High school senior seeks solution to puzzle

Lead High School requires students to complete a long-term senior year project, and three students have taken advantage of the school?s cross-town neighbor, the Sanford Lab, to tackle research related to underground science.

Three years ago, for example, Adam Caldwell designed and built an electronics board for a cosmic-ray detector. Last year, Johan Smith, designed an experiment to test differences in the cosmic-ray flux during the day and at night.

This year, senior Derek Morrison attempted to solve a real-world puzzle at the Sanford Lab?s wastewater treatment plant: Why does the plant work so well?

Water pumped from deep underground in the Sanford Lab contains iron, which, though not toxic, gives the water a reddish hue. The iron must be removed before water is discharged. In 2008, after months of design and testing, Sanford Lab engineers and technicians installed a unique system of sand and geotechnical filters to remove iron. The manufacturers of the sand filters, however, were skeptical the system would work. The filters are designed to remove particles ranging in size from 5 to 10 microns, and the iron particles in the water are in the sub-micron range. Despite that, the plant is remarkably effective. Why?

There are two leading theories. Either bacteria clumps iron particles together or there is an electrostatic attraction between iron particles and sand. Water-treatment consultant Jim Whitlock, who helped design the treatment plant for the Homestake gold mine, said it was important to find the answer. ?We think we can run the plant more efficiently if we understand how it works,? he said. ?So we threw the problem to Derek. We told him, you figure this out.?

Morrison admits the challenge was daunting. ?It seemed more like a college assignment,? he said. First, he designed a scaled-down version of the big Yardney sand filters at the treatment plant. Instead of steel, his filter was enclosed in glass, but the filter media were the same as those in the real treatment plant: layers of gravel, coarse garnet, fine garnet and charcoal. The Sanford Lab Education Department paid for the materials. The treatment plant staff helped gather samples and test the filtered water for turbidity over the course of two months.

Morrison also examined his used charcoal with an electron microscope at South Dakota School of Mines and Technology. Those images suggested bacteria at work.

In addition, Morrison tested the effect of two detergents on the filters: Simple Green all-purpose cleaner (which had no effect) and Dawn dish washing soap (which rendered the filter useless). The lab uses both products and tests those and others to demonstrate whether the materials, when used underground, will impair mine water treatment. ?Derek?s work has real practical value,? lab Environmental Manager John Scheetz said.

Like most researchers, Morrison had to overcome technical challenges. For example, a rubber seal leaked during the periodic ?backwash? processes that keep filters running. ?At one point, I even turned Jim red,? Morrison admitted.

Last week, he presented his research to Sanford Lab staff during a brown-bag lunch. He said his scale model filter would serve two purposes beyond his own research. Water treatment staff will use it to conduct further tests, and the small filter also can be used as a teaching aid for future students.

Regarding his own results, Morrison reported that his research failed to pin down a definitive answer. When pressed for an opinion he said, ?If I had to take sides, I?d say it was some sort of bacterial action.?

Morrison is the grandson of Safety Department Technical Assistant Jeri Mykleby. He plans to attend South Dakota School of Mines, where he will study metallurgical engineering.