Recently municipal sewage and faculty-effluents containing considerable nitrogen and phosphate are flowing at river and coastal sea area, eutrophication-phenomenon is altered, and it is more and more advanced. As the method of municipal sewage-treatment is activated sludge process in this nation, only organic carbon and suspended solids are being removed, however, N and P-compds are not being entirely treated, eutrophication phen-omenon is more and more aggravated. From Jan. of 1996, N and P compounds are being controlled, in the nation however moderate treatment-system does not yet exist. Then, in this study, anaerobic -> anoxic -> aerobic process was used as N and P compounds removal system. P compds-removal is conducted as follows; at anaerobic tank, it is released, and it is intaked into bacteral cells at aerobic tank. N compds-removal is as follows; niitrification reaction is occured at aerobic tank, denitrification reaction is establised at anaerobic tank. In general, under the N-removal reaction, organic carbon and alkalinity are needed, in this research, without those chemicals, N and P-removal reaction is found possible.