There are two main categories of hydrogen based on method of production: Blue and Green. Blue hydrogen production involves the coupling of conventional hydrogen production with carbon capture and storage. Natural gas is transformed with steam or/and oxygen (i.e., steam methane reforming or autothermal reforming). Green hydrogen involves coupling the electrolysis of water with renewable energy, making it a carbon neutral process. Both processes require large amounts of water. Water must be treated prior to chemical or electrochemical processing and also wastewater generated by the processes also need to be treated prior to discharge.

Effective water treatment for hydrogen production is essential because on the front end it must be the right quality and quantity otherwise the process will not be successful. Wastewater must meet effluent guidelines and requirements. To be truly successful the water treatment process must be completed in such a sustainable way that it reduces the demand for initial source water.