This document summarizes research assessing the performance of natural wetlands in treating domestic wastewater effluents in northern Canada. It finds that wetlands provide treatment benefits and removal of contaminants like BOD, ammonium, phosphorus and pathogens. Predictive tools like SubWet 2.0 were developed to model treatment processes and allow wetlands to be managed as part of a hybrid wastewater treatment strategy along with lagoons. The research addressed gaps in understanding of wetland treatment performance in cold climates and developed sampling protocols and management tools to overcome regulatory challenges and better integrate wetlands into wastewater treatment planning.

1. Assessing the performance of cold climate natural
wetlands in the treatment of domestic wastewater
effluents in northern Canada
Gordon Balch‡, Brent Wootton‡, Colin Yates†, Sven Jørgensen¥ and Annie Chouinard§
‡Centre for Alternative Wastewater Treatment, Fleming College, Lindsay
†Faculty of Environment, University of Waterloo, Waterloo
¥ Water Research Laboratories, ASP, Væløse, Denmark § Civil Engineering Queen’s University, Kingston

2. Focus
• Wetlands are providing a treatment
benefit
• Assessment tools are available
• Wetlands could be part of a
hybridized wastewater treatment
strategy
2

3. Background
• CCME guidelines
• Present and future
challenges for lagoon
systems
• Tundra wetlands exist
downstream of lagoons
3
Pond Inlet – sewage
lagoon
Paulatuk– sewage lagoon

4. Question: do wetlands provide
treatment?
• Anecdotal evidence
• Answer hampered by
– Lack of knowledge
– Lack of standardized
testing
– Inability to predict
response to changing
conditions
4
Ulukhaktu
k

5. Carbon Interactions
DC = dissolved carbon
PC = particulate carbon
DIC = dissolved inorganic carbon
DOC = dissolved organic carbon
Kadlec & Wallace 2008

6. 6
Principal components of the nitrogen cycle in wetlands (Docstoc,
2013)

7. 7
Phosphorus cycling processes: Dissolved inorganic phosphorus (DIP); dissolved
organic phosphorus (DOP); particulate organic phosphorus (POP); particulate
inorganic phosphorus (PIP); inorganic phosphorus (IP) (Reddy, 2008)

8. Question
How well do wetlands perform
in a cold climate?
8

9. Treatment Processes
9
Suspended Solids Phosphorus
sedimentation matrix sorption
filtration plant uptake
Nitrogen Soluble Organics
ammonification aerobic microbial degradation
nitrification anaerobic microbial degradation
denitrification Pathogens
plant uptake sedimentation
matrix absorption filtration
ammionia volatilization natural die-off
Metals predation
adsorption and cation exchange UV irradiation
complexation and precipitation excretion of antibiotics from plant roots
plant uptake
microbial oxidation / reduction
Temperature
Dependent

10. Wetland Surveys 2009-2012
• Phase 1: Arctic Summer
• Phase 2: Rapid Assessment Protocol
• Phase 3: Data Analysis and Tool
development
10

11. Wetland Surveys
i. Arctic Summer (inlet, outlet)
– Seasonal trend
– No pretreatment or pretreatment (facultative
lakes or lagoons)
– Lagoon decants / exfiltration
– Performance (BOD5, TAN, TSS, microbial,
etc.)
– Calibration of SubWet 2.0 rate coefficients for
Northern conditions

12. 12
0
50
100
150
200
250
300
350
Influent Effluent
Arviat, NunavutBOD5mg-L
Sampling Dates

13. 13
0
5
10
15
20
25
30
35
40
45
Influent Effluent
Coral Habour, NunavutTotalAmmoniaNitrogenmg-L
Sampling Dates

14. 14
Wetland Surveys
ii. Intensive Sampling
– Rapid, intensive testing (2-4 days)
– Sampling stations along transects
cBOD5 TKN TAN TSS

15. 15
Wetland Community cBOD5 cBOD5 % m3/d
Size (ha) Infl Effl Red 122 day summer
u.d. Baker Lake 466 6 99 500
17 Gjoa Haven 133 2 98 356
10 Coral Harbour 181 14 92 287
9.5 Repulse Bay 385 25 93 197
7.8 Arviat 130 16 85 703
7.3 Ulukhatok 94 5 95 121
6.1 Taloyoak 80 25 69 257
5.0 Chesterfield Inlet 221 14 94 107
3.7 Whale Cove 40 21 47 245
2.1 Edzo 26 2 92 325
1.5 Paulatuk 40 2 95 102
0.87 Fort Providence 60 32 47
0.58 Pond Inlet 70 50 29 312
• Unusual (large)
• No pre-treatment
• Large vol, size
• Pre-treatment
• Large vol, size
• Pre-treatment
• Good Pre-Treat
• Recalcitrant
• Decant event
• Small wetland
• Small wetland
• Large slope

