virtual e-curve method development of an innovative methodology for hydraulic residence time...
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Virtual E-Curve Method
Development of an Innovative Methodology for Hydraulic Residence Time Distribution Analysis – Virtual E-Curve Method
November 17, 2015
Don Lee, Ph.D., P.E. Senior Wastewater Process Engineer
Project Manager
AECOM, Greenville SC
Tom Leland P.E. Ovivo USA, Salt Lake City, UT
Steven A. Yeats, P.E. Jones Edmunds & Associates, Gainesville FL
Ben Koopman, Ph.D. University of Florida, Gainesville FL
OUTLINEIntroductionVirtual E-Curve MethodApplication to Full-Scale Tracer StudySummary and Conclusions
OUTLINEIntroductionVirtual E-Curve MethodApplication to Full-Scale Tracer StudySummary and Conclusions
Lee et al., Virtual E-Curve Method Page 4
Introduction: Mixing Performance Evaluation Completely Stirred Tank Reactor (CSTR) Conditions
Wastewater-mixed liquor contact
Mixed liquor suspension
Dead zone and short-circuiting minimization
Assumption for most BNR modeling (ASMs and simulation programs)
Ease of Reactor Characterization
Hydraulic Residence Time Distribution (HRT) Analysis with Tracer Study
Lee et al., Virtual E-Curve Method 5
t
C
t
Q QIdeal CSTRwith slug load tracer input
Two Ideal CSTRs in series with recirculation flow
Q Q + QR Q
QR
HRT Analysis with influent interferences
t
C t ??
Lee et al., Virtual E-Curve Method 6
Live Oak WWTF Carrousel® denitIR® System, Live Oak, FL
Anoxic Basin (0.34 MG)
MixerInfluent (Q)
RAS (QR=Q)
Aeration Basin (0.834 MG)
denitIR® Gate
Aerators
Mixed Liquor to Clarifier (QR+Q=2Q)
Reclaimed WaterIR flow w/o influent
AnoxicBasin
AerationBasin Clarifier
MLE Process
RAS
INF EFF
WAS
IR
Internal Recirculation (QIR = 3Q)Combined Influent 5Q
OUTLINEIntroductionVirtual E-Curve MethodApplication to Full-Scale Tracer StudySummary and Conclusions
Lee et al., Virtual E-Curve Method 8
Virtual E-Curve Method (adapted from “Virtual Batch Curve” of Lee et al., 2008)
1221,1 C
VQC
VQ
dtdC
dtdC
ttCC
tC 21,1
12
1,12,121,1
1,221,121,1 CVQ
tC
tC Virtual
tt
CCC Virtual
V
21,1
1,12,1
)(/)(/ 2,22,12,132,132,1 CVQCCVQ
tC
tC
VVirtual
tt
CCC Virtual
VV
32,1
2,13,1
Q
Q
V1 V2 C2C1t
C t ??
t
C
t
Re-integrate a virtual C-curve using adjusted rates of changes as if there were NO influent interferences.
t
Lee et al., Virtual E-Curve Method 9
Virtual E-Curve Method: applied to theoretical reactor behaviors simulated with programming
0
0.2
0.4
0.6
0.8
1
0 1 2 3 4
C
Time (hours)
Tracer concentration in an influenced CSTR
Tracer concentration in the influent
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 2 4 6 8 10
E
Time (hours)
E Curve of non-influenced CSTR
E Curve of influenced CSTR from VirtualE-Curve Method
Lee et al., Virtual E-Curve Method 10
Sensitivity analyses: Initial (theoretical) vs actual volumeNumerical methodsIntegration step-sizeSampling intervals
Verification of Virtual E-Curve Method
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 2 4 6 8 10
E
Time (hours)
E Curve of non-influenced CSTR
E Curve of influenced CSTR from VirtualE-Curve Methodt
C t ??
Q Q + QR Q
Tested various types of influent interferences with additional simulations:
Recycle flowsContinuous or Sudden influent
concentration changesVarying influent flowrate
OUTLINEIntroductionVirtual E-Curve MethodApplication to Full-Scale Tracer StudySummary and Conclusions
Lee et al., Virtual E-Curve Method 12
Full Scale Tracer Study
INF Sampling
EFF Sampling
Slug Load Tracer Input
Anoxic Basin (0.34 MG)
Mixer
Aeration Basin (0.834 MG)
Aerators
INF
EFF
Lee et al., Virtual E-Curve Method 13
Sampling and Onsite Measurement
Lee et al., Virtual E-Curve Method 14
EFF
INF
Aerators
Anoxic Basin (0.34 MG) with a Mixer
Aeration Basin (0.834 MG)
Full Scale Test Results
t
C t ??
Q Q Q
Slug Load Tracer Input
Lee et al., Virtual E-Curve Method 15
Full Scale Test Results
0
50
100
150
200
250
300
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0Time (hours)
Rho
dam
ine
WT
(ppb
)
Anoxic Basin Influent (test result)Anoxic Basin Effluent (test result)
Anoxic Basin Influent (theoretical)Anoxic Basin Effluent (theoretical)
Lee et al., Virtual E-Curve Method 16
Application of Virtual E-Curve Method to Test Results
0
0.5
1
1.5
2
2.5
3
3.5
4
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0Time (hours)
E
E Curve from Ideal CSTR
E Curve from Virtual E-Curve Method
44 min average (115% theoretical HRT)
2.5 CSTRs in series – NOT an ideal CSTR
Lee et al., Virtual E-Curve Method 17
Virtual E-Curve Method Error Estimations with Uniform Tanks-in-Series Modeling
0
10
20
30
40
50
60
0 5 10 15 20 25Number of Ideal CSTR in Series
% E
rror
of V
irtua
l E-C
urve
Met
hod
250% Anoxic Volume100% Anoxic Volume80% Anoxic Volume30% Anoxic Volume
Lee et al., Virtual E-Curve Method 18
Virtual E-Curve MethodError Adjustment with Non-Uniform Tanks-in-Series Modeling
Center CSTR (50%)Inlet PFR tanks in series(25%)
Outlet PFR – tanks in series (25%)
Inlet Slowly Mixed Zone (12.5-25%)
Outlet Slowly Mixed Zone (12.5-25%)
CenterRapidly Mixed Zone (50-75%)
Tracer Injection Location
Lee et al., Virtual E-Curve Method 19
Virtual E-Curve MethodError Adjustment with Non-Uniform Tanks-in-Series Modeling
91% theoretical HRT (reactor volume utilization)
0
0.5
1
1.5
2
2.5
3
3.5
4
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0Time (hours)
E
E Curve from Ideal CSTR
E Curve from Virtual E-Curve Method
E Curve from Non-Uniform Tanks-in-Series Modeling Percent Error = 23%
OUTLINEIntroductionVirtual E-Curve MethodApplication to Full-Scale Tracer StudySummary and Conclusions
Lee et al., Virtual E-Curve Method 21
Summary and Conclusions
Virtual E-Curve method allows hydraulic residence time distribution analysis of ideal CSTRs with influent interferences.
Integration methodologies, step-sizes and sampling intervals affect the accuracy of Virtual E-Curve method.
Errors associated with non-ideal reactor behaviors could be adjusted using advanced reactor modeling.
Virtual E-Curve Method
Questions?
Don Lee, Ph.D., P.E.Senior Wastewater Process Engineer/Project Manager
AECOM, Greenville SC 864-234-3583don.lee02@aecom.com
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