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
Hammenhög, Sweden-based agribusiness Simris Alg has announced the launch of its first consumer products. The algae farmers’ exclusive omega-3 supplements and superfoods w...
K. S. Rajgopal writes in thehindu.com about a new study that demonstrates how macroalgal biomass from Gelidiella acerosa and Gracilaria dura collected from Adri and Verav...
None of us would be alive if sperm cells didn’t know how to swim, or if the cilia in our lungs couldn’t prevent fluid buildup. But we know very little about the dynamics ...
Sami Zaatari writes for the Middle East’s Gulf News that Abu Dhabi’s coastal sabkhas – the Arabic phonetic translation for salt flats – hold great potential for solar pow...
Five years ago, on April 20, 2010, an explosion on the Deepwater Horizon rig caused a release of 200 million gallons of oil into the Gulf of Mexico before the well was ca...
Scientific representatives from the EnAlgae consortium are announcing preliminary results this week from a key algal carbon capture project in the works at Britain’s larg...
Japan’s IHI Corporation has announced that they have succeeded in stably cultivating a modified high-output algal strain in a 1,500 square meter open pond in Kagoshima, K...
Rich McEachran writes in the Guardian that, in the process of surfacing a road, layers of asphalt – which is composed mostly of bitumen (a byproduct of crude oil distilla...
Joule has announced the issuance of a patent on the direct, continuous production of hydrocarbon fuels — extending its ability to target the highest-value molecules of th...
Using microalgae to capture CO2 is a complex process, especially in flue gas environments, reports an editorial by IEA Clean Coal Centre in worldcoal.com. There are many ...
Natacha Tatu writes in Worldcrunch about a 72-year old French chef who has taken on the challenge of bringing spirulina to the malnourished youth of the Central Africa. F...
EnAlgae researchers have published an economic model to help to explore the economics of cultivating macroalgae at sea. The model and report can be found here as outputs ...
OriginClear Inc. and partner AlgEternal have announced that, based on AlgEternal’s field tests, they believe their pure algae concentrate, harvested with OriginClear tech...
Studies conducted by EnAlgae partners in Ireland, France and Belgium point the way to seaweed being a viable and sustainable feedstock for the future in North West Europe...
Biocrude oil obtained from hydrothermal liquefaction (HTL) of algae can be an energy-efficient replacement for the fossil crude oil normally used in the production of fue...