cost estimating manual for water & wastewater treatment facilities

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COST ESTIMATING MANUAL FORWATER TREATMENT FACILITIES

Cost Estimating Manual for Water Treatment Facilities William McGivney and Susumu KawamuraCopyright 2008 John Wiley & Sons, Inc. ISBN: 978-0-471-72997-6


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COST ESTIMATINGMANUAL FOR

WATER TREATMENTFACILITIES

William McGivneySusumu Kawamura

John Wiley & Sons, Inc.


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This book is printed on acid-free paper. *1

Copyright # 2008 by John Wiley & Sons, Inc. All rights reserved

Published by John Wiley & Sons, Inc., Hoboken, New JerseyPublished simultaneously in Canada

No part of this publication may be reproduced, stored in a retrieval system, or transmittedin any form or by any means, electronic, mechanical, photocopying, recording, scanning,or otherwise, except as permitted under Section 107 or 108 of the 1976 United StatesCopyright Act, without either the prior written permission of the Publisher, or authorizationthrough payment of the appropriate per-copy fee to the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600, or on the web atwww.copyright.com. Requests to the Publisher for permission should be addressed to thePermissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030,(201) 748-6011, fax (201) 748-6008, or online at www.wiley.com/go/permissions.

Limit of Liability/Disclaimer of Warranty: While the publisher and the author have usedtheir best efforts in preparing this book, they make no representations or warranties withrespect to the accuracy or completeness of the contents of this book and specically disclaimany implied warranties of merchantability or tness for a particular purpose. No warrantymay be created or extended by sales representatives or written sales materials. The adviceand strategies contained herein may not be suitable for your situation. You should consult

with a professional where appropriate. Neither the publisher nor the author shall be liablefor any loss of prot or any other commercial damages, including but not limited to special,incidental, consequential, or other damages.

For general information about our other products and services, please contact our CustomerCare Department within the United States at (800) 762-2974, outside the United States at(317) 572-3993 or fax (317) 572-4002.

Wiley also publishes its books in a variety of electronic formats. Some content that appearsin print may not be available in electronic books. For more information about Wileyproducts, visit our web site at www.wiley.com.

Library of Congress Cataloging-in-Publication Data:

McGivney, William.Cost estimating manual for water treatment facilities/

William McGivney and Susumu Kawamura.p. cm.

Includes bibliographical references and index.ISBN-13: 978-0-471-72997-6 (cloth/CD: alk. paper)ISBN-10: 0-471-72997-3 (cloth/CD: alk. paper)

1. Water treatment plantsDesign and construction

EstimatesHandbooks, manuals, etc. I. Kawamura, Susumu. II. Title.TD434.M38 2008628.1 060681dc22 2008003737

Printed in the United States of America

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Contents

Preface xi

List of Illustrations xv

Chapter 1 Introduction to ConstructionCost Estimating 1

1.1 Cost Estimating Art or Science? 11.2 Structure of the Manual 11.3 Rules of Thumb for Good Estimates 21.4 Use of Historic Data 31.5 Adjusting the Numbers 3

Chapter 2 Water Treatment Processes 52.1 Basic Plant Design Philosophy 52.2 Brief Description of Basic Water Treatment 62.3 Basic Conventional Water Treatment Processes 82.4 Advanced Water Treatment Processes 12

Chapter 3 Solids Handling and Disposal 173.1 Solids Handling 173.2 Sludge Thickening 173.3 Sludge Dewatering and Drying 18

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Chapter 4 Construction Cost Estimatingat Predesign 19

4.1 Construction Cost Estimating 194.2 Classes and Types of Cost Estimates 204.3 Predesign Construction Cost Estimating 214.4 Denition of Terms 214.5 Estimating Methodology 244.6 Capital Improvement Costs 26

Chapter 5 Water Treatment PredesignConstruction Costs 29

5.1 Introduction 295.2 Treatment Process and Cost Estimating Parameters 305.3 Cost Curves 32

5.4 Estimating Process and Total Facilities Cost 325.5 Individual Treatment Process Cost Curves 32

5.5.1 Chlorine Storage and Feed from 150-lbto 1-ton Cylinders 32

5.5.2 Chlorine Storage Tank with Rail Delivery or Feed from Rail Car 36

5.5.3 Chlorine Direct Feed from Rail Car 375.5.4 Ozone Generation 375.5.5 Ozone Contact Chamber 395.5.6 Liquid Alum Feed 395.5.7 Dry Alum Feed 405.5.8 Polymer Feed 415.5.9 Lime Feed 42

5.5.10 Potassium Permanganate Feed (KMNO4) 425.5.11 Sulfuric Acid Feed 435.5.12 Sodium Hydroxide Feed 435.5.13 Ferric Chloride Feed 45

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5.5.14 Anhydrous Ammonia Feed 465.5.15 Aqua Ammonia Feed 465.5.16 Powdered Activated Carbon 475.5.17 Rapid Mix G 300 485.5.18 Rapid Mix G 600 495.5.19 Rapid Mix G 900 495.5.20 Flocculator G 20 505.5.21 Flocculator G 50 505.5.22 Flocculator G 80 525.5.23 Circular Clarier with 10-Ft Side Water Depth 525.5.24 Rectangular Clarier 535.5.25 Gravity Filter Structure 555.5.26 Filter Media Stratied Sand 575.5.27 Filter Media Dual Media 57

5.5.28 Filter Multi-Media 585.5.29 Filter Backwash Pumping 585.5.30 Surface Wash System 595.5.31 Air Scour Wash System 595.5.32 Wash Water Surge Basin 605.5.33 Filter Waste Wash Water Storage Tank 61

5.5.34 Clearwell Water Storage Below Ground 625.5.35 Finished Water Pumping TDH 100 Ft 635.5.36 Raw Water Pumping 645.5.37 Gravity Sludge Thickener 655.5.38 Sludge Dewatering Lagoons 665.5.39 Sand Drying Beds 68

5.5.40 Filter Press 695.5.41 Belt Filter Press 695.5.42 Centrifuge Facility 715.5.43 Administration, Laboratory, and

Maintenance Building 72

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5.6 Estimating Capital Costs 735.7 Estimating Capital Costs of a Conventional Water

Treatment Plant 755.7.1 Two-Stage Filtration Plant 755.7.2 Direct Filtration Plant 805.7.3 Conventional Filtration Plant 805.7.4 Dissolved Air Flotation Filtration Plant 815.7.5 Lime and Soda Ash Filtration Plant 81

5.7.6 Iron and Manganese Removal Plant 825.7.7 Micro Membrane Filtration Plant 835.7.8 Direct Filtration with Pre-ozone

Filtration Plant 845.7.9 Conventional Treatment with Ozonation

and GAC Filtration Plant 845.8 Estimating the Cost of Advanced Water

Treatment Plants 865.8.1 Reverse Osmosis (RO) Treatment Plant 885.8.2 Multiple-Effect Distillation (MED) Treatment

Plant 895.8.3 Mechanical Vapor Compression (MVC)

Treatment Plant 89

5.8.4 Multi-Stage Flash (MSF) DistillationTreatment Plant 90

5.8.5 Ultra-Filtration and Nano-Filtration 91

Chapter 6 Operation and Maintenance Cost Impacts 95

6.1 Annual Operating and Maintenance Cost 956.2 O&M Cost Curves 96

6.2.1a Two-Stage Filtration 966.2.1b Direct Filtration 976.2.1c Conventional Treatment 97

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6.2.2a Dissolved Air Flotation 986.2.2b Lime & Soda Ash Softening 986.2.2c Iron Manganese Removal 996.2.3a Micro Membrane Filtration 996.2.3b Direct Filtration with Pre-Ozonation 1006.2.3c Conventional Treatment with Ozonation

and GAC Filters 1006.3 Advanced Water Treatment Seawater

Desalination 1006.3.1 O&M Costs for Reverse Osmosis Treatment 1016.3.2 O&M Costs for Multi-Stage Flash 1016.3.3 O&M Costs for Multiple Effect Distillation

(MED) Treatment 1026.3.4 O&M Costs for Mechanical Vapor

Compression (MVC) Treatment 1026.3.5 O&M Costs for Ultra-Filtration and

Nano-Filtration 103

Chapter 7 Future Water Supply, Treatment and Distribution 105

Appendices 109Preface to the Appendices 111Appendix ADetailed Treatment Plant Cost Tables 113

A.1a Two-Stage Filtration Process 10 MGD 115A.1b Two-Stage Filtration Process 100 MGD 119A.2a Direct Filtration Process 10 MGD 123A.2b Direct Filtration Process 100 MGD 127A.3a Conventional Water Treatment Processes

