Team 19 Project Proposal and Feasibility Study

Mark De Haan Jeremy Kamp

Nathan Laframboise Julie Swierenga Wendy Tabler

Engineering 339/340: Senior Design Project

Calvin College

8 December 2014

Copyright © 2014, Calvin College, Mark De Haan, Jeremy Kamp, Nathan Laframboise, Julie Swierenga, and Wendy Tabler

EXECUTIVE SUMMARY The ACE team will design a water distribution system for the city of Apatug, Ecuador, with assistance from Bruce Rydbeck, the project client. Currently, Apatug’s water is supplied by a 110 millimeter diameter polyvinyl chloride (PVC) feed line. This line runs 7 kilometers from protected springs at 4360 meters elevation to deliver water to the community at 3339 meters. The team’s water distribution system design will include disinfection of source water using a liquid hypochlorite dosing system with a nonelectric fluid-driven injector pump. Water will then be delivered and will deliver water to the 500 homes in the community using a pipe network with various sizes of PVC pipe. With an elevation difference of 190 meters from the highest to the lowest home, Apatug presents a challenge in delivering water to each home at pressures between 20 and 60 meters of pressure. The team plans to address this challenge using five storage reservoirs at tactically chosen locations to create pressure zones. These pressure zones will be used to control pressures for homes at different ranges of elevation. Elevation data was acquired through a survey performed by an Ecuadorian engineer Cesar Cortez. Using this survey data, the team was able to model the houses and elevations in EPANET. With EPANET, the team has modeled the entire pipe network complete with storage tanks and pressure reducing valves.

In January, the team will travel to Apatug to meet with the community, collect survey data, visit neighboring distribution systems, and perform chemical analysis and water quality testing. The trip will inform future design decisions, including the final layout of the distribution system and the design of the chlorine dosing system. A bench scale study will also be implemented following the trip to investigate the effectiveness of selected injector pumps. This Project Proposal and Feasibility Study investigates design alternatives, design norms, project criteria, and project goals, providing a preliminary distribution design and an affirmation of the feasibility of the project.

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Table of Contents Table of Contents ........................................................................................................................................... i

Table of Figures ........................................................................................................................................... iv

Table of Tables ............................................................................................................................................ iv

1. INTRODUCTION .................................................................................................................................... 1

1.1 Senior Design Background ................................................................................................................. 1

1.1.1 Calvin Engineering Program ........................................................................................................ 1

1.1.2 Senior Design Class ..................................................................................................................... 1

1.1.3 Team Members ............................................................................................................................ 1

1.2 Project Background ............................................................................................................................. 3

1.2.1 Project Summary .......................................................................................................................... 3

1.2.2 Location: Apatug, Ecuador .......................................................................................................... 3

1.2.3 Current Water Situation ............................................................................................................... 5

1.2.4 The Client ..................................................................................................................................... 8

1.2.5 The Project ................................................................................................................................... 8

2. PROJECT MANAGEMENT .................................................................................................................... 9

2.1 Team Organization .............................................................................................................................. 9

2.2 Schedule .............................................................................................................................................. 9

2.3 Budget ................................................................................................................................................. 9

2.4 Method of Approach ......................................................................................................................... 10

3. PROJECT OVERVIEW ......................................................................................................................... 11

3.1 Purpose and Objectives ..................................................................................................................... 11

3.1.1 Distribution ................................................................................................................................ 11

3.1.2 Chlorination ............................................................................................................................... 11

3.2 Design Constraints ............................................................................................................................ 12

3.3 Design Criteria .................................................................................................................................. 12

3.3.1 Disinfection Method .................................................................................................................. 12

3.3.2 Disinfection Dosing ................................................................................................................... 13

3.4 Design Norms ................................................................................................................................... 13

3.4.1 Cultural Appropriateness ........................................................................................................... 13

3.4.2 Transparency .............................................................................................................................. 13

3.4.3 Justice ......................................................................................................................................... 14

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3.5 Design Alternatives ........................................................................................................................... 14

3.5.1 Distribution Pressure Control ..................................................................................................... 14

3.5.2 Distribution Pressure Zones ....................................................................................................... 14

3.5.3 Distribution Design Approach ................................................................................................... 17

3.5.4 Form of Chlorine Disinfection ................................................................................................... 17

3.5.5 Chlorine Dosing System ............................................................................................................ 18

4. INITIAL RESEARCH ............................................................................................................................ 19

4.1 Distribution System .......................................................................................................................... 19

4.1.1 Importance of Community Ownership....................................................................................... 19

4.1.2 Typical Costs by Usage.............................................................................................................. 20

4.1.3 Standard Design Values ............................................................................................................. 22

4.1.4 Household Connections ............................................................................................................. 22

4.2 Disinfection ....................................................................................................................................... 23

4.2.1 Republic of Ecuador Disinfection Policy ................................................................................... 24

4.2.2 Chlorine Alternatives ................................................................................................................. 24

4.2.3 Dosing Alternatives.................................................................................................................... 26

4.3 Available Materials ........................................................................................................................... 27

4.4 Water Reservoir Design .................................................................................................................... 27

5. WATER SYSTEM MODEL DEVELOPMENT .................................................................................... 29

5.1 Software ............................................................................................................................................ 29

5.1.1 EPANET .................................................................................................................................... 29

5.1.2 Civil 3D to EPANET ................................................................................................................. 29

5.2 Materials and Properties ................................................................................................................... 29

5.3 Design Values ................................................................................................................................... 29

5.4 Design Approach .............................................................................................................................. 30

5.5 Future Design Testing ....................................................................................................................... 33

5.5.1 Current Design ........................................................................................................................... 33

5.5.2 Possible Changes to Design ....................................................................................................... 33

6. CHLORINATION BENCH STUDY...................................................................................................... 35

7. TRIP TO ECUADOR ............................................................................................................................. 36

7.1 Trip Goals ......................................................................................................................................... 36

7.2 Tentative Itinerary ............................................................................................................................. 36

7.3 Water Testing Plan ............................................................................................................................ 37

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7.3.1 Purpose ....................................................................................................................................... 37

7.3.2 Objectives .................................................................................................................................. 37

7.3.3 Key Parameters .......................................................................................................................... 37

7.3.4 Field Test Plan ........................................................................................................................... 39

8. PROJECT FEASIBILITY CONCLUSION ............................................................................................ 41

8.1 Cost Analysis .................................................................................................................................... 41

8.1.1 Distribution System Cost ........................................................................................................... 41

8.1.2 Chlorination Dosing System Cost .............................................................................................. 41

8.2 Sustainability Study .......................................................................................................................... 42

8.3 Distribution System Design .............................................................................................................. 43

8.4 Proposed Chlorination System .......................................................................................................... 44

9. BASIS OF DESIGN ............................................................................................................................... 46

9.1 Distribution System Design .............................................................................................................. 46

9.2 Chlorination System Design ............................................................................................................. 47

9.3 Chlorination Bench Scale Study ....................................................................................................... 47

9.4 Future Work ...................................................................................................................................... 47

10. AKNOWLEDGEMENTS ..................................................................................................................... 48

11. REFERENCES ..................................................................................................................................... 49

Appendix A – Gantt Chart ............................................................................................................................ 1

Appendix B – Disinfection Decision Matrices ............................................................................................. 1

Appendix C – Pressure Zone and Tank Mathcad and Excel Calculations .................................................... 1

Appendix D – Injector Pump Specifications for MixRite and Dosmatic® ................................................... 1

Appendix E – Distribution System Schematic .............................................................................................. 1

Appendix F – Chlorine Dosing Station Schematic ....................................................................................... 1

Appendix G – Chlorine Dosing Mathcad Calculations................................................................................. 1

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Table of Figures Figure 1. The ACE Team: Jeremy Kamp, Mark De Haan, Nathan Laframboise, Julie Swierenga, and

Wendy Tabler (Photo courtesy of John Sherwood) ...................................................................................... 2

Figure 2. Location of Apatug, Ecuador, Indicated by the Red Placemark .................................................... 4

Figure 3. Terrain Map of Apatug, Ecuador ................................................................................................... 5

Figure 4. Protected Spring Collector Details, Plan View [50] ...................................................................... 6

Figure 5. Protected Spring Collector Details, Section View [50] ................................................................. 7

Figure 6. Piezometric Head Diagram in a Hydraulic System (sketch by Julie Swierenga). ....................... 15

Figure 7. Five Pressure Zone System.......................................................................................................... 16

Figure 8. Percent of rural population with access to improved water source in Ecuador, United States [11]

.................................................................................................................................................................... 19

Figure 9. Picture of a Typical Spigot [2] .................................................................................................... 23

Figure 10. Schematic of Chlorine Electrolysis to Produce Chlorine Gas. [30] .......................................... 25

Figure 11. Pressures in system under average day flows ............................................................................ 31

Figure 12. Pressures in system under 20-year peak hour flows .................................................................. 32

Figure 13. Representation of Pressure Variation due to Different HGL's .................................................. 34

Figure 14. Bench Scale Design ................................................................................................................... 35

Figure 15. Schematic of a Secchi Disk as a Turbidity Measurement [46] .................................................. 38

Figure 16. Process Flow Diagram for Chlorine Dosing. ............................................................................. 44

Figure 17. EPANET Model of Apatug with Elevations ............................................................................. 46

Table of Tables Table 1. Church's Method typically used for design of rural water systems in Ecuador [10] .................... 17

Table 2. Typical values for marginal costs of water supply [16] ................................................................ 21

Table 3. Water Testing Equipment and Cost Estimates. ............................................................................. 40

Table 4. Preliminary Pipe Lengths Estimate ............................................................................................... 41

Table 5. Unit Cost of Similar Projects [49] ................................................................................................ 41

Table 6. Preliminary Dosing System Cost Estimate ................................................................................... 42

Table 7. Summary of Distribution System Components ............................................................................ 47

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1. INTRODUCTION

1.1 Senior Design Background

1.1.1 Calvin Engineering Program

The Calvin Engineering Program is a program that has been accredited by the Accreditation Board of

Engineering and Technology (ABET). The Calvin Engineering Program seeks to shape engineering

students to apply their Christian faith to future practice while using their liberal arts background to

become well-rounded professionals. The Calvin Engineering Program also aids students in finding

summer internships and provides opportunities for students to study abroad in such locations as Germany,

the Netherlands, Kenya, China, and Cambodia. Through all these opportunities, the Calvin Engineering

Program works toward its mission statement: to “equip students to glorify God by meeting the needs of

the world with responsible and caring engineering.” [1]

1.1.2 Senior Design Class

This design project is a major component of the Calvin Engineering Department’s capstone class, Senior

Design, which is comprised of two classes: ENGR 339 in the fall and ENGR 340 in the spring. The

classes combined total 6 credit hours and are a combination of in-class lectures as well as designated

project work hours. The goal of the fall semester is project development and feasibility, and the spring

focuses on project implementation. Calvin’s Senior Design class empowers engineering students to

integrate design norms and a Christian worldview into their projects while implementing the technical

skills they have learned in their past four years of college. This experience then prepares the students for

thoughtful and significant future careers.

1.1.3 Team Members

The members of Team 19, pictured in Figure 1, are all seniors majoring in engineering at Calvin College

in the civil/environmental concentration. Each member of the team has unique interests, skill sets, and

experiences to bring to the project, and several of the team members have participated in international

projects related to water distribution. All of the team members have a passion for water resources and

hydraulic engineering, and they are committed to using their skills and education to work with the

community of Apatug to design a sustainable water distribution system that delivers clean water to the

members of the village.

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Figure 1. The ACE Team: Jeremy Kamp, Mark De Haan, Nathan Laframboise, Julie Swierenga, and Wendy Tabler

(Photo courtesy of John Sherwood)

Mark De Haan

Mark De Haan is from Zeeland, Michigan (Feel the Zeel!). Mark is particularly interested in the water

resources aspect of the civil concentration. In his free time, Mark works for the Sports Information

Department at Calvin and enjoys writing game recaps and broadcasting for a wide variety of sports. Mark

also enjoys watching professional sports, and unfortunately, he grew up as a Detroit Lions fan. Upon

graduation, Mark intends to pursue a job in West Michigan.

Jeremy Kamp

Jeremy Kamp is from Orland Park, Illinois. He has many interests in the field, including hydrology, water

resources, site development, and construction management. When he isn’t hitting the books hard, Jeremy

enjoys playing baseball for Calvin College. Besides his interest in sports, Jeremy loves spending time in

the outdoors fishing and hunting. Since Jeremy has enjoyed his four years at Calvin so much, he plans to

pursue a job in West Michigan upon graduation in May 2015.

