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Where does our poop and pee go in Dallas? 

It’s true what they say. Poop really does roll downhill.

It’s true what they say. Poop really does roll downhill.

After you make ... let’s call it a deposit ... in Dallas and flush, water carries whatever was in the toilet through a pipe, usually about four inches wide. What goes down the sink follows the same route.

The pipes tilt downward, taking advantage of gravity, growing larger and going deeper into the earth as the muck travels two to four feet per second. By the time the pipes reach the Central Wastewater Treatment Plant — one of several treatment plants in Dallas — they are big enough to drive a truck through and 70 feet underground.

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A reader asked our Curious Texas project, "where does our poop and pee go?" It's a "serious question" added the asker, who goes by Teenage Moriarty.

Curious Texas, a special project from The Dallas Morning News. You ask questions, our...
Curious Texas, a special project from The Dallas Morning News. You ask questions, our journalists find answers

We took the question seriously and toured one of Dallas’ wastewater treatment plants. We tried to invite the reader along. But not only is Teenage Moriarty apparently a nom de plume, the reader gave us a bad email address. But we were intrigued and decided to find out the answer kids from 1 to 92 ask about and then giggle.

The plant is run by Daniel Halter, a mechanical engineer from Wyoming who drives a 1996 beige Cadillac with the license plate CWWTP. Yes, that stands for Central Wastewater Treatment Plant, and it's his personal vehicle.

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"If it was flushed, it ends up here," Halter said. "Sometimes we see a little Barbie head. Probably a little brother being mean to his sister."

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Does the plant smell?

The smell of sewage hits about a half-mile from the plant.

Fumes grow stronger the closer you get to the administrative offices. The odor is enough to make you gag, depending on which way the wind blows. But most of the time during a recent visit, the smell was more chemical than fecal.

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“I apologize in advance for  the smell,” Halter said at the start of the tour. “But, to me, it smells like money.”

It’s kept him employed for 18 years.

What happens once the sewage makes it to the plant?

After a filter blocks out large items, such as a Volkswagen hood, machines that act as a large rake pull out solid materials. “Flushable” wipes, plastic bags, paper. They end up in an enormous dumpster headed for a landfill.

It’s here that employees sometimes find turtles.

Not all survive, but the ones that do are moved to a turtle sanctuary inside the administrative offices. Eight live among the water, rocks and plants, and another three call Halter’s office home.

Most are eventually released to the wild.

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Spike, a grumpy snapping turtle, serves as plant mascot. He’s best left alone. Crazy 8 is a turtle whose shell didn’t form properly after it got caught in a condom. The middle of the shell turns inward, where it was caught while the rest of the shell grew.

At other stops, dirt and other grit is removed by gravity. Another machine pushes muck entangled with hair into another dumpster headed to a landfill. Never stand downwind while this happens.

Along the way, water will have been cleaned nine ways, including by filters, microorganisms, chemicals and gravity. Eventually all that will be left is water that looks as pristine as what you’d find in a swimming pool.

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Where is the treatment plant?

Halter’s plant sits on 300 acres of what used to be farmland about 3 miles south of downtown. About 60 maintenance staff, 40 operators and three engineers report to him.

The city bought the land in 1913, planning for growth.

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What do the microorganisms do?

They are the same “bugs,” as Halter calls them, found in your gut that help digest food. But while our bodies might keep food for 12 hours, the treatment plant microorganisms feed on the sludge for up to 17 days. Our bodies leave a lot of food undigested.

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What should we stop flushing?

So-called flushable wipes have caused problems for other cities. But not in Dallas, mostly because of the large size of the pipes. Clogged pipes happen and flushable wipes are found in the blockage. But Halter said it’s impossible to tell whether the wipes are the cause.

Grease balls the size of chairs used to show up at the plant. But a push against pouring grease down the drain has resulted in more manageable, golf ball-sized globs. They look like tan vomit.

Condoms and plastic tampon applicators can make it through several stops before they are weeded out.

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Treated water flows into a wetland that feeds into the Trinity River at the Central...
Treated water flows into a wetland that feeds into the Trinity River at the Central Wastewater Treatment Plant in Dallas. (Nathan Hunsinger / Staff Photographer)

What happens to the water?

The water, now clear, is treated with chlorine. Two golf courses buy the water for irrigation. As a bonus, it also works as a great fertilizer

The water isn't drinkable. But the water is used around the plant. Lavender pipes carry this water, which is used to do things like propel the trash removed from the sewage into another large container that is headed for a landfill.

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The remaining water is treated with sodium dioxide to neutralize the chlorine before it's released into a wetland that feeds into the Trinity River. The treated water has fewer pathogens than regular river water.

Could the water be treated enough to drink?

It could. But people would “freak,” Halter said.

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Plus, making the water that clean would cost a lot.

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