ULQNLQJ :DWHU...the IDSE, as part of the Stage 2 D/DBPR. The USEPA used the study findings to finalize the Stage 2 D/DBPR. Study results have also been published in the AWWA manual:

QUALIFICATIONS

water quality

Drinking

Water

distribution system

qualificationsDrinking

Water

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219

p r e f a c e / c o n t e n t s

Carollo Engineers is an environmental consulting firm with more than 1,050 employees in 44 offices throughout the United States. All of our work is performed in the areas of water and wastewater, resulting in a level of understanding of key project issues that few can match. Carollo strives to maintain the tradition of using sound and proven engineering principles while moving progressively forward to keep abreast of changing times and new technologies.

This is a specialty Statement of Qualifications (SOQ) for Carollo Engineers detailing some of our experience and expertise in the field of water treatment specific to this topic.

CONTENTS

Issues and Differentiators

Key Achievements

Testing and Optimization Capabilities

Publications

Company Profile

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DIStRIBUtIOn SYSteM WAteR QUALItY CHALLenGeSThe significance of the distribution system as a potential source of contamination of potable water can be illustrated by the mag-nitude of piping currently in service. An estimated 880,000 miles (1.4 million km) of distribution piping are currently used in the U.S. to convey potable water to roughly 223 million people (USEPA Distribution System White Paper - New or Repaired Water Mains).

Regulatory officials are now recognizing the importance of address-ing distribution system water quality. As such, future regulations may place a stronger emphasis on the distribution system than past regulations. In response to the impending regulations that pertain to distribution system water quality, many utilities have changed their treatment strategy including their use of primary, intermediate and final disinfectants. Because some of these regulations are conflicting, they create a significant burden on water suppliers. As an example, a change in disinfection practice may increase a utility’s ability to com-ply with one regulation, while introducing secondary impacts that may compromise its ability to comply with other regulations.

Summary of Distribution System Water Quality Issues

Biological Issues Physical Issues Chemical Issues Aesthetic Issues

• Cross-contamination• Biomass growth • Nitrification• Backflow• Biofilms

• Aging water and dead-ends• Pipe corrosion • Aging infrastructure• Incompatibility between

disinfectant and infrastructure components

• Inadequate mixing in tanks and reservoirs

• Blending of different water types in the system

• Hydraulic conditions• Presence of sediments and

debris

• Exposure to excess chlorine• Loss of disinfectant residual• Formation of undesirable

disinfection by-products• pH instability• Blending of two types of

disinfectants• Corrosion inhibitors

• Customer Dissatisfaction• Taste and odor• Switch of disinfectant• Algae growth in treated open

reservoirs• Iron, manganese, and other

particulate deposits• Hard water, soft water• Color

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Requirements for distribution system disinfectant residuals and microbial contaminants are regulated by the Surface Water Treatment Rule (SWTR), which was promulgated in June 1989. Among others, the SWTR outlines distribution system disinfection requirements to inactivate microbiological pathogens for systems using surface water sources. Under the rule, a measurable disinfec-tant residual must be maintained in at least 95 percent of the samples from the distribution system each month, for any two consecutive months. Samples with HPC levels less than 500 CFU/mL are consid-ered to have a detectable disinfectant residual.

The distribution system microbial integrity is monitored via a micro-bial indicator, the coliform group. The Total Coliform Rule (TCR) promulgated in 1989 is associated with the SWTR and established a maximum contaminant level goal (MCLG) of zero coliform. The rule allows no more than 5 percent positive samples per month for systems that collect 40 or more samples per month. In systems that collect fewer than 40 samples, no more than one sample may be posi-tive. The TCR requires that a minimum disinfectant residual of 0.2 mg/L for free chlorine or 0.5 mg/L for chloramines be present as the water enters the distribution system.

In terms of disinfection byproduct control, the Stage 1 Disinfectants/ Disinfection By-Products Rule (D/DBPR) was promulgated in December of 1998. maximum contaminant levels (MCLs) of THM4 and HAA5 were established for point of entry, average, and maxi-mum residence time distribution system sites. The D/DBPR also includes MCLs for other DBPs such as chlorite and bromate, maxi-mum disinfectant residual levels for chlorine, chloramines, and chlorine dioxide, treatment strategies for high total organic carbon (TOC)/low alkalinity waters to address precursors of DBPs, and best available technologies (BATs) to achieve the MCLs.

The Stage 2 D/DBPR published on December 15, 2005, builds on the Stage 1 D/DBPR. It addresses the health risks of DBPs in distribution systems that add a primary or residual disinfectant other than ultravi-olet (UV) light or deliver water that has been treated with a primary or residual disinfectant other than UV. The Stage 2 D/DBPR modi-fies the method of calculating compliance DBP results by establishing locational running annual averages (LRAAs) instead of RAAs. Some of the key provisions of the Stage 2 D/DBPR include:

An initial distribution system evaluation (IDSE) to identify !

compliance monitoring locations that represent high THM4 and HAA5 concentrations throughout the distribution system.

An LRAA calculated for each monitoring location in the distribu- !

tion system for THM4 and HAA5.

To ensure the delivery of high-quality

potable water to the customer's tap,

regulators are placing a stronger

emphasis on water quality in the

distribution system.

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Consecutive systems. !

Operational evaluation levels to document significant excursions !

of THM4 and HAA5.

The challenge thus lies in preserving the biological integrity of the distribution system by maintaining a minimum disinfectant residual, while maintaining halogenated DBP levels below the MCLs. To ensure the delivery of high quality potable water to customers’ tap, water utilities need to optimize their distribution system operation and maintenance practices in regards to disinfectant residuals, micro-organisms, DBPs, metal release and uptake, color, taste and odor, etc.

DIStRIBUtIOn SYSteM ReSeARCH eFFORtS AnD PRACtICAL SOLUtIOnSHistorically, water suppliers were focusing on producing treated water that complies with all established federal and state regulations at the water treatment plant effluent. Little thought was given to the fate of water quality as water flows through miles and miles of distribution system pipes and tanks. More recently, a stronger focus was placed on the water quality in the distribution system and the infrastructure itself. This change in focus was partially driven by the availability of new information, aging infrastructure, and customer inquiries, namely heath and safety concerns.

At Carollo, we are active on the regulatory, research, and practical levels of distribution system water quality issues. This is demonstrated by our staff’s commitment and active involvement in the following key activities:

Distribution system projects at all levels, including research and !

industry.

Development of guidance manuals, book chapters, journal publi- !

cations, and other outreach documents.

Presentations at local, regional, national, and international con- !

ferences, workshops and seminars.

Participation in regulatory activities. !

Select solutions to distribution system water quality issues are sum-marized in the table on the following page.

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Research experience

Understanding the factors affecting water quality in the distribution system is critical for the development of optimal treatment solutions and distribution system management techniques. Because of the variety and complexity of factors affecting distribution systems, con-ducting specialized studies at the bench or pilot scale can help isolate one factor at a time and better relate causes and effects. Carollo has completed a number of research projects that address these issues, including:

A critical full-scale study for the Water Research Foundation !

investigating the formation and decay of decay of DBPs in distri-bution systems. Participating utilities included free chlorinated

Distribution System Water Quality Issue

Practical SolutionCarollo Staff’s

Experience

Conversion from chlorine to chloramines

• Develop nitrification action plan.• Prepare monitoring plan.• Review water quality data closely before, during, and after

the conversion.• Size and design chemical feed system.• Review distribution system and reservoirs operation and

maintenance practices.• Provide revised operations plans based on distribution system

computer modeling and water age analysis.• Review distribution system materials with regards to their

ability to resist chloramines.

3

Blending challenges of free chlorinated with chloraminated water

• Develop blending plan.• Prepare nitrification action plan and response guidelines.• Computer model water age and water quality.

3

High concentrations of disinfection by-products

• Minimize dead-ends and other remote locations.• Increase turn-over of reservoirs.• Switch disinfectant.• Improve treatment processes to minimize the formation of

DBPs.

3

Nitrification

• Reduce water age with a revised operations plan based on calibrated distribution system computer modeling.

• Increase turn-over of reservoirs.• Optimize reservoir mixing.• Establish uni-directional flushing programs.• Establish chlorine or chloramine boosting stations.• Review treatment and disinfection strategy to optimize water

quality in the distribution system.

3

Cross-contamination• Design modifications to air valves and blow-off structures to

prevent cross-connection in distribution systems. 3

Corrosion

• Develop corrosion management plans including: - Adjustment of pH and hardness. - Addition of corrosion inhibitors.• Design corrosion protection systems including sacrificial

anodes and cathodic protection.

3

Hydraulic conditions • Develop and calibrate hydraulic models • Master plan to prevent under or oversizing of distribution

system infrastructures.3

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systems, chloraminated systems, and a chloraminated system that switch to free chlorine on a temporary basis. The project resulted in a decision tool to assist utilities in selecting compliance sites for the IDSE, as part of the Stage 2 D/DBPR. The USEPA used the study findings to finalize the Stage 2 D/DBPR. Study results have also been published in the AWWA manual: Water Quality in the Distribution System (2005).

A Water Research Foundation bench-, pilot-, and full-scale study !

investigating the impact of water quality conditions in distribution systems on microorganism inactivation. Ultimately, the project provided information about the minimum disinfectant residual that can adequately maintain microbial quality of treated drinking water under typical distribution system operation. Study results will be used by regulators to revise the Total Coliform Rule (TCR) and determine the needs and specifics of a possible Distribution System Rule.

