Industrial wastewater from sectors such as the sugar industry contains persistent organic pollutants—including melanoidins, lignin-derived compounds, and residual carbohydrates—that are resistant to conventional treatment and pose significant environmental risks. Advanced oxidation processes (AOPs) offer a promising route for degrading these contaminants through in‑situ generation of highly reactive species such as hydroxyl radicals (•OH). However, standalone AOPs often suffer from limited radical production and incomplete degradation. This study proposes a modular hybrid AOP system that synergistically integrates hydrodynamic cavitation (HC) with immobilised photocatalysis (PC) to enhance •OH generation and pollutant breakdown. Synthetic sugar industry wastewater was formulated and characterised, and a commercially available TiO₂ photocatalyst was immobilised onto a cylindrical borosilicate reactor to enable catalyst reuse and improve operational stability. Two vortex-based cavitation devices were evaluated, with the PC reactor positioned downstream to form the hybrid HC–PC setup. The system's performance will be quantified using •OH radical consumption metrics and assessed through a Synergistic Index (SI), where SI > 1 signifies beneficial hybridisation. Optical simulations in ANSYS SPEOS were employed to optimise light distribution in the immobilised PC reactor, with irradiance measurements confirming model accuracy. This work establishes one of the first systematic benchmarks of HC–PC hybrid systems, supporting future scale‑up and modular deployment for sustainable wastewater remediation.