Study on the use of oxygen from an electrolyzer in waste water treatment at the Landau-Mörlheim sewage treatment plant

Project duration: 05/2022 - 03/2023

Project editing by: 

rewa

Project editior: 

Dipl.-Ing. Oliver Gretzschel

Dipl.-Biophys. Linda Müller

Prof. Dr.-Ing. Heidrung Steinmetz

Funding:

Waste Disposal and Economic Operations Landau AöR

Project partners:

HYDRO Engineers Energy & Water GmbH

Wupper Association for Integral Water Management mbH

Fraunhofer Institute for Systems and Innovation Research

Project description:

The linking of regenerative energy generation and the resulting storage requirements in the energy grid with the elimination of micro-pollutants at municipal wastewater treatment plants represents an innovative and forward-looking approach. This approach was investigated in detail in the KMU-innovativ joint project eloise (2022) and is currently being implemented at the Mainz wastewater treatment plant. The Entsorgungs- und Wirtschaftsbetrieb Landau (EWL), together with other partners, is planning to set up an electrolyzer near the Landau wastewater treatment plant. The resulting products, heat and oxygen, are to be used at the site in a targeted and resource-saving manner. The aim of EWL is to use the oxygen for the aeration of the activated sludge stage also under the aspect of viticulture. In addition, the use of the oxygen for a more advanced wastewater treatment with elimination of trace substances is being examined. The basic investigation regarding the use of electrolysis oxygen for aeration goes beyond the measures planned in Mainz and also the aspects of deodorization currently being investigated at the Trier wastewater treatment plant and thus clearly distinguishes the projects from each other.

The electrolysis itself, as well as the use of the hydrogen, are not the subject of this study and will be investigated in detail by the client itself.

A major focus of the feasibility study to be carried out is the examination of the possibility to (co-)use the oxygen produced during electrolysis for aeration of the aeration basins. For this purpose, both the experience with oxygen aeration available in Landau and the special constellation (campaign operation in viticulture) will be taken into account.

For the elimination of trace substances, besides activated carbon adsorption, elimination by means of ozone treatment can also be considered. Electrolysis fulfills the function of providing oxygen as a starting product for ozonation. Thus, there is a resource-efficient utilization option for this "by-product" of the electrolysis process at the wastewater treatment plant. The ozonated wastewater can subsequently be passed through an activated carbon filter (ACF) to eliminate possible transformation products.

Another important aspect of making the operation of an electrolyzer as efficient and resource-saving as possible is the use of the waste heat flows generated during operation. The waste heat generated is to be examined in more detail with a view to possible utilization paths at the wastewater treatment plant or the adjacent technology park.