Effect of an Electromagnetic Field on Anaerobic Digestion: Comparing an Electromagnetic System (ES), a Microbial Electrolysis System (MEC), and a Control with No External Force

Nhlanganiso Ivan Madondo; Emmanuel Kweinor Tetteh; Sudesh Rathilal; Babatunde Femi Bakare

doi:10.3390/molecules27113372

Molecules (May 2022)

Effect of an Electromagnetic Field on Anaerobic Digestion: Comparing an Electromagnetic System (ES), a Microbial Electrolysis System (MEC), and a Control with No External Force

Nhlanganiso Ivan Madondo,
Emmanuel Kweinor Tetteh,
Sudesh Rathilal,
Babatunde Femi Bakare

Affiliations

Nhlanganiso Ivan Madondo: Green Engineering Research Group, Department of Chemical Engineering, Faculty of Engineering and The Built Environment, Steve Biko Campus, Durban University of Technology, S4 Level 1, Durban 4000, South Africa
Emmanuel Kweinor Tetteh: Green Engineering Research Group, Department of Chemical Engineering, Faculty of Engineering and The Built Environment, Steve Biko Campus, Durban University of Technology, S4 Level 1, Durban 4000, South Africa
Sudesh Rathilal: Green Engineering Research Group, Department of Chemical Engineering, Faculty of Engineering and The Built Environment, Steve Biko Campus, Durban University of Technology, S4 Level 1, Durban 4000, South Africa
Babatunde Femi Bakare: Department of Chemical Engineering, Faculty of Engineering, Mangosuthu University of Technology, P.O. Box 12363, Durban 4026, South Africa

DOI: https://doi.org/10.3390/molecules27113372
Journal volume & issue: Vol. 27, no. 11
p. 3372

Abstract

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This study examined the application of an electromagnetic field to anaerobic digestion by using an electromagnetic system (ES), a microbial electrolysis cell (MEC), and a control with no external force. The experimental work was performed by carrying out biochemical methane potential (BMP) tests using 1 L biodigesters. The bioelectrochemical digesters were supplied with 0.4 V for 30 days at 40 °C. The electromagnetic field of the ES was generated by coiling copper wire to form a solenoid in the BMP system, whereas the MEC consisted of zinc and copper electrodes inside the BMP system. The best performing system was the MEC, with a yield of 292.6 mL CH4/g chemical oxygen demand removed (CODremoved), methane content of 86%, a maximum current density of 23.3 mA/m2, a coulombic efficiency of 110.4%, and an electrical conductivity of 180 µS/cm. Above 75% removal of total suspended solids (TSS), total organic carbon (TOC), phosphate, and ammonia nitrogen (NH3-N) was also recorded. However, a longer exposure (>8 days) to higher magnetic intensity (6.24 mT) on the ES reduced its overall performance. In terms of energy, the MEC produced the greatest annual energy profit (327.0 ZAR/kWh or 23.36 USD/kWh). The application of an electromagnetic field in anaerobic digestion, especially a MEC, has the potential to maximize the methane production and the degradability of the wastewater organic content.

Published in Molecules

ISSN: 1420-3049 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Science: Chemistry: Organic chemistry
Website: http://www.mdpi.com/journal/molecules

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