10 MGD 131A.3b Conventional Water Treatment Processes

100 MGD 135

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A.4a Dissolved Air Flotation (DAF) asPretreatment Process 10 MGD 139

A.4b Dissolved Air Flotation (DAF) asPretreatment Process 100 MGD 143

A.5a Lime and Soda Ash Water Softening Process10 MGD 147

A.5b Lime and Soda Ash Water Softening Process100 MGD 151

A.6a Iron and Manganese Removal Process10 MGD 155

A.6b Iron and Manganese Removal Process100 MGD 159

A.7a Micro Membrane Filtration Process 10 MGD 163A.7b Micro Membrane Filtration Process

100 MGD 167

A.8a Direct Filtration with Pre-Ozonation10 MGD 171

A.8b Direct Filtration with Pre-Ozonation100 MGD 175

A.9a Conventional Treatment Process withOzonation and GAC Filters 10 MGD 179

A.9b Conventional Treatment Process withOzonation and GAC Filters 100 MGD 183

Appendix BTable B1Basis of Opinion of ProbableConstruction Cost 187Appendix CShorthand Conversion Table for Metric (SI) Conversions and Other Useful Factors 190

Glossary 191

Bibliography 197

Index 199

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Preface

For many years my coauthor, Susumu Kawamura, PhD, and I have beengood friends and colleagues in the business of designing and estimatingthe costs of water treatment plants, along with reservoirs, pipelines, andpumping stations. Susumu performs detailed designing with great preci-sion. My part has been the development of construction cost estimates forthe plants and facilities that civil engineers design with great precision.By this I mean that Susumu is paid to be precisely correct in designing aplant, while I am paid to estimate the future cost of transferring the de-sign to a physical plant. In short, he has to be right, and I just have to beclose. Of course, I mean this in the best possible way. Estimating is moreof an art than a science.

The design criteria and process selection for the complete plants isclosely aligned to the Susumus book, in its second edition Integrated De-sign and Operation of Water Treatment Facilities (Wiley, 2000). We have

talked about writing this manual for a number of years, and although ithas taken over twice as long as we planned, it passes the estimators pri-mary test of being close enough for government work.

This manual is specically for the estimating of construction costsfor water treatment plants at the preliminary design level. In order toprovide you with a manual that you can use with some condence, wehave compiled the results of our experience and that of many othersinto a fairly large database of construction costs for separate water

treatment processes. The actual historic costs were analyzed, mas-saged, and separated into component parts representing constructedelements. These primary constructed elements include: civil site work,structures, architectural, process equipment, mechanical piping and valves, electrical, and instrumentation. And each treatment process

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has more or less the same relative percentage of these elements over atleast one order of magnitude of costs, say between $1.0 million and

$10.0 million.Once the cost of the treatment processes is established, they can easily

be combined into a complete water treatment plant cost estimate. Themanual identies 43 individual processes or facilities for a normalwater treatment plant. We have selected nine types of water treatmentplants and augmented them with ve additional types of advanced watertreatment plants. The 43 treatment processes are listed in order foreach type of treatment plant along with the number of unit modules and

the quantity for the process parameter. The equation form is used to cal-culate the dollar cost of the complete process, which is summed to a sub-total to which certain mark-ups or allowances are then added to estimatethe total direct cost of construction for the plant. To estimate the totalraw capital cost, additional allowances are then added for the non-construction or soft costs. Sample tables for each type of plant are in-cluded for 10 mgd and 100 mgd product water ow rates.

The secondary data is adjusted using construction cost indexes bring-

ing them to September 2007 in Los Angeles, California. We used the Engineering News Record (ENR) Construction Cost Index which is pub-lished and distributed monthly by McGraw-Hill. This index is annotatedon each cost curve in this manual (ENR-CCI 8889).

We have also compiled operations and maintenance costs for thesesame plants over the same range of product water ow. The O&M costsare similarly set for the current period of September 2007 for labor,power, and chemical usage, as well as maintenance of the facility at anaverage cost per year.

This manual comes with the complete electronic les in Microsoft Ex-cel on a single compact disk (CD). There are instructions on the CD in theuse of the tables for estimating treatment process and total plant costs.The primary data used to generate the curves and establish equations forcalculating the costs are not is not part of the manual or CD. The les arenot protected nor are they warranted free of error.

We believe this manual will provide you with the basis to estimate con-struction costs at the preliminary design level for water treatment proc-esses and complete plants. If you compile actual construction costs withinyour own experience and wish to share them with the authors, we willadd them to the database and include the results in the second edition. All condences will be preserved as they are in regard to the data in this

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manual. The authors have committed to a second manual for wastewatertreatment. So if you nd this manual useful, let us know.

Susumu Kawamura and William McGivney,Christmas 2007

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List of Illustrations

2.3 Overhead View of Water Treatment Plant2.3.1a Two-Stage Filtration Process2.3.1b Direct Filtration Process2.3.1c Conventional Treatment Process2.4.1a Dissolved Air Flotation (DAF) as Pretreatment Process2.4.1b Lime and Soda Ash Water Softening Process2.4.1c Typical Iron and Manganese Removal Process2.4.2a Micro Membrane Filtration Process2.4.2b Direct Filtration Process with Pre-Ozonation2.4.2c Conventional Treatment Process with Ozonation and GAC

Filters5.5.1a One-Ton Chlorine Cylinders and Chlorine Feeder (Photo)5.5.1b One-Ton Chlorine Cylinders and Chlorine Feeder

5.5.2 Chlorine Storage and Feed On-Site Storage Tank with

Rail Delivery5.5.3 Direct Chlorine Feed from Railcar5.5.4a Ozone Generator (Photo)5.5.4b Liquid Oxygen Storage Tank and Evaporators (Photo)5.5.4c Ozone Generation in Pound per Day5.5.5 Ozone Contact Chamber Over/Under Bafes5.5.6 Liquid Alum Feed

5.5.7a Alum-Polymer Storage Tank (Photo)

5.5.7b Dry Alum Feed5.5.8 Polymer Feed (Cationic)5.5.9 Lime Feed

5.5.10 Potassium Permanganate Feed5.5.11 Sulfuric Acid Feed 93% Solution

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5.5.12a Sodium Hydroxide Storage (Photo)5.5.12b Sodium Hydroxide Feed

5.5.13 Ferric Chloride Feed 42% Solution5.5.14 Anhydrous Ammonia Feed5.5.15 Aqua Ammonia Feed5.5.16 Powdered Activated Carbon

5.5.17a Flocculation and Rectangular Clarier Basins (Photo)5.5.17b Rapid Mix G 300

5.5.18 Rapid Mix G 6005.5.19 Rapid Mix G 900

5.5.20 Flocculator G 20 Ten Minutes5.5.21a Vertical Shaft Flocculator with Mixing Blades (Photo)5.5.21b Horizontal Shaft Flocculator with Paddle-Type Blades (Photo)5.5.21c Flocculator G 50 Ten Minutes5.5.22 Flocculator G 80 Ten Minutes5.5.23 Circular (10-Ft Side Water Depth)

5.5.24a Sedimentation Tank (Photo)5.5.24b Center-Pivoted Rotating Rake Sludge Collector in

Sedimentation Tank (Photo)5.5.24c Rectangular Clarier5.5.25a Filter Pipe Gallery of the F. E. Weymouth Filtration Plant of

MWD of Southern California (Photo)5.5.25b Gravity Filter Structure by Sq. Ft. Filter Area5.5.26a Filter Cell, Grandular Media Gravity Filter (Photo)5.5.26b Filtration Media-Stratied Sand (Old Design)

5.5.27 Filter Media Dual Media5.5.28 Filter Multi-Media5.5.29 Filter Backwash Pumping5.5.30 Surface Wash System Hydraulic5.5.31 Air Scour Wash5.5.32 Wash Water Surge Basin (Holding Tank)

5.5.33a Filter Waste Wash Water Storage Tank (Photo)5.5.33b Filter Waste Wash Water Storage Tank (Waste Wash Water)

5.5.34 Clear Water Storage (Buried Million Gallons)5.5.35a Finished Water Pumping Station (Centrifugal Pumps) (Photo)5.5.35b Finished Water Pumping (TDH 100 Ft)5.5.36a Six Vertical Pumps in Front of a Building (Photo)5.5.36b Raw Water Pumping5.5.37a Gravity Sludge Thickener (Photo)

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5.5.37b Gravity Sludge Thickeners5.5.38a View of Sludge Dewatering Lagoons (Photo)

