About 12 years ago, Kevin Cini looked around at his colleagues in the City of Groton Utilities Wastewater Treatment Plant and realized that he was the youngest one there, at age 40.

"I said, 'Someday, all of us are going to retire and there's going to be no one here to take over the plant'," said Cini, the chief plant operator. So he contacted the mayor's office and then the dean of students at Ella T. Grasso Technical High School, and created an internship program to teach one student per year how the plant worked.

Today, two of those former Groton students - Joshua Rezendes, who came from Grasso's biotechnology shop and Eric Melanson, who came from the plumbing shop, are full-time plant operators. A third student, Kelsey Reeves, 20, of Ledyard, is an environmental engineering student at the University of Connecticut, who recently learned about renewable technologies overseas.

Rezendes graduated in 2008. The summer before his senior year, he said the dean of students asked if he'd be interested in an internship at the wastewater treatment plant.

"At first I thought, 'Why would I do that? It's sewage, right?' " Then he found out the internship paid $10 an hour, a fortune to a 17-year-old, he said.

It ended up different than he expected.

"I talked to the guys down here and I learned a lot," he said. "There's a lot of science involved, and science in general is what I was interested in."

Reeves, who came from Grasso's plumbing shop, started her internship four years ago and just returned from the two-week "Green Program" in Iceland that teaches about renewable energy. She toured facilities like geothermal plants, or ones which use heat from inside the earth to create power, and hydropower plants, or ones which use the force of rushing water to turn a turbine and a generator.

She said she likes working in the field and wants to design a wastewater treatment plant for a country that doesn't have one.

"What I really like is not only are you helping the environment, but you're helping humans," said Reeves, who this summer is helping pump sewage from boats. "If we didn't have wastewater plants, everyone would be very, very sick."

Cini said Reeves' focus and drive sets her apart.

"She starts out every day with an outline. This is what I'm going to get accomplished today," he said.

In January 2012, Reeves built a biofilter to remove odors from around the Groton Utilities wastewater treatment plant. Her project was chosen by the New England Water Environment Treatment Association and presented at their conference in Boston.

In spring of 2012, Reeves also gave a presentation to the same organization about how the treatment plant removes nitrogen from wastewater to minimize pollution.

She won the presidential scholarship at Grasso, which paid her college tuition for four years. Yet she said she had trouble getting into a college. She didn't take a foreign language because her schedule was full with other academic and shop classes, she said.

Now she's trying to take everything she's learned and weave it together.

In addition to her internship at the Groton wastewater treatment plant, she also spent one summer as an intern for Tighe & Bond, an engineering and environmental consulting firm with offices in Middletown.

"My goal is to be able to set up wastewater treatment in third world countries, where they don't have the technologies," she said. "I want to take what I've learned here, what I'm learning in college, and what I learned at the Green Program and put them all together."

If possible, she'd like to use renewable energy for the plant she designs. But she doesn't know how it would work yet, because technology changes fast. She's a junior this fall.

"By the time I get there, the world will have changed so much," she said.

D.STRASZHEIM@THEDAY.COM