Nathan Laframboise

Nathan Laframboise is from Bolingbrook, Illinois. His areas of interest lie in water treatment processes

and water distribution. Ultimately, he wishes to see all people have access to clean, potable water in such

a way that does not over-burden the environment. After graduation Nathan would like to work as a city

civil engineer or for a county drain commission. In his free time Nathan enjoys studying theology, going

to family sporting events, and developing clever puns to the chagrin of his teammates.

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Julie Swierenga

Julie Swierenga is from Greensboro, North Carolina. Through research, studying abroad, and an

internship, she has had many opportunities to work with water resources, distribution, and treatment. The

intersection between civil engineering and geography is particularly interesting to Julie, including the way

that humans interact with space. Julie plans to pursue a job in water resources engineering upon

graduation.

Wendy Tabler

Wendy Tabler is from Milwaukee, Wisconsin. Her decision to move away for college has taken her much

farther than just Grand Rapids; with Calvin, Wendy has traveled to the Netherlands, to Kenya, to Peru,

and now to Ecuador. Wendy is passionate about international engineering, and is especially interested in

the connection between structures and water. After graduating from Calvin, Wendy plans to attend

graduate school to continue her education in structural engineering.

1.2 Project Background

1.2.1 Project Summary

Team 19, which has named itself the ACE (Agua y Cloración en Ecuador) Team, is designing a water

distribution system complete with chlorination dosing for the village of Apatug, Ecuador.

1.2.2 Location: Apatug, Ecuador

Apatug is a village of approximately 500 homes located in rural Ecuador, as shown in Figure 2 and Figure

3. The village’s current water source is a protected mountain spring shared with the surrounding

communities. A water distribution system is needed to provide clean water to each home. Because of its

location in the Andes Mountains, the difference in elevation between the source spring and the homes in

Apatug is significant. To maintain appropriate water pressures throughout the system, either the creation

of different pressure zones or the extensive use of pressure-reducing valves (PRVs) will be required.

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Figure 2. Location of Apatug, Ecuador, Indicated by the Red Placemark

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Figure 3. Terrain Map of Apatug, Ecuador

1.2.3 Current Water Situation

Apatug currently gets its water from a protected spring which is shared with four other communities,

serving a total of 1700 homes. A 110 millimeter diameter PVC feed line runs 7 kilometers from the

springs at 4360 meters elevation to deliver water to the communities, producing a total volumetric flow of

28 liters/second (L/s). [2] The spring protection and the feed line from the springs to the community were

completed in 2014, but the community currently has no water treatment or distribution network. [3]

In Apatug and in the case of most rural Ecuadorian villages, water is gathered from mountain springs and

piped to the village. This water is typically very clean, and can be drunk directly from the source without

treatment. While the water is clean, constant quality must be insured. This insurance takes the form of

spring protection. In order to keep animals out of the springs, the springs are covered with concrete or

steel structures which keep animals, both wild and domestic, and contaminated surface water from

tainting the spring water, as pictured in Figures 4 and 5.

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Spring protection structures must also protect the spring from water runoff due to large storms. For this

reason, Bruce Rydbeck states in a paper that “it is important that springs be excavated to a sufficient

depth so that the water is collected from the pervious gravel, sand, or fissured rock where water is flowing

before coming into contact with the topsoil.” By protecting springs, rural communities are provided with

a source of water which has constant quality, often mitigating the need for treatment and keeping

disinfection simple.

The community of Apatug has been visited by a global Christian health organization called MAP

International for over four years, receiving health and hygiene training. MAP has done a preliminary

study of water distribution changes, but it did not include a topographic study of the feed line and

required the uncommon construction of pressure breaking tank in mountainous areas. MAP asked Reach

Beyond (formerly HCJB Global) to do a water study of the community in 2011, and Reach Beyond

produced a design report including spring protection measures and construction of the feed line. [2]

The Ecuadorian government has recently required that all municipal water distribution systems include

chlorination for disinfection. There has been cultural and social resistance to chlorinating water because

the process has largely been unregulated, leading to sporadic dosing and taste issues. Part of the design

project will include a design for a chlorine dosing system that provides a consistent concentration of

chlorine in the distribution system, eliminating harmful pathogens while minimizing taste issues.

1.2.4 The Client

The project for the community of Apatug was proposed to the team by Bruce Rydbeck, PE, D. WRE., a

resident of Quito, Ecuador, and Rural Water Supply Consultant for Life Giving Water International. Mr.

Rydbeck has worked with many communities throughout Ecuador and Peru, coordinating with local

engineers and community members to perform spring protection, implement water distribution systems,

and investigate chlorine dosing in rural Ecuador. In June of 2014, team members Julie Swierenga and

Wendy Tabler traveled to Peru with a team of engineering students and professors to work with Mr.

Rydbeck to analyze and recommend changes to a rural water distribution system. This relationship led to

this senior design project.

1.2.5 The Project

The ACE Team will work in conjunction with Mr. Rydbeck and Ecuadorian engineer, Cesar Cortez, to

design a water distribution system for the community of Apatug. The system will be designed to utilize

locally available materials and installation methods, ensuring that pressures are well-regulated throughout

the village. In addition, a chlorine dosing system will be designed as part of the water system. The dosing

system will also focus on culturally appropriate technologies and locally-accessible materials and

chemicals to provide consistent disinfection throughout the water distribution network.

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2. PROJECT MANAGEMENT

2.1 Team Organization The ACE Team has assigned team roles to facilitate project management and implementation. However,

individual team members are responsible for research activities, as well as tracking hours. All of the team

members also contribute to report writing.

Wendy Tabler is responsible for scheduling and team management, ensuring that all tasks are completed

in a timely manner. She has also taken a supportive role in developing the computer model for the water

distribution system. Jeremy Kamp’s primary role is leading the computer model development for the

water distribution system. Jeremy is also responsible for contributing to the business plan and cost

estimation components of the project. Mark De Haan is in charge of the budget for the team. He is also

responsible for the completion of the business plan and contributing to chlorine bench study development.

Nathan Laframboise is responsible for organizing the research efforts of the team. He has taken a lead in

communicating with pump suppliers for bench study materials and contributing to chlorine bench study

development. Julie Swierenga is in charge of the website for the team, as well as email communications

with the client, Bruce Rydbeck. She is also responsible for chlorine dosing calculations and design

considerations.

2.2 Schedule The two semesters of the senior design course have been split into two main focuses for the ACE Team.

The first semester will be spent mainly on designing the water distribution system while also looking at

the feasibility of the project. The second semester will focus on the design of the chlorination system and

the method through which the chlorine will be administered to the distribution system. In January, four

members of the ACE Team will travel to Ecuador to visit the community, perform water chemical

analysis and quality testing in Apatug, and visit similar distribution systems that are currently in

operation. The complete schedule is outlined in a Gantt chart, which is included in Appendix A.

On a weekly basis, the ACE Team gathers to share research and modeling results and also has a meeting

with their project advisor each Monday at 1:30 pm to discuss progress and address questions. After this

meeting, the team decides on a plan of action for the next week and tasks each member should

accomplish. Each team member tracks hours spent on the project using a spreadsheet located on a shared

Google Drive. Since the project has two major components: the water distribution system and the chlorine

dosing system, team members meet in smaller groups more frequently throughout the week.

2.3 Budget The ACE Team has been provided with a budget of around $500. This majority of this money will go

toward the bench scale study, purchasing a flow injector pump to administer chlorine to a stream of water

which varies in flow. This pump will cost approximately $300. Four members of the ACE Team also plan

on traveling to Ecuador at the end of January to connect with members of the community and to receive

input regarding the best locations in the village for reservoirs and piping. Between flights, living

accommodations, and a water testing kit necessary to collect water quality data, the trip has been

estimated to cost $5319 in total. Mark De Haan has been placed in charge of ACE Team’s budget.

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When making design decisions about materials and methods to use in the distribution and chlorination

system in Apatug, the ACE Team does not simply consider options of lowest cost to make design

decisions. Cultural appropriateness is a key aspect of selecting construction and chlorination materials. In

addition, the community of Apatug will likely seek government assistance for assuaging the costs of the

recommended distribution system. The ACE Team will use the provided senior design for bench study

materials and water testing material necessary for chlorine dosing design, but trip funding will be funded

by team members, and the distribution system itself will be funded by the community and Ecuadorian

government.

2.4 Method of Approach The ACE Team has approached this senior design project with humility, gratitude, and awareness of the

profound effect that the project may have on the people of the Apatug community.

First, the team is aware that the assistance of more experienced and knowledgeable mentors is essential to

the success of the project. The team has used the resources of professors, an industrial consultant, and the

project client to ask questions and seek information. A humble posture allows the team to be open to

suggestions and new alternatives that have not yet been considered. Humility puts the team in a position

of learning, facilitating communication between team members and mentors, and also creating an

incentive for continued research and learning throughout the project.

Secondly, the team is grateful for the opportunity to partner with Bruce Rydbeck and the community of

Apatug to utilize time and resources to design a distribution and chlorination system for the community.

The team has been blessed with access to higher education, engineering software, technical knowledge,

and a supportive learning environment, which are all resources that can be used to benefit the people of

Apatug. The team is also grateful for the opportunity to be hosted by the community in January.

Finally, the ACE Team is aware of the gravity of delivering clean water to a community, which provides

inspiration and incentive for work on all aspects of the project. All professional engineers design and

implement projects that have an effect on human health or well-being, and this project has the potential to

provide clean water to the residents of Apatug for years to come. This knowledge reinforces the

importance of design norms in the implementation of the project, particularly those of justice, cultural

appropriateness, and sustainability.

This project is being approached with a methodology of research, model development, testing, and

redesign. After initial research was performed, a computer model was developed to model the distribution

system. This model will be tested using EPANET software and will also be informed by communication

with the community of Apatug before a final recommendation is made. Similarly, the chlorination system

has a foundation of research, and a bench scale study is planned to test the effectiveness of the chosen

system. It is important that each aspect of the design be tested and evaluated before a final design is

recommended.

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3. PROJECT OVERVIEW

3.1 Purpose and Objectives

3.1.1 Distribution

The purpose of designing a water disinfection and distribution system for Apatug, Ecuador, is to supply

its 500 households with clean water under manageable pressures. Currently, small reservoirs scattered

throughout the village are shared by animals and villagers. By providing a metered tap connection in

most homes, the villagers will no longer have to walk to get water that has been contaminated by animals.

In November 2002, the United Nations Committee on Economic, Social and Cultural Rights adopted

General Comment No. 15, which declares that “the human right to water is indispensable for leading a

life in human dignity [and] is a prerequisite for the realization of other human rights.” [4] This right is

further defined as “entitling everyone to sufficient, safe, acceptable, physically accessible and affordable

water for personal and domestic uses.” [4] In July 2010, the United Nations (UN) General Assembly

explicitly recognized this right through Resolution 64/292. [5] The UN Millennium Development Goals

call for cutting the “proportion of the population without sustainable access to safe drinking water and

basic sanitation” in half by 2015. [6] This distribution system works toward this Development Goal and

will provide the villagers of Apatug to their human right of sustainable access to clean drinking water.

In designing the system, the ACE Team was given certain objectives by the client, Bruce Rydbeck. [3]

The reservoirs should be designed to hold 35% to 40% of the average daily demand for a given pressure

zone or zone of service. Static pressure at each home should be in the range of 20 to 60 meters, or if need

be 10 to 70 meters, which would be admissible because Apatug is a mountainous community. Servicing

as many houses as possible with a private tap is a main objective. In the cases where a home connection

is not feasible, a community faucet will be constructed nearby. The main objective for the distribution

system is to provide a full design report that can be submitted to community leaders, allowing Apatug to

begin construction of the reservoirs and pipelines for the distribution system.

3.1.2 Chlorination

The purpose of chlorination is to kill pathogens that can grow on the inside of pipes, walls of storage

tanks, and water mains. Disinfection renders the water safe for human consumption. Currently, water is

collected from a protected spring on Mt. Carihuairazo and transported to the city of Apatug, Ecuador, via

a seven kilometer PVC water main. Although the spring water is of acceptable quality due to natural

filtration, there is still ample opportunity for organisms to grow within the distribution system.

Additionally, in 2008, Ecuador passed legislation making it mandatory that all cities have chlorine

residual in their systems to ensure against pathogen growth. [7] Apatug is a large enough community that

a chlorine residual in the water system is necessary if any further development funding by the Ecuadorian

government is to be supplied.

The disinfection objective of this project is to administer chlorine to the distribution system according to

Ecuadorian regulations. Further specifications have been set forward by our client Bruce Rydbeck. [8]

Chlorine should be introduced into the system using liquid injection pumps. These pumps should be

adjustable so they increase their chlorine output during times of high demand and dial back during times

of low demand. The range of flow rates the pumps will be expected to operate at vary between 1 to 6 L/s,

and the pumps should dose to range of 0.5 to 2 parts per million (ppm). It is ideal to use chlorine that can

12

be acquiesced within Ecuador. Given the low flow rates at certain nodes it is critical that a chlorine

residual be maintained to prevent pathogenic growth.

