FINAL DESIGN REPORT
Team 19
Mark De Haan
Jeremy Kamp
Nathan Laframboise
Julie Swierenga
Wendy Tabler
9 May 2015
Calvin College
Engineering 339/340: Senior Design
Copyright © 2015, Calvin College, Mark De Haan, Jeremy Kamp, Nathan Laframboise, Julie
Swierenga, and Wendy Tabler
Executive Summary
The ACE Team has completed a multi-year distribution system improvement plan and disinfection pilot
study for the community of Apatug. These two documents will outline improvements that can be made to
the current water distribution system to reach 100% functionality and allow the community to meet current
government disinfection regulations. The plan also accounts for community growth, allowing the system
to be used for at least the next 20 years.
The Problem
The problem was presented to the ACE Team as the complete redesign of a water distribution system along
with chlorine disinfection. Upon visiting the community in January, the team learned that a water
distribution system is in place but does not fully function. The team then turned its focus to analyze the
current system, identifying a number of problems.
First, areas of the community located at higher elevations do not receive proper pressures at their taps due
to lack of reservoir storage. Second, if the community is to grow in the years to come, pipe sizes must be
increased to handle larger volumes of flow.
Finally, due to recent changes in drinking water regulations in Ecuador, the community is required to
disinfect its water through chlorination. While chlorine disinfection was originally part of the community’s
system, application of the disinfectant was quickly stopped as the method was found to be tedious and more
of a hassle than a benefit.
The Solution
The team began the solving process by trying to understand the current system and its deficiencies. Using
the modeling software EPANET along with survey data collected while on a trip to Apatug, the ACE Team
was able to replicate in the model the problems that the community members were experiencing. These
problems are shown in Figure 1, where yellow denotes connections of negative pressure while red shows
areas of low pressure during tank-filling.
Figure 1. System Map Displaying Problem Areas
To address these problems, the team increased the water storage in the system at seven locations, adding
two reservoirs with a nominal volume of 5 cubic meters (m3), one of 10 m3, one of 25 m3, and three of 40
m3. This eliminated the pressure problem that some had seen when the community lacked storage. The team
also suggested increasing the size of around 2600 meters (m) of piping. This fix will allow future growth
and provides a much cheaper option than replacing the entire system. Third, valves will be installed to
regulate flow in the pipes, to manage water levels in the storage tanks, and to allow the reservoirs to be
taken off-line in case they need to be maintained or cleaned. Finally, water meters will be placed at all
homes so usage can be monitored and families properly charged for their water consumption. These
improvements are shown in Figure 2.
For the development of the chlorine pilot study, the team, at the suggestion of its client, decided to test two
non-electric fluid-driven pumps within a bench study. In this study, the team tested the pumps' precision in
dosing a chemical as well as the head required to drive the pump and apply the chemical to the water
flowing through.
Using the results of the bench study, the team decided to recommend a Dosmatic® SuperDos 20, which
would be best suited for the chlorine application. The team also determined that presenting this information
in the context of a pilot study was the best idea because these pumps have not been used in this type of
application.
The objectives of the pilot study are to implement and install the chlorine dosing system, complete with a
dosing pump, chlorine storage, and a shunt flow. The team recommends liquid 1% sodium hypochlorite to
be used for chlorination, with a dose of 1.5 milligrams per liter (mg/L) total chlorine. The existing reservoir
and pipe network provides a contact time of 40 minutes before the chlorinated water reaches the first house.
To increase contact time, the team recommends a baffle be installed to achieve a total contact time of 87
minutes. The free chlorine residual concentration in the system is desired to be 0.3 mg/L.
The pilot study will require members of the community to monitor chlorine residuals at ten locations
throughout the community to confirm that free chlorine residual is present but does not affect taste, while
also testing the water for coliforms to ensure adequate disinfection.
Figure 2. System Map Displaying Major Improvements
Implementation
The solution will be implemented over a number of years, minimizing effects on the current system while
addressing the most pressing needs first. The breakdown is as follows.
