FORT LEONARD WOOD, Mo. -- Most people don't give human waste a second thought, except to flush it down the toilet.

But for the people who work at Fort Leonard Wood's Wastewater Treatment Plant, they live -- yes, and breathe it -- day and night, separating water from waste.

The plant takes in an average of two million gallons of wastewater per day. Nine employees, contracted by the Directorate of Public Works, work in shifts to operate the plant, take solid waste to a landfill that is an approved sludge disposal site and make sure clean water goes back into the environment.

"We're here 24 hours a day, seven days a week, and operators make a round every two hours, checking the operations," said Fred Stafford, the plant's lead operator.

Since the wastewater is exposed to the air, the smell can be overpowering. However, Stafford said he doesn't even notice it anymore.

"You get used to it," he said.

The plant was upgraded to a new system and buildings in 2010, which improved water quality and efficiency.

When wastewater reaches the plant, it first goes through the "headworks" building, where a screening process removes rags, grit and debris that are taken to an approved sludge disposal site.

Then, the wastewater gets pumped to the biosolids treatment basin or "racetrack," where it is circulated in a giant maze.

The racetrack holds "bugs," or micro-organisms naturally found in human waste, called sludge. The bugs eat the raw waste to help solidify it for removal, part of the "activated sludge" treatment process that the plant uses.

"We've got micro-organisms in us, helping us digest," Stafford said. "We catch them, we keep them aerated … keep them alive. They eat the sludge (solid waste) and make bigger particles for it to settle out better."

Next, the water goes into the clarifiers: giant, open-air drums where sludge can settle and be collected.

Operators use a truck to cart all of the waste collected-- about 500 dry tons per year --to a site on post.

Being around the waste every day has its risks; it contains pathogens that can make people sick. Wastewater treatment operators receive all of the hepatitis shots to work at the plant.

There is also the possibility of getting spattered. Stafford recalled one incident when he got covered in sludge while trying to fix a machine.

"I was trying to clean the grit system out and it made a volcano, right on a tour" he said.

Luckily, he added, the plant has a built-in shower.

Despite the drawbacks, being around sewage also has benefits, Stafford said: it seems to boost the operators' immune systems.

"If there's a bug on base, we're going to get it first and fight it off, so we usually don't get (as) sick as normal people do," he said.

Don Sechrest, lab technician, takes wastewater samples throughout the process and uses a microscope to check how the water is responding to treatment. He runs about 25 different tests a day, which tell him things like what types of bugs are in the water.

"Different types of bugs will tell you what kinds of treatments you're having," he said. "If you have an overabundance of one, and not the other, that tells you maybe you've got too much sludge in there, or they're getting too old."

In the final treatment stages, wastewater goes through a sand filter, gets chlorinated to remove any last vestiges of bacteria, then de-chlorinated before it gets released into the environment. This is the best part of the job, Stafford said: "taking sewage water and cleaning it up to the point where it can be reintroduced back into the environment."

It is also rewarding to provide such a public safety service, he said.

In fact, wastewater operators are ranked as the second most critical career in America, according to a recent article by Charles Stockdale from "24/7 Wall St." which listed the top "10 Jobs Americans Can't Live Without."