Tech experiment sends algae after heavy metals

A Montana Tech professor and graduate student hope to prove algae can clean the Berkeley Pit water.

Biology professor Grant Mitman and student Nicholas Tucci placed giant, plastic bag "test tubes" in the pit this week to test their theory, which they hope will provide a better and cheaper way to clean the heavy metal-contaminated waters. They should know the results by October, when the bags are removed and the last samples taken.

By Barbara LaBoe of The Montana Standard

http://www.mtstandard.com/articles/2004/06/16/newsbutte_top/hjjfjdidjciaej.txt

The hope is that the algae, as part of their normal process of absorption and adsorption, will clean the water and cause the metals to sink to the bottom. The theory has worked in petri dishes and three-feet long containers. To prove it works in the real world, though, the two needed to conduct the test on a larger scale — and in the pit.

So on Monday, crews from the Montana Bureau of Mines and Geology placed three sets of three 10-foot Limnocorrals — large, specially made plastic bags — into the pit water. The bags each fill with 622 gallons of water, which is then kept separate from the pit as a whole in order to conduct experiments and take readings. Each bag is anchored by a plastic collar that resembles a thin inner tube.

"They’re like giant test tubes suspended in the water," said Tucci, who also designed how to install and maintain the bags as part of his graduate project work.

The bag collars can be seen from the pit viewing stand, but one has to look closely. Every effort was made to keep them unobtrusive and thus undesirable to birds who otherwise might be tempted to land in the pit and check them out.

Algae helps remediate the water because they produce oxygen, which oxidizes the metals and helps them precipitate (drop as solids) to the bottom of the pit. Also, the process helps raise the ph levels in water, which makes the metals drop as well. The pit water only becomes acidic when bacteria converts pyrite into sulfuric acid, so increasing algae should lower the acid levels in the large test tube bags.

"The pit is actually acidic because of biology and we’re hoping with biology of our own we can help clean it up," Mitman said.

The work, funded with a grant, is performed under the Mine Waste Technology Program, funded by the Environmental Protection Agency and jointly administered by the EPA and the Department of Energy. Mitman has wanted to try the experiment for years, but it wasn’t until now that he had the final approval from all the concerned programs. The columns have been used elsewhere for studies, but this is the first time they’re being implemented in Montana, he said.

Algae are ideal for the project because all they need to grow is water, minerals, sunlight, carbon dioxide and nitrogen. All but nitrogen are already present in the pit and nitrogen fertilizer is easily added. In the study, different levels of nitrogen will be added to the bags to determine which is the most effective. One third of the columns will receive no nitrogen as a control group, and samples from the pit water at large also will be used as a second control.

The pit water is stratified, meaning the various levels do not mix with each other. Because of that, anything that sinks to the bottom, like metal precipitates, stays there forever and is not churned towards the top. That would allow researchers to concentrate the metals in one area where they wouldn’t be exposed to or react with the rest of the pit.

The algae won’t clean the water completely, but they could be used in conjunction with other procedures in place or planned for the pit. If it works like he hopes, Mitman said it would be far better and less expensive than dumping lime into the pit. Treating the top four feet of pit water with nitrogen would cost about $40,000, he estimates.

But Mitman is quick to point out that no one yet knows if the algae process will work. That’s the whole purpose of the trial. Favorable findings, however, would be forwarded to Atlantic Richfield Co. and Montana Resources to see if they want to implement it on a large scale.

For Tucci, it’s a chance to finish his graduate studies with a real-life, hands-on project.

"I wanted practical experience as well as lab experience and this is perfect for that," Tucci said. "Tech is the perfect place for environmental science or remediation study, because there’s so much going on here (both pollution and remediation efforts)."

Reporter Barbara LaBoe may be reached via e-mail at [email protected] or by telephone at (406) 496-5519.