By Christopher J. Jackson
MONTGOMERY — Researchers at West Virginia University Institute of Technology discovered an inexpensive and recyclable process to extract toxic mercury and selenium from coal wastewater.
Eight years of research paid off for the faculty and undergraduates involved when two patents were filed with the U.S. Patent Office.
“We’ve been very successful and are 100 percent confident,” said Dr. Richard Schoening, professor and chair of the department of chemistry and physics, about the process they’ve developed.
The process uses a population of bacteria that naturally occurs in nature. The microorganisms ingest toxic forms of water soluble mercury and selenium, digests and converts it to an insoluble, non-toxic metal that can be extracted from water, Schoening said.
“The bacteria has no use for mercury or selenium,” said Dr. Jay Wiedemann, associate professor of chemistry and biochemist at WVU Tech, who heads the research. “They’re just converting it to a non-toxic form that they can live in.”
Wiedemann said the process is unique because the microorganisms specifically target mercury and selenium. Mercury and selenium often bond to other non-toxic minerals, forming a matrix of elements.
This matrix makes it difficult to isolate and remove the toxic elements, he said.
Schoening said there are other ways of removing harmful mercury and selenium from a compound molecule, but theirs is more efficient.
“There are other chemical means to do it, but they’re expensive,” he said. “This process is cyclical; we can regenerate the organisms and do their thing again.”
Wiedemann isolated bacteria in a settling pond. At WVU Tech’s lab he added mercury or selenium to the population to raise its resistance.
“When I added mercury (or selenium) slowly I killed off organisms that weren’t resistant,” he said. “So I’m isolating the highly resistant mercury bacteria, then I cultivate it and grow it for bioremediation.”
Bioremediation is using naturally occurring microorganisms to consume or break down pollutants.
Wiedemann, with undergraduate researchers, fills a bench-top bioreactor — a column with a filter system in it — with the bacteria and runs contaminated water through it. When the water comes out it’s rid of toxic forms of mercury and selenium.
Their water sample contained 50 parts per million of the toxic mercury. This means there are 50 million mercury atoms in the water. A new Environmental Protection Agency regulation has reduced the previous amount allowed of .0005 parts per million to .5 parts per billion.
Lab results shown that 94.8 to 100 percent of toxic mercury was removed from their water sample, Schoening said. This means water containing 50 ppm of mercury was reduced to 0 to 2.1 ppm.
The percentage is based on a reading by an atomic absorption spectrophotometer (AA). The instrument cannot detect lower than the range of 0 to 2.1 ppm.
“We cannot detect any lower than that,” Schoening said about the AA. “So we list it as the minimum detectable. Based on the result, this would mean the mercury (in most toxic form) has been reduced to 94.8 to 100 percent of its original value within those detection limits.
“The mercury has been converted to mercury metal in the reactor and can be removed by the system.”
The same process and findings are similar for selenium, Schoening said.
Mercury is a poisonous byproduct of coal’s combustion. Coal contains about 1 ppm of mercury. After its combustion the toxins left are often kept in settling or slurry ponds.
Selenium is found in the soil. When mountaintop mining occurs, the soil is disrupted. When it rains, the selenium becomes soluble and washes into streams, Schoening said.
WVU Tech’s findings couldn’t have come at a better time for the coal industry as the debate between the environmental effects of coal mining and coal-fired power plants rages on.
“The problem is when it rains there may be overflow and the mercury (and selenium) can be washed into streams,” he said. “And the other problem is when these ponds leak.”
In 1972, Pittston Coal Co.’s coal slurry dam broke in Logan County, unleashing 132 million gallons of coal wastewater along Buffalo Creek hollow with a population of 5,000. One hundred twenty-five people were killed, 1,100 were injured and 4,000 left without a home.
Removing these won’t make them completely safe, but it’s a step in the right direction, Schoening said.
“They become somewhat safer,” he said, “but there may be other metal toxins in there as well, such as chromium, cadmium and lead.”
Their findings haven’t come by the hands of graduate and post-graduate students as this type of research normally entails, but has come by the hands of undergraduates, Provost Scott Hurst said.
“This demonstrates what we try to foster here,” he said. “Scientists have developed a way of educating students through research at the undergraduate level, which is somewhat unprecedented in the state and in general because most research is done at research intensive institutions, mostly by graduate and post-graduate students.”
Schoening said the research has excited students to pursue higher education.
Mike Booth, an undergraduate heavily involved in the research, and who is attending Virginia Tech for graduate studies, said the experience will have him better prepared.
“There’s no substitute for going in a lab and being hands-on,” the Barbour County native said.
Another student who has helped tremendously with the research, Rebecca Martin, said it has better prepared her for graduate school.
“I feel confident,” the Kanawha County native said. “When I start my own research, I feel I’ll be able to compete with some pretty bright people.”
This research has been conducted in a makeshift lab, which used to be a chemical storage room. WVU Tech is seeking funds for a state-of-the-art biochemistry lab.
It is also in need of funds to build a prototype bioreactor to demonstrate the mercury and selenium process at sites.
For any information regarding funding or for a tour of the institution, contact Provost Hurst at 304-442-1025
— E-mail:
cjackson@register-herald.com
