Emily Matlock, Garey Fox, Deb Sahoo, and Jorge Guzman

1. Emily Matlock, Garey Fox, Deb Sahoo, and Jorge Guzman 2009-2010 Oklahoma State University Woolpert Scholar Quantifying the Effectiveness of Vegetative filter Strips in Removing E. coli from Runoff: A Laboratory Scale Study

2. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Outline • Background • Experiment Design • Sampling Methods • Results • Conclusion

3. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar E. coli • Bacteria found in feces • Agricultural and urban problem • Outbreaks • August 2008: Locust Grove, OK • May 2009: Oklahoma River • April 2010: Canon City, CO http://www.shardcore.org/shardpress/index.php/2006/01/19/e-coli-2006/trackback/

4. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Vegetative Filter Strips • A strip or area of herbaceous vegetation that removes contaminants from overland flow. (Natural Resources Conservation Service; code 393) • Best Management Practice (BMP) • Current Standards: Length based

5. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Previous Studies (VFS w/ bacteria)

6. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Hypothesis The hydrologic/hydraulic conditions of VFS determine the effectiveness of removing E. coli from runoff water Approach Large-scale laboratory soil box

7. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Laboratory Scale Soil Box • 100 cm x 200 cm • Sides: 70 cm • 6% slope • Inflow & Collection Trays 100 cm 200 cm

8. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Soil Properties & Packing • Sandy Loam (66% sand, 28% silt, 6% clay) • Packed 1.5 g/cm3 • 5-7 layers at 10 cm • Surface leveled • Saturated hydraulic conductivity (Ks): 1.0 cm/hr (double-ring infiltrometer test, 2 reps)

9. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Experimental Techniques • VFS effectiveness tested for different flow conditions • Liquid Swine Manure – E. coli http://records.goldenagecartoons.com/rare/porky.bmp

10. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Experimental Conditions • Diluted Manure Runon • 3 Bare Soil • Full Width (100 cm) • Qin = 20, 52, 116 cm3/s • 7 Vegetation (Rye grass, 8-10 cm) • 3 Full Width (100 cm) • Qin = 25, 36, 95 cm3/s • 4 Concentrated Flows (40 cm) • Qin = 43, 45, 85, 117 cm3/s • Clean Water Runon • Similar flow conditions 100 cm 40 cm 40 cm

11. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Quantifying Inflow & Outflow • Inflow - Mariotte infiltrometer • Outflow - collection bucket • Data from scales (5 s): quantify flow rate

12. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Runon Water • For diluted manure runon, Mariotte infiltrometer contained: • 25 kg tap water (prefilled) • 200 g soil • 90 mL of swine effluent • For clean water runon, Mariotte infiltrometer contained: • 25 kg tap water (prefilled) • 200 g soil • Inflow reservoir contained tap water and soil

13. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Sampling • Sample collected from Mariotte bottle - Co • Mariotte infiltrometer nozzle opened • Samples collected from outflow • Inflow reservoir (runon) sample collected – Co

14. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Sampling • 100 mL IDEXX bottles • Pre-weighed • 60-100 mL runoff water collected • Initial outflow sample • Sampling interval: • Manure runon experiment • Rising limb: 20-30 s • After peak: 90-120 s • Clean water runon experiment • 45 s throughout • 10 - 25 samples acquired for every run

15. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar E. coli Concentration • IDEXX’s semi-automated Quanti-Tray • Sealed • Incubated • 35˚C (95˚F) • 24 hours • MPN (most probable number)/100 mL • # of florescent wells

16. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Results • Bare Soil: Channelized Flow • Vegetation: Uniform Sheet Flow

17. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Results Typical Flow and E. coli Response • Inflow vs. Outflow • Infiltration • Concentration increase

18. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Results Typical Flow and E. coli Response • Inflow vs. Outflow • Infiltration • Concentration decrease

19. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Results Wide vs. Concentrated Flow (Vegetated) • Eventually • C = Co • Surface Area

20. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Results E. Coli Mass Reduction vs. Inflow Rate • Slight trend • High P-value

21. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Results E. Coli Mass Reduction vs. Inflow Rate • Slight negative correlation • R2 is low • Unable to predict VFS efficiency

22. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Results E. Coli Mass Reduction vs. Outflow Rate • Stronger negative correlation • R2 is moderate • Not definitive enough to predict VFS efficiency

23. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Results E. Coli Mass Reduction vs. Infiltration • Strong positive correlation • R2 is very high • Infiltration affects E. coli mass reduction

24. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Results E. Coli Mass Reduction vs. Width • Lower P-value • Flow width controls infiltration area

25. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Results E. Coli Concentrations after Clean Water Runon • Concentration amounts negligible

26. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Results E. Coli concentrations in soil • Higher concentrations in deeper soil • Supports infiltration

27. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Conclusion

28. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Conclusion • Infiltration is the best way to predict the efficiency of VFS in the removal of E. coli • The greater the area of flow, the higher the E. coli Mass Reduction • No reduction in E. coli concentrations • The inflow rate has only a slight affect on the VFS effectiveness • Minimal E. coli were measured in clean water runon experiments two days after diluted manure runon Future Work • Thicker vegetation • Thatch layer

29. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Acknowledgements • This project could not be completed without the financial support of Woolpert, Inc.

30. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Quantifying the Effectiveness of Vegetative filter Strips in Removing E. coli from Runoff: A Laboratory Scale Study • Questions?

31. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Dilution Bottles • Diluted Manure Runon • 90 mL distilled water • 10 mL sample • E. coli Reagent • DF = 10 • Clean water runon • 100 mL sample • E. coli Reagent • DF = 1

32. E. coli Removal by VFS Oklahoma State University/Woolpert Scholar Methods & Materials • Sediment sample • Outflow bucket • Total Sediment Concentration