Removal of arsenic from drinking water: A comparative study between electrocoagulation-microfiltration and chemical coagulation-microfiltration processes

• EC-MF and CC-MF processes are effective in removing As from water.
• The best performances were established using 4.0 mg Fe3+/L and pH 7.0.
• As concentration (C0 = 100 μg/L) could be optimally diminished by up to 97%.
• CC-MF was more effective than EC-MF in terms of cost-effectiveness.
• CC-MF involved a total cost of USD$ 0.066/m3 versus USD$ 0.12/m3 for EC-MF.

Experimental tests have been conducted to assess the effectiveness of a process combining electrocoagulation and microfiltration (EC-MF), which has been compared with a chemical coagulation coupled with microfiltration (CC-MF) for removal of arsenic (C0 = 100 μg/L) from drinking water. Different operating parameters such as iron concentration, reaction time, initial pH and degree of mixing inside the reactor were successively investigated. The best operating conditions (97% of As removal) were obtained at a pH of 7.0 and a concentration of 4.0 mg/L of Fe3+ using the CC-MF process. It took 26 h for the system to maintain a residual arsenic concentration below the limiting value (10 μg/L) recommended by the World Health Organization (WHO). The treatment cost using CC-MF system was evatuated to USD$ 0.066 per cubic meter of treated water. By comparison, a treatment cost of USD$ 0.12 per cubic meter of treated water was recorded using EC-MF system operated in the best operating conditions (inter-electrode gap of 0.4 cm, a concentration of 4 mg/L of Fe3+ produced by anodic dissolution by maintaining a pH around 7.0). The residual arsenic concentration was maintained below the limiting value recommended during a period of 16 h of continuous mode operation.