Will Florida sun light solve the Caloosahatchee River nitrogen problem?

Anura Karuna-Muni, P.E. Tom Emenhiser

Richard Lewis, PhD, PE

Lee County TMDL Obligations: Caloosahatchee River – 140,853 pounds of TN per year Everglades West Coast Basin - 10,084 pounds of TN per year Imperial River – 1,556 pounds of TN per year

What we have done so far to accomplish these goals: Monitoring of Water Quality Construction of Filter Marshes Source Control Land Acquisition for consservation Experimenting New Technologies

UV Technology in Water Treatment Waste Water Storm Water

UV Sources Artificial UV sources Sunlight

Lee County Initiative to experiment with UV Technology in Storm Water Treatment Bench Scale Testing Proposed Full Scale Pilot Testing

Testing Locations Lakes Park (LP) – Phase I Caloosahatchee River (CR) – Phase II Nalle Grade Stormwater Park (NGSP)

LP

CR NGSP

Nalle Grade Stormwater Park

Project Goals & Layout

Goals of the project: Measure UV radiation from sunlight Measure water quality Measure flow rates Develop relationships between UV radiation, reduction in water quality and flow rates Evaluate efficiency of UV treatment in storm water

Nitrogen

• Ammonia:

• Nitrate:

• Nitrogen gas:

Organic Nitrogen

• Simple: • Amines • Amides • Nitroso

• Complex: • Humic / Fulvic Acids • Nylon

WWTP Process

Process

• Break organic nitrogen-containing molecules into smaller, more biodegradable pieces (direct uv on molecule, photo-oxidation, etc).

Caloosahatchee River

Source water average nitrogen concentrations (mg/L as N)

Total Ammonia Nitrate+Nitrite Organic Nitrogen Total Nitrogen (mg/L as N)

0.04 0.37 1.1 1.5

% 2 25 73 --

Caloosahatchee TMDL requires 23 percent reduction for Total Nitrogen

Phase I UV Pilot Study Location

Pilot Study Location

Phase I Pilot Study Configuration

Sample 1

Sample 2

Sample 3

Sample 4

Phase II Pilot Unit Location Map

Phase II Pilot Unit Trailer Showing

Intake Line and Feed Pump

View of Intake Line in the

Caloosahatchee River

Phase II Pilot Unit Tanks, Columns

and UV Lamp

Schematics of Phase II Bench Testing

Components at Caloosahatchee River

19

FY18-19 -- Re-Skin Sprung Units at Ortiz Jail -- $2 million

Ammonia

(NH3/NH4+

)

NO2-

Organic Nitrogen

NO3-

N2 Gas

+ O2 (Nitrosomonas)

+ O2 (Nitrobacter)

Anoxic

UV radiation

Organic Nitrogen

Ammonia

NO2-

NO3-

N2 Gas

Plant uptake

UV radiation

OR

Organic Nitrogen Conversion Process

Amount of Ammonia Released After UV

Feed at Varied Flow Rates

Table 6 Average Dissolved Organic Nitrogen (DON) and Total Dissolved Nitrogen (TDN)

for Various Sampling Points Sampling Points DON NOx (NO3 and NO2) NH4 TDN

Feed 1.015 0.368 0.039 1.42

Post UV 1.006 0.354 0.054 1.41

T1 1.024 0.34 0.070 1.43

T2 0.994 0.092 0.025 1.11

C1 1.041 0.361 0.033 1.44

C2 1.050 0.194 0.019 1.26

• The UV Lamp increased the ammonia concentration from 39 ppb to 70 ppb (an 80% increase in ammonia) in post column 1 samples (60 ml/min flow rate or 40 minute HRT).

• Nitrate+nitrites were much lower in the T2 column (92 ppb) than the C2 control column (194 ppb) suggesting denitrification to low levels may be limited by bio-available carbon in the natural system.

Significant Phase II Study Results

• The abiotic technique of exposing surface waters to concentrated UV light can cleave ammonia from DON.

• The UV source used for this pilot work was a Trojan low pressure monocrhromatic UV wavelength of 254 angstroms lamp.

• In order to achieve 23 percent reduction in Total Nitrogen in the Caloosahatchee River it is felt a combination of biotic and abiotic treatment techniques will be required.

• Plant based filter marshes (emergent, SAV, Periphyton Mats, etc.) will remove some particulate and inorganic nitrogen forms however, the refractory 1 mg/L of DON will be problematic for these techniques.

Conclusions and Recommendations

• Elements of the experimental design would include:

− Testing of a new UV source – medium pressure broad wavelength (200 to 400 angstrom) which would provide a more intense dosage;

− Fresnel lenses would be evaluated as a means of passive concentration of sunlight at different wavelengths and shallow (8 to 10 inches in depth) sheet flow cells would be coupled with deeper SAV cells.

− Bio filters would assess the denitrification potential with and without supplemental bio available carbon sources.

Conclusions and Recommendations

Questions?