Sewerage Bureau of Tokyo Metropolitan Government has launched new project in which dewatered sludge is turned into fuel charcoal and sold for thermal power generation plant. This project scheme is implemented for the first time in Japan. This project is expected to strongly promote the utilization of sewage sludge and the reduction of GHG.
Sewerage Bureau of Tokyo has promoted utilization of sewage sludge in order to contribute to realizing recycling-oriented society. In Tokyo, whole dewatered sludge is incinerated and ash is disposed of by ocean dumping or provided as raw materials to cement factory and so on. To enhance the contribution to environmental preservation, we has launched new project in which dewatered sludge is turned into carbonized material and sold as fuel for thermal power generation plant. This project scheme is implemented for the first time in Japan.
Reduction of Greenhouse gases (GHG) emission Sewerage Bureau of Tokyo is emitting 43% of GHG attributed to Tokyo Metropolitan Government’s activities. So Sewerage Bureau is greatly responsible for preventing global warming (Figure 1). Especially, GHG from sludge incineration occupies large portion, which should be mitigated (Figure 2).
Until now, Sewerage Bureau has utilized thermal content of wastewater or made effort to reduce energy consumption. In September 2004, Sewerage Bureau formulated “Earth Plan 2004” in order to carry out countermeasures against global warming willingly and actively. In this Plan, emission amount of GHG shall be reduced to 94% of 1990’s emission amount by fiscal 2009 (Figure 3). Sludge carbonization project is a quite effective project and bears 20% in total GHG emission reduction in the Plan.