The other day, the Chuo-ku Tourism Association announced that it was recruiting a "Sewerage Infrastructure Tour", and since it was elected, I participated with my wife on December 14. Meet at Tachikawa Station on the day. 21 participants and the public relations staff of the Tokyo Metropolitan Sewerage Bureau also traveled by bus
. Go to Kitatama No. 2 Water Reclamation Center in Mazu Kunitachi City, go down about 11m by elevator and walk along the tunnel (about 1km) where communication pipes are laid to see 
the Asakawa Water Reclamation Center. Attach a pamphlet from the center and a photo
of the tunnel on the day. It is said that the diameter is 3.5m after construction using machines used for subway construction and tunnel excavation.
This is the director of the center who explained it.
The tunnel passes under the Tama River. The pipes on the left and right of the tunnel are connected to both water reclamation centers so that sewage can be sent to each other (backup when one is damaged). At the Asakawa Water Reclamation Center, we received an explanation of sewage treatment and saw the actual treatment equipment. In the facility, there is no odor, and it is confirmed that the sewage becomes clear water. It was really beautiful. It is released into the river in that state.
This is a photo of the lid of the sewage manhole. The real thing is not colored, but the pink cherry blossoms, yellow ginkgo leaves, and the surrounding area are represented by a black Yurikamome. (Everyone is a symbol of the city?)
I didn't notice until now, but if you walk with caution, you 
can see this manhole everywhere.
After that, we moved by bus and observed the construction
of a huge reservoir currently under construction. "Second Tagara River Trunk Line Part 2 Construction" Walk 18m and see a huge tunnel under construction. 40,000 cubic meters of rice (how many cups of 25m pool?) It is said that there is a water storage capacity. Please take a look at the photo. Concrete segments and steel segments are used properly, and curves and other areas are made of steel and finished with concrete later. Drilling work is underway at the end of this tunnel. The rails are used for trolleys to carry out excavated soil.
Both the Water Reclamation Center and the Tagara River Main Line are major civil engineering work. However, it is easy to study if you visit facilities for sewage treatment and flood control that are not very familiar in this way. The participant's throat was mentioned, but it was an "adult social studies tour". I hope you will join us once if you have the opportunity. The next time is January 12, but the number of applications seems to be four times. It seems that it was double this time.
