This document discusses various technologies for removing nitrogen from sludge dewatering liquor, including: - Anaerobic digestion, which typically reduces nitrogen levels but additional treatment may be needed. - Reject water handling alternatives such as doing nothing, exporting, attenuating through flow equalization, or treating through integrated or separate treatment processes. - Integrated treatment processes include in-line or off-line prenitrification of filtrate while separate treatment examples provided are SHARON, DEMON, and ammonia stripping processes. Capital and nitrogen removal costs are provided for some example full-scale facilities using these different technologies.

1. Technologies for Sustainable
Wastewater Treatment
Nitrogen Removal from Sludge
Dewatering Liquor

2. March 20, 2012 WATERCON 2012 2
Primary
Settler
Primary Sludge
(30 lbs. N)
Waste Activated Sludge
(140 lbs. N)
For every 1 mil. gal. of water treated:
330 lbs. N

3. March 20, 2012 WATERCON 2012 3
Anaerobic digestion
Primary
Settler
Sludge
Thickener
Anaerobic
Digester
Sludge
DewateringCake
N = 300 to 1,000 mg/L
~10% of influent load

4. 4
Anaerobic digestion +
imported sludge
Primary
Settler
Sludge
Thickener
Anaerobic
Digester
Sludge
DewateringCake
N x 2N x 3N x 1
March 20, 2012 WATERCON 2012 4

5. 5
Anaerobic digestion +
solids pretreatment
Primary
Settler
Sludge
Thickener
Anaerobic
Digester
Sludge
DewateringCake
N = 1,500 to 3,000 mg/L
March 20, 2012 WATERCON 2012 5

6. Reject Water Handling Alternatives
• Do Nothing
• Export
• Attenuate
• Treat
– Integrated treatment
– Separate treatment
March 20, 2012 WATERCON 2012 6

7. Do Nothing
WAS
RAS
Reject
Water
March 20, 2012 WATERCON 2012 7

8. Boulder 75th Street Wastewater
Treatment Facility
Source: Fevig, et al, “Centrate Equalization – What You Don’t Control Can Hurt You”
WEFTEC 2011.

9. Export
• Regional districts w/ multiple plants
• To less sensitive watersheds
• To underloaded facility with capacity to
handle additional solids
• New York City

10. Attenuation
• Flow equalization
• Continuous operation
• Stand-alone or incorporated with treatment

11. Source: Brown and Caldwell (1979) Equalization of flow in Wastewater Treatment.
Report prepared for the US EPA, EPA-600/2-79-096.

12. Don’t Reject the Idea of Treating
Reject Water*
*Janus, H.M., and vanderRoest, H.F. (1997). Don't reject the idea of treating reject water. Wat.
Sci. Tech. 35 (10)27-34.
• Highly Concentrated - Small tank volumes
• Warm – Short SRT’s
• Bioaugmentation - Stable off-line source to
boost main-stream SRT
March 20, 2012 WATERCON 2012 12

13. Integrated Treatment – in-line
RAS
f
1 - f
March 20, 2012 WATERCON 2012 13

14. Integrated Treatment – off-line
Nitrate to Headworks
March 20, 2012 WATERCON 2012 14

15. Integrated Treatment: in-line
Full-scale facility
Capacity
(mgd) Process Drivers
NYC
26th Ward WPCP
85 AT-3
Effluent Total Nitrogen, centralized
solids handling (bioaugmentation)
Los Angeles
Valencia WRP
15 -
Effluent Total Nitrogen, centralized
solids handling
Appleton, WI
WWTP
15.7 BAR Effluent Ammonia (bioaugmentation)
Inland Empire
Carbon Canyon
9.5 Carbon Canyon TIN bubble permit
Lincoln, NE
WTF
24 Prenitrification Effluent Ammonia (bioaugmentation)
March 20, 2012 WATERCON 2012 15