Year One
1. Increase size of the 2 pressure breaking tanks at the bottom of the community (Tanks 5 and 6) to mitigate
negative pressures as Tanks 4 and 5 refill
2. Move Side Tank connection into main network to where diameter changes from 90 mm to 75 mm
between the reservoir and Tank 1
3. Increase the pipe size of the southeast most branch from 20 mm to 50 mm
4. Install chlorine dosing pump and flow meters and purchase sodium hypochlorite
5. Begin implementation of pilot study
6. Protect exposed pipe between Splitting Tank and Main Reservoir
Year Two
1. Increase size of next 2 upstream pressure breaking tanks (Tanks 3 and 4) to mitigate low pressures
2. Increase pipe size of most southerly branch off of Tank 6 from 20 mm to 40 mm
3. Increase pipe size off of the Side Tank from 20 mm to 40 mm
4. Investigate use of electrolysis for sodium hypochlorite production
5. Install water meters
6. Continue to monitor chlorine residual
Year Three
1. Construct remaining 3 storage tanks (Tanks 1 and 2 and Side Tank)
2. Increase pipe size of loop between Tanks 4 and 5 from 40 mm to 90 mm
3. Increase pipe size of easterly most pipe branch from 20 mm to 32 mm
4. Add 50 mm pipe loop in the upstream part of community between Tanks 2 and 3
5. Consider installation of baffling in uppermost reservoir to improve CT tank efficiency
6. Continue to monitor chlorine residuals and water demand
Cost Estimate
The cost of the project will be about $175,000. Increasing the size of the tanks will cost $112,775 based on
a unit cost of $400/m3. Valves at all seven of the new tanks will cost about $12,460. Increasing pipe
diameters will then cost about $14,114. Installing meters will be another major cost, especially because
there are no homes that currently have them. Installation of 520 meters will run about $33,150. Costs for
the pilot study will be minor in comparison, with the largest cost being the purchasing of a pump and valves.
The pilot study cost will be about $2,163. While we can calculate a cost value for the project, it is unknown
what the community will have to pay for these improvements. The Ecuadorian government offers aid to
communities for infrastructure improvements, but does so sporadically. The community has reserve funds
for system improvements and maintenance as well.
Conclusion
The ACE Team believes that the multi-year improvement plan and chlorination pilot study will improve
the quality of life of those living in Apatug. Not only will water be fairly distributed and readily available,
but it will also be of a higher quality. The team has been blessed to work with the community of Apatug,
and is grateful to client Bruce Rydbeck for this opportunity.
TableofContents
Executive Summary
Table of Contents ........................................................................................................................................... i Table of Figures ........................................................................................................................................... iv Table of Tables ............................................................................................................................................. v 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 Project Location ........................................................................................................................... 3 1.2.3 Current Water Situation ............................................................................................................... 6 1.2.4 Project Client ............................................................................................................................... 7 1.3 Project Proposal .................................................................................................................................. 7 1.3.1 Purpose and Objectives ................................................................................................................ 7 1.3.2 Design Constraints ....................................................................................................................... 8 1.3.3 Design Criteria ............................................................................................................................. 9 1.3.4 Project Approach ....................................................................................................................... 10 1.4 Project Management ......................................................................................................................... 10 1.4.1 Team Organization..................................................................................................................... 10 1.4.2 Schedule ..................................................................................................................................... 11 1.4.3 Budget ........................................................................................................................................ 12 1.5 Design Norms ................................................................................................................................... 12 1.5.1 Cultural Appropriateness ........................................................................................................... 12 1.5.2 Transparency .............................................................................................................................. 13 1.5.3 Justice ......................................................................................................................................... 13 2. TRIP TO ECUADOR ............................................................................................................................. 14 2.1 Scope Changes .................................................................................................................................. 14 2.2 Similar Case Studies ......................................................................................................................... 16 2.3 Water Testing Results ....................................................................................................................... 17 i
2.3.1 Procedure ................................................................................................................................... 17 2.3.2 Results ........................................................................................................................................ 17 2.3.3 Water Testing Conclusions ........................................................................................................ 18 3. EXISTING SYSTEM ANALYSIS ......................................................................................................... 19 3.1 System Map ...................................................................................................................................... 19 3.2 EPANET Model ................................................................................................................................ 19 3.2.1 Assumptions ............................................................................................................................... 19 3.2.2 Procedure ................................................................................................................................... 20 3.3.3 Results ........................................................................................................................................ 