A Guide to Preparing for Wastewater Treatment … Guide to Preparing for Wastewater Treatment Certification Exams First Edition John Giorgi CertifiCation Study Guide Wastewater operator

A Guide to Preparing for Wastewater Treatment Certification Exams

First Edition

John Giorgi

CertifiCation Study Guide

Wastewater operator

WW OpCert SG FINAL01.indb 1 6/26/2009 12:23:09 PM

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Wastewater Operator Certification Study Guide: A Guide to Preparing for Wastewater Treatment Certification ExamsCopyright © 2009 American Water Works Association

AWWA Publications Manager: Gay Porter De NileonProject Manager: Martha Ripley GrayCopy Editor: Deborah J. LynesProduction: Carrie MattoxCover Art: Cheryl Armstrong

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.

DisclaimerAlthough this study guide has been extensively reviewed for accuracy, there may be an occasion to dispute an answer, either factually or in the interpretation of the question. AWWA has made every effort to correct or eliminate any questions that may be confusing or ambiguous. If you do find a question that you feel is confusing or incorrect, please contact the AWWA Publishing Group.

Additionally, it is important to understand the purpose of this study guide. It does not guarantee cer-tification. It is intended to provide the operator with an understanding of the types of questions he or she will be presented with on a certification exam and the areas of knowledge that will be covered. AWWA highly recommends that you make use of the additional resources listed at the end of this study guide in preparing for your exam.

Library of Congress Cataloging-in-Publication DataGiorgi, John.Wastewater operator certification study guide : a guide to preparing for wastewater treatment certi-fication exams / by John Giorgi. -- 1st ed. p. cm. Includes bibliographical references. ISBN 978-1-58321-728-3

1. Sewage--Purification--Examinations--Study guides. 2. Sewage disposal plants--Examinations --Study guides. 3. Sanitary engineers--Certification--United States--Examinations--Study guides. I. Title.

TD745.G565 2009628.3076--dc22

2009011271

6666 West Quincy AvenueDenver, CO 80235-3098303.794.7711www.awwa.org


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Contents

List of Figures, viiPreface, ixAcknowledgments, xi

Grade 1 Questions, 1Wastewater Sources and Characteristics, 1Basic Wastewater Treatment, 2Wastewater Treatment Facilities, 3Preliminary Treatment, 3Racks, Screens, Comminutors, and Grit Removal, 4Primary Sedimentation, 4Sedimentation and Flotation, 4Secondary Treatment Processes, 5Activated Sludge, 5Waste Treatment Ponds, 6Odor Control, 6Phosphorus Removal, 7Disinfection, 7Wastewater Solids Processing, 7Sampling, Testing, and Reporting, 8Maintenance, 10Safety, 10Basic Chemistry, 12

Grade 1 Answers and References, 15

Grade 2 Questions, 25General Wastewater Treatment Principles, 25Wastewater Treatment Facilities, 25Wastewater Sources and Characteristics, 27Racks, Screens, Comminutors, and Grit Removal, 28Sedimentation and Flotation, 28Secondary Treatment Processes, 29Activated Sludge, 30


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Trickling Filters, 33Rotating Biological Contactors, 34Waste Treatment Ponds, 35Sludge Digestion and Solids Handling, 36Odor Control, 40Enhanced Biological (Nutrient) Control, 41Disinfection, 41Solids Removal from Secondary Effluents, 42Effluent Disposal, 43Wastewater Solids Processing, 43Residual Solids Management, 46Water and Wastewater Microbiology, 47Maintenance, 47Safety, 48Basic Chemistry, 49


Grade 3 Questions, 67General Wastewater Treatment Principles, 67Wastewater Treatment Facilities, 68Wastewater Sources and Characteristics, 69Racks, Screens, Comminutors, and Grit Removal, 69Sedimentation and Flotation, 70Activated Sludge, 71Trickling Filters, 74Rotating Biological Contactors, 76Waste Treatment Ponds, 77Sludge Digestion and Solids Handling, 79Odor Control, 81Phosphorus Removal, 82Enhanced Biological (Nutrient) Control, 83Disinfection, 84Solids Removal from Secondary Effluents, 85Effluent Disposal, 86Residual Solids Management, 86Wastewater Reclamation and Reuse, 88Water and Wastewater Microbiology, 90Basic Chemistry, 91



