Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
N A T I O N A L C O O P E R A T I V E H I G H W A Y R E S E A R C H P R O G R A M NCHRP REPORT 767 Measuring and Removing Dissolved Metals from Stormwater in Highly Urbanized Areas Michael Barrett Lynn Katz Department of Civil, arChiteCtural, anD environmental engineering University of texas at aUstin Austin, TX Scott Taylor rBf Consulting Carlsbad, CA John Sansalone Department of environmental engineering sCienCes University of florida Gainesville, FL Marty Stevenson KinnetiC laBoratories, inC. Lahaina, HI Subscriber Categories Highways â¢ Environment â¢ Hydraulics and Hydrology TRANSPORTAT ION RESEARCH BOARD WASHINGTON, D.C. 2014 www.TRB.org Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration
NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed research provides the most effective approach to the solution of many problems facing highway administrators and engineers. Often, highway problems are of local interest and can best be studied by highway departments individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation develops increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of cooperative research. In recognition of these needs, the highway administrators of the American Association of State Highway and Transportation Officials initiated in 1962 an objective national highway research program employing modern scientific techniques. This program is supported on a continuing basis by funds from participating member states of the Association and it receives the full cooperation and support of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board of the National Academies was requested by the Association to administer the research program because of the Boardâs recognized objectivity and understanding of modern research practices. The Board is uniquely suited for this purpose as it maintains an extensive committee structure from which authorities on any highway transportation subject may be drawn; it possesses avenues of communications and cooperation with federal, state and local governmental agencies, universities, and industry; its relationship to the National Research Council is an insurance of objectivity; it maintains a full-time research correlation staff of specialists in highway transportation matters to bring the findings of research directly to those who are in a position to use them. The program is developed on the basis of research needs identified by chief administrators of the highway and transportation departments and by committees of AASHTO. Each year, specific areas of research needs to be included in the program are proposed to the National Research Council and the Board by the American Association of State Highway and Transportation Officials. Research projects to fulfill these needs are defined by the Board, and qualified research agencies are selected from those that have submitted proposals. Administration and surveillance of research contracts are the responsibilities of the National Research Council and the Transportation Research Board. The needs for highway research are many, and the National Cooperative Highway Research Program can make significant contributions to the solution of highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement rather than to substitute for or duplicate other highway research programs. Published reports of the NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM are available from: Transportation Research Board Business Office 500 Fifth Street, NW Washington, DC 20001 and can be ordered through the Internet at: http://www.national-academies.org/trb/bookstore Printed in the United States of America NCHRP REPORT 767 Project 25-32 ISSN 0077-5614 ISBN 978-0-309-28391-5 Library of Congress Control Number 2014935034 Â© 2014 National Academy of Sciences. All rights reserved. COPYRIGHT INFORMATION Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein. Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, FAA, FHWA, FMCSA, FTA, or Transit Development Corporation endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP. NOTICE The project that is the subject of this report was a part of the National Cooperative Highway Research Program, conducted by the Transportation Research Board with the approval of the Governing Board of the National Research Council. The members of the technical panel selected to monitor this project and to review this report were chosen for their special competencies and with regard for appropriate balance. The report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the Governing Board of the National Research Council. The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board, the National Research Council, or the program sponsors. The Transportation Research Board of the National Academies, the National Research Council, and the sponsors of the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade or manufacturersâ names appear herein solely because they are considered essential to the object of the report.
