Revolutionizing energy-efficient wastewater treatment: 3D-printed beads for quorum quenching MBRs

Membrane bioreactors (MBRs) are widely applied in municipal wastewater treatment due to their high effluent quality and compact footprint; however, their broader implementation is limited by severe membrane biofouling, which leads to increased transmembrane pressure (TMP), higher energy demand, and frequent chemical cleaning. In this study, additively manufactured three-dimensional (3D) printed quorum quenching (QQ) beads were developed and evaluated as an innovative biofouling control strategy in a long-term pilot-scale MBR treating real municipal wastewater. The QQ beads consisted of a mechanically robust 3D-printed polylactic acid (PLA) skeletal structure filled with a sodium alginate matrix immobilizing Rhodococcus sp. BH4. The system performance was assessed over 60 days and compared with a control MBR operated without active QQ media. Results demonstrated a substantially slower TMP increase in the QQ-MBR, with an approximately 65% reduction in cumulative fouling load relative to the control system, while maintaining high and stable chemical oxygen demand (COD) removal efficiencies (>85%). Biomass characteristics in the QQ-MBR showed improved stability, reflected by a consistently higher MLVSS/MLSS ratio. Techno-economic analysis extrapolated to full-scale operation indicated that the integration of 3D-printed QQ beads can reduce chemical cleaning requirements and overall operating expenditures without imposing a significant additional cost. Overall, the findings demonstrate that 3D-printed QQ beads provide a durable, reusable, and economically feasible approach for effective biofouling mitigation, supporting the scalability of quorum quenching-based MBR technologies.