The biogas produced in the anaerobic digester at the wastewater treatment plant is fed in combination with H2 into the trickle bed reactor with immobilized microorganisms and upgraded to almost natural gas quality (CH4-concentration > 97 %). The pilot reactor is the largest of its kind in the world and provides important insights for future large-scale application. Afterwards Konrad Koch gave a guided tour through the wastewater treatment plant Garching.