Khalili gets her sludge for free from a paper mill in Green Bay, Wisconsin. Paper mills are happy to give me their sludge. Sludge from manufacturing plants must be treated and dried before it can be deposited at landfills. This is an expensive process that companies would like to avoid, especially considering that a day's production of sludge can amount to 250 tons as it does at Encore Paper Co., New York's largest producer of recycled paper. Khalili turns paper mill sludge into activated carbon.
Activated carbon is pressed into a wafer-shaped filter that is fitted into the smokestack.
As emissions pass through the filter on their way out, NOx is removed. Nasrin Khalili reviews her sludge treatment with Hamid Arastoopour, far right, chairman of the department of chemical and environmental engineering at IIT, and two graduate students, Jwalant Vyas, background, and Monika Dukiewicz, far left. She has tested her activated carbon against the commercially produced equivalent and claims that her product works better with a NOx removal capability of 66 percent to 94 percent. The NOx isn't in contact with the activated carbon for very long as it passes through the filter. I am working on developing a method where the activated carbon is introduced into the smokestack as a aerosol.