http://www.rdmag.com/news/2015/03/algae-clogged-waterways-could-serve-biofuels-fertilizer
Algae from clogged waterways could serve as biofuels, fertilizer
Wed, 03/25/2015 - 11:31am
by American Chemical Society
Water-borne algal blooms from farm fertilizer runoff can destroy aquatic
life and clog rivers and lakes, but scientists will report today that
they are working on a way to clean up these environmental scourges and
turn them into useful products. The algae could serve as a feedstock for
biofuels, and the feedstock leftovers could be recycled back into farm
soil nutrients.
A multi-pronged nutrient bio-remediation system is the goal of a team of
scientists.
"I grew up on a farm, and I know firsthand the needs of small-scale
farmers, as well as the problems posed by algal blooms," says John B.
Miller, PhD. "But I am also a chemist, so I see an upside with algae."
Algae can range in size from a single cell to large seaweeds. They only
need water, sunlight and a source of nutrients to grow. But 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
clumps called algal blooms that can be directly toxic to fish and other
aquatic life. The blooms also can draw oxygen from the water, creating
dead zones, where most life cannot exist.
But Miller and his team at Western Michigan Univ. envision 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 are getting underway and are growing natural
communities of periphytic or attached algae for biofuel production.
Miller is building on this approach but will downsize it to water bodies
near small farms throughout the U.S.
"For small farm applications, the system must be easy to operate, nearly
automatic and be suitable for diffuse installations," he says. "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 water bodies. 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 out in the field. Also, they are
investigating different options for collection techniques that will be
more appropriate for small, remote locations.
Miller points out that the algae can be used for biofuel feedstock,
making a profit for the farmers. And 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 up and running at farms, but
Miller says 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 says.
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