Novel Multistage Electrochemical Flow-through Mode (EFTM) with Porous Electrodes for Reclaimed Wastewater Treatment in Pipes
Cong Zhang, Xin Zhao, Can Wang, Shuang Pan
Abstract
Removal of refractory organics and bacterial inactivation are the keys to ensuring the safety of reclaimed wastewater. Here, we proposed a new idea that reclaimed wastewater is treated using a novel, efficient, and energy-efficient multistage electrochemical flow-through mode (EFTM) as a segment of pipelines in a distribution system. The effects of voltage and flow velocity on the reclaimed wastewater treatment by using a three-stage EFTM were investigated. At a voltage of 5.0 V and a flow velocity of 0.20 cm·s–1, the chemical oxygen demand (COD) removal efficiency and bacterial inactivation reached 95.65% and 7 logs, respectively, after 30 min of electrolysis for the three-stage EFTM. The feasibility of the multistage EFTM for practical reclaimed wastewater treatment was validated by electrochemical test and energy consumption calculation. The practical reclaimed wastewater treated using the multistage EFTM in pipes required 236–377 pairs of electrodes (with a thickness of 10 cm) to achieve the goal that the COD removal efficiency was over 90%, the bacterial inactivation reached 8 logs, and EE/O was lower than 0.62 kWh·m–3. This finding suggested that the multistage EFTM showed great potential for engineering application and ensured the safety of water quality in a pipe network.