Physicochemical Treatment of Hazardous Wastes WALTER Z TANG CRC PR E S S Boca Raton London New York Washington, D.C TX69272_C00.fm Page Wednesday, November 19, 2003 1:21 PM Library of Congress Cataloging-in-Publication Data Tang, Walter Z Physicochemical treatment of hazardous wastes / Walter Z Tang p cm Includes bibliographical references and index ISBN 1-56676-927-2 (alk paper) Hazardous wastes—Purification I Title TD1060.T35 2003 628.4′2—dc21 2003055435 This book contains information obtained from authentic and highly regarded sources Reprinted material is quoted with permission, and sources are indicated A wide variety of references are listed Reasonable efforts have been made to publish reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials or for the consequences of their use Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage or retrieval system, without prior permission in writing from the publisher The consent of CRC Press LLC does not extend to copying for general distribution, for promotion, for creating new works, or for resale Specific permission must be obtained in writing from CRC Press LLC for such copying Direct all inquiries to CRC Press LLC, 2000 N.W Corporate Blvd., Boca Raton, Florida 33431 Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation, without intent to infringe Visit the CRC Press Web site at www.crcpress.com © 2004 by CRC Press LLC Lewis Publishers is an imprint of CRC Press LLC No claim to original U.S Government works International Standard Book Number 1-56676-927-2 Library of Congress Card Number 2003055435 Printed in the United States of America Printed on acid-free paper © 2004 by CRC Press LLC TX69272_C00.fm Page Wednesday, November 19, 2003 1:21 PM Dedication In memory of my father, Yuxiang Tang To my mother, Yongcui Hu, and To my children, William and Elizabeth, with love © 2004 by CRC Press LLC TX69272_C00.fm Page Wednesday, November 19, 2003 1:21 PM Preface On average, one ton of hazardous waste per person is generated annually by industries in the United States Before the Resource Conservation and Recovery Act of 1984, hazardous wastes were improperly disposed of into the environment without any regulation As a result, remediation of these contaminated sites and management of the ongoing hazardous waste sources are two major tasks to be achieved by treatment technologies Due to the complex nature of the contaminated media and of the pollutants, environmental professionals are facing a host of questions, such as: What are the contaminated media? What is the nature of the pollutants? What are the concentrations of each pollutant? Among biological, physicochemical, or thermal technologies, if physicochemical processes are to be the solution, the treatability of various pollutants must be assessed before a process can be properly designed This book systematically examines the treatability of hazardous wastes by various physicochemical treatment processes according to the Quantitative Structure–Activity Relationships (QSARs) between kinetic rate constants and molecular descriptors I have attempted to achieve five major goals in this book: (1) fundamental theories of thermokinetics such as the transition state theory are used to integrate research findings in Advanced Oxidation Process (AOP) research; (2) reaction kinetics and mechanisms for each AOP are explained in terms of elementary reactions and the reactive center; (3) QSARs are introduced as methodologies to assess the treatability of organic compounds; (4) computational molecular descriptors such as the EHOMO and ELUMO are used extensively in the QSAR analysis; (5) the kinetics of various AOPs are compared so that the most effective process can be selected for a given class of organic pollutants This book is divided into five parts Chapter to Chapter define the hazardous waste problems and physicochemical approaches to solve these problems Chapter explains QSAR theory and its application to predicting molecular descriptors and hydroxyl radical reactions Chapter to Chapter 12 focus on each of the eight most important AOPs Chapter 13 presents a major reductive treatment technology, zero-valence iron, and Chapter 14 compares each AOP according to its oxidation kinetics for specific classes of organic compounds Each chapter begins with an introduction of the process and its historical development The intention is to demonstrate how fundamental sciences guide the search for these innovative technologies Also, such introductions provide the information necessary for readers to delve into the literature for current research topics Then, the principles of the process and the degradation kinetics, along with mechanisms of organic © 2004 by CRC Press LLC TX69272_C00.fm Page Wednesday, November 19, 2003 1:21 PM pollutants are explained in terms of elementary reactions These elementary reactions not only are important in assessing the treatability of organic pollutants using QSAR but are also critical in properly designing AOP processes Finally, QSAR models are discussed to demonstrate the effect of molecular structure on their degradation kinetics and to rank the treatability of each organic compound This book is intended for graduates, engineers, and scientists affiliated with universities, consulting firms, or national laboratories and who are dealing with the remediation of hazardous wastes in water, groundwater, and industrial wastewater Due to the in-depth discussion of organic chemistry, graduate students in environmental engineering and upper-level undergraduates in chemistry, chemical engineering, or environmental sciences who intend to enter environmental engineering should find it useful in their professional development Students will learn a systematic approach to applying various sciences to the search for effective treatment technologies in terms of thermokinetic principles Engineers will find the QSAR models extremely useful in selecting treatment processes for hazardous