NASA scientists have proposed an ingenious and remarkably resourceful process to produce “clean energy” biofuels, that cleans waste water, removes carbon dioxide from the air, retains important nutrients, and does not compete with agriculture for land or freshwater. As a clean energy alternative, NASA invented a bioreactor that is an Offshore Membrane Enclosure for Growing Algae (OMEGA), an algae photo-bioreactor that grows algae in municipal wastewater to produce biofuel and a variety of other products.

NASA plans to refine and integrate the technology into biorefineries to produce renewable energy products, including diesel and jet fuel.

OMEGA Project Overview Video

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The NLSI recorded this video of PI Jonathan Trent presenting the OMEGA project at NASA Ames Research Center in Moffett Field California. You can view the video by double clicking on the image above or you can download the file directly to your computer here. [324.2 MB .mp4 file; 0:58:10 run time]

The OMEGA system consists of large plastic bags with inserts of forward-osmosis membranes that grow freshwater algae in processed wastewater by photosynthesis. Using energy from the sun, the algae absorb carbon dioxide from the atmosphere and nutrients from the wastewater to produce biomass and oxygen. As the algae grow, the nutrients are contained in the enclosures, while the cleansed freshwater is released into the surrounding ocean through the forward-osmosis membranes.

“The OMEGA technology has transformational powers. It can convert sewage and carbon dioxide into abundant and inexpensive fuels,” said Matthew Atwood, president and founder of Algae Systems. “The technology is simple and scalable enough to create an inexpensive, local energy supply that also creates jobs to sustain it.”

When deployed in contaminated and “dead zone” coastal areas, this system may help remediate these zones by removing and utilizing the nutrients that cause them. The forward-osmosis membranes use relatively small amounts of external energy compared to the conventional methods of harvesting algae, which have an energy intensive de-watering process.

Potential benefits include oil production from the harvested algae, and conversion of municipal wastewater into clean water before it is released into the ocean. After the oil is extracted from the algae, the algal remains can be used to make fertilizer, animal feed, cosmetics, or other valuable products. This successful spinoff of NASA-derived technology will help support the commercial development of a new algae-based biofuels industry and wastewater treatment.

“The reason why algae are so interesting is because some of them produce lots of oil,” said Jonathan Trent, the lead research scientist at NASA Ames Research Center, Moffett Field, Calif. “In fact, most of the oil we are now getting out of the ground comes from algae that lived millions of years ago. Algae are still the best source of oil we know.”

Algae are similar to other plants in that they remove carbon dioxide from the atmosphere, produce oxygen as a by-product of photosynthesis, and use phosphates, nitrogen, and trace elements to grow and flourish. Unlike many plants, they produce fatty, lipid cells loaded with oil that can be used as fuel.

“The inspiration I had was to use offshore membrane enclosures to grow algae. We’re going to deploy a large plastic bag in the ocean, and fill it with sewage. The algae use sewage to grow, and in the process of growing they clean up the sewage,” said Trent.

It is a simple, but elegant concept. The bag will be made of semi-permeable membranes that allow fresh water to flow out into the ocean, while retaining the algae and nutrients. The membranes are called “forward-osmosis membranes.” NASA is testing these membranes for recycling dirty water on future long-duration space missions. They are normal membranes that allow the water to run one way. With salt water on the outside and fresh water on the inside, the membrane prevents the salt from diluting the fresh water. It’s a natural process, where large amounts of fresh water flow into the sea.

Floating on the ocean’s surface, the inexpensive plastic bags will be collecting solar energy as the algae inside produce oxygen by photosynthesis. The algae will feed on the nutrients in the sewage, growing rich, fatty cells. Through osmosis, the bag will absorb carbon dioxide from the air, and release oxygen and fresh water. The temperature will be controlled by the heat capacity of the ocean, and the ocean’s waves will keep the system mixed and active.

When the process is completed, biofuels will be made and sewage will be processed. For the first time, harmful sewage will no longer be dumped into the ocean. The algae and nutrients will be contained and collected in a bag. Not only will oil be produced, but nutrients will no longer be lost to the sea. According to Trent, the system ideally is fail proof. Even if the bag leaks, it won’t contaminate the local environment. The enclosed fresh water algae will die in the ocean.

The bags are expected to last two years, and will be recycled afterwards. The plastic material may be used as plastic mulch, or possibly as a solid amendment in fields to retain moisture.

When astronauts go into space, they must bring everything they need to survive. Living quarters on a spaceship require careful planning and management of limited resources.
“We have to remember,” Trent said, quoting Marshall McLuhan: “we are not passengers on spaceship Earth, we are the crew.”

Teague Soderman of the NASA Lunar Science Institute had the opportunity to talk with Trent about the OMEGA project in the context of NASA space exploration. Listen to a short audio podcast here [11:53 min-- 120 MB .wav file].

For more information about OMEGA, visit:

http://www.nasa.gov/centers/ames/research/OMEGA/index.html

Posted by: Soderman/NLSI Staff
Source: NASA

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