An integrated constructed wetland-Microbial fuel cell system with sewage sludge-biochar to enhance treatment and energy recovery efficiencies

Fuhao ZHANG, Cheng SHEN, Yaqian ZHAO, Shaochen ZHANG, Yin WANG, Bin JI, Ranbin LIU, Ming Hung WONG, Shengdao SHAN, Jin ZHANG

Research output: Contribution to journalArticlespeer-review

Abstract

Constructed wetlands and microbial fuel cells (CW-MFCs) are a promising green and sustainable wastewater treatment technology. However, the power production performance of CW-MFCs has long been limited by low-performance cathodes. In this study, we designed two CW-MFC systems using cheap and readily available sewage sludge biochar (SSB) as the substrate for the experimental units. The integration of SSB significantly facilitated the removal of chemical oxygen demand, ammonium nitrogen, total nitrogen, and total phosphorus. Moreover, SSB enhanced the electrochemical performance of the air cathode, resulting in higher power density (44.64 mW/m2) and lower internal resistance (900.00 Ω) compared to gravel-integrated CW-MFC (0.88 mW/m2, 2057.14 Ω). In addition, a typical electroactive bacterium-Geobacter was enriched in the SSB-integrated CW-MFC system. The iron oxides and graphic nitrogen of the SSB favor the growth of Geobacter, and the redox-active groups on the surface of SSB accelerate the extracellular electron transfer process, contributing to the enhancement of treatment performance. Meanwhile, the metal and nitrogen doping improves the oxygen reduction reaction activity and conductivity of SSB, enhancing the cathode area of CW-MFC and improving the energy recovery. Overall, these results demonstrated that SSB-integrated CW-MFC can be a competitive technology for effective wastewater treatment and energy recovery. Copyright © 2024 Elsevier B.V. All rights reserved.

Original languageEnglish
Article number150431
JournalChemical Engineering Journal
Volume486
Early online dateMar 2024
DOIs
Publication statusPublished - Apr 2024

Citation

Zhang, F., Shen, C., Zhao, Y., Zhang, S., Wang, Y., Ji, B., Liu, R., Wong, M. H., Shan, S., & Zhang, J. (2024). An integrated constructed wetland-Microbial fuel cell system with sewage sludge-biochar to enhance treatment and energy recovery efficiencies. Chemical Engineering Journal, 486, Article 150431. https://doi.org/10.1016/j.cej.2024.150431

Keywords

  • Sewage sludge-biochar
  • Constructed wetland
  • Microbial fuel cell
  • Cathode
  • Energy recovery

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