The Good, The Bad and the Algae

Georgia Southern Professors Explore Multiple Uses for the Oft-maligned Renewable Resource

Is algae good or bad?

It’s a question most people don’t think to ask. After all, when algae accumulates on the outside of your house, or in containers left outside, or in your swimming pool, you just get rid of it.

There’s something worse than common household algae, however, and more harmful. They’re called algal blooms that form in bodies of water. The largest of these is called “The Dead Zone,” a mass of water more than 6,300 square miles that sits in the Gulf of Mexico. It’s “dead” because the water is hypoxic, with oxygen levels so low that it can’t sustain life.

Algal blooms happen when the chemicals from agricultural runoff and wastewater from urban areas flood bodies of water with nutrients like nitrogen and potassium on which algae feed. The algae consumes all these nutrients, growing and growing until the nutrients run out. Then the bloom collapses and dies, sucking all the oxygen from the water in the process. These blooms can cause massive fish kills, create toxins that cause sickness and death in humans, raise treatment costs for drinking water, and hurt industries that depend on clean water to operate.

So what’s good about algae?

Georgia Southern biology professors Anthony Siccardi, Ph.D., and John Carroll, Ph.D., are researching all the good ways this oft-maligned substance can potentially be used to solve some of our more pressing environmental problems.

“I mean, it is complicated because the algae that cause these blooms are primarily phytoplankton, and those are really important,” said Carroll. “That’s the base of the marine food web. And so it’s not that the algae itself is bad, it’s when there’s an overgrowth of it.”

Carroll and Siccardi are serving as co-principal investigators on a project with the Sandia National Laboratory, under contract with the U.S. Department of Energy, to find out how to use algae grown on algal turf scrubbers to create biomass that is usable for biofuel.

An algal turf scrubber is a ramp covered with artificial turf or some other kind of rough surface. Using a pump, water is pulled from a water source and pulsed down the ramp, where algae begins to grow on the turf. When the algae has grown substantially, it is harvested and the process starts over again.

Siccardi says the process isn’t just about harvesting algae, however. It actually purifies the water, too.

“Let’s say you have a river that’s polluted with excess nutrients like excess phosphorus or excess nitrogen,” said Siccardi. “The algae are able to sequester those nutrients into the algal biomass, removing it from the water column. And then you can take that algal biomass and convert that to biofuel.”

Siccardi and Carroll are part of a network of several researchers around the country who are working together with Sandia to refine the algae growth process. They’ve tried different types of surfaces and flow rates in their research. Sandia will then take the harvested biomass and see which specimens work best for biofuel, which is not only a more sustainable fuel source, but also burns cleaner than petroleum-based fuel.

Grad student Emily Wells prepares algae samples.

The technology promises an exciting future, but there is still a long way to go.

“Right now the key is cost,” said Siccardi. “The cost is still higher than you would normally pay for fossil fuels out of the ground. Each year, the price of a gallon of biofuel comes down a little bit as different advancements are made.”

In addition to their work with Sandia, Carroll and Siccardi are looking for other ways to use the harvested algae. Because algal turf scrubbers can be so beneficial to the environment, the question is how to scale their use.

“If this is going to be a scalable thing, if we’re going to say you can use these turf scrubbers to remove nutrients and then you can make things out of the biomass, it needs to make sense,” said Carroll. “If there are too many steps to use it, then people aren’t going to use it. And then what happens is that biomass just gets thrown back into the dump. So those nutrients just get back into the system. So I’m interested in, ‘What are we going to do with this stuff now that we have it?’”

The professors are working with their colleague Jennifer Zettler, Ph.D., in the biology department as well as Casey Schachner and Jason McCoy in the art department to use the algae in kiln-fired ceramics. By drying the algae and then grinding it into a powder, they incorporated it into clay and created small structures, one of which Zettler now has on her desk. They also hope to test the durability and resilience of the clay to use as a structure on which to grow oysters which eat algae and can help control algal blooms.

Siccardi and his graduate student Michelle Lowery are also working with the Sustainable Aquaponics Research Center on the Armstrong Campus, which combines raising fish with hydroponics to produce plants. They are using algal turf scrubbers to remove excess nutrients from the system water, and then harvesting the algae. The algae can then be used as a soil additive, or it can be fed to black soldier flies, whose larvae can be fed back to the fish.

“When you look at some of these aquaculture facilities where they have a lot of animals in a small pond or tank, and then you’re putting all this feed in and you have excess feed, and some of the animals die — all of that is releasing nutrients into the environment,” he said. “And then when they harvest, they typically just drain down the pond and that water winds up getting dumped into a river or a lake or a stream or the ocean. It causes a lot of environmental problems. So I’ve always seen this as a way to capture those excess nutrients and convert those excess nutrients into this algal biomass that you can then use for a whole host of
other things.”

The professors are working on grants to pursue their ideas using turf scrubbers and biomass. Siccardi says the simplicity of the process and its impact on the environment make him excited about the future.

John Carroll, Ph.D., Anthony Siccardi, Ph.D., and grad students Christopher Lee and Emily Wells work with the algal turf scrubber at the Priest Landing site.

“I just think that’s so cool to be able to recycle all of those nutrients in an extremely sustainable way,” he said. “These are the types of things that could be easily transferred to other countries that maybe don’t have access to a lot of the technology the U.S. has. It’s literally open to anybody.”
– Doy Cave