Energy has almost always been about oil. Now, things are changing.
The answer might lie in pond scum.
Algae’s ability to become biofuels has captured many imaginations, civil and environmental engineering professor Tryg Lundquist said. Cal Poly’s Algae Technology Group, run by Lundquist and chemistry professor Corinne Lehr, received a $1.3 million grant from the Department of Energy this past spring to carry out research on algae biofuel over a three-year period.
The Cal Poly group focuses on growing algae for biofuels with wastewater. This way, the algae treat the wastewater as well.
“So it’s kind of a twofer situation, which really helps the economics of the algae biofuel,” he said.
This method uses less electricity than the current methods of treating wastewater. Also, the algae systems are less expensive to build than a conventional wastewater treatment facility.
On any Wednesday afternoon, Engineering IV (building 192), room 201 is bustling with students wearing goggles and protective lab gear. The fluorescent lights reflect off glass tubes filled with green sludge. An ominous silver instrument that looks like a type of probing device sits on a desk nearest the back door. One long desk at the front of the room by the dry-erase board is covered with backpacks and jackets. The students don’t take their personal belongings with them to their workstations: The desks are covered with wastewater — otherwise known as “poop-water.”
Civil and environmental engineering graduate student Mike Chang is researching the conversion of wastewater to energy. He works on growing algae as cheaply as possible and recycling nutrients as many times as possible.
Currently, wastewater is treated using only bacteria, which require oxygen. The oxygen is supplied by electric blowers pumping air through the wastewater so the bacteria can grow and absorb nutrients.
The Cal Poly research team is using algae instead of the blowers. The algae take in carbon dioxide from the bacteria and release oxygen for the bacteria. Both organisms use nutrients from the water.
“The main benefit is it costs less energy,” Chang said.
Justin Kraetsch, a civil and environmental engineering graduate student, also works in this area. He focuses more on removing nutrients — nitrogen, phosphorous and potassium — from the wastewater. Nitrogen is particularly harmful to ecosystems and can’t be discharged.
“It’s like dumping fertilizer in a creek,” Kraetsch said.
The samples of algae come from a pilot plant at San Luis Obispo’s water treatment facility, where the group has three sets of three ponds. According to Kraetsch, they use the ponds to treat wastewater for their research (not for whole city) and collect samples once a week.
The treated water isn’t for drinking, Kraetsch said, but for irrigation.
The water treatment facility treats approximately 4 million gallons per day, or about 90 gallons per resident, according to Lundquist. Cal Poly’s pilot plant treats approximately 8,000 gallons per day.
“We’re like just a drop in the bucket for them,” Chang said.
Algae into biofuel
Two fuels can be made from algae: liquid transportation biodiesel and methane. Approximately 10,000 people worldwide are working on this research, Lundquist said.
But you can’t fill your gas tank yet with it just yet, and you probably won’t be able to anytime soon. That’s because making algae into biofuels can be a tricky process.
Under certain conditions, humans will store energy as fat. Algae will do that as well, Chang said, and they’ll make little pockets of energy called lipids. The algae are broken up and the energy is taken out and used to create the biodiesel.
This process involves sonicators, solvents, centrifuges and transesterification.
“Basically you do magic to it, and it becomes biodiesel,” Chang said.
Other methods include anaerobic digestion, and a colony of bacteria known as methanogens: naturally occurring bacteria that produce methane and carbon dioxide.
“The methanogens go to town on the broken algae cells and release methane and you can use that methane as a fuel,” Chang said.
Currently, when someone says “biofuel” most people think of ethanol from corn, Lundquist said. That, however, often leads to a food-vs.-fuel debate.
“Algae grown on wastewater is not a food, luckily,” he said. “So we are free to grow that and convert into fuel without anybody accusing us of stealing food or creating higher food prices worldwide.”
Other benefits of biofules include renewable energy and fewer carbon emissions.
Unfortunately, this project can’t be done everywhere. To produce algae on a commercial scale, you need ample and inexpensive land, water and lots of sun.
When it comes to biodiesel, the fuel is not compatible with older engines and most new cars aren’t designed for it.
“We’re working on all these issues,” Chang said. “There’s a lot of research going into all these things.”
Can it compete?
Because it’s a research project, Lundquist wouldn’t say there are controversial opinions to the method. But there are open questions.
Can someone, for instance, grow enough algae of high enough quality to make the biofuel competitive with fossil fuels?
Lundquist said that’s challenging because fossil fuels only require a well and some refining, which is much less costly than growing a crop and then converting it into biofuel.
“Basically, if people want to be sustainable and use biofuels, they should expect to pay more,” he said.
Algae could produce millions of barrels of transportation fuel each year. That amount pales, however, in comparison to the approximately 220 billion gallons of transportation fuel Americans consume each year, Lundquist said.
This interdisciplinary research project includes students from diverse educational backgrounds: environmental engineering, bioresource and agricultural engineering, electrical engineering, food science, animal science and others.
The research the Cal Poly group is conducting has many advantages. First, the water they use is wastewater, not something people or animals need to drink. The nutrients in that water make good algae fertilizers, which the group obtains for free. Also, the group is simultaneously treating the water through this process.
“This is a drumbeat we’ve been pounding for many years,” Lundquist said. “We’re providing an additional service.”