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PROACTIVE MANAGEMENT OF HAB’s USING IN-LAKE PHOSPHORUS INACTIVATION TECHNOLOGIES
By Dominic Meringolo
Senior Environmental Engineer
Territory Leader
May 13, 2017
Restoring Balance. Enhancing Beauty.
Why Manage Algae?
• Poor water clarity
• Taste & Odor
• Aesthetics
• Recreational impairment
• Diurnal Oxygen Fluctuations
• Cyanobacteria Toxins (HAB’s)
Nuisance Algae Control
Nuisance algae conditions are triggered by excessive nutrients – usually limited by phosphorus
• Control Algae (Treat the symptoms)
– Copper products, alternative algaecides
– Aeration
• Control Nutrients (Treat the source)
– Increase N:P ratio / reduce favorability for cyanos
– Watershed management
– In-Lake Phosphorus Reduction
Why is Watershed Management
Sometimes Not Enough?
• May take many years to make a difference
• Difficult/Expensive to implement
• May not be feasible to lower nutrient concentrations below critical threshold
• Contributions of internal recycling
Methods of In-Lake Phosphorus
Reduction
• Alum Treatment
• Phoslock
• SeClear
• As an alternative to copper treatments until
watershed management efforts come to fruition.
• Address internal recycling when it’s a significant
component of nutrient load.
Alum Treatment - What is
Alum?
• Aluminum Sulfate
• Used extensively in the
drinking water industry.
• Is not a herbicide or
algaecide, but a chemical
precipitant/coagulant that
binds with phosphorus
rendering it biologically
unavailable.
Overview of Alum Technique
• Precipitation vs. Inactivation (Low vs. High Dose)
• Dose Determination (Multiple Methods)
• Dose Verification/Pilot Treatment
• Full-Scale Implementation
• Treatment Monitoring
• Post-Treatment Monitoring
Available Sediment P Reduction (%) vs.
Aluminum Dose (g/m2)
0
10
20
30
40
50
60
70
80
90
100
0 50 100 150 200
Al dose (g/m2)
% R
ed
uc
tio
n i
n a
va
il. P
45 g/m2
74% reduction
Limitations of alum
• Reaction causes drop in pH
• Must be buffered in soft/low-alkalinity water
• Even with buffering, there are still limitations for
smaller and shallow lakes, so only phosphorus-
Precipitation can occur and not phosphorus-
Inactivation of the sediment
• A patented technology which effectively binds and removes free reactive phosphorus (FRP)
• Consists of two naturally occurring components found in soil - Lanthanum embedded inside modified bentonite clay layers
• No significant change in desired water quality parameters during or after application (pH, D.O., Alkalinity, etc.)
What is Phoslock?
1) Immediate Impact
▪ Rapid P binding
▪ As Phoslock moves through the water column it adsorbs P at different depths in the water body
2) Short- term Impact
▪ Reduction in P
▪ As P becomes the limiting nutrient the N:P ratio increases
▪ Resulting in more balanced water quality conditions
3) Longer- term Impact
▪ Phoslock remains active at the bottom of a water body
▪ Adsorbs P released from sediments
▪ Adsorbs P from new inflow water, as settles to bottom
Water Quality Restoration with
Phoslock
• Phoslock slurry injected or surface applied• Tank mix granule with H2O, constant agitation• Even coverage to maximize performance
Phoslock Applications
Example Phosphorous
Management Projects
• Long Pond – Brewster/Harwich, MA (2007)
• Mystic Lake – Barnstable, MA (2010)
• Ticklenaked Pond – Ryegate, VT (2014)
• Cliff Pond – Brewster, MA (2016)
• Crooked Stick Pond (SePRO Demonstration Project)
Long Pond – Brewster/Harwich
• 740-acres
• Largest
waterbody on the
Cape
• State and Town
Funding
• Completed in
2007
• 7 weeks
• 100,000 gallons
combined of alum
and sodium
aluminate
Mystic Lake - Barnstable
• 149-acres
• Treatment of
~50-acres
• 35-50 g/m2
• Mussel
monitoring
• Significant
mussel die-off
prior to treatment
Mystic Lake - Barnstable
• Significant reduction of sediment phosphorus release (>90%)
• Improved water clarity
• No effects on mussels
• Phoslock programs successful throughout US
• rapid phosphorus reduction and improved water quality
• Phoslock continued to bind, resulting in low FRP levels
Application 6/23/11
Questions?
solitudelakemanagement.com • 888.480.LAKE
May 13, 2017
By Dominic Meringolo
Senior Environmental Engineer
Territory Leader