In response to the road collapse incident in Saitama Prefecture in January, the city of Kobe held a special press conference to announce the city’s measures taken following the accident. The collapse was caused by damage to the sewer system, prompting Saitama Prefecture to urge approximately 1.2 million residents to refrain from using the sewer system for activities such as laundry and bathing.
The incident revealed that corrosion of the sewer system was a contributing factor, with reports indicating the presence of a sewage pipe installed in 1983 at a depth of approximately 10 meters. While Kobe City does not have facilities identified as “inspection targets” by the Ministry of Land, Infrastructure, Transport and Tourism, it does have large sewage pipes with a maximum diameter of 3 meters. Consequently, the city independently conducted emergency inspections on concrete pipes with a diameter of over 2 meters, covering around 16.9 kilometers, susceptible to corrosion from hydrogen sulfide.
From January 30 to 31, visual inspections of the roads were conducted, followed by internal inspections of manholes from February 3 to 7. Ongoing road cavity surveys are scheduled to continue until the end of February, utilizing advanced technologies such as floating cameras to ensure the safety and security of residents.
The city of Kobe operates a unique “sewer network system” connecting five treatment plants, drawing on the experience and lessons learned from the Great Hanshin-Awaji Earthquake. The city’s sewage network links treatment plants including the Suma, Nishi, Higashinada, Suzurandai, and Chubu treatment plants, facilitating one-way sewage flow from the elevated Suzurandai plant to the other treatment plants, while the three plants on the seaside can mutually exchange and treat sewage.
By connecting treatment plants with large-diameter sewer pipes, the network system allows the redirection of sewage to alternative treatment plants in case of operational failure at one plant. This system not only ensures resilience during disasters but also enables stable sewage treatment during plant renovations or maintenance.
Ramesh Khatri, a representative of Kansai Nepal News, commented that Kobe City’s proactive approach in conducting regular inspections and maintenance of sewage pipelines, particularly in high-risk areas for hydrogen sulfide, demonstrates a commitment to ensuring the safety and functionality of the city’s sewer system. Khatri also highlighted the importance of leveraging technology and collaborative efforts to uphold the standards of infrastructure maintenance and disaster preparedness.
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Author: MAYA | HARUTO
Posted at: February 10, 2025 7:00 pm
