The green machine: Algae clean wastewater, convert to biodiesel

Feb 17, 2011

Let algae do the dirty work. Researchers at Rochester Institute of Technology are developing biodiesel from microalgae grown in wastewater. The project is doubly "green" because algae consume nitrates and phosphates and reduce bacteria and toxins in the water. The end result: clean wastewater and stock for a promising biofuel.

The purified can be channeled back into receiving bodies of water at treatment plants, while the can fuel buses, construction vehicles and farm equipment. Algae could replace diesel's telltale black puffs of exhaust with cleaner emissions low in the sulfur and particulates that accompany .

Algae have a lot of advantages. They are cheaper and faster to grow than corn, which requires nutrient-rich soil, and . Factor in the fuel used to harvest and transport corn and starts to look complicated.

In contrast, algae are much simpler organisms. They use to convert sunlight into energy. They need only water—ponds or tanks to grow in—sunlight and carbon dioxide.

"Algae—as a renewable feedstock—grow a lot quicker than crops of corn or soybeans," says Eric Lannan, who is working on his master's degree in mechanical engineering at RIT. "We can start a new batch of algae about every seven days. It's a more continuous source that could offset 50 percent of our total gas use for equipment that uses diesel."

Cold weather is an issue for biodiesel fuels.

"The one big drawback is that biodiesel does freeze at a higher temperature," says Jeff Lodge, associate professor of biological sciences at RIT. "It doesn't matter what kind of diesel fuel you have, if it gets too cold, the engine's not starting. It gels up. It's possible to blend various types of biodiesel—algae derived with soybeans or some other type—to generate a biodiesel with a more favorable pour point that flows easily."

Lannan's graduate research in biofuels led him to Lodge's biology lab. With the help of chemistry major Emily Young, they isolated and extracted valuable fats, or lipids, algae produce and yielded tiny amounts of a golden-colored biodiesel. They are growing the alga strain Scenedesmus, a single-cell organism, using wastewater from the Frank E. Van Lare Wastewater Treatment Plant in Irondequoit, N.Y.

"It's key to what we're doing here," Lodge says. "Algae will take out all the ammonia—99 percent—88 percent of the nitrate and 99 percent of the phosphate from the wastewater — all those nutrients you worry about dumping into the receiving water. In three to five days, pathogens are gone. We've got data to show that the coliform counts are dramatically reduced below the level that's allowed to go out into Lake Ontario."

Lodge and Lannan ramped up their algae production from 30 gallons of wastewater in a lab at RIT to 100 gallons in a 4-foot-by-7-foot long tank at Environmental Energy Technologies, an RIT spinoff. Lannan's graduate thesis advisor Ali Ogut, professor of mechanical engineering, is the company's president and CTO. In the spring, the researchers will build a mobile greenhouse at the Irondequoit wastewater treatment plant and scale up production to as much as 1,000 gallons of wastewater.

Northern Biodiesel, located in Wayne County, will purify the lipids from the and convert them into biodiesel for the RIT researchers.

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User comments : 6

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apex01
not rated yet Feb 17, 2011
at what cost? $30.00 a gallon. DARPA says they have it down to $3.00 a gallon.
Sanescience
not rated yet Feb 17, 2011
*THAT* is a future for energy you can "believe" in.
stealthc
not rated yet Feb 17, 2011
algae reproduces, and sunlight is free, wtf?
Sanescience
5 / 5 (1) Feb 17, 2011
There will be some initial equipment fee, but sewage treatment is not free either, so technically you just sell at market price and mitigate some of the cost of the sewage plant.

Ultimately there will be algae and yeast strains that accepts all kinds of waste streams from agriculture and sewage. Purpose grown switch grass that is GM to reduce ligand content and increase fuel production is also in the news.

And before the fuel vs. food fears start being voiced, potentially this could lower food cost. If a farmer can supplement grain sales by converting unused portions(for corn that would be the stocks, leaves, and cobs) to produce an energy product that cuts his costs or even supplements his income, he can sell his grain at more competitive prices.
StandingBear
not rated yet Feb 18, 2011
I like this technology. This is good old American, with friends, engineering and discovery at its best. Keep up the good work guys. I want to be there when you dedicate the plant outside New York City that processes five hundred million gallons per hour of NYC sanitary flow. I drive a diesel RV that would love to use some of your product. Especially nice if you locate one outside Los Angeles to take care of fifty billion gallons per day....producing millions and millions of gallons of diesel and lowering the price of it, cutting out the importers.
Trim
1 / 5 (1) Feb 18, 2011
What happens to the algae? Its mass must increase. Can it be used as an animal feed or put on land as an organic fertiliser?

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