This study at AAU, conducted under the CORNERSTONE project, explores the application of MD for treating wastewater from the steel industry and other industry. MD offers significant advantages, including the utilization of low-grade heat, the ability to treat highly concentrated wastewater, high water recovery rates, and near-total rejection of non-volatile solutes. Experiments were performed in direct contact MD mode using a polypropylene (PP) hollow fiber membrane with a pore size of 0.2 µm and 73% porosity. The feed inlet temperature was varied between 40 °C and 60 °C, while other operating parameters remained constant. Performance was evaluated based on permeate conductivity and flux. Results demonstrated stable flux over time, indicating minimal membrane fouling or wetting, with higher feed temperatures yielding increased flux due to enhanced driving forces. The MD module were able to recover 93% of water from the steel industry without loosing its performance. Permeate conductivity ranged between 1 and 5 µS/cm, achieving an overall rejection rate of 99.9% based on conductivity measurements. Modeling of the hollow fiber system revealed that increasing module length led to reduced flux and higher specific thermal energy consumption (STEC). These findings highlight the potential of MD as an effective and sustainable solution for industrial wastewater treatment, supporting water reuse and energy efficiency in line with circular economy principles.
Further studies will explore the application of MD to treat wastewater from other industries to evaluate its efficiency in achieving high-quality water reuse across diverse industrial contexts.
Picture: Schema of the MD experimental system
