| Résumé | In this study, to achieve low-carbon agriculture, we built an innovative flow-through hydroponic microbial fuel cell (H-MFC) to decrease rice plants' methane (CH₄) emissions. A single-chamber H-MFC equipped air-floating cathode design was modified for the hydroponic cultivation of Hayayuki rice plants (Oryza sativa L.). For comparison purposes, two H-MFCs seeded with rice (PMFC-A, PMFC-B), two H-MFCs with no plant (NPMFC-A, NPMFC-B), and two potted rice plants (Control-A, Control-B) were tested. Then, the output power density (PD), effluent chemical oxygen demand (COD), rice plant biomass yield, and methane flux emission were evaluated. PMFC showed the highest power density 504.39 mW/m³ (PDₘₐₓ), which is 4.88 times higher than NPMFC. The higher PDₘₐₓ observed in the PMFCs can be attributed to an increased hotpot of microbes’ activity in the rhizodeposition zone, leading to increased (1.45 times higher) average COD concentration in PMFCs when compared to NPMFCs. The average CH₄ emission flux in the Control (2.03 ± 5.21 mg/m²/h) was 1.97 times higher than PMFC (1.03 ± 0.05 mg/m²/h). These results showed that integrating MFC technology could decrease CH₄ emissions from rice plants in hydroponic systems. In addition, the rice plants grown in PMFC and Control have similar shoot heights (58.9±1.85 cm vs. 59±1.75 cm) and root weight (0.1964±0.0047 vs. 0.1777±0.0078). The integration of H-MFC has no significant influence on the biomass production of rice plants. |
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