Scale Up


OMEGA San Francisco

NASA’s OMEGA Program at a Crossroads

September 5, 2012, by Jonathan Trent
AlgaeIndustryMagazine.com

Biofuels are my passion, but they have had rather bad press, from complaints about displacing food production to the inefficiency of soybeans and the carbon footprint of ethanol. Microalgae have a low profile but they deserve a much higher one, since the fossil oil we mine mostly comes from microalgae that lived in shallow seas millions of years ago – and they may be key to developing sustainable alternative fuels.

But there are big unsolved problems at which governments should be throwing funds and brainpower as if we were involved in a Manhattan project. For example, since few species of microalgae have been domesticated, we don’t know how to grow them reproducibly or economically. At what scale will algae farming be efficient?

Luckily, there may be a good way to cultivate algae while solving the ethical problem of producing biofuel, and without competing with agriculture. Freshwater algae can be grown in wastewater (effectively, water with fertilizer), or marine algae can be grown in a blend of seawater and wastewater. In both cases, wastewater provides a growth medium and the algae clean the wastewater by removing nutrients and pollutants from it. So there’s no competition for fresh water needed elsewhere, no reliance on synthetic fertilizer, and the environment benefits.

The United Nations estimates that the world produces around 1,500 cubic kilometers of wastewater annually, of which more than 80 percent is untreated. This means there is an ample supply of nutrient-rich water for the algae, while algae treatment is available to offset the environmental impact of wastewater.

“Now, with funds running out and NASA keen to spin off OMEGA, we need the right half-hectare site for a scaled-up demonstration.”

There remains the question of how and where to grow the algae. Raceways are relatively inexpensive, but need flat land, have lower yields than PBRs and problems with contamination and water loss from evaporation. PBRs have no problems with contamination or evaporation, but algae need light, and where there is light, there is heat: A sealed PBR may cook, rather than grow, algae. And mixing, circulating, and cleaning problems can send costs sky high.

Assuming we can fix these issues, the question of siting remains. In order not to compete with agriculture, algae cultivation must use non-arable land reasonably close to a wastewater treatment plant. But in most cities, wastewater plants are surrounded by infrastructure, so cultivation around the plants would affect roads, buildings, and bridges—again driving up costs prohibitively.

Enter the OMEGA Solution

A solution occurred to me: For coastal cities, we should try a system I call OMEGA: Offshore Membrane Enclosures for Growing Algae. Some 40 to 60 percent of Earth’s population lives near a coast, most of the biggest cities are near a coast, and nearly all coastal cities discharge wastewater offshore.

OMEGA uses PBRs made from cheap, flexible plastic tubes floating offshore, and filled with wastewater, to grow freshwater, oil-producing algae. It would be easier to build the systems in protected bays, but breakwaters could also be constructed to control waves and strong currents. The water need not be deep or navigable, but a few things are crucial, including temperature, light, water clarity, frequency and severity of storms, boat traffic, nature and wildlife conservation.

OMEGA System

Illustration of OMEGA’s implementation at San Francisco’s wastewater treatment plant

Beyond solving the problem of proximity to wastewater plants, there are other advantages to being offshore. OMEGA uses buoyancy, which can be easily manipulated, to move the system up and down, influencing exposure to surface waves and adjusting light levels. And the overheating problem is eliminated by the heat capacity of the surrounding seawater.

The salt gradient between seawater and wastewater can also be exploited to drive forward osmosis. Using a semipermeable membrane, which allows water, but not salt, pollutants, or algae to pass through, wastewater is drawn into the saltwater with no added energy. In the process, algae are concentrated in preparation for harvesting and the wastewater is cleaned, first by the algae, and then by forward osmosis. This produces water clean enough to release into the marine environment or recover for reuse.

If OMEGA’s freshwater algae are accidently released, they die in seawater, so no invasive species can escape into the ecosystem. In fact, OMEGA can improve conditions by providing a large surface for seaweed and invertebrates to colonize: part floating reef, part floating wetland. Then there are the extra possibilities of developing wind or wave power and aquaculture, growing food such as mussels.

