Skip to main content
Full Menu

Water system science secrets revealed

New York Teacher

Teacher Christine Hunkele (center) helps students measure the quality of a water

Teacher Sydney Cresap helps out by holding up a color-coded chart.
How much water have you used today? If you’re the average New York City resident, the answer is about 75 gallons. For most of us, the question of where the city’s 1.1 billion gallons of fresh water comes from — and where it goes after we use it — is a mystery.

But not for the students of Christine Hunkele’s AP Environmental Science class at George Westinghouse Career and Technical Education HS in downtown Brooklyn, who got up close and personal with New York City’s water supply on a visit to the Newtown Creek Wastewater Treatment Plant in Greenpoint on Jan. 17.

“We’re currently studying water, so this trip gives students the opportunity to see where our water comes from and how it gets cleaned,” said Hunkele.

The students had a chance to see an underpinning of the city’s infrastructure that few New Yorkers get: Public tours of the Newtown Creek Wastewater Treatment Plant are offered just three times a year. But New York City public school students on class trips are welcome nearly every day.

Newtown Creek is the largest of the city’s 14 wastewater treatment plants, which process more than a billion gallons of wastewater throughout the five boroughs every day. Before demonstrating how the plant operates, Department of Environmental Protection educator LaToya Anderson led the 9th- and 11th-graders through a comprehensive overview of New York City’s water supply.

Watersheds in Croton, Delaware and the Catskills supply water to New York City through a system of gravity-fed aqueducts and tunnels. When water enters the New York City sewer system, Anderson explained, it flows to the nearest wastewater treatment plant, where large debris — more than four tons of it per month — is screened out and sent to landfills. After the water is run through a centrifuge, compressed air helps to thicken and remove any organic waste. The water is then disinfected and returned to New York’s waterways.

“How long do you think the whole process takes?” Anderson asked, prompting a slew of guesses from the students.

The correct answer? Just six to eight hours.

“If you went to the bathroom before you left school, that water has already entered the wastewater treatment plant and will be back out in the New York waterway by the time you get back to school this afternoon,” Anderson said.

Lastly, Anderson noted, any organic solids — collectively known as “sludge” — are treated in the plant’s eight digester eggs, those massive cylindrical steel structures visible from the Brooklyn-Queens Expressway. The digester eggs work just like human stomachs by using bacteria to process the sludge, she explained. The bacteria converts the sludge to methane gas, which powers the plant, or into a solid “cake” that can be used for fertilizer.


The tour ends with a visit to one of the plant’s eight digester eggs.
Wearing hard hats and vests, students check out the view from the glass-enclosed

After the presentation, students divided into groups to test the quality of three water samples. Using color-coded tablets, they measured the pH; iron, copper and chlorine levels; and the hardness of the water.

“New York City has particularly soft water,” noted Anderson. “It’s possibly why the city has such good bagels and pizza — it helps the yeast to rise because the water is so soft.”

After the water-quality testing, it was time to don hard hats and fluorescent vests and tour the plant. The students peered through giant windows at the plant’s boilers and listened to the humming sound of compressed air entering the centrifuge. They murmured appreciatively as they entered what Anderson called “the heart and brain of the plant,” a control room whose huge circuit board resembled a spaceship.

Downstairs, the plant’s old control room provided a stark contrast to the futuristic panel. Populated by seven clunky generators named after the seven dwarves according to their “personalities,” the antiquated space is primarily used for filming period dramas like “The Americans” and “Blacklist,” Anderson told the students.

For the final stop on the tour, students trooped over to the 14-story-tall digester eggs, whose glass-enclosed walkways offer far-reaching views of the Manhattan, Brooklyn and Queens skylines — and a close-up look at the “sludge mixer.”

“The eggs fascinated me,” said Roselyn, a 9th-grader. “I had never seen anything like them before.”

The Department of Environmental Protection offers free class trips to the Newtown Creek Wastewater Treatment Plant in Greenpoint, Brooklyn, for prekindergarten through 12th-grade students. Students learn about New York City’s water cycle through a presentation, a hands-on activity and a walking tour of the facility. To get more information or to book a field trip, visit the Newtown Creek Visitor Center or email

Related Topics: Field Trips
Feature Stories