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

Alberta Onsite Wastewater Management Association: 2015 Conference and Trade ShowSaturday, March 7th, 2015, Edmonton, Alberta

2

Focus• Wetlands are providing a

treatment benefit• Assessment tools are available• Wetlands could be part of a

hybridized wastewater treatment strategy

3

Background

• CCME guidelines• Present and future

challenges for lagoon systems

• Tundra wetlands exist downstream of lagoons

Pond Inlet – sewage lagoon

Paulatuk– sewage lagoon

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Question: do wetlands provide treatment?

• Anecdotal evidence• Answer hampered by– Lack of knowledge – Lack of standardized

testing– Inability to predict

response to changing conditions Ulukhakt

uk

Carbon Interactions

DC = dissolved carbonPC = particulate carbonDIC = dissolved inorganic carbonDOC = dissolved organic carbon

Kadlec & Wallace 2008

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

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

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Question

How well do wetlands perform in a cold climate?

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Treatment ProcessesSuspended 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 precipitationexcretion of antibiotics from plant roots

plant uptakemicrobial oxidation / reduction

Temperature Dependent

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Wetland Surveys 2009-2012

• Phase 1: Arctic Summer

• Phase 2: Rapid Assessment Protocol

• Phase 3: Data Analysis and Tool development

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

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0

50

100

150

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Influent

Arviat, NunavutB O D 5 m g

-

L

Sampling Dates

0

5

10

15

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40

45

InfluentEffluent

Coral Habour, NunavutTo ta

l A m m on ia

Ni tr og en

m g -

L

Sampling Dates

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Wetland Surveys

ii. Intensive Sampling– Rapid, intensive testing (2-4 days)– Sampling stations along transects

cBOD5 TKN TAN TSS

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Wetland Community cBOD5 cBOD5 % m3/d

Size (ha) Infl Effl Red122 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

Influ

ent

PI9

PI8

PI7

PI6

PI5

PI4

PI3

PI2

PI1

0

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%FSS %VSS

Sample Location

Per

cen

t C

omp

osit

ion

Composition of Total Suspended SolidsPond Inlet

Influent Efflluent0

20

40

60

80

100

120

140

160

180

TSS

Influ

ent a

Influ

ent b

T1S2

T7S3

T8S1

T8S4

T10S

1

T10S

2

T10S

4

T11S

10

10

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100%FSS %VSS

Sample Location

Per

cen

t C

omp

osit

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Composition of Total Suspended Solids Ulukhaktok

Influent effluent0

500

1000

1500

2000

2500

3000

TSS

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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)

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Campbell and Ogden 1999

As =

𝑄(ln −ln𝐶𝑜)𝐶𝑒 ∙ 𝐾𝑡 𝑑

∙ 𝑛Where: 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

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Alberta Model 2000

A =0.0365𝑄 𝑥𝑙𝑛 𝐶𝑖−𝐶∗𝐶𝑒−𝐶∗

𝑘Where:

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)

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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

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Predictive tools – SubWet 2.0

• 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 CoveNTW: Edzo, Fort Providence, Paulatuk, Taloyoak, Ulukhaktuk

16 Rate Coefficients

Range 0.05-2.0

% Derivation of Simulation from Measured

Nunavut NTWBOD5 Ammonium Total

PhosphorusBOD5 Ammonium Total

Phosphorus

Arviat 18 7 2 Edzo 8 15 9Coral 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 9Repusle Bay 5 4 4 Ulukhaktuk 5 16 11Whale Cove 64 10 34

• Provides the lagoon operator the ability to forecast how the wetland will respond

• Forecast future capacities and needs

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Calibration of Problematic Sites for BOD5

Before Calibration After Calibration

CommunityMeasure

dSimulate

d % DiffSimulat

ed % 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

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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

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cawt.ca

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SubWet published literatureChouinard, 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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Coral Harbour

Northern Wastewater Strategy

Hybridized approach (lagoons + wetlands)

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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

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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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• 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

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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

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Concluding Remarks

• Wetlands do provide treatment benefit

• Sampling protocols and predictive tools exist

• Consideration of a hybridized approach should be considered

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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

Acknowledgements