Page 16 - Port of Baltimore Magazine - July/August 2013
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The Port of Baltimore
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July/August 2013
GREENPORT
I
n the late 1970s and early 1980s,
Dr. Walter Adey of the Smithsonian
Institution was studying coral reefs
and noticed that algae, helped by wave
action, grew well on the tips of coral.
He found he could create a controlled
algae environment on land, and then
send water through it to strip excessive
nutrients.
A similar bio-mimicry system has
recently been installed at the Port of
Baltimore’s Dundalk Marine Terminal as
an experiment to help remove the harmful
nutrients that cause the algae blooms
in the Chesapeake Bay. Essentially,
scientists are creating a controlled algae
bloom — but one that attaches to a
screen so that they can easily remove the
algae and its load of nutrients.
“We create conditions for algae to
grow and harvest it regularly, which pulls
nutrients out of the water column,” said
Dr. Peter May, a Senior Environmental
Scientist with Biohabitats Inc. and an
adjunct professor at the University of
Maryland. “The technology has been
studied quite a bit. The Port has this need
of reducing nutrient load and this is one
of the most effective ways of doing it.”
Once removed, the algae is dried
and has been experimentally turned
into biofuel, such as ethanol, butanol
or biodiesel. Algae also can be used to
demonstrate the production of other
products, such as dietary supplements,
soil amendments, animal feed and
compost. But the primary goal of the
system is to clean the water; harvested
algae byproduct reuse is a secondary
benefit.
The Maryland Port Administration
(MPA) reviews all available technology to
improve water quality and comply with
the Total Maximum Daily Load (TMDL),
which is the amount of pollutants a body
of water can receive and still maintain
water quality.
Jamie Smith, an Environmental
Specialist with the Maryland
Environmental Service, explained that
at the Dundalk terminal, the water is
pumped out of the harbor at a rate of
90 gallons per minute. It flows across
the scrubber, a plastic sheeting material
with a screen that is 300 feet long and
six feet wide, and then is returned to the
harbor. As the water runs through the
scrubber, the algae grows, feasting on the
nutrients and carbon in the harbor water
to create biomass while injecting oxygen
back into the water as a byproduct of
photosynthesis. Once a week, the algae
will be removed from the scrubber by
scraping or vacuuming. Then, scientists
will analyze it, taking both wet and dry
measurements, to see how much nitrogen,
phosphorus and carbon are removed in
each pound of algae and determine how
much oxygen is resupplied to the harbor.
“We’re using it to meet our Total
Maximum Daily Load goals for our
Maryland Department of the Environment
permit,” Smith said. The scrubber, which
was in use on the Eastern Shore on an
agricultural field, has been reconstructed
at the terminal.
MPA Installs Experimental
Algae Scrubber
BILL MCALLEN
BILL MCALLEN
