By Michael Souza
PBN Staff Writer

Engineers and scientists at Brown University are using a combination of two established – but very different – techniques in an effort to efficiently remove heavy metals from industrial wastewater.

The presence of metals in wastewater is a common problem for many industries, including the manufacturing of printed circuit boards, jewelry and electroplating. If not treated correctly, these metals can cause compliance problems with state and federal officials. Some standard treatment methods can be problematic, consuming inefficient amounts of power or generating sludge classified as a hazardous material, requiring further treatment or special disposal.

“The primary target is remediation of wastewater contaminated with a variety of heavy metals present at low concentrations,” said Joseph Calo, research professor at the School of Engineering. “The combination of complex metal mixtures and low concentrations makes this task particularly difficult.”

That is why Calo is developing a new method that collects trace amounts of heavy metals in water by increasing their concentration, so that a proven removal technique can be utilized. Called cyclic electrowinning precipitation (CEP), the method removes up to 99 percent of copper, cadmium and nickel, according to his research.

Once treated, the contaminated water will meet federally accepted standards. The system’s mechanics and results of wastewater-treatment studies have been published in the Chemical Engineering Journal.

Calo recently submitted paperwork to university officials, who have the right of first refusal, in the hopes that the school applies for a patent. Should the school decline he has the option to patent the system himself, as is the standard practice.

“What we’ve found is something that is very promising. It’s a complete system and it has commercial possibilities,” he said.