ASA scientist – the inventor, heart, and soul of the OMEGA system (Offshore Membrane Enclosures for Growing Algae) – Dr. Jonathan Trent received his PhD in biological oceanography at Scripps Institution of Oceanography. He went on to post graduate work in Europe studying the biochemistry and molecular biology of microorganisms living in geothermal hot springs, the so-called “extremophiles.” He continued his work on extremophiles at Yale Medical School and discovered a class of proteins in these unusual organisms that is closely related to a class of proteins in humans.
Dr. Trent moved on from the medical school to Argonne National Lab where he studied environmental usages for extremophiles, mostly for cleaning up toxic wastes. He got involved with NASA shortly after they started a program in astrobiology in the late 90s. “It was a perfect job for me,” he says, “NASA was looking for people studying the most extreme organisms on this planet to understand if there could be life on other planets.”
Taking on the NASA job in 1998, he soon got involved in nanotechnology. “I basically was taking the robust molecules from extremophilic organisms and using their innate molecular recognition that allows them to self-assemble and using a bit of genetic engineering, we created some interesting structures and extremely tiny, devices.”
We spoke with Dr. Trent recently to get an update on where things are currently with the OMEGA project and his view of its, and our, future.
How did the OMEGA program get started at NASA?
One of the interesting projects of my nanotechnology group at NASA was self-assembling multi-enzyme arrays on a stable molecular scaffold we borrowed from an extremophile. One of the arrays we were working on was to improve the degradation of cellulose, using a variety of enzymes in that pathway. It was an interesting project and brought my attention to biofuels. You know there are two “holy grails” for biofuels, one is cellulose degradation and utilization and the other is microalgae. With my background in marine science, microalgae was a natural for me and I quickly dug into that literature. I realized almost immediately that one of the biggest hurdles for making algae into biofuels is the problem of scale and that’s what I wanted to address.
If you consider the scale of algae cultivation required to meet our current appetite for fuels and you put that in the context of the growing world population with food and water requirements, it is clear that whatever we do to make algae biofuels cannot compete with agriculture. For me this meant that we can’t use freshwater and we can’t use fertilizer, and in my view we can’t even use land. I don’t buy the argument about using the so-called non-arable land for algae cultivation, because if we made all the effort of transporting water and fertilizer to non-arable land to grow algae, why wouldn’t we make it arable land and start growing food on it?
I suppose if we were pumping seawater to the non-arable land it would be another story, but in general pumping water is energy intensive and not cost effective. In any case, back in 2008, thinking about all the problems associated with super-large-scale algae cultivation, I had the inspiration for Offshore Membrane Enclosures for Growing Algae (OMEGA). We’ve been working ever since then to prove or disprove the feasibility of this offshore approach.
Give us your elevator pitch on the OMEGA System.
Well, given that some species of microalgae are the fastest growing biomass on the planet and the best oil producers, we can probably agree that algae are the organism of choice for biofuels. If we further agree that biofuels production cannot compete with agriculture for freshwater or fertilizer, which means to me we have to use domestic wastewater to grow them, then let’s consider our options.
I think the fact that in all our coastal cities we already have the infrastructure for “disposing” of our wastewater offshore, we need to consider the possiblity of using this wasted water and the existing infrastructure for growing microalgae offshore. In addition to using wastewater from existing offshore outfalls for developing algae systems, there are other good reasons for OMEGA, I mean float photobioreactors (PBRs) in seawater. For example, there’s the heat-capacity of the seawater that can be used to control the temperature of the PBRs –temperature control of PBRs on land is a huge and expensive problem. The sea provides other energy savings also. Wave action can be used for mixing and the salt gradient can be used for forward osmosis, which not only cleans the wastewater released into the sea, it also concentrates the algae for harvesting.
If the freshwater algae cultivated in wastewater escape into the surrounding seawater they die (freshwater algae can’t survive in salt water), which means they will not become invasive species in our coastal waters. The OMEGA structure itself can be used as an enormous substrate for developing aquaculture to grow edible seaweeds, mussels, oysters, or some other marine “crop” appropriate for the local conditions.
If you see where this is going, OMEGA is a system of systems or an “ecology of technologies” – in which the concept of waste disappears: a waste product from one part of the system becomes a resource for another part. As far as possible the whole system, which includes the environment, is in balance.
In other words, we use algae to treat wastewater and wastewater to grow algae. We use carbon dioxide to grow algae and algae to sequester carbon dioxide. We use the inside of the OMEGA PBR to contain algae and the outside to produce aquaculture crops. We use the salinity gradient to prevent algae from becoming invasive species and to drive forward osmosis and to further clean the wastewater. We use solar energy, wave energy, and the heat capacity of the water. It’s all rather exciting and it’s very much like what NASA is developing for closed life-support systems for long-duration space exploration.
Well, I realize that was a long elevator pitch, but this is an important topic to consider on many levels of detail! I guess we’ll need a very tall building to do an elevator pitch for OMEGA!
So how far along is the project at this point?
The project was initially generously funded by the California Energy Commission, which was enough to get us started. And then by luck and serendipity I had a chance to present the OMEGA concept to Lori Garver, the Deputy Administrator of NASA. Lori immediately understood that not only was this technology an important spin-off from the kinds of closed life support systems that NASA has been developing for decades, but it is precisely the kind of technology that NASA gives back to society and to the world. Lori’s insight and understanding of the potential of OMEGA led to additional funding through the “Green Aviation” initiative at NASA.
Within a few months we completed Phase One, a 400-page paper study that considered possible materials and designs, hypothetical deployment locations and logistics, and estimates of energy return on investment, life-cycle analysis, etc. Based on Phase One results and an external review, we were encouraged to proceed with Phase Two, which is in progress and focuses on building and testing prototype PBRs as well as the OMEGA system components in the lab and in seawater tanks.
Phase Two is underway at two locations: a California Fish and Game lab in Santa Cruz and a wastewater treatment plant in San Francisco. The Santa Cruz lab is our “skunkworks,” where we are experimenting and testing floating PBR and system designs. We have two large seawater tanks and thirty-four 250-gallon tanks in which we are studying biofouling on different types of plastic.