Harnessing salinity gradient energy: Pushing forward in water reclamation via on-site reverse electrodialysis technology.

Effluents from urban wastewater treatment plants (UWWTPs) discharged into water bodies such as the sea or ocean, offer a potential source of renewable energy through the salinity gradient (SGE) between seawater and treated water. The European project Life-3E: Environment-Energy-Economy aims to demonstrate an innovative process integrating renewable energy production with water reclamation. Using reverse electrodialysis (RED) technology, SGE can power tertiary wastewater treatment processes in coastal UWWTPs, offsetting energy costs associated with water regeneration and reuse.

Design of a Reverse Electrodialysis Plant for Salinity Gradient Energy Extraction in a Coastal Wastewater Treatment Plant.

The chemical potential difference at the discharge points of coastal Wastewater Treatment Plants (WWTPs) uncovers the opportunity to harness renewable salinity gradient energy (SGE). This work performs an upscaling assessment of reverse electrodialysis (RED) for SGE harvesting of two selected WWTPs located in Europe, quantified in terms of net present value (NPV). For that purpose, a design tool based on an optimization model formulated as a Generalized Disjunctive Program previously developed by the research group has been applied.