INVESTIGADORES
ROMEO Hernan Esteban
congresos y reuniones científicas
Título:
Bioproduction of electricity from human urine
Autor/es:
PRUDENTE, MARIANO; ROMEO, HERNÁN ESTEBAN; BUSALMEN, JUAN PABLO; MASSAZZA, DIEGO
Lugar:
Los Cocos, Córdoba
Reunión:
Congreso; XVII Congreso Argentino de Microbiología General; 2022
Resumen:
Electro-active bacteria constitute the “driving force” of bioelectrochemical systems (BES) e.g., microbial fuel cells (MFC), which benefit from the natural ability of these microorganisms to degrade organic matter and generate electricity. A wide range of substrates have been reported as suitable fuels for BES, but one potential fuel that has been so far scarcely used is urine, mainly due to the low current densities produced when this metabolic waste is employed. This could be associated to the physical-chemical events triggered from its biological degradation, which result detrimental in the syntrophic chain needed to maintain the phylogenetic diversity responsible of the electrical charge- recovery process. In this context, the aim of this study was to evaluate the effect of using human urine on a microbial acclimation protocol, as a way of increasing the current density obtained in a BES. To avoid masking the results by possible voltage drops caused by cathode overpotential and/or cell ohmic resistance, a three-electrode bioelectrochemical reactor under controlled anode potential was used. An anaerobic sludge from a wastewater treatment plant (Institute of Materials Science and Technology, INTEMA - Mar del Plata, Argentina) was used as a microbial source. To enrich a broad mixed anaerobic inoculum in electro-active communities, graphite bars were set into a sludge-containing reactor (under stirring at 30 ºC) and externally polarized at 0.2 V (vs. Ag/AgCl reference electrode). Microbial proliferation was evaluated for 14 days by chronoamperometry for different urine dilutions. Each dilution consisted of a mixture containing a fraction of fresh urine and a fraction of domestic wastewater (so-called Syntho), rendering five different feeding media: urine (%) - Syntho (%) (v/v) equating to 10–90; 30–70; 50–50; 80–20 and 100-0. This study demonstrates that, the microbial adaptation strategy to the human urine-containing environment was effective only within a limited range (between 10-30 urine (%)). In this range, it was possible to considerably increase the current density output, generating values as high as 3.6 ± 0.2 A.m2 based on the actual anode surface area. These levels represent an over 35-fold increase compared to the values reached in similar studies. The strategy of dilution might be particularly appealing to generate electricity from source-separated urine obtained, for instance, from waterless-urinal technologies and/or urine diverting toilets, where pure urine outflows could be combined with dilutant wastewaters to meet optimum concentration requirements on demand.