Optimized Lamella Separator Pretreatment for Reducing Organic and Suspended Pollutant Loads to Enhance Ultrafiltration Membrane Performance in Industrial Wastewater Treatment

Abstract

This study evaluated the performance of an optimized lamella separator as a pretreatment unit to reduce organic and suspended pollutant loads and improve ultrafiltration membrane performance in industrial laboratory wastewater treatment. The integrated system combined lamella sedimentation and membrane filtration to enhance contaminant removal efficiency while minimizing membrane fouling. Wastewater samples were analyzed for pH, turbidity, total suspended solids (TSS), chemical oxygen demand (COD), biological oxygen demand (BOD), and heavy metals (Cu, Pb, and Hg). The lamella separator demonstrated high effectiveness in reducing suspended pollutants, achieving removal efficiencies of 80% for turbidity and 75% for TSS. However, removal of dissolved organic pollutants was relatively limited, with COD and BOD reductions of approximately 30% and 25%, respectively. Subsequent ultrafiltration significantly improved treatment performance, resulting in cumulative removal efficiencies of 98.8% for TSS, 98% for turbidity, 79% for COD, and 85% for BOD. Heavy metal concentrations were also substantially reduced, with Cu, Pb, and Hg removal efficiencies reaching approximately 95%, producing permeate that complied with environmental discharge standards. Membrane performance analysis showed an initial flux of 100 L m⁻² h⁻¹, which decreased by approximately 35% after 8 h of continuous operation due to reversible cake-layer fouling. Periodic backwashing successfully restored membrane flux to approximately 90% of its initial value. Operational optimization indicated that a hydraulic retention time of 60 min in the lamella separator and an operating pressure of 2 bar provided the most stable and efficient system performance. The results confirm that lamella separator pretreatment effectively decreases pollutant loading to the ultrafiltration membrane, thereby improving membrane stability and extending operational lifespan. This integrated system offers a sustainable and efficient alternative for industrial wastewater treatment with lower secondary waste generation compared with conventional adsorption- or chemical-based methods. Future studies are recommended to investigate long-term pilot-scale performance, economic feasibility, membrane lifespan under continuous operation, and integration with advanced cleaning or hybrid treatment technologies to further improve process sustainability and fouling control.