Low cost and renewable H₂S-biofilter inoculated with Trichoderma harzianum

ABSTRACT

The use of biogas to produce hydrogen is currently gaining more attention. One of the drawbacks for the valorization of biogas is the presence of H₂S, a hazardous molecule that can cause damage in the metallic internal structures of industries. In this study, the H₂S-removal performance of a fungi-based biofilter was investigated. First, an H₂S-resistant fungal species was isolated from an industrial digestate and identified as Trichoderma harzianum. The capacity of this microorganism to metabolize H₂S in a mineral medium was confirmed. Then, a bioreactor was constructed and put in place to monitor the elimination of gaseous H₂S. A mix of cardboard, perlite, woodchips, and wood pellets was used as filling. Microbial development and the outlet gas composition were monitored during a 60-day experimental process during which H₂S was completely removed. 97% of the introduced sulphur was detected in the used filling material (fungal species + packing material) by elemental analysis. 24% of the detected sulphur was identified by ion-exchange chromatography as SO₄^2-. Elemental analysis, gas chromatography, and ion-exchange chromatography were used to determine the bioreactor sulphur balance. Metagenomic analysis underlined that H₂S elimination was due to the presence of Trichoderma harzianum with a H₂S-specific bacterial consortium.

KEYWORDS:

• Biofilter
• H₂S removal
• biogas purification
• Trichoderma harzianum

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that source data and underlying data are included within the manuscript. Additional extended data is available upon request.

Additional information

Funding

This work was supported by the Région Hauts-de-France, Fonds Européen de Developpement Régional (FEDER), Agence De l’Environnement et de la Maitrise de l’Energie (ADEME), Neo-Eco and Université du Littoral Côte d’Opale.