Biomethane and biohydrogen production from an anaerobic sludge used in the treatment of rice parboiling effluent: Specific methanogenic and hydrogenic activity

• Published in: International journal of hydrogen energy Vol. 60; pp. 702 - 710
• Main Authors: Nadaleti, Willian Cézar, Gomes, Jeferson, de Souza, Eduarda, Santos, Maele, Belli, Paulo, Borges, Armando, Mohedano, Rodrigo, Libardi, Nelson, Manoel R da Silva, Flavio, Correa, Erico, Vieira, Bruno
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 22.03.2024
• Subjects: Anaerobic digestion; Bioenergy; SHA; SMA; Bioenergy; SHA; SMA; Anaerobic digestion
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2024.01.157

This study evaluated the biomethane and biohydrogen production capacity of an anaerobic sludge collected from a rice parboiling industry. Three main parameters were assess from an experimental batch with varying substrate-inoculum ratios (S/I): the final mass production, the maximum generation rate, and the reactors’ biomethane and biohydrogen yield. From the analysis of the final production and the maximum generation rate, the best S/I ratios found for the methanogenic and hydrogenic reactors were, respectively, 1.4 and 3.8 gCOD/gVSS. These proportions produced 102.65 mgCH4/gVSS and 27.96 mgH2/gVSS, reaching the following maximum generation rates: 32.91 mgCOD CH4/gVSS.h and 12.63 mgCOD H2/gVSS.h. In contrast to the methanogenic microorganisms of the studied sludge, the acetogenics allow the use of higher organic loads in the systems. However, the lowest S/I ratio (0.1 gCOD/gVSS) resulted in both the best biomethane and biohydrogen production yield, around 2.33 mol CH4/mol glucose and 2.46 mol H2/mol glucose. Compared to the maximum theoretical yields, whereas the sludge produced biohydrogen more effectively under high S/I ratios, biomethane was generated more efficiently in low S/I ratios. Finally, the anaerobic sludge can be employed as a satisfactory inoculum in anaerobic digestion and dark fermentation processes designed for biomethane and biohydrogen production. •Specific Methanogenic and Hydrogenic Activity.•Production of 27.96 mgH2/gVSS.•Satisfactory inoculum in anaerobic digestion and dark fermentation processes.