20 3.4.4WaterTestinginEPANET ........................................................................................................ 24 4. CHLORINATION BENCH STUDY...................................................................................................... 27 4.1 Head Test .......................................................................................................................................... 27 4.1.1 Procedure ................................................................................................................................... 27 4.1.2 Results ........................................................................................................................................ 27 4.2 Dosing Test with Ion Chromatography (IC) Analysis ...................................................................... 28 4.2.1 Procedure ................................................................................................................................... 28 4.2.2 Ion Chromatography .................................................................................................................. 29 4.2.3 Results ........................................................................................................................................ 29 4.3 Dosing Test for Mixing ..................................................................................................................... 31 4.3.1 Procedure ................................................................................................................................... 31 4.3.2 Results ........................................................................................................................................ 31 4.4 Bench Study Conclusion ................................................................................................................... 31 5. FINAL DESIGN ..................................................................................................................................... 32 5.1 Three-Year Recommendation Plan ................................................................................................... 32 Year One ............................................................................................................................................. 32 Year Two ............................................................................................................................................ 33 Year Three .......................................................................................................................................... 34 5.2 Distribution ....................................................................................................................................... 35 5.2.1 Revised EPANET ...................................................................................................................... 35 5.2.2 Revised System Map .................................................................................................................. 37 5.2.3 Tank Design ............................................................................................................................... 37 5.2.4 Comparison to Church’s Method ............................................................................................... 39 5.2.5 Proposed Meters......................................................................................................................... 39 ii
5.3 Chlorination ...................................................................................................................................... 39 5.3.1 Chlorine Source and Storage...................................................................................................... 39 5.3.2 Chlorine Dosing ......................................................................................................................... 41 5.3.3 Chlorine Residual and Bacteriological Monitoring ................................................................... 46 5.3.4 Chlorination Pilot Study ............................................................................................................ 47 5.4 Costing .............................................................................................................................................. 52 5.4.1 Distribution System Improvements Cost ................................................................................... 52 5.4.2 Chlorination Dosing System Cost .............................................................................................. 52 5.4.3 Community Rate ........................................................................................................................ 53 5.5 Maintenance ...................................................................................................................................... 53 5.6 Sustainability..................................................................................................................................... 53 5.7 Conclusion ........................................................................................................................................ 54 6. ACKNOWLEDGEMENTS .................................................................................................................... 56 7. REFERENCES ....................................................................................................................................... 57 iii
TableofFigures
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 shown using Google Maps [2] ....................................................... 4 Figure 3. Terrain Map of Apatug, Ecuador from Google Earth [2] .............................................................. 5 Figure 4. Protected Spring Collector Details, Plan View [5] ........................................................................ 6 Figure 5. Protected Spring Collector Details, Section View [5] ................................................................... 7 Figure 6. Project Roles by Team Member .................................................................................................. 11 Figure 7. Piping that Connects Houses to the Distribution System ............................................................ 15 Figure 8. Apatug Average Day Diurnal Flow Curve .................................................................................. 20 Figure 9. System Model with Pressure Breaking Tank (PBT) Labels ........................................................ 21 Figure 10. System Map Showing Location of Nodes of Interest ................................................................ 23 Figure 11. System/Household Pressures as Tanks 4 and 5 Refill ............................................................... 24 Figure 12. Water Age at Extreme Nodes .................................................................................................... 25 Figure 13. Water Chlorine Content at Extreme Nodes ............................................................................... 26 Figure 14. Pump Piezometer Set-Up........................................................................................................... 27 Figure 15. Pump Set-up with Faucet Intake on Right, Effluent on Left, and Dosing Solution on Bottom 29 Figure 16. Variability of Chloride Concentration at Varying Flow Rates .................................................. 