Continuous-flow electrocoagulation (EC) process for iron removal from water: Experimental, statistical and economic...

The process of Electrocoagulation (EC), the in-situ production of coagulants by passing an electric current through sacrificial electrodes, is free of chemical additives and cost-effective. This makes it the most widely used water and wastewater treatment method. However, the literature highlights some significant drawbacks of this method including EC unit design limitations. This research therefore aimed to develop a new EC unit design using drilled plates (electrodes) to mix the solution being treated without using external mixers, this minimising power consumption. The performance of the new EC unit was validated by applying it to remove iron from water taking into account the effects of applied current density (ACD), the pH of the water (PoW), iron concentration (IC) and treatment time (TT). The effects of these parameters were optimised using the Box-Behnken model. Synthetic water samples containing different concentrations of iron (10-30 mg/l), were treated in a continuous flow, using the new EC reactor at different ACD (1.5-4.5 mA/cm²), PoW (4-10) and TT (10-50 min). The results revealed that the removal of 99.9% of iron was achieved by keeping PoW, ACD, IC and TT at 7, 3 mA/cm², 10 mg/l and 50 min, respectively. The effects of ACD, POW, IC and TT on iron removal could be successfully simulated with R² = 0.9788. The cost of removing iron using the proposed EC unit was 0.623 £/m³.