wastes according to the molecular structures of organic pollutants Scientists in industrial and governmental laboratories, as well as designers and reviewers in remediation projects, will also find the book helpful in their efforts to restore our environment and keep it clean During the 1970s, the U.S Environmental Protection Agency designated phase-transfer technologies such as air stripping and activated carbon adsorption as the best available technologies The search for mineralizing organic pollutants shifted the focus from phase-transfer technologies to oxidative technologies after the Hazardous Waste Amendment in 1984 As a result, AOPs were developed in laboratories, extended to pilot sites, and finally applied in the field from the 1980s to the present The concept of an AOP includes any process that uses hydroxyl radicals as the predominant species; however, the concept failed to provide fundamental theories such as transition state theory to guide research communities in their search for the most effective oxidation processes In a strict sense, then, AOP should be defined as a Catalytic Oxidation Process (COP), which would provide sound scientific footing for the search for innovative technologies It is well documented that oxidants such as oxygen, ozone, and hydrogen peroxide oxidize organic pollutants slowly It is only when they are catalytically decomposed into other active species such as hydroxyl radicals that the activation barrier of the activated complex can be significantly lowered The catalysts normally used are ultraviolet photons, transition metals or their ions, ultrasound, and electrons Increasing temperature and pressure can further enhance the catalytic effect My research on AOPs began over 12 years ago at the University of Delaware When I worked on the degradation of phenols by a visible photon/ CdS system, I had to wake up at midnight in order to take samples from a photocatalytic reactor because the reaction half time in degrading 0.001-M phenol is about day After I found that Fenton’s reagent was an extremely © 2004 by CRC Press LLC TX69272_C00.fm Page Wednesday, November 19, 2003 1:21 PM fast process, I added hydrogen peroxide and ferrous ion separately to the reactor The reaction half time reduced from one day to a few hours When I added hydrogen peroxide first and then the ferrous sulfate, the reaction half time was reduced to a few minutes It became clear to me during my investigation of the oxidation kinetics and mechanisms of chlorinated phenols by Fenton’s reagent that the efficiency of AOPs depends upon both the rate and the amount of hydroxyl radical generated and the molecular structure of organic compounds It has long been recognized that the treatability of different classes of organic compounds differs significantly Furthermore, the treatability of chlorinated compounds within a given class of organic pollutants decreases as the chlorine content in a molecule increases Indeed, the carbon in tetrachloride has been oxidized by chlorine so much that it is even insensitive to hydroxyl radical attack Therefore, elementary iron may be a more economical way to reduce these pollutants rather than to oxidize them To quantify the effect of chlorine, QSAR models are used to assess the effect of chlorine on molecular descriptors such as EHOMO and ELUMO The treatability of organic compounds by each AOP, then, can be evaluated using QSAR models of the oxidation kinetic rate constants and molecular descriptors Thermokinetics, group theory, and computational QSARs should find broad application in future research effort on AOPs for several reasons: (1) thermokinetics bridges thermodynamics and kinetics, which serve as the foundation for QSAR analysis; (2) group theory may offer kinetic calculations of activated complex for a given class of compounds, and the resulting degradation rate constants can be more accurately estimated; and (3) as more data regarding operational costs become available for each technology, QSARs may be incorporated into the calculations to estimate the operational cost of a specific compound In addition, nanotechnology will become another research focus in the next decade to develop nanoparticles such as elementary iron, TiO2, nanofiltration, and electromembranes in the physicochemical treatment of hazardous wastes © 2004 by CRC Press LLC TX69272_C00.fm Page Wednesday, November 19, 2003 1:21 PM About the Author Walter Z Tang (B.S., Sanitary Engineering, Chongqing University, Chongqing, China, 1983; M.S., Environmental Engineering, Tsinghua University, Beijing, China, 1986; M.S., Environmental Engineering, University of Missouri-Rolla, 1988; Ph.D., Environmental Engineering, University of Delaware, 1993) is an Associate Professor and Graduate Director for Environmental Engineering in the Department of Civil and Environmental Engineering at Florida International University (FIU), Miami, FL He has been a registered Professional Engineer in Florida since 1993 Dr Tang has had extensive research experience over the past 14 years in the area of physicochemical treatment processes; environmental applications of aquatic, organic, catalytic, and colloidal chemistry; advanced oxidation processes; environmental molecular structure–activity relationships (QSARs); and methodology in environmental impact assessment Dr Tang is the principal investigator for 14 research projects supported by the U.S Environmental Protection Agency, the National Institutes of Health, and the National Science Foundation He has published 24 peer-reviewed papers and 41 conference papers, co-authored one book, and contributed one chapter to a book Also, he has written graduate teaching manuals for three different graduate courses He has been a referee for 12 journals and has served as a proposal reviewer for the NSF and the National Research Council Dr Tang has organized and presided over 11 sessions at various national and international conferences on advanced oxidation