Electrochemical process of chlorination and energy generation as viable alternatives for SWRO brine valorization

The number of desalination plants worldwide increased exponentially in the last decade. This is basically a consequence of fast population growth combined with the expansion of water scarcity zones, even though desalination processes are, comparatively, much more energy intensive than other freshwater membrane treatment processes. SeaWater Reverse Osmosis (SWRO) has gained preference among the most used desalination processes due to its compacity, flexibility and energetic efficiency. However, desalination processes produce a concentrated brine that needs to be disposed of and represents an environmental challenge to be tackled. Currently in the literature, the most explored solutions for brine treatment are based on the extraction of valuable resources from the concentrate, also called brine valorization. Late discussions have pointed out that other approaches such as reuse for energy production and disinfection products might also be a solution for the same challenge. This review presented the current state of the art of SWRO brine valorization including the following methods: disinfectant (chlorine) production and salinity gradient energy generation; expanding the possibilities for brine treatment and reuse.