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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!

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.

English-language brochure and map of the Sapporo Sewerage Science Museum.

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.

Exterior of the Sapporo Sewerage Science Museum

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!

Scientific children's area at the Sapporo Sewerage Science Museum.

Microorganisms! Wastewater conditions in which they thrive!

Scientific children's area at the Sapporo Sewerage Science Museum.

And some kawaii designs of Sapporo's site-specific manhole covers.

Kawaii site-specific manhole covers for Sapporo.

The Main Exhibit Hall

OK, finally paying attention to the museum guide and map, I went upstairs.

Overview of the Sapporo Sewerage Science Museum

Pipes! Dioramas!

Overview of the Sapporo Sewerage Science Museum

Detailed exhibits!

Overview of the Sapporo Sewerage Science Museum

Simulated pipes to walk through!

Simulated wastewater collection pipe.

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.

Simplified diorama of Sapporo.

I continued into the exhibits through a nicely simulated wastewater pipe system.

Simulated wastewater collection pipe.
Simulated wastewater collection pipe.

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.

Overview of wastewater processing.

Each section is introduced by a kawaii cartoon of a specialist. But that is followed by technology and science.

Equipment inspection specialist.
Actual equipment inspection specialists.

Inspection team examining equipment, checking the blower, injecting grease into the pump.

Water quality monitoring expert.

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.

Sapporo's custom manhole cover.

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.

Japanese cities' custom manhole cover designs.
Japanese cities' custom manhole cover designs.


Moving from metallurgy to microbiology, we're shown some of the microorganisms used to digest waste. Here are Carchesium and Rotaria.

Carchesium and rotaria microorganisms.

And, Lepadella and Macrobiotus, a genus of about 100 species of tardigrade, everyone's favorite nearly-indestructible microorganisms.

Lepadella and Macrobiotus microorganisms.
Sludge processing expert.

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.

Sludge treatment technology.

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.

Sludge treatment technology.
Sludge treatment technology.

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.

Sludge burning technology.

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.

Sludge burning technology.

Ash from the east sludge center in Shiro Ward, burned at 850 °C:

Ash burned at 850 ° C.

Ash from the west sludge center in Teine Ward, burned at 1100 °C:

Ash 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.

Inspecting sewer pipe interiors.

And, how they can clean pipes with pressurized water.

Cleaning sewer pipe interiors.

If all else fails, go down into the pipe and look at it.

In-person inspection of sewer pipes.

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.

Reduced bubble size for aeration saves 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.

Burning wastewater sludge to spin turbines, spin generators, and create electrical power.

Reconditioning Existing Pipes

The museum presented several different approaches for reconditioning old sewer pipes.

Technology for reconditioning old sewer pipes.

They had an 80-year-old pipe with a liner inserted for continued use.

Reconditioned 80-year-old sewer pipe.
Reconditioned 80-year-old sewer pipe.

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.

New system for reconditioning sewer pipes.
New system for reconditioning sewer pipes.
New system for reconditioning sewer pipes.

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.

Extracting energy from wastewater heat.

Finishing the Visit

This had been a very nice museum visit!

Osaka's Ebie Sewage Treatment Plant

Ōsaka 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.

Hallway leading to the toilets.

Very nice!

Men's toilets.

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.

Exterior of the Sapporo Sewerage Science Museum
Soseigawa Wastewater Treatment Plant.

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.

Soseigawa Wastewater Treatment Plant.
Soseigawa Wastewater Treatment Plant.

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.


Impressive HF and VHF ham radio antennas.