3.2 Design Constraints There are a number of aspects of the design process that will constrain how the final product is developed.

The first constraint is the disinfection regulations which have been set by the Ecuadorian government that

state that chlorine must be used for disinfection. While chlorine is normally used as the primary

disinfectant in the majority of water systems, this regulation prevents the use of more complex

disinfection methods such as ozone or ultraviolet, which do not leave a residual disinfectant in the

distribution system.

Material availability in Ecuador also limits the design of the Apatug distribution system. To design a

system which is culturally appropriate, materials such as ductile iron are quickly ruled out of the design

process due to their lack of availability. Additionally, in order to be culturally appropriate, material cost

must be considered. Instead of designing the system as a looping network, which would provide constant

water supply even during pipe replacement, designing the system as a branching network requires much

less material and makes finding leaks significantly easier; therefore, it is a more desirable design strategy.

Another important constraint in designing the distribution system is the change in elevation. These

elevation differences require the placement of reservoirs setting a pressure zone or PRVs to keep

pressures from being too high in various parts of the village. This large elevation range constrains how

much of the village can be regulated by a single pressure district and dictates the number of pressure

districts that are necessary. The village consists of 500 homes, and all of these homes must be served by

the 5 L/s flowing from the spring while maintaining adequate pressures.

Along with the establishment of pressure districts, the design specifications of the system are based on per

capita daily consumption of water and the number of residents within a given pressure district. Water

demand constraints will not only play a role in the sizing of the pipes but also in the sizing of the

reservoirs.

All of these factors must be taken into careful consideration when designing the distribution system.

Inability or unwillingness to do so could result in a faulty product or system which finds itself in

disrepair.

3.3 Design Criteria In order to design a chlorine dosing system, design decision must be made that fulfill the goal of the

project while considering the design norms of cultural appropriateness, justice, and sustainability. These

design criteria are also informed by the characteristics of different chlorination methods. Decision

matrices were developed and used to determine the most appropriate disinfection material and delivery

method for the community of Apatug.

3.3.1 Disinfection Method

The following criteria are considered in determining the disinfection methods and are used to weigh

alternatives as shown in a Decision Matrix found in Appendix B:

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1. Chemical Source – Does the chemical arrive ready to use or does it need further refining before it

can be dosed?

2. Contact Time – How much time is needed to get the desired kill of organisms? This number is

based upon ideal conditions of pH = 8, 75oF water with no turbidity or NOM.

3. Typical Application Dose – How much disinfectant needs to be added per liter of water (mg/L)?

4. Safety – How hazardous is the chemical to humans and does anyone handling the chemical need

to wear special clothing to mitigate exposure?

5. Ease of Use – Can the disinfectant be used as both a primary and secondary disinfectant?

6. By-Products – If the disinfectant does come into contact with natural organic matter (NOM), are

disinfection by-products (DBPs) at threat of formation in the system?

7. Legality – Will the disinfectant leave a chlorine residual in the system in accordance with

Ecuadorian regulation?

3.3.2 Disinfection Dosing

The following criteria are considered in determining the disinfection dosing methods and are used to

weigh alternatives as shown in a second Decision Matrix found in Appendix B:

1. Liquid Inject – Can the chlorinator handle liquid sodium hypochlorite?

2. Adjustable Feed Rate – Is the feed rate self-regulating?

3. Dependability – Is the method rugged enough for prolonged use without maintenance?

4. Ease of Construction – Are special expertise needed to set the system up properly?

3.4 Design Norms Design norms provide a framework through which the project will be completed. These design norms

ensure that the project is done with the correct mindset and that the ethical guidelines, which are an

important aspect of the engineering profession, are considered in the areas of technical design and ethical

constraints.

3.4.1 Cultural Appropriateness

When working on a project in a foreign country, designing with cultural appropriateness in mind is

paramount. In a village that has never had a water distribution system with disinfection, it is important

that the community embraces the project so the system does not fall into disrepair or cease to provide the

required disinfection. For these reasons, designing the system to be cost effective and easy to build by

local labor is important, while implementing a design using materials that are readily available is equally

important in the situation that maintenance or repair is necessary. Additionally, the chlorination must be

carefully regulated so that it has a minimum effect on taste. Cultural appropriateness also takes into

account non-technical aspects of the design. The potential tank locations may be limited by current

conceptions of different places in the Apatug area, desired spigot locations may be defined by current

practices, and network connections may need to be defined by cultural relationships. In order for the

system to be embraced, it must work in conjunction with the culture of Apatug.

3.4.2 Transparency

In order to design a system which will work correctly and be reliable for years to come, transparency is

important for all aspects of the design process. The team has to be upfront with the client, advisor, and

industrial consultant so that any problems the team may face will be solved correctly and efficiently. Any

14

questions should be communicated clearly to ensure understanding between team and consultant. Any

potential cultural issues must be addressed with the community. While learning is an important aspect of

the senior design course, the team is asked to produce a final product, which should be designed to be

efficient and reliable. For this reason, communication between the team and its consultants must be

transparent, so all aspects of the project are correctly addressed.

3.4.3 Justice

The right to clean, drinkable water often requires hard work on the part of those living in developing

countries like Ecuador. For this reason, justice is the final design norm around which the team will focus

the project. The design and implementation of a water distribution system complete with disinfection

allows the people of the village of Apatug to have access to an ample supply of clean water. Through that

access, the team seeks to bring justice to those who are so often stuck on the margins of society.

3.5 Design Alternatives

3.5.1 Distribution Pressure Control

In order to keep pressures at the household connections between 20 and 60 meters (or 10 to 70, if

necessary), two alternatives are possible. Firstly, PRVs could be used at each residence to lower the high

pressures caused by the significant elevation difference to manageable target pressures. Although these

would be simple to install with the new system, they do not lower pressures within the pipes themselves

and more valves would be required with the addition of new houses and future population growth.

According to a survey performed by Cesar Cortez, the lowest reservoir on the pipeline before reaching the

town is at an elevation of about 3490 meters, which is about 200 meters above the lowest elevation

household in Apatug. This elevation drop would cause very high pressures within the pipes and put the

system at risk of collapsing. Alternatively, pressure head zones could be created by constructing

reservoirs at different elevations throughout the distribution system. Reservoirs provide stability to the

entire system, protecting both the homes and pipes from excessive high pressures and breaking the

pressure of the incoming water. Reservoirs also equalize flow, allowing the system to better deliver peak

flows, and they provide storage for an emergency water supply. Although reservoirs are more costly to

install, the client, Bruce Rydbeck, has requested the use of reservoirs because Apatug is a compact

community and the reservoirs provide significant long term advantages. [9]

3.5.2 Distribution Pressure Zones

The hydraulic pressure in a system is governed by the equation:

𝐻 = 𝑧 +𝑃

𝛾 , (Equation 1)

where 𝐻 is the piezometric head, 𝑧 is the elevation, 𝑃 is the pressure, and 𝛾 is the unit weight of water.

With pressures given in units of head (such as meters), this equation simplifies to

𝐻 = 𝑧 + 𝑃. (Equation 2)

As illustrated by Figure 6, the piezometric head is set by the elevation of the water level in the tank

connected to that branch of the system. The head levels needed in the system can be set by the desired

range of experienced pressures at the elevations of the houses. Because the pressure is greatest where

elevation difference is greatest, the highest pressure in the range can be determined by using the elevation

15

for the lowest house in Apatug. This assumption sets the head in the first pressure zone. From there, the

highest elevation of a house that can be served within the acceptable range of pressures for this calculated

head can be determined. One meter was added to this value to determine the lowest possible elevation for

the second pressure zone. This process was repeated until all houses were contained within a pressure

zone. Calculations can be found in Appendix C.

Figure 6. Piezometric Head Diagram in a Hydraulic System (sketch by Julie Swierenga).

Following these calculations, Apatug’s distribution system could be designed as a four pressure zone

system, requiring 18 PRVs for the outlying households, or as a five pressure zone system with room for

growth. The five pressure zone system can be seen in Figure 7. Because the use of PRVs was discouraged

by our client and the client suggested using either four or five zones to provide for future growth, the

recommended design will use five zones established by five reservoirs.

16

Figure 7. Five Pressure Zone System

17

3.5.3 Distribution Design Approach

Rural water distribution system pipe sizes are normally based on Church’s method, which identifies the

size of pipe needed by the area and number of connections that pipe serves in a table, as given in Table 1.

Table 1. Church's Method typically used for design of rural water systems in Ecuador [10]

PVC Pipe

Diameter

Interior Pipe

Diameter [mm] Area [mm2]

Number of Maximum

Connections

25 22.4 394.08 3

32 29.0 660.52 10

40 36.2 1029.22 20

50 45.2 1604.60 32

63 57.0 2551.76 50

75 69.2 3761.00 100

90 81.4 5204.03 125

The use of such a table allows field staff to make adjustments in the field as they see fit. This works

especially well, given that distribution systems are typically designed as branching systems for ease of

finding leaks and piping cost reduction. However, because Apatug is a compact area, it may lend itself to

some interconnected pipes. Loop-type systems are most easily analyzed with computer software.

Computer software also offers a lot of flexibility to test different possible scenarios and see the effect of a

small change to the entire system. Additionally, a commonly used program in industry called EPANET is

free for download from the Environmental Protection Agency (EPA). Field staff, as well as engineers like

Bruce Rydbeck and Cesar Cortez, could continue the use of this computer model without incurring

software charges. For its flexibility and graphical ability, the design will employ a computer model to test

the proposed distribution network. This will be checked with Church’s method to ensure results are

similar in order that field staff and local engineers will trust the design.

3.5.4 Form of Chlorine Disinfection

Disinfection of drinking water can be achieved through several different chemical processes, including

ultraviolet radiation (UV), oxidation, and chlorination. Because chlorine is the only one of these

disinfection processes that leaves a residual concentration in the distribution system after initial

chlorination, the Ecuadorian government requires the use of chlorine for disinfection.

There are several different chemical forms of chlorine that were evaluated by the team through initial

research and consideration of design considerations including cultural appropriateness, safety, and

humility. The alternatives considered were solid and liquid hypochlorite, chlorine dioxide, gaseous

chlorine, and chloramines. Chloramines were ruled out because of their limitation as a poor primary

disinfectant, and chlorine dioxide utilizes oxidation to disinfect rather than free chlorine. Gaseous

chlorine is the most efficient method for chlorine disinfection, but it is also the most difficult to transport

and store, and it is a deadly toxin requiring careful handling and management. A decision matrix was used

to select liquid sodium hypochlorite as the preferred method of disinfection due to its wide availability

and ease of storage and delivery. These chlorine alternatives are further investigated in the initial research

section of the report.

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3.5.5 Chlorine Dosing System

After selecting liquid sodium hypochlorite as the disinfection method for Apatug, a dosing method for the

chlorination system must be selected. The main goal of the chlorine dosing system is to provide a

constant chlorine residual concentration that responds to daily fluctuations in water demand in the

community. Since chlorine has been largely unregulated in Ecuador, there is a mistrust of chlorination

disinfection due to taste issues that occur with inconsistent or overdosing. Therefore, the team

investigated several different types of dosing systems in an effort to maintain constant residual

concentrations that respond to demand variation, including timer-driven pumps, volumetric flow meters,

and nonelectric fluid-driven pumps.

Timer-driven pumps do not respond immediately to unexpected changes in flow, relying on consistent

demand patterns to maintain a constant residual chlorine concentration. Volumetric flow meters

connected to a dosing pump would allow for instant dosing response; however, flow meters require

electronic communication between the meter and the pump, increasing the complexity and potential for

failure of the dosing system. To best align with the design norms of cultural appropriateness and justice,

the team plans to implement a bench scale study to test the effectiveness of different brands of nonelectric

fluid-driven pumps, which deliver a chemical dose proportional to the flow of untreated water. These

nonelectric injector pumps are beneficial in that they are unaffected by occasional power outages, and

they minimize taste and odor issues associated with unregulated chlorination.

19

4. INITIAL RESEARCH

4.1 Distribution System Although rural communities in Ecuador are experiencing growth in their access to an improved water

source, it is still inadequate and in need of improvement. As seen in Figure 8, about 25% of rural Ecuador

still does not have access to an improved source. Although the gap between the rural water access in the

United States and Ecuador is closing, improvements in the area of water distribution and utility

infrastructure in villages such as Apatug are still needed.

