New technology may make dirty groundwater drinkable

A new technology using nanoparticles - a size 1,000 times thinner than a human hair - is being pioneered by a team of environmental engineers who claim it can cleanse polluted underground aquifers and provide drinking water to an increasingly thirsty world.

Wei-xian Zhang, associate professor of civil and environmental engineering at Lehigh University, said he has a patent pending for his remediation method and has licensed the technology to two environmental companies. He also recently received a grant from the US Environmental Protection Agency to explore the potential for using nanoparticles to treat hazardous waste.

Nanoparticles have been used in chemical processing and electrical engineering for years, but this is the first time they have been applied to groundwater cleanup, said Zhang. "The potential of this technology to help improve the environment is enormous and truly has global implications," he said.

Nanotechnology involves pumping "nanoparticles" - minute, magnetic, iron-based particles so small that 100,000 would fit on the head of a pin, into the groundwater. With a composition that is 99.9 percent iron and less than 0.1 percent palladium, nanoparticles have a large relative surface area and a high rate of reactivity, Zhang said. When applied to water or soil contaminated with carcinogenic solvents used in dry cleaning and industrial processes, nanoparticles remove chlorine and convert the solvents to harmless hydrocarbons and chlorides commonly found in table salt.

The approach is dramatically more effective than traditional cleanup methods that require water to be pumped out, treated, then disposed of, he said.

Nanoparticle technology offers the potential for significant savings. For example, a $20-million clean-up project might cost $5 million, according to Zhang, and nationwide savings could be staggering because the U.S. government projects spending $750 billion in the next 30 years to clean up contaminated groundwater.

Zhang said the method also holds promise for reducing the impact of bioterrorist attempts to contaminate water because nanoparticles can reduce biological and chemical agents quickly. Lehigh researchers say the tiny particles were found effective in detoxifying cyanide.

Source: Water Tech online

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