16. Lincoln, NE Theresa St. WWTF
Source: Sova, R. et al, WEFTEC 2008.March 20, 2012 WATERCON 2012 16

17. Lincoln, NE Theresa St. WWTF
March 20, 2012 WATERCON 2012 17

18. Solution: Prenitrification of Filtrate
• Alkalinity from RAS
• Increased temperature – + 20% growth rate
• Enriched source of nitrifiers to increase
effective SRT in main-stream
• Up to 82% removal demonstrated at 10% to
100% RAS (HRT = 10.5 to 3.2 hours)
March 20, 2012 WATERCON 2012 18

19. Integrated treatment: off-line
Full-scale Facility
Capacity
(mgd) Process Drivers
Phoenix 91st Ave.
Multi-Cities WWTP
230
Activated Sludge
(flow-through)
Digester Upgrade,
Effluent Total Nitrogen, odor
control
Winnipeg, Canada
North End WPCC
53 SBR
Centralized solids handling,
Effluent Ammonia & Total
Nitrogen (Bioaug./cold)
Dallas
Southside WWTP
110
Activated Sludge
(flow-through)
Centralized solids handling
Richmond, VA
WWTP
80 In-Nitri®
Effluent Total Nitrogen
(Bioaug./storm-cold)
Muncie, IN
WPCF
24
Activated Sludge
(flow-through)
Effluent Ammonia
March 20, 2012 WATERCON 2012 19

20. Phoenix 91st Ave. Multi-Cities WWTP
• Upgrade to multi-phase digestion
– 1,300 mg NH3-N/L (27% of PE)
• 10 mg / L Total N effluent permit limit.
• H2S emission limit at property line
March 20, 2012 WATERCON 2012 20

21. 91st Ave. Multi-Cities Centrate
Treatment Facility
Source: Husband, J. et al, Water Science & Technology, vol. 61 n. 5, 2010March 20, 2012 WATERCON 2012 21

22. Autotrophic Sulfur Oxidization
Nitrate
2NO3
-
+ 5HS
-
+ H2O = 5S + N2 +7OH
-
5S + 6 NO3
-
+ 4OH
-
= 5 SO4
-2
+ 3N2 + 2H2O
Nitrite
2NO2
-
+ 3HS
-
+ H2O = 3S + N2 +5OH
-
3S + 6NO2
-
= 3SO4
-2
+3N2
Thiobacillus denitrificans & Thiomicrospira denitrificans
are two examples of autotrophic sulfur oxidizing bacteria

23. 91st Avenue Multi-Cities WWTP
Raw Vs. Pri Effl Ammonia (mg/L)
20
24
28
32
36
40
2005 2006 2007 2008 2009
Raw Ammonia (mg/L) Primary Effluent Ammonia (mg/L)
H: 91 Monthly Averages.xls
CTF on-line
03/24/08
Source: Husband, J. et al, Water Science & Technology, vol. 61 n. 5, 2010March 20, 2012 WATERCON 2012 23

24. Solution: Discharge to headworks
to oxidize sulfides
March 20, 2012 WATERCON 2012 24
0
5
10
15
20
25
30
35
40
45
GaseousH2S,ppm
Time
Centrate Treatment Off
Average H2S - 12 ppm
Maximum H2S - 32 ppm
Centrate Treatment On
Average H2S - 6 ppm
Maximum H2S - 21 ppm
Source: Husband, J. et al, Water Science & Technology, vol. 61 n. 5, 2010

25. Separate Treatment
Full-scale Facility
Capacity
(mgd)
Process Drivers
NYC Ward’s Island 230 SHARON
Total Nitrogen TMDL (Long Island
Sound), centralized solids
handling
HRSD York River
Treatment Plant
15 DEMON
Total Nitrogen TMDL
(Chesapeake Bay)
ASA, Alexandria, VA 54 DEMON
Total Nitrogen TMDL
(Chesapeake Bay)
NYC 26th Ward 85 ARP
NYCDEP Nitrogen Control Plan
(Jamaica Bay), centralized solids
handling
March 20, 2012 WATERCON 2012 25

26. 1 mole Ammonia
(NH3 / NH4
+)
1 mole Nitrite
(NO2
-)
1 mole Nitrate
(NO3
-)
1 mole Nitrite
(NO2
-)
1/2 mole Nitrogen gas
(N2)
75% O2
25% O2
40% Carbon
60% Carbon
Nitrification /
Denitrification
Aerobic Anoxic
March 20, 2012 WATERCON 2012 26