Figure 8. Percent of rural population with access to improved water source in Ecuador, United States [11]

4.1.1 Importance of Community Ownership

The United States National Research Council found that “without adequate management and revenues,

small communities will be unable to maintain even low-cost technologies.” [12] If the community is not

involved with the design and implementation of the distribution system and does not take ownership of

the system, it is doomed to fail. Even if the team could design a system to address every necessity of the

village, if the community does not hold stakes in the system, any minor maintenance issue could cause the

collapse of the whole system. CEO Edward Breslin of Water For People notes that “approximately 50,000

rural water points are broken and US$215-360 million of investment wasted because of poor

programming and careless implementation.” [13] In order to facilitate this connection with the

community, the team’s travel to Ecuador will be key. There the team will be able to meet with community

leaders to determine where reservoirs can and should be located in order to finalize the distribution

network design.

In his article addressing water and sanitation strategy for developing countries, Daniel Okun, a professor

at the University of North Carolina, found that the second biggest problem facing water systems in the

0

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20

developing world is insufficient water management, only second to the issue of inadequate systems that

cannot handle urban growth or apply inappropriate technology. [14] At the “Cusco+ 10” International

Seminar in 2010, this problem was still identified as one of the five challenges facing rural water

distribution systems in the next decade. [15] If a community is supplied with a solar panel to power an

aspect of the water system, but no one has training on how to protect or fix the technology, a broken

system means not only that the community’s system cannot be used but also that they have already been

“checked off” a list of villages needing technology assistance. The U.S. Agency for International

Development’s Water and Sanitation for Health project found at its 10-year evaluation that “local

institution-building is the key to transferring sustainable skills.” [14]

Rather than starting from scratch, Okun suggests assessing existing institutions and being “open to and

aware of other models that have been successful and may be appropriate.” [14] Additionally, because

traditions of free water make funding of management or of water projects difficult, the public must be

informed and educated as to the importance of well-managed and maintained clean water for both health

and convenience. [14]

4.1.2 Typical Costs by Usage

In the 1998 Annual Review of Energy and the Environment Journal,

“heavily subsidized services [are found to] lead to relatively slow service expansion, poor

quality service (owing to cost- and performance-unaccountability to those being served),

and inefficient resource use: the subsidized services are provided to the lucky ones who

happen to be also otherwise privileged, while the unlucky ones, who happen to also be

[16] poor, pay a huge human, social, and financial price to get the service.” [17]

Furthermore, the Review notes that there is “a significant body of research demonstrat[ing] that many

rural people can and will pay for improved water supplies”. [17] Some even suggest that because of these

factors and general financial issues in developing countries, capital costs should be minimized, even if at

the expense of more maintenance later. [14] This perspective is another strategy for community

involvement. Water For People has found that co-funded projects “are far more sustainable” than ones

paid for by outside sources that have the communities pay by providing the labor to create the system and

that in co-financed projects, the “communities rightly call these projects “theirs”, demonstrating that

elusive sense of ownership that will never be obtained by ‘sweat equity’ alone.” [13] People care about

what they pay for; thus, charging for water usage will make communities more aware of their water usage

and will force water management to be accountable for efficient and quality water services. According to

Mohan Munasinghe, “recent evidence shows that price is an effective long-run technique of demand

management”. [16] This cost must be fair and conscious both of what consumers can pay and of the

system costs associated with providing the service. Munasinghe recommends three general principles of

fairness and equity, including “fair allocation of costs among consumers according to the burdens they

impose,… price stability over time, and provision of a minimum level of service to persons who may not

be able to afford the full cost”. [16] This cost cannot be too great to deny the basic right to clean water

each person deserves. Part of the considerations of fairness may also include fluctuations of cost based on

certain factors such as time of day, season, and consumer category (i.e. for a home business or crop

farmer or simple domestic household). However, time of day sensitive meters are significantly more

expensive; thus, Munasinghe suggests that “the use of time-of-use metering devices would not be

21

economically justified for residential users in low-income countries”. [16] A per month basis for

consumption, however, remains a viable option. Typical values for marginal costs of water supply can be

found in Table 2.

Table 2. Typical values for marginal costs of water supply [16]

Country Project Marginal Cost

US$/m3

Brazil Sao Paulo State

Water Sector Project 0.35

Haiti Port-Au-Prince

Water Supply Project 0.30

Philippines Metropolitan Manila

Water Distribution Project 0.35

Nigeria Lagos Water Supply 0.23

Democratic Republic

of Yemen

Al Mukalla Water

Supply Project 0.69

USA New York State

Water Supply

Winter: 1.21

Summer: 2.73

Australia Perth Water Supply Winter: 0.096

Summer: 0.176

According to a study by the World Bank, there are nine factors that determine a community’s willingness

to pay for improved water sources: [18]

1. Perceived Benefits – If the water tastes, smells, or does not follow tradition, people will not pay

as much for it, even if it might be cleaner than the water from the existing system.

2. Income – People will use more water if they have more disposable income. For example, “in

Chile, for every 10 percent increase in income, families consume 4 percent more water per

capita”. [18]

3. Water Charges – A lower price will encourage more demand.

4. Other Prices – If electricity is less important than water to the community, users will not be

willing to pay more for water than they do for the more necessary electricity.

5. Value of Women’s Time – In countries where women’s time is not valued, male community

leaders are less likely to pay for water since the females do not need free time they would not use

productively. When women play a more significant (especially economically significant) role, the

community is more willing to pay to free their time.

6. Level of Service – People will pay more if the source is connected directly to their own house.

7. Characteristics of the Existing Source – If the existing source is decent and inexpensive, people

will not be motivated enough to improve the source to make it better.

8. Other Productive Activities – If improved access to water makes other activities more productive,

people will pay more for it.

9. Credibility of External Agency – When the community trusts the managing agency, they trust

their money is being put to good use and is actually necessary.

22

Considering each of these nine factors will ensure that even in the costing of the water system, the

community can play a role in the creation of this system and will retain more ownership of this system.

4.1.3 Standard Design Values

According to a study of intermittent and continuous modes of water supply, Andey and Kelkar suggest a

peak hour factor of between 2.0 and 3.0. [19] For a community the size of Apatug (about 2500

inhabitants), the EPA records that the average maximum day ratio is 2.28 and the median ratio is 2.00 for

a publicly owned system. [20] In addition, the average day demand should account for leakages that are

likely to be present in the system. In a study of water pricing in developing countries, Munasinghe notes

that they assumed unaccounted-for-water would decrease from about 30 to 24% over six years; however,

“in reality, the starting value of average losses was 34%, and remained at this level thereafter”. [16]

Significant variance exists in standard design values for average daily water needs per capita. Bruce

Rydbeck typically uses 120 L/person/day. Based on World Bank information of annual freshwater

withdrawls and the percentage of that which is domestic from 2013 leads to a typical use of 231.6

L/person/day. [11] Differing still, 2007-2008 Calvin College Senior Design Team Equatic Ecuador took

flow rate measurements to find that in Cajabamba, the average daily usage per capita was at least 160 L.

[21]

4.1.4 Household Connections

Household connections are made complete with a check valve, shut-off valve, and water meter if the

home has existing interior plumbing. If the homes do not have existing interior plumbing, an elevated

spigot can be made readily available near the home. The elevated spigot is constructed from a 6-inch

concrete pedestal that is between 70 and 90 centimeters in height. [2] At the top of the pedestal is a 90°

bend that has a water meter and a spigot on the end. Figure 9 shows a typical spigot.

23

Figure 9. Picture of a Typical Spigot [2]

4.2 Disinfection According to the World Health Organization (WHO), “infectious disease caused by pathogenic bacteria,

viruses and protozoa or by parasites are the most common and widespread health risk associated with

drinking water” [17], and therefore "disinfection is unquestionably the most important step in the

treatment of water for public supply.” [22] Drinking water disinfection is most typically performed

through the use of chlorine-based chemicals, but other methods utilizing Ultraviolet light (UV) and other

oxidizing agents such as ozone are also used to eliminate pathogens in drinking water.

Chlorination is commonly used as a disinfection technique, because the presence of free chlorine in water

for sufficient time inactivates up to 99.99% of enteric bacteria and viruses. Doses of free chlorine are

typically a few milligrams per liter (mg/L) with a contact time (CT) of approximately 30 minutes (min).

[22]. The dosing of free chlorine is dependent on the quality and chemistry of the source water, including

temperature, pH, turbidity, and the concentrations of ammonia, hydrogen sulfide, iron, manganese and

other ions. [17] For example, a free chlorine dose of 2 mg/L and 30 min CT provides 99.9% disinfection

of Giardia at 20 degrees Celsius, 1 NTU (Nephelometric Turbidity Unit), and pH of 7. [17] A major

24

benefit of chlorine disinfection is that it leaves residual chlorine that continues to disinfect the drinking

water while it is in the distribution system. According to a 1998 article in the Annual Review of Energy

and the Environment, residual free chlorine of 0.25 mg/L is considered adequate for warm climates for a

total organic carbon (TOC) concentration of less than 0.25 mg/L. [17] Residual disinfection is especially

important in water distribution systems that are prone to contamination and improperly sealed, such as

systems in rural or developing communities. [23]

One concern with chlorine disinfection is the production of DBPs, which result when free chlorine reacts

with NOM in the source water. [23] Some DBPs are known carcinogens, and at high concentrations they

can result in taste and odor issues in the chlorinated drinking water. Since DBP production is associated

with NOM and high turbidity, chlorination is more effective with source water that is protected from

contaminants and has lower turbidity. In the case of the springs that serve Apatug, spring protection

methods have been utilized to reduce NOM concentrations and protect source water quality, reducing the

concerns associated with DBP production. [3]

4.2.1 Republic of Ecuador Disinfection Policy

According to the drinking requirements section of the 2010 Ecuadorian Technical Standards document

released by the Ecuadorian Standardization Institute, disinfection is required in all water distribution

systems. Specifically, free chlorine is the required method of disinfection because it provides a residual

concentration in the distribution system. The Ecuadorian Technical Standards discusses the use of

gaseous and liquid chlorine, including electrolysis. [24]

Because the government of Ecuador requires that chlorination be used as the primary disinfectant in water

distribution systems, disinfection alternatives such as ozone and ultraviolet treatment which do not

maintain a residual disinfectant in the distribution system were not considered as options for Apatug.

Point-of-use chlorination was also excluded from consideration, because an integrated chlorine treatment

within the water distribution system improves the likelihood that the Ecuadorian government will provide

funding for the distribution system in Apatug. Point-of-use chlorination has also been shown to be less

effective than disinfection techniques that are applied to the entire water system. [25]

4.2.2 Chlorine Alternatives

There are several different forms of chlorine that have been proven effective in drinking water

disinfection, including solid calcium hypochlorite, liquid sodium hypochlorite, and gaseous chlorine.

Other alternatives include chlorine dioxide and chloramines, both of which have been associated with the

production of fewer DBPs that can be carcinogenic at high concentrations. [26], [27] The type of chlorine

used for disinfection varies in ease of production, ease of use, ease of storage, required contact time,

DBPs produced, and available residual chlorine.

Sodium Hypochlorite (Liquid)

Sodium Hypochlorite (NaOCl) is a liquid solution that is diluted and mixed with untreated water for

disinfection. It is relatively simple, low cost, and easy to transport. Storing liquid chlorine is less

dangerous and easier to use than gaseous chlorine; however, the solution is corrosive, so it is best stored

in plastic drums. [28] Liquid sodium hypochlorite, or bleach, provides a residual free chlorine

concentration in the distribution system. Sodium hypochlorite is known to produce DBPs, especially in

source waters that are high in NOM.

25

Liquid sodium hypochlorite is often used in developing and rural regions because of its wide availability

and relative ease of storage. In an American Water Works Association (AWWA) article about safe

drinking water in Guatemala, concentrated sodium hypochlorite is cited as being used in the Center for

Disease Control and Prevention’s Safe Water Method to reduce bacterial disease. This Safe Water

Method has been successfully implemented in communities in Bolivia, Peru, Nicaragua, and Ecuador.

[22]

Electrolysis

Sodium hypochlorite can be purchased and stored in liquid form, but it can also be produced

through the electrolysis of sodium chloride (NaCl). [22] In electrolysis, household salt is

electrolyzed without separation of the anode and the cathode to form chlorine gas and a brine

solution, which react to form a low concentration NaOCl solution. Electrolysis of chlorine is

typically performed with a permeable membrane to limit chlorine ion movement between the

anode and the cathode, as illustrated in Figure 10. An electrolysis process is currently utilized in

the community of Yanacocha, which is near Apatug. This NaOCl solution can be directly added

to the source water as a disinfectant. The benefits of electrolysis are that it is easier and less

expensive to store NaCl than large amounts of liquid hypochlorite, and the community has greater

control over the supply chain of the source chloride. Once the hypochlorite brine is made through

electrolysis, the solution still must be properly dosed. [17] According to Bruce Rydbeck, the

government sponsors chlorine production through electrolysis in some areas of Ecuador, trading

NaCl for liquid chlorine solution. [29]

Figure 10. Schematic of Chlorine Electrolysis to Produce Chlorine Gas. [30]

Calcium Hypochlorite (Solid)

Solid calcium hypochlorite (Ca(OCl)2) typically is in the form of powders or tablets that are easily

dissolved in water. This solid hypochlorite can be stored in bulk and remains effective for up to a year.

