University of South Carolina

Engineer studying waste reduction technique

A century-old method used to convert carbohydrates into coal is getting a second look as a sustainable technique for dealing with municipal solid waste.

Nicole Berge, an assistant professor in the Department of Civil and Environmental Engineering, has received a five-year, $411,000 CAREER Award from the National Science Foundation to study a process called hydrothermal carbonization.

“Waste is placed in a reactor with water, then heated to 200-300o C. At that temperature, the water behaves like an organic solvent, promoting reactions that result in a substance called hydrochar,” Berge said. “This method was developed in the early 1900s to make a form of coal, but the chemistry of what takes place in the reactor has never been completely understood.”

Hydrochar is a charcoal-like substance that contains most of the carbon from converted waste. Capturing the carbon into a solid form prevents its release as a greenhouse gas (CO2 or CH4), which, along with reducing the overall mass of municipal waste and high energy content of the hydrochar, is an allure of hydrothermal carbonization.

Berge will conduct laboratory-scale testing of the process, focusing especially on gaining a mechanistic understanding associated with the hydrothermal carbonization of materials and determining the energy requirements necessary to break down various types of municipal waste.

“This has the potential to be a very beneficial technique for solid waste engineering, and it could translate to other types of waste that are responsible for greenhouse emissions such as pig manure,” Berge said. “Before application of this technique, we have to understand exactly what’s in the char.

“It’s possible that the char could be used as a feedstock in a coal-fired generating plant, a soil amendment, or as an absorbent for environmental remediation.”

The Max Planck Institute in Germany is studying hydrothermal carbonization as a method to develop novel nanomaterials that could be used for various applications.



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Posted: 04/07/11 @ 1:00 PM | Updated: 04/08/11 @ 9:46 AM | Permalink