Cleantech
New Algae Process Turns Sewage Into Biofuel and Drinking Water

Nevada-based Algae Systems says it has developed a way to make algae-based biofuel profitable by transforming raw sewage into fuel and clean drinking water.

The company says it has a pilot plant in Alabama that can profitably produces diesel fuel from algae by simultaneously making clean water from municipal sewage, utilizing the carbon-heavy residue as fertilizer and generating valuable credits for advanced biofuels. Using a “hydrothermal liquefaction” system, algae and other solids in the sewage are heated to more than 550 degrees Fahrenheit, at 3,000 pounds per square inch, creating a liquid that resembles crude oil from a well. Scientists then add hydrogen to produce diesel fuel.

Besides producing clean energy and drinking water (which could help with California’s epic drought), the system also could dispose of a variety of unwanted or hazardous materials, and destroy pathogens in sewage. Even better; it removes more carbon from the atmosphere than is added when the fuel is burned.

Entrepreneurs have been looking for a way to making biofuel out of algae for some time, but the process has proved expensive, energy-intensive, and difficult to scale up. Despite the fact that algae is one the fastest-growing organisms on the planet, it still takes too long to accumulate enough usable biomass.

One way to reduce costs is to decrease the amount of time it takes to grow algae. In July, a research team at AlgaStar Inc, a Florida-based algae cultivation company, reported biological simulation yielded a 300 percent increase in algae growth rate over normal conditions. The company's algae production and biostimulation system integrates two types of electromagnetic energy — a millitesla generator and a millimeter microwave generator — which radiate spontaneous growth energy into large volumes of algae biomass to be economically viable.

Recognizing the difficulty of scaling up biofuel production, the U.S. EPA last year backed away from its previously mandated targets for U.S. biofuel production by relaxing the proposed levels of ethanol use outlined in its Renewable Fuel Standard, to address the “E10 blend wall.” The proposal set ethanol use at 15.21 billion gallons — just under 10 percent of motor-fuel consumption and 16 percent lower than targets established by Congress in 2007.

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