A consortium linked to the Karlsruhe Institute of Technology (KIT) has built a plant at the Mannheim wastewater treatment plant that cleans generated biogas and uses the resulting CO₂ to produce climate-neutral marine fuel using green hydrogen. https://theprogressplaybook.com/2025/03/25/new-wastewater-treatment-plant-uses-sewage-to-produce-climate-friendly-shipping-fuel/