2. COMPARISON OF MBBR AND Suspended growth BNR Performance at the HRWTF
Erika L. Bailey, PE
NC AWWA WEA Annual Conference
November 16, 2015

3. 01 02 03 04 05 Introduction, Drivers, and Challenges
Segregated Treatment Concept 03
MBBR / Suspended Growth Comparison 04
Conclusions 05
Project Status

4. Introduction, PROJECT DRIVERS, AND CHALLENGES01
Introduction, PROJECT DRIVERS, AND CHALLENGES

5. 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

6. HRWTF Existing liquid treatment Process
“HAP” Foul Condensate
VAWCO
Gravelly Run
RockTenn
Industrial
Headworks
Reaeration
Hercules
Denit. Basin
Industrial Primary Clarifiers
HPO Aeration Tanks
Evonik
Final
Clarifiers
RAS
Honeywell
HOCl
Domestic
Domestic Headworks
2012 Improvements
(Phase 1)
Domestic Primary Clarifiers & Chlorine Contact Tanks

7. Total Nutrient Discharge Load by Year (Mlb/yr)
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: 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) TP TN
HRWTF Waste
Load Allocation
0.075
1.83
2005 ND
1.9
2006
1.55
2007
1.7
2008
0.048
1.57
2009
0.013
1.88
2010
0.028
2.02
2011
0.020
1.77

8. Nitrogen Removal is Challenge at hRWTF
Exceeds upper temperature limit for stable nitrification
High influent temperatures exceed 37 ºC
Cooling creates air permitting challenges
High concentration of VOCs
Impacts process performance stability
Variable influent wastewater characteristics
Slower nitrification rates expected (larger aeration tanks)
Wastewater contains nitrification inhibitors

9. Addressing BNR Challenges: Segregated Treatment Concept02
Addressing BNR Challenges: Segregated Treatment Concept

10. 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

11. 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
Final Effluent
Domestic
Honeywell
Biological
Nutrient
Removal
Secondary
Treatment
Combined Influent
Total
Influent
Ashland RockTenn VAWCO Evonik
Primary
Segregated Stream
Is there any issue naming all these industrial? Check with Hopewell, if you haven’t yet.

12. MBBR: Moving Bed Biofilm Reactor
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
Bullets look off. What’s supposed to be happening here?
Anoxic Cell
BOD Removal Cell
Nitrification Cells

13. 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

14. Comparison of MBBR / suspended Growth Performance03
Comparison of MBBR / suspended Growth Performance

15. Pilot Testing Configuration

16. Pilot Testing Conditions
Scenario
Description
Influent % Honeywell 1
40% Design Avg
19% 2
70% Design Avg
29% 3
100% Design Avg
37%
What is the ‘1’ superscript for?
What does HW stand for?
What is design average?
What is the domestic portion?
I don’t quite understand this.

17. Scenario 1 – 40% Honeywell
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.
This was done initially to purge any inhibitory compound remaining in the system following the nitrification inhibition event on February 28th but was left off for an additional three weeks to test a theory concerning MEKO.
Difficult to read grey-shaded tables.

18. Scenario 1 – 40% Honeywell Ammonia reduction Solids removal
Both systems achieved <1.0 mg/L NH3 for 85% of the time.
Solids removal
MBBR DAF unit provided greater and more consistent solids removal.
Polymer was not needed.
Both systems achieved an effluent ammonia concentration less than 1.0 mg/L for 85% of the time.
Unexplained ammonia breakthrough in the MBBR is the reason for the sharp peak as the MBBR curve moves from the 90% to the 100% probability point on the x-axis.
MBBR DAF unit provided greater and more consistent solids removal when compared to the Suspended Growth clarifier. No polymer addition to the DAF was required to achieve this level of TSS removal.

19. Scenario 2 – 70% Honeywell MBBR Suspended Growth
More stable removal of ammonia and TN
Suspended Growth
Drop in nitrification performance due to an unexplained loss of biomass
The MBBR provides more stable performance in terms of ammonia, TN, and COD removal at this testing condition.
Suspended Growth system experienced a drop in nitrification performance that did not occur with the MBBR due to an unexplained loss of biomass which appeared to be a result of biomass deflocculation.

