Nitrification Prevention and Control in Drinking Water AWWA MANUAL M56 Second Edition Copyright © 2013 American Water Works Association. All Rights Reserved. Manual of Water Supply Practices — M56, Second Edition Nitrification Prevention and Control in Drinking Water Copyright © 2006, 2013, American Water Works Association All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information or retrieval system, except in the form of brief excerpts or quotations for review purposes, without the written permission of the publisher. Disclaimer The authors, contributors, editors, and publisher do not assume responsibility for the validity of the content or any consequences of its use. In no event will AWWA be liable for direct, indirect, special, incidental, or consequential damages arising out of the use of information presented in this book. In particular, AWWA will not be responsible for any costs, including, but not limited to, those incurred as a result of lost revenue. In no event shall AWWA’s liability exceed the amount paid for the purchase of this book. Project Manager/Senior Technical Editor: Melissa Valentine Manuals Specialist: Molly Beach Cover Art: Melanie Yamamoto Production: TIPS Technical Publishing, Inc. Library of Congress Cataloging-in-Publication Data Nitrification prevention and control in drinking water / [edited by] Jan Routt, Janice Skadsen. -- Second edition. pages cm. -- (AWWA manual ; M56) First edition published as: Fundamentals and control of nitrification in chloraminated drinking water distribution systems, copyrighted in 2006. Includes bibliographical references. ISBN 978-1-58321-935-5 1. Water--Purification--Nitrogen removal. 2. Water--Purification--Chloramination. 3. Nitrification-- Prevention. 4. Denitrification. 5. Drinking water--Contamination--Prevention. I. Routt, Jan. II. Skadsen, Janice. III. American Water Works Association. IV. Fundamentals and control of nitrification in chloraminated drinking water distribution systems. TD427.N5N5855 2013 628.1’662--dc23 2012050481 ISBN 10: 1-58321-935-8 ISBN 13: 978-1-58321-935-5 eISBN 10: 1-61300-228-9 eISBN 13: 978-1-61300-228-5 American Water Works Association 6666 West Quincy Avenue Denver, CO 80235-3098 303.794.7711 www.awwa.org Printed on recycled paper Copyright © 2013 American Water Works Association. All Rights Reserved. Contents List of Figures, vii List of Tables, xiii Preface, xv Acknowledgments, xvii Chapter 1 Introduction and Impact on Regulatory Compliance . . . . . . . . .1 Introduction, 1 Distribution System Disinfection Practices, 3 History of Chloramination In The United States, 5 Nitrification Basics, 7 Nitrification and Regulatory Compliance, 9 Conclusions, 16 References, 18 Chapter 2 Nitrification in Water and Wastewater Treatment . . . . . . . . . . .21 Introduction, 21 Drinking Water Nitrification and Impact on Distribution Systems, 21 Nitrification in Wastewater Treatment, 32 Comparisons Between Nitrification in Water and Wastewater, 42 Conclusions, 44 References, 45 Chapter 3 Nitrification in Chloraminated Drinking Water Distribution Systems – Occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49 Introduction, 49 Nitrification in Chloraminated Drinking Water Distribution Systems, 51 Nitrification in Chloraminated Water Storage Facilities, 57 Conclusions, 63 Disclaimer, 63 References, 64 Chapter 4 Overview of Causes and Control of Nitrification in Chloraminated Drinking Water Distribution Systems . . . . . . . . . . . . . . .67 Introduction, 67 Conditions Promoting and Limiting Growth of Nitrifying Bacteria in Drinking Water Distribution Systems, 68 Chloramine Chemistry — As Major Cause of Nitrification, 70 Sources and Treatment as Nitrification Causes and Controls, 75 iii Copyright © 2013 American Water Works Association. All Rights Reserved. Distribution Configuration and Operations