5.5.38b View of Sludge Dewatering Lagoon with Dried Sludge (Photo)5.5.38c Sludge Dewatering Lagoons5.5.39a View of Sand Drying Beds (Photo)5.5.39b Sand Drying Beds

5.5.40 Filter Press5.5.41a View of Filter Belt Press (Photo)5.5.41b Filter Belt Press5.5.42a Centrifuge Facility (Photo)

5.5.42b Centrifuge Facility5.5.43 Administration, Laboratory, and Maintenance Buildings

5.6.1 Conventional Treatment Process5.7.1 Two-Stage Filtration5.7.2 Direct Filtration

5.7.3a New Mohawk Water Treatment Plant., Tulsa Oklahoma (Photo)5.7.3b Conventional Filtration

5.7.4 Dissolved Air Filtration

5.7.5 Lime and Soda Ash Filtration5.7.6 Iron Manganese Removal

5.7.7a Micro-Filtration Plant Designed with a Rectangular Tank withSix Compartments (Photo)

5.7.7b Micro Membrane Filtration5.7.8 Direct Filtration with Pre-Ozone Construction Cost5.7.9 Conventional Treatment with Ozonation & GAC Filters

Construction Cost5.8a Ion Exchange Demineralization Unit System (Photo)5.8b Total Project Construction Cost Comparison

5.8.1 Reverse Osmosis (RO) Construction Cost5.8.2 MED Construction Cost5.8.3 MVC Construction Cost5.8.4 MSF Construction Cost

5.8.5a Membrane Filters (Photo)5.8.5b Membrane Filters Fiber Details (Photo)5.8.5c UF Construction Cost6.2.1a O&M Costs for Two-Stage Filtration6.2.1b O&M Costs for Direct Filtration6.2.1c O&M Costs for Conventional Treatment6.2.2a O&M Costs for Dissolved Air Flotation

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6.2.2b O&M Costs for Lime and Soda Ash6.2.2c O&M Costs for Iron Manganese Removal

6.2.3a O&M Costs for Micro Membrane Filtration6.2.3b O&M Costs for Direction Filtration with Pre-Ozonation6.2.3c O&M Costs for Conventional Treatment with Ozonation

and GAC Filters6.3.1 O&M Costs for Reverse Osmosis6.3.2 O&M Costs for Multi-Stage Flash Treatment6.3.3 O&M Costs for Multiple Effect Distillation (MED) Treatment6.3.4 O&M Costs for Mechanical Vapor Compression (MVC)

Treatment6.3.5 O&M Costs for UF NA Filtration

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Chapter 1

Introduction to ConstructionCost Estimating

1.1 COST ESTIMATING ART OR SCIENCE?

Is cost estimating an art or a science? My usual response to this questionis that cost estimating is both, but more art than science. The science part

is made up of engineering and statistics. And the art of estimating isbased more on economics and subjective modeling based, and relying onthe estimators experience and knowledge of construction.

Good accurate cost estimating has been the mainstay of human devel-opment for at least 8,000 years. Every great empire sustained growth anddevelopment because they could afford it. And they could afford this eco-nomic development because, among other things, they were good at esti-mating costs in advance of expenditures. Many other groups suffered

through a trial-and-error method of achieving sustained economic devel-opment for myriad reasons. But one reason could be that they were verypoor cost estimators. This may be a gross oversimplication, but good costestimating is better than bad.

1.2 STRUCTURE OF THE MANUAL

This manual is not meant to be a rigorous economic analysis or scholarlyinvestigation. It is an outline for preparing good cost estimates for watertreatment plants. In this manual the reader will nd; basic water treat-ment plant design philosophy and process schematics; predesign cost es-timating methods and procedures; process parameters and their costcurves; and total plant costs, including tables and equation functions; as

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well as capital and operations and maintenance cost for each type of com-plete water treatment plant.

The estimating methodology is an amalgam of the best practices of costestimating and the personal experience of the authors. We have freelyused studies and public documents provided by governments and our ownhistorical project data. These tools have provided us with a sound way of developing cost estimates based on specic parameters for individualprocesses of conventional as well as advanced water treatment plants.

1.3 RULES OF THUMB FOR GOOD ESTIMATES

In the busy life of an engineer or manager, there is rarely enough time todevelop a comprehensive detailed cost estimate. So, one may look aroundfor someone not so busy and free to take on the assignment. They maygive the assignment to the newest addition to their staff. If this personhas enough experience, the estimate will be good. If they have little expe-rience, the estimate will be very poor. And there will be negative reper-cussions to the budget for design and construction. Cost overruns will

run amok, reputations will suffer, and the owner will be very unhappy.

So, the rst rule of thumb is to assign the cost estimating to thebest-qualied staff person and give them a copy of this manual tohelp guide them through the effort.The second rule of thumb is to resist the temptation to assumethat cost estimates have the same precision as engineering tasks.If they did, they would not be called estimates. Many predesignestimates are carried out to the dollar and much is made of ex-pected accuracy. At this level of estimate a line item estimated tothe nearest $10,000 is a reasonable level of accuracy.The third rule of thumb is complete the design philosophy and de-sign parameters before estimating the costs. Time is better spentdeveloping solid design parameters such as the detention time, volume of process vessels, and redundancy of process units thatwill make operation and maintenance of the plant possible.Rule of thumb number four is to assign an experienced person toreview the estimate. This is obvious on the face of it, but the esti-mate is usually the last thing to develop when the design budget isexhausted and there is only one day before the report is due.The fth and nal rule of thumb is to check the math.

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1.4 USE OF HISTORIC DATA

All cost estimators and many engineers and managers keep historic costsin their lower-left desk drawer. This information is a gold mine to theirstaff and organization. Once adjusted for appropriate indices and level of detail, this data could be added to the cost curves in this book and used toimprove the in-house capabilities of the estimator, engineer, manager,and organization. The tables and cost curves contain the formula used toget the best t for the cost data behind the curves in this manual.

If your experience is the same as the authors, you will nd that thereappears to be a great variation in data and results. There are many rootcauses for these variations. Some are the results statistical anomalies;others, economic disparities; yet others, poor record keeping and adjust-ments. Even with the original, primary data, we found coefcients of colinearity (r-squared) in the neighborhood of 0.60 for the total cost of aconventional water treatment plant. And got r-squared(s) of 0.35 forpumping stations. In summary, do not expect precision, but constantlytest your assumptions, recheck the math, and review the work of others.

1.5 ADJUSTING THE NUMBERS

Historic costs have a way of remaining constant. They represent the ac-tual price of goods and services at some time in the past. They can be adjusted to another time or place on the basis of a cost index published byeither the government or a private entity that is generally accepted bythe industry or constituency it represents. It is important that the esti-

mator select the most reliable index and apply that index to the historiccost to compare it to other costs, either actual or estimated. Once adjusted, the resulting cost is no longer considered primary data.

Adjusting actual costs from some time in the past to the current periodpresumes that the goods and services that made up historic cost havenot changed and the costs for all components have changed in exactlythe same way. Making this adjustment can introduce inaccuraciesinto the estimate. Adjusting the actual cost from place to place eitheracross the country or from country to country is even riskier. And makingboth types of adjustments can eliminate any reasonable expectation of accuracy.

Our recommendation is to make at least three separate estimates of the cost using different means and assumptions. The cost curves and

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tables in this manual are one way to go about the estimating process.Getting input from someone of greater experience is the second. And us-

ing actual costs from published documents as comparisons could be thethird. In this way the estimator is able to plot a triangle of points and testthe individual process or complete treatment plant cost model forreasonableness.

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Chapter 2

Water Treatment Processes

2.1 BASIC PLANT DESIGN PHILOSOPHY

Construction cost estimating at the preliminary design phase of a projectis dependent on the basic design scheme, including sketches of the proj-ect. A properly and clearly prepared design philosophy is essential for thesuccess of the design and construction of all treatment facilities. The

well-prepared preliminary design construction cost estimate will formthe basis of an accurate capital projects budget. This type of cost estimateis based on experience and intuition rather than the more rigorous de-tailed engineers estimate.

Following a half-century of water and wastewater treatment design,construction and plant operational experience a pattern of successful de-sign development has become clear. There are ten basic rules or com-mandments for a successful design project.

The Ten Commandments for design project are as follows:

1. You shall make a careful analysis and evaluation of the qualityof both raw and required nished waters.

2. You shall undertake a through evaluation of local conditions.3. The treatment system developed shall be simple, reliable, effec-

tive, and consist of proven treatment processes.4. The system considered shall be reasonably conservative and

cost-effective.5. You shall apply the best knowledge and skill available for the

design.6. The system shall be easy to build and constructible within a rea-

sonable length of time.