31 Figure 17. System Map Displaying Major Improvements .......................................................................... 32 Figure 18. Lowest Pressures as Tanks 4 and 5 Refill, with Increased Tank 5 and 6 Size .......................... 33 Figure 19. Lowest Pressures as Tanks 4 and 5 Refill, with Increased Tanks 3-6 Size ............................... 34 Figure 20. Pressure Values at 13:30 Hours under Maximum Day Demands in 20 Years .......................... 36 Figure 21. Tank Design Front View (Scale 1:40) (Used with permission by Bruce Rydbeck) [12] .......... 38 Figure 22. Tank Design Top View (Scale 1:40) (Used with permission by Bruce Rydbeck) [12] ............ 38 Figure 23. Plastic 500 L Drum for Sodium Hypochlorite Storage [14] ...................................................... 40 Figure 24. Electrolysis Equipment Located in Santiago de Quito .............................................................. 41 Figure 25. The Existing Chlorination Building by the Existing Reservoir ................................................. 42 Figure 26. Schematic of the Existing Chlorination Building Layout in Apatug ......................................... 43 Figure 27. Proposed Chlorination Building with Pump Connection and Baffling Structure ...................... 44 Figure 28. Proposed Test Sites (Sitios) for Chlorine Residual and Bacteriological Monitoring ................ 50 Figure 29. Pilot Study Timeline Summary ................................................................................................. 51 iv
TableofTables
Table 1. Total Cost for Bench Study........................................................................................................... 12 Table 2. Water Chemistry Results from Testing in Apatug ........................................................................ 17 Table 3. Head Test Results ......................................................................................................................... 28 Table 4. IC Results for Dosmatic® ............................................................................................................. 30 Table 5. IC Results for MixRite .................................................................................................................. 30 Table 6. Design Headloss Coefficients, Allowed Maximum Flow ............................................................ 35 Table 7. Tank Design Sizes ........................................................................................................................ 37 Table 8. Church's Method typically used for design of rural water systems in Ecuador [13] .................... 39 Table 9. Summary of Chlorination System Components for Pilot Study ................................................... 48 Table 10. Recommended Testing Kits for Monitoring Chlorine Residual and Bacteriological Growth .... 48 Table 11. Overall Costs of Proposed Changes ............................................................................................ 52 Table 12. Increased Water Storage Costs ................................................................................................... 52 Table 13. Pilot Study Cost Breakdown ....................................................................................................... 53 v
1.INTRODUCTION
1.1SeniorDesignBackground
1.1.1CalvinEngineeringProgram
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, Ethiopia, 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]
1.1.2SeniorDesignClass
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
design and 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.
1.1.3TeamMembers
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 community.
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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)
MarkDeHaan
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. After
graduation, Mark will begin working at Prein&Newhof in Grand Rapids.
JeremyKamp
Jeremy Kamp is from Orland Park, Illinois. He has many interests in the field, but is particularly interested
in water resources and hydraulics. When he isn’t hitting the books hard, Jeremy enjoys playing baseball,
volleyball, basketball, and golf. Besides his interest in sports, Jeremy loves spending time in the outdoors
fishing and hunting with his family. Jeremy has accepted a civil engineering position with Prein&Newhof
in Grand Rapids upon graduation in May 2015.
NathanLaframboise
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. Nathan has accepted a position with GreenTech Engineering,
Inc. in Wixom, Michigan after graduation. 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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JulieSwierenga
Julie Swierenga is most recently from Greensboro, North Carolina. Through research, studying abroad, and
an internship, she has had many opportunities to work with water resources, distribution, and treatment.
Julie particularly enjoys working with Geographic Information Systems (GIS) to address water issues
through mapping. She has accepted a position with Prein&Newhof in Grand Rapids where she will work
with GIS and hydraulic modeling.
WendyTabler
Wendy Tabler is from Milwaukee, Wisconsin. Wendy is most interested in structural engineering, and is
especially interested in the connection between structures and water as it pertains to bridges. 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. After graduating from Calvin, Wendy
plans to attend graduate school at Vanderbilt University to continue her education in structural engineering.
1.2ProjectBackground
1.2.1ProjectSummary
Team 19, also known as the ACE (Agua y Cloración en Ecuador) Team, analyzed and assessed the current
water distribution system, suggested a multi-year improvement plan, and designed a chlorine disinfection
dosing plan in the form of a pilot study for the community of Apatug, Ecuador.
1.2.2ProjectLocation
Apatug is a community of 520 homes located in rural Ecuador, as shown in Figure 2 and Figure 3. The
community’s current water source is a protected mountain spring shared between five communities.
Because of its location in the Andes Mountains, the difference in elevation between the source spring and
the homes in Apatug is significant. Apatug is about 20 kilometers (km) southwest of Ambato, which is
Ecuador’s 10th largest city.
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N
100 km
Figure 2. Location of Apatug, Ecuador shown using Google Maps [2]
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Figure 3. Terrain Map of Apatug, Ecuador from Google Earth [2]
1.2.3CurrentWaterSituation
Apatug currently receives its water from a protected spring which is shared with four other communities
and serves a total of 1700 homes. A 110 millimeter (mm) diameter polyvinyl chloride (PVC) feed line runs
7 km from the springs at 4360 meters (m) elevation to deliver water to the communities, producing a total
volumetric flow of 28 liters/second (L/s). [3] 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 and a distribution
network which has a number of flaws. [4]
In Apatug, and in the case of many rural Ecuadorian communities, water is gathered from mountain springs
and piped to the community. 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 out, both wild and domestic, and prevent contaminated surface water
from tainting the spring water, as pictured in Figures 4 and 5.
