1. 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

2. OUTLINE Introduction Virtual E-Curve Method Application to Full-Scale Tracer Study Summary and Conclusions

4. Lee et al., Virtual E-Curve Method Introduction: Mixing Performance Evaluation 4 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

5. Lee et al., Virtual E-Curve Method 5 t C t Q Q Ideal CSTR with slug load tracer input Two Ideal CSTRs in series with recirculation flow Q Q + Q R Q QRQR HRT Analysis with influent interferences t C t ??

6. Lee et al., Virtual E-Curve Method Live Oak WWTF Carrousel ® denitIR ® System, Live Oak, FL 6 Anoxic Basin (0.34 MG) Mixer Influent (Q) RAS (Q R =Q) Aeration Basin (0.834 MG) denitIR ® Gate Aerators Mixed Liquor to Clarifier (Q R +Q=2Q) Reclaimed Water IR flow w/o influent Anoxic Basin Anoxic Basin Aeration Basin Aeration Basin Clarifier MLE Process RAS INF EFF WAS IR Internal Recirculation (Q IR = 3Q) Combined Influent 5Q

7. OUTLINE Introduction Virtual E-Curve Method Application to Full-Scale Tracer Study Summary and Conclusions

8. Lee et al., Virtual E-Curve Method 8 Virtual E-Curve Method (adapted from “Virtual Batch Curve” of Lee et al., 2008) Q Q Q V1V1 V2V2 C2C2 C1C1 t C t ?? t C t Re-integrate a virtual C-curve using adjusted rates of changes as if there were NO influent interferences. tt

9. Lee et al., Virtual E-Curve Method Virtual E-Curve Method: applied to theoretical reactor behaviors simulated with programming 9 0 0.2 0.4 0.6 0.8 1 01234 C Time (hours) Tracer concentration in an influenced CSTR Tracer concentration in the influent

10. Lee et al., Virtual E-Curve Method 10 Sensitivity analyses: Initial (theoretical) vs actual volume Numerical methods Integration step-size Sampling intervals Verification of Virtual E-Curve Method Tested various types of influent interferences with additional simulations: Recycle flows Continuous or Sudden influent concentration changes Varying influent flowrate

11. OUTLINE Introduction Virtual E-Curve Method Application to Full-Scale Tracer Study Summary and Conclusions

12. 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

13. Lee et al., Virtual E-Curve Method Sampling and Onsite Measurement 13

14. 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 Slug Load Tracer Input

15. Lee et al., Virtual E-Curve Method 15 Full Scale Test Results 0 50 100 150 200 250 300 0.00.51.01.52.02.53.03.54.0 Time (hours) Rhodamine WT (ppb) Anoxic Basin Influent (test result) Anoxic Basin Effluent (test result) Anoxic Basin Influent (theoretical) Anoxic Basin Effluent (theoretical)

16. Lee et al., Virtual E-Curve Method 16 Application of Virtual E-Curve Method to Test Results 44 min average (115% theoretical HRT) 2.5 CSTRs in series – NOT an ideal CSTR

17. Lee et al., Virtual E-Curve Method Virtual E-Curve Method Error Estimations with Uniform Tanks-in-Series Modeling 17

18. Lee et al., Virtual E-Curve Method Virtual E-Curve Method Error Adjustment with Non-Uniform Tanks-in-Series Modeling 18 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%) Center Rapidly Mixed Zone (50-75%) Tracer Injection Location

19. Lee et al., Virtual E-Curve Method Virtual E-Curve Method Error Adjustment with Non-Uniform Tanks-in-Series Modeling 19 91% theoretical HRT (reactor volume utilization) E Curve from Non-Uniform Tanks-in-Series Modeling Percent Error = 23%

20. OUTLINE Introduction Virtual E-Curve Method Application to Full-Scale Tracer Study Summary and Conclusions

21. Lee et al., Virtual E-Curve Method Summary and Conclusions 21 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.

22. Virtual E-Curve Method Questions? Don Lee, Ph.D., P.E. Senior Wastewater Process Engineer/Project Manager AECOM, Greenville SC 864-234-3583 don.lee02@aecom.com