© 2014 HDR ©
©
Architecture,
2014
2014 HDR,
HDR,Inc.,
Inc.,
Inc.,all
all
allrights
rights
rightsreserved.
reserved.
reserved.
COMPARISON OF MBBR
AND SUSPENDED GROWTH
BNR PERFORMANCE AT
THE HRWTF
Erika L. Bailey, PE
NC AWWA WEA Annual Conference
November 16, 2015
© 2014 HDR, Inc., all rights reserved.
01
02
03
04
05
Introduction, Drivers, and
Challenges
Segregated Treatment
Concept
MBBR / Suspended Growth
Comparison
Conclusions
Project Status
01
INTRODUCTION,
PROJECT DRIVERS,
AND CHALLENGES
HRWTF IS A PUBLICLY
OWNED INDUSTRIAL
TREATMENT WORKS
Located 20 miles southeast of
Richmond, VA
50 mgd capacity, currently treating
28 mgd
Small domestic base flow
•
•
•
•
23,000 residents
LARGE industrial contribution
•
•
85% of flow
High Purity Oxygen (HPO)
activated sludge with denitrification
•
•
No nitrification currently
HRWTF EXISTING LIQUID TREATMENT PROCESS
“HAP” Foul Condensate
VAWCO
RockTenn
Hercules
Gravelly Run
Industrial
Headworks
Reaeration
Industrial
Primary
Clarifiers
Evonik
Honeywell
Denit.
Basin HPO Aeration Tanks
RAS
Final
Clarifiers
HOCl
Domestic
Domestic
Headworks
Domestic
Primary
Clarifiers &
Chlorine Contact
Tanks
2012
Improvements
(Phase 1)
PROJECT DRIVERS
Nitrogen (TN) Reduction
•
•
•
•
Chesapeake Bay Nutrient TMDL
HRWTF currently purchases TN credits
Future market for credit purchases
unknown
Ammonia (NH3-N) Reduction
•
•
•
Current NH3-N limit: 18.9 mg/L
30% - 90% reduction anticipated
• Monthly Avg: 2.0 – 14.2 mg/L
• Daily max: 3.1 – 21.6 mg/L
Total Nutrient Discharge
Load by Year (Mlb/yr)
HRWTF Waste
Load Allocation
2005
2006
2007
2008
2009
2010
2011
TP
TN
0.075
1.83
ND
ND
ND
0.048
0.013
0.028
0.020
1.9
1.55
1.7
1.57
1.88
2.02
1.77
NITROGEN REMOVAL IS
CHALLENGE AT HRWTF
High influent
temperatures
exceed 37 ºC
• Exceeds upper temperature limit
for stable nitrification
creates air permitting
High concentration • Cooling
challenges
of VOCs
Variable influent
wastewater
characteristics
• Impacts process performance
stability
nitrification rates
Wastewater contains • Slower
expected (larger aeration tanks)
nitrification inhibitors
02
ADDRESSING BNR
CHALLENGES:
SEGREGATED
TREATMENT CONCEPT
PROJECT DEVELOPMENT APPROACH
Effectively build upon previous studies
•
•
“Segregated Treatment” alternatives to address key challenges
Leverage knowledge from previous testing
•
•
Effectively address nitrification inhibition
2007 Comprehensive
Alternatives Evaluation
identified Segregated
Treatment as preferred
alternative
UNIQUE “SEGREGATED TREATMENT” APPROACH
ADDRESSES TEMPERATURE CHALLENGE
Separate high nitrogen and high temperature streams
Achieves biological nutrient removal on portion of flow
•
•
•
Eliminates need for cooling industrial influent
BUT
•
•
Honeywell wastewater contains nitrification inhibitors
Domestic
Honeywell
Total
Influent
Ashland
RockTenn
VAWCO Evonik
Honeywell
Primary
Treatment
Primary
Treatment
Biological
Nutrient
Removal
Segregated
Stream
Combined
Influent
Secondary
Treatment
Final
Effluent
SEGREGATED TREATMENT APPROACH MUST
ALSO ADDRESS NITRIFICATION INHIBITION
•
•
Limit Honeywell flow to Segregated Treatment
Use MBBR system for biological treatment
•
•
•
•
•
High rate process
Concentrated biomass; media provides high surface area to volume environment
Biofilm structure
Media contained within separate cells
Self-regulating system (do not manage SRT)
MBBR: Moving Bed Biofilm Reactor
Anoxic Cell
BOD Removal Cell
Nitrification Cells
PILOT TESTING CONDUCTED TO CONFIRM
DESIGN BASIS
Side-by-side comparison of suspended growth and MBBR processes
Both processes fed with the same influent flow stream
•
•
•
•
Domestic primary effluent
Gradually increased levels of Honeywell flow
03
COMPARISON OF MBBR /
SUSPENDED GROWTH
PERFORMANCE
PILOT TESTING CONFIGURATION
PILOT TESTING CONDITIONS
Scenario
Description
1
2
3
40% HW @ Design Avg
70% HW @ Design Avg
100% HW @ Design Avg
Influent %
Honeywell
19%
29%
37%
95.0%
90.0%
SG
85.0%
MBBR
80.0%
75.0%
70.0%
3/17
3/24
3/31
4/7
4/14
4/21
TN Removal
SG
MBBR
MBBR Recycle
100.0%
200%
80.0%
160%
60.0%
120%
40.0%
80%
20.0%
40%
0.0%
0%
3/17
3/24
3/31
4/7
4/14
4/21
MBBR Internal Recycle (%)
•
TN removal in MBBR dropped
when internal recycle was
temporarily stopped.
