Work

Anoxic desulfurization of biogas rich in hydrogen sulfide through feedback control using biotrickling filters: Operational limits and multi-omics analysis

Year: 2025

Type: article

Abstract: Biodesulfurization is crucial for sustainable biogas purification from hydrogen sulfide (H 2 S). This study investigates the operational limits of anoxic biotrickling filters (BTFs) for treating biogas with high H 2 S concentrations (up to 20,000 ppm v ) using nitrite, along with simulated interruptions in H 2 S supply. The BTF achieved a maximum elimination capacity of 312 g S-H 2 S m −3 h −1 with an H 2 S removal efficiency of 98 % at an empty bed residence time of 284 s. A proportional-integral-derivative (PID) feedback control system was successfully employed to maintain an H 2 S outlet concentration close to the requisite setpoint (100 and 500 ppm v ) by adjusting the nitrite flow rate, thereby minimizing its accumulation. Continuous nitrite feeding after interruptions in H 2 S supply was essential to avoid H 2 S release due to sulfate-reducing bacteria. Multi-omics analyses, combining metagenomics and proteomics, revealed Sulfurimonas as the dominant sulfur-oxidizing bacteria, which downregulates most enzyme genes involved in nitrogen and sulfur metabolism in response to substrate starvation. These findings underscore the resilience of BTFs under extreme conditions and the value of multi-omics approaches in understanding microbial population dynamics, positioning BTFs as a robust solution for large-scale biogas purification.

Source: Bioresource Technology

DOI: 10.1016/j.biortech.2025.132439