New sewage treatment plant in Cologne

Doosan Lentjes has secured two key contracts for a new sewage sludge treatment plant in Cologne, marking a renewed deployment of its proprietary environmental technologies in Germany. The company will handle engineering, supply, installation, and commissioning of core systems, including the bubbling bed furnace, steam generation, sludge conveyance and drying, as well as a full flue gas cleaning system.

The facility, owned by KLAR GmbH, will thermally treat municipal sewage sludge from Cologne and nearby areas, ensuring safe, efficient, and fully compliant disposal. It is designed to meet strict odour regulations while enabling phosphorus recovery from the resulting ash—an increasingly important requirement under upcoming legislation.

At the core of the plant is a bubbling bed furnace, chosen for its high efficiency in thermal recovery due to excellent heat and mass transfer. An advanced heat recovery and power generation concept will allow the plant to operate largely self-sufficiently.

To meet stringent emission standards, Doosan Lentjes will install a multi-stage flue gas cleaning system. This includes an electrostatic precipitator, a Circoclean® reactor for removing acidic pollutants and heavy metals, and a fabric filter for residue capture. A downstream wet cleaning process—featuring acidic and alkaline stages—further reduces emissions. The wastewater-free system also incorporates continuous monitoring to ensure compliance with the highest environmental standards.

This project strengthens Doosan Lentjes’ position in Germany’s growing sewage sludge treatment market, driven by tighter regulations and mandatory phosphorus recovery starting in 2029. It represents a significant step in expanding the company’s mono sewage sludge treatment portfolio while supporting sustainable waste management and resource recovery.