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Grade 4 Questions, 111General Wastewater Treatment Principles, 111Sedimentation and Flotation, 112Activated Sludge, 112Trickling Filters, 120Rotating Biological Contactors, 121Waste Treatment Ponds, 122Sludge Digestion and Solids Handling, 123Odor Control, 124Phosphorus Removal, 124Enhanced Biological (Nutrient) Control, 125Disinfection, 126Solids Removal from Secondary Effluents, 127Residual Solids Management, 129Water and Wastewater Microbiology, 133Basic Chemistry, 134


Grades 1–4 Pumping Questions, 155Grade 1 Pumping Questions, 155

Basic Water Hydraulics, 155Introduction to Centrifugal Pumps, 155Centrifugal Pump Components, 156Centrifugal Pumps—Theory, 157Pump Nomenclature, 157Mechanical Seals, 158

Grades 2–4 Pumping Questions, 158Basic Water Hydraulics, 158Centrifugal Pumps—Theory, 159Centrifugal Pumps—Types, 160Pump Nomenclature, 160Replacement of Pump Components on End Suction Centrifugal Pumps, 161Selection and Replacement of Packing, 162Pump Piping System, 163End Suction and Split-Case Centrifugal Pumps, 163Line Shaft Turbine Operating Conditions, 164Special Pumping Units, 164Introduction to Centrifugal Pumps, 165Centrifugal Pump Components, 166Centrifugal Pumps: Operational Procedures, 168Centrifugal Pump: Maintenance Procedures, 168Centrifugal Pump: Lubrication, 168


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Centrifugal Pump: Troubleshooting, 169Centrifugal Pump: Modifications, 170Positive-Displacement Pumps, 170

Grades 1–4 Pumping Answers and References, 171Math Questions, 181Answers to Math Questions, 195Math Questions with Solutions, 197Appendix A—Common Conversion Factors, 229Appendix B—Summary of Wastewater Treatment Equations (All Grades), 233Appendix C—Wastewater Flowchart Diagrams, 255Appendix D—Abbreviations, 269References, 273


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Figures

Figure 1 Flowchart of Typical Wastewater Treatment Processes, 256Figure 2 Flowchart of Conventional Activated Sludge Process, 257Figure 3 Flowchart of Contact Stabilization Process, 258Figure 4 Flowchart of Activated Sequencing Batch Reactor, 259Figure 5 Flowchart of Typical Wastewater Treatment Using Ponds after Secondary Treatment, 260Figure 6 Flowchart of Typical Wastewater Treatment Using Polishing Ponds in Series Treatment, 261Figure 7 Flowchart of Wastewater Treatment Using Rotating Biological Contactor Process, 262Figure 8 Flowchart of Typical Wastewater Treatment Using an Oxidation Ditch, 263Figure 9 Flowchart of Typical Wastewater Treatment Using Electrodialysis or Nanofiltration, 264Figure 10 Flowchart of Typical Wastewater Treatment Using a Membrane Bioreactor, 265Figure 11 Flowchart of Wastewater Treatment Nitrification Process, 266Figure 12 Flowchart of Wastewater Treatment Plant Processing Sludge, 267


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This work is dedicated to my wife, Flora Zhou Giorgi; my children, Sara, Stephanie, and Steve; my mother, Thelma Giorgi; and my father, Albert Peter Giorgi.


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Preface

This guide is intended to give operators practice answering questions that are similar in format and content to the questions that appear on certification exams. The questions in this study guide are not the same questions that will appear on the certification exam. However, the questions allow operators to experience the types of questions that may be on a certifi-cation exam. If you have difficulty answering any of the questions in this study guide, you should consult the reference source provided following the answer to the question.

American Water Works AssociationAWWA is an international nonprofit and educational society and the largest and oldest organization of water professionals in the world. Its more than 55,000 members represent the full spectrum of the water community: treatment plant operators and managers, scientists, environmentalists, manufacturers, academicians, regulators, and others who hold genuine interest in water supply and public health. Membership includes more than 4,600 utilities that supply water to roughly 180 million people in North America. Through our collective strength, we become better stewards of water for the greatest good of the people and the environment.

Founded in 1881, AWWA provides knowledge, information, and advocacy to improve the quality and supply of water in North America and beyond. AWWA advances public health, safety, and welfare by uniting the efforts of the full spectrum of the water community.


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A Guide to Preparing for Wastewater Treatment … Guide to Preparing for Wastewater Treatment Certification Exams First Edition John Giorgi CertifiCation Study Guide Wastewater operator