Energy generation in a novel microbial fuel cell: characterization and dynamics of microbial communities using organic matter and ammonia as electron donors

• Autor(a) principal: Vitor Cano
• Data de Publicação: 2020
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://doi.org/10.11606/T.100.2020.tde-19052020-101339

The microbial fuel cell (MFC) is a novel technology that can generate clean energy from wastes. In this study, a novel double chamber MFC with low-cost electrodes was developed and assessed to convert organic matter into electricity under different temperatures (~25, 35 and 55 °C), external resistances (13 and 300 &#937) and electron acceptors (oxygen and nitrate) and also to assess the ability to generate electricity from ammonia oxidation. The MFC was evaluated in terms of microbial community structure (16S rRNA genes sequencing), energy generation, conversion and treatment efficiency. The results showed that temperature was a crucial factor controlling the performance with Geobacter as the most dominant electrogen genus (relative abundance of 20%) on the anode at 23°C and Tolumonas, Lactococcus and Peptococcaceae at 55° (combined relative abundance > 33%). The genus Comamonas was associated to greater cathode performance at 23 °C, but at 35 and 55 °C they were not found and the highest cathode charge resistances were observed. The use of lower external resistance of 13 &#937 influenced the abundance and activity of electrogen bacteria on the anode, ultimately improving the coulombic efficiency up to 12%. With nitrate as electron acceptor, power density up to 17 W m-3 was achieved, while, with oxygen as electro acceptor in optimum operating condition (Rext = 300&#937 , 23 °C, organic loading rate of 3.64 kg COD m-3 d-1) maximum power density of 48 W m-3 was achieved. In terms of treatment, high efficiency (COD removal > 90 %) was observed regardless of the applied conditions. It was also demonstrated that, in a novel bioelectrochemical process with ammonia as electron donor, the genus Nitrosomonas was associated with current generation, electrogen bacteria adapted to oxidize ammonia, but anammox bacteria presented electric current considerably lower. So, through an interdisciplinary approach, this study contributed to the development of a technology for clean and renewable energy generation combined with wastewater treatment aimed at inorganic and organic compounds