Sapporo Sewerage Science Museum
My Visit to the Sapporo Sewerage Science Museum
Sapporo, Japan, has an excellent museum
explaining their wastewater collection and treatment,
and how they maintain and update their system.
Much of it appears at first glance
as if it were aimed at kids,
but there is a lot of science here.
And that's good for the kids!
We'll see some microbiology
and thermodynamics.
There's civil engineering design and urban planning.
And I'll try to work in a little electromagnetics.
Of course I visited the museum
when I was in Sapporo!
Visiting
Japan
No, I went to Japan with
no
idea that the museum existed.
Sorry about destroying the glamorous image of
the Toilet Guru impulsively jetting half-way around the world
just to visit a newly discovered sewer museum...
A poster at the Sapporo Clock Tower downtown
had tipped me off about its existence.
To get to the museum,
ride the Namboku Line of the subway
to its north end at Asabu Station
and then walk for about fifteen minutes.
Here's the entrance. There were no cars in the parking area out front. I had arrived from behind, and the staff-only parking area in the back was also empty. It seemed as if no one was there, but it was open. They're open 0930-1700 daily except closed on Mondays, a pattern of museums world-wide. March up to the door and reach out to touch the pad, and it will slide open.
A woman came out to the Information Desk after I stepped into the lobby. She pointed me to the English museum guide, seen above.
The ground floor has a nice children's activity area. I wandered into it because I had not yet consulted the guide. When in Japan I blunder around like ゴジラ or Gojira, so that was par for the course. But it let me see that even the children-only part had good science!
Microorganisms! Wastewater conditions in which they thrive!
And some kawaii designs of Sapporo's site-specific manhole covers.
The Main Exhibit Hall
OK, finally paying attention to the museum guide and map, I went upstairs.
Pipes! Dioramas!
Detailed exhibits!
Simulated pipes to walk through!
The large building with the tall tower at the center of the diorama is Sapporo Station. I'm looking from the northeast to the southwest. There are the JR rail lines running from upper right to lower left, east-west through Sapporo Station. To the north, to the right in this map, is the Sapporo Sewerage Science Museum with its arched roof. OK, this is a simplified notional diorama, the museum is five and a half kilometers north of the train station. But this is good, it works on my Gojira-like level.
I continued into the exhibits through a nicely simulated wastewater pipe system.
There is some English in the museum displays, but not much. The English-language guide provides a little more. I used the Google Translate app on my phone, putting it in Camera mode and reading the displays through that.
Each section is introduced by a kawaii cartoon of a specialist. But that is followed by technology and science.
Inspection team examining equipment, checking the blower, injecting grease into the pump.
Manhole Covers
Many cities in Japan have custom manhole covers. Sapporo's shows the city's late 19th century Clock Tower and the salmon of Hokkaido, Japan's large northern island. And there's Kurin-chan, the mascot of the Sapporo City Sewerage system. This is Japan, everything has a kawaii mascot.
The text above the city-specific manhole cover explains a recent nation-wide redesign. Welcome to Japan, where what seems to be a children's museum quickly veers into metallurgy:
Conventional manhole cover (flat type)
This is a type where the lid is placed on a frame and the weight of the lid itself prevents it from flying off. There is a gap between the lid and the frame, so when a car drives over it, the lid moves and makes rattling noises.
Additionally, since it does not have a locking function, anyone could open it for illegal dumping. Or, heavy rain could displace it as water overflows from the manhole. Swelling ice could cause it to lift or shift.
The material used is gray cast iron (FC), which is prone to cracking when objects hit or bend it. For this reason, it was made thicker to prevent it from cracking, making it very heavy (approximately 80 kg) and difficult to open and close.
New manhole cover (gradient type)
The lid and frame are tapered so that they fit tightly together without any gaps, so the lid won't move or make rattling noises even when a car runs over it.
It also has a locking function, so you cannot open the lid without using a special key. Even after a heavy rain, the lid no longer moves out of place.
The material used is spheroidal graphite cast iron (FCD), which is resistant to cracking even if it is bumped by objects or bent. As a result, the lid can be made lighter (approximately 34kg to 45kg), making it easier to open and close than before.
As I said, Japanese cities have their own custom manhole cover designs. A national guide is available.
Microbiology
Moving from metallurgy to microbiology, we're shown some of the microorganisms used to digest waste. Here are Carchesium and Rotaria.
And, Lepadella and Macrobiotus, a genus of about 100 species of tardigrade, everyone's favorite nearly-indestructible microorganisms.
Sludge Processing
Then it moves into sludge treatment, something a friend of mine was involved in at the Hyperion wastewater treatment plant in Los Angeles.
Most of the water is removed through a series of processing stages. The resulting dry sludge is then burned, with an ash-like final residue.
Sapporo's East sludge treatment center in Shiro Ward burns sludge at 850 °C. The West sludge treatment center in Teine Ward uses a stepped furnace that burns sludge at 1100 °C.
Pictures of the burners above samples of the results. At left is the exhaust gas treatment to remove toxic components from the gas emitted during combustion.
Ash from the east sludge center in Shiro Ward, burned at 850 °C:
Ash from the west sludge center in Teine Ward, burned at 1100 °C:
Pipe Inspection and Cleaning
The Sapparo sewerage system has 8,300 kilometers of pipe, that's a lot to inspect and maintain. They show how they send small crawlers into the pipes with TV cameras.
And, how they can clean pipes with pressurized water.
If all else fails, go down into the pipe and look at it.
Saving and Extracting Energy
A section explained how to save energy. Smaller bubbles in the aeration process transfers more oxygen into solution with less energy.
And, in the most part that most interested me, how heat from the burning sludge can generate steam, which drives a turbine, spinning a generator and generating electrical power that is used to run the plant.
Reconditioning Existing Pipes
The museum presented several different approaches for reconditioning old sewer pipes.
They had an 80-year-old pipe with a liner inserted for continued use.
They have developed a new system, in which they feed plastic material off a reel on the truck on the street and create a new helical lining for the pipe.
Heat Transfer
Another exhibit had to do with extracting energy from the difference between ambient air temperature in Sapporo (quite cold through the winter!) and the wastewater temperature.
Finishing the Visit
This had been a very nice museum visit!
Osaka's Ebie Sewage Treatment PlantŌsaka had once had wastewater treatment museum at their Ebie Sewage Treatment Plant, but when I visited in 2018 it had been closed for some time. Hopefully this one will succeed.
And to think that I learned of of this from a poster at what most people would consider a much more mainstream tourist attraction.
I wanted to use the bathroom before heading back downtown. And, well, you know, photograph it.
Very nice!
The museum is along Sosei-gawa or the Sosei River, a heavily managed and re-routed waterway draining Sapporo toward the north into the Ishikara River and Ishikara Bay, and the Sea of Japan.
Just south of the cluster of buildings housing the museum and some sewer department offices, between it and the city baseball stadium, is the Soseigawa Wastewater Treatment Plant.
Radio
Along the walk between the subway station and the museum, I was impressed by this array of amateur radio antennas.
The large horizontally polarized Yagi-Uda beam has, I believe, one element for the 30m or 10.1 MHz band (thus a rotating dipole), and multiple elements for the higher 20/15/10m or 14/21/28 MHz bands.
Above that are two VHF beams fed as a pair for the 2m or 146 MHz band.
Nice!
