Taiheiyo Cement Corporation, Japan's largest cement manufacturer, has launched a project to recycle all waste discharged from Hidaka City (pop. 54,000, in Saitama Prefecture) by processing it into raw material for making cement at its Saitama plant.

In the process, household and general commercial waste collected in the city are taken to the plant and processed using aerobic fermentation, by aerating it for three days in a "waste recycling kiln" that has been converted from a cement kiln. After removing foreign substances that cannot be recycled, the rest is used as raw material for cement.

The main features of this process are the following:
1. Direct fermentation of waste eliminates the need for incinerators.
2. Gas generated during the fermentation process can be used as air for combustion in cement kilns.
3. The fermented and recycled waste used as raw material for cement emit no toxic substances such as dioxins, since they are fired at 1,450 degrees Celsius.
4. The process generates no secondary waste, such as incineration ash, eliminating the need for final disposal facilities.

Hidaka City estimates the amount of waste that could be processed this way at 14,800 tonnes per year (about 60 tonnes per day in operation). The cost paid to Taiheiyo Cement is 39,000 yen (about U.S. $317) per tonne, which is higher than the current cost it pays for waste incineration, but the city expects that the total costs will be reduced, as the new system can eliminate the need for incineration plants, as well as final disposal facilities for incineration ashes.


http://www.taiheiyo-cement.co.jp/english/index.html

Posted: 2002/12/30 06:12:16 AM
Japanese version

TAG Chemicals , Eco-product/Business , Local government , Manufacturing industry , Material reduction