Take a close look at that cheap piece of scrap iron before you toss it in the trash.
Wei-xian Zhang has a good use for it. Someday soon, much of the world might also.
Zhang, a professor of civil and environmental engineering, recently concluded a five-year research project in which he and his colleagues at Tongji University in Shanghai used two million pounds of iron to detoxify pollutants in industrial wastewater.
The project, carried out in Shanghai, was the largest in history to use iron in an environmental application. The iron, called zero valent iron (ZVI) because it is not oxidized, was obtained in the form of shavings or turnings from local metal-processing shops for less than 15 cents a pound.
An article written by Zhang and Luming Ma, professor of environmental engineering at Tongji University in Shanghai, was published recently as the cover article by Environmental Science and Technology. The article was titled ""Enhanced Biological Treatment of Industrial Wastewater with Bimetallic Zero-Valent Iron." ES&T, a bimonthly published by the American Chemical Society, is the leading journal of its kind.
The ZVI project began with small, "benchtop" experiments in the laboratory that used a total of 90 pounds of iron to treat toxins in solution. It graduated in 2005-06 to a pilot test using 2,000 pounds of iron to pretreat wastewater at a treatment plant in the Taopu Industrial District in Shanghai. Wastewater at the Taopu plant, which is generated by small chemical, materials and pharmaceutical companies, had previously been treated with microorganisms alone. ZVI augmented and improved this remediation method.
Following the pilot test, the Shanghai city government approved a grant to construct a full-scale treatment reactor in the Taopu district capable of processing almost 16 million gallons a day of wastewater. This ZVI reactor was connected to the biological treatment plant two years ago
|Contact: Kurt Pfitzer|