Study finds effective methods for keeping mercury out of Lake Michigan

2012-03-20T14:30:00Z 2012-03-21T16:05:48Z Study finds effective methods for keeping mercury out of Lake MichiganBy Lauri Harvey Keagle lauri.keagle@nwi.com, (219) 852-4311 nwitimes.com

HAMMOND | Technologies exist that will allow BP's Whiting Refinery to meet federal standards for mercury discharges in waste water released into Lake Michigan, a study commissioned by the company confirmed.

Scientists from Purdue University Calumet and Argonne National Laboratories who examined the issue for more than four years released their findings in a community briefing at the Hammond campus Tuesday morning.

In 2007, BP funded a $5 million grant to the Purdue University Water Institute and Argonne National Laboratories to research technologies that would help the company meet the 1.3 parts per trillion Clean Water Act standard for mercury.

BP officials had appealed to the state, saying current standards are too stringent to meet with existing technologies. Over two years, the company emitted as much as 23.1 ppt.

In February, with the research still under way, the Indiana Department of Environmental Management approved BP's permit modification request for a streamlined mercury variance allowing it to discharge 23.1 ppt.

Researchers lab-tested tested 40 technologies using eight different methods of removing mercury from the waste water.

They found several technologies that brought the mercury levels below the standard, but some were not cost-effective or used too much energy for a large-scale operation, said George Nnanna of PUC's Water Institute.

Scientists ultimately tested two products at BP's Whiting Refinery, an ultrafiltration system created by GE called ZeeWeed 500 and a reactive filtration system by Blue Water Technology called Blue PRO.

The GE product uses fiber membranes called cassettes to capture the mercury. M. Cristina Negri of Argonne National Laboratory said the process provided "very steady performance" and kept the mercury levels at 0.5 ppt, well below the U.S. EPA threshold.

"Ultrafiltration is a technology that has been adopted even at large scale operations throughout the country," Negri said. " ... It has a decent chance of being successful."

The cost of the GE unit would be anywhere from $39 million to $147 million, Negri said, but cautioned that the figure is "a big ballpark."

The Blue PRO unit used feric sand to filter mercury through the combined use of three technologies: precipitation, filtration and adsorption.

Negri said the unit ran from mid-May to mid-August in 2011 and consistently kept mercury levels below the 1.3 ppt threshold, but had a spike above the level in July. When scientists added a chemical to the sand – which is offered by the Blue PRO as an option – the mercury levels fell back below 1.3 ppt.

Negri said further study is needed to see if low doses of the chemical would be successful in keeping the mercury below the level and keeping operating costs down.

The cost for the Blue PRO unit would be between $20 million and $36 million, she said, again stressing it is a broad estimate.

Issues that need to be addressed going forward, Negri and Nnanna said, include how to safely and cost-effectively dispose of the mercury-laden waste.

Lee Botts, a long-time environmentalist from Gary, was instrumental in pushing for further evaluation of the mercury discharge issues and urged the scientists involved in the study to keep the health of the Great Lakes in mind in their future presentations.

"That's what the public needs to know in order to understand the consequences," Botts said.

The final report has yet to be released, but Mitch Beekman, health, safety, security and environment manager at BP's Whiting Refinery, said the company is "anxiously awaiting the full report and recommendations from that."

"BP will be reviewing the report and recommendations in the next few months," Beekman said.

The IDEM permit modification requires continuing investigation into emerging technologies, but does not mandate implementing any of them.

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