UH Hilo researchers designing sustainable wastewater systems for local industries

Professor of Applied Engineering Shihwu Sung believes Hawaiʻi Island is a prime location for this type of research.

By Jamie Josephson.
This story is part of a series on curriculum and projects at UH Hilo focusing on sustainability issues.

Shihwu Sung
Shihwu Sung

Many researchers at the University of Hawaiʻi at Hilo are committed to the environment and are doing their part to help Hawaiʻi Island industries utilize more renewable and sustainable energy sources. Research into sustainable energy is an ever-growing field with plenty of space for innovation.

Shihwu Sung, professor of applied engineering at UH Hilo, is currently conducting research on converting waste into biodiesel energy. The research project is Sung’s primary focus since he was hired as coordinator of the university’s energy engineering program in 2014 fresh from a prestigious position at Iowa State University.

Learn more about Sung’s background:

“I’ve always been very interested in the environment,” Sung says. “Through my research I want to focus on decreasing the amount of fossil fuels used, and increasing the amount of renewable energies on Hawaiʻi Island.”

Sung’s research is currently being conducted in the Renewable Energy Lab on the UH Hilo campus, where he has built a lab scale of an upflow anaerobic sludge blanket (UASB) reactor, a single tank wastewater treatment system.

The project is funded by and in conjunction with Big Island Biodiesel, a Keaʻau based plant committed to “a sustainable, community-based vision.”

Aerial of biodeisel plant
The Big Island Biodeisel plant, located in Keaʻau, opened in 2012.

The research

Tubes with organic matter in lab.
​Shihwu Sung’s model showing the fermentation process. ​Renewable Energy Lab, UH Hilo, Oct. 2017.

“This UASB reactor machine starts with wastewater, undergoes processes of conversion, and ultimately produces a biogas that contains methane,” Sung explains. “The produced biogas can then be used as a primary source of energy.”

The wastewater that goes into the reactor is an organic product, containing natural carbons. The carbons break down through the use of anaerobic organisms, which, through a continuous upward flow, creates biogas.

“The lab scale UASB reactor was created to test the method on a smaller scale and determine if this process is compatible for the Big Island,” says Sung. “We also have a pilot scale at the biodiesel plant, and eventually, we will have a full scale UASB reactor.”

Chayanon Sawatdeenarunat, who received his doctor of philosophy in molecular biosciences and bioengineering from UH Mānoa in 2017, is now a postdoctoral researcher on this project. He previously worked on a biorefinery and biorenewable energy project at UH Mānoa, and before that on biodiesel engineering with Sung at Iowa State. He has since moved to Hilo to be involved in Sung’s research.

He emphasizes the universality of waste conversion technologies.

“It can be used in practically any industry, any company that uses a lot of energy can make use of this technology and turn their waste into fuel, becoming more sustainable,” he says.

He continues, “This is the first waste to energy conversion process being researched on the Big Island. It is good for the island, and we are able to continue our research because the people of Hawaiʻi have their own environmental concerns.”

Clear procssed water in a flask in the lab.
​Processed wastewater from Sung’s model in the lab.

Sung believes that Hawaiʻi Island is a prime location for this type of research.

“We need biofuel here, because, well, the energy practices are not very good right now,” he says. “Creating more sources of renewable energy and technologies of waste conversion will help Hawaiʻi become more independent. Everyone should believe in this idea.”

The pilot scale model of the UASB reactor is located in Keaʻau at Big Island Biodiesel, a branch of Pacific Biodiesel, a company that converts used cooking oil and grease into biodiesel fuel. If the pilot scale reactor proves to work in its intended environment, the full scale model will allow the plant to convert its waste products into biogas, which will supplement the energy needs of the plant.

“This technology will help us fulfill our overall goal of being a zero-waste facility,” says Douglas Olds, a researcher at Big Island Biodiesel.

Helping local coffee mills become more sustainable

Sung and Sawatdeenarunat are also working with local coffee mills to help an already waste-filled industry become more sustainable. Essentially, it is the same idea. Waste to energy conversion allows the mills to reduce waste, while introducing more renewable energies into their product.

Rows of coffee trees
Coffee farm in Kona. Wikimedia.

Instead of using typical waste water, coffee industries would use the byproduct of the coffee production process, the fruit of the coffee plant itself. As the fruit contains organic carbon, the process remains the same, creating a biogas, which could be used as energy to fuel production processes.

Sung likes helping the community of Hawaiʻi Island.

“This project would help individual business owners save money in the long-term by becoming more sustainable, which hopefully would boost the economy of the island,” he says. “Also, we would be helping the environment by reducing the amount of non-renewable energies currently in use.”

About the author of this story: Jamie Josephson (senior, English) is a public information intern in the Office of the Chancellor.

-UH Hilo Stories

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UH Hilo takes first steps toward a Certificate in Sustainability program

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