Nutrient recovery and hydrogen production from wastewater by electrodialysis process: Optimization using response surface methodology

The increasing demand for energy, water, and nutrient management has attained interest in sustainable wastewater treatment processes. The electrodialysis (ED) process provides sustainable water and energy management thanks to both nutrient recovery efficiency and hydrogen production. In this study, the ED process has been investigated, focusing on the impact of current density, number of ion-exchange membranes, initial conductivity, and the pH of both diluate and concentrate solutions. The individual and combined effects of these parameters on ED performance were analyzed. At the same time, nutrient recovery efficiency, hydrogen production, and energy consumption values were modeled using Response Surface Methodology (RSM), where correlation equations were created and optimum conditions were determined. When the analysis results were compared with the model results, hydrogen production was determined with 95.6 % accuracy, nutrient recovery efficiency with 98.7 % accuracy, and energy consumption with 98.8 % accuracy. It was observed that the generated correlation equations successfully predicted the system operations and performance parameters. Through RSM optimization, energy consumption was reduced by 24 % in 70 % less time. 25.8 % less energy consumption was obtained for 1 mL of hydrogen production. In this way, energy and time efficiencies were achieved for better sustainability of the wastewater treatment and desalination processes.