The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. On the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Ralph J. Cicerone is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. C. D. Mote, Jr., is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, on its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academyâs purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. C. D. Mote, Jr., are chair and vice chair, respectively, of the National Research Council. The Transportation Research Board is one of six major divisions of the National Research Council. The mission of the Transporta- tion Research Board is to provide leadership in transportation innovation and progress through research and information exchange, conducted within a setting that is objective, interdisciplinary, and multimodal. The Boardâs varied activities annually engage about 7,000 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. The program is supported by state transportation departments, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individu- als interested in the development of transportation. www.TRB.org www.national-academies.org
C O O P E R A T I V E R E S E A R C H P R O G R A M S AUTHOR ACKNOWLEDGMENTS This study was conducted with funding provided through the National Cooperative Highway Research Program (NCHRP) Project 25-32, Measuring and Removing Dissolved Metals from Stormwater in Highly Urbanized Areas. The NCHRP is supported by annual voluntary contributions from the state Depart- ments of Transportation. This project was prepared by Dr. Michael Barrett and Dr. Lynn Katz, University of Texas at Austin; Scott Taylor, RBF Consulting; Dr. John Sansalone, University of Florida; and Marty Stevenson, Kinnetic Laboratories, Inc. CRP STAFF FOR NCHRP REPORT 767 Christopher W. Jenks, Director, Cooperative Research Programs Christopher Hedges, Manager, National Cooperative Highway Research Program Danna Powell, Senior Program Assistant Eileen P. Delaney, Director of Publications Margaret B. Hagood, Editor NCHRP PROJECT 25-32 PANEL Field of Transportation PlanningâArea of Impact Analysis William Fletcher, Oregon DOT, Salem, OR (Chair) Gregory E. Granato, U.S. Geological Survey, Northborough, MA G. Scott McGowen, California DOT, Sacramento, CA Le Chi Nguyen, Washington State DOT, Seattle, WA Judy A. Ruszkowski, Earl Engineering Services, Lyons, MI John C. Taylor, Mississippi DOT, Jackson, MS Christopher I. Thornton, Colorado State University, Fort Collins, CO Patricia A. Cazenas, FHWA Liaison Stephen F. Maher, TRB Liaison
F O R E W O R D By Christopher Hedges Staff Officer Transportation Research Board This NCHRP report presents prototype best management practices (BMPs) for the removal of dissolved metals in stormwater runoff. Three conceptual configurations are presented in detail: two vault system configurations for urban and rural settings, and an inlet scupper with media for bridge deck drainage systems. The report also includes standard protocols to accurately measure the levels of dissolved metals in stormwater. Practical guidance on the use of these protocols is provided in an appendix to the final report. The report is accompanied by an Excel spreadsheet on CD designed to assist in sizing the filter bed in the vaults and the bridge deck inlet scupper. The report is suitable for immediate application by transportation practitioners in plan- ning, design, and construction, particularly in areas where receiving waters are most sus- ceptible to the impacts of dissolved metals. Starting in the late 1980s, efforts to address polluted stormwater runoff have increased significantly, and the requirements for treating the runoff have gotten more stringent. Not long ago, most highway runoff could be treated using a few simple treatment methods such as bioswales, wet ponds, or vegetated filter strips. More recently however, the treatment requirements have been shifting to include the removal of dissolved metals. Dissolved met- als in stormwater are becoming more of a concern to regulatory agencies, particularly in highly urbanized areas where land values and lack of available space limit the treatment options. Furthermore, there are concerns about the current methods used to determine dissolved metal content. There is evidence that the measurements obtained can vary widely from the effects of a number of factors, including the measurement method and testing protocols, the testing equipment used, methods of cleaning the test equipment, and the scheduling of sampling times during storm events. Under NCHRP Project 25-32, a research team led by the University of Texas at Austin studied the environmental chemistry of metals in highway runoff, reviewed key proper- ties that control the chemical speciation of metals within water, and identified processes and parameters that affect the rate and extent of removal of metal ions from particulate matter. Based on the results, the team developed conceptual configurations for three design scenarios: highly urbanized areas, more rural locations with vegetated shoulders or embankments, and bridges. For each configuration, the design engineer is provided with guidance on integrat- ing them with both new and existing drainage systems. Each configuration involves pre- treatment of runoff, pH buffering, physical retention of the media, hydraulic design, and system maintenance.
