Methane Gas Emissions from Waste Landfills - 1997 to 2020s

Methane Gas Emissions from Waste Landfills - 1997 to 2020s

In 1997, the problem of large amounts of methane gas emitted from the decomposition of organic waste in Japan's urban waste landfills was identified as a contributing factor to global warming. In particular, it was reported that about 500,000 tons of methane gas was being released into the atmosphere each year untreated at the former Yumenoshima landfill in Koto-ku, Tokyo. At that time, the installation of gas recovery facilities had not progressed nationwide and was a major factor in increasing air pollution and greenhouse gas emissions.

Some municipalities have made progress in addressing this issue. In Isogo Ward, Yokohama City, a project was launched to collect methane gas generated at a landfill site and use it to generate electricity at public facilities and factories. In Konohana-ku, Osaka City, Osaka Gas Co., Ltd. has developed a technology to supply methane gas as city gas, and has achieved a gas recovery rate of over 80%. In Kawasaki City, Kawasaki Heavy Industries, Ltd. introduced a power generation system that utilizes the residual heat from a waste incineration facility, successfully reducing landfill waste by approximately 50,000 tons per year.

2010s: Technological Evolution and Challenges
In the 2010s, as environmental technologies advanced, facilities were developed nationwide to meet the demand for higher methane gas recovery rates from landfills. For example, in Kitakyushu City, a model case was constructed to recover methane gas generated from waste and use it as an energy source in an industrial area. On the other hand, the introduction of facilities at former landfills in rural areas lagged behind, and more than 10,000 tons of methane was released annually uncollected at a former landfill in Tomakomai, Hokkaido.

The 2020s: Current Status and Prospects
In the 2020s, methane gas emissions from landfills remain an important issue in the fight against global warming. In Koto-ku, Tokyo, approximately 500,000 tons of methane is still emitted annually, and there is an urgent need to improve the recovery rate. In the Yokohama City project, a system by Ebara Environmental Plant Co. Osaka City and Kawasaki City are also making progress in the efficient use of recovered gas through the introduction of new technologies.

However, the national average gas recovery rate is only about 30%, leaving room for improvement at former landfill sites in rural areas. The government has set a goal of installing recovery facilities at landfills nationwide, and companies such as Mitsubishi Heavy Industries and Hitachi Zosen are accelerating technological development. Through these efforts, the government aims to reduce methane gas emissions and reuse energy, as well as promote sustainable management of landfill sites.

The reduction of methane gas emissions contributes not only to the prevention of global warming but also to more efficient energy use, and is positioned as an important pillar of future environmental policy.