Antarctica is perhaps the most pristine place on Earth, but it takes a great deal of effort to keep it that way. The population of Antarctica—mainly researchers and support staff—swells to about 5000 in the summer months, and the number of tourists that visit during this peak travel season sometimes exceeds 40,000.

The problem? Where there are humans, there is human waste—and loads of it. Waste removal is a problem affecting other hard-to-reach places, like Mt. Everest in Nepal and China, and Denali in Alaska. China recently announced that climbers on the Tibet side of the world's highest peak would have to start carrying away their own poop, while scientists in Alaska warned that global warming could cause an estimated 66 tons of frozen feces on the mountainside to melt.

There are international rules in place to make sure Antarctica doesn't acquire a similar problem. The continent is protected under the Protocol on Environmental Protection to the Antarctic Treaty from 1998, which stipulates that "the amount of waste produced or disposed of in Antarctica should be minimized to protect the environment and other Antarctic values" [PDF].

However, much of the law is left up to interpretation, with waste treatment procedures varying from one research station to the next. Some of the waste gets treated, then shipped back to various countries, including the United States, Australia, and New Zealand. In other cases, waste is treated and dumped into the ocean.

The day-to-day logistics of doing your business depend on the location, too. Many of the larger research centers have flush toilets, including the American-run McMurdo and Amundsen-Scott South Pole stations, but these modern comforts are harder to come by away from base.

In lieu of flushable loos, some stations require the two kinds of waste (solids and liquids) to be processed individually. This can mean separate toilets for separate bodily functions. Out in the field, researchers may need to use poo buckets and pee bottles (women included). And in certain locations, both China and the U.S. use "rocket toilets" (officially known as incinolets) that burn the waste, reducing it to ash.

Indeed, while everybody poops, not all of it gets treated in the same way. Here's how two different research stations in Antarctica are handling their waste.

The United States’s McMurdo station

Eli Duke, Flickr // CC BY-SA 2.0

McMurdo Station, the largest research station on the continent, is situated south of New Zealand on Antarctica’s Ross Island. It accommodates an average of 850 visitors during the busy summer season, which translates to a whole lot of human waste.

For decades, the station macerated its poop (reduced it to smaller particles) and then released the byproduct directly into the ocean. In 1989, a U.S. official told The New York Times, "Waste disposal in Antarctica used to be a disgrace. But during the past half-dozen years we've been correcting the sins of earlier generations."

It wasn’t until 2003, though, that McMurdo Station got its very own waste treatment plant connected to its network of flush toilets. The waste gets mashed up by two JWC Environmental Muffin Monster grinders, and those particles then undergo a UV disinfection process. The liquid end-product gets pumped into the ocean.

Any solid waste that’s leftover from the treatment process gets packed up and shipped back to America on cargo ships that bring supplies to McMurdo Station on an annual basis. The ships also transport recyclables, food waste, and scientific samples back to the U.S.

“The U.S. takes its commitment to the environment seriously, and outside of gray/black wastewater [what flows into the wastewater treatment plant for processing], everything is removed from the continent and taken to the U.S. for final disposal,” Peter West, polar outreach program manager of the National Science Foundation, which runs McMurdo Station, tells Mental Floss. “Even some of the gray/black wastewater from field camps is taken to the U.S. for disposal.”

Australia’s Davis station

Torsten Blackwood-Pool, Getty Images

Australia’s researchers used to have a pretty big poo problem. After a waste processing plant at the country’s Davis research station broke down in 2005, they had to resort to other means of eliminating the waste left behind by the 120-some scientists and staff who stay there each summer. Instead of the waste being treated, “sewage was burned or else discharged with little or no treatment straight into the sea,” the Australian Antarctic Division (AAD) writes on its website.

That disposal method had an unfortunate effect. A 2010 study revealed that the fecal matter wasn’t dispersing well once it was piped into the sea. Instead, it was clumping up in certain areas, exposing nearby seal and penguin populations to high levels of bacteria. These contaminants ultimately wound up in the marine food chain, with “sewage markers"—certain stable isotopes linked to sewage intake—being discovered in a snail and a fish.

To address this problem, a new wastewater treatment plant was constructed at Davis station, which is located along the Ingrid Christensen Coast on Princess Elizabeth Land. But before they could start using it, they had to wait for the microbial green light, so to speak. “Wastewater treatment plants rely on microbes to eat much of the waste in the wastewater, and it takes a while for these to multiply sufficiently to do this job when starting a new plant,” Michael Packer, Australian Antarctic Division engineer, tells Mental Floss. “Anywhere else in the world, this process can be kickstarted by introducing doses of these microbes. In Antarctica it is a bit more tricky as we don’t want to introduce foreign species to the environment down there.”

Once the naturally occurring microbes started reporting for duty, the plant became operational in 2016. It soon began transforming waste “into some of the cleanest water in the world,” according to the AAD. When a more advanced stage of treatment goes into effect later this year, the quality of the treated wastewater will improve once again. “It will be even cleaner than the water that comes out of the tap in the average Australian house,” Packer says.

From there, the water is discharged into the ocean. Any leftover solid waste is then concentrated in a decanter and shipped back to Australia.

And yes, in case you were wondering, all three of Australia’s research stations have flush toilets. Any researcher who has to answer the call of nature while away from Davis station must carry their waste with them so that it can be treated back at base.

Suffice it to say, if you're planning to visit one of the most remote regions of the world, don't forget your bottle.