In this study, a combined system integrating an ozonation reactor and electrocoagulation (EC) reactor
was investigated to remove C.I Acid Red 114 (AR 114) dye in the synthetic dyeing wastewater. The
separated EC and ozonation systems were performed as control experiments as well. Hydraulic
retention time (HRT) of each system was determined. These systems were operated with 100 mg/L
AR 114 dye wastewater at determined optimal conditions. The results showed that colour, dye and
CODcr were highly removed by the combined system with only the HRT of 2 min in the ozonation
reactor and 0.85 min in the EC reactor. Their average efficiencies were archived up to 93%, 94.25%
and 80.6%, respectively. In addition, the energy consumption, volume and mass of waste sludge were
evaluated to be low (0.4 kWh/m3, 30 L/m3 and 77 g/m3). When compared between the combined system
and the control systems based on the same decolorization performance, the results indicated that the
combined system has shorter HRT, less energy consumption than others and less waste sludge
generation than the separated EC system.