Japan: Testing of Biogas Purification System at Sewage Treatment Plant

Japanese company Asahi Kasei and Kurashiki City (Okayama prefecture, Japan) intend to hold a trial to evaluate and demonstrate the performance of a biogas purification system at the Kojima sewage treatment plant in the city.

The installation of the system was scheduled for May this year. The start of operation is planned for the end of 2023.

Furthermore, the Mizushima Works of Asahi Kasei’s production center and Kurashiki City concluded a comprehensive partnership agreement for realizing carbon neutrality in society. Advancing the demonstration trial for decarbonization is one of the provisions of the partnership.

Biogas from, inter alia, sewage sludge and garbage consists of approximately 60 percent methane and 40 percent CO2. According to Asahi Kasei, the biogas purification system refines high-purity methane gas (biomethane) by removing CO2 from biogas utilizing the company’s newly developed adsorbent, K-GIS zeolite. “Unlike conventional adsorbents, which adsorb methane together with CO2, K-GIS zeolite adsorbs almost no methane,” the Japanese corporation gave account. “This enables the system to efficiently separate and recover high-purity methane while recovering high-purity CO2.” As reported, in Kurashiki City, electricity is generated using biogas derived from sewage sludge. The system would use a portion of this biogas for the demonstration trial.

“If biomethane production using the system is combined with carbon capture and utilization or storage (CCUS), the cycle would be carbon negative,” Asahi Kasei stated. The system’s commercialization is expected around 2025 or 2026 following additional trials in countries or regions where biogas purification is performed. “The technology will also be applied to CO2 separation and recovery from gases other than biogas.”


(Published in GLOBAL RECYCLING Magazine 2/2023, Page 44, Graphic: Asahi Kasei)