TN removal quickly increased
to the same levels as the
Suspended Growth system
once the recycle stream
resumed.
NH3-N Removal (%)
•
100.0%
TN Removal (%)
SCENARIO 1 –
40% HONEYWELL
Ammonia-N Removal
Ammonia reduction
•
•
Both systems achieved <1.0 mg/L
NH3 for 85% of the time.
Effluent Ammonia-N (mg/L)
SCENARIO 1 –
40% HONEYWELL
•
MBBR DAF unit provided greater
and more consistent solids removal.
Polymer was not needed.
40%
60%
1.0
0.1
0.0
0%
20%
80%
100%
Percent Values Less Than or Equal to Indicated Value
Suspended Growth
MBBR
100.0
Effluent TSS (mg/L)
•
MBBR
10.0
Solids removal
•
Suspended Growth
10.0
1.0
0%
20%
40%
60%
80%
Percent Values Less Than or Equal to Indicated Value
100%
MBBR
•
•
More stable removal of ammonia
and TN
100.0%
NH3-N Removal (%)
SCENARIO 2 –
70% HONEYWELL
Ammonia-N Removal
95.0%
MBBR
85.0%
80.0%
Suspended Growth
•
4/21
4/28
5/5
5/12
5/19
5/26
TN Removal
Drop in nitrification performance due
to an unexplained loss of biomass
90.0%
80.0%
70.0%
TN Removal (%)
•
SG
90.0%
60.0%
50.0%
SG
40.0%
MBBR
30.0%
20.0%
10.0%
0.0%
4/21
4/28
5/5
5/12
5/19
5/26
•
Decrease in SRT and MLSS
SRT may have reached as low as 9 days
(7 day aerobic SRT).
Nitrifier washout not expected (at 18 °C)
•
•
But continuous nitrification inhibition
experienced in the Suspended Growth
system would make it more sensitive to the
low SRT impacts.
5,000
80
4,000
60
3,000
40
2,000
20
1,000
0
0
4/21
4/28
5/5
Eff. TSS
TSS (mg/L)
•
100
5/12
5/19
5/26
Total SRT
100.0
50
90.0
45
80.0
40
70.0
35
60.0
30
50.0
25
40.0
20
30.0
15
20.0
10
10.0
5
0.0
0
4/21
4/28
5/5
5/12
5/19
5/26
SRT (days)
Sudden increase in effluent TSS from the
Suspended Growth system
•
TSS (mg/L)
SCENARIO 2 –
70% HONEYWELL
MLSS
MLSS (mg/L)
Eff. TSS
•
•
Suspended Growth system
achieved <1.0 mg/L NH3 about 70%
of the time.
MBBR achieved <1.0 mg/L NH3 for
almost 100% of the time.
Solids removal:
•
•
•
MBBR DAF unit provided greater
and more consistent solids removal.
Polymer was not needed.
Effluent Ammonia-N (mg/L)
Ammonia Removal
•
MBBR
40%
60%
10.0
1.0
0.1
0.0
0%
20%
80%
100%
Percent Values Less Than or Equal to Indicated Value
Suspended Growth
MBBR
100.0
Effluent TSS (mg/L)
SCENARIO 2 –
70% HONEYWELL
Suspended Growth
10.0
1.0
0%
20%
40%
60%
80%
Percent Values Less Than or Equal to Indicated Value
100%
MBBR provides more stable
performance in terms of
ammonia and TN removal.
NH3-N Removal (%)
•
100.0%
98.0%
96.0%
SG
94.0%
MBBR
92.0%
90.0%
5/19
5/26
6/2
6/9
6/16
TN Removal
100.0%
90.0%
80.0%
TN Removal (%)
SCENARIO 3 –
100% HONEYWELL
Ammonia-N Removal
70.0%
60.0%
50.0%
SG
40.0%
MBBR
30.0%
20.0%
10.0%
0.0%
5/19
5/26
6/2
6/9
6/16
•
•
•
Both systems achieved <1.0 mg/L NH3
about almost 100% of the time.