processes (AOPs) and was the invited speaker at Florida Atlantic University in 2001 Dr Tang has supervised three post doctors, three visiting professors, and 35 graduate students in environmental engineering, and he has taught six undergraduate courses and nine graduate courses in the Department of Civil and Environmental Engineering at FIU Dr Tang received FIU’s Faculty Research Award in 1997, Faculty Teaching Award in 1998, and Departmental Teacher of the Year Award in 1998 He is a member of Chi Epsilon and is listed in Who’s Who in the World, Who’s Who in America, Who’s Who in Science and Engineering, and Who’s Who Among America’s Teachers Since 1994, Dr Tang has been a co-principal investigator in joint research projects on AOPs with professors at Tsinghua University, Chongqing University, and the Third Medical University of Chinese Military in Chongqing, China As a research fellow in the China–Cornell Fellowship Program © 2004 by CRC Press LLC TX69272_C00.fm Page 10 Wednesday, November 19, 2003 1:21 PM supported by the Rockefeller Foundation, Dr Tang offered six seminars at Tsinghua University As a co-principal investigator from 1998 to 2002 of the Two-Bases Program sponsored by the China National Science Foundation, he advised a Ph.D student at Tsinghua University on his dissertation: QSARs in the Anaerobic Degradability of Organic Pollutants Chongqing University and Chongqing Jianzhu University granted the visiting professorship to Dr Tang in 1999 He won six joint research projects sponsored by the Chinese Ministry of Education for Chongqing University He was the invited speaker at Nankai University and Gansu Industry University in 2002 and at Wuhan University in 2003 He was named the Outstanding Chinese Scholar in the southern region of the United States and served as a Foreign Expert in the State Sunshine Program of China The Chinese Ministry of Education invited Dr Tang to Beijing as a state guest for the 50th anniversary of China National Day in 1999 © 2004 by CRC Press LLC TX69272_C00.fm Page 11 Wednesday, November 19, 2003 1:21 PM Acknowledgments I would like to acknowledge the contributions to this book made by my former graduate students: Tzai-Shian Jung, Angela Pierotti, Sangeeta Dulashia, Todd Hendrix, Ricardo Martinez, Lucero Vaca, Stephanie Tassos, Rena Chen, Taweeporn Fongtong, Jiun-Jia Hsu, Kenneth Morris, Jose Polar, Carlos Hernandez, and Jeffrey Czajkowski I thank Jiashun Huang, Dennis Maddox, and Pia Hansson Nunoo for their many hours devoted to typing and drawing of the figures I would like to thank all the students since 1991 at Florida International University (FIU) who took the graduate course, Advanced Treatment System, upon which the book is based Students who assisted in this book include Bernine Khan, Lillian Costa-Mayoral, Christopher Wilson, and Oscar Carmona A special acknowledgment goes to Georgio Tachiev of the Hemisphere Center for Environmental Technology at FIU for his constructive proofreading I am grateful to Dr C.P Huang at the University of Delaware for introducing me to the research of AOPs Many QSAR models were developed through financial support from the U.S Environmental Protection Agency, National Science Foundation, and National Institutes of Health, and their support is greatly appreciated Thanks go to Mrs Virginia Broadway at the USEPA for supporting and administrating five EPA fellowships to my students over the last decade Dr William Cooper and his colleagues are acknowledged for their work on high-energy electron beams I would like to thank Dean Vish Prasad and Associate Dean David Shen of the College of Engineering at FIU for allowing me to complete the book I am in debt to Gail Renard and Sara Kreisman, my book editors at CRC Press LLC, who provided excellent professional guidance and spent numerous days editing and proofreading the manuscript © 2004 by CRC Press LLC TX69272_bookTOC.fm Page 13 Thursday, November 20, 2003 10:55 AM Table of Contents Chapter Environmental Laws 1.1 1.2 Introduction Environmental Laws 1.2.1 National Environmental Policy Act (NEPA) 1.2.2 Occupational Safety and Health Act (OSHA) 1.2.3 Clean Water Act (CWA) 1.2.4 Safe Drinking Water Act (SDWA) 1.2.5 Toxic Substances Control Act (TSCA) 1.2.6 Resource Conservation and Recovery Act (RCRA) 1.2.7 Hazardous and Solid Waste Amendments (HSWA) 1.2.7.1 Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) 1.2.7.2 Superfund Amendments Reauthorization Act (SARA) 1.2.7.3 Clean Air Act (CAA) 1.3 Summary References Chapter Environmental Hazardous Wastes 2.1 2.2 2.3 2.4 2.5 Introduction Classification of Hazardous Pollutants Sources of Hazardous Waste Contaminated Media of Hazardous Wastes 2.4.1 Groundwater 2.4.2 Soil 2.4.3 Air 2.4.4 Sludge and Sediments Distribution of Hazardous Pollutants in Contaminated Sites 2.5.1 National Priorities List Sites 2.5.1.1 Contaminants 2.5.2 Resource Conservation and Recovery Act 2.5.2.1 Contaminated Media 2.5.2.2 Contaminants 2.5.3 Underground Storage Tanks Sites 2.5.3.1 Contaminated Media 2.5.3.2 Contaminants 2.5.4 Department of Defense 2.5.4.1 Contaminated Media © 2004 by CRC Press LLC TX69272_C14.fm Page 555 Friday, November 14, 2003 2:13 PM Combinations of Advanced Oxidation Processes TOC kuv280 kd 16 14 12 10 16 14 12 10 0 170 680 kd and kuv280 (1/min) rid (1/m*min) and TOC (%) rid 555 1360 H2O2 Dose (mg/L) FIGURE 14.20 TOC remaining as a function of the initial concentration of H2O2 Reaction pH = 7.0; treatment time = hr (From Alaton, I.A et al., Water Res., 36, 1143–1154, 2002 With permission.) TABLE 14.16 Effect of pH on the UV/TiO2: Treatment of Simulated Reactive Dyebath Effluent (TiO2 dose = 1000 mg/L) Reaction pH 3.0 7.0 9.0 11.0 k UV280 kd (1/min) rid (1/m.min) (1/min) 0.04 0.05 0.04 0.02 0.24 0.31 0.28 0.15 0.02 0.02 0.02 0.01 TOC Removal (%) 12.5 10.3 9.0 0.0 Source: Alaton, I.A et al., Water Res., 36, 1143–1154, 2002 With permission 14.4.5 1,3,5-Trichlorobenzene (TCB) and Pentanoic Acid (PA) TCB is widely present in the