Minseok Im, Konan Alain Cedric Nzisso, Inhye Kim, Jeongjae Oh, Cheol Hun Park, Sunghyun Cho
Electrochemical nitrate reduction (eNO 3 - R) has emerged as a promising alternative to conventional biological denitrification for nitrate wastewater treatment, enabling the recovery of ammonia as a value-added product while eliminating greenhouse gas emissions. However, systematic evaluations of downstream ammonia separation technologies integrated with eNO 3 - R remain insufficient. This study proposes and comparatively assesses five process configurations for ammonia recovery: conventional biological treatment as a baseline, atmospheric distillation, pressurized distillation, air stripping with acid trapping, and steam stripping with neutralization. Process simulations based on the Electrolyte Non-Random Two-Liquid (ENRTL) thermodynamic model were conducted, followed by comprehensive exergy analysis, techno-economic assessment, and sensitivity analysis. The exergy analysis revealed that air stripping achieved the lowest specific exergy destruction of 2.68 GJ/kmol-N, representing a 50% reduction compared to atmospheric distillation (5.34 GJ/kmol-N). The techno-economic analysis demonstrated that steam stripping attained the lowest unit treatment cost of 61.63 USD/kmol-N at the base-case capacity, followed by air stripping (67.51 USD/kmol-N), both outperforming the biological baseline (89.94 USD/kmol-N). Electricity consumption associated with the electrolyzer constituted the dominant cost component, accounting for 37–73% of direct production costs across all eNO 3 - R configurations. Scale-up analysis indicated that air stripping exhibits the most pronounced economies of scale, becoming increasingly cost-competitive at larger treatment capacities. These findings demonstrate that eNO 3 - R integrated with stripping-based ammonia recovery offers a viable pathway for transforming nitrate wastewater treatment from a cost-intensive disposal operation into a value-generating resource recovery process.