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7. The system shall be easy to operate with maximum operationalexibility and with minimum operation and maintenance costs.

8. The facilities shall be aesthetically pleasing with no adverse ef-fect on the environment.

9. Design engineers shall perform services only in the area of theircompetence. Get help from qualied experts in areas outsideyour expertise.

10. You shall respect and owners knowledge and experience and in-corporate his wish list of additional features if they are withinthe established budget.

2.2 BRIEF DESCRIPTION OF BASIC WATER TREATMENT

Early water treatment systems were simple batch operations designedfor individual households. These processes included boiling, simple ltra-tion, and coagulation and ltration utilizing naturally available inor-ganic or organic coagulants. However, from the seventeenth century

onward, it was necessary to create facilities capable of treating largequantities of water to supply larger human settlements. The treatmentof water based on scientic principles began in Europe around the mid-1800s. During this time, water treatment professionals in Englandundertook the elimination of water-borne diseases such as typhoid andcholera.

The application of chlorine to potable water supply systems in Eng-land, during the 1850s, followed the scientic validation of germ theory.

However, it soon became evident that chlorination was ineffective whenapplied to cloudy water. This gave rise to the process of slow sand ltra-tion (0.05 gpm/sf or 0.125 m/hr lter rate), which removed suspended sol-ids before the application of chlorine. This rst era of water treatmentwas control of pathogenic bacteria by chlorination preceded by slow sandltration.

During the late nineteenth century, the Louisville Water Company inKentucky began pretreating raw water with alum coagulation followedby clarication and the use of rapid sand lters (2 gpm/sf or 5 m/hr lterrate). This new process was urgently needed. A signicant increase inpopulation and rapid industrial growth placed a demand on the watersystem that the slow sand lters could not meet. This development wasthe beginning of the water treatment plants of today.

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Drinking water quality standards were relaxed until the middle of thetwentieth century. Only minor changes to the basic conventional treat-

ment processes occurred until the late 1960s. The object of the watertreatment in this period was to produce sufcient amount of water safefrom pathogenic bacteria. Water treatment engineers, from late 1960s to1970s, concentrated their effort on designing the lowest-cost treatmentsystem to produce safe drinking water. High rate ltration and highhydraulic loading for a sedimentation basin with tube settler or plate set-tler modules and the use of ozone as an advanced treatment process havebecome popular since the mid-1990s.

The beginning of modern water treatment design started after the Sec-ond World War. High-technology industries ourished in the postwaryears in industrialized nations such as United States. As a result, largequantities of untreated synthetic industrial wastes were discharged intonearby water courses, the oceans, or the atmosphere, or dumped into andonto the land. Consequently, serious global environmental pollution re-sulted in more stringent drinking water quality standards, and new advanced treatment processes were urgently needed.

During the early 1970s, the Environmental Protection Agency (EPA)was established and the Safe Drinking Water Act (1974) and its amend-ment (1986), subsequently passed by the U.S. Congress, set stringentdrinking water quality standards.

The motto of water treatment had now become make large quantitiesof good quality water.

The issues after mid-1990s are control of protozoa, especially Crypto-sporidium and Giradia ; control of disinfection process byproducts as well

as arsenic; disposal of treatment residues; and the supplying of noncorro-sive water. Recent treatment issues coming up are treatment of xenobiot-ics, which are related to small amount of pharmaceutical and drugresiduals in source of waters, as well as control of taste and odor.

Today, we have advanced water treatment technology and thousandsof miles of water distribution systems. However, the eld of water treat-ment faces new problems such as a limited source (less than 3% of wateron earth) of easily treatable water for potable water, heavy industrial andhuman activities, and the population explosion.

The project development and project delivery procedure in recentyears have been shifting away from traditional ways. The old way washaving a single group of civil engineers handle the majority of designwork, supported by mechanical, electrical, and architectural engineers.

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However, the regulatory requirements and complexity of the projectsnow require a multidisiplinary design team.

The traditional designing of water treatment plants includes a profes-sional engineering rm or owners in-house staff who prepares specica-tions and drawings. Sealed bids are received and contractor(s) selectedbased on the lowest responsible bidder. The design team performs con-struction management services until the facility is completed and com-missioned. After commissioning by the design team and the owner, theybegin operating the facilities.

In early 1990s, changes were taking place in traditional project deliv-

ery. The idea was the incorporation of design, construction, and operationof the facilities with a new nancial/political arrangement called privati-zation. Privatization as its name implies is turning over all or part of thefacility development and operation to a privately held entity. Theseschemes include; design-build-operate (DBO), design build-maintain(DBM), public-private-partnerships (PPPs), and long-term contractoperation.

The recent popularity of privatization for domestic water utilities is

the result of internal and external competition. Contributing factors in-clude increased regulatory requirements for upgrading existing as wellas new plants, negative consequences from different levels of mainte-nance, public resistance to rate increases, and the nancial crisis facedby many public utilities. However, privatization projects also have nega-tive aspects, including less than optimum safety as well as reliability forplant and a tendency toward operational inexibility. These negative is-sues are mainly due to attempts to improve protability, reduce costs by

rapid facility construction, and keep operational costs at a minimum.This is also true for wastewater treatment facilities.

2.3 BASIC CONVENTIONAL WATER TREATMENT PROCESSES

Figure 2.3 above shows the relative size and layout of the treatment proc-esses of a conventional water treatment plant. The basic conventionaltreatment train for surface water treatment consists of coagulation withrapid mixing followed by occulation, sedimentation, granular media l-tration with nal disinfection by chlorine. This treatment process train isa standard requirement for municipal water treatment by the Depart-ment of Health Services (DHS) of each state as well as the Ten StateStandards, which apply to the ten states in the Midwest Region and the



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East Coast Region of United States. However, the basic treatment trainscan be modied, dependent upon the quality of raw water and the n-ished water quality requirements.

For instance, where the raw water quality is good, sedimentation pro-cess can be excluded from the basic treatment train. This process system

is Direct Filtration. In some instances, both regular occulation and sedi-mentation process are replaced with coarse media occulation/roughinglter process in front of regular granular media ltration. In other cases,the ltration process is preceded by ash mixing of a coagulant. This is theIn-Line Filtration or Contact Filtration process. However, these modiedconventional treatment processes must have a variance permit from thegoverning regulatory agencies before design and facility construction.

If surface waters have high levels of turbidity, hardness, total organiccarbon (TOC), microorganisms including algae, taste and odor, and otherunwanted substances, then certain additional process or modications of the conventional process and plant operation will be necessary. Flashmixing of coagulant at the head of plant is essential and the water-jet dif-fusion type is the most effective system. The current occulation basin is

Figure 2.3 Overhead View of Water Treatment Plant

Basic Conventional Water Treatment Processes 9


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a rectangular basin and vertical shaft mechanical occulators with hy-drofoil type mixing blades. An earlier design included a horizontal shaft

with paddle type mixing wheel. However, an improved bafed channeldesign (helicoidal ow pattern) is currently in use. Common sedimenta-tion tanks are rectangular horizontal ow type with or without high ratesettler modules such as tube settler or plate settler modules. A mechani-cal sludge collection system is a part of the sedimentation system. A fewproprietary units use a combination of occulation and claricationprocesses.

The common ltration system consists of gravity lters with granular

media beds. The anthracite and sand dual-media bed has been a standardlter bed since the 1980s. Surface wash systems for 6 00 to 18 00 depth of beddepending on the system used, as well as air scouring wash systems thatscour the entire lter bed, with a backwash and lter-to-waste provisionhave become common. The clearwell usually provides at least 4 hours of nish water storage capacity. The clearwell should be bafed to minimizeow short-circuiting, and it must be covered.

Chemical storage and feed system are an important part of the treat-

ment plant. The sludge handling and disposal is an essential facility of water treatment plant. These items are discussed later in this chapter. A few water treatment plants require intermediate pumping. Intermediatepumping facilities can become expensive when required by hydraulicanalysis. Plant security systems are critical facilities due to the potentialfor acts of terrorism.

Basic ground water treatment uses granular media ltration processfollowed by chlorination. If the water quality of the source is exception-

ally good, only disinfection by chlorine may be required. However, an oxi-dation process may be needed when high levels of soluble iron,manganese, and other substances exist in the source water.

