Sustainable treatment of textile wastewater using a bio-based batch filtration system: physicochemical performance assessment and economic evaluation.

Textile industries generate large volumes of wastewater, containing high concentrations of organic pollutants, dissolved solids, and suspended particles, requiring eco-friendly and cost-effective treatment technologies. This study developed a gravity-driven bio-based batch filtration system using sugarcane bagasse fiber and coconut fiber to investigate textile wastewater treatment performance and economic feasibility. Five bagasse-to-coconut fiber ratios (100:0, 0:100, 50:50, 75:25, and 25:75) were evaluated in a multilayer filtration system. Scanning electron microscope and Fourier transform infrared analyses were performed to characterize the fiber morphology and adsorption-active functional groups before and after filtration. Among all filter configurations, the 50:50 fiber ratio demonstrated the best overall performance, achieving removal efficiencies of 79.33% for biological oxygen demand, 75.75% for chemical oxygen demand, 80.00% for total dissolved solids (TDS), 46.51% for turbidity, 77.45% for electrical conductivity (EC), and 4.82% for pH after a single filtration cycle, while maintaining pH within the Bangladesh Department of Environment permissible range. Sequential treatment cycles further enhanced treatment efficiency, achieving an overall removal of 89.17% for TDS, 81.52% for turbidity, and 88.63% for EC after five filtration cycles. Economic evaluation demonstrated a unit treatment cost of approximately 90.71 BDT/m3, significantly lower than activated carbon-based systems. These findings suggest that the proposed bio-based filtration system provides an economical, energy-free, and sustainable alternative for resource-limited regions such as Bangladesh.