Present State and Future Direction of Countermeasures for Pollution from Domestic Wastewater in Japan

Abstract

Japan is poorly provided with sewerage facilities especially in non-urban areas. Of domestic wastewater not discharged into the sewage system only night soil is treated, and the remaining domestic wastewater (grey water) is discharged untreated into public water bodies. Regarding the current water pollution load, the proportion of domestic wastewater, especially that of grey water, is increasing. It is not clear, however, who is legally responsible for grey water, and there is little interest in treatment of such grey water. Thus, the development of domestic wastewater pollution countermeasures will be an important task. This paper classifies the systems popularly used in Japan to treat domestic wastewater into several types, and describes the administrative regulations, and Government and other assistance, relating to them. Also, some promising systems for the treatment of domestic wastewater are presented as examples. Finally, future policies on domestic wastewater pollution countermeasures are discussed.