A recent Water Research Foundation project that developed a !

comprehensive manual to guide identification of particulate mat-ter in distribution systems Aesthetic issues, such as particulate matter in water at the consumer’s tap and taste and odor, are perhaps the most important issues facing water utilities in terms of dealing with consumer confidence in the quality of their drinking water.

Carollo also maintains extensive and readily available bench- and pilot-scale equipment for use in treatment simulations, including secondary disinfection schemes. In addition, Carollo owns equipment to assess water quality changes in simulated distribution systems.

The benefits of in-house equipment for testing include flexible and customized testing, and rapid turnaround of water quality analyses and data reduction. Ultimately, this contributes to the development of cost-effective solutions for our clients.

Practical Utility experience

Carollo’s experience does not stop at the research level. We use lessons learned from our research projects to identify and develop practical solutions for the many challenges affecting full-scale distribution systems. Carollo has assisted several utilities during the conver-sion of their distribution systems from free chlorine to chloramine disinfection. Practical solutions include the

development of nitrification action plans, development of monitoring plans, and the formulation of preventive action and active response plans. Other services include the optimization of utilities’ tank and reservoir management plans, which involve flushing, mixing, and turn-over. Key projects include:

Carollo was a key

participant in

updating a Water Research

Foundation guidance

manual for chloramine

treatment considered by

operators everywhere as

the standard for chloramine

users.

The findings from Carollo's Water Research

Foundation study investigating the formation and

decay of DBPs in distribution systems will be used

by the USEPA to finalize the Stage 2 D/DBPR.

c, '. 1:*0_ " ..... - •

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Synthesizing relevant operational and practical information on the !

use of chloramines in drinking water treatment and developing revised operational chloramination guidelines. These guidelines will be published in an AWWA manual and used by treatment plant operators.

An important study of customer perception of tap water chlori- !

nous flavors. The study found that consumers generally have a negative opinion of chlorinous tastes and odors in their drinking water and that the perception of this flavor leads to lower satisfac-tion with tap water, including health and safety concerns. The study concluded that consumer satisfaction can be increased by: 1) improving customer knowledge regarding tap water quality and the safety of chlorinated tap water, 2) reducing chlorinous flavors in finished water, and 3) educating consumers about drinking water treatment and distribution. Recommendations included modifying Consumer Confidence Reports/ Annual Water Quality Reports by providing more user-friendly information, and focusing on safety and health issues.

In addition to evaluating key issues of concern and providing opera-tional recommendations to utilities, Carollo has also designed various capital improvements that help our clients maintain excellent distri-bution system water quality. Examples include:

Distribution system modifications that facilitate moving older !

water from low water demand areas to high water-demand areas.

Pump station modifications to facilitate filling reservoirs more !

quickly for controlling water age.

Remote chemical monitoring and additional facilities to address !

low disinfectant residual, and correct chlorine to ammonia ratios at remote portions of the distribution system.

Various types of reservoir mixing strategies including internal and !

external check valve arrangements, separating inlets and outlets, and other types of mechanical mixers.

Preliminary design for modifications to air valves and blowoff !

structures to prevent cross-connection and contamination in distribution systems.

Assisting a research and development firm in the development !

and validation of an innovative mixing technology to improve mixing efficiency, reliability, and reduce power consumption in drinking water reservoirs.

Results from a recent Carollo study on

customer attitudes towards drinking tap

water revealed that, although 72 percent

claimed to be satisfied with their drinking

water quality, only 52 percent drank it,

and only 21 percent drank it regularly.

60%

0%

30%

20%

10%

DrinkTap Water

Drink TapWater Regularly

40%

50%

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Water Quality Modeling for Optimum Delivery to System Customers

One key piece of a properly managed distribu-tion system is the availability of a well-calibrated hydraulic model. The hydraulic model is the first component in the preparation of a water quality model, which can be used to simulate water quality changes along the pipes and nodes. Carollo has expertise in developing, calibrating and imple-menting models, and has assisted several clients in modeling their distribution system, which can then be used to serve master planning needs.

Carollo uses hydraulic and water quality models to help its clients better understand how water flows throughout their distribution systems, and to identify any potential areas of concern. For example, we use simulated tracer studies to assess how groundwater and sur-face water sources blend in the distribution system, and determine the potential for water quality issues such as taste and odor and low chlorine residual that may result at the blending areas. We use similar techniques to assess daily and seasonal distribution system flow patterns to identify low flow or “dead zones” in distribution systems where water can age, and potentially lead to localized water qual-ity problems such as nitrification. Using our model analyses, we can better identify potential upgrades to improve water flow in all areas of the system and determine optimal water quality monitoring sites, enabling purveyors to deliver the highest quality of water possible to their customers.

Carollo has a long successful history in water distribution system master planning. We have completed over 100 water system master plans in the last 15 years.

Water quality analysis, such as

source tracing, is an important tool to

understanding system performance.

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The project profiles on the following pages present highlights of Carollo’s key achievements in distribution system water quality. These examples illustrate our ability to:

Implement innovative technologies to improve process design and !

performance.

Integrate engineering and research to achieve practical solutions !

tailored to specific client needs.

Involve project participants early in the process to “demystify ! ” advanced technology and fully understand each other’s needs.

Offer advanced solutions that are practical, affordable, and reli- !

able.

Upon request, we would be happy to provide client references that can attest to the quality and responsiveness of Carollo’s services.

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City of AvondAle, ArizonA

Distribution System Water Quality Monitoring Study

Conceptual design of remote distribution system water quality monitoring

station.

Real-time water quality monitoring technology

review.

Conversion of hydraulic network model to

extended Period Simulation (ePS) model.

HIG

HL

IGH

TS

Carollo Engineers performed a distribution system water quality moni-toring study and conceptual design for the City of Avondale. The City’s main objectives for this project were to develop strategies to:

Collect real-time water quality data from the distribution system to !

improve operations.

Identify areas of the distribution system with water quality challenges. !

Provide an early warning of potential contamination events (inten- !

tional or unintentional).

In order to achieve these objectives, the project consisted of the follow-ing main tasks:

Summarize distribution system water quality considerations and regu- !

latory requirements.

Identify critical water quality parameters for monitoring. !

Research and evaluate technologies for monitoring distribution sys- !

tem water quality in real-time, including cost impacts.

Convert the City’s network hydraulic model to an EPS model. !

Establish design criteria and develop a conceptual design for various !

configurations of remote water quality monitoring stations capable of real-time measurement of critical water quality parameters.

Define strategies for identifying and prioritizing monitoring station !

locations.

The team researched and evaluated numerous real-time monitoring systems on the market. The evaluation focused on technologies that had been tested by the Environmental Technology Verification (ETV) pro-cess by the USEPA. Technologies were evaluated based on the number and type of water quality parameters that could be measured; accuracy of the analyzers; SCADA communication capabilities; and cost, among others.

Multiple conceptual designs were developed to address potential moni-toring station configurations, including incorporating the station into an existing City-owned facility; an underground vault within the right-of-way; and a stand-alone above-grade facility. Preliminary cost estimates were developed for each configuration and a ranking system was devel-oped to identify the configuration that best met the City’s goals.

A placement optimization tool, such as TEVA-SPOT, was recommended to optimize the location and number of monitoring stations throughout the City’s distribution system.

Carollo completed a technology review of

real-time water quality monitoring systems

for implementation in the City’s distribution

system.

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Distribution System Water Quality Monitoring Station Design and Construction Management

Performed detailed design and construction documents for remote

distribution system water quality monitoring station.

Remote facility communicates real-time water quality data and

alarms to the City’s SCADA system.

Provided construction management and

inspection services.

HIG

HL

IGH

TS

As part of a waterline extension project, Carollo Engineers prepared construction drawings and specifications for the first distribution sys-tem water quality monitoring station for the City of Avondale. The monitoring station is to help the City achieve the following goals:

Collect real-time water quality data from the distribution system !

to improve operations.

Identify areas of the distribution system with water quality chal- !

lenges.

Provide an early warning of potential contamination events !

(intentional or unintentional).

The station is designed to be configured in a remote underground vault within the right-of-way (determined during preliminary design). The buried vault provides an added measure of security against theft and vandalism, locates the monitoring equipment near the water main, and avoids the extra cost of purchasing land and developing a new site.

The design includes a real-time water quality monitoring system with provisions to communicate the data stream, as well as any alarms, to the City’s SCADA system. The monitoring system is capable of measuring multiple critical water quality parameters, analyzing the data to determine whether there is an anomaly, and automatically takes mul-tiple samples for confirmation testing if contamination is detected. Non-hazardous sample waste is drained to a sump and then pumped to the sewer.

In addition to design services, the team provided bid sup-port during the contractor selection process and construc-tion management services.

Carollo designed and provided construction

management services for the City’s first remote

distribution system water quality monitoring station

designed to support operations and provide an early

warning of contamination.

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Distribution System Water Quality Sensor Placement Optimization Study

Collaborated with ePA nHSRC to beta-test

newly-developed sensor placement optimization

tool (teVA-SPOt).

Identified optimum number and location

of real-time sensors to protect the public against

health impacts from a contamination event.