The granular ltration process is always included in the basic treat-ment process because it is the main barrier to keep suspended matter,including microorganisms, from passing into the potable water supply.Over the last forty years, lter design has become either dual-media bedor coarse media deep bed with or without a thin ne sand layer at thebottom. The ltration rate for these lters is usually limited to 6 gpm/sf (15 m/h) by regulatory agencies. However, several water treatmentplants on the West Coast are achieving a ow rate of 8 to13 gpm/sf (20 to32.5 m/h) with pre-ozonation under variance permits issued by the Cali-fornia Department of Health Services. Figures 2.3.1a, 2.3.1b, and 2.3.1c



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A l k a l

i ( O p t

i o n a l )

( O p t

i o n a

l )

P A C

P o l y m e r

C o r r o s i o n

C o n

t r o l

C a t

i o n i c

P o l y m e r

A l u m

/ F e r r i c

Gravel BedFiltration

Granular BedFiltration

C t Tank

ClearwellFlash Mix

( O p t

i o n a

l )

N H

3

Holding TankClarifier

ThickenerSludge

Wash Waste

F i l t e r t o

W a s t e

P o l y m e r

C l 2

C l 2

Figure 2.3.1a Two-Stage Filtration Process

P o l y m e r

C o r r o s i o n

C o n

t r o l

C a t

i o n i c

P o l y m e r

A l u m

/ F e r r

i c

FlocculationFlash Mix Granular BedFiltration

C t Tank

Clearwell

C l 2 N

H 3

( O p t

i o n a

l )

Holding Tank

Thickener

Clarifier

P o l y m e r

Sludge

Filter to Waste

W a s h w a s

t e

C l 2 o r

P A C ( O p t

i o n a

l )

O p t

i o n a

l

Figure 2.3.1b Direct Filtration Process

Basic Conventional Water Treatment Processes 11


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show three diagrams of a basic conventional treatment processes withslightly different chemical application systems.

2.4 ADVANCED WATER TREATMENT PROCESSES

As described earlier the EPA has promulgated the Surface Water Treat-ment Rule (1989) and the Interim Enhanced Surface Water Treatment

Rule (1998) in order to provide not only safe but also the best qualitydrinking water for the public. The major elements of these rules includeremoval of total organic carbon (TOC) from raw water to certain targetedlevels in order to control the disinfection byproducts (DBPs) and inactiva-tion or removal of Cryptosporidium oocysts , which regular chlorinationcannot achieve. There are many other Maximum Contaminant Levels(MCL) for drinking water quality standards for inorganic and organicchemicals, microbiological contaminants, disinfectants, radionuclides,

turbidity, and other conditions.Since the basic conventional water treatment processes cannot achieve

these requirements unless the source of water is exceptionally good, sev-eral new treatment process technologies have been developed and imple-mented in recent years.

A l k a l

i

C l 2 o r

P A C ( O p t

i o n a

l )

P o l y m e r

( N o t

f o r R a p

i d S a n

d F i l t e r )

C o r r o s i o n

C o n

t r o l

C a t

i o n i c

P o l y m e r

A l u m

/ F e r r i c

K M n O

4

FlocculationFlash Mix Granular BedFiltration

C t Tank

Clearwell

C l 2 N

H 3

( O p t

i o n a

l )

Holding Tank

Thickener

Clarifier O p t

i o n a

l

W a s

t e

W a s

h

C l 2

A n i o n

i c P o l y m e r

Sedimentation

F l u o r i

d e

Sludge

Recycle

(Micro Filter as Alt.)

Filter to Waste

Figure 2.3.1c Conventional Treatment Process



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Ozonation, granular activated carbon adsorption, high-speed micro-sand settling process, high-rate dissolved air otation (DAF) process,

magnetic exchange (MIEX) process, new type of UV disinfection process,and advanced membrane ltration process (MF, UF, NF, and RO) areconsidered as major advanced water treatment processes of in late twen-tieth century to early twenty-rst century. These new treatment proc-esses are used in conjunction with the basic conventional treatmentprocess described earlier.

Figures 2.4.1a, 2.4.1b, and 2.4.1c illustrate three examples of advancedwater treatment plants.

L i m e

P o l y m e r

C a t

i o n i c

P o l y m e r

A l u m

/ F e r r i c

FlocculationFlash Mix

N a O

H

FiltrationC t Tank Clearwell

N H

3 ( O p t

i o n a

l )

A i r S a t u r a

t i o n

T a n

k

Holding TankClarifier

Sludge

DAF

Filter to WasteDewater

W a s

h

W a s

t e

O p t

i o n a

l

C l 2

C l 2

Figure 2.4.1a Dissolved Air Floatation (DAF) as Pretreatment Process

L i m e

P o l y m e r

P o l y m e r

( O p t

i o n )

SolidsContactClarifier

Flash Mix

C o r r o s i o n

I n h i b i t o r

Filtration Clearwell

C l 2 N

H 3

( O p t

i o n a

l )

C O

2 G a s

Holding Tank

Clarifier

Sludge

CO 2 ContactTank

Filter to Waste

Dewater

S o d a A s h

F e r r o u s

S u l f a t e

Clarifier

O p t

i o n a l

W a s

t e

W a s

h

Figure 2.4.1b Lime and Soda Ash Water Softening Process

Advanced Water Treatment Processes 13


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These advanced treatment processes are also being incorporated intowastewater treatment design as advanced treatment processes for waterreuse purposes. Desalination and water reuse are growing water treat-

ment technologies because of a growing shortage or contamination of rawwater in many regions of the world. The as yet unknown consequencesresulting from global warming, whatever the cause, may rapidly increasethe need for water reuse. Figures 2.4.2a, 2.4.2b, and 2.4.2c are examplesof additional, advanced water treatment plant design.

C o r r o s i o n

C o n

t r o l

Micro Screen Micro FilterC t Tank

Clearwell

C l 2 N

H 3

( O p t

i o n a l

)

Holding Tank Holding Tank or Sewer (Option)WashWaste

ChemicalCleaningWaste

DischargeTank Truck (Recycle)

Figure 2.4.2a Micro Membrane Filtration Process

L i m e

P o l y m e r

C l 2

Aeration

C o r r o s i o n

I n h i b i t o r

Filtration Clearwell

C O

2 G a s

Holding Tank

Sludge

Contact Tank

Filter to Waste

Dewater

Clarifier

C l 2

K M n O 4

Water Well

W a s

t e

W a s

h

O p t

i o n a

l

Figure 2.4.1c Typical Iron and Manganese Removal Process



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In the following chapters, preliminary construction costs will be devel-oped for each of these nine scenarios, with a design plant ow of 10 MGDand 100 MGD. The data used for the cost curves was collected over manyyears from multiple sources.

C o r r o s i o n

C o n

t r o l

C a t

i o n i c

P o l y m e r

A l u m

/ F e r r i c

FlocculationFlashMix

BAF withGAC Bed

C t Tank

Clearwell

N H

3 ( O p t i o n a

l )

Holding Tank

Thickener

Clarifier

P o l y m e r

P o l y m e r

Sludge

Filter to Waste

Wash Waste

C l 2 o r

P A C ( O p t

i o n a

l )

Ozonation

H 2 O 2

( O p t

i o n a l

)

O 3

O p t

i o n a

l U V ( O p t

i o n a

l )

C l 2

Figure 2.4.2b Direct Filtration Process with Pre-Ozonation

A l k a l

i

C o r r o s i o n

C o n

t r o l

A l u m

/ F e r r i c

A c i

d ( O p t

i o n a

l )

FlocculationFlashMix

BAF withGAC Bed

C t Tank

Clearwell

N H

3 ( O p t

i o n a

l )

Holding Tank

Thickener

Clarifier

P o l y m e r

A n i o n

i c P o l y m e r

Clarifier

F l u o r i

d e

Sludge

Recycle

(Micro Filter as Alt.)

Filter to Waste

A n i o n

i c P o l y m e r

Pre-Ozone

C a t

i o n i c

P o l y m e r

Pre-FilterOzonation

W a s

h

W a s

t e

O p t

i o n a

l

H 2

O 2

H 2

O 2

( O p t i o n a l )

O 3

H 2

O 2 O

3 ( O p t i o n a l )

H 2

O 2

( O p t i o n a l )

C l 2

C l 2

Figure 2.4.2c Conventional Treatment Process with Ozonation and GAC Filters

Advanced Water Treatment Processes 15


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Chapter 3

Solids Handling and Disposal

3.1 SOLIDS HANDLING

Solids handling begins with thickening the collected sludge in order toincrease the solids content from 0.5% produced in the clariers to any-where from 3% to as much as 70% solids. The sludge removal process will

waste less than 0.5% of the plant ow unless the sludge is dewatered andthe liquid returned to the head of the plant. This thickening is aided bythe addition of a polymer to the collected sludge increasing the percent-age of solids in the sludge liquor. The sludge is then processed eitherthrough gravity thickening or by mechanical thickening, increasing thepercentage of solids. The minimum percentage of solids allowed at mostdisposal sites is dictated by a combination of federal and local regulations.

