Status Quo and Problems of Sewer Pipes Rehabilitation Methods in Japan

The functions of municipal sewerage systems can be completely fulfilled by the appropriate daily operation and maintenance of sewers, pumping stations and wastewater treatment facilities. In the Japanese large cities that started their sewerage construction at an early stage, more than 7,000 km of sewer pipes have passed the end of their 50 years service life. In addition, some parts of sewer pipes, that have not reached their service life yet, have already had severe deterioration and damage. Therefore, the amount of the annual rehabilitation and point repair of sewer pipes has been increasing every year.The open cut method, in general, cannot be adopted for the rehabilitation of old deteriorated sewer pipes due to the heavy traffics and the other various underground laid objects. In those circumstances, the importance of pipe rehabilitation methods technology has been well recognized. Nevertheless, there are many problems still to be solved in the construction management and quality control for the pipe rehabilitation methods technology, since there is various rehabilitation methods proposed and the different materials used in each method, and the liner pipes have to be formed in the existing sewer pipes. Therefore, the drawing up of specific manuals for the pipe rehabilitation methods construction management and quality management are widely requested in Japan.The Japan Institute of Wastewater Engineering Technology has started the research to study the status quo of construction management and quality control in each city and enterprise that carried out the sewer pipe rehabilitation methods, and to draw up the technical report. In this presentation, the standard requirements of liner pipes and the standard criteria in terms of those construction management and quality control are reported, and the some problems are discussed to evaluate and analyze the status quo study.