While Ca(OCl)2 is relatively simple, low cost, and easy to transport, it can be corrosive and explosive

when in contact with organic materials, affecting storage requirements. [28]

Chlorine Dioxide

Chlorine dioxide (ClO2) is a disinfection alternative that has been shown to reduce the formation of DBPs

during primary disinfection, [26] however it disinfects by oxidation rather than chlorination. [31] While

26

ClO2 is very effective against bacteria and viruses, it is difficult to manufacture and monitor, limiting its

use in small-scale and rural systems. [28] Dilute aqueous solutions are stable if kept well-sealed and

protected from sunlight, but the concentrated vapor is potentially explosive. In addition, ClO2 must be

manufactured at the point-of-use, requiring skilled technicians and careful monitoring. [26]

Gaseous Chlorine

Gaseous chlorine (Cl2) is a cost-effective chlorine disinfection alternative, but it is difficult to both

transport and store. Since Cl2 is a deadly toxin in its gaseous form, it must be carefully regulated and

dissolved in water under vacuum. Cylindrical containers are typically used to store compressed Cl2 in

liquid form. [26]

Chloramines

Chloramines are a mixture of chlorine and ammonia that are often used in water disinfection because of

the reduced risk associated with harmful DBPs. Chloramines are more stable than free chlorine and result

in less taste and odor issues that are associated with DBPs. [27] Although chloramines have a lower

health risk in terms of DBP production and are relatively inexpensive, chloramines are typically only used

as a secondary disinfectant due to their high required contact time. [26] The creation of chloramines also

requires skilled operation and significant infrastructure for mixing. [28]

4.2.3 Dosing Alternatives

In addition to the wide variety of types of chlorine administered for disinfection, there are a number of

chlorine dosing methods that can be used in small-scale water distribution systems.

Volumetric Flow Pump

Pumps are typically required for dosing of liquid chlorine solutions, and it is important that they respond

to varying flows to maintain a relatively constant chlorine concentration in the distribution system.

With Flow Meter

Flow meters can be used to measure the volume of untreated water coming from the source spring

into the water disinfection system. It is relatively simple to install a flow meter in a water

distribution system, but communication between the flow meter and the dosing pump requires

electronic signals, increasing the complexity of the system.

Nonelectric Fluid-Driven Injectors

Nonelectric fluid-driven injector pumps are dosing pumps that do not require electricity and

provide a liquid chemical feed that is proportional to flow, allowing for a relatively constant free

chlorine concentration in the treated water. [32] This type of pump does not require a full-time

operator, but it does require occasional maintenance and O-ring replacement. There are several

different suppliers of fluid-driven injector pumps, including HyroSystems’ Dosmatic® pumps

and Tefen’s MixRite pumps.

The team has been in communication with HydroSystems, which has given a cost estimate of

$300 for a MiniDos injector pump. MixRite has a similar injector in their 3.5 series, but the team

has yet to receive a cost estimate from Tefen. The pump specifications for both the Dosmatic®

MiniDos and the MixRite 3.5 are included in Appendix D.

27

Timer Controlled Pump

Timer controlled pumps that are programmed to dose chlorine at times of peak flow are a simple dosing

method for liquid chlorine. This method was used with some success in a rural water distribution system

disinfection pilot study in Ecuador. [33] However, timer controlled pumps do not respond well to periods

of unusually high or low demand, which can result in inadequate disinfection or excess residual chlorine.

It is important to have well-regulated and consistent chlorine dosing for effective disinfection and also to

prevent taste and odor issues.

4.3 Available Materials Ecuador typically uses PVC pipe for water distribution systems due to cost and ease of connection. It is

also lightweight which allows most of the pipe to be moved by hand with no need of heavy machinery for

placement. The pipe must be buried in trenches at least 1.2 meters deep, mainly for its protection. Pipes

used are usually selected as the thickest available, which is still not as thick as typical pipes in the United

States. [2]

Bruce Rydbeck has specified the use of Plastigama Pipes as a common pipe supplier in Ecuador. The

nominal pipe diameters from their catalog range from 20 mm to 630 mm. Within this range of diameters

the pipes can withstand maximum pressures up to 1,250 kilopascals (kPa) with their greatest wall

thickness. Any size pipe can withstand at least 500 kPa. [34]

Some of the common accessories and unions used with this PVC pipe are 90°, 45°, 22.5°, and 11.25°

bends. There are also four way junctions, and T junctions. Two different ways to join PVC pipe are by

elastomeric sealing and solvent cemented joints. According to Bruce Rydbeck, bell and spigot solvent

welded joints are most commonly used. [2]

4.4 Water Reservoir Design The Great Lakes Upper Mississippi River Board (also known as the Ten States Standards) identifies the

goal of designing a water storage structure as to “provide stability and durability as well as protect the

quality of the stored water.” [35] In order to provide stability, the water storage structures must have

adequate capacity to equalize the flow rates between normal daily fluctuations. Additional capacity may

be required to provide water for emergencies, such as fires or equipment failures. AWWA suggests that

half of the storage volume is designated for equalization storage at about 20-25 percent of the average

daily demand. [36] For Ecuador, Bruce Rydbeck suggests that reservoirs are typically sized at 35-40

percent of the average day demand. [37] Assuming half of that volume is for equalization storage, per

AWWA standards, both the US standard and the Ecuadorian typical value can be satisfied by taking the

storage structure volume to be 40 percent of the average daily demand for the area that it serves.

In the Water Distribution Systems Handbook, Walski states that “because water-quality problems are

usually worse in tanks with little turnover, no longer is it safe to assume that a bigger tank is a better

tank.” [38] Thus, the design solution must not be overdesigned, and subsequent monitoring of the tanks

must occur. Some aesthetic indicators might include poor taste and odor, sediment accumulation, and

water temperatures approaching the ambient temperature. Additionally, depressed disinfectant residual,

elevated DBP levels, elevated bacterial counts, and elevated nitrite/nitrate levels may indicate water

quality issues with sampling and analysis of water in the tank. [39]

28

Bruce Rydbeck noted that the storage structures are normally built as concrete masonry unit (CMU)

structures. Tanks of volume greater than 30 cubic meters require a reinforced concrete base, concrete-

filled steel reinforced masonry block walls, and a slightly crowned lightened reinforced concrete cover.

The cover is lightened using lightweight concrete block in the pattern of a checker board. The CMU walls

are plastered by cement inside and out, and the inside plastering has special additives to improve the

waterproofing of the cement mortar. [40] This complies with the Ten States Standards recommendations

for protecting structures with a watertight roof in order to exclude animals and excessive dust pollution.

[35] The Ten States Standards recommendations for finished water storage structures also suggest fencing

around the structure to prevent trespassers, a drain in case of cleaning or emptying for maintenance

without loss of pressure in the connected distribution system, an overflow brought down to between 12

and 24 inches (about 30 to 60 centimeters) above the ground surface to discharge over a splash plate,

convenient access to the interior for cleaning and maintenance, and vents (not including the overflow).

[35]

29

5. WATER SYSTEM MODEL DEVELOPMENT A major part of the project is the development of the water distribution system using a number of

modeling programs. This allows system alternatives to be analyzed and tested under a variety of demand

conditions. The GPS information for the village was received as an AutoCAD file. Once the AutoCAD

file was imported into ArcMap, it could then be imported into EPANET for the model development. The

first step in developing this model is to check all the nodes with the AutoCAD file and mark whether they

are tank nodes, house nodes, or irrelevant. The irrelevant nodes are then deleted and the modeling begins.

Since there are some existing distribution tanks and a main line ending at the lower end of the

community, this was selected as the starting point for the design. The design will be based on a branching

network with little to no continuous loops. This design decision keeps the cost of piping down.

Secondly, this allows leaks to be detected more quickly than if the system had continuous loops.

5.1 Software

5.1.1 EPANET

EPANET is water distribution system modeling software developed by the United States Environmental

Protection Agency (EPA). Within the software, pipes, junctions (nodes), pumps, valves and storage tanks

- along with their user-defined properties - are used to form a model via EPANET’s graphical user

interface. From user input, the program simulates both steady-state and transient water flow models,

computing key system parameters such as flow, water pressure, and head loss. [41] All results can be

viewed in graphical or tabular format, making it beneficial for water system analysis and calculations.

5.1.2 Civil 3D to EPANET

The team received a full survey of Apatug from Cesar Cortez on October 20, 2014. The survey was

created in AutoCAD Civil 3D, and it included two meter topography contour lines, major roads, home

water connection locations, and the existing distribution line into the community. The AutoCAD drawing

was loaded into ArcMap 10.1 as a shapefile, and projected using North American Datum (NAD) 1983

Universal Transverse Mercator (UTM) Zone 17 South. Using GIS software, the coordinates and elevation

of each water house connection were extracted and loaded into a Microsoft Excel file. These coordinates

and elevations were used to create an input file for EPANET which represents each house connection in

Apatug as a separate node for modeling in EPANET. The nodes in the EPANET file are located at UTM

geographic coordinates and elevations that correspond to the survey provided by Mr. Cortez.

5.2 Materials and Properties The pipes in the Apatug network system will be designed as PVC pipes, with Plastigama specifications.

The Hazen Williams roughness coefficient for PVC pipe is 150. [34] One advantage of PVC pipe is its

high tensile strength (hydrostatic design basis = 26,400 kPa; E = 2,600,000 kPa). [42] One disadvantage

is that PVC pipe has a small maximum pressure of only 2,400 kPa which leaves little room for water

hammer strength. [42] High pipe strength is essential since high pressures will exist due to the great

elevation change. Water hammer will not be a major concern in the system because the number of large

valves will not be as great as in a typical water distribution system.

5.3 Design Values For this preliminary design, the team decided to use a daily per capita water usage as recommended by

the client of 120 L/person/day. This number will be corroborated by measuring actual usage on the trip to

30

Apatug in January. Taking 5 persons per household, and 500 households, this translates to a current total

daily usage of about 3.47 L/s, which is well under the spring constraint of 5 L/s. Using a 1.5% population

growth rate, as specified by Bruce Rydbeck, in 20 years, Apatug will require 4.68 L/s to satisfy average

daily demands. [43] The tank sizes were sized by taking 40% of the projected average daily need in 20

years for the number of households served within the respective pressure zones, rounded to the nearest 5

cubic meters. The highest elevation tank was given additional storage capacity in order to account for

potential additional growth to that sector and to provide the necessary volume for chlorination contact

times.

Peaking factors are assigned following the typical peaking factors previously noted. The maximum daily

demand peaking factor used is 2.0, and the peak hour peaking factor is 2.5.

5.4 Design Approach The model used groupings of five homes into one node to represent demands in the system. Pipe

connected the nodes making up different pressure zones throughout the village. These pipe networks

were then connected to their respective distribution tanks in order to regulate the pressure in each zone.

Pipes run down the main streets of the village to service most of the homes. The homes that are not on

the main streets will be served in the most convenient way to the village. This will take into consideration

the lay of the land and any existing fields or structures in the way of a direct route.

The system model is designed to perform under the peak hour condition 20 years from now, which is the

condition with the highest demand. Low pressure at nodes closer in elevation to the reservoirs are

mitigated by upsizing pipes leading to those nodes. This decreases headloss in the pipes. The maximum

allowable unit headloss is taken as 9 m/km; any pipe with greater unit headloss was upsized until it met

this requirement. At current average daily flows, the worst case for high pressures, the preliminarily

designed network keeps pressure below 60 meters at each point of water withdrawal as shown in Figure

11.

At 20 year peak hour flows, the worst case for low pressures, the preliminarily designed network keeps

pressure above 11 meters at each point of water withdrawl, which still satisfies project constraints as

shown in Figure 12.

31

Figure 11. Pressures in system under average day flows

32

Figure 12. Pressures in system under 20-year peak hour flows

33

The design also ensures that flow going into each tank is greater than the combined flow leaving each

tank because each tank is connected in parallel. It should be noted that model does not account for the

face that the flow going into to the first tank should not exceed the maximum of 5 L/s that Apatug has

rights to. Instead, the design shows what flows the system needs to provide the demand to each of the

households.

5.5 Future Design Testing

5.5.1 Current Design

The current design allows for each of the five pressure zones to be controlled by the head in the respective

tank. This allows for minimal change in head due to the fluctuation in the head of the tank. Currently, the

design consists of two pipes leaving the tanks, one to the respective pressure zone and another pipe acting

as a transmission main connecting the tanks. By doing this there are two pipes in some of the streets,

which may result in higher pipe costs. One possible change would be to connect the transmission main to

a lower end of the distribution system. The advantages and disadvantages to doing this are discussed in

the next section.

