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

Biomass furnace Power Heat

Project ID 03KB140

Sieb-OPTI - Optimized recovery of sieve residues from biowaste fermentation and composting plants

Fine screening of raw compost using a drum screen (Photo: Witzenhausen Institut)


  • 01.07.2018 – 30.06.2020


Witzenhausen-Institut für Abfall, Umwelt und Energie GmbH
Werner-Eisenberg-Weg 1
37213 Witzenhausen

Thomas Raussen – project leader
Telephone: +49 (0)5542-9380-15

Lennart Warning – direct contact person
Telephone: +49 (0)5542-9380-14


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Final report only available in german.


  1. In more than 50% of the organic goods treatment plants in Germany,> 10% of the plant input is disposed as sieve residues, whereby the disposal costs have risen sharply in recent years.
  2. High levels of foreign matter, as well as high levels of ash and harmful elements, are problematic for a legal classification of the sieve residues.
  3. Extensive systematic investigations (foreign matter content, grain size, ash content, etc.) on the subject of sieve residues were carried out on four practice plants with different treatment and processing technology, which can be of great benefit to the many plant operators in Germany.
  4. With regard to an economic assessment or an assessment of the climate relevance, the actual situation on site (system configuration, input material, etc.) is decisive. Two standard examples were considered in the project.
  5. Sensory techniques (NIR) or innovative combinations of existing techniques (e.g. air separator, stone trap) are available for optimized sieve residue processing.
  6. In addition to an optimized processing of organic material and organic material residues in a holistic treatment concept, the quality assurance of the input material (organic material) is of decisive importance.


The total project is focused on the issue of increasing sieve residues resulting from an enhanced pollution with foreign matters in biowaste fermentation and composting plants. The approach is to analyze existing disposal and recovery channels of sieve residues from biowaste in accordance with ecological, technical and legal aspects. Practice-appropriate recommendations for an optimized recovery are developed.


One objective of the project is a comprehensive status quo analysis of the disposal/recovery of sieve residues from biowaste in Germany. Appropriate recovery options will be analyzed in accordance with ecological, technical and legal aspects. Furthermore alternative and innovative recovery options will be tested. These recovery options will be evaluated with respect to their ecologic relevance as well as their impact on climate and resources.


  •  Status quo analysis of the disposal/recovery of sieve residues from biowaste
  •  Analysis of legal framework
  •  Analysis of appropriate recovery channels
  •  Optimization of treatment in practice
  •  Economic assessment
  •  Evaluation of impact on climate and resources
  •  Recommendations for practice


  • Material recovery & energy recovery
  • Potential analysis
  • Legal framework
  • Solid fuel
  • Municipal concepts


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