Smart use of thermal energy.
The ZAK composting facility in Kempten-Schlatt processes around 18,000 tonnes of biowaste and green waste each year into high-quality compost bearing the RAL quality seal. An integrated DRANCO anaerobic digestion stage produces approximately 6,100 m³ of biogas per day, which is converted into electricity and heat in three combined heat and power (CHP) units. The plant generates about 4.8 million kWh of electricity annually—enough to supply roughly 1,920 households—as well as 3.9 million kWh of heat. Part of the heat is used on site, while most of it heats neighboring greenhouses and corresponds to the demand of around 480 households. As a result, approximately 3,000 tonnes of CO₂ emissions and large quantities of fossil fuels are saved each year.
The biowaste is delivered, pre-treated, shredded, and screened before being processed in the digestion stage under controlled conditions. Biogas is produced in the DRANCO digester, while the digestate is mechanically dewatered and sent on for further composting. The digestate is dried and post-composted over several weeks before being screened and stored in the finishing stage. The exhaust air is treated by wet scrubbing and biofilters, removing around 95% of odor-causing substances.
Overall, the facility combines high-quality compost production with efficient energy generation, thereby contributing to climate protection, economic efficiency, and regional energy supply security.
