Ultraviolet (UV) disinfection is widely used in municipal wastewater and reuse systems, yet its full-scale outcomes depend strongly on how fluence is delivered under real-water conditions rather than on nominal lamp output. This review consolidates the photochemical basis and plant-relevant limitations of UV disinfection, with emphasis on key factors such as matrix optics (e.g., UVT254, color, and turbidity/suspended solids) and particle shielding. Building from these constraints, UV-enhanced disinfection is examined as an engineering strategy that couples UV with oxidants or catalytic/physical processes to expand inactivation pathways and improve robustness in challenging effluents. Representative configurations have been reported (e.g., UV/free chlorine, UV/monochloramine) and are compared in terms of dominant reactive species and reaction networks, matrix dependence and scavenging effects, disinfection performance trends across microbial targets, and process-specific trade-offs including transformation products/disinfection byproducts, energy and chemical demands, and materials durability. Finally, practical considerations for implementation are summarized, including monitoring and control variables, validation approaches (e.g., biodosimetry, challenge testing), and operating windows that balance inactivation with risk and resource inputs, to support more reliable selection and operation of UV and UV-hybrid disinfection for water reuse.

Electroplating wastewater treatment is governed not only by total heavy-metal concentrations but also by metal speciation, organic complexation, salinity, intermittent discharge, and increasingly stringent requirements for water reuse and metal recovery. This review reframes recent advances from a removal-efficiency-centered perspective to a speciation-driven and resource-oriented framework. Treatment technologies are evaluated according to their dominant mechanisms, including precipitation and phase transfer, ligand destruction and redox conversion, selective separation, electrochemical recovery, biological transformation, and hybrid process integration. Attention is paid to the fate of metals after treatment, the management of sludge, regenerants, and membrane concentrates, and trade-offs among removal efficiency, resource recovery, energy and chemical demand, operational stability, and engineering applicability. The analysis indicates that no single technology is likely to simultaneously address complexation, high salinity, membrane fouling, biological inhibition, and low-carbon operation. Future systems should therefore integrate source-separated collection, speciation-targeted pretreatment, selective metal recovery, water reuse, concentrate management, and digitally assisted process control. This review provides a mechanistic and decision-oriented framework for designing sustainable electroplating wastewater treatment systems beyond conventional end-of-pipe removal.