Pilot-scale operation of an aquaporin-based forward osmosis process for polishing municipal wastewater effluents

Today’s aquatic environment is increasingly challenged by the accumulation of micropollutants due to human activities. A considerable amount of such micropollutants is discharged via municipal effluents. Pressurized membrane filtration technologies have shown good performance in removing micropollutants, however their operation is energy intensive and prone to fouling, leading to high operational costs. In this study, the potential in high pollutant rejection and low fouling of using seawater-driven forward osmosis (FO) membranes is investigated at pilot-scale. To investigate the potential, Aquaporin Inside® hollow fiber FO membranes were tested in batch and continuous mode in a pilot-scale FO unit (Figure 1), installed in Avedøre, Denmark. To reach high pollutant rejection, a biomimetic osmotic membrane enhanced with water-selective aquaporin proteins was used. The FO membranes were earlier reported to show a minimum rejection of 92% of all 21 micropollutant compounds using spiked water solutions at varying operational conditions [1]. The FO membrane modules with a permeate capacity up to 200 L/h were tested in a seawater-driven process, as well as in combination with disc-tube Reverse Osmosis draw recovery. The study shows the most recent results on the membranes’ micropollutant rejection, long-term operational stability as well as an evaluation of different cleaning strategies.
This study was performed within the framework of the BONUS CLEANWATER project, funded jointly by the EU, Innovation Fund Denmark, VINNOVA and the German Ministry for Education and Science.