HIG

HL

IGH

TS

In collaboration with the US Environmental Protection Agency (EPA) National Homeland Security Research Center (NHSRC), Carollo Engineers performed a Distribution System Water Quality Sensor Placement Optimization Study for the City of Avondale. The City is in the process of implementing a network of distribution sys-tem water quality monitoring stations (sensors) aimed at optimizing operations for water quality and detecting contamination events. The objectives of the study are to:

Optimize sensor placement in the distribution system to minimize !

the public impact of a contamination event.

Optimize the number of sensors to cost-effectively provide human !

health protection.

This project is a collaborative effort between Carollo, EPA NHSRC and the City of Avondale to apply a newly developed water security tool to a real-world distribution system. The tool is called Threat Ensemble Vulnerability Assessment-Sensor Placement Optimization Tool (TEVA-SPOT), Graphical User Interface (GUI) version. The EPA tool uses a hydraulic network model and optimization algo-rithms to simulate a wide range of contamination events, measure

the resulting public health impact and recommend the number and location of sensors that maximizes human health protection.

Carollo was trained on TEVA-SPOT GUI by EPA staff and worked with the City to develop user-specified inputs for the model, including the design basis threat, performance measures, potential sensor locations and utility response measures, among others. Model results were periodically verified and reviewed by EPA staff to help ensure quality. Carollo provided feedback to EPA on potential improvements to the model.

Project deliverables included master plan maps of recom-mended sensor locations; graphs showing the relation-ship between the number of sensors and public health impacts; and potential costs for optimized sensors, among others.

Carollo collaborated with EPA to beta-test newly-

developed sensor placement optimization tool (TEVA-

SPOT) to optimize number and location of real-time

sensors to detect distribution system contamination.

Carollo was first engineering firm to collaborate with EPA

on the application of TEVA-SPOT.

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WAter reseArCh foundAtion

Formation and Decay of Disinfection By-Products in Distribution Systems

evaluation of the behavior of trihalomethanes

and haloacetic acids in distribution systems.

Impact assessment of dynamic water quality

conditions in distribution systems on the

inactivation of suspended microorganisms.

Development of guidance tools critically needed by the water industry

to manage disinfectant residuals.

HIG

HL

IGH

TS

Carollo recently conducted a Water Research Foundation project that dealt with key distribution system issues. The goal of the proj-ect, entitled “Formation and Decay of Disinfection By-products in Distribution Systems,” was to evaluate critical factors that effect THM and HAA behavior in distribution systems, to determine the fate and behavior of other critical DBPs (such as NDMA, bromate, haloacetonitriles), and to identify by-products of DBP degradation. This project provided important information for utilities to address the Stage 2 Disinfectants/Disinfection By-Products Rule.

Key features of this extensive one-year study investigating the formation and decay of DBPs in five full-scale distribution systems included:

Evaluation of distribution systems that featured free chlorine !

final disinfection, chloramine final disinfection, and systems that periodically converted from chloramines to free chlorine disinfection.

Inclusion of booster stations and reservoirs. !

Use of calibrated hydraulic models to select !

distribution system sites for the study.

Selection of sites that showed signs of biolog- !

ical degradation of HAAs.

Selection of sampling locations that repre- !

sented various water ages (i.e., ranging from close to the treatment plant to dead-ends).

Selection of sampling locations that con- !

sidered pipe material and diameter, as well as pressure zones and possible presence of automatic flushers.

By applying the results of the study, Carollo developed practical deci-sion and operational tools for determining distribution system sites to comply with the Stage 2 D/DBPR. These tools would be more user-friendly than the guidance manuals available thus far to help utilities select their monitoring sites for compliance.

This Water Research

Foundation study provided vital

information on the minimum

disinfectant residual that can

adequately maintain microbial

drinking water quality under

typical distribution system

operation.

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Qualitative Procedures for Identifying Particulate Matter in Distribution Waters and at the Customer’s tap

A step-by-step decision tree framework that will

facilitate the identification of the particulate matter

found in distribution systems and tap waters.

A detailed set of procedures for specific

particulate matter identification methods, developed and refined

during this project.

A CD-ROM photo library of types of particulate matter under various conditions representative of drinking

water treatment and distribution.

HIG

HL

IGH

TS

The microscope is used (above) to view and

identify a carbon fine (upper left) and an oil

droplet (lower left).

A common and important customer complaint concerning drink-ing water is the presence of unknown particulate matter. Often, the nature and source of the particulate matter is not investigated, because utilities do not know the origin of the problem. There are a number of possible sources for the various types of particulate mat-ter; some may originate in the source water, whereas others may come from utility-operated facilities or household plumbing. A key to dealing with this issue is the formulation of a step-by-step set of instructions to identify the particulate matter and demonstrate the findings to the consumer. This identification will also help determine the significance and origin of the matter.

The overall objective of this project was to develop a user-friendly manual of step-by-step procedures for identifying types of particles in distribution system and tap waters. Specific objectives included:

Developing a decision tree framework to allow !

stepwise progress toward a positive identification and to determine the significance of the particu-late matter.

Demonstrating and refining the application of the !

decision tree framework and associated methods in on-site workshops by receiving immediate feed-back from the participating utilities.

Identifying, improving, and enhancing existing wet !

chemistry and advanced analytical techniques for the identification of particulate matter.

Producing a comprehensive photo library (CD- !

ROM format) of example types of particulate mat-ter found in North American distribution systems and tap waters.

Participating utilities in this project included the Columbia Water Treatment Plant (Missouri), Grand Strand Water and Sewer Authority (South Carolina), Crescenta Valley Water District (California), City of Cedar Rapids Water Department (Iowa), Duck River Utility Commission (Tennessee), and the City of Washington (Missouri).

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City of PAsAdenA, CAliforniA

Conversion of Chlorination Facilities to Chloramination Facilities at Sunset and Windsor Reservoirs

evaluation of Pasadena's chloramination approach.

Review of existing reservoir configurations and operations, water

quality goals and regulations, and O&M

requirements.

Development of alternatives for resolving

operational problems.

Predesign of recommended changes

HIG

HL

IGH

TS

The City of Pasadena purchases chloraminated water from the Metropolitan Water District (MWD) of Southern California to supplement its own groundwater supplies which are disinfected using chlorine. Blending of the two sources creates problems, including a loss of disinfectant residual, nitrification, and taste and odor episodes.

In addition, Pasadena is concerned about its ability to meet the Stage 2 D/DBPR while using chlorine. Faced with these challenges, Pasadena retained Carollo to evaluate the situation, develop solu-tions, and prepare a predesign of the selected alternative.

Carollo evaluated the Pasadena’s chloramination approach by review-ing existing reservoir configurations and operations, water quality goals and regulations, and O&M requirements. Carollo developed

alternatives for resolving operational problems resulting from blending chlorinated groundwater and chloraminated water supplied by MWD and prepared a complete predesign of the recom-mended changes. Carollo also held a series of workshops throughout the project to promote consensus decisions between Pasadena and Carollo.

Carollo worked with the City of Pasadena

to develop alternatives for minimizing

chlorinated/chloraminated blending issues

in the distribution system.

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sAntA ClAritA WAter division And neWhAll County WAter distriCt, sAntA ClAritA, CAliforniA

Consulting Services

Chloramine conversion.

nitrification action plan.

Municipal water quality services.

HIG

HL

IGH

TS The Castaic Lake Water Agency, which sells water to Santa Clarita

Water Division and Newhall County Water Districts, recently switched their final disinfection from free chlorine to chloramines. This triggered Santa Clarita Water Division and Newhall County Water District, which were both on free chlorine disinfection in their system, to come up with an action plan to minimize issues of blend-ing free chlorinated water with chloraminated water. As part of this effort, Carollo assisted Santa Clarita Water Division and Newhall

County Water District with the following:

Development of Nitrification Action Plans !

(NAP) and follow-up with California Department of Health Services (CDHS). The NAP included a monitoring and prevention protocol, and response actions to nitrification.

Distribution system water quality data analy- !

sis before, during, and after the switch to chloramines.

Recommendations and response plans to poten- !

tial issues of concern.

Services provided to Newhall County Water District included the following:

Finalizing the Annual Water Quality Report. !

Developing source water sampling schedule. !

Compiling general distribution system water !

quality data.

Carollo provided consulting services for chloramine

conversion and developed a Nitrification Action Plan

for the Santa Clarita Water Division and Newhall

County Water District.

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16

Mid-PeninsulA WAter distriCt, BelMont, CAliforniA

Chloramine Conversion Study

Conversion from chlorine to chloramines.

Water distribution system modeling.

Capital and operational improvements.H

IGH

LIG

HT

S Carollo completed a study for the Mid-Peninsula Water District (MPWD) to evaluate converting from chlorine disinfection to chlo-ramine disinfection. MPWD receives water from the San Francisco Public Utilities Commission (SFPUC), which converted to chlora-mine disinfection in the year 2003. Though chloramines are more stable than chlorine, the conversion posed significant water quality issues, including nitrification and bacterial growth in the water distri-bution system if the proper operational procedures were not planned and implemented.

Carollo prepared a computer model of MPWD’s water distribution system using H2ONET® that not only helped to identify potential problem areas, but also helped evaluate remedial measures. Carollo evaluated both capital improvements and operational changes to identify those that would most cost effectively help the MPWD maintain high water quality throughout its distribution system follow-ing the SFPUC’s conversion to chloramine disinfection. Carollo pre-sented the results of the study and the recommended improvements and operational changes in a report that included estimated costs and the recommended schedule for completion.

