The tofu industry produces wastewater with high concentrations of total nitrogen (Total-N) and phosphate, which can pose serious environmental hazards if left untreated. This study investigates the performance of a continuous photocatalytic reactor using Resin-Immobilized Photocatalyst-ZnO (RIP-ZnO) in reducing these contaminants. The reactor was operated with three variations of RIP-ZnO mass (25, 37.5, and 50 g) and different distances between the UV lamp and water surface (0, 10, and 20 cm). Wastewater samples were collected intermittently at four time intervals (0, 4, 8, and 12 hours) to evaluate the residual concentrations of Total-N and phosphate, in accordance with SNI 6989.11:2019 standards. Among all tested combinations, the optimal result was achieved at the 4-hour sampling point using 37.5 g RIP-ZnO and a UV lamp distance of 0 cm, where the residual Total-N concentration was 19.60 mg/L and the residual phosphate concentration was 16.9 mg/L. The highest initial concentrations reached up to 70.35 mg/L for Total-N and 36.85 mg/L for phosphate. The removal mechanism involved photocatalytic oxidation by hydroxyl radicals (•OH) generated by ZnO and ion exchange facilitated by the resin matrix. Statistical analysis using one-way ANOVA showed that sampling time significantly influenced pollutant removal (p < 0.05), while UV lamp distance had a less pronounced effect. RIP-ZnO demonstrates high removal efficiency within the early operational phase of the reactor. However, prolonged usage beyond 4 hours leads to increased residual concentrations due to catalyst saturation. Therefore, operational timing and catalyst regeneration are critical considerations for maintaining optimal performance in continuous wastewater treatment systems.