The rapidly aging population is creating business opportunities for manufacturing companies that have found a way to utilize tons of used paper diapers.

Determining that the bulk of diapers disposed of by hospitals and nursing homes were being sent to incineration plants, Super Faiths Inc. of Tokyo developed a machine to turn used diapers into solid fuel.

The device, called the SFD system, is capable of crushing, drying and sterilizing used diapers and converting them into bacteria-free pellets. The process takes one day. According to Super Faiths, the pellets serve as an excellent fuel for biomass boilers and stoves.

One of the early adopters is a hospital in Machida, Tokyo, that has installed the machine on its grounds. Other organizations, including a local government in Hokkaido, are considering adopting it.

Another company, Total Care System Co. of Fukuoka, has established a way of dissolving diapers in a special solution and turning them into pulp and plastic for use as a construction material and as solid fuel.

Total Care System has built a dedicated disposal plant in Omuta, Fukuoka Prefecture, and has been processing about 14 tons of used diapers daily. The diapers are collected from hospitals and welfare facilities in Kagoshima Prefecture.

The company is now collecting used diapers from households on a trial basis in cooperation with a number of local governments, such as the town of Oki, Fukuoka Prefecture.

Given Japan's low birthrate and the rising proportion of elderly, the number of people aged 65 and older is expected to total 28 million and account for 22.5 percent of the population this year, according to the National Institute of Population and Social Security Research.