科学美国人60秒:MacArthur Genius Grant Winner Makes Waste a Resource

“Wastewater itself traditionally has been viewed as something negative, it has been viewed as something that we need to get rid of.”

Environmental engineer Kartik Chandran of Columbia University. On September 29^th he was named one of this year’s MacArthur Fellows, often referred to as recipients of the “genius grants.” Where most people see sewage, Chandran sees a resource.

“To me these are not just waste streams, there are enriched streams. These are enriched in nutrients, nitrogen and phosphorus, these are enriched in carbon, organic carbon. These are also enriched in energy. And so if you now start to think about these as enriched streams, these now contain resources that we could extract and recover and use.

“Using alternate biological processes we can convert the carbon present in these waste streams to methane, and methane can be directly used for energy. We can extract the methane and we can use it for cogeneration of electricity and power. There are many utilities in the nation that actually do this. This changes the game when we are talking about developing or underdeveloped economies where people just don’t have access to sanitation. Because they don’t have access to energy to drive these energy-intensive sanitation processes or wastewater treatment processes. So what we are now doing is, considering, when we start talking about waste streams as energy sources, we are basically driving the treatment of these waste streams from the energy which is produced from within these streams.

“One example of our field work is in Ghana, where we’ve been working with Engineers Without Borders, the student chapter at Columbia University, to design and implement novel toilets that can separate out the urine stream and the fecal sludge stream from human waste. And the end application for this project has been the re-use and recovery of nutrients from the urine stream for agriculture in villages in Ghana. Another example of our field work in Ghana is the conversion of fecal sludge to biodiesel to drive the conversion of fecal sludge to more high-value endpoints.”

For the complete list of this year’s 24 MacArthur Fellows, including about 10 science and medicine people depending on how you define their activities, go to macfound.org, for MacArthur Foundation.

—Steve Mirsky

(The above text is a transcript of this podcast)  

Chandran audio via MacArthur Foundation