Meet McMurdo: Waste Water Treatment Facility

Meet McMurdo: Waste Water Treatment Facility
Meet McMurdo: Waste Water Treatment Facility. Photo courtesy of Alex Eilers.

Here in McMurdo, we try to disturb the environment as little as possible. That wasn’t always the case. Up until 1981, people in Antarctica would dump their waste right into the ocean. The waters were becoming polluted; so many countries came together and decided to no longer allow dumping in Antarctica’s waters.

However, they did not stop dumping human waste into the ocean. And when I say human waste, I’m talking about the gross stuff. Why would that be bad for the environment?

Human waste is full of phosphorous and nitrogen, which, in large quantities, could be harmful to the ocean’s environment. These are essentially the same ingredients as those in fertilizer and will over-fertilize any vegetation in the water. The vegetation grows at a rapid rate, using up all of the oxygen in the water, creating what is known as a ‘dead zone.’ Because of this lack of oxygen, organisms (like fish) will either leave the area or die. There is also, needless to say, lots of bacteria in human waste that does not need to get into our oceans!

Waste Water Treatment Facility building
This is where the action happens, it the Waste Water Treatment Facility building. Photo Credit: Alan Light.

Credit: Alan Light

Finally in 2003, McMurdo’s Waste Water Treatment Facility was built, which cleans all gray water (waste water from showers, sinks, etc.) and black water (water from toilets), so that it can be safely released into the ocean.

How do you clean this nasty water?

I had no idea! So, I decided to take a tour of the Waste Water Treatment Facility to find out. Now, I have to admit, I was a bit nervous that it was going to smell bad, but my curiosity overcame my fear!

And to my surprise, when I walked into the building, I wasn’t greeted by an unpleasant smell, only a bunch of tanks filled with water! I soon learned that all of these tanks have a different purpose. The tanks make a series of ‘trains’ that the waste will pass through. During the summer, when there are more people in McMurdo, they use 2 or 3 trains to clean all of the waste. In the winter, only 1 train is needed.

Let’s hop on the train!

First, all of the water must go through the ‘Muffin Monster.’ This machine is basically a macerator; it breaks up any toilet paper and large chunks. Don’t ask about the large chunks.

Muffin Monster
And here it is... the 'Muffin Monster.' Photo courtesy of Yubecca Bragg.

After the Muffin Monster, the water passes through a bar screen to further remove any large pieces.

Bar screen
The bar screen. Photo courtesy of Yubecca Bragg.

Even though most of the solids are gone, the water is still very dirty. Guess who does the cleaning? I’ll give you a hint: it’s not the waste water operators!


The cleaning is done by bugs! That’s right! And guess where many these bugs come from? From our bodies! There are about 100 trillion micro-organisms living in your intestines, and they are also present in your waste. These bugs will feed off of the sludge and clean it on their own, but it’s the Waste Water Treatment Facility operators’ job to speed this process along. The team is constantly monitoring the bugs. They pull samples of the sludge every day just to check out these bugs!

Main basin
One of the main basins in the facility. Photo courtesy of Yubecca Bragg.


One of the last tanks that the water will flow into is the Final Clarifier. It’s here that the final settling happens: the clean water floats to the top while any leftover solids will sink to the bottom. The Final Clarifier then allows the clean water to flow into the UV (ultra violet) bank. Here it gets disinfected by a UV light. All of the solids will stay behind.

Clarity of water
Looking better! Photo courtesy of Yubecca Bragg.

Final plunge

Once the water is disinfected, it gets mixed with the leftover water from the Water Plant (the really salty water that is left behind in the desalination process) and released into the ocean. It is now safe and will not harm any of the organisms living in the ocean.

The final plunge
Time to take the final plunge. Photo courtesy of Yubecca Bragg.

Finished, right? …

Are you asking the same question I am?

What happens to the solids?

The waste water operators also monitor the solids, making sure they settle to the bottom of the tanks. Once settled, they will pass into the Aerobic Digester. Here, the air is routinely turned off which allows the clear water (supernatant) to separate from the solids and be recycled back into the trains; this thickens the solids in the Digesters.

Now it’s off to the Sludge Press. What do you think that does? It presses the water out of the sludge!

What’s left is a small, dirt-like Biosolid ‘cake.’ And not the kind you’d like to eat. These biosolid cakes are shipped to the U.S., where it is incinerated.

Why do you think these cakes can’t be used to fertilize fields and crops?

Biosolids 'cakes.' Photo courtesy of Yubecca Bragg.


This one surprised me!

It’s because of the tomatoes we eat in McMurdo! What? The tomatoes we eat in McMurdo come from New Zealand. Tomato seeds are incredibly hardy and can survive not only passing through our bodies. These mighty seeds also survive the cleaning process at the Waste Water Treatment Facility.

Biosolid cake with tomato sprout
Look closely at this Biosolid cake with tomato sprout. Photo courtesy of Yubecca Bragg.

If these seeds mixed with our tomatoes in the U.S., they could possibly cross-breed with our tomatoes and be harmful to the crop. So to the landfills they go!

Were you as amazed by this whole process as I was? It’s fascinating how human waste can be turned into clean water and fertilizer!



Joanna Hubbard

Alex, thanks for the trip down memory lane! I have been fascinated by the waste treatment options in Antarctica - when I was on the Peninsula in 2000, my dive team had been surveying the end of McMurdo's outflow pipe the previous season and their descriptions of the rich marine invertebrate community using our waste was fascinating (and a bit icky). I also got to hear the science talk at McMurdo in 07 from a team taking sediment samples in areas where field teams had camped & had outhouses for a season or two 20-30 years ago. It was a bit horrifying to hear that there was still lots of flame-retardant chemicals from our bodily waste in the sea floor sediment. Just imagine how much is in our bodies.

Rob Hale

The flame retardants detected in sediments near the treatment plant outfall actually arise from indoor dust within the base, rather than from our bodies. We also measured them in McMurdo indoor dust, as well as the sludge biosolids. Levels were just as high as what we see in North America! The flame retardants can degas from furniture, insulation and electronics. Lots of those there. Also these materials may fragment and the particles particles enter the dust. The flame retardant levels in the products we use are actually in the percent by weight range. In dust at the part per million or billion range. So a small amount of fragmented product dust is pretty potent. Unfortunately they accumulate in us and other exposed biota, such as critters near the outfall. If interested, read more at Environ. Sci. Technol. 2008, 42, 1452–1457.

Alex Eilers

Sorry for the late response!
Thanks so much for the comments and I'm glad I could provide a trip down memory lane.

Isn't it all amazing!