16. 16
0
10
20
30
40
50
60
70
80
90
100
%FSS %VSS
Sample Location
PercentComposition
Composition of Total Suspended Solids
Pond Inlet
0
20
40
60
80
100
120
140
160
180
Influent Efflluent
TSS

17. 17
0
10
20
30
40
50
60
70
80
90
100
%FSS %VSS
Sample Location
PercentComposition Composition of Total Suspended
Solids Ulukhaktok
0
500
1000
1500
2000
2500
3000
Influent effluent
TSS

18. Predictive Tools
• Rules of thumb (sometimes also called scaling
factors)
• Regression equations and loading charts
• Simple first order kinetic models (e.g., k – C*
model)
• Variable - order, mechanistic or compartmental
models (e.g., SubWet 2.0) and sophisticated 2D
and 3D models (e.g., HYDRUS, WASP, TABS-2,
STELLA) 18

19. Campbell and Ogden 1999
19
As
=
𝑄(ln𝐶𝑜−ln𝐶𝑒
) 𝐾𝑡 ∙𝑑 ∙𝑛
Where:
As = surface area of the wetland
Q = flow, in m3/day
Co = influent BOD (mg/L)
Ce = effluent BOD (mg/L)
Kt = temperature – dependent rate
constant
d = depth of bed medium
n = porosity of bed medium
Kt = K20 θ(T-20)
Where:
K20 = rate constant at 20°C
Θ = theta, the temperature
correction factor set at 1.06
T = temperature of the water in
°C

20. Alberta Model 2000
20
A =
0.0365
𝑄
𝑥 𝑙𝑛
𝐶𝑖−𝐶∗
𝐶 𝑒−𝐶∗
𝑘
Where:
A = area (ha)
k = aerial rate constant @ 20°C, m/yr
Q = design flow (m3/d)
Ci = influent concentration (mg/L)
Ce = effluent concentration (mg/L)
C* = wetland background limit (mg/L)

21. Comparison of 1st Order Kinetic
Model with SubWet 2.0
• Campbell & Ogden predicts that a BOD5
reduction from 205 to 11 mg L-1 can be
accomplished in a wetland 0.25 hectares
in size
• The Chesterfield Inlet wetland can
accomplish this level of treatment BUT
wetland size is 5 hectares
• Campbell & Ogden greatly over estimates
treatment efficiency of wetland
21

22. Predictive tools – SubWet 2.0
22
• 16 rate coefficients
• 25 differential equations
• Easily obtained input parameters
• Ability to calibrate to site conditions
• Models BOD5, Ammonium, Organic
Nitrogen, Nitrate and Total Phosphorus
• Easy to use
• Available as free-ware
• Calibrated to 11 individual tundra treatment wetlands
Nunavut: Arviat, Coral Harbour, Gjoa Haven, Pond Inlet,
Repulse Bay, Whale Cove
NTW: Edzo, Fort Providence, Paulatuk, Taloyoak,
Ulukhaktuk

23. 23
16 Rate Coefficients
Range 0.05-
2.0

24. % Derivation of Simulation from
Measured
24
Nunavut NTW
BOD5 Ammonium Total
Phosphorus
BOD5 Ammonium Total
Phosphorus
Arviat 18 7 2 Edzo 8 15 9
Coral
Harbour 5 14 8
Fort
Providence 79 57 56
Gjoa Haven 2 3 12 Paulatuk 30 10 1
Pond Inlet 5 4 4 Taloyoak 15 2 9
Repusle
Bay 5 4 4 Ulukhaktuk 5 16 11
Whale
Cove 64 10 34
• Provides the lagoon operator the ability to forecast how the wetland will
respond
• Forecast future capacities and needs

25. Calibration of Problematic Sites
for BOD5
25
Before Calibration After Calibration
Community Measured Simulated % Diff Simulated % Diff
Whale Cove 21 8.6 64 21 0.5
Paulatuk 2 13 30 1.9 0.3
Fort Providence 32 9.8 79 34 6.4

26. 26
Summary Report
• 380 pages
• Provides background
to studies
• Overview of wetlands
• Interpretation of the
data
• All raw data
appended
• Predictive tools
• User manual for
SubWet 2.0

