Magnetite-based nanoparticles and nanocomposites for recovery of overloaded anaerobic digesters

• Published in: Bioresource technology Vol. 372; p. 128632
• Main Authors: Barrena, Raquel, Vargas-García, María del Carmen, Catacora-Padilla, Paula, Gea, Teresa, Abo Markeb, Ahmad, Moral-Vico, Javier, Sánchez, Antoni, Font, Xavier, Aspray, Thomas J.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-03-2023
• Subjects: Anaerobiosis; Bioreactors - microbiology; Ferrosoferric Oxide; Flocculent sludge; Granular sludge; Hydrogenotrophic methanogens; Iron-oxide nanoparticles; Magnetite Nanoparticles; Methane; Nanocomposites; Sewage - microbiology; VFA inhibition; Flocculent sludge; Hydrogenotrophic methanogens; Iron-oxide nanoparticles; Granular sludge; VFA inhibition
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.128632

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•Iron-based nanomaterials were tested in anaerobic granular and flocculated sludge.•Magnetite-based nanomaterials were able to recover overloaded anaerobic reactors.•VFA inhibition were reversed in 30–50 days using nanomaterials.•Microbiome in granular and flocculated sludge were reestablished with modifications.•Promoted microorganisms changed the dominance towards hydrogenotrophic species.
The effect of magnetite nanoparticles and nanocomposites (magnetite nanoparticles impregnated into graphene oxide) supplement on the recovery of overloaded laboratory batch anaerobic reactors was assessed using two types of starting inoculum: anaerobic granular sludge (GS) and flocculent sludge (FS). Both nanomaterials recovered methane production at a dose of 0.27 g/L within 40 days in GS. Four doses of magnetite nanoparticles from 0.075 to 1 g/L recovered the process in FS systems between 30 and 50 days relaying on the dose. The presence of nanomaterials helped to reverse the effect of volatile fatty acids inhibition and enabled microbial communities to recover but also favoured the development of certain microorganisms over others. In GS reactors, the methanogenic population changed from being mostly acetoclastic (Methanothrix soehngenii) to being dominated by hydrogenotrophic species (Methanobacterium beijingense). Nanomaterial amendment may serve as a preventative measure or provide an effective remedial solution for system recovery following overloading.