chemical industry as a by-product of pesticide manufacturing (Masten et al., 1996) Pentanoic acid was used as an •OH radical probe due to its low reactivity with molecular ozone and high reactivity with hydroxyl radicals generated from the decomposition of ozone pH, humic acid, and bicarbonate may impact the efficiency of oxidation of TCB and PA Natural water was simulated by adding humic substances or bicarbonate to deionized water The degradation rate was assumed to be first order with respect to the concentration of the target chemicals by using a continuous-flow, stirred-tank reactor (CFSTR) (Masten et al., 1996) Following is the expression for rate constants: k= © 2004 by CRC Press LLC [C]0 − [C] θ [C] (14.10) TX69272_C14.fm Page 556 Friday, November 14, 2003 2:13 PM 556 Physicochemical Treatment of Hazardous Wastes where: k is the rate constant [C]0 is the initial concentration [C] is the target concentration θ is the retention time Figure 14.21 illustrates the effect of humic acid or carbonate on the efficiency of the oxidation of TCB The rate of TCB degradation decreased at both 1.6 and 10 mg/L humic acid It appears that humic acid scavenges •OH and other radicals responsible for the degradation of TCB Furthermore, the presence of humic acid is likely to reduce the transmission of UV light, thereby decreasing the rate of ozone decomposition through OH radicals (Masten et al., 1996) For bicarbonate, the rate of TCB degradation decreases with increasing bicarbonate concentration (as shown in Figure 14.21) This is due to the scavenging of OH radicals by bicarbonate The degradation of the target chemical was assumed to be first order with respect to light intensity, [O3], and [•OH] The observed first-order rate constant, k, is given by the following expression: [ ] [ k = kO3 O + k photo φI + kOH• OH• ] (14.11) where: I is the light intensity kO3 is 2.3 M–1 s–1 kphotoφ is 0.0013 W–1 s–1 Equation (14.11) demonstrates that O3, photons, and •OH are all involved in the degradation of TCB, subject to the effect of pH, bicarbonate, and humic acids (Masten et al., 1996) Table 14.17 provides a comparison of the effect of pH on the efficiency of oxidation of pentanoic acid using O3, UV/O3, O3/ H2O2, and UV/O3/H2O2 (Masten et al., 1996) 14.4.6 Polycyclic Aromatic Hydrocarbons (PAHs) PAHs are formed as the by-products of incomplete combustion of fossil fuels These compounds have been identified in many emission sources, such as vehicle exhausts; power plants; chemical, coke, and oil-shale industries; and municipal sewage (Trapido et al., 1995) Some PAHs are known to be carcinogens PAHs have been observed to be degraded by ozone treatment in aqueous media The degradation kinetics of five PAHs — anthracene, © 2004 by CRC Press LLC TX69272_C14.fm Page 557 Friday, November 14, 2003 2:13 PM Combinations of Advanced Oxidation Processes 557 Percent of TCB Remaining 16 14 12 Humic Acid 10 Carbonate No humic acid added, no carbonate added 1.6 mg/L of humic acid, 2.0 mM carbonate 10 mg/L of humic acid, 10 mM carbonate FIGURE 14.21 Degradation of TCB under the influence of humic acid and bicarbonate (From Masten, S et al., J Hazardous Waste Hazardous Mater., 13(2), 265–284, 1996 With permission.) TABLE 14.17 Comparison of the Percentage of PA Remaining under Various Systems Process Ozone Ozone/UV Ozone/H2O2 Ozone/H2O2/UV pH 2.2 7.0 11.5 2.3 6.8 11.0 2.3 6.8 12.2 8.2 PA Remaining (%) 92.2 15.8 31.7 27.0 13.6 16.6 80.9 8.3 22.6 13.2 Note: Input ozone concentration is 127 ± µM; hydrogen peroxide dosage is or 60 µM Source: Masten, S and Davies, S., Environ Sci Technol., 28(4), 180–185, 1994 With permission phenanthrene, pyrene, fluoranthene, and benzopyrene — by UV/O3/H2O2 are discussed in this section Figure 14.22 shows that 90% removal can be achieved within 40 in the degradation of procatechuic acid by the UV/ O3/H2O2 process © 2004 by CRC Press LLC TX69272_C14.fm Page 558 Friday, November 14, 2003 2:13 PM 558 Physicochemical Treatment of Hazardous Wastes Removal Efficiency, % 100 90 80 70 60 50 40 30 20 10 0 10 15 20 30 40 Time, FIGURE 14.22 Degradation of procatechuic acid in UV/ozone/H2O2 treatment (From Trapido, M and Veressinina, Y., Environ Technol., 16, 729–740, 1995 With permission.) 14.4.6.1 Anthracene During ozonation, no differences in the degradation rates of anthracene in acidic and neutral media have been observed In basic media, the degradation of anthracene proceeds remarkably slowly (Trapido et al., 1995) A comparison of the half-lives of anthracene is provided in Table 14.18 14.4.6.2 Pyrene The results obtained in AOP-treatment of pyrene in aqueous solutions were quite similar to those of anthracene and phenanthrene For pyrene, ozonation has been more effective at lower pH values than at neutral pH values The half-lives of pyrene at pH 3, 7, and are 17, 24, and 42 s, respectively; however, the half-life of pyrene increased in the series of O3 < UV/O3 < O3/H2O < UV/ O3/H2O2 (Trapido et al., 1995) The UV degradation of pyrene is quite fast; the half-life is only 69 s (Trapido and Veressinina, 1995) Figure 14.23 illustrates the oxidation kinetics of anthracene and pyrene in neutral media TABLE 14.18 Comparison of the Half-Lives of Anthracene under Various Systems System O3/H2O2 UV/O3 UV/O3/H2O2 O3 Half-Life (s) 30 56 70 26 Source: Data from Trapido, M and Veressinina, Y., Environ Technol., 16, 729–740, 1995 With permission © 2004 by CRC Press LLC TX69272_C14.fm Page 559 Friday, November 14, 2003 2:13 PM Combinations of Advanced Oxidation Processes 559 70 Concentration, mg/L 60 50 Anthracene Pyrene 40 30 20 10 0 20 40 60 80 100 120 140 Time, sec FIGURE 14.23 Oxidation kinetics of anthracene and pyrene in neutral media with UV/ozone/H2O2 system (From Trapido, M and Veressinina, Y., Environ Technol., 16, 729–740, 1995 With permission.) 