómeta, A.(2024). A pilot-scale electrocoagulation-treatment wetland system for the treatment of landfill leachate. J. Environ Manage. 351(December 2023). DOI: 10.1016/j.jenvman.2023.119681.
Search in Google Scholar Back to article
Rangseesuriyachai, T., Pinpatthanapong, K., Boonnorat, J., Jitpinit, S., Pinpatthanapong, T. & Mueansichai, T. (2024). Optimization of COD and TDS removal from high-strength hospital wastewater by electrocoagulation using aluminium and iron electrodes: Insights from central composite design. J. Environ. Chem. Eng. 12(1),111627. DOI: 10.1016/j.jece.2023.111627.
Search in Google Scholar Back to article
Sivaranjani., G.A. & Ali, N. (2020). Applicability and new trends of different electrode materials and its combinations in electro coagulation process: A brief review. Mater. Today Proc. 37 (Part 2), 377–382. DOI: 10.1016/j.matpr.2020.05.379.
Search in Google Scholar Back to article
Cherifi, M., Belkacem, M., Hazourli, S., Debra, F.L. & Atba, W. (2023). A comparative study of hydrogen peroxide oxidation and electrocoagulation using aluminum, iron, and zinc electrodes for urban sludge disintegration. Sep. Sci. Technol. 58(10),1806–1820. DOI: 10.1080/01496395.2023.2213395.
Search in Google Scholar Back to article
Hashim, K.S., Shaw, A., Al Khaddar, R., Pedrola, M.O. & Phipps, D. (2017). Iron removal, energy consumption and operating cost of electrocoagulation of drinking water using a new flow column reactor. J. Environ. Manage. 189, 98–108. DOI: 10.1016/J.JENVMAN.2016.12.035.
Search in Google Scholar Back to article
Ali, I., Asim, M. & Khan, TA. (2013). Arsenite removal from water by electro-coagulation on zinc-zinc and copper-copper electrodes. Int. J. Environ. Sci. Technol. 10(2), 377–384. DOI: 10.1007/s13762-012-0113-z.
Search in Google Scholar Back to article
Fajardo, A.S., Rodrigues, R.F., Martins, R.C., Castro, L.M. & Quinta-Ferreira, R.M.(2015). Phenolic wastewaters treatment by electrocoagulation process using Zn anode. Chem. Eng J. 275, 331–341. DOI:10.1016/J.CEJ.2015.03.116.
Search in Google Scholar Back to article
Gong, C., Zhang, J., Ren, X., He, C., Han, J. & Zhang, Z. (2022). A comparative study of electrocoagulation treatment with iron, aluminum and zinc electrodes for selenium removal from flour production wastewater. Chemosphere. 303(P3), 135249. DOI:10.1016/j.chemosphere.2022.135249.
Search in Google Scholar Back to article
Hussin, F., Abnisa, F., Issabayeva, G. & Aroua, MK.(2017). Removal of lead by solar-photovoltaic electrocoagulation using novel perforated zinc electrode. J. Clean Prod. 147, 206–216. DOI: 10.1016/j.jclepro.2017.01.096.
Search in Google Scholar Back to article
Safwat, S.M., Mamdouh, M., Rozaik, E. & Abd-Elhalim, H. (2020). Performance evaluation of electrocoagulation process using aluminum and titanium electrodes for removal of urea. Desalin Water Treat. 191, 239–249. DOI: 10.5004/dwt.2020.25616.
Search in Google Scholar Back to article
Obi, C.C., Nwabanne, J.T., Igwegbe, C.A., Ohale, P.E. & Okpala, COR. (2022). Multi-characteristic optimization and modeling analysis of electrocoagulation treatment of abattoir wastewater using iron electrode pairs. J. Water Process Eng. 49 (June),103136. DOI: 10.1016/j.jwpe.2022.103136.
Search in Google Scholar Back to article
Gholami Shirkoohi, M., Tyagi, R.D., Vanrolleghem, P.A. & Drogui, P. (2022). A comparison of artificial intelligence models for predicting phosphate removal efficiency from wastewater using the electrocoagulation process. Digit Chem. Eng. 4(June), 100043. DOI: 10.1016/j.dche.2022.100043.
Search in Google Scholar Back to article
Onu, C.E., Nweke, C.N. & Nwabanne, J.T. (2022). Modeling of thermo-chemical pretreatment of yam peel substrate for biogas energy production: RSM, ANN, and ANFIS comparative approach. Appl. Surf. Sci. Adv. 11(April), 100299. DOI: 10.1016/j.apsadv.2022.100299.
Search in Google Scholar Back to article
Igwegbe, C.A., Obi, C.C. & Ohale, P.E. (2023). Modelling and optimisation of electrocoagulation/flocculation recovery of effluent from land-based aquaculture by artificial intelligence (AI) approaches. Environ Sci. Pollut. Res. 30(27), 70897–70917. DOI: 10.1007/s11356-023-27387-2.
