Dye-contaminated wastewater is a major environmental problem that requires effective and affordable treatment methods. This study investigates an innovative approach using black sand filtration assisted by UV light to remove methylene blue (MB) dye from wastewater. The motivation is to develop a sustainable low-cost wastewater treatment technology. Black sand's composition of iron oxide and other metal oxides enables the adsorption and photocatalytic degradation of dyes. The effects of operating parameters, including pH, bed height, flow rate, and initial MB concentration, were examined using a fixed-bed column system. The maximum adsorption capacity was 562.43 mg g−1 at optimal pH 10, 15 cm bed height, 50 ppm MB, and 53.33 mL min−1 flow rate. Mathematical models effectively described the experimental breakthrough curves. For real textile wastewater, black sand with a UV lamp removed 50.40% COD, 73.68% TDS, 43.82% TSS, and 98.57% conductivity, significantly outperforming filtration without UV assistance. Characterization via XRD, XRF, FTIR, zeta potential, and SEM revealed black sand's photocatalytic properties and mechanism of MB adsorption. The findings demonstrate black sand f iltration plus UV irradiation as a feasible, sustainable technology for removing dyes and organics from wastewater. This method has promise for the scale-up treatment of textiles and other industrial effluents.