Use of a canal as a temporary treatment plant with the cooperation of residents

After the earthquake, most of the seven sewage treatment plants in Kobe were restored relatively quickly. The biggest plant, in the eastern part of Kobe, however, completely stopped functioning.
It meant that untreated sewage had to be discharged into the ocean. On the day after the earthquake, the decision was made to utilize a nearby canal as a temporary treatment plant. Construction started, with understanding from the residents and members of the fishing industry. One of the main concerns was the bad odor problem.

Photo: A spot where sewage flows into the plant was damaged.

Photo: Damage to the plant


A few months later, winter turned to spring, and rising temperatures worsened the smell from the canal and began to affect the residents’ daily lives. While continuing sewage treatment in the canal, Mr. Hata and his colleagues kept in close contact with residents to report the restoration progress of the damaged plant. Four months after the earthquake, it was restored enough to be able to treat sewage again.

Restoration continued, and the riverside of the canal was redesigned as a promenade where people can enjoy walking or jogging. When the almond trees on the promenade are in bloom, a music concert is held, attracting up to 10,000 people every year.

Photo: The promenade with almond trees which bloom pink blossoms in spring, and a biotope with recycled treated water


Our bible: “Kobe Sewage System Future 2025”

The “Kobe Sewage Future 2025: Kobe Sewage System Long-term Master Plan” was established in 1994. Since then, Mr. Hata has implemented various projects such as networking of the sewage system, natural environment conservation activities, and contribution to city development by supplying treated water.

The master plan has three main concepts; “A sewage system which supports city development and citizens’ lifestyle”, “A sewage system which protects the environment”, and “A sewage system which works in harmony with residents”. In January 1996, it was revised using the lessons of the earthquake; including “disaster resistance” and “utilization in times of disasters”. These concepts make up our bible which has supported us for the last 20 years.

Photo: “Kobe Sewage Future 2025: Kobe Sewage System Long-term Master Plan”


Recycling treated water: streams where even fish can swim

In Kobe, treated water is used to water roadside trees and as water for flushing toilets, but it is also being recycled for streams where children can play and people can rest. Kobe City came up with the idea of making streams from treated water together with citizens. These streams can bring life to the city, and can also be used in case of emergency, something we learned from the large fires in the 1995 earthquake. A few years later, however, parents raised questions about the cleanliness of the streams: “Can we let our children play in water that was originally sewage?”

The big concern was how much the water should be sterilized for children to play in and for fish to swim in. If we added more chlorine, it would be more sanitary for children, but fish would not be able to swim in the water. In a discussion with residents and experts, a mother gave her opinion. She said, “Maybe we just have to teach our kids to wash their hands well after playing with water.” Everyone could understand her point, and it provided a good opportunity to think about the real issue at hand.

Photo: A stream made with the cooperation of the citizens, based on lessons learned from the earthquake


Kobe Biogas: the first practical application in Japan

Since 2008, “Kobe Biogas” has been used as an automotive fuel. It is produced by concentrating the sludge generated by the water treatment process. The Kobe Biogas project is the first in Japan to put biogas to practical use. After a joint study with a private company, Kobe Biogas is now used for city buses, as city gas, as well as to generate energy in the Kobe East Sewage Treatment Plant.

We joined theOsaka Gas Co., Ltd. Network, which has many users, in order to realize a stable supply of Kobe Biogas for automotive fuel, and to utilize it more effectively. Now, we supply our Biogas to more than 3,000 households.

Photo: Kobe Biogas Station in the East Treatment Plant: now refueling


A thick file

Mr. Hata showed us a thick file. The spine says, “To be kept indefinitely: If a severe earthquake happens anywhere, run to help with this file”.

Since sewage systems rarely suffer direct damage from natural disasters, many sewage officials are not accustomed to the process of assessing damage and submitting reports to the government. We made this file based on our experience in the Great Hanshin-Awaji Earthquake so that we can be ready at any time to run to help. When the tsunami hit northern Japan in 2011, we dispatched our staff to support their restoration efforts. I believe that it is our mission to keep on spreading our expertise.

Photo: File to be kept indefinitely: filled with documents necessary for damage assessment


Passing on Kobe’s expertise to the world

The East Sewage Treatment Plant, which suffered severe damage in the earthquake, is now drawing attention from other parts of Japan and overseas. About a thousand people visit the plant to inspect it every year.

It is essential that Kobe City use its experience to assume a leadership role in sewage system disaster response, and repay all those who helped us in our own restoration efforts.

Mr. Hata aims to pass on Kobe City’s know-how and expertise to the world. At the end of our interview, we asked him the roles that Kobe Sewage System should play.

We have two main roles. One is to keep the system running smoothly by replacing aged facilities in order to prevent malfunction. The other is to provide flood damage prevention. The number of sediment disaster is on the increase, and widespread floods have happened four times in Kobe’s urban areas recently. We must keep working on necessary measures to prevent natural disasters in cooperation with residents.

(Photographed by Natsumi Morimoto, interviewed and written by Kaori Nikaido and Aya Yamamori)