The document discusses harmful algal blooms (HABs), which are primarily caused by nutrient pollution, especially from stormwater runoff, and highlights their significant impacts on human health, environment, and economy. Multiple methods for preventing and controlling HABs are outlined, including physical, chemical, biological, and direct nutrient removal strategies, each with their own advantages and drawbacks. Additionally, the use of fluorometers for real-time detection of blue-green algae is mentioned as a practical solution for timely intervention.

1. Can We Eliminate Algal Bloom?
Project Presentation by Team 6A
Jan. 16, 2018

2. Harmful Algal Blooms
Harmful Algal Blooms (HABs) are a type of algae
that grows quickly and forms blooms, where the
algae grows to cover most or all of the lake or
pond, often resulting in a colored scum on the
surface.
HABs are most prevalent in nutrient rich waters
when the weather is hot and calm.

3. Algal bloom happens because excess nutrients are in waters. Sunlight, slow-moving
water, and higher levels of nutrients like nitrogen (which is used to make fertilizers)
and phosphorus (which is used in detergents) cause extreme growth of algae and
aquatic plants.
Stormwater runoff is one of the largest single contributors of this nutrient pollution
to our water systems. Water that travels along solid surfaces pick up pollutants
such as fertilizers, pesticides and feces and carry them into streams, rivers, ponds,
lakes and wetlands.
What Causes Algal Bloom?

4. Impact of Algal bloom: Human Health
● Direct exposure to toxic algae. Drinking, accidentally swallowing or
swimming in water affected by a harmful algal bloom can cause serious
health problems including:
○ Rashes
○ Stomach or liver Illness
○ Respiratory Problems
○ Neurological Effects
○ Algae blooms produce toxins harmful to humans and marine life.
● Byproducts of water treatment. When disinfectants used to treat drinking
water react with toxic algae, harmful chemicals called dioxins can be
created. These byproducts have been linked to reproductive and
developmental health risks and even cancer.

5. Impact of Algal bloom: Environmental
● Harmful algal blooms sometimes create toxins that can kill fish and other animals.
After being consumed by small fish and shellfish, these toxins move up the food
chain and hurt larger animals like sea lions, turtles, dolphins, birds, manatees, and
fish.
● Even if algal blooms are not toxic, they can hurt aquatic life by blocking out
sunlight and clogging fish gills.
● Nutrient pollution can create dead zones, areas in water with little or no oxygen
where aquatic life cannot survive.
○ Over 166 dead zones have been documented nationwide, affecting water
bodies like the Chesapeake Bay and the Gulf of Mexico. The Gulf of Mexico
dead zone is the largest in the United States, measured to be 5,840 square
miles in 2013.

6. Impact of Algal bloom: Economy
● Drinking water costs. Nitrates and algal blooms in drinking water sources
can drastically increase treatment costs. Nitrate-removal systems in
Minnesota caused supply costs to rise from 5-10 cents per 1000 gallons to
over $4 per 1000 gallons. It can also cost billions of dollars to clean up
polluted water bodies.
● Tourism losses. The tourism industry loses close to $1 billion each year,
mostly through losses in fishing and boating activities.
● Commercial fishing and shellfish losses. Annual losses to these industries
from nutrient pollution are estimated to be in the tens of millions of dollars.
● Real estate losses. Clean water can raise the value of a nearby home by up
to 25 percent.

7. Ways to prevent/control HABs
Many different ways have been discovered to both prevent Harmful Algal Blooms
and stop them once they already occur.
These ways have been divided into four categories depending on the way they
stop the HABs:
● physical controls
● chemical controls
● biological controls
● direct nutrient removal

8. Physical Controls
Using physical methods to remove algae from the water.
This method includes:
● Aeration
● Mechanical mixing
● Surface skimming
● Ultrasound

9. Aeration
Air is pumped into a pond or lake from an aeration device placed on the
bottom.
This forms plumes of air that disrupt the stratification of the body of water
and limit the nutrients the algae can get.
Drawback - Proximity limit of mechanical devices

10. Mechanical Mixing
Mixers are placed on the surface of the body of water and either pump water
from the surface downwards or draw water from the bottom up.
This mixes the water, disrupting the stratification and limiting nutrients to the
algae.
Drawback - Proximity limit of mechanical devices