3.2 SLUDGE THICKENINGThere are several means to handle this task, including sludge lagoons,gravity thickening tanks, and dissolved air otation tanks. Each processwill produce a different percentage of solids and have different construc-tion and operations costs. The construction costs of these processes areamong those detailed in Chapter 5 of this manual.

It may be possible to transfer the cost of solids handling simply by add-

ing the sludge to the local sewer connection. The local sewage disposalutility can provide the fee structure to be used along with a meter at-tached to the sewer lateral that will keep track of the discharge. For asmall water treatment plant this transfer fee will usually be lower thanthe capital investment and O&M costs of a solids facility. Some existing

17



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water treatment plants utility use existing sludge lagoons where theliquid seeps into the ground leaving the solids at the surface. Lagoons

are by far the cheapest from both a construction and operating cost. If there is sufcient land available and this type of system is permitted, it isa very cost-effective solution.

To avoid compromising the ground water aquifers the ltrate must becaptured and not allowed to seep into the ground. Sand drying beds aredesigned with liners, drains, and sumps to catch the ltrate. They alsoprovide a higher percentage of solids and allow the capture of the ltrateto be disposed of in the sewer.

Gravity thickeners and dissolved air otation tank construction costsare necessary when land is scarce, particularly when an existing plant isgoing through phased expansion. These processes are commonly used asthe rst stage of solids handling at water treatment plants.

3.3 SLUDGE DEWATERING AND DRYING

Once the solids pass through a thickening process they are further proc-

essed to remove additional water and increase the percentage of solids by volume. With the exception of sand drying beds all other drying methodsrequire mechanical means and signicant investment. Mechanical equip-ment for dewatering and drying include; solid-bowl centrifuges, belt-lterpresses, recessed plate lter presses, vacuum lters, rotary sludge dryer,and incinerator. Centrifuges and lter presses are commonly used andare among the processes identied in Chapter 5. Vacuum lters and ro-tary sludge dryers with incinerators are not addressed here.

18 SOLIDS HANDLING AND DISPOSAL


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Chapter 4

Construction Cost Estimating at Predesign

4.1 CONSTRUCTION COST ESTIMATING

A basic element of the design process is facilities construction cost esti-mating. Establishing a reasonable construction budget during the pre-design work will add direction and integrity to the design process. The

predesign will typically consider multiple process alternatives. Each typeof process will have a different construction cost. The owner must takeinto account interest rates, administrative/legal costs, design engineer-ing costs, land use, and local political considerations. Invariably the issueof design engineering and engineering support during construction willbe carefully reviewed and negotiated in part on the integrity of the pre-design process. Each of the process alternatives will also have unique op-eration and maintenance costs dependent on the requirement for labor,

energy, chemical and other consumables.Since design development is a dynamic process, it is very importantthat the estimated cost of the project be periodically checked against thecapital budget. Therefore, a series of cost estimates are prepared andcompared to the previous ones. These estimates should be as detailed aspossible, based upon the increasing level of information available. It isrecommended that written guidelines for each of type of construction costbe developed. An initial set of guidelines is offered below.

The Association for the Advancement of Cost Engineering, (AACEi)has established a comprehensive set of standards and guidelines for thispurpose. It is imperative that the entire design team, and all projectstakeholders, be kept fully informed, and be held responsible for theirparticipation in the establishment of budgets for design, and ultimately

19



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for the nal construction cost of every project. A project-centered ap-proach coupled with an effective, open channel of communication will

prevent unfortunate surprises to escalating or uncontrolled costs. It willfurther help ensure a professional engineering environment, directed atproblem solving, rather than one deteriorating into reactionary, or adver-sarial, relationships between members of the design team.

More specically, these guidelines establish the criteria, format, us-age, accuracy, and limitations of the various types of construction costestimates. To accomplish this task it is necessary to implement the fol-lowing criteria:

Dene the type of cost estimates and a detailed narrative calledthe Basis of Estimate to be prepared during the various phases of a projects development. Within these denitions would be the ex-pected accuracy of the cost estimate as well as limitations on its value and use. Dene the responsibility for the preparation and review of thesecost estimates.

Dene the cost estimating method relative to the construction andcapital improvement costs of the facilities. Develop the procedures to prepare and review the cost estimateson a uniform basis.

Once developed, these standards can be implemented on all designprojects and capital improvement programs. A consistently applied set of guidelines and growing project database as well as local unit pricing datacan provide a more accurate, less problematic cost estimate.

4.2 CLASSES AND TYPES OF COST ESTIMATES

Construction cost estimates are categorized into ve classes: 5, 4, 3, 2,and 1, in reverse numerical order by level of detail available dependingon their use. Each cost estimate should include a Basis of the Estimatenarrative as discussed below. As the level of detail required in performingthe cost estimate increases, the labor and experience of the estimatingstaff required to complete the material take-off and pricing rises signi-cantly. The estimating accuracy discussed below, pertinent to each classof cost estimate, is not meant to represent absolute limits or guarantees,but instead to establish a most likely range within which the nal projectconstruction cost will fall.

20 CONSTRUCTION COST ESTIMATING AT PREDESIGN


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4.3 PREDESIGN CONSTRUCTION COST ESTIMATING

The rst of these is the predesign cost estimate . The intent of this manual,given the lack of design detail, is to assist in the establishment a realisticestimate of the cost and time components, based on a combination of unitcosts and process parameters. This cost estimate is typically dened as aClass 5 cost estimate with an expected accuracy of 50% to 30% of theaverage bid price for construction. This type of construction cost estimateis generally used for the development of capital improvement plans, mas-ter plans, and feasibility studies. Predesign construction costs are usefulin the comparisons between project cost and between specic process al-ternative costs. As a result, the predesign cost estimate is particularlysensitive to assumptions and qualications.

This is most important when designing for plant rehabilitation and op-erating facility expansion. It is also signicant when comparing processtypes and system components. And nally, it can be used when compar-ing costs for alternatives that include ultimate capacity versus currentow rates.

4.4 DEFINITION OF TERMS

Accuracy of the Estimate

The accuracy of a predesign cost estimate is taken from the guidelines of the American Association of Cost Engineers, International (AACEi) as apercentage range for estimating purposes. The accuracy ranges are iden-tied by the use of percentages / in reference to the expected actualconstruction cost of the work. These ranges differ with the type of esti-mate performed. (i.e., the Class 5 predesign cost estimate can be expectedto range from 50% to 30% of the actual cost of the project.) A graphicrepresentation in the appendix identies the accuracy range for eachclass and type of cost estimate.

Allowance for Additional Direct Costs

Due to the preliminary stage of the project, some conditions affecting thepricing and productivity could change. This percentage allowance is in-tended to cover work items not yet quantied but known to exist in projects of this type and size. This allowance is a variable percentage (%) of Total Direct Cost.

Denition of Terms 21


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Construction Costs

Construction costs are the sum of all individual items submitted in thesuccessful contractors winning bid through progress of the work, culmi-nating in the completed project, including change order costs.

Construction Cost Trending

A construction cost trending is the preparation and updating of theproject construction cost estimate over time. As the design process contin-ues, the project becomes more dened and as more detailed engineeringdata becomes available, trending provides a basis for the analysis of theeffects of these changes. These design and construction-related issues arethe documented, logged, and analyzed on a regular periodic basis duringthe design phase of the project. As each issue is resolved, it is included inthe trended cost estimate.

Contingencies

Contingencies are dened as specic provisions for unforeseeable cost el-

ements within the dened project scope. This is important where previous experience relating estimates and actual costs has established thatunforeseeable events are likely to occur. Allowances for contingencies arean integral part of the estimating process. Contingency analysis of costestimates is a useful aid to successful project performance. The periodicreview and analysis of these contingencies provide a myriad of opportuni-ties for project management to assess the likelihood of overrunning aspecied dollar amount, budgetary limitations, or time commitments.

However, many owners are hesitant to include unidentied contingenciesin their budgets. This may be because the owner believes that the engi-neer can and should identify all issues that impact the cost of construc-tion in advance of completing the design process. This is a fairassumption, but it invites cost creep during the design process andforces the owner to increase the construction budget of the project or loseprecious time in redesign.

