July 2016

Since November 2014 Baumgarte Boiler Systems GmbH has been involved in a research project for the recovery of phosphorus from sewage sludge using the MEPHREC© process.

Phosphorus is a valuable mineral substance and a raw material that is vitally necessary for humans. It is ingested with food and is hence ultimately taken from the soil via agricultural plant production. The worldwide deposits of phosphate are, however, limited and are unfavourably located from a geopolitical/European point of view. Almost all of the phosphate for Germany has to be imported. Alternative solutions for phosphorus production are therefore particularly important.

The phosphate accumulates in the sewage sludge. The recovery of the phosphorus with a thermal process is, according to the assessments of various experts the ecologically and economically best solution. For this purpose the MEPHREC© process was developed. 

MEPHREC© stands for Metallurgical Phosphorus Recycling. In this process the dried sewage sludge is pressed into a cylindrical shape and thermally treated in a modified shaft furnace (Mephrec© reactor) together with coke and other additives. In the course of this the phosphate fuses and is removed from the furnace together with other mineral constituents and granulated. The phosphate is then available in a form that can be utilised by plants (plant available).

Within the scope of the research project a pilot plant was set up at the Klärschlammverwertung Region Nürnberg GmbH (Sewage sludge utilisation company, Nuremberg region), in which the process is being tested and further developed for continuous operation. Baumgarte Boiler Systems GmbH is responsible in this project for the engineering, delivery, construction and commissioning of the core component, the Mephrec© reactor, and associated assemblies.

In July 2016 a milestone was reached in the project. On 4.7.2016 a start was made on hot commissioning of the plant. After all pre-conditions had been met, the Mephrec© reactor was able to complete the first campaign. First of all, however, for approval reasons, still without sewage sludge briquettes, but only with coke and silicon rock. 

Now that the approval of the licensing authority has been received, in the next step the furnace will be operated with sewage sludge briquettes and the slag hence obtained will be examined to determine its phosphate content and plant availability.

If the test runs prove positive, it is to be expected that in the short term a large market will appear for this technology in Germany as well as other European countries.

The collaborative project is promoted and funded by the German Federal Ministry for Education and Research within the programme “Future-viable Technologies and Concepts for Energy-efficient and Resource-conserving Water Management”. Seven partners from the areas of science and industry are participating in the joint project.

After a successful conclusion of the project at the Nuremberg location an industrial-scale plant for phosphorus recovery from sewage sludge will be constructed.