The FermKomp project, funded under the German federal code 03KB100A‑C and coordinated by the German Federal Institute for Water, Environment and Agriculture (DBFZ), ran from 2016 to 2018 and culminated in a final report dated 5 October 2018. Its aim was to combine dry anaerobic fermentation of household and industrial bio‑waste with a subsequent aerobic composting stage, thereby improving energy recovery and reducing greenhouse‑gas emissions compared with conventional composting alone. The project was carried out in close collaboration with GICON, a small‑to‑medium enterprise specialising in solid‑state fermentation, and with the Canadian research partner AITF, which supplied advanced substrate‑characterisation techniques that had been developed in earlier DBFZ projects.

Technically, the work was organised into four work packages. The first package established the project’s overall coordination and defined the research objectives. The second package focused on characterising substrate and structure‑material mixtures. Standardised methods already in use at DBFZ—such as particle‑size distribution, moisture‑capacity measurements, and bulk‑density determinations—were applied to a range of household waste streams and to mixtures of waste with bulking agents. These characterisations revealed that a well‑structured substrate with sufficient porosity and moisture capacity is essential for effective percolation of liquids in the anaerobic phase and for adequate oxygen penetration during the aerobic composting phase. The third package investigated the efficiency of solid fermentation. A laboratory‑scale reactor was operated to study the influence of structural properties and percolation regimes on biodegradation. Statistical analysis of the lab trials showed that substrates with higher porosity and lower bulk density produced methane yields up to 20 % higher than poorly structured mixtures, while the temperature profiles indicated more stable thermophilic conditions. The laboratory results were then scaled up to a pilot‑scale container system operated at GICON’s facility. The large‑scale tests confirmed the laboratory findings: improved substrate structure led to a 15 % increase in biogas production and a 10 % reduction in the time required to reach stable composting temperatures. The fourth package measured greenhouse‑gas emissions from the composting stage. Existing DBFZ emission‑measurement protocols—based on open‑path laser spectroscopy and infrared imaging—were employed to quantify methane, carbon dioxide, and nitrous oxide fluxes. The measurements demonstrated that the integrated dry‑fermentation/composting process reduced net methane emissions by roughly 30 % compared with a conventional composting route, while carbon‑dioxide emissions remained comparable. These results were interpreted in the context of the German national inventory of agricultural biogas production and were used to refine life‑cycle assessment models for bio‑waste treatment.

The collaboration structure was clearly defined: DBFZ served as the project coordinator and provided the core expertise in dry fermentation and emissions monitoring; GICON supplied the pilot plant, operational knowledge of solid‑state fermentation, and facilitated the transfer of results to industrial practice; AITF contributed advanced analytical techniques for substrate characterisation and helped adapt them to the project’s specific needs. The project’s funding, provided by the German federal Ministry of Food, Agriculture and Consumer Protection through the Fachagentur Nachwachsende Rohstoffe, covered the costs of equipment, personnel, and field trials. The final report, encompassing 17 pages plus annexes, documents the technical achievements, performance data, and the practical implications for scaling up bio‑waste treatment facilities.