Urban Circulation, Reviving Sludge - Sewage Sludge Recycling in Tokyo in the 1990s - March 1998

Urban Circulation, Reviving Sludge - Sewage Sludge Recycling in Tokyo in the 1990s - March 1998

Recycling of sewage sludge is being promoted in Tokyo, and the Nanbu Sludge Plant in Jonanjima, Ota Ward, plays a central role in this effort. At this facility, various efforts are being made to make effective use of sewage sludge.

**Making Metro Bricks**.
The Nanbu Sludge Plant manufactures "Metro Bricks," compacted and calcined blocks made from incinerated ash of sewage sludge. These bricks are highly durable and are used as paving material for sidewalks, plazas, and parks. 900,000 units are produced annually and supplied to public utilities.

**Reuse as Cement Raw Material**.
In April 1997, the Tokyo Metropolitan Government began a plan to reuse 10,000 tons of incinerated sludge ash annually as a raw material for cement. This initiative is expected to provide companies with free cement feedstock and economic benefits.

**Conversion of Sludge into Fuel**.
The organic content of sewage sludge is also being utilized as fuel. By removing water from dewatered cake and creating a dried cake, a fuel with a calorific value comparable to low-grade coal can be obtained. This fuel is used to generate electricity in the Southern Sludge Plant.

**Related Information**.
- The Tokyo Metropolitan Government has been working to convert sewage sludge into a resource since the late 1965's, and has conducted various studies and developments.
- The Tokyo Metropolitan Government's Bureau of Sewerage's Environmental Report introduces its efforts to convert sewage sludge into a resource.
- The history of Tokyo Metropolitan Sewerage Service Co. (TGS) states that TGS was commissioned to operate and manage the lightweight fine granulation facility at the Southern Sludge Plant in 1996, and that it began operating the Seijo Parking Lot in 1998.