Project meeting of STEP at the site of the company ATS - Agro Trading & Solutions in Hardegsen (Photo: DBFZ)

Heat Biomass gasification Biomass furnace

Project ID 03EI5411

S2P - Energy-self-sufficient recovery of phosphates through holistic sewage sludge recycling with integrated hydrogen production

Project Icon Sludge2P (Source: DBFZ)


  • 01.04.2020 – 31.03.2023


Entsorgungsbetrieb der Stadt Siegen
Goldammerweg 30
57080 Siegen

Dipl.-Ing. Uwe Siemann – project leader
Telephone: +49 (0)271 31 45-606


03EI5411B - Universität Siegen
  • Address:
  • Universität Siegen
    Chair of Energy and Environmental Process Engineering at the Institute for Energy Technology
    Paul-Bonatz-Str. 9 - 11
    57076 Siegen
  • Contact:
  • Prof. Dr.-Ing. habil. Wolfgang Krumm - project leader
    Telephone: +49 (0)271 740 2634

    Moritz Gebser - direct contact person
    Telephone: +49 (0)271 740 4624

03EI5411C - FEhS – Institut für Baustoff-Forschung e.V.

Associated partners

03EI5411 - SICON Germany
  • Address:
  • SICON Germany
    Vordere Insbach 26
    57271 Hilchenbach
  • Contact:
  • Heiner Guschall - project contact
    Telephone: +49 (0)2733 811760

Cooperation partners



Planned results:

  • Plant level: process, pilot plant, plant/system components
  • Concept level: plant concept
  • Data level: modelling
  • Market level: market-ready technology, market-ready components
  • Publications: scientific papers


The project focuses on energy-self-sufficient recovery of phosphates from sewage sludge. By means of the amendment of the Abfall-Klärschlammverordnung obliges sewage plant operators to recover phosphorus from wastewater. Dried sewage sludge is gasified to generate gas and coke. Coke originated from the gasification is burned in a bubbling fluidized bed reactor to enrich the resulting ashes with phosphorous. Afterwards the phosphorus is recovered by melting the ashes. Heat generated by the bubbling fluidized bed reactor is used for different steps of the process. The process should be realized by combining a new type of thermal process for sewage sludge treatment with melting the ashes.


The aim of this project is to develop a process for energy-self-sufficient phosphorous recovery. The product of this process is a phosphorous recycled material for agricultural use. The knowledge and data gained in this project should be used for an up-scaling of the plant which is used for thermal treatment of sewage sludge.


Entsorgungsbetrieb der Stadt Siegen

  • registration of mass flows and provision of residual materials
  • coordination of the project

Universität Siegen

  • characterization of residues and fuel design
  • operational tests
  • generation of a simulation model
  • planning of the up-scaling


  • Performance of vascular tests 
  • Proof of suitability as fertilizer


Entsorgungsbetrieb der Stadt Siegen

  • Collection of biomass flows and provision of data, provision of biomass, public relations

Universität Siegen

  • Characterisation of the biomasses, operation of the pilot plant, simulation of the process


  • Examination of the sewage sludge ash


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