as Nitrification Causes and Controls, 87 Conclusions, 91 Disclaimer, 93 References, 94 Chapter 5 Microbiology, Isolation, and Detection of Nitrifying Microorganisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 Introduction, 97 Taxonomy, Morphology, and Physiology of Nitrifying Microorganisms, 98 Isolation and Enumeration of Nitrifying Bacteria, 112 Conclusions, 117 References, 119 Chapter 6 Growth and Inactivation of Nitrifying Microorganisms . . . . .127 Introduction, 127 Growth Conditions for Ammonia- and Nitrite-Oxidizing Bacteria, 127 Inactivation by Disinfectants, 139 Conclusions, 149 References, 150 Chapter 7 Monitoring for Nitrification Prevention and Control . . . . . . . .155 Introduction, 155 Monitoring Program Goals and Parameters, 156 Relative Usefulness of Monitoring Parameters, 157 Description of Monitoring Parameters, 158 Ammonia, Free and Total, 161 Monitoring Frequency, 172 Conclusions, 174 References, 174 Chapter 8 Operational and Treatment Practices to Prevent Nitrification . . .177 Introduction, 177 Utility Practices Impacting Nitrification, 180 Traditional Approaches to Nitrification Prevention, 180 Monochloramine Residual, 193 Storage Facility Operation, 196 Distribution System Operation, 202 Alternative Approaches to Nitrification Prevention, 207 Assessment of Effectiveness of Preventative Operational Measures, 218 Conclusions, 220 References, 222 Chapter 9 Assessment and Operational Responses to Nitrification Episodes . .227 Introduction, 227 iv Copyright © 2013 American Water Works Association. All Rights Reserved. Nitrification Assessment, 228 Developing a Nitrification Response Plan, 234 Responses to Distribution System Nitrification Episodes, 239 Responses to Nitrification Episodes in Distribution System Storage Facilities, 252 Conclusions, 258 References, 258 Chapter 10 Engineering/Capital Improvements for Nitrification Prevention . .261 Introduction, 261 Improvements to Reservoir Mixing and Decrease Water Age, 262 Piping, 272 Boosting Combined Chlorine Residual in Chloraminated Distribution Systems, 273 Conclusions, 284 References, 284 Abbreviations & Acronyms, 287 Units of Measure with Metric Conversions, 291 Index, 295 List of Manuals, 301 v Copyright © 2013 American Water Works Association. All Rights Reserved. Copyright © 2013 American Water Works Association. All Rights Reserved. Figures 1-1 Main biological processes involving nitrogen transformation, 8 1-2 Ammonia loss % and final pH, versus time when initial alkalinity was reduced in stages from 100 to 0 mg/L as CaCO , 13 3 1-3 Theoretical nitrite/nitrate production based on chloramine decay stoichiometry as a function of chlorine:ammonia-N ratio. Assumes: (1) 100% decay according to Reaction 3 in Table 1-3; (2) 100% conversion of ammonia to nitrite/nitrate-N, 15 1-4 THM inhibition of nitrification during bench-scale studies,17 2-1 Ammonia levels before and after biofiltration at ACWD, 28 2-2 Heterotrophic plate count bacteria released from biologically active drinking water filter and treated with UV, chlorine, and chloramines, 31 2-3 Integrated fixed film activated sludge system treatment process, 34 2-4 Integrated fixed film activated sludge system treatment process. Bottom photos (L to R) show a media filled basin and media size, 35 2-5 Cross section of a biologically active wastewater filtration process, 35 2-6 Illustration of the Dual-Tank SHARON process, 36 2-7 Typical plastic media used in deammonification MBBR systems. Effective specific surface areas: AnoxKaldnes K1 and K3 media—500 m2/m3; BiofilmChip® M—1,200 m2/m3; Anox™K5 media—800 m2/m3, 40 2-8 Deammonification in a biofilm, 41 2-9 Demon SBR at the Strass WWTP (Austria) – left; SBR control strategy – right, 42 2-10 Granulated anammox biomass from a DEMON SBR, 43 3-1 Nitrification episode in a South Australian distribution