Combining Effluent Treatment Methods to Remove Ammonia Nitrogen from Tannery Wastewater

Abstract

This study assessed the removal efficiency of ammonia nitrogen from tannery wastewater by combining electrocoagulation, ozonation, and ion exchange technologies. For this purpose, an electrocoagulation reactor equipped with aluminum electrodes, an ozonation tank, and a filtration system with zeolite were employed. The electrocoagulation treatment applied the response surface methodology with a 3k factorial design with the following two factors: current intensity (I) ranging from 3 to 7A, and treatment time (t) from 10 to 30 min; the removal percentage of total suspended solids (TSS) is set as a response variable. Results indicate that the treatment time and current intensity were significant for the removal of total suspended solids TSS, at a confidence level of p < 0,05. Under these conditions, a TSS, removal efficiency of 98% was achieved. Through the electrocoagulation process, the chemical oxygen demand (COD) was reduced by 58%, while in the ozonation tank, an additional 23% of COD was removed. The filtration stage demonstrated that 13X HP zeolite can exchange ions with the ammonia nitrogen from tannery wastewater, wherein a 39% removal efficiency is reached at equilibrium. Thus, the integration of various treatment methods is a viable alternative to reduce wastewater from the tannery industry. The novelty of this research lies in the integration of three methods for treating tannery wastewater. The results show that the combination of these treatments provides a more effective solution for removing the pollutant load, especially nitrogen, compared to the use of individual treatment methods alone. The study opens new perspectives for optimizing multi-stage treatment processes. © 2025 Elsevier B.V., All rights reserved.