Minamigamo, the largest wastewater treatment plant in the city, located just 300 m from the sea, was also devastated by the tsunami. Waves over 10.4 metres above normal sea level hit the pumping facility closest to the shore. All cars and ground equipment were washed away and the entire treatment plant was inundated. Fortunately, all plant employees escaped to the earthquake-proof administrative building – the only happy outcome of the disaster.

The Minamigamo plant, which had been treating 300 000 m3 of wastewater per day, came to a standstill. Rebuilding of the plant and full restoration of services is expected to take five years, at a cost of some USD 0.86 billion (JPY 70 billion).

As a result of our emergency work, there were not any major wastewater overflows in our city. We finished the survey of our 4500 km pipe thanks to help from other major cities of Japan. Our restoration has advanced steadily and we are ready to share the lessons of our experience with others.

Lessons learned

The disaster has highlighted the need for better risk, asset and crisis management in the future. It was evident that many water utilities in Japan had not implemented a risk management system, and that the concept of risk management was not fully understood.

Lessons learned from the recent Minamigamo experience must now be reflected in the water utility’s management system. Standardization is one of the most powerful tools to use in applying such lessons to an organization’s management system. In the case of the Minamigamo wastewater treatment plant, or indeed any water utility, the most urgent and appropriate standard is ISO 24511:2007, Activities relating to drinking water and wastewater services - Guidelines for the management of wastewater utilities and for the assessment of wastewater services.

ISO 24511 was developed by ISO/TC 224, Service activities relating to drinking water supply systems and wastewater systems – Quality criteria of the service and performance indicators. The International Standard provides guidelines for publicly and privately owned and operated wastewater facilities. It addresses wastewater systems in their entirety, and is applicable to systems at any level of development – e.g., pit latrines, on-site systems, networks and treatment facilities.

New crisis management system standard

The necessity of asset and risk management in the event of natural disasters is explicitly stated in the standard as one of the components of managing a wastewater utility. ISO/TC 224 continues to take a close interest in the asset and crisis management of water utilities, and is involved in new projects related to drinking water supply and wastewater systems.

In particular, the technical committee encourages broad implementation of management systems that enable water utilities to deal with disasters through standardization. For example, ISO/TC 224/ WG 7, Crisis management of water utilities, is currently drafting a crisis management system standard that is expected to provide valuable guidance in the event of a disaster.

Water authorities in Japan are contributing to the development of the new standard and to the effectiveness of a crisis management system for water utilities by drawing on the experience of the recent disaster. The aim is to improve the capability of the water industry to apply countermeasures against disasters through ISO and relevant standards.

Tetsuya Mizutani
Tetsuya Mizutani
Manager, Asset Management Strategy Office, Business Planning Section
Sewerage Management Department, Sendai City

Tetsuya Mizutani is Manager of the Asset Management Strategy Office in the Business Planning Section of the Sewerage Management Department of Sendai City, Japan. He heads a project to apply an asset management system to the city’s sewage works, and is a member of the national committee for ISO/TC 224, Service activities relating to drinking water supply systems and wastewater systems – Quality criteria of the service and performance indicators, WG 6, Asset management, and to ISO/PC 251, Asset management, WG 2, Requirements and applications guidelines.