27. 27
cawt.ca

28. SubWet published literature
Chouinard, A., Balch, G.B., Wootton, B.C., Jørgensen, S.E. and Anderson, B.C., 2014. Modelling the performance of treatment wetlands in a
cold climate. In Advances in the Ecological Modelling and Ecological Engineering applied on Lakes and Wetlands. 1st Edition. Jørgensen,
S.E.; Chang, N.B.; Fuliu, X., Eds. Elsevier: Amsterdam, Netherlands
Chouinard, A., Yates, C.N., Balch, G.C., Jørgensen, S.E., Wootton, B.C., Anderson, B.C., 2014. Management of Tundra Wastewater Treatment
Wetlands within a Lagoon/Wetland Hybridized Treatment System Using the SubWet 2.0 Wetland Model. Water, 6(3):439-454
Yates, C. N., Wootton, B. C., and Murphy, S. D., 2012. Performance assessment of Arctic tundra municipal wastewater treatment wetlands
through an Arctic summer. Ecological Engineering, 44(0), 160-173
Huang, J.J., Gao, X., Balch, G., Wootton, B., Jørgensen, S.E., Anderson, B. 2014. Modelling of vertical subsurface flow constructed wetlands
for treatment of domestic sewage and stormwater runoff by subwet 2.0. Ecological Engineering 74:8-12.
Huang, J.J., Gao, X., Balch, G., Wootton, B., Jørgensen, S.E., Anderson, B. 2014. submitted. The comparison of first-order model and dynamic
model for the modelling of free water subsurface constructed wetlands: SubWet 2.0 and WASP 7.5.
Jørgensen, S.E.; Gromiec, M.J. Mathematical models in biological waste water treatment—Chapter 7.6. In Fundamentals of Ecological
Modelling, Volume 23, 4th Edition: Applications in Environmental Management and Research; Jørgensen, S.E., Fath, B.D., Eds.; Elsevier:
Amsterdam, the Netherlands, 2011; pp. 1–414.
Yates, C.N., Wootton, B.C., Jørgensen, S.E., Murphy, S.D., 2013. Wastewater Treatment: Wetlands Use in Arctic Regions. In Encyclopedia of
Environmental Management. Taylor and Francis: New York
Yates, C., Balch, G.B., Wootton, B.C., Jørgensen, S.E., 2014. Practical Aspects, Logistical Challenges, and Regulatory Considerations for
Modeling and Managing Treatment Wetlands in the Canadian Arctic. In: Advances in the Ecological Modeling and Ecological Engineering
applied on Lakes and Wetlands. 1st Edition. Jørgensen, S.E., Chang, N. B. and Fuliu, X., Eds. Elsevier, Amsterdam, The Netherlands, 560
pages
Yates, C.N., Balch, G.C., Wootton, B.C., Jørgensen, S.E., 2014. Exploratory Performance Testing of a Pilot Scale HSSF wetland in the
Canadian Arctic. In Advances in the Ecological Modelling and Ecological Engineering applied on Lakes and Wetlands. 1st Edition. Jørgensen,
S.E.; Chang, N.B.; Fuliu, X., Eds. Elsevier: Amsterdam, Netherlands
Yates, C.N., Balch, G.C., Wootton, B.C., Jørgensen, S.E., 2014. Framing the Need for Application of Ecological Engineering in Arctic
Environments. In Advances in the Ecological Modelling and Ecological Engineering applied on Lakes and Wetlands. 1st Edition. Jørgensen,
S.E.; Chang, N.B.; Fuliu, X., Eds. Elsevier: Amsterdam, Netherlands
28

29. 29
Coral Harbour
Northern Wastewater Strategy
Hybridized approach (lagoons + wetlands)

30. Common Challenges
• Cold temperatures lower treatment rates in
lagoons
• Long HRT required
• Accumulation of sludge can decrease
lagoon’s design capacity
• Population growth
• Need to release effluent earlier than
desired
• Treatment targets not achieve
30

31. Wetlands Provide Additional
Treatment
However: Current Regulatory Challenges
• Wetlands considered “receiving
environment”
• Until now, lack of proof in Wetland
performance
• Considered “black box”, no predictive
ability
• No point of control
• How and what should be sampled, where
to analyze (sample shelf life issues) 31

32. 32
• Designate wetlands as part of treatment
train (protect and preserve for future)
• SubWet and interpolated mapping open
the “black box”
• Survey protocols have been developed
and proven to work
Challenges can be overcome

33. SubWet as a Predictive
Management Tool
Scenarios:
• Need to decant early – what volume, conc can be
released before wetland treatment is overwhelmed
• Decant practices (time of year, frequent/small volumes
versus less frequent/larger volumes or exfiltration
versus scheduled decants
• SubWet to predict treatment capacity to meet future
population growth
• Applicable to industrial sites requiring domestic
sewage treatment
• Help regulators better predict treatment capacities of
municipalities
33

34. Concluding Remarks
• Wetlands do provide treatment benefit
• Sampling protocols and predictive tools
exist
• Consideration of a hybridized approach
should be considered
34

35. Concluding Remarks
• Demand for decentralized treatment likely
to increase
• Demand for specialized treatment to off-
load burden to centralized systems may
increase
• May see greater need for advanced
treatment systems for Nitrate and
Phosphorous in relationship to source
water protection
35
Acknowledgements