The potential of integrating solar-powered membrane distillation with a humidification–dehumidification system to recover potable water from textile wastewater

Abstract

Textile production is energy- and water-intensive, and membrane distillation (MD) has shown potential for reclaiming potable water from textile wastewater. However, in the current state, the energy and water recovery potential of MD is lower compared to other conventional distillation technologies. To address these issues, this study proposes and assesses a novel solar-powered hybrid Sweeping Gas MD (SGMD) unit integrated with a humidification dehumidification (HDH) system. Real textile wastewater from bleaching and dyeing processes is treated in the hybrid SGMD-HDH system to recover freshwater. An optical-thermal sub-model for the parabolic trough collector and the heat and mass transfer model for the dehumidifier are developed and validated using experimental measurements. The results reveal that the hybrid SGMD-HDH can exhibit nearly 20 % higher water flux and 50 % higher gain output ratio (GOR) compared to the standalone MD system. The highest water production and average GOR for bleaching wastewater feed solution reached 11.72 kg/day and 0.64, respectively. The higher concentration of chemical contaminants in dyeing wastewater decreased water flux and GOR by up to 14 % and 10 %, respectively, compared to bleaching wastewater. Elemental analysis showed increased carbon concentrations on the polytetrafluoroethylene membrane surface arising from organic fouling.