Feature: Japanese liquor producer explores circular economy by using sweet potatoes to generate electricity

Source: Xinhua| 2019-07-17 22:07:48|Editor: xuxin
Video PlayerClose

by Xinhua writers Ye Shan, Ma Caoran

TOKYO, July 17 (Xinhua) -- Kirishima Shochu Company, the largest producer of liquor in Japan, has been making efforts in exploring and demonstrating the development of circular economy by using the large amount of liquor waste from its production process for biomass power generation.

Located in the Miyazaki Prefecture on the Kyushu Island, Kirishima Shochu Company has a history of more than 100 years. Kirishima means "a foggy island" in Japanese.

The company uses sweet potatoes as its main raw material for making Japanese shochu, consuming up to 425 tons per day, according to Kirishima's introduction. The factory produces an average of 850 tons of brewing waste and 15 tons of sweet potato residue per day, with the brewing waste containing about 95 percent of water.

In the past, the company had to spend a lot of energy and money to deal with these wastes, which is a complicated process to be recycled by professional companies. In 2014, the shochu maker began to make full use of the waste generated in the production process to explore biomass power generation.

The staff first need to fill storage tanks with sweet potato residue and wine waste to be crushed and cooled. The wastes are then injected into biogas reactors to produce gas mainly made up of methane by the action of methane bacteria.

In this step, the solid-liquid separation step of the wastes is completed which generates solid sludge for centralized composting. The fertilizer from the compost will be returned to the crop fields and be used to grow sweet potatoes, the company's raw material for shochu making. The liquid waste produced in the process is then purified through sewage treatment plants and eventually discharged into sewers.

According to the company, it can produce 34,000 cubic meters of methane per day, which can be used by 22,000 households if it is all used for power generation.

Kirishima uses some of the gas for its own production, mainly as fuel for the distilling process, while the rest is used to generate electricity.

The company said that it currently generates 8.5 million KWH a year. In addition to the plant's own use, by selling surplus electricity to Kyushu electric power company, the shochu producer generates 240 million yen (2.22 million yen) of revenue every year.

Yoshikazu Higashimori, head of the waste treatment department of the company, said the project can make full use of its raw material and saves 3,000 tons of carbon emissions per year for the plant.

It not only solves the waste disposal problem that has plagued the company for a long time, but also brings the new business of power generation that has even generated some profits, he said.

Higashimori said that in the future, the company will continue to work hard to achieve the goal of zero emission.

In recognition of its contribution to the cause of environmental protection, the Japanese government awarded the shochu maker for realizing the goal of "environmentally symbiotic factory." In 2016, the company was awarded for its contribution to energy conservation and emission reduction by the Japanese government.

The company also opens its waste treatment facility to the public as the last stop of its factory tour to promote the awareness of environmental protection.