Search in Google Scholar Back to article
Wang, G., Jia, Q.S., Zhou, M.C., Bi, J., Qiao, J. & Abusorrah, A. (2022). Artificial neural networks for water quality soft-sensing in wastewater treatment: a review. Artif. Intell. Rev. 55(1), 565–587. DOI: 10.1007/s10462-021-10038-8.
Search in Google Scholar Back to article
Touzani, S., Granderson, J. & Fernandes, S. (2018). Gradient boosting machine for modeling the energy consumption of commercial buildings. Energy Build. 158, 1533–1543. DOI: 10.1016/j.enbuild.2017.11.039.
Search in Google Scholar Back to article
Boulmaiz, A., Berredjem, H., Cheikchouk, K., Boulkrah, A., Aouras, H. & Djedi, H. (2024). Predicting HER2 Status Associated with Breast Cancer Aggressiveness Using Four Machine Learning Models. Asian Pacific J. Cancer Prev. 25(10), 3609–3618. DOI: 10.31557/APJCP.2024.25.10.3609.
Search in Google Scholar Back to article
Obi, C.C., Nwabanne, J.T., Igwegbe, C.A., Abonyi, M.N., Umembamalu, C.J. & Kamuche, T.T.G. (2024). Intelligent algorithms-aided modeling and optimization of the deturbidization of abattoir wastewater by electrocoagulation using aluminium electrodes. J. Environ. Manage. 353 (November 2023),120161. DOI: 10.1016/j.jenvman.2024.120161.
Search in Google Scholar Back to article
Otchere, D.A., Ganat, T.O.A., Ojero, J.O., Tackie-Otoo, B.N. & Taki, M.Y. (2022). Application of gradient boosting regression model for the evaluation of feature selection techniques in improving reservoir characterisation predictions. J. Pet. Sci. Eng. 208(May),109244. DOI: 10.1016/j.petrol.2021.109244.
Search in Google Scholar Back to article
Wang, H. & Gu, G. (2015). Wavelet gradient boosting regression method study in short-term load forecasting. Smart Grid. 5(4), 189–196. DOI: 10.12677/sg.2015.54023.
Search in Google Scholar Back to article
Fox, J. & Weisberg, S. (2018). An R Companion to Applied Regression. Sage publications.
Search in Google Scholar Back to article
Chan, K.M.A., Boyd, D.R. & Gould, R.K.(2020). Levers and leverage points for pathways to sustainability. People Nat. 2(3), 693–717. DOI: 10.1002/pan3.10124.
Search in Google Scholar Back to article
Bajpai, M., Katoch, S.S., Kadier, A. & Singh, A. (2022). A review on electrocoagulation process for the removal of emerging contaminants: theory, fundamentals, and applications. Environ. Sci. Pollut. Res. 29(11), 15252–15281. DOI: 10.1007/s11356-021-18348-8.
Search in Google Scholar Back to article
Asaithambi, P. (2016). Studies on various operating parameters for the removal of COD from pulp and paper industry using electrocoagulation process. Desalin Water Treat. 57(25), 11746–11755. DOI: 10.1080/19443994.2015.1046149.
Search in Google Scholar Back to article
Jing, G., Ren, S., Pooley, S., Sun, W., Kowalczuk, P.B. & Gao, Z. (2021). Electrocoagulation for industrial wastewater treatment: an updated review. Environ. Sci. Water Res. Technol. 7(7), 1177–1196. DOI: 10.1039/D1EW00158B.
Search in Google Scholar Back to article
El-Shazly, A.H. & Daous, M.A. (2013). Kinetics and performance of phosphate removal from hot industrial effluents using a continuous flow electrocoagulation reactor. Int. J. Electrochem. Sci. 8(1),184–194. DOI: 10.1016/s1452-3981(23)14012-0.
Search in Google Scholar Back to article
Khanaum, M.M. & Borhan, M.S. (2023). Electrocoagulation: An Overview of the Technology for Livestock Farm Wastewater Treatment. Waste Technol. 11(1), 1–16. DOI: 10.14710/wastech.11.1.1-16.
Search in Google Scholar Back to article
Bener, S., Bulca, Ö., Palas, B., Tekin, G., Atalay, S. & Ersöz, G. (2019). Electrocoagulation process for the treatment of real textile wastewater: Effect of operative conditions on the organic carbon removal and kinetic study. Process Saf. Environ. Prot. 129, 47–54. DOI: 10.1016/j.psep.2019.06.010.
Search in Google Scholar Back to article
Simka, W., Piotrowski, J. & Nawrat, G.(2007). Influence of anode material on electrochemical decomposition of urea. Electrochim Acta. 52(18), 5696–5703. DOI:10.1016/j.electacta.2006.12.017.
