TMG Bureau of Sewerage Develops Three New Technologies to Contribute to Mitigate Global Warming

The Tokyo Metropolitan Government Bureau of Sewerage announced on June 29, 2010, that it has jointly developed with private companies, three new technologies that will contribute to mitigating the effects of climate change. The technologies are: (1) a fluidized-bed incinerator with a turbocharger; (2) an efficient dehydration system for sewage sludge; and (3) a fiber-optic water-level detecting system.

When burning the sludge generated during wastewater treatment process, large amount of greenhouse gases such as CO2 or nitrous oxide (N2O) are produced. In the fluidized-bed incinerator with a turbocharger, the turbocharger is driven by the exhaust gas to send compressed air into the incinerator with no need for a fan. Thus, the incinerator is pressurized and burns the sludge at 870 degrees Celsius, which is higher than the conventional temperature of 850 degrees Celsius. This helps to accelerate thermal decomposition of N2O. The incinerator is also smaller, allowing for lower fuel use.

A verification test for the new incinerator showed that N2O emissions are reduced by 50 percent or more, CO2 emissions are reduced by 10 percent or more due to reduced fuel use, and by 40 percent or more due to reduced power use, as compared to existing devices. Based on the results of the test, the Bureau decided to put this design into practical use and plans to start introducing new incinerators. The test was jointly carried out by the Bureau, and Tsukishima Kikai Co. and Sanki Engineering Co.

The technology to efficiently dehydrate sludge uses image analysis to obtain stable dehydration. The fiber-optic water-level detecting system uses a low-cost detector and requires no power source.

The Tokyo Metropolitan Government Bureau of Sewerage official website
http://www.gesui.metro.tokyo.jp/english/english.htm

Posted: 2010/09/27 06:00:15 AM