14.4.6.3 Phenanthrene AOPs have also been applied for phenanthrene degradation in acidic and basic media, as shown in Figure 14.24 The results are similar to those obtained in neutral media Ozonation alone was shown to be the most effective for destruction of phenanthrene Table 14.19 provides the half-lives of phenanthrene under various AOP systems (Trapido and Veressinina, 1995) Figure 14.24 illustrates the degradation kinetics of phenanthrene with the UV/O3/H2O2 system Concentration, mg/L 0.9 0.8 0.7 Phenanthrene 0.6 0.5 0.4 0.3 0.2 0.1 0 35 67 124 181 242 300 Time, sec FIGURE 14.24 Degradation kinetics of phenanthrene with UV/ozone/H2O2 system (From Trapido, M and Veressinina, Y., Environ Technol., 16, 729–740, 1995 With permission.) © 2004 by CRC Press LLC TX69272_C14.fm Page 560 Friday, November 14, 2003 2:13 PM 560 Physicochemical Treatment of Hazardous Wastes TABLE 14.19 Half-Life of Phenanthrene by Various AOPs System Half-Life (s) O3/H2O2 UV/O3 UV/O3/H2O2 O3 58 60 135 56 Source: Data from Trapido, M and Veressinina, Y., Environ Technol., 16, 729–740, 1995 With permission 14.4.6.4 Fluoranthene Table 14.20 provides the half-lives of fluoranthene at various pH values under ozonation, UV degradation, and AOP systems (Trapido and Veressinina, 1995) The half-lives of fluoranthene in AOPs followed the series O3 = UV/O3 < O3/H2O2 < UV/O3/H2O2, as shown in Table 14.21 14.4.6.5 Benzo(a)pyrene Ozonation of benzo(a)pyrene proceeds more effectively in neutral media and is significantly decelerated in basic media Table 14.22 shows that the halflives of benzopyrene in AOPs followed the series O3 = UV/O3 < O3/H2O2 < UV/O3/H2O2 TABLE 14.20 Half-Lives of Fluoranthene by Ozonation or UV at Various pH Half-Life pH Ozonation UV Alone 134 78 357 336 277 753 Source: Data from Trapido, M and Veressinina, Y., Environ Technol., 16, 729–740, 1995 With permission TABLE 14.21 Half-Lives of Fluoranthene by Various AOPs System O3/H2O2 UV/O3 UV/O3/H2O2 O3 Half-Life (s) 86 86 165 78 Source: Data from Trapido, M and Veressinina, Y., Environ Technol., 16, 729–740, 1995 With permission © 2004 by CRC Press LLC TX69272_C14.fm Page 561 Friday, November 14, 2003 2:13 PM Combinations of Advanced Oxidation Processes 561 TABLE 14.22 Half-Lives of Benzo(a)pyrene by Ozonation or Ultraviolet at Different pHs Half-Life pH Ozonation UV Alone 25 19 33 136 110 174 Source: Data from Trapido, M and Veressinina, Y., Environ Technol., 16, 729–740, 1995 With permission 14.4.7 Chlorinated Aliphatic Compounds Zeff and Barich (1992) have illustrated the oxidation of methylene chloride and methanol by various AOP systems Lewis et al (USEPA, 1990) completed a series of studies on VOCs with the Ultrox system at the Lorentz Barrel & Drum Superfund site They concluded that the key difference between ozone and peroxone is the primary oxidation modes: direct oxidation vs hydroxyl radical oxidation Ozone/hydrogen peroxide reacts with aromatic compounds; moreover, it also reacts on aliphatic acids with hydroxyl radicals Due to these conditions, mineralization was slightly higher than with ozone alone The results of these studies showed that DOC mineralization reached 15 and 18% with ozone alone and with an ozone/peroxide system (peroxone), respectively (applied ozone dose of 6.5 mg/L) The ozone process relies heavily on direct oxidation due to molecular ozone, while peroxone relies primarily on oxidation with hydroxyl radical In the peroxone process, the ozone residual is short lived because the added peroxide greatly accelerates the ozone decomposition However, the increased oxidation achieved by the hydroxyl radical greatly outweighs the reduction in direct ozone oxidation because the hydroxyl radical is much more reactive than molecular ozone The net result is that oxidation is more reactive and much faster in the peroxone process than the ozonation process Table 14.23 summarizes the key differences between ozone and peroxone as they relate to their application in drinking water treatment Vermont’s VOC treatment facility at IBM showed increasing treatment efficiency with the addition of hydrogen peroxide The treatment efficiencies increased to an optimal level of 91% and nearly 100% for PCE and TCE at mass ratios of hydrogen peroxide to dissolved ozone of between and 2, as shown in Table 14.24 and Figure 14.25 14.4.8 Fulvic Acids Volk et al (1997) assessed the effects of ozone, ozone/hydrogen peroxide, and catalytic ozone by changes in the organic constituents of a synthetic solution of fulvic acids Initial dissolved organic carbon (DOC) and © 2004 by CRC Press LLC TX69272_C14.fm Page 562 Friday, November 14, 2003 2:13 PM 562 Physicochemical Treatment of Hazardous Wastes TABLE 14.23 Comparison between Ozone and Peroxone Oxidation Factor Ozone decomposition rate Ozone residual Oxidation path Ability to oxidize iron and manganese Ability to oxidize taste and odor compounds Ability to oxidize chlorinated organics Disinfection ability Ability to detect residual for disinfection monitoring Ozone Peroxone Normal decomposition, which produces hydroxyl radical as an intermediate product to 10 Accelerated ozone decomposition, which increases the hydroxyl radical concentration above that of ozone alone Very short lived due to rapid reaction Primarily hydroxyl radical oxidation Usually direct aqueous molecular ozone oxidation Excellent Variable Less effective Good; hydroxyl radical more reactive than for ozone Good; hydroxyl radical more reactive than for ozone Good, but systems can only receive CT credit if they have a measurable ozone residual Poor; cannot calculate CT value for disinfection credit Poor Excellent Good Source: USEPA, Ultrox International Ultraviolet Radiation/Oxidation Technology—Applications Analysis Report, EPA/540/A5-89/012, September 1990 TABLE 14.24 Oxidations of Methylene Chloride and Methanol Contact Time (min) Control 15 25 100 100 100 30 75 75 Ultraviolet UV/H2O2 O3/H2O2 Methylene Chloride 100 100 46 32 17 21 Methanol 75 75 NDA 75 75 NDA 100 59 42 UV/O3 UV/O3/ H2O2 100 36 16 100 19 7.6 75 31 75 1.2 Note: All concentrations are reported in mg/L; NDA = no data available Source: USEPA, Ultrox International Ultraviolet Radiation/Oxidation Technology—Applications Analysis Report, EPA/540/A5-89/012, September 1990 biodegradable dissolved organic carbon (BDOC) concentrations of the fulvic acid solution were 2.84 and 0.23 mg/L, respectively Oxidation tests were performed according to the ozone method, which provides an assessment of the extent of oxidation Ozone, ozone/hydrogen peroxide, and catalytic ozonation mineralized 15, 18, and 24% of the initial DOC, respectively © 2004 by CRC Press LLC TX69272_C14.fm Page 563 Friday, November 14, 2003 2:13 PM Combinations of Advanced Oxidation Processes 563 120 Treatment Effeciency (%) 100 80 60 40 20 0 H2O2/O3 Ratio (wt.WT) PCE 10.5Ib O3/day PCE 15.7Ib O3/day TCE 10.5Ib O3/day TCE 17.5Ib O3/day FIGURE 14.25 Effect of hydrogen peroxide on ozone treatment system at ozone production rates of 10.5 and 15.7 lb/day The x-axis shows the hydrogen peroxide-to-ozone mass ratio The treatment efficiency report is the sum of oxidation and air stripping (From USEPA, Ultrox International Ultraviolet Radiation/Oxidation Technology—Applications Analysis Report, EPA/540/A5-89/ 012, September 1990.) (Figure 14.26) The oxidation system that generated the highest BDOC concentration was ozone/hydrogen peroxide, while catalytic ozone produced the lowest concentrations; with ozone doses greater than 3.5 mg/L, BDOC levels were 0.90, 0.80, and 0.60 mg/L for ozone/hydrogen peroxide, ozone, and catalytic ozone, respectively Catalytic ozone induced oxidation of ozone by-products into CO2 14.4.9 Tomato Wastewaters Beltran et al (1997) reported the results of oxidation of two tomato wastewaters with ozone combined with hydrogen peroxide or UV radiation (254 nm) The oxidation yields of these systems were compared with those from ozonation alone at similar experimental conditions It was found that O3/ H2O2 oxidation leads to the increase of COD degradation rate (e.g., 86% at pH in tomato wastewaters) It can be observed that an increase in hydrogen peroxide concentration, especially above 10–3 M, leads to an increase of the COD and TOC degradation rate, as shown in Figure 14.27 The differences between the oxidation types (O3 and O3/H2O2) diminish with increases in pH (see Figure 14.28) With distillery wastewaters, the presence of hydrogen peroxide barely increases the oxidation rate; however, the combination of UV/O3 radiation was the best oxidation method applied because of the improvements achieved in both COD and TOC reduction rates compared to © 2004 by CRC Press LLC TX69272_C14.fm Page 564 Friday, November 14, 2003 2:13 PM 564 Physicochemical Treatment of Hazardous Wastes DOC reduction (mg/L) 0.8 0.6 0.4 0.2 0 1.5 O3 O3+H2O2 4.5 Cata+O3 Ozone dose (mg/L) FIGURE 14.26 DOC reduction vs applied ozone dose for a fulvic acid solution treated with ozone, ozone/ hydrogen peroxide, or catalytic ozone Contact time = 10 min; pH = 7.5; initial DOC = 2.84 mg/ L (From Volk, C et al., Water Res., 31(3), 650–656, 1997 With permission.) COD (mg/L) 0.8 0.6 0.4 0.2 0 1.5 4.5 Ozone dose (mg/L) FIGURE 14.27 COD vs ozone fed in during oxidation of tomato wastewaters with ozone combined with hydrogen peroxide Conditions: average inlet ozone mass rate = 25.3 mg/min; COD0 = 916 mg O2/L; T = 18°C; pH = 6.3 Ozonation alone: ♦, CH2O2 = 10–3 M; Ⅲ, CH2O2 = 10–2 M; ᭡, CH2O2 = 10–1 M (From Beltran, F.J et al., Water Res., 31(10), 2415–2428, 1997 With permission.) those achieved by ozonation alone, regardless of wastewater type treated As happened to the other oxidation systems, the COD and TOC reductions were higher for tomato wastewater oxidation 14.5 Hydroxyl Radical Concentrations in AOPs From the literature, the rate constants between p-hydroxybenzonic acid and ozone, UV photon, and hydroxyl radical are known (Gurol and Nekouinaini, 1984) Therefore, contribution of ozonation, photolysis, and hydroxyl radical © 2004 by CRC Press LLC TX69272_C14.fm Page 565 Friday, November 14, 2003 2:13 PM Combinations of Advanced Oxidation Processes 565 1.2 COD/COD0 0.8 0.6 0.4 0.2 0 Ozone dose (mg/L) FIGURE 14.28 COD/COD0 vs ozone fed in during oxidation of tomato wastewaters with ozone combined with hydrogen peroxide at different pH values Conditions: average inlet ozone mass rate = 25.9 mg/min; COD0 = 750 mg/L; T = 18°C Ozonation alone: *, pH = 6.3; ×, pH = 11 Ozone/ hydrogen peroxide (H2O2 = 0.02 M): ♦, pH = 6.3; Ⅲ, pH = 9.1; ᭡, pH = 11 (From Beltran, F.J et al., Water Res., 31(10), 2415–2428, 1997 With permission.) to the degradation of p-hydroxybenzonic acid has been estimated by BeltranHeredia et al (2001) Figure 14.29 shows a summary of the importance of each of the three reaction routes (direct photolysis, ozonation, and free radicals) in each of the combined oxidation processes It shows that the combined systems that have the greatest free radical component (>80% of overall oxidation process) are: Fe2+/H2O2, UV/Fe2+/H2O2, UV/Fe2+/H2O2/O3, UV/ H2O2 Since the reaction constant between benzoic acid such as p-hydroxybenzonic acid with the hydroxyl radical is well documented (Ashton et al., 1995), it has been used as a reference compound in calculating the hydroxyl radical concentration Using the comparative method, a value was obtained for the reaction constant of the hydroxyl radical with p-hydroxybenzonic acid of 1.63 × 109 M–1s–1 at 20°C Having determined this constant, the next step was to calculate the concentration of hydroxyl radicals for each of the oxidation systems employed Figure 14.30 shows the values of the hydroxyl radical concentrations for each oxidation system Since UV/Fe2+/H2O2/O3 process has the highest hydroxyl radical concentration, it is not surprising that the system has the highest oxidation efficiency among all the AOPs 14.6 Conclusions Extensive research has been conducted on advanced oxidation systems with two operational elements, such as UV/H2O2, UV/O3, and H2O2/O3; however, not much research has been performed on systems with three © 2004 by CRC Press LLC TX69272_C14.fm Page 566 Friday, November 14, 2003 2:13 PM 566 Physicochemical Treatment of Hazardous Wastes Photolysis Radical O 3/ U U V/ V H 2O H 2O O 3/ 2/F H 2O e2 2/ O Fe 3/ U V/ U V/ H2 O H O 2O 3/ U V/ /F e H 2O 2/ Fe 2 2O H O 3/ O 3/ Fe O U V/ Ti U O V 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Contribution,% Ozonation FIGURE 14.29 Contribution of photolysis, ozonation, and radical reaction in each oxidation process (From Beltran-Heredia, J., Torregrosa, J., Domingues, J.R., and Peres, J.A., Chemosphere, 42, 351-359, 2001 With permission.) 