Wastewater emerges as a practical source for clean hydrogen
(Photo: Princeton University)
28 October 2025 – Engineers at Princeton show that treated wastewater can replace clean water in electrolyzers used to produce hydrogen. In a typical electrolyzer, water is split across a membrane into hydrogen at the cathode and oxygen at the anode. Until now, most systems rely on high-purity water, which is expensive and strains local supplies. The study finds that effluent from wastewater treatment plants, after standard processing, delivers similar performance while cutting water-related costs by up to about half. This makes hydrogen more attractive for hard-to-electrify industries such as steel and fertilizer. The team also evaluates possible contaminants and develops system designs that can tolerate the variable composition of wastewater.