system. Relationship between: (a) nitrite and nitrate concentrations, (b) oxidized nitrogen concentrations, (c) total chlorine residual, and (d) numbers of nitrifying bacteria, 58 3-2 Seasonal relationship between temperature, AOB, and nitrite in the Orange County reservoir in California, 61 4-1 Monochloramine decay as a function of Cl/N molar ratio. Cl/N = 0.5(,), Cl/N = 0.6(,), and Cl/N = 0.7(,). Open symbols are for pH≈7.5 and filled symbols are for pH≈6.5 [NH Cl] = 0.05 mM, C = 4 mM, μ = 0.1 M, 2 0 T,CO3 T=25°C, 73 4-2 Effect of pH on monocloramine decay (autodecomposition) as a function of pH at 25°C; 4mg/L Cl = 0.056 mM NH Cl, 75 2 2 vii Copyright © 2013 American Water Works Association. All Rights Reserved. 4-3 Effect of total carbonate concentration on monochloramine decay at (A) pH≈6.6, (B) pH≈7.6, and (C) pH≈8.3. Cl/N = 0.7 mol mol–1, μ = 0.1 M, T = 25°C, 76 4-4 Effect of temperature on monochloramine decomposition. Cl/N = 0.7 mol mol–1, pH = 7.5, C = 10 mM, μ = 0.1 M, 77 T,CO3 4-5 Effect of 0–3mgL–1 bromide on monochloramine decomposition at pH≈7.5. Cl/N = 0.7 mol/mol, C = 4 mM, μ = 0.1 M, T = 25°C, 77 T,CO3 4-6 Impact of bromide on chloramine decay, 78 4-7 Impact of coagulation of ozonation on chloramine demand. Chloramine demand/decay profile: 20°C, pH = 8.9, 80 4-8 Effect of TOC removal by GAC adsorption on chloramine demand. Ozonated, filtered effluent and GAC effluent blends; 20°C, pH = 8.5, 81 4-9 Effect of inert and biologically active filtration on chloramine demand. Ozanated and filtered water; 20°C, pH = 8.5, 84 4-10 Effect of membrane filtration on chloramine demand. Settled, ozonated, and biofiltered (old GAC/sand) water, pH = 8.7; 20°C (no free Cl contact time), 2 85 4-11 Effect of postfilter chlorine dioxide dose on chloramine demand. Filter effluent; TOC – 3.2 mg/L, O – 0 mg/L, pH – 8.5, 20°C, 86 3 5-1 Phylogenetic tree of AOB based on multiple alignment of 55 nearly full- length AOB 16S rDNA sequences. Abbreviations are Nm for Nitrosomonas, Nc for Nitrosococcus, and Ns for Nitrosospira. R. eutropha is a non-AOB member of the Betaproteobacteria subphylum. Scale bar represents 10% sequence difference, 100 5-2 Nitrosomonas europaea ATCC 25978; phase-contrast photomicrograph (bar, 5 µm), 103 5-3 Nitrosomonas species terrestrial strains; phase-contrast photomicrograph (bar, 5 μm), 103 5-4 Nitrosomonas species isolated from a drinking water reservoir; transmission electron micrograph (bar, 0.1 µm), 104 5-5 Nitrosospira briensis negatively stained cell; electron micrograph (bar, 1 µm), 104 5-6 Phylogenetic tree of NOB based on a multiple alignment of 40 NOB 16S rDNA sequences. Abbreviations are Nb for Nitrobacter and Nsr for Nitrospira. Rh. capsulatus is in the Alphaproteobacteria class, R. eutropha is in the Betaproteobacteria class, and E. coli is in the Gammaproteobacteria class. Scale bar represents 10% sequence difference, 105 5-7 Nitrococcus mobilis (bar, 5 µm), 107 5-8 Nitrifying bacterial zoogloea (loose aggregate of Nitrosomonas europaea cells); electron micrograph (bar, 1 µm), 109 viii Copyright © 2013 American Water Works Association. All Rights Reserved. 5-9 Nitrifying bacterial cyst (compact aggregate of Nitrosomonas europaea cells); electron micrograph (bar, 1 µm), 109 5-10 Typical microprofiles of oxygen, ammonium ion, nitrite, and nitrate concentrations in nitrifying aggregates. The gray area marks the zone with nitrifying activity; negative distance indicates water phase and positive distance represents the biofilm, 111 6-1 Generalized graph of Monod and Haldane kinetics, showing the comparative specific growth rate of an ammonia-insensitive strain characterized by Monod kinetics (µˆ = 1 d-1, K = 10 mg N/L) and an ammonia-sensitive strain s characterized by Haldane kinetics (µˆ = 0.5 d-1, K = 1 mg N/L, K = 100 mg s i N/L), 131 6-2 Optimum temperature as a