Flash to the Present

OK, if it’s so good, where is it? For the past two years, backed by NASA and the California Energy Commission, and about $11 million, we have crawled over every aspect of OMEGA. In Santa Cruz, Calif., we built and tested small-scale PBRs in seawater tanks. We studied OMEGA processing wastewater in San Francisco, and we investigated biofouling and the impact on marine life at the Moss Landing Marine Laboratories in Monterey Bay.

“We could be on the threshold of a crucial transition in human history – from hunting and gathering our energy to growing it sustainably.”

I’m now pretty confident we can deal with the biological, engineering, and environmental issues. So will it fly economically? Of the options we tested, the OMEGA system combined with renewable energy sources – wind, solar, and wave technologies – and aquaculture looks most promising.

Now, with funds running out and NASA keen to spin off OMEGA, we need the right half-hectare site for a scaled-up demonstration. While there is enthusiasm and great potential sites in places ranging from Saudi Arabia to New Zealand, Australia to Norway, Guantanamo Bay to South Korea, as yet no one has committed to the first ocean deployment.

We could be on the threshold of a crucial transition in human history—from hunting and gathering our energy to growing it sustainably. But that means getting serious about every option, from alpha to OMEGA.

Read more in New Scientist.

More Like This…

HOME Algae Industry Jobs

Copyright ©2010-2012 AlgaeIndustryMagazine.com. All rights reserved. Permission granted to reprint this article in its entirety. Must include copyright statement and live hyperlinks. Contact editorial@algaeindustrymagazine.com. A.I.M. accepts unsolicited manuscripts for consideration, and takes no responsibility for the validity of claims made in submitted editorial.

From The A.I.M. Archives

— Refresh Page for More Choices
Biomass abounds on Earth, as forests, fields, sewage and seaweed. But only a small fraction, mostly human or agricultural waste, can be harvested without posing environme...
Algae.Tec Ltd has received its first purchase order from Reliance Industrial Investments and Holdings Limited (RIIHL), in connection with the arrangements announced on Ja...
Although the use of whole microalgae in animal diets has long been studied, the 
de-fatted biomass of microalgal species, derived from biofuel production research, has on...
In Phys.Org, Yu Yonehara notes the breakthrough research from the Tokyo Institute of Technology on the connection between early marine algae and the development of terres...
A new, outdoor system at the University of Dayton Research Institute has been producing a high volume of algae since its installation in the summer of 2013, even through ...
Kazuaki Nagata reports from Japan that while the Fukushima nuclear disaster has prompted vigorous discussion about alternative energy in Japan, there is a lack of a paral...
A University of New South Wales (UNSW)-led team of researchers has discovered how algae that survive in very low levels of light are able to switch on and off a weird qua...
Gilbert, AZ-based Heliae has announced a partnership with Sincere Corporation, a Japanese waste management and recycling company, to form a joint venture and develop a co...
Starting in the early 70s, agencies in the former USSR invested more than 20,000 person-years of research and development to produce Bio-Algae Concentrates (BAC) that hel...
A recent discovery in the multicellular green alga, Volvox carteri,has revealed the origin of male and female sexes, showing how they evolved from a more primitive mating...
The EPA has released the Annual Use of Pesticides in the U.S. Report. We now know that American farmers apply roughly a billion pounds of toxic chemicals intentionally in...
Researchers at the Paul Scherer Institute (PSI) in Wädenswil, Switzerland, have succeeded in producing energy-rich gas from microalgae, and in doing so have demonstrated ...
Biplab Das reports in NatureAsia.com that a research team has found aqueous extracts of the marine brown algae Lobophoro variegate that can inhibit the replication of hum...
Analia Murias 
reports for fis.com that Chilean exports of products made from macroalgae generated a total of $195 million US in the first seven months of 2014, according...
U.S. farmers and biofuels makers are watching for the Environmental Protection Agency’s (EPA’s) final decision on the 2014 Renewable Fuel Standard rules, which will set t...
James “Jamie” Levine took over the reigns at Sapphire Energy in July of this year as former President and CEO Cynthia “CJ” Warner stepped down, retaining her role as chai...
With their new CO₂ processing-platform called AstaCos, AlgaeBiotech can produce waxy particles of only 50-100 µm in size with a loading of 25% astaxanthin oleoresin. The ...
A team of Michigan State University algae researchers have discovered a cellular "snooze button" that has the potential to improve biofuel production and offer ...