Search in Google Scholar Back to article
Simka, W., Piotrowski, J., Robak, A. & Nawrat, G. (2009). Electrochemical treatment of aqueous solutions containing urea. J. Appl. Electrochem. 39(7), 1137–1143. DOI: 10.1007/s10800-008-9771-4.
Search in Google Scholar Back to article
Hakizimana, J.N., Gourich, B. & Chafi, M. (2017). Electrocoagulation process in water treatment: A review of electrocoagulation modeling approaches. Desalination. 404, 1–21. DOI: 10.1016/j.desal.2016.10.011.
Search in Google Scholar Back to article
Atba, W., Cherifi, M., Grid, A., Debra, F.L. & Hazourli, S. (2023). Effect of Electrocoagulation Parameters on Chromium Removal, Sludge Settling, and Energy Consumption. Anal. Bioanal. Electrochem. 15(3), 166–183. DOI: 10.22034/abec.2023.703899.
Search in Google Scholar Back to article
Shaker, O.A., Safwat, S.M. & Matta, M.E. (2023). Nickel removal from wastewater using electrocoagulation process with zinc electrodes under various operating conditions: performance investigation, mechanism exploration, and cost analysis. Environ. Sci. Pollut. Res. 30(10), 26650–26662. DOI: 10.1007/s11356-022-24101-6.
Search in Google Scholar Back to article
Arroyo, M.G., Pérez-Herranz, V., Montañés, M.T., García-Antón, J. & Guiñón, J.L. (2009). Effect of pH and chloride concentration on the removal of hexavalent chromium in a batch electrocoagulation reactor. J. Hazard. Mater. 169(1-3), 1127–1133. DOI: 10.1016/j.jhazmat.2009.04.089.
Search in Google Scholar Back to article
Chen, G., Chen, X. & Yue, PL. (2000). E Lectrocoagulation and E Lectroflotation. J Environ Eng. 126(September), 858–863.
Search in Google Scholar Back to article
Uhlig, H.H. & Revie, R.W. (2000). Uhlig’s Corrosion Handbook.
Search in Google Scholar Back to article
Comninellis, C. & Chen, G. (2010). Electrochemistry for the Environment. 2015.
Search in Google Scholar Back to article
Graça, N.S., Ribeiro, A.M. & Rodrigues, A.E. (2019). Modeling the electrocoagulation process for the treatment of contaminated water. Chem. Eng. Sci. 197, 379–385. DOI: 10.1016/j.ces.2018.12.038.
Search in Google Scholar Back to article
Tiaiba, M., Merzouk, B., Amour, A., Mazour, M., Leclerc, J.P. & Lapicque, F. (2017). Influence of electrodes connection mode and type of current in electrocoagulation process on the removal of a textile dye. Desalin Water Treat. 73, 330–338. DOI: 10.5004/DWT.2017.20502.
Search in Google Scholar Back to article
Safwat, S.M. (2020). Treatment of real printing waste-water using electrocoagulation process with titanium and zinc electrodes. J. Water Process Eng. 34(January), 101137. DOI: 10.1016/j.jwpe.2020.101137.
Search in Google Scholar Back to article
Safwat, S.M., Hamed, A. & Rozaik, E. (2019). Electrocoagulation/electroflotation of real printing wastewater using copper electrodes: A comparative study with aluminum electrodes. Sep. Sci. Technol. 54(1),183–194. DOI: 10.1080/01496395.2018.1494744.
Search in Google Scholar Back to article
Medina Collana, J.T., Ayllon Ormeño, M. & Julca Meza, C. Processes Coupled to Electrocoagulation for the Treatment of Distillery Wastewaters. Sustain. 16(15). DOI: 10.3390/su16156383.
Search in Google Scholar Back to article
Al-Kilani, M.R. & Bani-Melhem, K. (2025). The performance of electrocoagulation process for decolorization and COD removal of highly colored real grey water under variable operating conditions. Desalin Water Treat. 321 (November 2024), 100924. DOI: 10.1016/j.dwt.2024.100924.
Search in Google Scholar Back to article
Al-Raad, A.A. & Hanafiah, M.M. (2021). Removal of inorganic pollutants using electrocoagulation technology: A review of emerging applications and mechanisms. J. Environ Manage. 300 (February), 113696. DOI: 10.1016/j.jenvman.2021.113696.
Search in Google Scholar Back to article
Attour, A., Touati, M., Tlili, M., Ben Amor, M., Lapicque, F. & Leclerc, JP.(2014). Influence of operating parameters on phosphate removal from water by electrocoagulation using aluminum electrodes. Sep. Purif. Technol. 123, 124–129. DOI: 10.1016/j.seppur.2013.12.030.
