Seeking Sustainability

Engineering for an environment of climate change, population pressure, and limited resources.

All around us, it seems, interest in the environment is on the upsurge. Witness the abundance of media stories on global warming, for example: How are polar bears and, ultimately, people affected by melting permafrost? How do rising ocean temperatures damage coral reefs, and how, then, will coastal regions combat catastrophic flooding wrought by hurricanes or tsunamis?

Meanwhile, oil giant BP sports the slogan “Beyond Petroleum,” and General Electric, the world’s largest corporation, makes news with its 2005 pledge to curb its greenhouse-gas emissions by 1 percent by 2012. And just last year, the national science academies of the G8 nations—Canada, France, Germany, Italy, Japan, the United Kingdom, the U.S., and the Russian Federation—along with China, India, and Brazil, signed a joint statement urging countries to take prompt action to curtail global warming.

Of course, global warming (owing largely to carbon dioxide in the atmosphere) is one of many environmental concerns, albeit a far-reaching one. The energy sources we use, the materials we require to fashion consumer products, the ways we dispose of chemical, biological, or nuclear waste–all come with trade-offs and consequences, and sustainability, defined as living off the interest of our natural resources rather than the capital, is becoming a byword for industry and the engineering profession.

Imagine, for instance, that everyone in China opted to eat one egg a day. That’s about 365 billion eggs consumed each year. What impacts would such consumption have on the planet? It’s a question that Suresh Rao, Purdue’s Lee A. Rieth Distinguished Professor of Environmental Engineering, likes to put to students. Beyond the need for a lot of chickens is the need for a lot of grain—about 60 percent of North America’s grain export.

Students then need to consider all the environmental consequences of growing the crop and raising the chickens required. Then they’re asked to imagine the same decision made in India, a country of another billion people. The approach examines the full costs and broad consequences of a decision and its sustainability.

Larry Nies, Rao’s colleague and a professor of civil engineering at Purdue, teaches an “Engineering for Sustainability” course in which students explore similar interconnected issues (America's Energy Production). “There are more than 4 billion people whose quality of life is poor by American standards,” he says. “In addition to consuming one egg per day, what if we include a pair of tennis shoes, a cell phone, a computer, an automobile, and a single-family home in the equation? The increase in ecological stress caused by the industrial production of these commodities would be unprecedented.”

Environmental engineering has come a long way from its roots in sanitary engineering, a discipline stretching back millennia. (Among the earliest-known artifacts of sanitary engineering is a sewer arch excavated in Nippur, India, dating to 3750 B.C.) In the 20th century, Purdue made a name for itself in the areas of water quality and sanitary engineering, fields whose impact, says Bill Wulf, president of the National Academy of Engineering, has been greater than medicine’s in improving the health of people around the planet.

Today, some 65 faculty members across the College of Engineering’s 350-member faculty engage in activity that can be termed environmental engineering or that is related to the environmental impacts of their primary disciplinary activities, whether in transportation, manufacturing, or energy production and utilization.

More than most engineers, environmental engineers work across the boundaries and at the interface of natural and engineered systems, and they work in interdisciplinary teams with colleagues in the natural and social sciences. That interdisciplinary focus—that recognition of interrelationships of all kinds—is essential.

“To begin addressing problems associated with climate change, allocation of finite resources, regional water scarcity, and coastal hypoxia [depletion of dissolved oxygen in the water], engineers must now incorporate ecological, social, legal, and economic constraints into their designs,” says Rao. Through research, education, and the newly launched Center for the Environment, Purdue is equipping us all to reap the benefits of greener engineering.