In water system engineering, local is the new global
Engineering students must learn how ‘decentralized’ systems offer flexible, cost-effective solutions that empower communities.
Michigan Engineering News
The world of tomorrow will demand a different kind of water engineer—one who can understand and innovate more sustainable and specialized systems in the U.S. and in developing countries.
But today’s textbooks don’t adequately prepare them for this charge.
Nancy Love, the Borchardt and Glysson Collegiate Professor of Civil and Environmental Engineering at the University of Michigan, is leading an international team that’s working to change that. Love is partnering with Geremew Sahilu, assistant professor of civil and environmental engineering at Addis Ababa University.
Together they’re developing curriculum to train students in both countries how to design “decentralized” water systems. These are smaller-scale approaches to distributing drinking water and treating wastewater that don’t rely on an expensive central treatment plant and a complicated network of pipes.
The benefits of decentralized water systems
“In the United States, drinking water systems and—at the city level—wastewater systems are what we call centralized,” Love explains. “We have large treatment plants that process the water. In the wastewater case, the system puts it back in the environment, and in the drinking water case, it distributes it to the consumer.
“The reality for many cities in Africa and South America and other parts of the world—and increasingly in some parts of the United States—is that centralization is a very inflexible approach. It’s also not a reality for some of these cities, certainly not for the next several decades. And it may not be the most resilient way to build water systems.”
Some level of decentralization makes sense in the U.S. and abroad, Love says. Domestically, we need more sustainable solutions, and more flexible approaches as the climate changes. Today, a hurricane could knock out water infrastructure for a large area, and it could take weeks to get it back online. Decentralized, neighborhood-scale approaches could be up and running again much faster.
In developing countries, decentralized approaches make sense as economical ways for cities to grow. Many parts of the world rely on small-scale systems today, but they need better ones, Love says.
Addis Ababa, Ethiopia, for example, has a centralized wastewater plant, but it serves less than 10% of its population. The rest of it is decentralized.
“It’s fecal sludge management, picking it up by a truck and delivering it to one location that may or may not treat it. We need better solutions to handle the sewage and septage at a local level, at the neighborhood scale. It could be in the basement of a building, for example,” Love said.
Education for tomorrow’s water solutions
Previous generations of civil and environmental engineers, water system engineers included, were taught to think of gold standard infrastructure as large scale—sprawling webs of highways, power lines and pipes. In recent years, the view has both broadened and narrowed. It has broadened to encompass impacts on the planet and society as a whole, including those related to environmental justice. It has narrowed in its identification of solutions: local is the new global. Love and her colleagues are building a bridge to that future.
“When I go visit the faculty collaborators I have in Ethiopia, I see the textbooks on their bookshelves and they are the same textbooks that I have on mine. They’re focused on large-scale, centralized systems. We don’t teach about decentralized systems in the water sector; I’m not sure we teach it in other public sector services either. So what this collection of classes we want to build that repertoire and knowledge base, both in our students as well as in students at Addis Ababa and other places. The ultimate goal is to get that curriculum online and make it open-access.”
As part of the curriculum, Love is piloting a course at U-M this semester called Project-Based Urban Water Systems. Many of the hands-on projects student teams are working on have applications at home and abroad. One team is advancing chlorine-level monitoring that residents could do with their cell phones. Chlorine levels give a sense of whether water is being adequately treated for microbes. Another is studying soil moisture levels, which could inform stormwater management decisions. A group is building a hydraulic model of a section of Addis Ababa, so city officials have a better sense of the pipe sizes and water pressure throughout the distribution system. Hydraulic models could inform site locations for future decentralized nodes. Finally, a team is examining Addis’s master plan and how implementing it will help or hinder the development of decentralized solutions. They aim to provide insights into whether certain areas are at risk of flooding, limited water availability or unsafe water.
Empowering communities
The course, and the curriculum, are an exchange. Sahilu has spent time in the class here in the U.S. And many of the students will travel to Ethiopia this summer.
“The world is a village now,” he said. “Scientific knowledge doesn’t have a border, but it should expand through collaboration.”
And it should expand to people who aren’t scientists and engineers.
“Decentralization will involve the consumer more,” Love said. “They will be more connected to their water.
“This work is really designed to empower the Ethiopians to come up with their own solutions, and to partner with them in ways that both build their curriculum and build their graduate research capacity so that these solutions are their solutions.
“That’s what the research projects I work on are about. It’s really capacity building, plain and simple.”