E-MetO (Electrolysis using process water as an interface for biological methanisation and ozonation) is funded by the Federal Ministry for Economic Affairs and Climate Protection with approximately €3.2 million as part of the "application-oriented non-nuclear research funding in the 7th Energy Research Programme of the Federal Government" for the areas of sector coupling and hydrogen technologies. In the project, a consortium consisting of Tuttahs & Meyer Ingenieurgesellschaft mbH, the Department of Dynamics and Operation of Technical Systems at the Technical University of Berlin, the Research Institute for Water Management and Climate Future at RWTH Aachen University (FiW), the electrolysis plant expert Aspens GmbH from Hanover and Berliner Wasserbetriebe is conducting research into the practical implementation of hydrogen technologies at sewage treatment plants.

The main focus is on the use of treated wastewater in water electrolysis, i.e. the separation of water into its components hydrogen and 
oxygen, and the subsequent storage of the hydrogen in the form of methane. This is achieved through biological methanisation of the hydrogen using CO2 from the digester gas. In addition, the storage and use of the by-product oxygen in ozonation, a process stage in advanced wastewater treatment for the targeted removal of trace substances and disinfection, is being considered.