Carollo evaluated the Mid-Peninsula Water District’s pump

station design and operation to verify proper system function

and maintain water quality.

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17

Zone 3

Zone 2Zone 1

Zone 4

MiramonteReservoir

SCVWDConnection

MiramontePS

Well#9

250 hrs

30 hrs25 hrs

40 hrs

60 hrs

75 hrs

75 hrs

100 hrs

100 hrs

150 hrs

Well#20

Well#19

Well#21

Well#17

Well#10

Whisman Reservoir

SFPUC BAY DIVISIONPipelines 3 and 4

Mv1200f6-6079.cdr

LEGENDReservoir

Distribution Pipe

Zone Boundary

Pump Station (PS)Pressure RegulatingStation (PRS)

SFPUC Turnout

SCVWD Turnout

SFPUC Bay DivisionPipelines 3 & 4

WellWater Ages

Whisman SFPUC#14 Turnout

Escuela SFPUC #5 Turnoutto Zone 1

Escuela SFPUC #7 Turnoutto Zone 2

125 hrs

WhismanPS

City of MountAin vieW, CAliforniA

Chloramine Conversion Study

Water distribution system planning.

Operation modeling.

Water quality modeling.

HIG

HL

IGH

TS Carollo completed a study for the City of Mountain View to evalu-

ate converting its distribution system from chlorine disinfection to chloramine disinfection. Mountain View receives its water from the City of San Francisco Public Utilities Commission, which converted from chlorine to chloramines in the year 2003. Though chloramines are more stable than chlorine, the conversion posed significant water quality issues, including nitrification and bacterial growth in the water distribution system if the proper operational procedures are not planned and implemented.

Carollo prepared a computer model of Mountain View’s water distri-bution system to help identify potential problem areas and evaluate remedial measures. Carollo evaluated both capital improvements such as pipe looping and reservoir mixing systems, and operational changes such as pump controls and operational schemes. Based on the results of the study, Carollo prepared a report that provided recommended improvements, costs, and an implementation schedule to help Mountain View maintain high water quality throughout its distribution system in the most economical fashion.

Carollo’s water distribution

system computer model

identified potential problem

areas and remedial measures

for chloramine conversion.

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18

Advanced Water treatment of estuarine Water Supplies

Investigation of advanced treatment technologies

and disinfectant combinations for estuarine

supplies.

Determination of additive and synergistic effects

of multiple disinfectants/oxidants.

treatment technologies that include granular

activated carbon, MIeX® resin, and membranes.

HIG

HL

IGH

TS

Estuarine waters (fresh waters under tidal influence) are an impor-tant source of drinking water for millions of people These waters pose a number of treatment challenges, including salt and bromide intrusions from seawater, as well as the presence of DBP precursors and anthropogenic chemicals from upstream discharges. Considering these challenges, successful treatment scenarios need to include a multiple-barrier approach.

The Water Research Foundation and the USEPA provided funding to the Contra Costa Water District, who then retained Carollo to study advanced water treatment of estuarine waters. The goal of this project is to fill knowledge gaps regarding treatment of estuarine sup-plies using existing and advanced technologies, as well as disinfectant combinations. The aim is to meet current and future regulations as well as drinking water utilities’ water quality treatment goals. Project objectives include:

Investigating the additive and synergistic effects of multiple !

disinfectants/oxidants, including chlorine, chloramines, chlorine dioxide, ozone, and UV disinfection on disinfection efficay and DBP formation.

Investigating a selection of advanced technologies, namely coagu- !

lation, powdered activated carbon (PAC), granular activated car-bon (GAC), MIEX® resin, and membranes, to remove dissolved organica carbon, bromide, and taste and odor compounds prior to disinfection in estuarine waters.

Investigating the impact of multiple disinfectants and the pro- !

posed advanced technologies on distribution system water quality, including disinfection by-product formation, nitrification, and microbial regrowth.

Determining the threshold levels of source water quality and !

associated disinfection requirements; identifying whether optimi-zation, retrofit, or installation of advanced technologies may be required, and recommending the treatment levels necessary to achieve regulatory horizon targets.

Determining practical operational conditions and limitations of !

the technologies tested, and proposing alternatives and solutions to meet regulatory requirements.

Providing a comparative cost analysis for the proposed solutions, !

including operating requirements.

Carollo is investigating advanced

treatment technologies and disinfectant

combinations for estuarine supplies,

including, two types of UV lamps.

ContrA CostA WAter distriCt, ConCord, CAliforniA/WAter reseArCh foundAtion/usePA

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19

dwq805f1.cdr

Controller

Feed RateControl ValvePressure

Reducing Valve

Meter

Evaporator(if necessary)Anhydrous Ammonia

Storage

Flow Monitor orChlorine Residual

Analyzer

Water Softner(if necessary)

Process Stream

SolutionDiffuser

AmmoniatorInjector

Pump

Solu

tion

Line


Optimizing Chloramine treatment

Review of chloramine treatment.

Best management practices manual.

Community relations to gain input and support on

the use of choramines.HIG

HL

IGH

TS

This project involved a collaboration between Carollo, American Water and Economic and Engineering Service (EES) to update the original Optimizing Chloramine Treatment Manual (Water Research Foundation, 1993). Its goal was to synthesize all relevant research, operational and practical information on the use of chloramines in drinking water treatment, and develop new utility case studies into an updated best management practices manual that will have an operations and implementation focus. The project developed “practi-cal chloramination guidelines for use in the utility operation tool-box,” focusing on four key objectives:

Decision approach: helping the utility decide whether to use !

chloramines.

Design guidelines for safe and reliable treatment facilities. !

Start-up and operations of chloramine treatment facilities. !

Community relations: approaches to gain input and support. !

To meet these goals and objectives, the team devel-oped a five-step approach:

Assembling the latest information. !

Developing and conducting a chloramine survey. !

Identifying and conducting case studies. !

Preparing new chloramine guidelines. !

Empowering the user. !

The team developed and conducted a survey of all relevant operational and practical information,

problems encountered, and control practices related to the use of chloramines. This involved preparing an electronic survey to facili-tate questionnaire distribution and data analysis. Responses from 69 utilities were received.

For the case studies, American Water led the development of effec-tive strategies with respect to chemical feed system design, dose and application points, operator training, community education, and plant and distribution system monitoring programs.

EES led the development of several tools to transfer the information to the water industry, including a print and electronic manual, an interactive CD-ROM for the decision process on whether to switch to or optimize the chloramine process, approximately 20 detailed case studies, a design checklist, 15 to 20 example brochures related to community acceptance, and monitoring protocols, etc.

As part of this Water Research Foundation

research project, Carollo provided

guidelines to utilities for designing and

implementing chloramine treatment

systems, including various ammonia feed

systems.

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20


Consumer Perceptions of tap Water, Bottled Water, and Filtration Devices

Measurment of consumer satisfaction with tap water

quality.

Investigation of demographic trends in

consumer satisfaction and consumption of tWAs.

Identification of the factors that cause consumers to purchase and use bottled

water and POU/POe devices.

Development of a list of recommendations for water utilities that

can improve consumer satisfaction and help bridge gaps between perception and reality.

HIG

HL

IGH

TS

Recently, much attention has been given to the consumption and use of tap water alternatives (TWAs) such as bottled water and point of use/point of entry (POU/POE) devices. The water market has changed dramatically in recent years. Significant growth in public/private partnerships, intense marketing of bottled water and POU/POE devices, and the recent increase in media attention to drinking water issues have contributed to a shift in public attitudes toward tap water. Data collected in recent years reveal some interesting statis-tics, (as of 2002):

Two million POU/POEs are purchased annually in the U.S. and !

Canada.

Fourty-one percent of Americans use POU/POEs, bottled water or !

both.

Annual bottled water sales are $4 billion in the U.S. !

Satisfaction levels for both tap water and TWA drinkers were greater than 50 percent for each water quality feature examined. Tap water drinkers consistently had a higher level of satisfaction compared to TWA drinkers. For example, 92 percent of tap water drinkers were satisfied with the “overall quality” of their tap water compared to 74 percent satisfied TWA drinkers. Tap water “taste” received the fewest satisfied respondents (52 percent from TWA drinkers). In fact, TWA drinkers were three times more likely to report an “offensive” flavor (e.g., musty/earthy, metallic, or chlorinous), compared to tap water drinkers.

Consumption of TWAs varied considerably across the U.S. As few as 20 percent (Midwest market) of the local population to as many as 87 percent (West Coast market) consumed either bottled or filtered water. Sixty-eight percent of filtered water drinkers were motivated by safety. Bottled water drinkers were motivated equally by safety (28 percent), taste (30 percent), and healthiness (28 percent).

On average, utilities overrated consumers’ satisfaction levels by 15 percent in areas of tap water quality and utility service. This gap between utility managers’ perceptions of consumers’ satisfaction level and actual consumer satisfaction levels may, in part, account for the consumption trend toward tap water alternatives.

Carollo completed two Water Research

Foundation projects looking at customer

perceptions of tap water quality

and bottled and filtered water use.

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21


Changes in Distribution System Water Quality on Disinfection efficacy

Determination of target level of secondary

disinfectant to preserve microbial water quality in

distribution systems.

Use of desktop, bench-scale, pilot-scale and

full-scale technologies.

example disinfection efficiency of free chlorine and chloramines against

selected microorganisms.

