Assessing the impact of zero-valent iron nanoparticles on the semi-continuous anaerobic digestion of sewage sludge under the inherent variability of the influent
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 ex...
| Authors: | , , , , |
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| Format: | article |
| Publication Date: | 2026 |
| Country: | España |
| Institution: | Universitat Autònoma de Barcelona |
| Repository: | Dipòsit Digital de Documents de la UAB |
| Language: | English |
| OAI Identifier: | oai:dnet:uabarcelona_::b8dc6b17dffa1e17c731c14dbdd5106e |
| Online Access: | https://ddd.uab.cat/record/327415 https://dx.doi.org/urn:doi:10.1016/j.jece.2026.121806 |
| Access Level: | Open access |
| Keyword: | Generalised linear mixed model (GLMM) Hydrogenotrophic methanogenesis Methane enrichment NZVI Organic loading rate (OLR) |
| Summary: | 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. |
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