5.5.2 Possible Changes to Design

Some possible changes to the design that will be considered after the team’s trip to Ecuador are as

follows. The placement of reservoirs inside the community are going to involve a lot of community

participation as to where land could be bought. Currently the ACE Team has elevations where the tanks

should be placed in order to regulate the pressure properly and proposed locations in the village. These

locations would need to be approved by the village to make them permanent in the design. The locations

of the tanks is going to affect the transmission mains in between the tanks, which could significantly

affect the design.

If the tanks are close enough to the top of the pressure zone it services, it may be possible to have the

transmission main service the pressure zone itself. The problem with this approach arises when the top of

the pressure zone is closer to the end of the transmission main than it is to the beginning of the

transmission main. This is a problem because the Hydraulic Grade Line (HGL) of the transmission main

is a straight line from the water surface elevation of the higher tank to the water surface elevation of the

lower tank. If the pressure zone is connected on the lower half of the transmission main then this will

cause greater variations in pressure since the starting HGL associated with the zone would be the

transmission main. However, if the pressure zone is connected to the upper half of the transmission main,

this pressure drop will not be as severe because of the lower drop in the tank’s HGL compared to the

transmission main’s HGL. Figure 13 gives a representation of how the different connection approaches

are affected by the two different HGL’s.

34

Figure 13. Representation of Pressure Variation due to Different HGL's

The current system’s pressure zones are connected to the tanks directly to eliminate this drop in pressure.

One of the problems with this would be the need for increased lengths of pipe since there is a

transmission main connecting tanks and a main line that feeds the pressure zones. Looking ahead, one of

the tests to the current design that will need to be done is to see if it would work to run one main from

each tank to the top of the pressure zones and from there start the transmission main leading to the next

tank.

Additionally, a transient analysis could be performed to monitor prospective tank level variations, which

could affect the design elevation and design tank levels.

35

6. CHLORINATION BENCH STUDY A bench scale study of the chlorine dosing injector pumps is scheduled for the second semester of the

project. By testing the ability of selected injector pumps to deliver a dose that responds well to changes in

flow rate, the team will be able to better recommend a dosing pump for use in the chlorination system in

Apatug.

Fluid-driven proportional injectors are used throughout the industries of agriculture, food service, and

farming to ensure the precise administration of water soluble chemicals to a water supply. Currently, there

is no precedent set for the sustained treatment of a municipal water supply using this technology. Water

quality standards are much more stringent for humans than they are for livestock and crops, thus due

diligence must be performed before deployment can begin. The purpose of the bench scale study is

twofold: (1) to become familiar with the operations of the selected injector, its setup, and maintenance

and (2) to establish if the injector creates the anticipated chlorine residual by responding to changes in

flow. Figure 14 shows the preliminary process design of the bench scale study.

Figure 14. Bench Scale Design

The first step will be to run a control test with deionized water and 5% NaOCl to get a chlorine residual

concentration of 0.3 mg/L. Once the system is calibrated the deionized water will be replaced with water

treated to match the conditions of that in Apatug. The system experiment will be recalibrated and repeated

to develop the 0.3 mg/L residual suggested by Bruce Rydbeck. After calibration, the flows will then be

varied to test how well the injector responds and if the residual can maintained. Finally, any dosing

calculations that were made to theoretically calibrate the injector will be modified to more accurately

reflect the water composition in Apatug.

36

7. TRIP TO ECUADOR The ACE Team will travel to Ecuador during January. This trip will be separated into two components,

with two team members traveling from January 19-January 31, and two more from January 24-January

31. The second pair cannot travel for the full two weeks due to an interim special topics course which is

required for graduation. The first pair of students to travel, Wendy and Julie, will meet up with the ACE

Team’s client, Bruce Rydbeck, and tour Apatug to determine the best location for reservoirs and other

proposed structures as well as connecting with members of the Apatug community. When the second pair

of Mark and Nathan arrives, the four team members, along with Mr. Rydbeck, will travel around to other

current water and chlorination systems to get a better understanding for the methods that are most

successful in similar settings. These community visits will allow the four members of the group to get a

better understanding for what is culturally appropriate as the system is finalized and chlorination design

begins. The team will do some chlorine monitoring while also looking at the chemical make-up of the

water in Apatug, so conditions can be duplicated for the bench-scale model the team hopes to build. The

trip will also allow the group to make a personal connection with the community. Asking the community

leaders for input in regards to reservoir location is important in the success of the system as the

community becomes involved and they feel more responsible for the system, increasing the chance that

the system is maintained and is reliable for years to come.

7.1 Trip Goals There are two important reasons for the team to travel to Ecuador and visit the community of Apatug.

First, testing of the source water quality in Apatug is needed to determine chlorine dosing requirements.

Second, a trip to Apatug will be crucial in the sustainability of the design, which requires community

involvement and ownership. This water distribution system is scheduled to be implemented after the

completion of the design recommendation, and for the system to be sustainable, ownership and

investment from Apatug is extremely important.

Specific goals for the trip include:

1. Implementation of water testing in Apatug to determine chlorine dosing requirements

2. Tour of local chlorination systems

3. Investigate local electrolysis equipment used for chlorine production

4. Meet with the community and establish a positive, working relationship

5. Select potential reservoir locations and confirm pipe network layout

6. Learn local construction methods and materials

7. Gather any cultural information relevant to the final design

7.2 Tentative Itinerary

January 19 Wendy and Julie arrive in Quito

20 Design meeting in Quito in the morning and then leave for Apatug

20-22 Work in Apatug on information gathering, meet with the community to discuss layout of

proposed structures, etc.

23 Leave Apatug by noon for Quito to pick up Nathan and Mark

24 Visit the Indian market in Otavalo and then tour the Carabuela water system and take

chlorine measurements

25 Sunday - attend worship service and do some sightseeing in Quito

37

26 Leave for Apatug for final day of work in the community

27 Tour of local water lab in Cajabamba and chlorine production facilities

28-30 Tour of community water systems in several communities and chlorine monitoring

30 Return to Quito

31 Leave for the U.S.

The team will be hosted by Bruce Rydbeck and Cesar Cortez, who will accompany the team during the

duration of the trip. [44]

7.3 Water Testing Plan

7.3.1 Purpose

Performing field water testing while in Ecuador will be important in determining source water quality and

composition, both of which are critical in chlorine dosing for effective disinfection. Having an accurate

representation of the chemical composition of the source water will be useful in performing a chlorination

bench study. In addition, knowledge of source water quality, turbidity, pH, and temperature fluctuations

are imperative for effective chlorine dosing.

7.3.2 Objectives

1. To determine the bacterial concentration of the protected spring water that supplies the

community of Apatug with drinking water.

2. To determine the chemical composition of the protected spring water for the purposes of chlorine

dosing and bench study design.

3. To determine the turbidity, pH, and temperature of the protected spring water to calculate

chlorine dosing for sufficient disinfection.

4. To perform water quality measurements under a variety of conditions, including high and low

flow and different times of day to more accurately determine daily fluctuations in water quality, if

any.

7.3.3 Key Parameters

1. Natural Organic Matter (NOM)

NOM is typically measured by filtering the water sample and analyzing the sample for Total

Organic Carbon (TOC). TOC measurement requires expensive field equipment, but a turbidity

measurement can be an indicator of the concentration of organic solids in water. NOM

concentration is relevant in determining proper chlorine dosing because chlorine reacts with

NOM to form byproducts. [45]

2. Turbidity

Turbidity, measured in NTU, is an indicator of suspended solids and colloids concentration in a

liquid. Measured by quantifying the amount of light that is able to pass through a water sample,

turbidity is especially important in determining the effectiveness of UV disinfection. However,

turbidity also impacts disinfection efficiency, with higher turbidity levels resulting in lower free

chlorine concentration due to the oxidation of organic matter. [45] Turbidity meters can be

purchased and used in the field, costing in the range from $1000 to $2000 from Hach Company.

38

Alternatively, a Secchi disk method can be used to visually determine turbidity. As shown in

Figure 15, a Secchi disk is placed at the bottom of a clear tube which is filled with sample water

until the Secchi disk can no longer be seen. The depth of the sample water corresponds to the

turbidity of the sample. Secchi disks are inexpensive to construct, but they do not provide the

same accuracy as the manufactured turbidity meters.

Figure 15. Schematic of a Secchi Disk as a Turbidity Measurement [46]

The pH of water is a measure of the acidity or basicity of an aqueous solution. pH affects the

efficiency of chlorine disinfection, with lower pH being more efficient for disinfection.

According to U.S. Army Public Health Command, source water pH should be below 8 for

effective chlorination. [45]

3. Temperature

Chlorine disinfection is also affected by the temperature of the source water, with higher

temperatures yielding faster disinfection. [45]

39

4. Ammonia

Ammonia reacts with chlorine in water, affecting the amount of free chlorine available for

disinfection. [47] Ammonia concentration can be measured using a Hach Water Testing Kit.

5. Coliforms

Bacterial coliforms give an indication of potential pathogenic bacteria that pollute drinking water

sources. [48]

6. Hydrogen sulfide

Hydrogen sulfide reacts with chlorine, reducing its effectiveness as a disinfectant. [46] Hydrogen

sulfide is also an indicator of pathogenic bacteria, as it is produced by fecal coliforms. [46]

7.3.4 Field Test Plan

Since the community of Apatug currently receives all of its drinking water from a single protected spring,

the spring water delivered to the village through the existing feedline shall be tested for relevant water

quality parameters.

Test Parameters

1. Turbidity, 6 grab samples

2. Temperature, 6 grab samples

3. pH, 6 grab samples

4. Ammonia, 2 composite samples (6 water samples collected over 2 days)

5. Hardness, 2 composite samples (6 water samples collected over 2 days)

6. Chloride, 6 grab samples

7. Alkalinity, 2 composite samples (6 water samples collected over 2 days)

8. Bacterial coliforms, 6 grab samples

9. Hydrogen sulfide, 2 composite samples (6 water samples collected over 2 days)

The source water will be tested in the morning, in the afternoon, and at night to represent current drinking

water at different times of the day, including during high and low water demand. Water quality analysis

tests will also be performed on three different days to provide an idea of the range of chemical and

bacterial concentrations of the source water. The schedule and times of the water testing may be altered

after visiting the village and determining more accurate water usage patterns. In total, a minimum of nine

tests for each parameter are needed to compete the water survey.

Equipment and Cost Equipment sources and costs are summarized in

Table 3.

40

Table 3. Water Testing Equipment and Cost Estimates.

Test Parameter Equipment Source Estimated Cost

Gloves Calvin College --

Plastic test tubes Calvin College --

Turbidity Secchi disk and tube Self-constructed $ 5

Temperature Nine-Parameter Test Kit

Model FF-1A

Hach

$ 299

pH

Ammonia

Hardness

Chloride

Alkalinity

Bacterial coliforms Petrifilm Coliform

Count Plates

3M $ 55

Hydrogen sulfide H2S Test Kit Hach $ 25

Total Estimated Cost $ 384

41

8. PROJECT FEASIBILITY CONCLUSION

8.1 Cost Analysis The following is a detailed cost analyses of the proposed distribution system to date, December 6, 2014.

8.1.1 Distribution System Cost

Table 4 shows a summary of the different pipe diameters that have been selected in the current design up

until this point. The unit cost of PVC pipe from a similar project can be seen in Table 5. These prices are

just preliminary, when the design is finalized current unit prices will be obtained from Bruce Rydbeck.

An estimate at the total cost given the rough lengths and prices shown below would be $52,317.31.

Home connections will need to be made wherever possible. However, it is unknown how many home

connections will be made or how many spigots that translates into for the homes without indoor

plumbing. A more detailed cost analysis will be given in the design report.

Table 4. Preliminary Pipe Lengths Estimate

Nominal Diameter

(mm)

Inner Diameter

(mm)

Total Length

(m)

40 36.2 4487

50 45.2 2912

63 57 2877

75 69.2 1866

TOTAL 12142

Table 5. Unit Cost of Similar Projects [49]

Nominal Diameter

(mm) Unit Cost (US$/m)

40 2.69

50 3.60

63 5.52

75 7.44

8.1.2 Chlorination Dosing System Cost

Table 6 shows the preliminary cost of the chlorine dosing system. These costs will be finalized and more

detail will be made available after the trip to Apatug in January 2015.