HIG

HL

IGH

TS

The maintenance of a disinfectant residual in distribution systems has traditionally been used to protect microbial water quality. However, experiences reported by utilities have shown that microorganisms sur-vive in the bulk water of distribution systems despite the continuing presence of disinfectants. Such occurrences place doubt on the ability of disinfectant residuals to ensure microbial protection, especially when facing challenges such as biological regrowth, treatment failure, and breaches in distribution system integrity.

The goal of this project was to address questions concerning the usefulness of maintaining a secondary disinfectant residual and the target level to be maintained. The project involved five phases:

Phase I - Conducting a literature review on disinfection efficacy, !

surveying North American utilities to assess the primary questions presented above, and analyzing historical water quality data col-lected from selected utilities.

Phase II - Conducting a mathematical analysis of published !

microbial inactivation kinetics and proposing theoretical required minimum disinfectant concentration.

Phase III - Conducting secondary disinfectant challenge experi- !

ments to fill in gaps where published inactivation kinetics are inadequate.

Phase IV - Examining secondary disinfectant analytical limitations !

and errors, mainly the potential disinfection efficacy of organic chloramines when measuring chloramine concentration.

Phase V - Conducting bench-scale experiments using annular !

reactors and pilot-scale studies using pipe loops to determine the minimum disinfectant concentration required to sufficiently inactivate microorganisms, and correlating this concentration to various distribution system related factors.

Participating utilities included the East Bay Municipal Utility District (California), the Jordan Valley Water Conservancy District (Utah), the Halifax Regional Water Commission (Nova Scotia), the Regional Municipality of Waterloo (Ontario), Southern California Water Company (California), Seattle Public Utilities (Washington), Newport News Waterworks (Virginia).

This project involved bench-scale

experiments and pilot-scale studies

using pipe loops (above) to determine

the minimum disinfectant concentration

required to sufficiently inactivate

microorganisms.

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22

City of GlendAle, CAliforniA

Water and Power Hydraulic Model

Development of a hydraulic model for the entire water system using H2OMAP®.

Assist the City in planning and optimizing the

operation of the water distribution system.

Assist the City in meeting the Stage 2 DBPR and the IDSe requirements for an SSS in lieu of the SMP

options.

Provide the City with a calibrated hydraulic model that will become a tool for

addressing the Stage 2 D/DBPR IDSe requirements

for a well-calibrated distribution system.

HIG

HL

IGH

TS

The City of Glendale Water and Power Department retained Carollo to develop a hydraulic model of it's water distribution system. Glendale's distribution system is relatively complex, with three con-nections the Metropolitan Water District of Southern California, 13 wells, two treatment plants, interconnections with two other agen-cies, 28 pump stations, and 27 storage facilities. These facilities are organized into 11 separate pressure zones that provide water service to approximately 35,000 connections.

The main objectives of this project includes:

Providing Glendale with a hydraulic model that will assist them in !

planning and optimizing the operation of their water distribution system.

Meeting the Stage 2 DBPR and the IDSE requirements for a !

system specific study (SSS) in lieu of the standard monitoring program (SMP) option.

At the completion of this project, the calibrated hydraulic model will become a tool for addressing the proposed Stage 2 DBPR IDSE requirements for a well-calibrated distribution system model for the purpose of the SSS. This will be accomplished by accurately modeling pipelines (4 inches and larger), storage facilities, pumping stations, control valves, pressure zones, groundwater wells, supply sources, and interconnections.

Glendale’s GIS shape files containing the pipeline, storage reservoirs,

pump station, and valve layers will be imported into MWH Soft’s

H2ONET® hydraulic model software.

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23

City of AnAheiM, CAliforniA

System-Wide Disinfection Study

Behavior evaluation of planning tool for

operational strategies and capital cost development.

Distribution system modeling.

Simulations to trace water sources, monitor water

age, and evaluate ?? residuals.

evaluation of chlorinated/chloraminated water

sources.

Complex supply and storage issues.

HIG

HL

IGH

TS

The City of Anaheim retained Carollo to prepare a system-wide disinfection study to serve as a planning tool for the development of operational strategies and capital costs. Anaheim currently uses groundwater, which is chlorinated, supplemented by Metropolitan Water District of Southern California surface water, which is chloraminated. Furthermore, the topography of Anaheim’s western half is relatively flat and contains the majority of the supply wells, while Anaheim’s eastern half consists of hills and canyons and con-tains the majority of the City’s water storage facilities.

Carollo used a hydraulic water distribution system model, assembled with H2ONET® and containing over 10,000 pipes, to run water quality simulations. The team used these simulations to trace water sources and relative blends of groundwater and surface water, to monitor water age, and to evaluate disinfection residuals. The project included identifying disinfection alternatives and recommending facility improvements.

Carollo’s disinfection system study for Anaheim included an

H2ONET® distribution model involving 10,000 pipes.

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24

City of PAlo Alto, CAliforniA

Water Wells, Regional Storage, and Distribution System Study

Water master planning.

Distribution system modeling.

Capital improvement program.

Conversion of distribution system model from

Waterworks to H2Onet®.

GIS-linked model.

HIG

HL

IGH

TS

Carollo conducted a study for the City of Palo Alto to evaluate and develop recommendations to improve Palo Alto’s water wells, reser-voir storage, and distribution system. Major project tasks included:

Developing emergency scenarios and providing model analysis. !

Calibrating and updating the distribution system model to current !

conditions, providing recommended system design and analysis criteria, and preparing a capital improvement program for the recommended improvements. Carollo converted the model from Waterworks to H2ONET®.

Performing an audit to quantify the amount of unaccounted for !

water.

Evaluating storage needs to address requirements for daily opera- !

tional demands and emergency scenarios, as well as operational or facility changes to improve utilization and water quality in the foothill areas’ reservoirs.

Reviewing hydrogeologic data regarding the ground !

water sources and providing recommendations for well testing.

Providing recommendations for improving the exist- !

ing well system as a source of supply, as well as the suitability of the well field to serve as an emergency or standby supply.

Investigating the potential impacts of the proposed !

chloramine conversion on the existing distribution system.

Carollo is continuing to help Palo Alto design and implement the improvement projects. Carollo designed, and is providing construction management services for improvements to five existing pumps stations, three existing wells, and four existing reservoirs. Carollo is also performing a siting analysis, including a public involvement campaign and Environmental Impact Report (EIR) for a new 2.5-million-gallon reservoir.

Carollo has updated and calibrated Palo

Alto’s water system hydraulic model for

several purposes, including water quality

and water age modeling.

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25

CAliforniA dePArtMent of CorreCtions, sAn luis oBisPo, CAliforniA

California Men's Colony Water Distribution System Replacement

extensive hydraulic modeling of distribution

system.

Replacement of 112,000 linear feet of 6- to 18-inch-diameter water pipelines.

two booster pump stations.

Modifications to prestressed concrete

storage tanks.

environmentally-sensitive area.

HIG

HL

IGH

TS

The California Men’s Colony (CMC) is a state prison facility near San Luis Obispo, California. CMC is responsible for providing pota-ble water to CMC, Camp San Luis Obispo, the County of San Luis Obispo detention facility system, and Cuesta Community College. In all, CMC operates and maintains approximately 40 miles of distribu-tion pipelines, five storage reservoirs, two booster pump stations, and three inactive wells. The water distribution system was hastily constructed by the Corps of Engineers at the advent of World War II when Camp San Luis Obispo was developed as a regional training facility by the army.

Carollo prepared a facilities plan, including hydraulic modeling, to identify capacity and pressure deficiencies, evaluate water quality problems, and recommend improvements. Design includes replace-

ment of more than 21 miles (112,000 linear feet) of 6-inch to 18-inch diameter pipelines, improvements to two booster pump stations, storage tank modifications, new control valves, pressure-reducing valve stations, blowoff and air/vacuum relief facilities, hydrants, and reactivation of one key well. Construction methods include traditional open-cut, bore/jack crossings of State Highway 1, and horizontal directional drilling for creek crossings. The total estimated construction cost is $23 million.

Associated activities include aerial photogrammetry and topographic surveying, a geotechnical investiga-tion, a Phase I Environmental Site Assessment, and coordination of an environmental impact report. The design accommodated numerous threatened or endangered species, and included an evaluation of the potential for encountering serpentine rock (with naturally occurring asbestos).

Carollo prepared a model of the CMC

distribution system and performed a preliminary

water quality analysis of the system.

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26

City of yuMA, ArizonA

Water Distribution System Master Plan Update

new hydraulic model.

Data collection protocol.

evaluate existing and future system needs.

HIG

HL

IGH

TS The City of Yuma is experiencing significant growth in both residen-

tial and industrial water demands. In response to this growth, Carollo updated Yuma’s water distribution master plan. This study included the following primary objectives:

Building a new hydraulic model for the entire water system based !

on Yuma’s digital water atlas using H2ONET® Version 3.

Preparing a data collection protocol and assist Yuma in conduct- !

ing a detailed fluoride tracer study, including THM measurements.

Performing extended period simulations to evaluate chlorine !

residuals and THM formation, after using the results of the tracer study to perform a detailed calibration of the hydraulic model.

Building a new demand generator to project future demands based !

on customer billing information, population projections, and land use data.

Evaluating the existing system and developing recommended !

short-term improvements.