20. Scenario 2 – 70% Honeywell
Sudden increase in effluent TSS from the Suspended Growth system
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.
Sudden increase in effluent TSS from the Suspended Growth system had a significant effect on the MLSS concentration and SRT.
Based on the observed drop in MLSS, it is estimated that the SRT may have reached as low as 9 days (7 day aerobic SRT).
Nitrifier washout would not usually be expected at the operating temperature at this time (18 degrees Celsius); however, the continuous nitrification inhibition experienced in the Suspended Growth system would make it more sensitive to the low SRT impacts.

21. Scenario 2 – 70% Honeywell Ammonia Removal Solids removal:
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.
The MBBR achieved an effluent ammonia concentration less than 1.0 mg/L for nearly 100% of the time.
The Suspended Growth system achieved an effluent ammonia concentration less than 1.0 mg/L for approximately 70% of the time.
The MBBR DAF unit consistently is able to provide greater and more consistent solids removal when compared to the Suspended Growth clarifier. No polymer addition to the DAF was required to achieve this level of TSS removal.

22. Scenario 3 – 100% Honeywell
MBBR provides more stable performance in terms of ammonia and TN removal.

23. Scenario 3 – 100% Honeywell Ammonia Removal Solids removal:
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.

24. Suspended Growth Performance Overview
Kinetic Parameter
PER Estimate
(at 40% HW)
% Honeywell based on Pilot Testing
Units
Scenario 1,
40%
Scenario 2,
70%
Scenario 3,
100%
Specific Nitrification Rate Normalized to 20 Deg C
(from reactor profiles)
2.1
2.22
2.47
2.84
mg NOx-N/g MLVSS*hr
(from batch testing)
3.43
4.13
4.12
μmax at 20 Deg C
0.7
0.78
0.57
0.49
day-1
Denitrification Rate (normalized to 14.7 Deg C)
0.21
0.1112
0.18
0.19
lb NOx-N/lb MLVSS*day
Observed Yield
0.53
0.59
0.41
(#/day VSS produced)/
(#/day influent cBOD)
0.23
0.25
0.16
(#/day influent COD)
Nitrogen Uptake Rate
0.11
0.09
# TKN/# VSS
0.08
# TKN/# TSS
Phosphorus Uptake Rate
0.02
0.01
# TP/# VSS
0.015
# TP/# TSS
Won’t be able to read the table. Suggest 2 slides?

25. MBBR Performance Overview
Rate
PER Estimate
(at 40% HW)
% Honeywell based on Pilot Testing
Units
Scenario 1,
40%
Scenario 2,
70%
Scenario 3,
100%
Denitrification
0.56
0.25
0.30
g NOx-N/m2-day
BOD-Removal
4.51 -
g BOD/m2-day
COD-Removal
9.231
7.01
7.33
2.7
g COD/m2-day
Nitrification (in BOD-removal zone)
0.63
0.27
0.49
g NH4-N/m2-day
Nitrification (in nitrification zone)
(from reactor profiles)
0.48
0.04
(from batch testing)
0.84
0.69
0.35
Observed Yield
0.61
0.54
0.73
(#/day VSS produced)/
(#/day influent cBOD)
0.23
0.20
0.24
(#/day influent COD)
Nitrogen Uptake Rate
0.11
0.10
# TKN/# VSS
0.08
0.09
# TKN/# TSS
Phosphorus Uptake Rate
0.02
0.03
# TP/# VSS
0.015
# TP/# TSS
Won’t be able to read the table. Suggest 2 slides?

26. 04
Conclusions

27. 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

28. Planned Segregated Treatment Process Upgrades
Grit
Removal
Screen
Domestic PCs
Industrial PCs
CCT
Denit Basin
Post Aeration
Gravelly Run
WAS
RAS
to Solids Handling
Secondary Clarifiers
Aeration Tanks
(HPO)
Domestic Wastewater
Industrial Wastewater
MBBR
Honeywell
DAFT
NaOH
SBS

29. 05
Project Status