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Energy From Algae

Algae bioreactor

The quest for inexpensive, renewable, clean energy has become a metaphorical Holy Grail for scientists and engineers the world over. At Ohio Northern, a team of senior mechanical engineering students accepted the challenge in a way that took the concept of green energy to a whole new level.

Alternative energy is produced from many sources. In fact, ONU’s campus currently utilizes three of the most common forms of renewable energy —wind, solar and geothermal. But engineering students Evan Iles of Wadsworth, Ohio, Peter Langenkamp of Coldwater, Ohio, Jeff Schulte of Genoa, Ohio, and Nate Gannon of Ada, Ohio, used their senior capstone research project to explore another form— algae.

Algae can be used to make organic alternatives to fossil fuels. Through photosynthesis, algae converts carbon dioxide into oil, which can then be refined into combustible biofuels. Algae occurs naturally all over the world in ponds, rivers and oceans, but the capstone team set out to develop the best possible environment for multiple species of algae to grow in the form of a multispecies algae bioreactor.

The bioreactor is a 500-gallon tank that simulates a naturally occurring pond. Advisor Dr. Robert Verb, a professor in ONU’s biology department, helped the team understand the ecology of natural ponds, while engineering professors Drs. Eric Baumgartner and Hui Shen guided the students in building the bioreactor.

“My role was to assist the students in building a functional knowledge base as it related to different types of algae, where they grow, and the variables —light, nutrients, temperature etc.— they require for optimal growth,” said Verb.

PVC pipes were used to replicate plant stalks, which provide support for algae colonies to form. The team studied how the various types of algae, commonly referred to as “floaters, sinkers and grabbers,” formed in the bioreactor. The tank was filled with a combination of freshwater and wastewater from the Ada wastewater plant, which provided nutrients to the algae. An added benefit of using algae for an energy source is its ability to recycle organic waste material.

Growing algae is only the first step in the process. Harvesting the tiny green plants is not easy. In fact, the first filtration process used by the team didn’t work. Eventually they were able to separate enough algae from a measured amount of water and dry it to calculate the amount of algae their bioreactor was producing.

By far, the most difficult part of the project was keeping expenses down. The reason of growing multiple species of algae, rather than a single “high lipid” or oil-producing strain is lower costs. Most current research, team members say, involves growing a single high lipid strain that requires expensive, highly controlled scientific environments.

By focusing on multiple species, the team believes that less money, time and energy can be used to produce a large amount of the raw product. The team hopes future capstone teams will continue where they left off to refine the multispecies algae bioreactor into a viable energy producer.