Effectiveness of a Hydrodynamic Settling Device and a Stormwater Filtration Device in Milwaukee, Wisconsin Judy A. Horwatich, U.S. Geological Survey Roger T. Bannerman, Wisconsin Department of Natural Resources Robert Pearson, Wisconsin Department of Transportation Final Report No. 0092-00-03 September 2008 WISCONSIN DOT PUTTING RESEARCH TO WORK Wisconsin Department of Transportation Research, Development & Technology Transfer NOTICE: This research was funded by the Wisconsin Council on Research of the Wisconsin Department of Transportation and the Federal Highway Administration under Project #0092-00-03. The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views of the Wisconsin Department of Transportation or the Federal Highway Administration at the time of publication. This document is disseminated under the sponsorship of the Department of Transportation in the interest of information exchange. The United States Government assumes no liability for its contents or use thereof. This report does not constitute a standard, specification or regulation. The United States Government does not endorse products or manufacturers. Trade and manufacturers' names appear in this report only because they are considered essential to the object of the document. Technical Report Documentation Page 1. Report No. 0092-00-03 2. Government Accession No 3. Recipient’s Catalog No 4. Title and Subtitle 5. Report Date Effectiveness of a Hydrodynamic Settling Device and a Stormwater Filtration Device in Milwaukee, Wisconsin 6. Performing Organization Code 7. Authors 8. Performing Organization Report No. Judy A. Horwatich, Roger T. Bannerman, Robert Pearson 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) U.S. Department of Interior U.S. Geological Survey 11. Contract or Grant No. 8508 Research Way Middleton, WI 53562 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Wisconsin Department of Transportation Final Report Division of Business Management August, 2000 –June, 2008 Bureau of Business Services 14. Sponsoring Agency Code Research & Communications Section P.O. Box 7957 Madison, WI. 53707-7957 15. Supplementary Notes 16. Abstract The treatment efficiency of two proprietary stormwater treatment devices was tested at a freeway site in an ultra-urban part of Milwaukee, Wis. One treatment device is categorized as a hydrodynamic settling device (HSD) that removes pollutants by sedimentation and flotation. The other treatment device is categorized as a stormwater filtration device (SFD) that removes pollutants by filtration and sedimentation. During runoff events, flow measurements were recorded and water-quality samples were collected at the inlet and outlet of each device. An efficiency ratio and summation of loads (SOL) calculation were used to estimate the treatment efficiency of each device. Most constituents showed a reduction in average concentration and total load leaving the device, but a few constituents, especially dissolved ones, showed an increase in concentration and load at the outlets. The efficiency ratios for the HSD tend to be higher than the SOLs. In contrast the efficiency ratios and SOLs are about the same for the SFD. 17. 18. Distribution Statement Hydrodynamic settling device, Stormwater filtration device, Efficiency ratio, Summation of load, Treatment No restriction. This document is available to the public efficiency, Total suspended solids, Suspended sediment, through the National Technical Information Service Flow rate 5285 Port Royal Road Springfield VA 22161 18. Security Classif.(of this report) 19. Security Classif. (of this page) 20. No. of Pages 21. Price Unclassified Unclassified 122 Form DOT F 1700.7 (8-72) Reproduction of completed page authorized ii Contents Abstract 9 Introduction 11 Purpose and Scope ................................................................................................................ 14 Site Description..................................................................................................................... 14 Hydrodynamic Settling Device.................................................................................... 16 Stormwater Filtration Device....................................................................................... 17 Design of the Hydrodynamic Settling Device and Stormwater Filtration Device 17 Hydrodynamic Settling Device.................................................................................... 18 Stormwater Filtration Device....................................................................................... 19 Sampling Methods 21 Measurement of Rainfall Depths .......................................................................................... 21 Flow Monitoring Methods .................................................................................................... 22 Calibration of Flow ...................................................................................................... 22 Water-Quality Sampling ....................................................................................................... 26 Particle-Size Analysis .................................................................................................. 27 Monitoring Complications .................................................................................................... 29 Quality Control ..................................................................................................................... 31 Hydrodynamic Settling Device.................................................................................... 32 Stormwater Filtration Device....................................................................................... 33 Evaluation of Settling and Filtration Treatment Devices 33 Rainfall Data ......................................................................................................................... 34 Number of Rainfall Events with Water-Quality Data........................................................... 37 Flow Data.............................................................................................................................. 38 Particle-Size Distribution...................................................................................................... 42 Particle-Size Distributions for the Hydrodynamic Settling Device ............................. 43 Particle-Size Distributions for the Stormwater Filtration Device................................ 46 iii Summary of Inlet and Outlet Chemical Concentrations ....................................................... 49 Efficiency Calculations ......................................................................................................... 55 Efficiency Ratio .................................................................................................................... 56 Efficiency Ratio for the Hydrodynamic Settling Device ............................................. 57 Efficiency Ratio for the Stormwater Filtration Device................................................ 60 Summation of Loads ............................................................................................................. 63 Summation of Loads for Hydrodynamic Settling Device............................................ 64 Summation of Loads for the Stormwater Filtration Device......................................... 66 Total Suspended Solids Reductions in Other Field Tests of the Hydrodynamic Settling Device and Stormwater Filtration Device................................................................................................ 68 Other Field Verification Studies for the Hydrodynamic Settling Device.................... 68 Field Verification Studies for the Stormwater Filter Device ....................................... 71 Mass Balance of Sediment Retained in the Devices............................................................. 73 Mass Balance for Hydrodynamic Settling Device....................................................... 76 Mass Balance for the Stormwater Filtration Device.................................................... 78 Summary and Conclusions 79 Acknowledgments................................................................................................................. 84 References 85 Appendix 1 (previous studies) 92 Appendix 2 Hydrodynamic Settling Device 95 Appendix 3 Stormwater filtration device 107 iv Figures Figure 1. Location of monitored sites for the hydrodynamic settling device and stormwater filtration device in the City of Milwaukee, Wis................................................................................................16 Figure 2. Piping system from freeway to hydrodynamic settling device. ......................................17 Figure 3. Diagram of hydrodynamic settling device (U.S. Environmental Protection Agency, 2005). ...........................................................................................................................................19 Figure 4. Overview of the stormwater filtration device (U.S. Environmental Protection Agency 2004, b). .......................................................................................................................................20 Figure 8. Rain gage for both devices. ..........................................................................................22