Cost IndexesCost indexes are a measure of the average change in price levels overtime, for a xed market basket of goods and services. Commonly used in-dexes effecting construction costs are:



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The Consumer Price Index (CPI) : The Bureau of Labor Statistics of the U.S. Department of Labor produces monthly data on changes

in the prices paid by urban consumers for a representative basketof goods and services. It is applicable, in a general sense, to themonthly and annual change in the cost of goods and services inthe end user market. These would be price- level changes in aggre-gate including construction related goods and services for laborand incidental materials.

The Producer Price Index (PPI) : This is also prepared by the U.S.Bureau of Labor Statistics and measures the average change over

time in the selling prices received by domestic producers for theiroutput to the wholesale market. These are price-level changes inspecic manufactured products, including construction relatedgoods like cement, steel, and pipe.

The Engineering News-Record Construction Cost Index (ENR-CCI) :This is applicable in a general sense to the construction costs.Created in 1931 the ENR-CCI most nearly tracks the price-levelchanges in major civil engineering capital construction costs over

time. The Handy-Whitman Index of Water Utility Construction Costs :This has been maintained since 1949 and is applicable to waterand wastewater treatment plants. This index more closely approx-imates aggregate price-level changes in more complex treatmentplants and pumping stations.

The Marshall and Swift National Average Equipment Cost Index :This is specically for the tracking of complex equipment price-

level changes. It is useful in the indexing of pure equipment costsover time.

Escalation

All cost estimates are prepared using current dollars. In preparing a costestimate, an evaluation may be made to determine what effect inationmay have on the cost of the project extending some time into the future. An escalation factor is then applied to the total cost or bottom line of theestimate. A published cost index is the basis used for escalation shouldbe localized, reputable, and reective of the construction industry. Morespecically, the cost index used must be particular to the type of project being designed and constructed. This escalation may be used in

Denition of Terms 23


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conjunction with the cost-of-funds to prepare a present worth analysis of various project alternatives or construction phasing requirements.

4.5 ESTIMATING METHODOLOGY

The cost-estimating guidelines identied here comply with conventional,professional standards established by the AACEi. Project and process pa-rameters must be developed and a preliminary site layout established.Process parameters for this manual are in English units (i.e., gallons,feet, tons, etc.). The data used for this manual was compiled from actual

plant and process construction in the United States since 1970. The costdata has been normalized to a current construction cost index pub-lished monthly by the Engineering News Record , McGraw Hill, as theConstruction Cost Index (CCI).

Cost Capacity Curves

Cost capacity curves are charts that describe average costs of an item as afunction of capacity. The typical cost curve for water treatment processesis a smooth line drawn or tted through a scatter of real data points adjusted to a xed time by which the data is normalized. The informationon that chart would dene the construction cost for a process in dollars at various plant ow capacities at a xed point in time.

The cost and cost capacity curves relate to various process treatmentalternatives, pumping station capacities, reservoir storage capacities,and pipeline sizes and types, as well as other civil engineering projects.Other sources of cost and cost capacity curves cited below may also proveeffective and reliable when used correctly. Some of these published docu-ments are no longer in print, but copies may be available at various university or government locations.

Innovative and Alternative Technology Assessment Manual.February 1980 EPA/430/9-78-009 MCD-53.

Operation and Maintenance Costs for Municipal WastewaterFacilities. September 1981 EPA/430/9-81-004 FRD-22.

Construction Costs for Municipal Wastewater Treatment Plants:1973 1978. April 1980 EPA/430/9-80-003 FRD-11.

Treatability Manual, Volume VI, Cost Estimating. July 1980EPA/600/8-800-042d.



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Estimating Costs for Water Treatment as a Function of Size andTreatment Plant Efciency. August 1978 EPA/600/2-78-182.

Basis of Estimate

A brief description, in narrative form, of the work scope, assumptions,and qualications with details particular to the project should be pre-sented with the nished cost estimate.

Structure of the Estimate

The estimate is organized by both alternative treatment trains and spe-cic processes. A treatment train will include all processes specic to thatalternative. If there are alternative processes under consideration, a sep-arate treatment train must be created to include all necessary processesassociated with that alternative.

Once the alternative treatment trains are identied and their parame-ters calculated, their individual construction costs can be calculated fromthe process graphs or equations in this manual. Once the alternative pro-

cess treatment trains are identied and their construction costs esti-mated, additional site-specic parameters may be applied.These additional cost parameters could include: interconnecting con-

duit and yard piping, site demolition, earthwork, paving and grading,landscaping and irrigation, and electrical and instrumentation infra-structure. Separate curves and their parameters for these additionalcosts are included in this manual.

Estimate Global Mark-UpsThese mark-ups typically pertain to specic allowances for Escalation,Contingency, Construction Management, Inspection & Construction Ad-ministration, Design, Administration & Legal, Rights of Way Acquisi-tion, Environmental Mitigation, and Permitting. The construction costestimate may include any or all of these, depending upon the require-ments set by the client.

Comparison of Alternative Process Construction CostsWhen developing the alternatives, it is best to estimate costs for the en-tire treatment train that includes the selected alternatives. In this way, acomplete picture can be developed for the alternative analysis. Process

Estimating Methodology 25


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parameter values and their relative cost of construction may not differmuch. But, depending on how the selected processes are laid out and con-

nected on the site, the total cost of the train including the alternative pro-cess can be dramatically different. Land constraints, process hydraulicrequirements, and subsurface conditions can dramatically increase theoverall cost of the facility many times the difference in cost of two or morealternatives.

4.6 CAPITAL IMPROVEMENT COSTS

A capital improvement program can be made up of a number of individualprojects and span many years of development, design, and construction.The cost of a capital improvement program is usually developed withoutsignicant design input. Realistic budgets established early in the predes-ign phase can improve the likelihood of the programs success. Knowingthe reasonable cost of design, construction, and operation disruption onan annual basis can provide labor and cost savings and avoid delays thatwill invariably drive costs much higher than expected. A good realistic

plan, even one based on parametric ratios, can provide tools for a moresuccessful outcome or reduce the likelihood of an embarrassing failure.

Starting with a set of realistic construction cost estimates for multipletreatment trains that include unique costs for construction, operation,and maintenance, and additional nonprocess costs assists in evaluatingand selecting the project(s). By including the estimated time for the development, design, and construction the project costs can be spread overan annual calendar to assess the availability of capital, offsetting reve-

nue, and stafng required to make the program a success. And the esti-mate of cost and time begins with a reasonable and realistic processconstruction cost. As the estimating process is developed in Chapter 5, anallocation of costs for each parameter group will be made and a total capi-tal improvement cost model will be presented as an example of how it allts together.

Regulatory Impact

As was shown in Chapter 2, the historic changes in water treatment reg-ulations by both state and federal government agencies has, over the pre-ceding century, accelerated as a result of public concern, scientictesting, and technological improvements. With the increased burden of a



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growing population, limitations on waste disposal, and resistance tochange in the acceptance of water reuse, we can expect the acceleration

in regulatory response to continue. As a result, many of the treatmentprocesses that are the basis of water treatment design could become out-moded as more restrictive regulations on water quality are imposed. Thepresent cost of design and construction of advanced treatment facilitiesfor microltration and desalination are included in this manual.

Operations and Maintenance Costs

The costs of operating and maintaining an existing or new treatment fa-cility can vary from plant to plant even for the same owner. The operatingcosts are dependent to a great degree on the energy requirement andchemical dosage. These costs are directly related to the quality of the rawwater that must be brought up to a minimum good quality set by regu-latory agencies and plant hydraulics, which are dictated by the plant hy-draulic prole. If intermediate pumping is necessary, then the energycosts and maintenance costs for continuous pumping drive O&M costhigher. Labor costs are a factor but can be overshadowed by the cost of energy and chemical consumption. Larger chemical storage and feed fa-cilities are also regulated and becoming expensive and time-consumingto maintain. Simple parameters that are related to these processes areincluded in this manual. O&M cost curves are for each type of plant arediscussed and shown in Chapter 6.

Capital Improvement Costs 27


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Chapter 5

Water Treatment PredesignConstruction Costs

5.1 INTRODUCTION

In this chapter, we will identify and examine the parameters developedfor estimating construction costs. These parameters will then be ap-

plied to the nine types of water treatment plants specied in Chapter 2,at design ow rates of both 10 and 100 million gallons per day (MGD).The results will be made into tables for 43 different processes equationsbased on predesign parameters at the two design ow rates. We willalso present cost curves for advanced treatment plants including: fourtypes of seawater desalination plants, ultra-ltration and membraneltration.

In Chapter 2, we identied nine types of water treatment facilities,

each characterized by their unique design parameters and processes.These water treatment designs are listed again below by gure andname.

