| Title |
Effects of the Construction of Public Sewerage Systems on the Improvement of Water Quality : The Case of Large Cities in Japan |
| Abstract |
In this paper, attempts were made to analyze the effects of the construction of public sewerage systems on the water quality in public water areas and to evaluate the treatment efficiency with the inflow of industrial sewage in Japanese large cities. The findings of this study were as follows; 1. The water quality in the public water areas has gradually improved as with the increase in the treated-sewage ratio. 2. The treatment-efficiency has not decreased though the industrial sewage flow into sewage treatment plants. 3. The attainment rate of environmental standard does not improve proportional to the increase in the treated-sewage ratio of public sewerage systems since the 1980s. An increase in the amount of pollution load from the residential wastewater, prevents from increasing the attainment rate of environmental standard in the public water areas. This finding implies a need of designing the anti-pollution policies focused on the domestic sewage. |