Assessing the impact of zero-valent iron nanoparticles on the semi-continuous anaerobic digestion of sewage sludge under the inherent variability of the influent
Moyano, David (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Vargas-García, María del Carmen (Universidad de Almería. Departamento de Biología y Geología)
Barrena, Raquel (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Sánchez, Antoni (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Font, Xavier (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)

Data:	2026
Resum:	The effect of nanoscale zero-valent iron (nZVI) addition was assessed during the anaerobic digestion (AD) of sewage sludge, considering the inherent variability of sludge over time. Preliminary batch experiments determined the most appropriate nZVI addition strategy, followed by a semi-continuous experiment (292 days in 2 L digesters) evaluating different nZVI concentrations (0. 3, 0. 7, and 1 g L-1) while tracking organic loading rate (OLR) fluctuations due to influent variability. Under semi-continuous operation, nZVI addition increased methane concentrations (2. 7-10. 8 %) proportional to dosage, but decreased biogas yields (3. 6-13. 6 %) and volatile solids (VS) reduction (4. 9-15. 7 %). Methane yields showed a marginal response (-4. 2 % to +2. 9 % increase), which, combined with the effect on VS reduction, suggests an increased methane potential when dosing nZVI. Variability in results using the same nZVI concentrations was partially attributed to OLR changes, ranging from 0. 8 to 1. 9 g VS L-1 day-1, as confirmed by a Generalised Linear Mixed Model, revealing a close interaction between OLR and nZVI dosing affecting methane yield. This study demonstrated a lasting influence of nZVI addition on AD, further supported by microbial analysis, which highlighted the prevalence of hydrogenotrophic methanogenesis in nZVI-dosed digesters, linked to higher methane concentrations and lower VS reduction. Overall, this research shows that methane yield in the semi-continuous anaerobic digestion of sewage sludge is influenced by the interaction between nZVI addition and OLR and, consequently, both factors must be studied simultaneously under realistic AD operation conditions.
Ajuts:	Ministerio de Ciencia e Innovación TED2021-130407B-I00
Nota:	Altres ajuts: acords transformatius de la UAB
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Generalised linear mixed model (GLMM) ; Hydrogenotrophic methanogenesis ; Methane enrichment ; NZVI ; Organic loading rate (OLR)
Publicat a:	Journal of environmental chemical engineering, Vol. 14, Num. 2 (April 2026) , art. 121806, ISSN 2213-3437

DOI: 10.1016/j.jece.2026.121806

11 p, 5.1 MB

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