The tea industry generates large volumes of wastewater containing high concentrations of organic matter and suspended solids, leading to elevated chemical oxygen demand (COD) and biochemical oxygen demand (BOD). This study reports the fabrication of ultrafiltration membranes based on cellulose acetate (CA) and poly(eugenol) (PE) at a mass ratio of 7:3 (w/w), modified with sorbitol, 3-glycidoxypropyltrimethoxysilane (GPTMS), and TiO2 nanoparticles. Membranes were prepared via phase inversion and characterized using SEM and FTIR. Performance was evaluated in terms of water flux, turbidity (NTU), total dissolved solids (TDS), COD, and BOD rejection. The optimized membrane composition (1 mL sorbitol, 2.5 mL GPTMS, 2.5 g TiO2) exhibited a flux of 36.11 L m−2 h−1, with rejection efficiencies of 83.42% (NTU) and 76.28% (TDS). Furthermore, COD was reduced from 2215 to 165 mg/L (97.83% removal) and BOD from 1327 to 117 mg/L (91.18% removal), meeting national discharge standards. The high removal efficiency is attributed to the synergistic mechanisms of size exclusion by the dense selective layer and adsorption of phenolic compounds through the aromatic structure of PE. These findings demonstrate that CA/PE hybrid membranes with GPTMS–TiO2 modification offer a sustainable and highly effective approach for tea industry wastewater treatment.