The EKaBio consortium carried out full‑scale experiments in a cascade plant located in the district of Aurich to optimise the operation of cascade systems for biogenic waste. The main scientific focus was the composting stage of the cascade, which is increasingly important because of tightening legal requirements such as the BioAbfV and the new total organic carbon (TOC) limit of 250 mg m⁻³ in the exhaust air set by the TA Luft. The project therefore investigated whether the composition of the rotte input could be altered to increase the share of solid biowaste and to add liquid biowaste while still meeting the new limits. In addition, the influence of external heat supply on the rotte process was examined.

Three substrate mixtures were defined. Variant I contained only biowaste and structural material, Variant II added solid biowaste, and Variant III incorporated both solid and liquid biowaste. The structural material proportion was kept constant in all cases. The mixtures were fed alternately into a rotte tunnel equipped with measurement instrumentation at two sites: a mechanised mixing plant in Anröchte and a passive mixing plant in Großefehn. The study measured substrate quality (density, foreign‑material content, moisture), emissions (volatile organic compounds, total organic carbon), process stability, and energy consumption. Specific electrical and thermal energy consumptions were quantified for each variant and compared to the baseline. The data, presented in Tables 13–18 of the report, show that the inclusion of liquid biowaste in Variant III reduced the specific electrical energy consumption relative to Variant I, while the thermal energy requirement was also lowered when external heat was supplied. Emission measurements indicated that the mechanised mixing process in Anröchte produced lower concentrations of VOCs and TOC in the exhaust air than the passive process in Großefehn, thereby improving compliance with the 250 mg m⁻³ limit. The study also demonstrated that the rotte process could be stabilised with the new substrate compositions, as evidenced by consistent temperature profiles and reduced cycle times.

The project employed Fourier‑Transform Infrared Spectroscopy (FTIR) in two mobile measurement containers to monitor the substrate composition in real time. The data obtained were used to calibrate the process control system and to provide a basis for future research questions that will be pursued by the individual partners in their respective expertise areas. The results are intended to be integrated into university curricula, ensuring that students receive up‑to‑date knowledge on cascade technology and environmental compliance.

EKaBio was a collaborative effort involving research institutes, industry partners, and local authorities. The consortium coordinated the design, execution, and analysis of the experiments, with each partner responsible for specific tasks such as substrate characterisation, process control, emissions monitoring, and energy accounting. The project ran over a period of several years, encompassing data collection from 2019 to 2022 and subsequent analysis. Funding was provided by a national research programme aimed at advancing sustainable waste management, reflecting the policy relevance of the work. The consortium’s findings contribute to the optimisation of cascade systems, offering a pathway to meet stricter environmental regulations while improving energy efficiency and resource recovery.