Use of Green Hydrogen Electrolyzer Byproduct Oxygen for use in Wastewater Applications

The US Department of Energy has established the Hydrogen Energy Earthshot goal to reduce the cost of clean hydrogen to $1 per 1 kilogram in 1 decade (“111”). Water electrolysis using electricity generated from renewable energy technologies is the cleanest way to produce hydrogen resulting in zero greenhouse gas emissions. One of the key aspects that’s not commonly discussed is the utilization of oxygen, a byproduct of hydrogen production via water electrolysis. Technically, oxygen is a harmless gas and can be vented to the atmosphere. However, it is prudent to explore the large-scale utilization of by-product oxygen to improve the economic efficiency of hydrogen production through electrolysis. Wastewater Treatment Plants (WWTPs) using the activated sludge technology are known to consume large amounts of oxygen in the aeration step. Currently, the majority of WWTPs use air for aeration. Energy costs for aeration can range from 15% to 49% of the total operating cost for a WWTP. Use of pure oxygen can significantly reduce the volume of gas required for aeration, thereby cutting down the associated energy costs. In this paper, we explore the technical and economic feasibility of synergistic integration of oxygen byproduct from electrolysis for wastewater treatment.