June 5, 2025 (ENP Newswire) –
Could we create a cement substitute from a by-product of phosphorus recovery? Three RWTH research teams are working together on an interdisciplinary project to make this happen.
Three RWTH researchers and their teams have started working on overcoming a challenge that will not become a reality until 2029. That is because it is in this year in which most sewage treatment plant operators will be required to recover at least 80 percent of the phosphorus that is contained in their sewage sludge. Right off the bat, this sounds like a boon for both the environment and agriculture. But it brings with it a brand new problem - in the future, around 500,000 tons of mineral residues will be produced annually during this recovery process. What should we do with these huge quantities of residue? The RWTH researchers' answer is not to put them into landfill sites, but rather to use them at construction sites.
In the REARRANGE research project (Utilization Options for the Mineral Residue from Phosphorus Recovery as a Secondary Raw Material in the Industry), scientists from three departments at RWTH Aachen University are developing an innovative solution. Their aim is to use the mineral residues resulting from phosphorus recovery as a cement substitute in the construction industry.
Cement is one of the largest CO2 polluters worldwide - around eight percent of global emissions can be attributed to its production. 'If we can replace even just part of the cement, we will reduce the amount of CO2 that is produced,' explains Professor Anya Vollpracht from the Institute for Research (IBAC). In most cases, sewage sludge is incinerated, and the phosphorus is then recovered from the ash in several steps. The RWTH expert sees great potential in the material. 'I am confident that we will end up with a good product,' she says.
In addition to technical feasibility, the economic viability of the concept is also crucial. This has been assessed by Professor Peter Letmathe from the Chair of Controlling. He analyzes the conditions under which the use of the new material could be established on the market - and which political framework conditions would be necessary for this.
The researchers from the Institute of Environmental Engineering are contributing their experience to the interdisciplinary research project. 'We often investigate phosphorus recovery processes, and we also look at the recovery of other elements,' explains Dr. David Montag. Dr. Montag added that the work does not primarily investigate how the other elements from the sludge can be used, but the team aspires to make this a reality as well. The scientists evaluate the potential of industrial metals such as copper, zinc and rare earths. However, REARRANGE is primarily concerned with optimizing the quality of mineral residues for the construction industry without compromising the goal of phosphorus recovery. Before the REARRANGE research project was funded, there was an internal University seed fund in which initial tests took place.
Even if mineral residues only make up part of the cement substitute, they are still an important building block. In the future, they will enable us to have a more sustainable construction industry and a circular economy that really works. All three experts agree on this.
The project is being funded by the Volkswagen Foundation, which also supports other projects at RWTH. The Volkswagen Foundation supports research and teaching in science and technological fields. It promotes projects with a view to dealing with future issues and it is committed to strengthening the structural framework conditions at scientific institutions
(C) 2025 Electronic News Publishing
* All content is copyrighted by Industry Intelligence, or the original respective author or source. You may not recirculate, redistribute or publish the analysis and presentation included in the service without Industry Intelligence's prior written consent. Please review our terms of use.