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Civil engineering undergrad seeks a way to turn invasive plant into valuable fertilizer

Baylee Demuth | Oct 28, 2019
Photos provided

Civil engineering undergrad seeks a way to turn invasive plant into valuable fertilizer

Baylee Demuth | Oct 28, 2019

Photos provided

Garrett Dildine’s passion for aquatic life stems from being raised by a family of fishermen. He grew up accompanying his father and grandfather on countless fishing trips. At Ohio University, he found an opportunity to blend his environmental interests with his engineering studies.

A senior studying civil engineering in the Russ College of Engineering and Technology, and environmental studies in the Honors Tutorial College (HTC), Dildine is studying how to turn hydrilla verticillata, an invasive freshwater plant,  into something useful by making it into a liquid fertilizer.

“I looked at making biochar from aquatic plants, but that didn’t really work,” said Dildine, whose research is funded by Russ Vision Funds for undergraduate research, and the HTC. “So eventually I received a grant to try and make liquid seaweed extract instead from hydrilla.”

Dildine works alongside Professor and Department Chair of Civil Engineering Guy Riefler. Riefler, who has advised on several sampling and testing techniques, credits Dildine for being self-directed and capable of building experimental procedures and an apparatus on his own.

“Garrett has a strong environmental and sustainability ethic,” Riefler said. “With this work, he is attempting to take a nuisance organism and create a beneficial use for it.  This approach to environmental restoration by finding economic value in the problem can have a significant and lasting impact on damaged sites.”

After receiving collecting and cultivating permits from the Ohio Department of Natural Resources and Ohio Department of Agriculture, Dildine collected large quantities of the plant in August at local Dow Lake, part of Strouds Run State Park, to mass produce hydrilla-based fertilizer prototypes. 

Since then, he has already created three prototypes, which are now being analyzed by Ward Laboratories in Nebraska. The first fertilizer is a dry meal made by washing, drying and milling hydrilla into a fine powder. The second is a synthetic alkali extraction, created using increased pressure, temperatures of up to 120°C, and sodium hydroxide or potassium hydroxide to catalyze the extraction of the dry meal. The third is a non-synthetic extraction made by soaking the dry meal in ultrapure water and separating the solids using centrifugation, or spinning. 

Dildine plans to conduct liquid chromatography-mass spectrometry to determine the different hormones that are in the extracts. There are three hormones commonly reported in liquid seaweed extracts, including auxins, gibberellins and cytokinins.

“The hypothesis here is that we’ll find those hormones in hydrilla as well, which is the benefit of using liquid seaweed extracts,” Dildine said. “If we find them in hydrilla, then we can make the case that yes, hydrilla-based extracts are just as valuable as seaweed-based extracts.”

No matter the results of the prototype analysis, Dildine is excited to experiment with the invasive plant and learn more about its uses.

“I’m hopeful, but you never know,” Dildine said. “There’s lots of directions we can go with it if it doesn’t work out as a fertilizer.”

Marissa McDaid and Colleen Carow contributed to this story.