Work

Valorization Phragmites australis biomass enhancing biomethane production: A comparison of electrohydrolysis vs ultrasonic and microwave pretreatments

Year: 2026

Type: article

Abstract: This work studies the pretreatment of milled Phragmites Australis biomass straw suspensions, with the aim to maximize biomethane production trough subsequent anaerobic digestion. Three pretreatment techniques as Ultrasound (US), Microwave (MW) and Electrohydrolysis (EH) were assessed, using the same theorical power applied (10000 to 30000 kJ·kg-1 TS). Subsequently, batch anaerobic digestion assays were carried out during 30 days measuring biochemical methane production. Special attention was paid on checking the possible advantages or disadvantages of the novel EH option vs the other two options. None of the three pretreatments caused significant changes in pH nor electrical conductivity which could be detrimental to subsequent anaerobic digestion process. Increasing energy dose in the US and MW cases produced an improvement in methane production from 70% (without pretreatment) to approximately 90% of the total theoretical value for energies of 30000 kJ kg-1TS. In the EH case, a clear positive effect was observed, in which 100% anaerobic biodegradability was achieved using only 15000 kJ kg-1TS. However, for higher EH energies, there was a clear decrease in methane production. It was observed that EH seems to be an aggressive technique that caused important structural changes in lignocellulosic material, reducing their lignin content while slightly solubilizing particulate carbon. Aerobic biodegradability peaked at around 15,000 kJ kg−1TS, after which unidentified biological inhibitors generated mild toxicity. EH appears to be promising pretreatment, although the mechanisms leading to inhibition of biomethanation at elevated energy levels require further investigation.

Source: Environmental Technology & Innovation

DOI: 10.1016/j.eti.2026.104756

Authors: Julio A. Gutiérrez-González, Martin Muñoz-Morales, Ester López-Fernández, Javier Llanos, José Villaseñor

Institution: University of Castilla-La Mancha

Language: English

Topic: Anaerobic Digestion and Biogas Production

Subfield: Building and Construction

Field: Engineering

Domain: Physical Sciences

SDGs: Affordable and clean energy, Responsible consumption and production, Climate action

Open Access status: gold

Estimated APC paid: $2,930