Glatt Ingenieurtechnik GmbH

Phosphorus is a plant nutrient that is essential for human nutrition. However, because natural deposits are limited, phosphorus recycling for sewage sludge will become mandatory from 2029. Glatt provides proven technology for this purpose – PHOS4green – which has been expanded to include heavy metal depletion as a crucial process step.

“Our plant is ready for your sewage sludge ash,” says Jan Kirchhof, Head of Sales at Glatt Ingenieurtechnik, inviting experts to pilot tests at the Glatt Technology Center in Weimar. Of particular interest are sewage sludge ashes with elevated heavy metal content which, thanks to PHOS4green technology at the new demonstration plant, can be converted into fertilizer granules for the agricultural industry that meet all compliance requirements.

Shaping the future of fertilizer production

PHOS4green is an innovative, patented process for recovering the essential nutrient phosphorus from ash, making it directly usable in the form of new phosphate or compound fertilizers through granulation. Acids are used to convert insoluble phosphates into a form that is bioavailable to plants. The conversion of the poorly soluble phosphate compound takes place in a suspension, the composition of which can be adjusted. The PHOS4green technology was implemented industrially several years ago. However, one widespread problem remained – that of elevated heavy metal content in sewage sludge and its ash. Without appropriate treatment, these phosphorus sources cannot be upcycled for use as fertilizer. However, Glatt now has a process for heavy metal depletion that has been successfully tested in a mobile demonstration plant. Here, experimental investigations into the redissolution and separation of heavy metals from sewage sludge ash can be carried out on a pilot scale.

Expansion of pilot trials at the technology centre

The demonstration plant for the advanced PHOS4green process was previously part of the RePhoRM project funded by the German Federal Ministry of Education and Research (BMBF[1]), which investigated the possibilities for regional phosphorus recycling in the Rhine-Main region. Following the successful completion of the research project, the five containers at the plant were set up in the outdoor area of the Glatt Technology Center in Weimar. They support and expand the testing capabilities of the current phosphorus recovery portfolio. Glatt offers customers the opportunity to test the PHOS4green process on both a laboratory and pilot scale, with granulation to individual fertilizer formulations. With the heavy metal depletion process, the recovery of valuable phosphorus as fertilizer for agriculture is now also possible for contaminated ash.

[1] Today: BMFTR – Federal Ministry of Research, Technology and Space