CuO nanoparticles as modifiers for membranes for anaerobic membrane digestion

Membrane separation technologies offer a promising solution for anaerobic digestate treatment but are limited by membrane fouling and reduced flux. This study investigated the use of CuO nanoparticles (NPs) on ultrafiltration membranes to mitigate fouling and improve separation performance during digestate treatment. CuO NPs were synthesized via a sonochemical process and deposited onto NADIR® UP150 T membranes. The modified and unmodified membranes were evaluated using anaerobic sludge from a pilot-scale anaerobic digester under two operational modes: continuous and intermittent with reverse flow cleaning. Results showed that although modified membranes had slightly lower initial permeate flow rates, they exhibited greater stability over time and reduced fouling rates compared to the unmodified membrane. Under intermittent cleaning, the unmodified membrane displayed the highest cleaning impact, with a 100% increase in permeate flow post-cleaning, versus 66.7–88.9% for coated samples. The findings suggest that CuO-modified membranes can provide a trade-off between fouling resistance and flux performance, particularly in systems with limited cleaning capacity.