"Sustainability by Design," Input/Output, ME Departments, January 2008

input/output

Sustainability by Design

by Jeffrey Winters, Associate Editor

When it achieved independence in the 1950s, Ghana was seen by experts as a potential emerging power. It had abundant natural resources and a population that was well educated by West African standards.

Fifty years later, however, much of that original promise has not been realized. And even where development has occurred, the effects haven't been as long lasting as expected. The countryside is littered with abandoned projects, and the nation's crown jewel, the massive Akosombo hydroelectric dam on the Volta River, can no longer be relied on to supply electricity.

That's the reality Toby Cumberbatch wants to show his engineering students. Cumberbatch, a professor at the Cooper Union for the Advancement of Science and Art, a private, free-tuition college in New York City, lived in northwestern Ghana, where his father was a doctor, just after independence. "Ever since I started at Cooper," Cumberbatch said, "I've wanted to take students back there." In the past few years, he has led groups of students to the northern sections of Ghana.

On the most recent trip, Cumberbatch and his students, with the help of funding from the National Science Foundation, began to tackle three longstanding problems for the people living in the rural north of Ghana. One group looked at electric lights independent of the grid; another, housing that doesn't rely on concrete trucked in from the coast; and the third, drinking water that doesn't contain debilitating levels of fluoride. What's more, the solutions have to work within the constraints of West African culture, meaning they need to be inexpensive and easy to maintain. "There's phenomenal engineering to be done there," Cumberbatch said. "It has to be cheap. It has to use different materials than we're used to. And has to be able to be made over there. Too much stuff is being imported already."

"In that situation, you can't always use the most elegant solution," said Eleanor Baum, dean of engineering at Cooper Union, adding that the challenging engineering environment was meant to stretch the students' way of thinking about problems.

Cooper Union engineering students and Ghanaian water managers examine a sealed borehole.

Lighting is a big problem for people who live away from the national electrical grid, even when it is working. Kerosene lanterns are the most common source of light, but fuel can be hard to come by in remote locations. A group of Cumberbatch's students studied the problem and designed an alternative light powered by solar panels and rechargeable batteries and built from such materials as empty soda bottles and bamboo.

An architecture student is studying how to make huts from mud—the material of choice for centuries—that are as durable and weather-resistant as the concrete and tin roof houses that have largely replaced them.

But on the invitation of a director of a regional sanitation agency, a team of students is working on the project that might have the most immediate impact: a water filter now being designed in Cumberbatch's lab at Cooper Union. The goal of the filter is to clear well water of fluoride, which at high levels can actually eat away at the teeth of children, leaving them permanently disabled. Naturally high fluoride levels are common around the globe and there are many systems available for treating the water, but they all suffer from high costs and a problematic level of complexity for villagers. Cumberbatch and a group of students spent part of their time in Ghana talking with water managers and consumers in the Upper East region of Ghana to get a handle on the problem. What was needed was a filtering system that could run more or less autonomously, using materials readily at hand. One such material is the aluminum-rich mineral laterite, which is found in local red clay soil.

"In the places around the world where fluoride is a problem, laterite is common to all of them," Cumberbatch said. That means an engineering solution that uses laterite in combination with other common materials could have application worldwide.

After conferring with regional water managers (who built a remote lab for testing the solutions) Cumberbatch's students returned to New York to try various designs. With luck, the Cooper Union fluoride filter will be tested during next year's Ghana trip.

"The water filter has to be designed so it can be built on site," Cumberbatch said. "It has to be well en- gineered, and you need to talk to people who are going to use it. Unfortunately, most places don't teach that people are an integral part of the design process.

"For the students who have gone, it's changed the way they see the world," Cumberbatch added. "The way we in the developed world look at engineering isn't the best way or the purest way of looking at engineering from the global point of view."