Electrolysis for ammonia removal and hydrogen generation in urban wastewater: Innovative approaches to the water crisis

The global water crisis poses significant challenges, with millions lacking access to clean drinking water and increasing water scarcity affecting urban areas worldwide. This study explores the electrolysis of urban wastewater as a two-fold solution for ammonia (un-ionized NH 3 , and ionized NH 4+ ) removal and hydrogen gas (H 2 ) production. Traditional treatment methods often fail to remove ammonia efficiently, underscoring the need for innovative approaches. Electrolysis, known for its versatility, energy efficiency, and environmental friendliness, emerges as a promising solution in wastewater treatment applications. This research utilized a dimensionally stable electrode (DSA) comprising a Ru-Ir anode and a stainless-steel cathode to electrochemically oxidize ammonia and produce H 2 . The study investigates the effects of current density, J (83.33–416.6 A/m 2 ) on the treatability of urban wastewater. Maximum H 2 production was achieved at J of 416.6 A/cm 2 after 300 min reaction time. Under optimal conditions (333.3 A/m 2 , 0.5 mm inter-electrode distance, and 300 min of operation), the process achieved removal efficiencies of 98.94 % for ammonia, 78.18 % for total suspended solids (TSS), 50.73 % for chemical oxygen demand (COD), and complete removal (∼100 %) of total coliforms. Gas chromatography (GC) assessed the composition of gases of interest generated during electrolysis. This approach addresses environmental pollution and freshwater scarcity and generates an energy resource, presenting a scalable solution for cities worldwide facing similar challenges. • Electrolysis Wastewater Treatment Process. • Hydrogen Production from Wastewater Treatment. • Ammonia Removal for Urban Wastewater. • Real City Wastewater Treatment. • Electrode Materials for Hydrogen Production and Ammonia Removal.