Re: “Sewage system a danger in big earthquake,” Jan. 2.
The writer makes an inaccurate assumption that the structures and pipelines that will form part of the core-area sewage treatment system are going to fail catastrophically in the event of the “Big One,” releasing their contents into the environment.
The structures and pipelines that form part of the Core Area Wastewater Treatment Program will be designed to meet current earthquake-design standards. Unlike sewer pipes with unrestrained joints that are at risk of suffering extensive damage during an earthquake, these pipelines will either have restrained joints or fused joints to minimize the risk of failure.
This approach has been used for years on our major regional water-supply transmission pipelines. In addition, the control systems on the pressure pipelines will be designed to shut down automatically if a pipe failure occurs, and flexible couplings can be used between pipes and structures to minimize the risk of failure.
Professional engineers with appropriate credentials will design a sewage treatment system that meets the standards of a high-risk earthquake zone.
Jack Hull, P. Eng, MBA
Interim program director
Core Area Wastewater Treatment Program
