A Comparative Study of ED and BPED Technologies for Ammonia Recovery from Wastewater.

Ammonia is a common pollutant in wastewater, and its removal is essential to prevent environmental issues such as odors and eutrophication, which can harm aquatic ecosystems and human health. While traditional treatment methods are energy-intensive and costly, ammonia has garnered attention as a carbon-free hydrogen source in the context of the global shift toward carbon neutrality. Wastewater, particularly supernatant from anaerobic digesters and leachate from sludge dewatering, often contains high ammonia concentrations, offering a potential feedstock for hydrogen production. This study compares electrodialysis (ED) and bipolar membrane electrodialysis (BPED) systems for ammonia recovery, aiming to obtain a sustainable hydrogen source from environmental public infrastructures. Energy consumption, current efficiency, pH changes, and ammonia recovery rates were thoroughly evaluated for both processes. Results show that BPED leads to higher pH and ammonium hydroxide accumulation, making it suitable for processes like membrane distillation. However, BPED exhibited higher energy consumption and lower current efficiency compared to ED. The findings suggest that both systems have distinct advantages and can contribute to ammonia recovery in wastewater treatment, supporting the development of sustainable ammonia recovery strategies for hydrogen production.