27. 1 mole Ammonia
(NH3 / NH4
+)
1 mole Nitrite
(NO2
-)
1 mole Nitrate
(NO3
-)
1 mole Nitrite
(NO2
-)
1/2 mole Nitrogen gas
(N2)
75% O2
25% O2
40% Carbon
60% Carbon
Nitritation /
Denitritation
Aerobic Anoxic
March 20, 2012 WATERCON 2012 27

28. Nitrogen removal over nitrite
• Temperature
• D.O.
• pH
March 20, 2012 WATERCON 2012 28

29. Nitritation-Denitritation
• Continuous / no sludge retention (SHARON®) -
13 facilities
• SBR (B.A.B.E. ®, STRASS) – 2 facilities
• North America – 1 SHARON® (NYC)
March 20, 2012 WATERCON 2012 29

30. SHARON® configurations
Complete Mix
Plug Flow
Concentric
MeOH
March 20, 2012 WATERCON 2012 30

31. WWTP Zwolle (NL) SHARON® reactors
• 200,000 p.e.
• 160,000 gpd / 900 lbs.
N / day
• 2 reactors -238,000 gal.
/ 119,000 gal.
Source: Mulder, J.W., Duin, J., et al, “Full-scale experience with the SHARON process through
the eyes of the operators”, WEFTEC 2006.
March 20, 2012 WATERCON 2012 31

32. SHARON® operation
Source: Mulder, J.W., Duin, J., et al, “Full-scale experience with the SHARON process through
the eyes of the operators”, WEFTEC 2006.
March 20, 2012 WATERCON 2012 32

33. 1 mole Ammonia
(NH3 / NH4
+)
1 mole Nitrite
(NO2
-)
1 mole Nitrate
(NO3
-)
1 mole Nitrite
(NO2
-)
1/2 mole Nitrogen gas
(N2)
75% O2
25% O2
40% Carbon
60% Carbon
Aerobic Anoxic
Deammonification
Anaerobic
March 20, 2012 WATERCON 2012
1/2 mole Nitrite
(NO2
-)
33
1/2 mole Ammonia
(NH3 / NH4
+)
37.5% O2

34. Deammonification
• SBR (DEMON®) 11 facilities
• MBBR 2 facilities
• Upflow granulation 7 facilities
• North America – 2 (under construction)
March 20, 2012 WATERCON 2012 34

35. March 20, 2012 WATERCON 2012 35
Alexandria Sanitation Authority AWTF
Source: Johnson, T, et al, A Universal SBR Design Concept for Sidestream Nitrogen
Removal, North Carolina AWWA-WEA 2010 Annual Conference.

36. WWTP Strass, Austria
Source: Bernhard Wett, Water Science & Technology, Vol. 56 No. 7, 2007.
March 20, 2012 WATERCON 2012 36

37. DEMON® Operation
Source: Bernhard Wett, Water Science & Technology, Vol. 56 No. 7, 2007.
March 20, 2012 WATERCON 2012 37

38. DEMON® energy
Source: Bernhard Wett, Water Science & Technology, Vol. 56 No. 7, 2007.
March 20, 2012 WATERCON 2012 38

39. March 20, 2012 WATERCON 2012 39
Ammonia Stripping
• Air stripping – 8 facilities
• Steam stripping – 1 facility
• Vacuum distillation (ARP) – 1 (under
construction)

40. ARP
Courtesy of ThermoEnergy Corporation
March 20, 2012 WATERCON 2012 40

41. Costs
Process
Capital Cost
N removed
(lbs./day)
SHARON - NYC $71.5 million 10,000
Integrated
Treatment -
Winnipeg
$25 million 3,000
ARP - NYC $27 million 6,600
March 20, 2012 WATERCON 2012 41

42. March 20, 2012 WATERCON 2012 42
Robert Smith, P.E., BCEE, Ph.D.
rocsmith@juno.com