Abstract
We discussed the influence of the difference of the three evaluation method on the counting greenhouse gas emission from sewage treatment plant. We calculated the amount of CH4 and N2O by three method, 1st : IPCCs' guideline, 2nd : the guideline in Japan, and 3rd : the method including the direct and indirect emission of N2O, the emission of dissolved N2O through treatment water, and the direct emission of CH4. The amount of GHGs calculated by Japans' method was lower than that of GHGs calculated by IPCCs' method, even both were calculated based on the identical data. The difference of the results among IPCCs' method, Japans' method, mix method and D-mix method was mainly arised by the indirect emission of N2O, it was supposed that the indirect emission of N2O was important factor quantatively in GHGs calculation. The amount of the dissolved N2O in treated water was almost equal to that of the direct gas emission of N2O, so the dissolved N2O was supposed to be a potential source of N2O emission.
