National

Kagawa city’s cutting-edge waste composting plant sparks interest from across Japan

Kyodo

A new waste disposal plant in Shikoku that uses a cost-effective, environmentally friendly composting method is drawing interest from other municipalities needing to replace aging waste disposal facilities.

Located in a mountainous area of Mitoyo, Kagawa Prefecture, the Biomass Recycling Center Mitoyo went into operation in April. It neither resembles a typical waste plant nor emits unpleasant odors or fumes.

The center, with 4,000 sq. meters of floor space, is Japan’s first waste disposal facility based on technology called “tunnel composting.” The method uses microorganisms to decompose waste and produce fuel.

“The greatest merit of this plant is that it recycles waste into fuel instead of incinerating it,” said Hideyuki Kamakura, the center’s director.

Since the technology can cut carbon dioxide emissions, it is widely used in environmentally conscious European nations.

Waste collected from households and businesses is stored for 17 days in six enclosed fermentation tanks called “bio-tunnels,” where temperatures are controlled by computer.

There, waste is biologically decomposed, dried and divided into organic matter, paper and plastic.

The organic waste is returned to the tanks for further fermentation. The dried paper and plastic is compressed and formed into solid fuel.

The fuel, about one-third the price of coal, is used in a boiler at a paper manufacturer in Shikokuchuo, Ehime Prefecture.

The recycling center is operated by Eco Master, a Mitoyo-based company set up by two solid-fuel manufacturers in Kagawa.

The Mitoyo Municipal Government has signed a 20-year consignment contract for the recycling system with Eco Master.

“A great thing about this contract is that we don’t have to shoulder the construction cost worth about ¥1.6 billion,” said Hirotomi Ochi, head of the city’s environmental sanitation division.

The disposal center has drawn the attention of municipalities across the nation since its establishment.

After visiting the center recently, a Mie Prefecture official described the facility as “very innovative and interesting,” praising its compact design and odor-free operation.

But an official from Taka, Hyogo Prefecture, pointed to the main challenge to adopting the system, which is securing a sufficient number of customers to purchase the fuel on a steady basis.

“We can’t think of introducing this type of facility in our town in the immediate future,” the official said.

Experts also pointed out that the facility’s waste processing capacity is less than that of incinerators, making its use in densely populated areas difficult.

But the center’s Kamakura said the fuel produced by this system can be used in coal-fired power plants, among other facilities.

“Waste incinerators in many municipalities are aging and need to be rebuilt soon,” he said. “I hope these municipalities will adopt our biomass center and the method will spread across Japan.”