Which treatment procedure among electrocoagulation, biological, adsorption, and bio-adsorption processes performs best in azo dyes removal?

Abstract

For decades, “Which treatment process is the best?” has been the primary question for many researchers worldwide. Therefore, this study aims to optimize the treatment models using the Imperialist Competitive Algorithm (ICA) to achieve a techno-economical comparison of biological, adsorption, electrocoagulation (EC), and bio-adsorption processes as examples in Acid Orange 7 (AO 7) and Acid Red 18 (AR 18) removal. Membrane Sequencing Batch Reactor (MSBR), Granular Activated Carbon (GAC), and GAC-MSBR were selected as biological, adsorbent, and biological-adsorption processes, respectively. MSBR was the cheapest (0.02–0.08 US$/m3) followed by GAC (0.03–0.63 US$/m3). Although MSBR permeates may not be of desirable quality, GAC and GAC-MSBR permeate offer the best quality. In addition to high operating costs in EC (≥1 US$/m3), the electrodes should be changed after several usages, which cost approximately 550 US$/m3. In this research, GAC-MSBR, as an effective process, had 80–100% AR 18 removal efficiency (0.14–0.16 US$/m3).

Keywords

• Acid orange 7 (AO 7)
• Acid red 18 (AR 18)
• Activated carbon
• Adsorption
• Electrocoagulation
• Membrane bioreactor (MBR)