Improving Recovery of Valuable Bio-Products from Sewage Sludge Using Innovative Membrane Technologies

Membrane bioreactor (MBR) technology has been employed in sewage sludge treatment within polyhydroxyalkanoate (PHA) production systems to tackle challenges like sustainable recovery of volatile fatty acids (VFA) and achieving high-quality effluent. Typically, MBRs utilize pressure-driven membranes, mainly ultrafiltration (UF) membranes. Despite its advantages, membrane fouling remains a significant hurdle, particularly when scaling up from laboratory-scale to pilot and full-scale plants. Living Membranes® (LM) offer a novel approach to self-forming dynamic membranes (SFDM), relying on the formation of a stable layer of sludge particles, organic compounds, and microorganisms between a cost-effective supporting materials. LM® reframes membrane fouling from a drawback to a key part of the treatment process. Being composed of organic materials, the encapsulated layer within LM® serves as both a carbon source and a nutrient trap, promoting microbial growth and ensuring high contaminant removal. This abstract presents insights from the application of pilot-scale ultrafiltration membrane bioreactor (UF-MBR) and Living Membrane® bioreactor (LMBR) for PHA production. The UF-MBR and LMBR technologies have been compared under both anaerobic conditions, aimed at VFA production via sewage sludge acidogenic fermentation, and aerobic conditions, mainly focused on the removal of contaminants. Preliminary results suggest that LM® offers a sustainable and efficient alternative to conventional UF membranes in sewage sludge treatment, potentially enhancing the recovery of valuable resources such as clean water, VFAs, and PHA.