Search in Google Scholar Back to article
Vasudevan, S., Lakshmi, J. & Sozhan, G. (2012). Toxicological & Environmental Chemistry Simultaneous removal of Co, Cu, and Cr from water by electrocoagulation. Toxicol Environ. Chem. 94 (December 2012), 37–41.
Search in Google Scholar Back to article
Vepsäläinen, M., Ghiasvand, M. & Selin, J. (2009). Investigations of the effects of temperature and initial sample pH on natural organic matter (NOM) removal with electro-coagulation using response surface method (RSM). Sep. Purif. Technol. 69(3), 255–261. DOI: 10.1016/j.seppur.2009.08.001.
Search in Google Scholar Back to article
Song, S., He, Z., Qiu, J., Xu, L. & Chen, J. (2007). Ozone assisted electrocoagulation for decolorization of C.I. Reactive Black 5 in aqueous solution: An investigation of the effect of operational parameters. Sep. Purif. Technol. 55(2), 238–245. DOI: 10.1016/j.seppur.2006.12.013.
Search in Google Scholar Back to article
El-Naas, M.H., Al-Zuhair, S., Al-Lobaney, A. & Makhlouf, S. (2009). Assessment of electrocoagulation for the treatment of petroleum refinery wastewater. J. Environ. Manage. 91(1), 180–185. DOI: 10.1016/j.jenvman.2009.08.003.
Search in Google Scholar Back to article
Khandegar, V. & Saroha, A.K. (2013). Electrocoagulation for the treatment of textile industry effluent - A review. J. Environ. Manage. 128, 949–963. DOI: 10.1016/j.jenvman.2013.06.043.
Search in Google Scholar Back to article
Shaban, A., Basiouny, M.E. & AboSiada, O.A. (2024). Comparative study of the removal of urea by electrocoagulation and electrocoagulation combined with chemical coagulation in aqueous effluents. Sci. Rep. 14(1), 1–14. DOI: 10.1038/s41598-024-81422-x.
Search in Google Scholar Back to article
Hassan, K., Farzana, R. & Sahajwalla, V. (2019). In-situ fabrication of ZnO thin film electrode using spent Zn–C battery and its electrochemical performance for supercapacitance. SN Appl. Sci. 1(4),1–13. DOI: 10.1007/s42452-019-0302-1.
Search in Google Scholar Back to article
Medvidović, N.V., Vrsalović, L., Svilović, S., Bilušić, A. & Jozić, D. (2023). Electrocoagulation treatment of compost leachate using aluminium alloy, carbon steel and zinc anode. Appl. Surf. Sci. Adv. 15 (December 2022). DOI: 10.1016/j.apsadv.2023.100404.
Search in Google Scholar Back to article
Kuchar, D., Fukuta, T., Onyango, M.S. & Matsuda, H. (2006). Sulfidation of zinc plating sludge with Na2S for zinc resource recovery. J. Hazard. Mater. 137(1), 185–191. DOI: 10.1016/j.jhazmat.2006.01.052.
Search in Google Scholar Back to article
Xu, Z., Ma, X., Liao, J., Osman, S.M., Wu, S. & Luque, R. (2022). Effects on the Physicochemical Properties of Hydrochar Originating from Deep Eutectic Solvent (Urea and ZnCl₂)-Assisted Hydrothermal Carbonization of Sewage Sludge. ACS Sustain. Chem. Eng. 10(13), 4258–4268. DOI: 10.1021/acssuschemeng.2c00086.
Search in Google Scholar Back to article
Nguyen, M.D., Thomas, M., Surapaneni, A., Moon, E.M. & Milne, N.A. (2022). Beneficial reuse of water treatment sludge in the context of circular economy. Environ. Technol. Innov. 28, 102651. DOI: 10.1016/j.eti.2022.102651.
Search in Google Scholar Back to article
Rodriguez, N., Gijsemans, L. & Bussé, J. (2020). Selective Removal of Zinc from BOF Sludge by Leaching with Mixtures of Ammonia and Ammonium Carbonate. J. Sustain Metall. 6(4), 680–690. DOI: 10.1007/s40831-020-00305-3.
Search in Google Scholar Back to article
Liu, S.H. & Wang, H.P. (2008). Fate of zinc in an electro-plating sludge during electrokinetic treatments. Chemosphere. 72(11), 1734–1738. DOI: 10.1016/j.chemosphere.2008.04.077.
Search in Google Scholar Back to article
Hegazy, B.E. (2007). Brick making from water treatment plant sludge. J. Eng. Appl. Sci. 54(6), 599–615.
Search in Google Scholar Back to article

Electrocoagulation and Coupled Processes for Urea Wastewater Removal: Parametric study and gradient boosting optimization.

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