Performance and mechanistic study on electrocoagulation process for municipal wastewater treatment based on horizontal bipolar electrodes

Highlights

• EC modified with BPEs enhances pollutant removal and reduce energy consumption.

• Increasing BPE number cannot increase flocculants yield exponentially.

• Simulations help to predict the distribution of electrochemical reactions on BPEs.

Abstract

The design of electrodes is crucial to electrocoagulation process (EC), specifically, with respect to pollutant removal and energy consumption. During EC, the mechanisms for interaction between different electrode arrangement and electrode reactions remain unclear. This work presents an integrated EC process based on horizontal bipolar electrodes (BPEs). In the electrochemical cell, the graphite plates are used as driving cathode while either Fe or Al plates serves as driving anode and BPEs. The BPEs are placed horizontally between the driving electrodes. For municipal wastewater treatment, the pollutant removal efficiency and energy consumption in different configurations of two-dimension electrocoagulation (2D-EC) system with horizontal BPEs were investigated. The removal efficiency of turbidity, total phosphorus and total organic carbon increased significantly with the number of BPEs. Noted that the energy consumption for TP removal decreased by 75.2% with Fe driving anode and 81.5% with Al driving anode than those of 2D-EC, respectively. In addition, the physical field simulation suggested the distributions of potential and current in electrolyte and that of induced charge density on BPE surface. This work provides a visual theoretical guidance to predict the distribution of reactions on BPEs for enhanced pollutant removal and energy saving based on electrocoagulation process for municipal wastewater treatment.

Graphical abstract

Keywords

Electrocoagulation / Bipolar electrodes / Municipal wastewater / Simulations

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Acknowledgements

Project supported by the National Natural Science Foundation of China (Grant Nos. 51822806, 51678184 and 51761145031), and Fundamental Research Funds for the Central Universities (Grant HIT.BRETIV.201905).

Electronic Supplementary Material

Supplementary material is available in the online version of this article at https://doi.org/10.1007/s11783-020-1215-3 and is accessible for authorized users.

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