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BC Scientists Practice Problem-Based Learning

Berea College chemistry professor, Dr. Paul Smithson, has been able to engage several enthusiastic students in research projects that involved problem-based learning over the past several years. He recently reported the findings of those projects to his colleagues at the monthly Friday Faculty Colloquium.

Dr. Paul Smithson details student research projects

In summer 2003, chemistry major Jami Rogers and Smithson gauged methane production in swine waste using samples from the college farm’s swine waste lagoon. The college has a relatively small hog operation, raising approximately 400 a year, but the methane in the waste lagoon is still evident. “On a warm summer day you can just see it bubbling," Smithson says. "Anaerobic decomposition of organic matter produces biogas, which is 60 percent methane (natural gas) and 40 percent carbon dioxide – a potential energy source to supplement the high-priced energy source that we use at the farm.”

Rogers, with Smithson’s assistance, measured the acidity and methane content of the daily samples. A spike in methane occurred around July 4 and to find out why, the ph factors were measured and high acidity was found. “We added lime to balance out the acid formers and started seeing a recovery in a few weeks.”

According to the professor, at first it appeared that nothing would come of their research. “But Jami wanted to keep it going when I was ready to throw it out. I’ve learned to listen to the students.” The duo concluded that methanogens are sensitive to acid conditions and acid-formers are fast growing and need careful management of inputs.

A two-part problem-solving research project involving the college’s swine production took place over two short terms. Professor Mike Panciera told Smithson that there were concerns about the two swine waste lagoons. They were periodically pumped down to prevent overflow and provide nutrients to the pastures, but during periods of heavy rains overflow occurred. It was feared that this was contaminating the lake 500 feet away that provides drinking water to cattle and other livestock.

Geographical Information System mapping photos revealed two probable overflow paths. A group of students including Bangha “Genesis” Song took 162 soil samples 5 centimeter deep from those areas and a non-contaminated control area. The current junior remembers the cold, wet days spent in the field and the long hours in the lab working under the encouragement of Smithson.

“It took a lot of dedication, but I was happy for the resilient habit that I developed in the course of the research," Song claims. "It was so exciting to see our results come out exactly as we speculated. ... The class was the most challenging I ever took here. ... However, I was happy because nothing good comes easy and anything that is gotten easily can easily be lost.”

After all the data was gathered, Smithson’s students were able to approach Panciera with definitive results that showed exactly where the overflow was taking place. Agriculture faculty then set about solving the problem. “This evidence was a key part of our solution,” the professor states. New pumping equipment was acquired and other solutions sought.

“Paul’s class was an excellent example of using science to solve problems. The full potential of hands-on learning is best realized when it can be applied to solving a real world problem,” explains Panciera.

Finally, Smithson detailed a summer student research project analyzing Berea drinking water for disinfection byproducts. Taken from several spring-fed bodies of water, Smithson says the city’s water is generally very clean, especially when compared to other cities. However, high levels of chlorination byproducts have been routinely detected in mid-to-late summer. Since the byproducts are suspected carcinogens, measures have to be taken by local utility workers to make sure the levels stay within acceptable levels.

Local professionals suspected the problem originated with the growth of algae bloom in late summer when the water levels drop. “They believed algae grows and rots and new dissolved organic matter becomes a precursor for byproducts to form,” explains Smithson. His research students, which included current junior Laxman Gurung, took samples from the various sources and tested them for chlorophyll, nutrients and trihalomethane (THM) potential. (THM is a suspected carcinogen.) They then added sodium hypochlorite (Clorox) to each sample, let them stand a week and then retested them for THMs.

It was the Gurung's first research project and introduced him to basic scientific methods and how they apply to practical problem solving. “The field trips were not only nice breaks in between the lab hours, but also reminded us how what we were dong in the lab was not some fancy research cut off from the real world, but the one that was directly related to the community in Berea.”

The group concluded that nitrate in the water stimulates algae growth and as they grow, the nitrate declines and then the algae die and decay. Also, the chlorophyll and THM formation flowed in similar patterns. This information allowed them to form a hypothesis that could easily be tested in the future.

“I liked the challenge of working on a problem for which we didn’t have the answer,” recalls Gurung. "I know that had I been at some big university, it would have been rare, if not impossible, to get to do research right after the first year in college. ... This is a great opportunity we have here at Berea College and I have benefited a lot from it.”

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