In-Situ Groundwater Nitrification and Denitrification – Bench Scale Testing to Full Scale Remediation

March 22, 2018

RemTech 2018 – October 10, 2018

Steve Mailath, M.Sc., P.Geol.

Principal Hydrogeologist

Table of Contents

01Background

03Bench Scale

Testing

06Summary

04Pilot Scale

Testing

02Site

Information

07Questions

05Full Scale

Remediation

1956 Air

Photo

Background

Geology

Geology

Geology1.5 – 3.0 m Silty Sand

3.7 – 4.5 m Sandy Gravel

silty sand/sandy silt

sandy

gravel

Site Information

Good to excellent drainage

Hydraulic conductivity ~49 m/day

Hydraulic gradient 0.0013 - 0.0026

Groundwater velocity 0.3 - 0.5 m/day

Groundwater flux 144 m3/day (22 igpm)

Ammonia concentration ~50 - 100 mg-N/L

Nitrate concentration ~75 - 100 mg-N/L

Remediation required to prevent discharge of ammonia and nitrate impacted groundwater to Bow River

Solution.

In-situ Groundwater Nitrification1

• Extracting groundwater• Adding oxygen and nutrients• Injection of amended groundwater

In-situ Groundwater Denitrification1

• Extracting groundwater• Adding carbon and nutrients• Injection of amended groundwater

1US and Canadian Patents: Innovate CalgaryDr. Angus Chu, U of C. (Phone: 403.220.8987)Steve Mailath, Trace Associates. (Phone: 403.971.4189)

ReactionsNitrification - conversion of ammonia to nitrate through reactions:

NH4+ + 1.5O2 → NO2

- + 2H+ + H2O

NO2- + ½O2→ NO3

-

As a result, the following overall reaction occurs:

NH4+ + 2O2 → NO3

- + 2H+ + H2O

Denitrification - conversion of nitrate to nitrogen gas through reaction:

2NO3- + 1.5(CH3COOH) → N2 + 3CO2 + 3H2O

(Acetic acid or other carbon source)

Bench Scale Testing

Nitrification Reactor Conditions

Sodium azide killed control (Abiotic

effects)

No nutrient control

Clean soil amended experiment

Nitrified soil amended experiment

No soil control

Activated sludge amended

Denitrification Reactor Conditions

Abiotic effects

Biomass present in soil from the site.

Bonnybrook wastewater treatment plant

activated sludge

Biomass present in the groundwater

Biodegradable substrate (sodium acetate) with

and without the addition of nitrified soil

Bench Test Results

Nitrification: Ammonia Degradation Kinetics

0

20

40

60

80

100

120

140

160

180

0 2 4 6 8 10 12

Time (days)

Am

moni

a C

on

cen

tra

tion

(mg/L

)

Nutrient Addition Sludge No Nutrient Clean Soil No Soil

Bench Test Results

Denitrification: Nitrate Degradation Kinetics

0

20

40

60

80

100

120

140

160

180

200

26-May 29-May 1-Jun 4-Jun 7-Jun 10-Jun 13-Jun 16-Jun 19-Jun 22-Jun 25-Jun

Nit

rate

(m

g/L

)

Acetate Soil Sludge Test Killed Acetate No Soil No Soil Control

1000mg/.L sodium acetate added

2000mg/.L sodium acetate added

1000mg/.L sodium acetate added

In-Situ Nitrification Pilot Scale Testing

In-Situ Denitrification Pilot Scale

Testing

Pilot Test Site

Pilot Test Site

GROUNDWATER FLOW

Pilot Test Site

INJECTION

WELL

EXTRACTION WELL

Pilot Test Site

TREATMENT SHED

Pilot Test Site

TREATMENT SHED

Pilot Test SiteOXYGEN SOURCE

Pilot Test

SiteGAS LIQUID REACTOR

OXYGEN DELIVERY

NUTRIENT DELIVERY

Pilot Test Site

VENTURI

Pilot Test Site

0.00

20.00

40.00

60.00

80.00

100.00

120.00

1 5 9

13

17

21

25

29

33

37

41

45

49

53

57

61

65

69

73

77

81

85

89

93

97

10

1

10

5

10

9

11

3

11

7

12

1

12

5

12

9

13

3

13

7

14

1

14

5

14

9

Days

DO

, A

mm

on

ia,

Nit

rate

- N

Co

nce

ntr

atio

n (

mg

/L)