function of substrate concentration. (Note: The circles indicate the optimum temperatures corresponding to a substrate concentration of 1 mg/L N.) 135 6-3 Maximum rate of oxidation as a function of substrate concentration, 135 6-4 Effect of pH on maximum specific growth rate of Nitrobacter species, 136 6-5 Effect of temperature and pH on unionized ammonia (NH ), 137 3 6-6 The pH dependence of the ammonia oxidation maximum-velocity coefficient for Nitrosomonas europaea, 138 6-7 The pH dependence of the ammonia oxidation rate for Nitrosomonas europaea, 138 6-8 Inactivation of nitrifying bacteria by monochloramine, 142 6-9 Relationship between the first-order inactivation rate constant and pH, 144 6-10 Data and fitted regression plots for BacLight-based Nitrosomonas europaea inactivation experiments using the Chick–Watson model (n = 1), 144 6-11 Distribution of mono- and dichloramine as a function of pH, 145 6-12 Distribution of hypochlorous acid and hypochlorite ion as a function of pH, 146 7-1 HPC-plate count agar as an indicator of nitrification at various total chlorine and nitrite levels in a California distribution system, 167 7-2 HPC-R2A as an indicator of nitrification at various total chlorine and nitrite levels in a California distribution system, 168 7-3 Relative counts: Plate count agar versus R2A agar in a Florida distribution system, 168 8-1 Utility practices and perceptions regarding prevention of nitrification. Number of responding utilities = 50, 181 8-2 Correlations between free ammonia, temperature, total chlorine residual, and nitrite concentration, 181 ix Copyright © 2013 American Water Works Association. All Rights Reserved. 8-3 Example of an aqua ammonia (ammonium hydroxide) storage tank and metering pump, 184 8-4 Example of an anhydrous ammonia feed system, 185 8-5 Calcium carbonate precipitation removed from an ammonia injector, 187 8-6 Direct ammonia feed system, 189 8-7 Example of control schematic for monochloramine formation, 190 8-8 Comparison of ammonia feed rates (as pumped) versus stock used (as weight). A problem is indicated by the diverging hypothetical data late in the month, 192 8-9 Example of stratification and temperature monitoring in a storage facility, 197 8-10 The effect of inlet momentum on mixing characteristics of a 1-mil gal elevated storage tank using CFD modeling, 199 8-11 Difference in flow pattern and pipe velocity with conventional and unidirectional flushing. The numbers on the charts are water velocities in ft/ sec, 203 8-12 Example of programmable auto flush device, 205 8-13 Relationships between total chlorine residual and HPC levels with booster chloramination at Golden State Water Company, 208 8-14 Impact of booster chloramination on nitrification, 208 8-15 Reduction in nitrite levels following water blending, 210 8-16 Correlation of pH and nitrite at a distribution system sampling location, 212 8-17 Limited nitrification in Ann Arbor Water System after 15 years of operation at pH 9.3, 213 8-18 Monochloramine stability and pH, 214 8-19 Free ammonia and pH, 214 8-20 Survival of AOB as affected by chlorite ion, 216 8-21 Control of Nitrification by use of chlorite ion, 216 8-22 Loss of nitrification control in the presence of chlorite ion, 217 8-23 Nitrification control by use of chlorite ion in Louisville Water System, 218 8-24 Photo of full-scale UV light application in storage facility, 219 8-25 Low Intensity UVA Radiation Installed in Storage Facility for Inhibition of Nitrification at LA, 220 9-1 Nitrification assessment flowchart, 231 9-2 Example of distribution system nitrification assessment, 234 9-3 Example of nitrification response decision tree, 237 9-4 Utility survey of effectiveness of various nitrification responses, 238 x Copyright © 2013 American Water Works Association. 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