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

Focus

• Wetlands are providing a treatment

benefit

• Assessment tools are available

• Wetlands could be part of a hybridized

wastewater treatment strategy

2

Background

• CCME guidelines

• Present and future challenges

for lagoon systems

• Tundra wetlands exist

downstream of lagoons

3

Pond Inlet – sewage lagoon

Paulatuk– sewage lagoon

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

Ulukhaktuk

Carbon Interactions

DC = dissolved carbon

PC = particulate carbon

DIC = dissolved inorganic carbon

DOC = dissolved organic carbon Kadlec & Wallace 2008

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

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)

Question

How well do wetland perform in a

cold climate?

8

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

Wetland Surveys 2009-2012

• Phase 1: Arctic Summer

• Phase 2: Rapid Assessment Protocol

• Phase 3: Data Analysis and Tool development

10

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

11

12

0

50

100

150

200

250

300

350

Influent Effluent

Arviat, Nunavut B

OD

5 m

g -

L

Sampling Dates

13

0

5

10

15

20

25

30

35

40

45

Influent Effluent

Coral Habour, Nunavut T

ota

l A

mm

on

ia N

itro

gen

mg -

L

Sampling Dates

14

Wetland Surveys

ii. Intensive Sampling

– Rapid, intensive testing (2-4 days)

– Sampling stations along transects

cBOD5 TKN TAN TSS

Ulukhaktok

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

0

10

20

30

40

50

60

70

80

90

100

%FSS %VSS

Sample Location

Perc

en

t C

om

po

siti

on

Composition of Total Suspended Solids

Pond Inlet

0

20

40

60

80

100

120

140

160

180

Influent Efflluent

TSS

17

0

10

20

30

40

50

60

70

80

90

100%FSS %VSS

Sample Location

Perc

en

t C

om

po

siti

on

Composition of Total Suspended Solids

Ulukhaktok

0

500

1000

1500

2000

2500

3000

Influent effluent

TSS

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

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

Alberta Model 2000

20

A = 0.0365𝑄

𝑥𝑙𝑛 𝐶𝑖−𝐶

∗

𝐶𝑒−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)

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

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

16 Rate Coefficients

Range 0.05-2.0

% 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

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

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

cawt.ca

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

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29

Coral Harbour

Northern Wastewater Strategy

Hybridized approach (lagoons + wetlands)

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

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)

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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

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

Concluding Remarks

• Wetlands do provide treatment benefit

• Sampling protocols and predictive tools exist

• Consideration of a hybridized approach should

be considered

34

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