Algae from clogged waterways could serve as biofuels, fertilizer, research finds

A team of scientists from Western Michigan University reported that they are working on a way to clean up waterborne algal blooms from farm fertilizer runoff that can destroy aquatic life and clog rivers and lakes and turn them into useful products.

Mar 25th, 2015

DENVER, CO, March 25, 2015 -- Today at the 249th National Meeting & Exposition of the American Chemical Society (ACS) -- the world's largest scientific society -- a team of scientists from Western Michigan University (WMU), located in the city of Kalamazoo, Mich., reported that they are working on a way to clean up waterborne algal blooms from farm fertilizer runoff that can destroy aquatic life and clog rivers and lakes and turn them into useful products.

Ultimately, the goal of the WMU scientists is a multi-pronged nutrient bioremediation system that can transform algae to serve as a feedstock for biofuels, where the feedstock leftovers could be recycled back into farm soil nutrients.

Algae can range in size from a single cell to large seaweeds and only need water, sunlight and a source of nutrients to grow. However, with a boost from high levels of man-made nutrients -- particularly nitrogen and phosphorus from farm runoff -- the growth springs out of control. They form algal blooms that can be directly toxic to fish and other aquatic life and can also draw oxygen from the water, creating dead zones, where most life cannot exist.

The WMU team envisions a solution to problematic algal blooms, which can benefit small-scale farmers. Already, algae are gradually but increasingly being used as a feedstock for different classes of biofuels, including ethanol. It grows very quickly -- some two to eight times faster than similar land-based ethanol feedstocks, such as corn, soybeans or cellulosic biomass -- which is an advantage.

Large-scale, centralized "algal turf scrubber" operations in Florida and elsewhere, for example, are already underway and are growing natural communities of periphytic, or attached algae, for biofuel production. Miller is building on this approach but will restrict it to waterbodies near small farms throughout the United States.

"For small farm applications, the system must be easy to operate, nearly automatic and be suitable for diffuse installations," said John B. Miller, Ph.D. "So, my focus has been to apply this technology without requiring the large infrastructure of the electric grid, large pumping installations and all the rest that is needed for centralized operations. A farmer won't have time to check an algae collection and processing system, so it has to also be able to operate remotely."

Currently, the team is exploring different substrates to optimize algae growth in waterbodies. By using 3-D printing technologies, the researchers engineer substrates to provide different geometric features that foster growth of algal blooms. They are testing these first in the laboratory before analyzing them in the field. Further, they are investigating different options for collection techniques that will be more appropriate for small, remote locations.

Miller noted that the algae can be used for biofuel feedstock, making a profit for the farmers. Likewise, the waste left over after the biofuel's fermentation and distillation steps is high in nutrients and carbohydrates, which is a material that can be recycled back to farm fields for use as an organic fertilizer.

It may take a while to get the system operating at farms, but Miller said that there is a powerful economic incentive for farmers to sign on. That's because it has the potential to shift problematic algae into biofuels, taking a farm-based ecological problem and turning it into a revenue stream for small-scale farmers, he said.

See also:

"New partnership paves way for advanced use, treatment of biosolids as a fertilizer"

"Nutrient Recovery Technology Transforms World's Largest Wastewater Treatment Plant"

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