0.00

0.20

0.40

0.60

0.80

1.00

1.20

Ph

osp

hat

e -

P C

on

cen

trat

ion

(m

g/L

)

TH13 NH4

TH13 NO3

TH13 DO

TH13 PO4

4 per. Mov. Avg. (TH13 NH4)

4 per. Mov. Avg. (TH13 NO3)

4 per. Mov. Avg. (TH13 DO)

Nitrification Results: 66 – 89 % Ammonia Reduction

Pilot Test Site

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

3 4 5 6 7 8 9

10

11

12

13

14

15

16

17

Days

DO

,

Am

mo

nia

, N

itra

te -

N C

on

cen

trat

ion

(m

g/L

)

4 per. Mov. Avg. (TH1 DO)

4 per. Mov. Avg. (TH1 NH4)

4 per. Mov. Avg. (TH1 NO3)

Nitrate

Ammonia

Dissolved

oxygen

Denitrification Results: 78 – 99 % Nitrate Reduction

Full Scale Remediation

Transect 2

Section length - 425 m.

Aquifer thickness – 3 m

Flux - 144 m3/day (22 igpm)

Groundwater

Flow

Full Scale

Remediation

Full Scale

Remediation

Full Scale Remediation

In Line Mixer

Flow Meter

Components

Components

Oxygen Source

Oxygen Generator

VenturiAir Flow Meter

Components

In Line Mixer In Line Mixer

Air Release Valve

Flow Meter

Carbon Source – Pepsi Waste

Carbon Tanks

N8

0

100

200

300

400

500

600

700

Jul-0

9

Aug

-09

Sep-

09

Oct

-09

Nov

-09

Dec

-09

Jan-

10

Feb-

10

Mar

-10

Apr

-10

Time(mm/yy)

Cl m

g/L

0

10

20

30

40

50

60

NH

3-N

& N

O3

-N m

g/L

Cl mg/L

NH3-N mg/L

NO3-N mg/L

N9

0

30

60

90

120

150

180

Jul-0

9

Aug

-09

Sep-

09

Oct

-09

Nov

-09

Dec

-09

Jan-

10

Feb-

10

Mar

-10

Apr

-10

Time(mm/yy)

Cl m

g/L

0

10

20

30

40

50

60

NH

3-N

& N

O3

-N m

g/L

Cl mg/L

NH3-N mg/L

NO3-N mg/L

N12

0

30

60

90

120

150

180

Jul-0

9

Aug

-09

Sep-

09

Oct

-09

Nov

-09

Dec

-09

Jan-

10

Feb-

10

Mar

-10

Apr

-10

Time(mm/yy)

Cl m

g/L

0

10

20

30

40

50

60

NH

3-N

& N

O3

-N m

g/L

Cl mg/L

NH3-N mg/L

NO3-N mg/L

EW4

0

2

4

6

8

10

Jan-

10

Feb-

10

Mar

-10

Ap

r-10

Time

NH

3-N

& N

O3

-N

mg/

L

0

10

20

30

40

50

60

Cl m

g/L

DO mg/LNH3-N mg/LNO3-N mg/L

NITRIFICATION

DENITRIFICATION

0

50

100

150

200

250

300

350

400

0

10

20

30

40

50

60

70

80

Cl m

g/L

NH

3-N

& N

O3

-N m

g/L

Time(mm/yr)

N25NH3-Nmg/L

NO3-Nmg/L

Cl mg/L

In-situ Nitrification and Denitrification Can Be Achieved

Bench Testing Pilot Scale

• Full scale

remediation

reduces

contaminant

discharge to Bow

River

Remediation

39

• Confirmed in-situ

capability• Confirmed

feasibility

Questions

ContactSteve Mailath, M.Sc., P.Geol., smailath@traceassociates.ca