Electrocagulation Coupled With Carbon Fiber Filtration Enables Stable Performance and Low Sludge Production over a Broad Range of Operating Temperatures

As industrial wastewater discharges continue to increase, which is hazardous and stable, it is important to develop the treatment method that is highly effective and low operational cost. This study describes a reactor that comprises a sacrificial Fe anode and a novel carbon fiber filter cathode to combine electrocoagulation with contracted carbon fiber filter (EC–CCF). Such configuration can achieve the high removal efficiency under low current densities, thereby significantly reducing sludge production. The EC–CCF can achieve a removal efficiency of 96.7% using Acid Orange 7 (AO7) as the model pollutant at a low current density of 20 A m–2, which was 50% less than that of the EC reactor, thereby producing 55.1% less sludge. Additionally, the EC–CCF reactor maintained a stable performance over a range of operating temperatures from 25 to 5 °C, while the removal efficiency of the EC decreased from 83.9 to 54.2%. Electrochemical backwashing and pore size increase can achieve a 96% flux recovery, effectively removing both external and internal fouling of the EC–CCF. Meanwhile, the EC–CCF reactor achieved an effective removal efficiency using actual wastewater while maintaining a near full flux recovery over 20 cleaning cycles. The overall economic analysis revealed that EC–CCF offers high removal efficiency, performance stability, and cost effectiveness due to much lower operating current densities and sludge production. Therefore, EC–CCF is a promising technique that offers a stable performance and low overall cost for treating industrial wastewater.