UNCONVENTIONAL PHOSPHORUS REMOVAL STICKNEY BIOLOGICAL PHOSHORUS REMOVAL AND RECOVERY
METROPOLITAN WATER RECLAMATION DISTRICT OF GREATER CHICAGO
B&V PROJECT NO. 182019 SUBTASK A110 - February 2014
STICKNEY WATER RECLAMATION PLANT
Design capacity: 1,400 mgd
Existing TP Effluent: 1-2mg/L
New TP Effluent Limit of 1.0 mg/L
• Optimizing biological phosphorus removal
• Minimizing phosphorus return loads (24%) from recycle streams
Phosphorus need (finite resource):
Population growth increases the need for phosphorus fertilizers
TOWARD A SUSTAINABLE PHOSPHORUS CYCLE
Phosphorus removal:
Point sources: more stringent phosphorus limits at WWTP’s
Recovery = resource and revenue source
3
UNINTENDED STRUVITE FORMATION
WHAT HAPPENS IN THE ANAEROBIC ZONE
WRONG!!!!!!!!!
• We were cultivating less productive PAOs, mostly of the species of Accumulibacter
• They prevailed since conditions were not ideal for more aggressive species like Tetrasphaera
• Tetrasphaera can ferment glucose and amino acids and other higher carbon forms and store phosphorus
• They actually produce VFA that allow a population of Accumulibacter to grow alongside them
• They can denitrify under anoxic conditions
• Why did we not grow them – not deep enough anaerobic conditions
2
6
MIXED LIQUOR FERMENTER (MLF)
• From experience at a number of plants fermentation of some of the mixed liquor was successful in achieving BioP and reducing nitrates
• Mostly influent wastewater has very low VFA and even low rbCOD that could be fermented in the anaerobic zone
• Solution – ferment some of the mixed liquor as happened in original pilot plant
100 m3/d pilot 1972
WESTBANK WITH FERMENTER
TN < 6 mg/ℓ BOD < 5 mg/ℓ TSS < 2 mg/ℓ TP < 0.15 mg/ℓ
Westside Kelowna BC (Westbank)
X
WESTBANK WWTP
Primary Anaerob Anoxic 1 Anoxic 2 Anoxic 3 Aerobic 1 Aerobic 2 Aerobic 3
5.36 20.56 2.20 1.84 1.60 0.50 0.20 0.03 Bioreactor Profile
Phosphorus by Zone
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
Pri
mar
y
An
aero
b
An
oxi
c 1
An
oxi
c 2
An
oxi
c 3
Ae
rob
ic 1
Ae
rob
ic 2
Ae
rob
ic 3
Ph
osp
ho
rus
mg
/L
Note P uptake in Anoxic Zone
Tetrasphaera can denitrify
MIX OF ORGANISMS IN WESTSIDE PLANT
FISH Image from WR WWTP Sludge with EUB mix (all bacteria) Shown in Green, Tet2-174 (Tetrasphaera clade 2B) in Orange, and Tet3-654 (Tetrasphaera clade 3) in Red.
EXPERIMENT AT DENVER METRO
Cavanaugh, L., Carson, K., Lynch, C., Phillips, H., Barnard, J. and McQuarrie, J. (2012) A Small Footprint Approach for Enhanced Biological Phosphorus Removal: Results from a 106 mgd Full-Scale Demonstration. Proceedings of the 85th Annual Water Environment Federation Technical Exhibition and Conference, New Orleans, LA, October 2012.
PHOSPHORUS REMOVAL BY RAS FERMENTATION – DENVER METRO
0
5
10
15
20
25
0.0
0.5
1.0
1.5
2.0
2.5
3.0
10
/4/2
01
1
10
/6/2
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1
10
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1
10
/10
/20
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/1/2
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1
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/11
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/1/2
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/5/2
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1
mg-
TSS/
L
mg-
P/L
NSEC Effluent TP
NSEC Effluent PO4-P
NSEC Effluent TSS
PHOSPHORUS REMOVAL WITH SIDE-STREAM FERMENTATION
Iowa Hill CO plant – From Chris Maher
0
0.05
0.1
0.15
0.2
0.25
0.3
Eff
lue
nt
Ort
ho
P m
g/L
9/8/2011 9/9/2011 9/10/2011
CAROUSEL PLANT HENDERSON NV 60 ML/D – UPGRADED TO BNR
Ortho-P for May 2010
0
0.1
0.2
0.3
0.4
0.5
5/1/
2010
5/2/
2010
5/3/
2010
5/4/
2010
5/5/
2010
5/6/
2010
5/7/
2010
5/8/
2010
5/9/
2010
5/10
/201
0
5/11
/201
0
5/12
/201
0
5/13
/201
0
5/14
/201
0
5/15
/201
0
5/16
/201
0
5/17
/201
0
5/18
/201
0
5/19
/201
0
5/20
/201
0
5/21
/201
0
5/22
/201
0
5/23
/201
0
5/24
/201
0
5/25
/201
0
5/26
/201
0
5/27
/201
0
5/28
/201
0
5/29
/201
0
5/30
/201
0
Ph
os
ph
oru
s (
mg
/L)
ANA Eft SPS SCC Final Eft
Switching off a mixer in the anaerobic zone resulted in In-plant Fermentation
WHY DID WE MISS IT?
