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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
