Silicon Valley Clean Water, the joint powers authority which operates the treatment facility out in Redwood Shores which handles wastewater from Belmont, San Carlos, Redwood City, Atherton and Menlo Park, is in the midst of a multi-year, multi-hundred-million-dollar maintenance/enhancement project.
As part of that project they are building a new line which will pump wastewater from where the various feeder lines come together near San Carlos Airport out to the treatment facility. This involves excavating a several mile long tunnel about 60 feet under the ground.
The technology they’re using to do this is similar to what’s used to build subway tunnels: a machine which bores its way underground.
It’s a very impressive machine, and quite large. Click on the thumbnails below to see what some of the major parts look like:
Here’s a video animation of the boring process you might enjoy: