From Nanomaterial Performance to System Integration: Advancing Realistic Wastewater Treatment Technologies

Nanotechnology offers transformative potential for wastewater treatment, yet its full-scale implementation remains bottlenecked by the “lab–reality gap”. While bench-scale studies using idealized matrices report outstanding pollutant removal efficiencies, performance routinely deteriorates in authentic wastewater due to complex matrix interferences, natural organic matter (NOM) competitive binding, fouling dynamics, and unpredictable nano–bio transformations. Moving beyond traditional reviews that focus heavily on material synthesis and theoretical capacities, this review provides a novel, systems-oriented, and function-driven perspective on environmental nanotechnology. We critically evaluate the operational stability and behavior of nano-enabled systems under realistic conditions, categorizing nanomaterial roles into reactive interfaces, selective barriers, signal generators, and biological modulators. Crucially, this work examines the synergistic integration of nanotechnology with advanced oxidation processes (AOPs), membrane bioreactors, and digital intelligence—including artificial intelligence (AI) and real-time nanosensing—to achieve smart fouling management and circular resource recovery. Finally, we propose a comprehensive, multidimensional evaluation framework that simultaneously assesses technical efficiency, stability, scalability, economic feasibility, environmental safety, and system compatibility. This review delivers a pragmatic roadmap to bridge the chasm between isolated laboratory discovery and robust, sustainable, field-scale wastewater engineering.