River cleaner in Cherry Creek
Standing next to the trash-removal prototype in Cherry Creek are Muaath Albadin, Professor L. Rafael Sanchez and Rida Ezzanagui.

Engineering cleaner rivers

Students and professor collaborate on water-powered trash-removal device

August 1, 2018

Water gurgled as a metallic wheel churned along the surface of Cherry Creek. A woman passerby, taking a lunch-hour stroll along the creek path, stopped for a closer look.

“What are you guys up to?” she asked the three men wading in the stream. L. Rafael Sanchez, PhD, PE, associate professor of mechanical engineering at CU Denver, and two of his students stood next to the large-yet-portable device, looking for ways to optimize action in the weak current.

River trash auger
The device designed by the engineering students works by funneling trash into a cylindrical, rotational auger that scoops and lifts trash out of rivers and streams.

Rida Ezzanagui, one of the students, said, “It clears the river — takes the trash out. It’s all generated by water power.”

“Oh, cool,” she said. “You guys have a good day!”

Learning by doing

Overhead, Speer Boulevard offered welcome shade as Sanchez, Ezzanagui and Muaath Albadin tested improvements to the trash-removal prototype developed last year in Sanchez’s senior mechanical engineering class. At CU Denver, students benefit from an education filled with real-life experiences and learning by doing — all while connected to the vibrant Mile High City.

“It’s been a great experience taking over where other students left off,” Ezzanagui said, noting that this year’s capstone class will continue to refine the environment-friendly device. “We’re checking to see what’s wrong with it, and making some additions and corrections to it.”

Low flows in the creek, caused by the dry summer, rendered a slow churn by the waterwheel, reducing the volume of trash the device could pull from the stream. It simply presents another problem-solving opportunity for the students.

Solutions: ‘We find a way’

“Engineers have to find solutions for problems,” Albadin said with a smile. “Sometimes we struggle, but at the end we find a way.”

Checking trash removal device in Cherry Creek
Mechanical engineering students and Professor Sanchez check on the functions of the device in Cherry Creek.

The device floats on pontoons and works by funneling trash into a cylindrical, rotational auger that scoops and — using power generated by the waterwheel — lifts cans, bottles and other materials out of the waterway. The students are considering adding another power element — possibly a pedal-powered conveyor belt — to enable the device to skim across lake surfaces as it removes trash.

Applying knowledge across globe

Sanchez said the students may enter the modified device in a couple contests — the Greenway Foundation’s Clean River Design Challenge and the College of Engineering and Applied Science’s annual senior design competition — but he’s more concerned with giving the students a well-rounded learning experience. “Winning a student competition would be nice, but it shouldn’t be the main focus,” he said. “What we achieve is more on the learning side and also on the functionality. We make sure the students know how to use gears, bearings, deal with the mechanics of the waterwheel, and understand the physics of the auger scoop and so forth.

“Also,” he said, “it makes students think innovatively about future problems they’re going to face in their professional life.”

It’s the kind of applied learning experience students enjoy every day at Colorado’s only public urban research university.

While Ezzanagui and Albadin are considering whether to pursue careers in environmental engineering, they both would like to apply their mechanical skills to problems in their native countries — Morocco and Saudi Arabia, respectively. “We’re trying to come up with ideas that will help our countries,” Ezzanagui said.