Evaluating the future water service area and developing a long- !

range water system master plan that identifies future water system requirements.

The geographical distribution of the demands within Yuma is shift-ing significantly within the pressure zones. The study also included a detailed evaluation of alternatives involving the shifting of pressure zone boundaries to allow the best utilization of existing facilities.

In addition to calibration data collection, model development involved a detailed demand analysis. This analysis was based on customer billing records which are tied to parcels though GIS. The customer billing records were evaluated to determine average annual and seasonal demand patterns throughout the study area. The cus-tomer billing records for the existing system were then tied to indi-vidual model demand nodes by aggregating parcels through a polygon analysis.

Distribution system water quality (chlorine residual and disinfection by products) was evaluated using the H2ONET® software. Carollo used a special field data collection program based on fluoride tracing for the water quality model calibration.

Carollo prepared a long-range master plan update, which included identifying required improvements, phasing of facilities, and prepara-tion of a Capital Improvements Program.

As part of the Yuma Water Distribution

Master Plan, Carollo built a new

water distribution system model that

incorporates relevant data for developing

Yuma’s capital improvement program.

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27

City of hAyWArd, CAliforniA

Water Distribution System Master Plan Update and Chloramine Conversion Study

Update of existing water master plan.

Upgrade and calibration of hydraulic model.

Analysis of the impact of chlorine conversion on the

distribution system.HIG

HL

IGH

TS Carollo updated the water master plan for the City of Hayward. The

intent of this project was to update the master plan to account for recent upgrades to the water distribution system, prepare for the buildout development plans, and evaluate various water supply and water quality issues such as a conversion from chlorine to chloramine disinfection.

This project began with updating the land use and water demand projections for the buildout year of 2020. Carollo worked with Hayward to obtain the latest information on proposed development plans that included various in-fill projects, as well as a very large resi-dential and golf course community development. Using a combina-tion of historical water demand data, data from neighboring agencies, and water use estimates from the land developers, Carollo updated Hayward’s water demand projections through buildout.

Carollo used the updated water use estimates and the information on recent system upgrades to update the hydraulic model of Hayward’s water distribution system. Carollo also used this information to evalu-ate the capacity of Hayward’s ten existing/proposed water pump sta-tions and 13 existing reservoirs and to provide an initial assessment of where pump station and reservoir capacity upgrades were needed.

After calibration, Carollo used the computer model to evaluate the performance of the water distribution system and refine the pump station and reservoir capacity recommendations to better meet Hayward’s operational needs, such as time-of-use pumping.

Hayward purchases water from the San Francisco Public Utilities Commission. In preparation for SFPUC’s conversion from chlorine to chloramine disinfection, Carollo examined the potential impacts of the conversion on the distribution system. Carollo used Hayward’s updated distribution system model to identify potential problem areas, as well as operational schemes to reduce water age. The results of this effort included a revised operational plan focused on maintain-ing high distribution system water quality without impacting system operations, and a water quality monitoring and action plan focused on preventing nitrification episodes.

The water master plan update summarized the recommended improvements to address the identified deficiencies and addressed issues related to water supply, pump station and storage capacity, emergency preparedness, system capacity to meet fire flows, and water quality.

Carollo’s identifed both capital and

operational changes to cost effectively

address Hayward’s future needs.

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28

MetroPolitAn WAter distriCt of southern CAliforniA, los AnGeles, CAliforniA

Preliminary Design for the Cross-Connection Prevention Program

Relocation of air release valves and air-release/

air-vacuum valves to an above ground location.

Modifications to the underground

discharge piping of blowoff assemblies

to eliminate potential cross-connections.

Preparation of estimates of probable construction

costs.

Preliminary evaluation of alternative above ground enclosures to minimize

aesthetic impacts.

HIG

HL

IGH

TS

The Metropolitan Water District of Southern California has imple-mented a cross-connection prevention program to protect its treated water supply system from potential contaminants, and to meet California Code requirements. The program includes corrections and modifications to potential cross-connection structures on the MWDSC treated water distribution systems in Southern California, including air release valves, air-release/air-vacuum valves, blowoffs, and air stacks.

Among the 1,360 potential cross-connection structures identified by MWDSC, Carollo worked with the MWDSC team and provided engineering services to prepare preliminary design drawings for 413 structures located across Southern California. Carollo prepared pre-liminary design plans and sections for the modifications/relocation of the air release valves, air-release/air-vacuum valves, and blowoffs in sizes varying from 1.0 to 12 inches in diameter.

At MWDSC’s request, Carollo pre-pared a preliminary construction cost estimate for 338 structures based on the preliminary design drawings and avail-able field information. The cost estimate considered various site-specific factors and constraints to allow MWDSC to refine earlier planning-level estimates. A subsequent independent cost estimate prepared by a local contractor confirmed Carollo’s cost estimate.

Carollo completed preliminary engineering work on the cross-

connection prevention program in eight months–approximately four

months earlier than the initial 12-month project design schedule–in

order to accommodate MWDSC’s program.

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29

southern nevAdA WAter Authority, lAs veGAs, nevAdA

South Valley Lateral, Air Release, and Air Vacuum Valve Modifications

Modification of 28 AR&AVV assemblies to add hard piping to vents

above-grade.

Minimization of the possibility of cross-

contamination from water collecting in the vault.H

IGH

LIG

HT

S The Southern Nevada Water Authority (SNWA) found that con-struction of the South Valley Lateral a 90-inch to 120-inch diameter water transmission pipeline included the installation of air valves in vaults with standard vent bonnets. This is a deviation from their Facility Engineering Guides, which require air valves in vaults to include hard pipes to vents above grade. This deviation in the instal-lation was apparently caused by restricted headroom in the vaults. The original construction contracts were closed prior to the time of the review by SNWA.

Besides providing the normal air valve duties, the purpose of the hard piping is to minimize the possibility of cross-contamination from water that might collect in the vault over a period of time and eventually submerge the air valve. If the air valve was not hard piped, there is a chance that contaminated water could enter the potable water supply system.

Carollo was asked to review the existing air valve installations and comment on the plans for modifications that were prepared by the three original design firms. The plans for modifying the air release/air vacuum valves (AR&AVVs) were then included in a project for which Carollo was responsible for design and construction phase services.

Air valves will be modified to include hard

piping to vents above ground level to

eliminate potential cross-contamination.

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PAx sCientifiC, inC.

Innovative Reservoir Mixing technology Validation

Highly effective reservoir mixing technology.

Identification and validation of a novel

approach to an emerging problem.

Low-cost, effective distribution system water

quality maintenance.

Potable water reservoirs are typically kept greater than 70 percent full at all times to maintain a source of water for fighting fires and other water supply emergencies. Water stored in reservoirs tends to warm due to the heat from the sun and rises toward the top of the tank. The cool and warm waters tend not to mix—a condition known as thermal stratification. As a result, the water at the top of the tank tends to age with time, leading to low disinfectant residuals. In the case of chloraminated distribution systems, these reservoirs can become sources of nitrification.

To combat this issue, many water utilities are modifying their reser-voirs to include water mixing capabilities. Potential solutions include separating the inlets and outlets, installing check valves, or adding mechanical mixers. Each of these systems has varying costs, benefits, implementation issues, and effectiveness.

Carollo is continually seeking ways to bring novel, creative, and improved solutions to our clients, especially when these improve-ments provide benefits at lower costs and reduced environmental impact. PAX Scientific, Inc. is an industrial design firm that has translated nature’s flow efficiencies into streamlined design geom-etries for equipment such as fans and pump impellers. Carollo and

PAX have explored opportunities to use the PAX technology to benefit the water and wastewater treatment industry, and chose reservoir mixing as the first application to verify and validate its efficacy.

Carollo devised a series of tests that studied disruption of thermal stratification in drink-ing water reservoirs and conducted these tests in 1-million-gallon, 2.5-million-gallon, and 4.0-million gallon ground-set, welded steel tanks. PAX installed its mixer at the bottom of each tank using a simple stainless

steel tripod stand for support. A 110-volt outlet located in a pump station at each tank site supplied power. Carollo ran the reservoir mixing tests for six weeks, testing different power requirements, impeller rotation direction, and repeatability of the test results.

Test results indicated that the PAX-designed impeller provided reli-able mixing at very low power requirements. In the 4.0-million-gal-lon reservoir for example, a temperature stratification of 4 degrees Celsius was reduced to 1 degree Celsius using between 100 and 150 watts power.

HIG

HL

IGH

TS

The 6-inch impeller used to mix a

2.5-million-gallon reservoir.

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Tem

pera

ture

(deg

C)

Surface3 feet deep12 feet from bottom2 feet from bottom

Mixer Off Mixer On

Continuous temperature data, from probes located at four different

depths, illustrate that the mixer disrupted thermal stratification in a

1-million-gallon reservoir.

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Carollo owns bench- and pilot-scale testing equipment that can be used to evaluate different distribution system conditions in paral-lel. This equipment can be used to examine treatment schemes and

their effect on the distribution system, and includes pre-oxidation skids, rapid mixers, flocculation tanks, settling tanks, intermedi-

ate ozonation systems, filtration columns, UV disinfection systems, and membrane treatment systems. A detailed description of this testing equipment is summarized in Carollo’s specialty SOQ on Capabilities for Pilot- and Bench-Scale Testing.

The testing capabilities summarized below are strictly related to distribution system simulations through bench-

scale testing and hydraulic modeling.

