Washington University, two industries, team to clean up mercury emissions


Washington University in St. Louis is partnering with Chrysler LLC and a major Midwest utility company in a project to determine if paint solid residues from automobile manufacturing can reduce emissions of mercury from electric power plants.

A Washington University environmental engineer has shown that titanium dioxide, which is found in paint solid residues from automobile manufacturing plants, can efficiently reduce mercury emissions. Pratim Biswas, Ph.D., chair of WUSTL’s energy, environmental and chemical engineering department, heads a project involving Washington University, Chrysler LLC and Ameren Corporation to test a mercury removal process in a full-scale power plant.

The project is based upon the technical expertise of Pratim Biswas, Ph.D., Stifel & Quinette Jens Professor of Environmental Engineering Science who has demonstrated the effectiveness of titanium dioxide in controlling mercury in lab and recent field studies. He heads the project that will test a mercury removal process in a full-scale power plant.

The electric power industry currently is studying the use of various other chemicals to remove mercury from power plant emissions.

The U.S. government has implemented the world’s first requirements to cut mercury emissions from electric power plants.

For the past year, Chrysler has recycled dry paint solid residues from its two St. Louis assembly plants for use as an alternative fuel in Ameren Corporation’s nearby Meramec electric utility plant. Prior to this project, Chrysler’s St. Louis plants were sending one million pounds of dried paint solids to landfills each year.

Now, the paint solids replace about 570 tons of coal per year in the Ameren plant.

The paint solid residues contain titanium dioxide, which has the potential to remove mercury from coal-powered plant emissions without affecting other processes in the plant. Mercury is chemically bonded with titanium oxide, a process known as chemisorption, and thus is potentially easier to trap in the plant’s emissions scrubber system, research has found.

“Our ‘Paint to Power’ program in St. Louis is a recycling success story. Rather than filling up scarce landfill space, we are using these paint wastes to produce power for St. Louis residents and businesses,” said Deb Morrissett, Vice President of Regulatory Affairs at Chrysler.

“Now we may be able to build on that success to further protect the environment from mercury emissions,”

Biswas, who also chairs the Department of Energy, Environmental and Chemical Engineering at Washington University, and his research team have demonstrated the ability of nanostructured titanium dioxide to remove mercury with greater than 95 percent efficiency. Recently concluded tests in a pilot scale facility have further corroborated the results of the laboratory research.

“Mercury is released into the environment in trace quantities from the burning of coal in electric-generating plants,” Biswas said. “The amount of titanium dioxide in the paint solids from the Chrysler plants would be sufficient to remove the traces of mercury.”

Through its collaboration with Chrysler’s St, Louis assembly plants, Ameren’s 855-megawatt Meramec power plant is the first in the nation to generate electricity by burning paint solids recovered from an automotive manufacturing facility. In the initial phase, the project produces enough electricity to power 70 homes for a year.

The project has been recognized with a pollution prevention award from the St, Louis chapter of the National Association of Environmental Managers and with an Environmental Leadership Award from Chrysler.

The Washington University, Chrysler and Ameren team also received the 2007 Chrysler Environmental Leadership Award.