Abstract

The present study aimed to evaluate the treatment performance of centralized industrial wastewater using the activated sludge (AS) process combined with powdered activated carbon (PAC) and poly aluminum chloride (PACl). The experiment with PAC was tested at five concentrations of 0.0, 0.5, 1.0, 2.0, and 4.0 g PAC/L_sludge, while a PACl was applied at 0, 20, 40, 80, and 160 mg Al/L_sludge for 120 minutes. With a C/C₀ ratio of less than 1.0, the addition of PAC and PACl significantly improved the treatment efficiency. Accordingly, the concentrations of COD and NH₄⁺-N at the end of the experiment were lower than the initial values in both PAC and PACl experiments. For COD, PACl showed a higher reduction than PAC, with C/C₀ ranging from 0.2 to 0.8, whereas PAC reached only 0.7 to 0.9. Similarly, NH₄⁺-N concentrations also decreased after 120 minutes, with C/C₀ ranging from 0.7 to 0.8 in both experiments. Furthermore, the treatment efficiency showed a tendency to increase with increasing dosages of PAC and PACl. The study provides a broader perspective on enhancing the treatment efficiency of industrial wastewater through the combination of adsorption or chemical coagulants processes with the AS process. Data from the investigated PAC and PACl dosages help determine their effective operating ranges in centralized industrial wastewater, thereby supporting the selection of appropriate operational conditions that ensure both technical and economic efficiency while avoiding waste of materials and chemicals.