90 80 [OH]*1013, M 70 60 50 40 30 20 10 O 3/ U V/ H 2O 2/ Fe 2/ 2O U V/ H V/ U 2O H 2/ 3/ O Fe 2 Fe 3/ H 2O 2/ 2O O H H V/ U Fe 2O V 3/ U O 2O 3/ H O 3/ F O U V/ Ti O e2 FIGURE 14.30 Values of the hydroxyl radical concentration for each oxidation system (From Beltran-Heredia, J., Torregrosa, J., Domingues, J.R., and Peres, J.A., Chemosphere, 42, 351-359, 2001 With permission.) operational elements, such as UV/O3/H2O2 system This is due to the increased cost of three different oxidation systems and the limited number of compounds that can be treated effectively VOCs have been successfully © 2004 by CRC Press LLC TX69272_C14.fm Page 567 Friday, November 14, 2003 2:13 PM Combinations of Advanced Oxidation Processes 567 treated by the UV/oxidation process Compounds that have been oxidized include TCE, methanol, and methyl chloride Ozonation has been shown to be quite effective for the destruction of PAHs in neutral media The effect of pH on the oxidation of pollutants played a major role in the AOP systems studied Using p-hydroxybenzoic acid as the reference compound, UV/O3/ H2O2/Fe2+ process produces the highest hydroxyl radical concentration of 7.8 × 10–12 M and has the highest degradation efficient among the ten different AOP systems studied by Beltran-Heredia et al (2001) References Alaton, I.A., Balcioglu, I.A., and Bahnemann, D.F., Advanced oxidation of a reactive dyebath effluent: comparison of O3, H2O2/UV-C and TiO2/UV-A processes, Water Res., 36, 1143–1154, 2002 Ashton, L., Buxton, G.V., and Stuart, C.R., Benzoic acid, rate constant with hydroxyl radical, J Chem Soc Faraday Trans., 91, 1631–1633, 1995 Bahnemann, D and Hart, E.J., Mechanism of the hydroxide ion initiated decomposition of ozone in aqueous solution, J Phys Chem., 86(2), 255–259, 1982 Beltran, F.J., Kolaczkowski, S.T., Crittenden, B.D., and Rivas, F.J., Degradation of orthochlorophenol with ozone in water, Trans I Chem Eng., 71(B), 57–65, 1993 Beltran, F.J., Encinar, J.M., and Gonzalez, J.F., Industrial wastewater advanced oxidation Part 2: Ozone combined with hydrogen peroxide or UV radiation, Water Res., 31(10), 2415–2428, 1997 Beltran-Heredia, J., Torregrosa, J., Domingguez, J., and Peres, J.A., Comparison of the degradation of p-hydroxybenzoic acid in aqueous solution by several oxidation processes, Chemosphere, 42, 351–359, 2001 Benitez, F.J., Beltan-Heredia, J., Acero, J.L., and Rubio, F.J., Contribution of free radicals to chlorophenols decomposition by several advanced oxidation processes, Chemosphere, 41, 1271–1277, 2000 Bielski, B.H.J., Cabelli, D.E., Arudi, R.L., and Ross, A.B., J Phys Chem Ref Data, 14, 1041–1100, 1985 Boncz, M.A., Bruning, H., Rulkens, W.H., Sudholter, E.J.R., Harmsen, G.H., and Bijsterbosh, J.W., Kinetic and mechanistic aspects of the oxidation of chlorophenols by ozone, Water Sci Technol., 35(4), 65–72, 1997 Buhler, R.E., Staehelin, J., and Hoigne, J Ozone decomposition in water studied by pulse radiolysis: HO2/O2, and HO3/O3 as intermediates, J Phys Chem., 88, 2560–2564, 1984 Burrows, H.D., Ernestova, L.S., Kemp, T.J., Skurlatov, Y.I., Purmal, A.P., Yermakov, A.N., Kinetics and mechanism of photodegradation of chlorophenols, Progress Chem Kinet., 23(3), 145–207, 1998 Christensen, H., Sehested, K., and Corfitzen, H., Reactions of hydroxyl radicals with hydrogen peroxide at ambient and elevated temperatures, J Phys Chem., 86(a), 1588–1590, 1982 © 2004 by CRC Press LLC TX69272_C14.fm Page 568 Friday, November 14, 2003 2:13 PM 568 Physicochemical Treatment of Hazardous Wastes Esplugas, S., Gimenez, J., Contreras, S., Pascual, E., and Rodriguez, M., Comparison of different advanced oxidation processes for phenol degradation, Water Res., 36, 1034–1042, 2002 Gurol, M and Nekouinaini, S., Kinetics behavior of ozone in aqueous solutions of substituted phenols, Ind Eng Chem Fundam., 23, 54–60, 1984 Hong, A., Zappi, M., Kuo, C.-H., and Hill, D., Modeling kinetics of illuminated and dark advanced oxidation processes, J Environ Eng., 122(1), 58-62, 1996 Lewis, N., Topudurti, K., Welshans, G., and Foster, R., A field demonstration of the UV/oxidation technology to treat ground water contaminated with VOCs, J Air Waste Manage Assoc., 40(4), 540–547, 1990 Masten, S and Davies, S., The use of ozonation to degrade organic contaminants in wastewaters, Environ Sci Technol., 28(4), 180–185, 1994 Masten, S., Shu, M., Galbraith, M., and Davies, S., Oxidation of chlorinated benzenes using advanced oxidation processes, J Hazardous Waste Hazardous Mater., 13(2), 265–284, 1996 Ni, C.H and Chen, J.N., Heterogeneous catalytic ozonation of 2-chlorophenol aqueous solution with alumina as a catalyst, Water Sci Technol., 43(2), 213–220, 2001 Peyton, R and Glaze, W Destruction of pollutants in water with ozone in combination with ultraviolet radiation: Photolysis of aqueous ozone Environ Sci Technol 22, 761–767, 1988 Saucer, M.L Jr., Brown, W.G., and Hart, E.J., O(P)atom formation by the photolysis of hydrogen peroxide in alkaline aqueous solutions, J Phys Chem., 88(7), 1398–1400, 1984 Sehested, K., Holcman, J., Bjerbakke, E., and Hart, E., A pulse radiolysis study of the reaction OH + O3 in aqueous medium, J Phys Chem., 88(8), 4144–4147, 1984 Sotelo, J.L., Beltran, F.J., Benitez, F.J., and Beltran-Heredia, J., Henry’s law constant for the ozone-water system, Water Res., 23, 1239–1246, 1989 Staehelin, J and Hoigne, J., Decomposition of ozone in water: rate of