BenCH-SCALe tReAtMent CAPABILItIeS

Simulated Distribution System testing

Simulated distribution system testing (SDS) testing can simulate water age in distribution systems in a simple manner. However, these simulations are conducted in amber glass bottles, and the effect of distribution system pipe materials and hydraulics are not assessed. In the SDS test, variables include final disinfection pH; incuba-tion time (average or maximum residence time in the distribution system); incubation temperature; and disinfectant type (chlorine, chloramines); dose; and target residual. Conditions are selected to be as closely related as possible to actual distribution system condi-tions. If temperature is an issue, repeat seasonal sampling and testing are recommended. Before and after the incubation period, samples are collected and analyzed for the desired parameters (e.g., disinfec-tant residuals, DBPs, microorganisms, etc.). SDS results can then be compared to actual distribution system results.

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Annular Reactors

Carollo maintains BioSurface Technologies annular reactors for con-ducting distribution system studies. These reactors have the unique capability of allowing separate control of the detention time and shear stress within the system. The reactors consist of a rotor turning inside a stationary outer cylinder. Hydraulic conditions within the reactor, such as shear stress and water velocity, depend on the rota-tional speed of the rotor. A rotational speed of 50 rpm is commonly used in drinking water studies, as it creates a shear stress of 0.25 N/m2 at the outer wall, which corresponds to a flow of approxi-mately 1 foot per second (0.3 meters per second) in a 4-inch-diam-eter (100 mm) smooth pipe. Four draft tubes inside the inner cylinder enhance liquid mixing.

The reactors allow the collection of both water samples and coupons from which biofilm growth and the extent of corrosion may be deter-mined. Polycarbonate coupons are often used to evaluate biofilm growth without the presence of corrosion or corrosion by-products. Coupons manufactured from common pipe materials such as ductile iron may also be used. The influent flow rate determines the water residence time inside the reactor, simulating the residence time in the distribution system.

In most bench-scale experiments, the reactor is assumed to approxi-mate a finite section of a distribution system. A common set up for drinking water experiments consists of pumping the test water into the annular reactor. Test waters may be augmented by adjust-ing water quality parameters such as pH or the level of background organic material, or seeded with specific consortia of microorganisms. Additional nutrients, disinfectants, corrosion inhibitors, or other constituents may also be pumped into the reactor depending on the specific experimental objectives.

Annular reactors may also be used in combination with batch incu-bation bottles to differentiate the effect of the pipe wall from the effect of water age. For batch incubation, a clean bottle is filled with reactor influent water. The bottle is kept under the same conditions of temperature and darkness as the reactors. After a period of time equivalent to the reactor residence time, water is sampled from the incubation bottle and from the reactor effluent. A comparison of the results allows the impact of biofilm growth and corrosion at the pipe wall to be distinguished from the effect of water age.

The reactors are readily transportable, and can be shipped along with other required equipment such as control unit, a feed water pump, and chemical dosing pumps.

Carollo has used the annular reactors to evaluate the effectiveness of scale inhibitors for preventing scale formation in a reverse osmosis

Carollo's annular reactor studies

permit independent control of

detention time and shear stress,

require small sample volumes,

and allow pipe wall corrosion and

biofilm growth to be quantified

in addtion to water quality

perameters.

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brine disposal pipeline. These reactors have also been used to evaluate biofilm formation and regrowth in distribution systems with varying levels of available biodegradable organic matter.

Hydraulic and Water Quality Models

Computer-aided hydraulic modeling is a powerful tool in all aspects of water distribution system planning, design, operation, and water quality analysis. Carollo uses a variety of state-of-the-art commer-cially available hydraulic modeling software including: H2ONET, H2OMAP Water, InfoWater, WaterCAD, WaterGEMS, EPANET, and others. Geographic information system (GIS) tools such as

the ArcGIS Family, and Autodesk Map, are used to optimize the development and data management of hydraulic models.

The assembled hydraulic models provide insights for optimizing the operation of existing distribution systems, identifying expansion needs to service future developments, and analyzing water quality. Carollo’s approach emphasizes the role of hydraulic and water quality calibration in establishing a level of confidence in the hydraulic models. The calibration is performed to verify the model is simulating current field condi-tions.

Reservoir Water Quality and thermal Stratification testing

Most potable water distribution systems are built with water storage reservoirs distributed in various locations of the service area. These reservoirs store water to be supplied to the system during times of high water demand (e.g., peak daily demands or for fighting fires) and when the water system has been disrupted.

Potable water reservoirs are usually kept greater than 70 percent full at all times to maintain a source of water for fighting fires and other water supply emergencies. Water stored in reservoirs tends to warm due to the heat from the sun and rises toward the top of the tank.

Application table

Parameter Value and Notes

Reactor Volume, each 1,150 mL

Typical Range of Pipe Detention Times Simulated 2 hours to 1 week

Typical Range of Rotational Speeds 50 to 250 rpm

Electrical Requirements Single-phase, 120-V, 60 Hz

Typical Rental Fee $300 per month

Carollo uses a variety of state-of-the-art

hydraulic modeling software, coupled

with GIS, to help optimize the operation of

distribution systems.

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The cool and warm waters tend not to mix—a condition known as thermal stratification. As a result, the water at the top of the tank tends to age with time, leading to low disinfectant residuals. In the case of chloraminated distribution systems, these reservoirs can become sources of nitrification.

Carollo possesses the equipment and experience needed to identify and evaluate thermal stratification in drinking water reservoirs. For example, we tested the validity of a novel reservoir-mixing device at the Santa Clarita Water Company. Our test entailed measuring thermal stratification in 1-million-gallon, 2.5-million-gallon, and 4.0-million gallon ground-set, welded steel reservoirs. We installed strings of HOBO Water Temp Pro remote automatic recording temperature probes to monitor temperature trends at various depths and loca-tions in the reservoirs. We also verified the reservoir temperature data using a highly accurate, handheld meter that was lowered into the reservoirs at specific times to provide additional data on thermal stratification and the effectiveness of the reservoir mixer. The energy usage of the mixing device and the air temperature outside the res-ervoirs was also recorded. The results of this testing showed that the reservoirs would exhibit 6 degrees Celsius of thermal stratification on warmer days without mixing, and that the novel mixer would disrupt this stratification in about 12 hours using about 150 watts of power.

Coupled with our expertise and experience in distribution system modeling, which we use to identify reservoirs that are likely to have

high water age, our reservoir testing capabilities provide Carollo’s clients with valuable information for maintaining the highest level of distribution system water quality possible.

Common Inlet/Outlet

Thermally Isolated Top Layer

ThermoclineCool Bottom Layer

Water Surface

Carollo has the equipment and experience to identify and evaluate

thermal stratification in drinking water reservoirs and can assist

clients with mitigation measures.

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SELECT DISTRIBUTION SYSTEM PUBLICATIONS - PEER-REVIEWED1 Mackey, E.D., Baribeau, H., Crozes, G.F., Suffet, I.H., and Piriou, P.H. “Public Thresholds for

Clorinous Flavors in US Tap Water,” International Water Association Water Science and Technology Journal, 9:49, 337-342. 2004.

2 Mackey, E.D., Baribeau, H., Fonseca, A.C., Davis, J.E., Brown, J.C., Boulos, L., Crozes, G.F., Piriou, P., Rodrigues, J.M., Fouret, M., Bruchet, A., and Hiltebrand, D. “Public Perception of Tap Water Chlorinous Flavor,” American Water Works Association Research Foundation and American Water Works Association, Denver, CO. 2004.

3 Crozes, G.F., and Cushing, R.S. Evaluating Biological Regrowth in Distribution Systems. American Water Works Association Research Foundation, Denver, CO, 2002.

4 Mackey, E.D., Davis, J.E., Boulos, L., Brown, J.C., and Crozes, G.F. “Consumer Perceptions of Tap Water, Bottled Water and Filtration Devices,” American Water Works Association Research Foundation, Denver, CO. 2002.

SELECT DISTRIBUTION SYSTEM PUBLICATIONS-OTHER1 Kraska, D.J., and Pozos, N.L. “Chlorine or Chloramine? Know the Facts Before Making the Decision.”

Paper presented at the American Water Works Association 2003 Water Quality Technology Conference, Philadelphia, PA, November 2-5, 2003.

2 Giese, N.L., and Kraska, D.J. “Development of a Simplified Nitrification Monitoring Program.” Paper presented at the California-Nevada Section of the American Water Works Association 2003 Annual Fall Conference, San Diego, CA, October 6-10, 2003.

3 Acker, C.L., and Kraska, D.J. “Operation and Maintenance of Water Distribution Systems During and After Conversion to Chloramine Disinfection.” Paper presented at the American Water Works Association 2001 Annual Conference & Exposition, Washington, D.C., June 16-21, 2001.

4 Oxenford, J., Cushing, R., and Crozes, G.F. “Evaluation and Control of Biological Regrowth.” Proceedings of the American Water Works Association Water Quality and Technology Conference, San Diego, CA, 1998.

5 Pozos, N.L., and Kraska, D.J. "Development of a Simplified Nitrification Monitoring Program." Paper presented at the California-Nevada Section of the American Water Works Association 2003 Annual Fall Conference, San Diego, CA, October 6-10, 2003.

