Techno–Economic and Environmental Impact Assessment of Membrane Bioreactors for Wastewater Treatment: A Review

Despite the advantages of high effluent quality and small footprint, membrane bioreactor (MBR) technology faces challenges in sustainable development due to energy consumption and membrane fouling. Weighing the advantages and disadvantages of MBRs requires a comprehensive assessment from techno–economic–environmental perspectives. In this paper, we reviewed the related research on MBRs from three aspects: economic cost analysis, environmental impact assessment, and comprehensive techno–economic–environmental assessment. The aim of this paper is to understand the sustainable development performance of MBRs, and to review the current status of the application of multiple techno–economic–environmental assessment methods in the field of wastewater treatment. The currently available results of the economic cost analysis of MBRs showed that the operating cost and energy consumption of MBRs are higher than those of other wastewater treatment processes if MBRs’ potential benefit of smaller footprint is not taken into account. The results of the environmental impact assessment showed that MBRs have a positive environmental impact due to high quality effluent, although global warming potential limits the sustainability of MBRs to some extent. Combined techno–economic–environmental assessment showed that MBRs are economically feasible and technically efficient, while their sustainability is controversial. Given the rapid development of MBR technology, these results may evolve as new advancements are made. In addition, there is room for improvement in the existing literature regarding the reliability and comparability of results, as well as the applicability of the methods, particularly in defining the accounting scope, clarifying model assumptions, and considering discounting.