C O N T E N T S 1 Chapter 1 Introduction 1 1.1 Background 1 1.2 Research Approach 1 1.2.1 Phase I 2 1.2.2 Phase II 3 1.3 Report Structure 4 Chapter 2 Characterization of Highway Runoff 4 2.1 Stormwater Composition 6 2.2 Particles in Highway Runoff 7 2.3 Metal Partitioning and Complexation in Highway Runoff 10 2.4 Summary 11 Chapter 3 Environmental Chemistry of Metals in Surface Waters 11 3.1 Introduction 11 3.1.1 Metal Speciation 11 3.1.2 Natural Water Composition 13 3.1.3 Characterization of Natural Organic Matter in Receiving Waters 17 3.1.4 Summary 18 3.2 Metal Ion Speciation in Solution: Complexation Reactions 18 3.2.1 Complexation with Inorganic Ligands 22 3.2.2 Complexation in the Presence of Chelating Agents 22 3.2.3 Complexation by Humic Substances 24 3.2.4 Modeling Metal Complexation 26 3.2.5 Summary 26 3.3 Oxidation/Reduction Processes 29 3.3.1 Summary 29 3.4 Precipitation Processes 31 3.4.1 Summary 31 3.5 Sorption Processes 31 3.5.1 Charge Development in Clays and Clay Minerals 33 3.5.2 Surface Complexation 36 3.5.3 Surface Complexation Models 40 3.5.4 Summary 40 3.6 Bioavailability and the Biotic Ligand Model 42 3.6.1 Summary 42 3.7 Conclusions 45 Chapter 4 Treatment of Metals in Highway Runoff 45 4.1 Infiltration 46 4.2 Adsorption 51 4.3 Recommendation for Media Selections
52 Chapter 5 Laboratory Testing and Modeling Methods 52 5.1 Introduction 52 5.2 Development of the Laboratory Testing Protocol 52 5.2.1 Important Factors Affecting Laboratory Evaluation of Metal Adsorption 56 5.3 Development of a Synthetic Runoff Cocktail 56 5.3.1 Collection and Preparation of Highway Runoff Organic Matter 59 5.3.2 Composition of the Inorganic Constituents in the Synthetic Runoff 60 5.3.3 Media Selection and Preparation 61 5.4 Batch Reactor Studies 62 5.5 Experimental Column System 65 5.6 Experimental Results 65 5.6.1 Batch Reactor Studies of Cu Adsorption Capacity and Equilibration Times 66 5.6.2 Column Protocol Verification 66 5.6.3 Contrasting Performance of Different Media and Different Metal Ions 69 5.6.4 Impact of Highway Organic Matter 71 5.6.5 Effects of pH and Ionic Strength on Cu(II) and Zn(II) Sorption 72 5.6.6 Evaluation of pH Stabilizing Media 74 5.6.7 Experiments Conducted at pH Representative of Stormwater 76 5.6.8 Experiments Conducted with Real Stormwater 78 5.6.9 Experiments Conducted at Alkalinity Representative of Stormwater 81 5.7 Application of Results for Field Scale Design 83 Chapter 6 Conceptual BMP Designs 83 6.1 Basis of BMP Design Concepts 84 6.1.1 Site-Specific Constraints and Design Considerations 87 6.1.2 Design Procedure 88 6.1.3 Description of Construction Details of Preferred Concept Alternatives 90 Chapter 7 Recommendations for Future Work 90 7.1 Introduction 90 7.2 Field Testing of GFO Conceptual BMPs 90 7.3 Additional Characterization of Highway Runoff 90 7.4 Incorporation of GFO in the PFC 91 7.5 Incorporation of GFO in Filtration Systems 92 Chapter 8 Summary and Conclusions 92 8.1 Introduction 92 8.2 Characterization of Highway Runoff 92 8.3 Environmental Chemistry of Metals in Natural Waters 93 8.4 Previous Studies of the Treatment of Dissolved Metals 94 8.5 Laboratory Evaluation of Dissolved Metals Removal 95 8.6 Stormwater Treatment Conceptual Designs 96 8.7 Recommendations for Future Research 97 Bibliography
A-1 Appendix A Practical Guidance for Measurement of Dissolved Metals in Stormwater Runoff B-1 Appendix B Detailed Cleaning Protocol for Equipment to be used for Collection of Stormwater Samples for Measurement of Dissolved Metals Note: Many of the photographs, figures, and tables in this report have been converted from color to grayscale for printing. The electronic version of the report (posted on the Web at www.trb.org) retains the color versions.