6 Baribeau, H., Boulos, L., Pozos, N., Crozes, G.F., Gagnon, G.A., Rutledge, S., Skinner, D., Hu, Z., Hofmann, R., Andrews, R.C., Wojcicka, L., Alam, Z., Chauret, C., Andrews, S.A., Dumancic, R., Warn, E. “Impact of Distribution System Water Quality on Disinfection Efficacy,” American Water Works Association Research Foundation, Denver, Colorado, 2005.

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WATER AND WASTEWATER EXPERTSCarollo is an environmental engineering firm specializing in the planning, design, and construction of water and wastewater facilities and infrastructure. Carollo’s reputation is based upon client service, a continual commitment to quality, and technical leadership.

During our 86-year history, Carollo has successfully completed more than 25,000 projects for public sector clients. Carollo is currently ranked within Engineering News Record's top 500 design firms. More importantly, ENR’s annual Source Book ranks Carollo among the top 10 firms for water and wastewater treatment plant design. Unlike many of our competitors, Carollo provides only water and wastewater engineering services.

With our focus on water and wastewater, we recruit nationwide and hire technical staff who have the extensive background and train-ing specific to this field. For that reason, the quality and professional standing of our core group of water and wastewater professionals equals or exceeds that provided by some of the largest engineering firms in the U.S.

Resources

Carollo’s staff numbers more than 1,050 employ-

ees, including more than 500 registered engineers. We are

a full-service water and waste-water engineering company with the experience and qualified

professionals to successfully manage projects of any size. Our staff includes

civil, sanitary, electrical, environmen-tal, mechanical, chemical, structural,

instrumentation, and corrosion con-trol engineers, as well as architects,

planners, and specialists in other areas. These individuals perform work solely on water and wastewater related facilities.

Carollo is currently

ranked within Engineering

News Record's top 500 design

firms . . . ENR's annual Source

Book ranks Carollo among the

top 10 firms for water

and wastewater treatment

plant design.

UsmapWaterProj-CoProf-Red.ai (Text list for this map is on V:\CompanySOQs\GeneralWtr&WWSOQ\Sections\03WtrTreatment\CaliforniaWaterMap.doc)

Carollo has engineered water

projects across the country.

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Carollo’s state-of-the-art computer

network allows us to effectively

communicate between offices and

interface with almost any engineering

software on the market today.

MANAGEMENT PHILOSOPHYCarollo’s management philosophy and the success of our company are founded on simple precepts:

! Seek out, hire, and hold onto the best people in the business. We recognize that the most critical element for a suc-cessful project is the project team. Carollo aggressively recruits the top candidates from the leading engineering schools across the country. We train and mentor these engineers

to become the next generation of leaders for Carollo and the industry. This long-term com-

mitment to developing excellent engineers has resulted in a depth of talent unmatched by other

consulting firms.

! Specialize in the planning, design and construction management of water and wastewater projects. This is our busi-ness. Our success hinges solely upon our ability to provide respon-sive service to our municipal clients.

! Commit our partners to an active role in every project. This provides our clients with top management interest, clear account-ability, responsiveness, and talent—and helps to ensure that the necessary staff and resources are committed to each assignment.

! Focus on client service. Carollo knows the value of listening to our clients and recognizes that successful projects result from the combined expertise of our staff and the client’s staff. This commitment to understanding client needs and valuing their input is one of the cornerstones of Carollo’s success.

LEADERS IN WATER ENGINEERINGCarollo has provided design and construction management services for more than 100 water treatment plants with a total capacity of more than 3.5 billion gallons per day, more than 1,000 miles of water pipeline ranging in size from 6 to 108 inches in diameter, and more than 100 water pumping stations with capacities as high as 600 mgd. We have recently completed or are performing ongoing water projects for many of the country’s major municipalities or special districts. A few examples of Carollo’s achievements include:

! Conceiving and developing the custom design approach for low-pressure membrane water treatment plant design. Carollo devel-oped our own custom, nonproprietary, non-packaged pilot plant unit, which has been successfully tested in Kansas City, MO.

Carollo provides only water

and wastewater engineering

services, resulting in a level of

understanding of key project issues

that few can match.

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! Engineering the fast-paced design/build expansion of the Palm Coast, FL, reverse osmosis (RO) water treatment plant from 3.2 to 9.6 mgd. Carollo completed preliminary design and obtained all permits just eight weeks after beginning work to help facilitate successful completion of this project in just 15 months.

! Conducting the first U.S. testing and evaluation of electrodialysis reversal (EDR) for perchlorate treatment.

! Achieving leadership in ultraviolet (UV) disinfection, first for wastewater applications in the western United States and now for UV drinking water applications. Carollo was the primary author of the USEPA UV Disinfection Guidance manual. We also developed and operate the world's largest UV validation facility in Portland, OR.

! Designing the preozonation and intermediate ozonation at two water treatment facilities for the City of Arlington, TX, using our computational fluid dynamic (CFD) modeling to optimize ozone contactor design. Carollo also conducted a joint research project with various utilities in the Phoenix, AZ, area to evaluate ozonation and biological filtration to meet long-term finished water quality goals, leading to design and construction of ozonation facilities in Gilbert and Peoria, AZ.

! Designing, in a joint venture, the world’s largest ozone generation system at a water treatment facility in Las Vegas, NV.

FORMULA FOR SUCCESSMuch of our success as an industry leader is based on our ability to

offer advanced solutions that are practical, affordable, and reliable. We strive to maximize the use of existing infrastructure whenever possible, promote environ-mental conservation, and make the best technologies available at a competitive cost.

A major factor in maintaining Carollo's ability to inte-grate new technology is the Carollo Water Research Group (CWRG). The relationship between our design engineers and the CWRG is unique in the industry and serves as a company-wide resource for evaluating water quality and treatability data, performing pilot studies, developing design criteria, tailoring design solutions to

water quality issues, and addressing regulatory compliance concerns.

Our client list includes the following:

! City of Phoenix, AZ

! East Bay Municipal Utility District, Oakland, CA

! Metropolitan Water District of Southern California

! Sacramento Regional County Sanitation District, CA

! City of San Diego, CA

! City and County of San Francisco, CA

! City of Sacramento, CA

! Denver Water Department, CO

! City of Minneapolis, MN

! Kansas City, MO

! City of St. Louis, MO

! City of Las Vegas, NV

! Southern Nevada Water Authority, NV

! City of Arlington, TX

! City of Austin, TX

! Upper Trinity Regional Water District, TX

Carollo designed the 624-mgd Alfred Merritt

Smith Water Treatment Plant ozone contactor

for the Southern Nevada Water Authority. It is

the world's largest ozone system at a water

treatment facility.

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Our firm takes pride in the large number of clients with whom we have maintained continuing working relationships. We have worked with some clients for more than 80 years—a clear indication of the quality of our work, our control of costs, and our ability to meet schedules. This dedication to quality has resulted in a long list of suc-cessful projects and satisfied clients, some of which are highlighted in the table below.

Cap

acity

(m

gd)

Con

vent

iona

l Tre

atm

ent

Mem

bran

esO

zone

UV D

isin

fect

ion

Aut

omat

ion

Solid

s H

andl

ing

Che

mic

al H

andl

ing

Project Elements

Client/Project

Southern Nevada Water Authority, Las Vegas, Nevada - Southern Nevada Water System Improvements Project

624 l l l l l

City of Phoenix, Arizona - Val Vista Water Treatment Plant 220 l l l l

City of Phoenix, Arizona - Union Hills Water Treatment Plant 160 l l l l

City of Sacramento, California - E.A. Fairbairn Water Treatment Plant 160 l l l l

City of Sacramento, California - Sacramento River Water Treatment Plant

160 l l l l

Metropolitan Water District of Salt Lake City and Sandy, Utah - Point of the Mountain Water Treatment Plant

150 l l l l l l

City of Oklahoma City, Oklahoma - Draper Water Treatment Plant 150 l l l l

East Bay Municipal Utility District, California - Walnut Creek Water Treatment Plant

120 l l l l l

Santa Clara Valley Water District, California - Santa Teresa Water Treatment Plant

100 l l l l

Santa Clara Valley Water District, California - Rinconada Water Treatment Plant

75 l l l l

City of Arlington, Texas - Pierce-Burch Water Treatment Plant 68 l l l l

City of Arlington, Texas - John F. Kubala Water Treatment Plant 65 l l l l

Santa Clara Valley Water District, California - Penitencia Water Treatment Plant

42 l l l l

City of Vallejo, California - Fleming Hill Water Treatment Plant 42 l l l l l

Town of Gilbert, Arizona - Gilbert Water Treatment Plant 30 l l l l

City of Peoria, Arizona - Greenway Water Treatment Plant 16 l l l l l

Upper Trinity Regional Water District, Texas - Tom Harpool Water Treatment Plant

16 l l l l

Brazos River Authority, Texas - Brazos River Authority Water Treatment Plant

15 l l l

City of Lake Forest, Illinois - Lake Forest Water Treatment Plant 14 l l l l

City of Neenah, Wisconsin - Neenah Water Treatment Plant 12 l l l l

United Water Missouri - United Water Missouri Treatment Plant 8 l l

City of South Bend, Washington - South Bend Water Treatment Plant 2 l l l

Representative Water Treatment Projects

Documents

ULQNLQJ :DWHU...the IDSE, as part of the Stage 2 D/DBPR. The USEPA used the study findings to finalize the Stage 2 D/DBPR. Study results have also been published in the AWWA manual: