Wastewater treatment professor to develop biodiesel process
June 22, 2011
BY Luke Geiver
Kartik Chandran might be the best person in the country to develop a new technology for converting organic waste sludge into biodiesel and methane. At least the Bill and Melinda Gates Foundation thinks so. Chandran has been awarded $1.5 million to develop the system that will be put to the test at a sanitation facility in Accra, Ghana.
Chandran, an associate professor at Columbia University, has already achieved a lot in the wastewater treatment sector. Along with his team at the New York City-based university, he developed a system to test nitrous oxide (N2O) emissions at wastewater treatment facilities that has been approved by the U.S. EPA and is now used across the U.S. By looking at the challenges many of the wastewater treatment facilities in New York City are faced with, Chandran was able to design and optimize a system to measure the emissions. “We are surrounded by very sensitive water bodies like the Long Island Sound, Jamaica Bay and the New York Harbor,” he explained. “Until two years ago when we started the project (on emissions), there was no single protocol that could enable or help us to consistently measure those emissions.”
Chandran has developed a unit of measure than can explain a microbe’s propensity to produce nitrous oxide. Wastewater treatment facilities typically employ a biological nitrogen removal (BNR) system that uses nitrifying bacteria to oxidize ammonia which creates a nitrate that is then treated with bacteria that oxidizes the nitrate, eventually turning the nitrate into nitrogen gas to be released into the atmosphere. Chandran’s research, over the past two years, found that when the bacteria used to convert the ammonia become overworked, large emissions of nitrous oxide occur. When treatment facilities are not equipped to handle the overload on the bacteria, significant amounts of emissions occur.
“If nitrous oxide is coming out of the wastewater plant, it is a sign that the plant is not doing well,” but he points out, don’t be alarmed. “We can’t start penalizing wastewater treatment facilities for [N2O] emissions because the wastewater would take a big hit.”
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The waste and fecal sludge to biodiesel work will be done with partners. Ashley Murray, founder and director of Waste Enterprisers, and Moses Mensah, a chemical engineering professor at Kwame Nkrumah University of Science and Technology, will help Chandran. “Thus far, sanitation approaches have been extremely resource- and energy- intensive and therefore out of reach for some of the world’s poorest but also most at-need populations,” Chandran said. “This project will allow us to move forward and develop practical technologies that will be of great value around the world.”
The process the team will work on utilizes the fecal sludge and other organic materials going into the wastewater facility, potentially reducing the amount of waste needed necessary to process. Chandran hopes the new process will change the way we think about human waste. “In fact, the term ‘wastewater’ is already archaic,” he said. “Wastewater is, after all, just water with a different chemical and biological composition.”
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