To treat its wastewater the city of Frankfurt am Main operates two wastewater treatment plants – one in Niederrad and the other in Sindlingen. Operating under the name Stadtentwässerung Frankfurt am Main (SEF). Combined they clean the wastewater of 1,14 million people from Frankfurt and the neighbouring communities.
At the Sindlingen site, Frankfurt has an additional plant for the mono-combustion of the sewage sludge produced, which currently results in about 7,000 t/a ashes. The SEF has been involved in projects for phosphor-recycling (p-reccyling) from sewage sludge incineration ash since 2005. This includes support of university research as well as its own initiatives, including laboratory tests and a large-scale trial to recycle the ash in an electrothermal process for phosphor-recovery (“Thermophos Vlissingen”).
Due to the foreseeable need of p-recyling in the future, the SEF expanded its analytical scope of its ash investigations significantly compared to the prescribed legal obligations. For more than 20 years, the SEF examines more than 30 defined sewer nodes in the catchment area for various heavy metals in the wastewater.
The cooperation with Glatt is part of the research project Regional Phosphorus Recycling in the Rhine-Main area under consideration of industrial and agricultural material cycles (RePhoRM) by the German Federal Ministry of Education and Research.
More about the RePhoRM project.