Available online 28 December 2023 0022-2860/© 2023 Published by Elsevier B.V. Investigation of the removal of color and heavy metal from wastewater using activated sludge continuous system and application of models

In the continuous system studies, the natural state of the activated sludge was used in the fixed bed column and fluidized bed column, and the studies were carried out with the synthetic solution wastewater similar to the metal coating industry. Experiments at operating conditions of bed heights 20 cm, initial Cu2+, Ni2+, and Methylene Blue concentrations of 100 mg/L, pH 5.0 and flow rates 2 mL/min were performed to study the performance of the fixed bed column and fluidized bed column. It is seen that the removal efficiencies of the fixed bed and fluidized bed column are very close to each other. Thomas, Yoon-Nelson and Bohart-Adams models were applied to the data obtained in the fixed bed column system. It has been observed that there is a good agreement between the experimental breakthrough curves and the model predictions. In addition, regeneration of activated sludge with 0.1 M HCl and a reuse experiments were carried out, and it was observed that the efficiency decreased considerably in the second use. The results are promising and shall serve to design the activated sludge based fixed bed column and fluidized bed column to obtain cleaner and sustainable treatment of industrial wastewaters containing Cu, Ni and Methylene Blue.