Retention of Organic Micropollutants in Nutrient Recovery from Centrate by Electrodialysis─Influence of Feed pH and Current Density

Multiple barriers for micropollutants in nutrient recovery from centrate – combining membrane bioreactor and electrodialysis

“…While literature data on these three compounds is scarce, one previous study confirmed lower retention; and even showed that transport of metformin may reach up to 60% of the (unhindered) transport of inorganic salts through the membrane in ED treatment of a synthetic wastewater. 22 Moreover, in this study, retention of metoprolol was also incomplete at 90%, similar to previous studies. 20 However, as long as inorganic salts are present in the feed, which take the role of charge carriers, they will be preferentially transported compared to organic ions.…”

“…High retention of carbamazepine was also reported in lab-scale ED treatment of synthetic spiked centrate. 20,22…”

“…High retention of carbamazepine was also reported in lab-scale ED treatment of synthetic spiked centrate. 20,22 Fluctuations in removal and complementarity of barriers Fig. 3 shows that only after the second treatment stage stable and near-complete retention of organic micropollutants is achieved: the two stages act together as complementary barriers.…”

“…20 While overall removal of organic micropollutants is >90%, attempts to optimize operational parameters (electric current density, feed pH) for enhanced retention proved ineffective. 22 Furthermore, ED is faced with challenges related to wastewater reuse, as it is not suitable for removal of particulate or colloidal suspended material. 21 Still, it was shown that ED has the capacity to fully disinfect a microbially contaminated feed at high current densities.…”