11. Surface Skimming
Algae blooms often form surface scums.
By using oil skimmers, the algae can be removed.
Drawback - High labor cost

12. Ultrasound
Ultrasonic waves of a particular frequency are used to kill the algae by
destroying their cellular structure.
Drawback - Transmitter could be blocked; Need reprogramming for different types of algae

13. Chemical Controls
Using chemical methods to remove algae from the water.
Chemical controls include:
● Algaecides
● Barley straw
● Coagulation

14. Algaecides
Chemical compounds that kill algae.
These compounds include:
● Copper sulfate, copper citrate, and other copper based products
● Potassium permanganate
● Chlorine
● Lead
Drawback - Harmful to the environment

15. Barley Straw
Bales of barley straw are placed in the water.
When exposed to sunlight and oxygen, the straw produces a chemical that
stops algae growth.
Drawback - Cannot produce chemical without sunlight; Occupy space

16. Coagulation
Chemicals are introduced into the water that makes the algae coagulate and
fall to the bottom of the pond or lake.
At the bottom, the algae has no access to light, oxygen, or other critical
resources, eventually dies.
Drawback - Current ways of applying the solution are not efficient and effective

17. Appendix: Triple Strike (Coagulation)
TRIPLE STRIKE is a revolutionary, one step treatment for algal blooms in farm
and other water bodies:
● The alum consolidates the algae into fluffy “lumps”
● The inert mineral attaches to the lumps of algae, causing them to fall
rapidly through the water
● The gypsum forms a blanket over the algae on the floor of the water body
and also absorbs toxic and phosphorus from the water, inhibiting new
algal growth.
● 50-150 mili-liter/square meter

18. Biological Controls
Using biological processes to remove algae from water.
Biological controls include:
● Floating Artificial Wetlands
● Increasing grazing pressure

19. Floating Artificial Wetlands
Plants are placed on floating mats and placed in the
water.
As the plants grow, they filter excess nutrients from
the water, helping to prevent an algae bloom.
When the plants mature, they need to be switched
out with young plants in order for the process to
continue.
Drawback - Occupy space; Need effort for planting and switching to young plants

20. Increasing Grazing Pressure
By increasing the growth of zooplankton, plants, and other organisms that feed on algae,
it will be less likely for algae to experience a bloom.
This can be done by removing fish that feed on these organisms.
Drawback - May introduce new risks

21. Direct Nutrient Removal
When the food that the algae feeds on is taken away in order to control the
algae growth, it is called direct nutrient removal.
There are two main products that do this:
● Alum
● Phoslock
Both of these products remove phosphorus from the water.
Drawback - Current ways of applying the solution are not efficient and effective

22. References
http://www.waterrf.org/knowledge/source-water-protection-and-
management/FactSheets/SourceWater_FactSheet_algae.pdf
https://www.epa.gov/nutrientpollution/effects
http://making-biodiesel-books.com/about-algae/algae-bioreactors/
http://dnr.wi.gov/lakes/bluegreenalgae/
https://www.pitchcare.com/shop/aquatic-algae-control/triple-strike-revolutionary-algae-control.html
https://link.springer.com/chapter/10.1007/978-94-007-5479-9_16
https://www.aquaread.com/need-help/what-are-you-measuring/blue-green-algae/
http://www.green-flow.co.il/Documents/TRIPLESTRIKE/Triple%20Strike%20Flyer.pdf

23. Appendix: Sensor for detecting algae
● Conducting a blue green algae test using fluorometers is possible because the pigments within the
bacteria are fluorescent. This means that when light of a certain wavelength is emitted, the algae
absorbs the light energy and emits a light of their own. A fluorometer is a form of blue green algae
sensor that enables concentrations of it to be tested in the field, which means that it’s not
necessary to collect samples for analysis in a laboratory. Laboratory analysis can be a lengthy
process and delay control actions. Using a fluorometer to detect it provides instant results.
(https://www.aquaread.com/need-help/what-are-you-measuring/blue-green-algae/
● A fluorometer or fluorimeter is a device used to measure parameters of fluorescence: its
intensity and wavelength distribution of emission spectrum after excitation by a certain
spectrum of light. These parameters are used to identify the presence and the amount of
specific molecules in a medium.