42

Table 6. Preliminary Dosing System Cost Estimate

Parts List Cost

MiniDos Injector 12gpm $550.00

PVC Compression Stop & Waste Valve (Inlet Valve) $8.95

Outlet Valve (Same as above) $8.95

Water Hammer Arrestor, 3/4 In MNPT, Copper $45.60

Suction Tube $2.00

4 in. x 4 in. x 3/4 in. Schedule 40 PVC Reducing Tee X 2 $27.92

Joints and other fittings $100.00

Contingency $74.34

Total $817.76

8.2 Sustainability Study The National Research Council has defined a sustainable water system as follows:

“A sustainable water system is one that can meet performance requirements over the long

term. Such systems have the following characteristics (Wade Miller Associates, 1991;

Okun, 1995): a commitment to meet service expectations; access to water supplies of

sufficient quality and quantity to satisfy future demand; a distribution and treatment

system that meets customer expectations and regulatory requirements; and the technical,

institutional, and financial capacity to satisfy public health and safety requirements on a

long-term basis. Like any good business, a sustainable water system can also adapt to

future changes in regulatory requirements and customer demand.… Achieving

sustainability is not a onetime task; it requires a continuous effort.” [12]

Furthermore, Breslin, CEO of Water For People, states that project “success will require less single-

minded focus on the absolute number of people without access to water and sanitation facilities and more

focus on the serious questions around long-term impact and sustainability.” [13] This water distribution

system and chlorination dosing system will be designed in a way that achieves this criterion.

One of the main ways that Apatug’s system will be designed for future sustainability will be to place all

main lines in the street. When it is fit to do so, a main line will divert off of the street to service homes.

But this will only be done in cases where it is deemed necessary; when five or more homes are not on a

main road. For all other cases, the homes will have direct connections off of the main line in the street.

By laying the majority of the pipe for the system in the already established streets, it allows for natural

growth of the community of Apatug without any need to reallocate pipelines. Since agriculture is a large

43

part of the community of Apatug, the fields will not see any adverse effects as to implementation of this

distribution system. Placing pipes in the street also minimizes disturbance to existing buildings and fields,

and it will not occupy spaces that are likely be developed in the future.

Creating a water distribution system is a step towards a sustainable development for Apatug. However,

the design must also be sustainable overall. For the design to be sustainable, it must be reliable and last a

long time with minimal required maintenance. Some of the design decisions that are affected by

reliability are as follows: reservoir design, pipe diameter and thickness, and chlorination dosing method.

The chlorination dosing is a major component of reliability, because if the dosing mechanism does not

work properly, the water that is received in homes will not be properly disinfected. Failure to dose

effectively would result in inadequate disinfection and would not be following the Ecuadorian law

requiring chlorination. [24] If pipes are too small or the pipe wall is too thin, they will experience too

much pressure and rupture.

This design needs to be sustainable in its cost effectiveness as well. Cost of materials could have a

significant impact on the frequency and manner of maintenance of the system. The selection of materials

needs to be made with cost in mind, as well as strength, in order to prevent future breaks in the system.

Whereas communities in the United States rely on taxpayer money and public works programs, Apatug

does not have the infrastructure in place to give maintenance responsibilities to a third party. By

designing the system with cost in mind it will be sustainable for the village and will not be a crippling

blow if a fix needs to be made.

Because Apatug is a rural community, the need for environmental stability needs to be met as well. Some

of the villagers work in fields within the community to make their living. The design and construction

needs to be completed in a way that does not significantly affect the environment or landscape. When

selecting materials to use, this will be a key aspect. The pipes will need to be joined together in the

construction process in a way that is clean and does not leave behind any unwanted environmental

hazards.

Community trust in the system and especially in the chlorination are major factors in the sustainability of

the system. If the community does not trust the chlorination because it affects the taste, then the system

most likely will not fulfill its potential. Community trust is one of the major factors in the success of a

rural water distribution system. Most communities throughout the world have some sort of political

structure that makes major decisions for the community. Working through and understanding this

political structure instead of forcing the design on the community can have a major impact on whether the

project is a success. [24] One of the main components of this design is working with the community to

decide where the reservoirs should be placed. If the community does not trust the system, then it will not

be used as intended and lose the sustainability factor in return.

8.3 Distribution System Design In order to control pressures in the system and supply each household with clean water, the team proposes

a distribution network preliminary design, as detailed and shown in Appendix E. The team has designed

the system using five reservoirs to control five pressure zones, in order to maintain adequate pressures in

the range of 20 to 60 meters at the household connections. This was chosen over the use of PRVs

throughout the system to provide a reliable, flexible, and sustainable distribution network. The team then

created a preliminary model in EPANET that can be updated and changed based on interactions with the

44

community in January. The design based on this model will then be corroborated with Church’s tabular

method to illustrate its consistency with commonly used methods. The currently proposed lengths of

pipes of each diameter can be found in Table 4.

More testing and final design will be performed in the coming semester after more information is

gathered from the community and its leaders in January.

8.4 Proposed Chlorination System After evaluating chlorination alternatives, the team selected liquid sodium hypochlorite as the disinfection

chemical for the Apatug system. Liquid hypochlorite is widely available in Ecuador and leaves residual

chlorine in the distribution system when dosed properly. The chlorine dosing system will consist of a

chlorination building to house the chlorine solution, dosing injector pumps, and other necessary valves

and operating equipment, including chlorine test strips and check valves. The chlorination building will

receive water from the main pipeline from the protected springs, dose the chlorine solution into the spring

water, and transport the chlorinated water to a reservoir, which will also serve as a contact tank. A

preliminary drawing of the chlorine dosing building is included in Appendix F. A process flow diagram

of the chlorination system is shown in Figure 16.

Figure 16. Process Flow Diagram for Chlorine Dosing.

Initial calculations, included in Appendix G, assuming a flow range of 1 to 5 L/s, a minimum water

temperature of 50 °F, and a maximum pH of 8, were used to determine an effective volume necessary for

the contact tank of 16 m3. The required volume for the contact tank will be determined by the contact time

necessary for disinfection of the source water. Field chemical analysis and water quality tests performed

45

in Apatug will be necessary to determine a more accurate contact time and tank volume needed in the

system.

The proposed reservoir at the highest elevation is recommended to be 3490 m, which will also be the

elevation of the dosing station and contact tank. However, the dosing system will not be greatly affected

by its elevation, provided there is a sufficient amount of head to drive water through the dosing pump.

The last distribution tank located on the existing pipeline from the springs before reaching Apatug is at an

elevation of 3521 m, which will provide a sufficient amount of pressure to drive flow through a pump at

3490 m.

Initial flow calculations through the dosing injector pump were performed using specifications from

MixRite 3.5, a proportional flow fluid-driven injector pump. Using these specifications and a 5% solution

of sodium hypochlorite, it was determined that a shunt flow of 0.02 to 0.10 L/s is needed to drive the

injection pump. Using this initial shunt flow calculation, a chlorine dose ranging from 1:2114 to 1:503

would be provided by the injector pump, which is consistent with the specifications from the MixRite 3.5,

included in Appendix D.

46

9. BASIS OF DESIGN

9.1 Distribution System Design The preliminary distribution network model is provided in the AutoCAD plot in Appendix E. A summary

of pipe diameters and lengths, as well as the size of the proposed reservoirs, is provided in Error!

Reference source not found.. Apatug has been divided into five pressure zones to keep pressure within

the 20-60 meter range. Each node on the network represents five homes and there are about 100 nodes

total. Geographical information from a survey done of Apatug was converted into an AutoCAD file.

Based on the AutoCAD file a model was created EPANET 2.0, as seen in Figure 17. The EPANET file

can be found at the team’s website at: www.calvin.edu/academic/engineering/2014-15-team19.

Figure 17. EPANET Model of Apatug with Elevations

47

Table 7. Summary of Distribution System Components

9.2 Chlorination System Design Dosing of chlorine will be performed by a fluid-driven proportional injector calibrated to deliver a

residual of 0.3 mg/L. This type of pump is preferred for Apatug because it can maintain a constant

residual through the 1-5 L/s flow range. A shunt off the main water line will necessary to motivate the

injector. After mixing, the water requires a sufficient contact time inside of a reservoir to get full kill of

pathogens. The first reservoir at a volume of 20 m3 will serve as the contact tank.

9.3 Chlorination Bench Scale Study The bench scale study will be performed in Calvin College’s Environmental Engineering Research lab. A

preliminary schematic of the design is provided in Figure 14. Most of the equipment will be provided by

Calvin College except for the fluid-driven injector which will be purchased by the team. The water used

for the experiment will be created to match water samples taken during the team’s trip to Ecuador in

January.

9.4 Future Work The next step for the ACE Team is to travel to Apatug in January of 2015. While in Apatug, the team will

meet with the community to finalize the water distribution network layout and reservoir placement. Water

quality and chemical analysis tests will also be performed to inform the chlorination dosing design. The

trip to Ecuador will also provide an opportunity for the team to communicate with the community of

Apatug, in keeping with the design norms of cultural appropriateness and transparency.

The spring semester will consist of detailed plans for the water distribution system, including final pipe

layout, reservoir design and placement, connections, valves, and the installation of water meters. A bench

study will also be performed to select a dosing method for chlorine disinfection. A detailed plan for the

chlorination system will also be formulated in the spring.

Reservoir Size

(m3) Count

Nominal Pipe

Diameter (mm)

Length of Pipe

(m)

15 1 40 4487

20 1 50 2912

35 1 63 2877

40 1 75 1866

55 1

Total Count 5 Total Length 12142

Pipe NetworkReservoirs

48

10. AKNOWLEDGEMENTS The ACE team would like to formally thank the following individuals for graciously offering their time

and knowledge to the success of this project:

David Wunder of the Calvin College Engineering Department, for offering his insight and advice to the

team on a weekly basis; Robert Hoeksema of the Calvin College Engineering Department for offering his

expert knowledge of EPANET and guiding the team through the entire process of distribution system

modeling; Bob DeKraker of the Calvin College Engineering Department for assistance in installing

modeling software; Tom Newhof Sr. of Prein&Newhof for meeting with and advising the team as an

industrial consultant; Bruce Rydbeck of Life Giving Water International for providing this project to us,

coordinating our trip to Ecuador in January, and supplying the team with information to make this project

successful; and Cesar Cortez of Reach Beyond for providing GPS data of Apatug and answering the

questions of the team.

49

11. REFERENCES [1] "Calvin College Engineering," [Online]. Available:

http://www.calvin.edu/academic/engineering/about/mission.html.

[2] B. Rydbeck, [Email Correspondence]. 15 October 2014.

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for Action 'WATER FOR LIFE' 2005-2015," 5 May 2014. [Online]. Available:

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2014].

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http://www.un.org/millenniumgoals/environ.shtml. [Accessed 5 December 2014].

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http://pdba.georgetown.edu/Constitutions/Ecuador/english08.html. [Accessed 20 September

2014].

[8] B. Rydbeck, [Email Correspondence]. 19 September 2014.

[9] B. Rydbeck, [Email Correspondence]. 27 November 2014.

[10] J. C. Church, Practical Plumbing Design Guide, New York: McGraw-Hill, Inc., 1979.

[11] World Bank, "World Development Indicators," [Online]. Available:

http://data.worldbank.org/data-catalog/world-development-indicators. [Accessed 2 November

2014].

[12] National Research Council (U.S.), Safe Water from Every Tap: Improving Water Service to

Small Communities, Washington D.C.: National Academy Press, 1997.

[13] E. D. Breslin, "Rethinking Hydro-Philanthropy: Smart Money for Transformative Impact,"

Journal of Contemporary Water Research & Education, vol. 145, no. 1, pp. 65-73, 2010.

[14] D. A. Okun, "A Water and Sanitation Strategy for the Developing World," Environment, vol. 33,

no. 8, pp. 20, 39-40, 1991.

[15] G. Pearce-Oroz, "Rural Water Supply and Sanitation Challenges in Latin America for the Next

Decade," in Cusco+10, Lima, Peru, 2011.

[16] M. Munasinghe, "The pricing of water services in developing countries," Natural Resources

Forum, vol. 143, 1990.

50

[17] A. Gadgil, "Drinking water in developing countries," Annual Review of Energy and the

Environment, vol. 23, no. 253, pp. 282,284, 1998.

[18] J. Briscoe and D. M. De Ferranti, Water for rural communities: helping people to help

themselves, Washington, D. C.: World Bank, 1988.

[19] S. P. Andey and P. S. Kelkar, "Influence of intermittent and continuous modes of water supply on

domestic water consumption," Water Resources Management, vol. 23, no. 12, pp. 2555-2566,

2009.

[20] US Environmental Protection Agency Office of Water, "2006 Community Water System

Survey," 2009.

[21] J. Guerrero, C. Kluge, M. Spee and J. Voogt, "Senior Design Final Report: Water Systems

Design for Cajabamba, Ecuador," Calvin College, Grand Rapids, MI, 2008.