MBBR achieved effluent ammonia < 0.1
mg/L 75% of the time
Suspended Growth achieved effluent
ammonia < 0.1 mg/L 55% of the time
Solids removal:
•
•
•
MBBR DAF unit provided greater and
more consistent solids removal.
Polymer was not needed.
Effluent Ammonia-N (mg/L)
Ammonia Removal
•
MBBR
40%
60%
10.0
1.0
0.1
0.0
0%
20%
80%
100%
Percent Values Less Than or Equal to Indicated Value
Suspended Growth
MBBR
100.0
Effluent TSS (mg/L)
SCENARIO 3 –
100% HONEYWELL
Suspended Growth
10.0
1.0
0%
20%
40%
60%
80%
Percent Values Less Than or Equal to Indicated Value
100%
SUSPENDED GROWTH
PERFORMANCE OVERVIEW
Kinetic Parameter
(from reactor
Specific
Nitrification Rate profiles)
Normalized to 20 (from batch
Deg C
testing)
μmax at 20 Deg C
Denitrification Rate (normalized
to 14.7 Deg C)
PER Estimate
(at 40% HW)
% Honeywell based on Pilot Testing
Scenario 1, Scenario 2, Scenario 3,
40%
70%
100%
2.22
2.47
2.84
mg NOx-N/g MLVSS*hr
3.43
4.13
4.12
mg NOx-N/g MLVSS*hr
0.7
0.78
0.57
0.49
day-1
0.21
0.1112
0.18
0.19
lb NOx-N/lb MLVSS*day
0.53
0.59
0.41
0.57
(#/day VSS produced)/
(#/day influent cBOD)
0.23
0.25
0.16
0.18
(#/day VSS produced)/
(#/day influent COD)
0.11
0.08
0.02
0.015
0.11
0.09
0.02
0.02
0.09
0.08
0.01
0.01
0.11
0.09
0.02
0.01
# TKN/# VSS
# TKN/# TSS
# TP/# VSS
# TP/# TSS
2.1
Observed Yield
Nitrogen Uptake Rate
Phosphorus Uptake Rate
Units
MBBR PERFORMANCE OVERVIEW
Rate
Denitrification
BOD-Removal
COD-Removal
Nitrification (in BOD-removal zone)
(from reactor
profiles)
Nitrification (in
nitrification zone)
(from batch
testing)
% Honeywell based on Pilot Testing
PER
Estimate
Scenario 1, Scenario 2, Scenario 3,
(at 40% HW)
40%
70%
100%
0.56
0.25
0.30
0.25
4.51
1
9.23
7.01
7.33
2.7
0.27
0.56
0.49
Phosphorus Uptake Rate
g NOx-N/m2-day
g BOD/m2-day
g COD/m2-day
g NH4-N/m2-day
0.48
0.25
0.04
g NH4-N/m2-day
0.84
0.69
0.35
g NH4-N/m2-day
0.61
0.54
0.49
0.73
(#/day VSS produced)/
(#/day influent cBOD)
0.27
0.23
0.20
0.24
0.11
0.08
0.02
0.015
0.10
0.08
0.02
0.02
0.10
0.09
0.03
0.02
0.11
0.09
0.03
0.02
0.63
Observed Yield
Nitrogen Uptake Rate
Units
(#/day VSS produced)/
(#/day influent COD)
# TKN/# VSS
# TKN/# TSS
# TP/# VSS
# TP/# TSS
04
CONCLUSIONS
PILOT TESTING
CONFIRMS SELECTION
OF MBBR SYSTEM
Typically outperformed
Suspended Growth system
More stable
•
•
•
•
•
During loading condition transitions
At higher fractions of Honeywell in
the combined influent
Better solids separation/control
PLANNED SEGREGATED TREATMENT
PROCESS UPGRADES
Segregated Treatment
to Solids
Handling
Screen
MBBR
Honeywell
NaOH
Domestic
Wastewater
Screen
Screen
Industrial
Wastewater
Grit
Removal
Domestic PCs
Grit
Removal
Industrial PCs
WAS
DAFT
SBS
CCT
Denit
Basin
RAS
to Solids
Handling
Aeration Tanks
(HPO)
Secondary
Clarifiers
Post
Aeration
Gravelly Run
05
PROJECT STATUS
© 2014 HDR ©
©
Architecture,
2014
2014 HDR,
HDR,Inc.,
Inc.,
Inc.,all
all
allrights
rights
rightsreserved.
reserved.
reserved.