The application of membrane biofilm reactor for carbon emission reduction: A waste-to-waste strategy

Abstract

The escalating global climate crisis, driven by greenhouse gas emissions such as methane and carbon dioxide, necessitates the development of efficient, economical, and sustainable carbon reduction methods. Membrane biofilm reactors (MBfRs) utilizing gaseous substrates exhibit several advantages in wastewater treatment and hold significant promise for the utilization of waste gas as a resource. This review focuses on the operational principles and process characteristics of MBfRs, evaluate their carbon reduction potential, particularly in methane and carbon dioxide utilization, and highlight the latest advancements in using MBfRs for integrated treatment of wastewater and waste gases. Key findings indicate that MBfRs efficiently utilize methane and carbon dioxide as electron donors and carbon sources, achieving high methane utilization rates and concurrently removing a range of oxidizing contaminants, including nitrates, perchlorates, and selenates. Furthermore, CO₂ within MBfRs functions as a pH regulator and a carbon source for microbial fixation, thereby contributing to carbon fixation and resource recovery. Theoretical analyses and process comparisons suggest that MBfRs have the potential to significantly enhance carbon fixation. Additionally, the incorporation of MBfRs into flue gas treatment systems holds promise for the simultaneous removal of CO₂, NOx, and SOx, along with heavy metals, providing a holistic approach to waste gas management. Despite these advancements, the large-scale deployment of MBfRs necessitates a further comprehensive cost-effectiveness assessment and an in-depth investigation into the mechanisms underlying the simultaneous treatment of wastewater and waste gases.