Fixed-bed adsorption of tannery wastewater pollutants using bottom ash: An optimized process

This study investigates the reuse of bottom ash for the treatment of the tannery effluent in the fixed-bed column adsorption process. A parametric analysis of the process is carried out with conditions such as granulometry, adsorbent bed height and withdrawal flow rate, in order to evaluate optimal output and achieve optimum removal capacity of coloration. The results shows that, under 80 μm of granulometry, 15 mL.min−1 of flow rate and 11 cm of bed height, the discolouration rate reached maximum values close to 100%. Subsequently, we attempted to improve the quality of the final influent under controlled conditions through chain-continuous adsorption in a descending grain size system while measuring certain parameters such as electrical conductivity, pH, COD, absorbance, flow rate and volume at the outlet of each column. As a result, this technique allows for a reduction of 97.1% in COD. Finally, the Surface Response Method (RSM) is used to determine the main individual effects and to study the interaction of continuous adsorption process variables with a minimum number of experiments. Regression analysis with a 95% confidence level to confirm the significance of the model terms with a coefficient of determination (R2) of 0.9887 and a Fisher Value of 75.9.