External ceramic membrane contactor for in-situ H assisted biogas upgrading.

Biological H-assisted biogas upgrading has gained significant attention as an environmentally friendly substitute to common physico-chemical upgrading techniques, but is largely limited by the low solubility of H. This study evaluated the design of a ceramic membrane contactor module for H injection. H dissolution was maintained at high efficiency by controlling gas supply and sludge recirculation rate, achieving a biogas quality of average 98.8% CH during the stable operation phase with a 108% increase in the CH production rate. This also outperforms conventional H injection using diffuser sparging which could only achieve a biogas quality of 84% CH content. Microbial community analysis found high Methanobacterium spp. abundance within the archaea at 95.2% at the end of the operation, allowing the dominance of the hydrogenotrophic methanogenesis pathway for high upgrading efficiencies. The system is a high-performance external membrane connector module coupled to common anaerobic digestion systems for biogas upgrading.