• Need ORP of -300 mV – most anaerobic zones struggle to get -150 mV
• Impossible to achieve with nitrates or DO anywhere
• Most plants were over-mixed with turbulent surface entraining air
• Standard mixing energy 0.6 hp/kcf – need 0.08 hp/kcf (huge saving in energy)
• Too much air entrained in primary effluent
• Too much primary effluent per se
• Mixing with air – No-no
15
STICKNEY WATER RECLAMATION PLANT
Mix with air
Airlift RAS pumps
Mix with air
Mix with air High DO
High RAS return
P1 P2 P3 P4 M
ixin
g ch
ann
el
RA
S C
han
ne
l PE
RAS
D_W
AS
D_RS D
_MC
C
D4_MC
D4
_P1
E D
4_P
1
D4
_P2
E
D4
_P4
E
D_SE DO (mg/L) D4_P1 (1) D4_P1E (2) Diffuser Opp-diffuser
min 0.17 3.15 0.91 max 2.01 9.00 8.66
average 0.77 7.73 6.14 Average before 0.76 1.35 0.42
1
2
CONTINUOUS DO MONITORING IN AEROBIC ZONE
POSSIBLE EFFECT OF BAFFLE ON SLUDGE ACCUMULATION IN THE ANAEROBIC ZONE
2
18
Anaerobic Zone
Anaerobic
• Pursue ways to increase rbCOD
• Store sludge in primaries
• Gravity thickeners as fermenters
• Dedicated fermenters
Reducing # of PST will result in more pCOD – not efficient
Keep all PST but carry a sludge blanket
RECOMMENDATIONS
• Breweries, soft drinks plant wastes have high carbon rbCOD. If pre-treated negotiate for discharging some without charges
• Install controls for RAS recycle to minimal
• Control DO in 4th pass
• Control discharge of Alum and Fe salts
• Automate air mixing of anaerobic zone – replace with mixers
• Install baffles between anaerobic and main aeration or more baffles to trap sludge for fermentation
• CONTROL THE ORP BELOW -300 mV in sludge blanket
RECOMMENDATIONS
20
2
PEARL® PROCESS TECHNOLOGY
Technology Scaled Up:
Reactor size for Stickney WRP
• Durham, OR
• Saskatoon, Saskatchewan
• HRSD, VA
• Edmonton, Alberta
• York, PA
• Rock Creek, OR
• Madison, WI
• Slough, United Kingdom
TECHNOLOGY SCALED UP:
OPERATING FACILITIES:
Reactor size for Stickney WRP
22
SOLIDS HANDLING AT STICKNEY WRP
Sludge
Screens
Sludge
Concentration
Tanks
Pre
Digestion
Centrifuges
Sludge
Holding
Digesters
Sludge
Holding
Tank
Post
Digestion
Centrifuges
Dryers
(MBM)
To Salt Creek
Interceptor Overflow Centrate
Centrate
Supernatant
Lagoons To Argo
Interceptor
Railcars Dewatered
Biosolids
Preliminary Settling Tanks
WAS (Batteries A,B,C,D)
O’Brien WRP
Sludge (PS & WAS)
Imhoff Sludge
To Southwest Interceptor
24
Owner to self-implement WASSTRIP
STUDY PHASE RESULTS
25
• Option 1: P recovery from centrifuge centrate post digestion
• Option 2: P recovery using WASSTRIP to release phosphate pre-digestion (includes post-digestion centrate as ammonia source)
• Option 3: P recovery from LASMA returns
• Option 4: Combination of Options 2 and 3, recovering P from all 3 sidestreams
P-RECOVERY OPTIONS
26
WASSTRIP INTEGRATION 1. Updated concept
2. Schedule/status
27
WASSTRIP OPTION
Principle of Operation
• Engineered P release of waste activated sludge (WAS).
• Carbon for release can come from primary sludge fermentate, external source, or endogenously.
• Liquid portion from reactor (high in P & Mg) blended with centrate (high in NH3) before entering P recovery reactor.
Benefits
• Increases P recovery
• Reduces struvite formation in digesters
• Reduces P content in biosolids
• Less Mg addition to P recovery process
Disadvantages
• Addition of sizable reactor for process
28
OPTION 2 - WASSTRIP
29 Additional Benefit – Reduced Struvite Formation in Dewatering
2/26/2014
CONSTRUCTION PROGRESS Progress Photos and Current Status
30
SITE PRIOR TO START OF WORK
WORK TENT ERECTION
WORK TENT
WORK TENT
POST-DIGESTION PS MUD MAT
REACTORS IN FABRICATION
WINTER CONDITIONS
REACTOR SEGMENTS BEING DELIVERED
CONCRETE WORK IN TENT
CHEMICAL TANK DELIVERY
REACTOR CONES ON SITE
ASSEMBLY OF FIRST OSTARA REACTOR
CONTINUED REACTOR FIT-UP
CONTINUED REACTOR FIT-UP
PIPE BRIDGE ERECTION
BUILDING FRAME ERECTION
10,000 REACTOR Black & Veatch
50
TOP OF REACTOR
51
SILOS FOR DIFFERENT PEARL SIZES
52
SEPARATION OF CRYSTALS BEFORE HARVESTING
53
2
54
2
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