Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
The effect of the external load on the performance of microbiological fuel cells for acid mine drainage remediation and energy generation
Submission Author:
Elise Watzko , SC
Co-Authors:
Elise Watzko, laryssa moraes , Julia Anselmo , Tatiana Pineda, REGINA ANTONIO, Lauber Martins, JOSÉ VIRIATO COELHO VARGAS
Presenter: Elise Watzko
doi://10.26678/ABCM.COBEM2021.COB2021-1591
Abstract
Microbial fuel cells (MFCs) are a new sustainable alternative for electric power generation and treatment of effluents. Such devices can convert several types of organic substrates directly into electricity. Acid mine drainage (AMD) is one of them. AMD is an environmental problem since it has bad effects on surface and subterranean waters due its low pH, high concentration of sulfates, toxic metals and dissolved salts. MFCs systems are complex and demand profound studies to determine the behavior and repeatability of their beneficial effects. The herein research presents experimental results of an external load connected to an MFC system for treatment of a synthetic AMD aiming to reduce the concentration of sulfates and to generate electric power. Eight MFCs of the type H were built using a proton exchange membrane (Nafion 117). The anodic chamber was inoculated with domestic wastewater sludge, the cathodic chamber was inoculated with sulfate-reducing bacteria (SRB) and the electrodes were made of Graphite cylinders. The influence of the external electric resistance on the reduction of sulfate and on the electric power generation was investigated. The experimental results show that there is an optimum value for the external resistance. There is a trade-off between the reaction rate and the overpotential losses; these parameters have influence on the microorganisms acclimation time and electric power. The maximum electric power generated was 5.47 W/m2 and it was related to a relatively low external electric resistance (61.7 Ω) when compared to values documented in the literature. Also, the sulfate concentration at the cathode was reduced 99% (270 Ω). These preliminary results support the use of MFCs for AMD remediation and cost reduction to the available conventional technologies.
Keywords
Microbial fuel cells, acid mine drainage, energy generation, sulfates
