Anaerobic Membrane Bioreactors for Livestock Wastewater Treatment and Resource Recovery: Opportunities and Challenges

Livestock wastewater is a valuable vein of resources for the production of reused water, renewable energy, and fertilizers. This review aims to provide a comprehensive understanding on the opportunities and challenges to anaerobic membrane bioreactors (AnMBRs) for livestock wastewater treatment and resource recovery. AnMBRs that integrates a membrane filtration process with anaerobic digestion exhibit high promise for livestock wastewater treatment and resource recovery. Organic matter in livestock wastewater can be biodegraded for the production of methane-rich biogas and bioactive substances, such as phytohormones, free amino acids, vitamins, and inorganic nutrients (e.g. ammonium and phosphate). Thus, the AnMBR effluent from livestock wastewater treatment can be potentially used for direct irrigation and processed for nutrient capture, for example, by struvite crystallization. Nevertheless, there remain several technical challenges to AnMBR development for livestock wastewater treatment. These mainly include digester susceptibility to inhibitory substances, low removal of antibiotics and heavy metals, and membrane fouling. Thus, recent studies have proposed several potential approaches to address these challenges to accelerate AnMBR development. These approaches can be largely classified as wastewater regulation, microbial acclimatization, process optimization, and amender addition. In this paper, we critically reviewed the performance of AnMBR for livestock wastewater treatment with respective to biogas production and contaminant removal. Key technical challenges and their potential countermeasures were delineated to shed light on further development of AnMBR in the field.