In 2009 Christiaens Group and Biogas Anlagenbau Langenau (BAL) started a cooperation. BAL runs several dry anaerobic digestion facilities.
The Langenau Dry AD facility consists of 7 gas tight tunnels. The tunnels are filled by loader(1) after carefully mixing the different input materials and inoculum. Only 5-15% inoculum is required. After the doors are sealed, the waste is sprayed with percolate from the percolate tank.
The percolate, which is at approximately 40°C, distributes the gas producing micro organisms through the pile of waste. Besides biogas production in the tunnels there is also biogas production in the percolate tank. The produced biogas is analysed(2), cleaned and temporarily stored.
The biogas is combusted in one of the 3 180kWel CHP’s(3) to create electricity and heat. The electricity is fed into the grid and the heat is used for heating a swimming pool, drying wood chips and to keep the process at the right temperature.
After 28-35 days the compost is taken from the tunnel and stored outside to mature. The mature compost is used as soil improvement for agricultural use(4). Moreover, the effluent can be used as high quality fertilizer for agriculture. These results in optimally using the potential of organic waste.