2.3.1a Two-Stage Filtration2.3.1b Direct Filtration2.3.1c Conventional Treatment2.4.1a Dissolved Air Flotation

2.4.1b Lime and Soda Ash Softening2.4.1c Iron Manganese Removal2.4.2a Micro Membrane Filtration2.4.2b Direct Filtration w/Pre-Ozonation2.4.2c Conventional Treatment w/Ozonation and GAC Filters

29



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Each of these plants types has unique processes and operating param-eters differentiating them from one another by purpose and ultimately by

construction costs based on those parameters. The two design ow ratesare one order of magnitude apart at 10 and 100 million gallons per day.Historical process costs have been gathered, sorted, tabulated, andgraphed to show the relationship between the process parameter andconstruction cost. Results consistently show it is not a one-to-one rela-tionship. For example, it doesnt cost twice as much to design and con-struct a circular clarier with a 100-foot diameter as to one with a 50-footdiameter. We have identied forty-three specic processes or facilities

that are currently used in water treatment plant design, prepared costcurves and compiled them into a total plant cost including nonprocesscosts common to the construction of these plants.

These cost and cost capacity curves have been developed for specictreatment process alternatives, pumping station capacities, clearwellstorage capacities, and process pipeline sizes and types, as well as othercomponents, including engineering design and construction supportcosts are made a part of this Cost Estimating Manual . Other sources

of cost and cost capacity curves cited below may also prove effective andreliable when used correctly. Some of these published documents areno longer in print but copies may be available at various university orother sources.

Estimating Costs for Water Treatment as a Function of Size andTreatment Plant Efciency , August 1978 EPA/600/2-78-182.

Innovative and Alternative Technology Assessment Manual , Feb-ruary 1980 EPA/430/9-78-009 MCD-53.

Construction Costs for Municipal Wastewater Treatment Plants:19731978, April 1980 EPA/430/9-80-003 FRD-11.

Treatability Manual, Volume VI, Cost Estimating , July 1980 EPA/ 600/8-800-042d.

Operation and Maintenance Costs for Municipal Wastewater Fa-cilities , September 1981 EPA/430/9-81-004 FRD-22.

5.2 TREATMENT PROCESS AND COST ESTIMATINGPARAMETERS

The processes we identify here have general parameters such as: squarefeet, gallons per day, lineal feet, and so on. These parameters are a way of

30 WATER TREATMENT PREDESIGN CONSTRUCTION COSTS


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comparing the relative size or function of the process against historic, up-dated construction costs. In this way, we generate a parametric curve so

that we can estimate the construction cost. Included in the appendix is ashort table of common conversions to the metric system used in the de-sign of water treatment plants. The curve functions developed here havebeen calculated using the standard single-variable trend line functionsavailable in an electronic worksheet. In most cases, the trend line func-tion that best t the data was a simple equation represented by (y aXn ).In some cases, the equation that best t data was of the form (y aX b).Both types of equations are supported by economic theory within a para-

metric range of one order of magnitude.Since the historic costs have occurred over many different years and

places within the United States, they were normalized to a commontime and place by using the published cost indices identied in Chapter 2.These curves were updated to an ENR CCI 8889 for Los Angeles, Cali-fornia (April 2007). Since the historic data has already been updated to acommon period and location, future updating of the cost curves are madeby multiplying the cost by the change in the applicable index, that is, for a

10% increase in the index the cost is multiplied by 110% to get the up-dated cost.

The following table of forty-three water treatment processes, facilitiesand additional nonprocess cost multipliers are the result of the analysis of historic actual costs. The resulting Total Project Cost is the sum of all con-struction costs, mark-ups, and engineering, legal, and construction ad-ministration costs in current dollars. This type of predesign cost estimateprovides a common basis for evaluating process alternatives against totalproject costs. By applying these costs curves to phased design and con-struction, a Present Worth analysis, using interest rates, and operationsand maintenance costs can assist the engineer and owner in choosing be-tween alternatives.

The table below lists an array of processes, cost equations, and range of application parameters. These cost equations and source data are com-piled into individual cost curves and detailed in the following section.

Before using the cost equations or curves, you must know the designcriteria for each process. For example; for the Clariers, Process Nos. 23& 24, Circular Clariers (No. 23) must use its accepted hydraulic loadingof 1.0 gpm/sf to 1.4 gpm/sf (avg. 1.2 gpm/sf). But Rectangular Clariers(No. 24) have a hydraulic loading rate of 0.5 gpm/sf to 1.0 gpm/sf (avg.0.75 gpm/sf ) without plate settlers. If you use 0.75 gpm/sf as the loading

Treatment Process and Cost Estimating Parameters 31


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rate circular clariers the cost becomes very expensive in relation to therectangular clariers.

5.3 COST CURVES

Each of these processes is also represented by a unique cost curve like theone for Figure 5.5.23 Circular Clariers. The curve is t to the data andrepresented by an equation and an r 2 or measure of colinearity. Since theoriginal data has been consolidated and an average value for each unit of parameter, the r2 simply tells us if the best t curve type is power(y aXn ), polynomial y aX2 bX c, or linear (y aX b) is themost appropriate.

Using either the equation function in Table 5.2.1 or scaling off theappropriate process curve, selecting the parameter of 17,000 SF for clari-er oor area drawing a perpendicular line from the curve where x 17,000 and a second line to the y-axis and estimate the value for the con-struction cost at approximately $1,4250,000. From the equation functiony 3470 : 6x0: 6173 where x 17,000 square feet of oor area the value forthe construction cost is $1,424,736. Although the equation delivers a moreprecise arithmetic answer, it is no more accurate than a rough line drawnon the graph. The likelihood of either number being correct is the same.

5.4 ESTIMATING PROCESS AND TOTAL FACILITIES COST

Each of the forty-three water treatment processes have a range of appli-cation, and we will briey discuss the limits, physical characteristics, andultimately the costs as they apply to the nine types of treatment plants

for both 10 MGD and 100 MGD.

5.5 INDIVIDUAL TREATMENT PROCESS COST CURVES

5.5.1 Chlorine Storage and Feed from 150-lb to 1-tonCylinders

Chlorine gas is purchased from the producer and delivered to the site tobe used as a disinfectant for the nish water delivered to customers of thewater treatment plant.

The smallest application is a 150-lb vertical tank with an eductor feedsystem. This application might be used as the only treatment for a smallsystem where the raw water is taken from a shallow aquifer and storedabove ground for relatively short periods of time.

32 WATER TREATMENT PREDESIGN CONSTRUCTION COSTS


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T a b l e 5 . 2 . 1 G e n e r a l C o s t E q u a t i o n s f o r W a t e r T r e a t m e n t P r o c e s s e s w i t h P a r a m e t e r s , M i n i m u m a n d M a x i m u m L i m i t s

N o .

P r o c e s s

C o s t E q u a t i o n

M i n

M a x

1 a

C h l o r i n e s t o r a g e a n d f e e d

1 5 0 # c y l i n d e r s t o r a g e

$

1 ; 1 8 1 : 9 X ^ 0 : 6 7 1 1 X

C h l o r i n e f e e d c a p : - L

b = d

1 0

2 0 0

1 b

C h l o r i n e s t o r a g e a n d

f e e d 1 - t o n c y l i n d e r s t o r a g e

$

5 ; 2 0 7 : 4 1 X ^ 0 : 6 6 2 1 X


b = d

2 0 0

1 0 , 0

0 0

2

O n - s

i t e s t o r a g e t a n k w i t h r a i l d e l i v e r y

$

6 3 ;

6 4 0 X ^ 0 : 2 6 0 0

X


b = d

1 , 9 8 0

1 0 , 0

0 0

3

D i r e c t f e e d f r o m r a i l c a r

$

6 9 ;

7 7 8 X ^ 0 : 2 2 4 5 X


b = d

1 , 9 8 0

1 0 , 0

0 0

4

O z o n e G e n e r a t i o n

$

3 1 ;

0 1 5 X ^ 0 : 6 4 7 5 X

O z o n e G e n e r

: C a p

: - L

b = d

1 0

3 , 5 0 0

5

O z o n e C o n t a c t C h a m b e r

$

8 9 :

2 1 7 X ^ 0 : 6 4 4 2 X

C h a m b e r V o l u m e - G A L

1 , 0 6 0

4 2 3 , 0 0 0

6

L i q u i d A l u m F e e d

$

6 9 9 : 7 8 X 8 8 5 2 6 X

L i q u i d F e e d c a p : - G a l

= h

2

1 , 0 0 0

7

D r y A l u m F e e d

$

cost estimating manual for water & wastewater treatment facilities

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