[22] A. Braghetta, "Drawing the connection between Malnutrition and lack of safe drinking water in

Guatemala," American Water Works Association, vol. 98, no. 5, pp. 97-106, 2006.

[23] M. M. Mao, K. J. Zhang, T. Q. Zhang and H. L. Yu, "Research Progress of Typical Taste and

Odor Compounds Produced by Chlorination in Drinking Water," Applied Mechanics and

Materials, p. 698, 2013.

[24] Ecuadorian Standardization Institute, "Drinking-water Requirements," NTE INEN 1108, 2010.

[25] L. A. McLaughlin, K. Levy, N. K. Beck, G. A. Shin, J. S. Meschke and J. N. Eisenberg, "An

observational study on the effectiveness of point-of-use chlorination," Journal of Environmental

Health, vol. 71, no. 8, pp. 48-53, 2009.

[26] International Programme on Chemical Safety, "2. Chemistry of Disinfectants and Disinfectant

By-products," in Environmental Health Criteria 216: Disinfection and Disinfectant By-products,

Geneva, World Health Organization, 2000, pp. 27-109.

[27] Food & Water Watch, "Chloramine: A Chlorine Alternative in Drinking Water Fact Sheet,"

Vermonters for a Clean Environment, April 2010. [Online]. Available:

http://www.vce.org/FWWchloramine.pdf. [Accessed 14 October 2014].

[28] National Academy of Sciences, "Treatment: Chemical Disinfection/ Oxidants Technologies,"

Drinking-Water.org, 2008. [Online]. Available: http://www.drinking-

water.org/html/en/Treatment/Chemical-Disinfection-Oxidants-technologies.html. [Accessed 14

October 2014].

[29] B. Rydbeck, [Email Correspondence]. 9 October 2014.

[30] "Electrochemistry: Interactive Student Tutorial," Prentice Hall, [Online]. Available:

http://wps.prenhall.com/wps/media/objects/4680/4792445/ch18_12.htm. [Accessed 7 November

2014].

51

[31] United States Environmental Protection Agency, "4. Chlorine Dioxide," in EPA Guidance

Manual: Alternative Disinfectants and Oxidants, U.S. EPA, 1999, pp. 4-1 - 4-41.

[32] Dosmatic, "The Dosmatic Advantage Operation and Installation Manual for All A15 Models,"

HydroSystems, 2001.

[33] B. V. Rydbeck and B. Vander Plas, "Rural Water System Disinfection Pilot Project for

Carabuela, Ecuador," 2013.

[34] Tubosistemas Plastigama de Amanco, "Tuberias y accesarios de PVC y PE BD Uso Agricola".

[35] Great Lakes Upper Mississippi River Board of Water, Recommended Standards for Water

Works, 1992.

[36] American Water Works Association, Distribution Network Analysis for Water Utilities M32,

Denver, CO: American Water Works Association, 1989.

[37] B. Rydbeck, [Email Correspondence]. 9 September 2014.

[38] L. W. Mays and T. M. Walski, "Hydraulic Design of Water Distribution Storage Tanks," in

Water Distribution Systems Handbook, New York, McGraw-Hill, 2000, p. 10.1.

[39] Environmental Protection Agency, 15 August 2002. [Online]. Available:

http://water.epa.gov/lawsregs/rulesregs/sdwa/tcr/upload/2007_05_18_disinfection_tcr_whitepape

r_tcr_storage.pdf. [Accessed 26 November 2014].

[40] B. Rydbeck, [Email Correspondence]. 4 November 2014.

[41] United States Environmental Protection Agency, "EPANET," U.S. EPA, 8 July 2014. [Online].

Available: http://www.epa.gov/nrmrl/wswrd/dw/epanet.html. [Accessed 10 October 2014].

[42] L. W. Mays, Water Resources Engineering, Second ed, United States: John Wiley & Sons, Inc.,

2010.

[43] B. Rydbeck, [Email Correspondence]. 13 November 2014.

[44] B. Rydbeck, [Email Correspondence]. 18 November 2014.

[45] U.S. Army Public Health Command, "Chlorine Disinfection in the Use of Individual Water

Purification Devices: Technical Information Paper #31-002-0306," phc.amedd.army.mil.

[46] J. Kearns, "Simple Field Tests for Water Quality," Aqueous Solutions, January 2008. [Online].

Available: http://www.aqsolutions.org/images/2008/01/simple-field-tests-for-water-quality.pdf.

[Accessed 5 November 2014].

[47] Fisheries and Aquaculture Department, "Chapter 2 - Water Quality Monitoring, Standards, and

Treatment," Food and Agriculture Organization, 2013. [Online]. Available:

http://www.fao.org/docrep/x5624e/x5624e05.htm#2.2.3 bacteriological tests. [Accessed 5

November 2014].

52

[48] "Chlorine, Coliform, and pH Test Kit, Model CEC-2 (with 120 Vac UV Lamp and Incubator,"

Hach Company, 2014. [Online]. Available: http://www.hach.com/chlorine-coliform-and-ph-test-

kit-model-cec-2-with-120-vac-uv-lamp-and-incubator/product?id=7640249600. [Accessed 5

November 2014].

[49] M. A. Niskanen, "The Design, Construction, and Maintenance of a Gravity-Fed Water System in

the Dominican Republic," Michigan Technological University, 2003.

[50] B. V. Rydbeck and M. Yamez, "Sustainable Water Quality for Rural Ecuadorian Communities,"

2012.

[51] P. G. Bourne, Water and Sanitation Economic and Sociological Perspectives, Orlando: Academic

Press, Inc., 1984.

A-1

Appendix A – Gantt Chart

ID Task

Mode

Task Name Duration Start Finish

1 Project Proposal 6 days Wed 9/3/14 Wed 9/10/14

2 PPFS Outline Draft 11 days Thu 9/11/14 Thu 9/25/14

18 Chlorination Research 11 days Tue 10/7/14 Tue 10/21/14

19 Distribution Research 11 days Tue 10/7/14 Tue 10/21/14

21 Apatug & Ecuador Research 11 days Tue 10/7/14 Tue 10/21/14

8 Assign Project Roles 3 days Wed 10/8/14Fri 10/10/14

22 Design Logo 3 days Wed 10/8/14Fri 10/10/14

28 Material Availability Research 6 days Wed 10/8/14Wed 10/15/14

29 Special Topics Proposal 6 days Wed 10/8/14Wed 10/15/14

5 Oral Presentation I 4 days Wed 10/15/14Mon 10/20/14

14 Project Brief 4 days Wed 10/15/14Mon 10/20/14

15 Team Photos 4 days Wed 10/15/14Sun 10/19/14

30 January Trip Planning 38 days Thu 10/16/14Mon 12/8/14

16 PPFS Draft 1 6 days Mon 10/20/14Sun 10/26/14

23 GIS and Survey to EPANET 6 days Mon 10/20/14Sat 10/25/14

4 Chlorine Decision Matrix 6 days Mon 10/27/14Sun 11/2/14

10 Project Poster 5 days Mon 10/27/14Fri 10/31/14

11 PPFS Draft 2 6 days Mon 10/27/14Sun 11/2/14

24 Preliminary EPANET Model 31 days Mon 10/27/14Sun 12/7/14

3 Dosing Decision Matrix 6 days Mon 11/3/14Sun 11/9/14

9 Project Website 11 days Mon 11/3/14Mon 11/17/14

13 PPFS Draft 3 6 days Mon 11/3/14Sun 11/9/14

20 Water Testing Plan for January 6 days Mon 11/3/14Mon 11/10/14

7 Industrial Consultant Meeting 5 days Tue 11/4/14 Mon 11/10/14

31 Bench Study Design 24 days Wed 11/5/14Sun 12/7/14

12 PPFS Total Draft and Review 6 days Mon 11/10/14Mon 11/17/14

17 PPFS Final 20 days Tue 11/11/14Mon 12/8/14

25 Reservior Design Research 16 days Wed 11/12/14Wed 12/3/14

26 Unit Cost Estimate 4 days Wed 11/12/14Mon 11/17/14

6 Oral Presentation II 3 days Thu 11/20/14Mon 11/24/14

27 Cost Estimate 7 days Fri 11/28/14 Sun 12/7/14

32 Preliminary AutoCAD Drawing 4 days Wed 12/3/14Sun 12/7/14

T W T F S S M T W T F S S M T W T F S S M T

Sep 7, '14 Sep 14, '14 Sep 21, '14

Task

Split

Milestone

Summary

Project Summary

Inactive Task

Inactive Milestone

Inactive Summary

Manual Task

Duration-only

Manual Summary Rollup

Manual Summary

Start-only

Finish-only

External Tasks

External Milestone

Deadline

Progress

Manual Progress

Page 1

Project: ProjectDraft1

Date: Mon 12/8/14

W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S

Sep 28, '14 Oct 5, '14 Oct 12, '14 Oct 19, '14 Oct 26, '14 N

Task

Split

Milestone

Summary

Project Summary

Inactive Task

Inactive Milestone

Inactive Summary

Manual Task

Duration-only

Manual Summary Rollup

Manual Summary

Start-only

Finish-only

External Tasks

External Milestone

Deadline

Progress

Manual Progress

Page 2

Project: ProjectDraft1

Date: Mon 12/8/14

S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W T F S S M T W

Nov 2, '14 Nov 9, '14 Nov 16, '14 Nov 23, '14 Nov 30, '14 Dec 7, '14

Task

Split

Milestone

Summary

Project Summary

Inactive Task

Inactive Milestone

Inactive Summary

Manual Task

Duration-only

Manual Summary Rollup

Manual Summary

Start-only

Finish-only

External Tasks

External Milestone

Deadline

Progress

Manual Progress

Page 3

Project: ProjectDraft1

Date: Mon 12/8/14

B-1

Appendix B – Disinfection Decision Matrices

Figure B.1. Decision Matrix for Chlorine Dosing Method

Figure B.2. Decision Matrix for Disinfection Chemical

C-1

Appendix C – Pressure Zone and Tank Mathcad and Excel Calculations Calculations: Wendy Tabler 11/6/14

Checked By: Jeremy Kamp 11/7/14

20-60 meter range (5 Zones)

head min max # households

3326 3266 3306 46

3367 3307 3347 125

3408 3348 3388 167

3449 3389 3429 102

3490 3430 3470 18

Reservoir Sizing Size (m3)

Zone 1 (Lowest Elevation) 15

Zone 2 40

Zone 3 55

Zone 4 35

Zone 5 (Highest Elevation) 20

D-1

Appendix D – Injector Pump Specifications for MixRite and Dosmatic®

D-2

D-3

D-4

D-5

E-1

Appendix E – Distribution System Schematic

F-1

Figure F.1. Preliminary Chlorine Dosing Station Schematic

Appendix F – Chlorine Dosing Station Schematic

G-1

Appendix G – Chlorine Dosing Mathcad Calculations

Apatug Chlorine Dosing

Calculations: Julie Swierenga 12/3/14

Checked By: Nathan Laframboise 12/5/14

Assumptions

Flow range into chlorine dosing station: 1 – 5 L/s (15 – 79 gpm) [email from Bruce 9/19/14]

Chlorine dosing range: 0.5 – 2 ppm [email from Bruce 9/19/14]

Hypochlorite solution at 5% (1 mol NaOCl to 1 mol free chlorine)

0.3 mg/L free chlorine residual is desired [Rydbeck, Chlorination Pilot Study, 2013]

Highest estimated water pH: 8.0

Lowest estimated water temperature: 50 °F

Highest pH and lowest temperature were used to determine necessary contact time [Cornell,

Chlorination of Drinking Water Factsheet, 2005]

Desired 99.9% removal of giardia and 99.99% removal of viruses

Shunt flow and dosing calculations will be compared to pump specifications for the MixRite 3.5

G-2

Dosing Station

elevation : 3500 - 3510m pressure upstream: 11-21 mH2O

contact tank volume: 16 m3 flow: 1-5 L/s chlorine strength = 5% NaOCl or 50000 ppm

Contact Time

contact Time (CT) in min constant from Cornell Factsheet (k) residual chlorine (r) in (mg/L)

Tank Volume

peak flow

tank volume (v) in m3

Chlorine Dosing

Chlorine dose in relation to flow

0.02 L/s : 9.46 x 10 -6 = 1 : 2114

0.10 L/s : 1.99 x 10 -4 = 1 : 502.5

k 16 r .3

CTk

r53.333

q 5l

s

v CT q 60 s 1.6 104

L v 16 m3

qlowflow 15gpm

strength chlorine.low.5

500001 10

5

chlorinedose.low qlowflow strength chlorine.low 9.464 106

l

s

qhighflow 79gpm

strength chlorine.high2

500004 10

5

chlorinedose.high qhighflow strength chlorine.high 1.994 104

l

s