Planned sewage sludge Mono-incineration plant in Bavaria

A sewage sludge mono-incineration plant for the decentralized disposal of 3 t/h of sewage sludge located in the District of Straubing-Bogen (Lower Bavaria) is currently in process of authorization. The process technology for the fluidized bed plant with a capacity of 3.75 MW_th has been further developed to generate quality ash particularly rich in phosphorus and with a low content of pollutants, which facilitates further processing into fertilizer.

The energy self-sufficient turnkey plant will be planned and built by WEHRLE-WERK AG based in Emmendingen and specialized in Energy Technology. The engineering firm Rückert NatUrgas GmbH based in Lauf a. d. Pegnitz will accompany the planning of the complete project.

Due to the plant size, the authorization can be handled in a simplified process according to the German Legislation (“4. BImSchV“). All emission limit values will be met not only according to the German Legislation (“17. BImSchV“) but also according to the new BREF regulation.

The process technology makes it possible to convert a little bit more than 80 % of the sewage sludge ash into depolluted quality ash, which can be used for the recovery of phosphorus. Due to the thermal utilization of sewage sludge in the fluidized bed combustion system, all organic, endocrine and pathogenic pollutants are properly eliminated at temperatures of over 850 °C. The non-combustible pollutants of the sewage sludge, mostly heavy metals, will be separated from the quality ash rich in phosphorus and are nearly entirely disposed of externally together with the remaining ashes and filter residues.

Environmental experts have certified that the process is safe for the environment and that all immissions will be far below the limit values. The process also fulfills all regulations to protect the vicinity of the plant. Moreover, the design of the plant ensures that no technical wastewater will be produced.

The commissioning is planned for the second half of 2021. The concept of a decentralized disposal reduces the distances for the delivery of sewage sludge as well as the traffic-related fine dust and CO₂ emissions caused by diesel-powered trucks.