• Kyodo


The Yokosuka Municipal Government is undertaking an experimental project in which garbage trucks will be powered in part by methane gas released when microorganisms break down waste.

According to municipal officials, this is the first such city-level attempt in Japan.

The city hopes to determine in August whether methane gas can be used to power the vehicles on a full-scale basis, the officials said.

The project entails placing biodegradable garbage in a tank with microorganisms so it can ferment. Of the gases released in the process, methane is refined and concentrated. Propane gas is then added to turn it into fuel.

If the process can be put to practical use, the amount of garbage that will have to be burned can be reduced by some 40 percent, officials said, adding that the amount of nitrogen oxide — a main source of air pollution — released by garbage trucks powered by this gas is 90 percent lower than in emissions from diesel vehicles.

At present, 81 percent of the city’s garbage is burned, while 13 percent is recycled and 5 percent is taken to landfills.

The city stepped up efforts to cut down on garbage and find better uses for it in fiscal 2001, when it joined forces with Sumitomo Heavy Industries Ltd. to study the issue.

Since the end of January, two of the city’s fleet of about 80 garbage trucks have been running on the bio-gas produced from the garbage.

Yokosuka officials said they hope to have 14 trucks running on environment-friendly fuels, including the bio-gas and natural gas, instead of diesel fuel, by the end of next March.

While there have been many experimental projects that attempt to use garbage as a viable resource, they usually focus on the recycling of raw garbage from restaurants and school-lunch facilities, according to the city. In contrast, Yokosuka’s project deals with burnable household refuse from which raw garbage has not been separated.

The city began building a plant to undertake the bio-gas experiment last May, with operations beginning last fall. All experiments are expected to be concluded by fiscal 2005, after which the plant will be torn down, according to the city.