Chemical engineers at the University of Arkansas have developed a procedure to produce butanol from algae to be used as a fuel for existing internal combustion engines. Their technology has the additional benefit that the strands of algae used can oxygenate water waste and remove excess nitrogen and phosphorus from fertilizer runoff.
Algae is grown on raceways (long troughs) and the bio-system is provided with nitrogen, phosphorus, carbon dioxide and sunlight in a milieu of creek water. Algae is harvested, dried, ground and the carbohydrate is extracted. This is subjected to a fermentation process to produce butyric acid which is then converted to butanol. Electrodeionization is used to separate butyric acid from undesirable acetic and lactic acids.
Butanol is superior to ethanol with respect to release of energy per unit of mass, it is not corrosive and can be shipped through existing pipelines. Currently a project has been implemented in cooperation with the New York City Department of Environmental Protection to generate biofuel from algae grown at the Rockaway Waste Water Treatment Plant in Queens.