Dialysis opens a new pathway for high-salinity organic wastewater treatment

High-salinity organic wastewaters pose a major challenge for conventional wastewater treatment processes. Here we propose dialysis as an innovative solution to overcome this challenge. Dialysis uses an ultrafiltration (UF) membrane that allows the passage of salts while rejecting the organic substances, operating in a bilateral countercurrent flow mode without the application of hydraulic pressure. Using bench-scale experiments and a model for salt and water transport in leaky membranes, we demonstrate that dialysis can effectively desalinate high-salinity organic wastewaters without diluting the wastewater stream. By comparing the salt/organic selectivity of dialysis and UF using the same membrane, we show that dialysis can effectively fractionate salts and organic substances in high-salinity organic wastewaters. Additionally, we find that, unlike UF, dialysis is almost unaffected by membrane fouling, highlighting its excellent fouling resistance. We conclude by proposing potential high-salinity organic wastewater treatment schemes based on dialysis, paving the way for more sustainable and effective management of challenging wastewaters.