initiation by hydroxide ions and hydrogen peroxide, Environ Sci Technol., 16(10), 676–681, 1982 Staehelin, J and Hoigne, J., Decomposition of ozone in water in the presence of organic solutes acting as promoters and inhibitors of radical chain reactions, Environ Sci Technol., 19, 1206–1213, 1985 Takahashi, N., Nakai, T., Satoh, Y., and Katoh, Y., Variation of biodegradability of nitrogenous organic compounds by ozonation, Water Res., 28(7), 1563–1570, 1994 Tang, W.Z and Huang, C.P., 2,4-Dichlorophenol oxidation kinetics by Fenton’s reagent, Environ Technol., 17, 1371–1378, 1996 Trapido, M., Veressinina, Y., and Munter, R., Ozonation and advanced oxidation processes of polycyclic aromatic hydrocarbons in aqueous solutions: a kinetic study, Environ Technol., 16, 729–740, 1995 USEPA, Ultrox International Ultraviolet Radiation/Oxidation Technology—Applications Analysis Report, EPA/540/A5-89/012, September 1990 Volk, C., Roche, P., Joret, J.C., and Paillard, H., Comparison of the effect of ozone, ozone/hydrogen peroxide system and catalytic ozone on the biodegradable organic matter of a fulvic acid solution, Water Res., 31(3), 650–656, 1997 Weeks, J.L and Rabani, J., The pulse radiolysis of deaerated aqueous carbonate solutions I: Transient optical spectrum and mechanism; II: pK for OH radicals, J Phys Chem., 70(7), 2100–2106, 1966 © 2004 by CRC Press LLC TX69272_C14.fm Page 569 Friday, November 14, 2003 2:13 PM Combinations of Advanced Oxidation Processes 569 Zappi, M.E., Hong, A., and Cerar, R., Treatment of groundwater contaminated with high levels of explosives using traditional and non-traditional advanced oxidation processes, HMCRI Superfund Conf., Washington D.C., 1993 Zeff, J.D and Barich, J., UV/oxidation of organic contaminants in ground, waste and leachate waters, Water Pollut Res J Can., 27(1), 139–150, 1992 © 2004 by CRC Press LLC [...]... not a “listed” waste, but instead a characteristic waste, and the mixture does not exhibit any of the characteristics, the mixture is not considered hazardous The “derived from” rule states that any waste derived from the treatment of a “listed” hazardous waste remains a hazardous waste Similar to the mixture rule, if the by-product of a characteristic waste does not exhibit any of the hazardous characteristics,... disposal ban for hazardous wastes This land ban states that no hazardous waste can be disposed of on land until it has been treated to have concentrations of chemicals under a certain level The USEPA was given the responsibility to create these levels and provide a proper treatment method for each waste The universe of hazardous waste was broken down into three categories; these groups of waste were evaluated,... (the Hazardous and Solid Waste Amendments) RCRA is the broadest federal law covering the management of solid waste, and it has established a “cradle to grave” ideology It regulates waste through all aspects of its life, from waste generators to storage facilities, transportation, treatment, and finally disposal An important goal of the RCRA is to reduce or eliminate the generation of hazardous waste. .. environment when improperly treated, stored, transported, disposed of, or otherwise managed © 2004 by CRC Press LLC TX69272_C01.fm Page 10 Tuesday, November 11, 2003 11:33 AM 10 Physicochemical Treatment of Hazardous Wastes The two classes of hazardous waste as defined by RCRA are characteristic waste and “listed” waste Characteristic waste is defined by the properties it exhibits The four characteristic... automatically becomes a hazardous waste storage facility and must comply with the stricter TSD rules (Davenport, 1992) The RCRA has also outlined a set of systematic rules governing the transport of hazardous waste A detailed manifest system was established, where a manifest is to be prepared for each shipment of hazardous waste The manifest includes information on the generator, the nature of the waste, and the... AM 12 Physicochemical Treatment of Hazardous Wastes down to a crawl For example, as mentioned previously, the RCRA required the USEPA to develop a list of harmful wastes to be regulated Although over 1000 chemicals were likely to qualify for the list and 450 were identified in 1980, only five new types of waste were identified in the next 6 years (Rosenbaum, 1995) One of the main components of the... characteristics, it is not considered hazardous The USEPA established a Hazardous Waste Identification Rule (HWIR), which allows certain types of low-risk waste listed as hazardous by the USEPA to be exempt from hazardous waste regulations, as long as they can be safely handled as solid waste (USEPA, 1998a) The agency established risk level criteria according to affects of the waste on health and the environment... goal of the CERCLA, however, is to clean up the hazardous waste sites It authorizes the USEPA to order PRPs to remediate waste sites or remove hazardous substances The USEPA or PRPs can develop a preliminary nonbinding allocation of responsibility (NBAR), which divides the © 2004 by CRC Press LLC TX69272_C01.fm Page 14 Tuesday, November 11, 2003 11:33 AM 14 Physicochemical Treatment of Hazardous Wastes... contributors at hundreds of Superfund sites By settling with the USEPA, small polluters are not dragged into the problems of bigger polluters Hazardous wastes must be either removed or remediated through longterm remedial action Removal is merely the elimination of any further release of the hazardous waste The three types of removal actions are: • Classic emergency removal actions of a waste that poses an... more than 100 kg of © 2004 by CRC Press LLC TX69272_C01.fm Page 11 Tuesday, November 11, 2003 11:33 AM Environmental Laws 11 hazardous waste in any one month qualifies as a hazardous waste generator and requires a USEPA generator identification number As the constant removal of hazardous waste from a generation facility could become incredibly expensive, the RCRA allows hazardous wastes to be stored