Figure 4. Protected Spring Collector Details, Plan View [5]
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Figure 5. Protected Spring Collector Details, Section View [5]
1.2.4ProjectClient
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.
1.3ProjectProposal
1.3.1PurposeandObjectives
1.3.1.1Distribution
The purpose of designing water disinfection and improving the current distribution system for Apatug,
Ecuador, was to supply its 520 households with clean water under manageable pressures. Currently, small
reservoirs scattered throughout the community do not provide proper system storage, robbing community
members at higher elevations of water and creating negative pressures in the distribution system. 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.” [6] This right is further defined as
“entitling everyone to sufficient, safe, acceptable, physically accessible and affordable water for personal
and domestic uses.” [6] In July 2010, the United Nations (UN) General Assembly explicitly recognized this
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right through Resolution 64/292. [7] 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. [8] This distribution system works toward this Development Goal of providing the community
members of Apatug with 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. [4] The
reservoirs had to 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 had to be in the range of 20 m to 60 m of water, or if need be
10 m to 70 m, which would be admissible because Apatug is a mountainous community. The main objective
for the distribution system was to provide a multi-year improvement plan to be submitted to community
leaders, allowing Apatug to begin construction of the reservoirs and improving the system through other
means.
1.3.1.2Chlorination
The purpose of the chlorination design was to kill pathogens that can grow on the inside of pipes, walls of
storage tanks, and water mains throughout the distribution system. Disinfection renders the water safe for
human consumption. Currently, water is collected from a protected spring on Mt. Carihuairazo and
transported to the community of Apatug, Ecuador, via a 7 km 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. [9] 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 was to administer chlorine to the distribution system according to
Ecuadorian regulations. Further specifications were set forward by our client Bruce Rydbeck. [10] Chlorine
was to be introduced into the system using non-electric fluid-driven injector pumps. These pumps had to
be adjustable so the dosing rate could be responsive to changes in flow during times of high demand and
during times of low demand. The pumps had to dose the water from the spring to a range of 0.5 to 2 parts
per million (ppm). Chlorine that could be acquiesced within Ecuador was the best option, which includes
liquid sodium hypochlorite, or diluted household bleach. It was critical that an adequate chlorine residual
concentration be maintained throughout the distribution system to prevent pathogenic growth.
1.3.2DesignConstraints
There were a number of aspects of the design process that constrained how the final product was developed.
The first constraint was 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 light, which do not leave a residual disinfectant in the distribution
system.
Material availability in Ecuador also limited the design of the Apatug distribution system. To design a
system which was culturally appropriate, materials such as ductile iron were quickly ruled out of the design
process due to their lack of availability. Additionally, in order to be culturally appropriate, material cost
had to be considered.
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Another important constraint in improving the distribution system was the change in elevation in the
community. These elevation differences required the strategic placement of reservoirs to create pressure
zones to keep pressures from being too high in various parts of the community. This large elevation range
constrained how much of the community could be regulated by a single pressure district and dictated the
number of pressure districts that were necessary. The village consists of 520 homes, and all of these homes
had to be served by the 6 L/s flowing from the spring while maintaining adequate pressures.
Along with the establishment of pressure districts, the design specifications of the storage tanks were based
on per capita daily consumption of water and the number of residents within a given pressure district.
All of these factors were taken into careful consideration when considering improvements for the
distribution system. Inability or unwillingness to do so could have resulted in a faulty product or system
which could easily fall into disrepair.
1.3.3DesignCriteria
In order to design a chlorine dosing system, design decisions needed be made that fulfilled the goal of the
project while considering the design norms of cultural appropriateness, justice, and sustainability. Decision
matrices were developed and used to determine the most appropriate disinfection material and delivery
method for the community of Apatug.
1.3.3.1DisinfectionMethod
The following criteria were considered in determining the disinfection methods and were used to weigh
alternatives as shown in a Decision Matrix found in Appendix A:
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 conditions of pH = 8, 75oF water with no turbidity or natural organic matter (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 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?
1.3.3.2DisinfectionDosing
The following criteria were considered in determining the disinfection dosing methods and were used to
weigh alternatives as shown in a second Decision Matrix found in Appendix A:
1.
2.
3.
4.
Liquid Inject – Can the chlorinator handle liquid sodium hypochlorite?
Adjustable Feed Rate – Is the feed rate self-regulating?
Dependability – Is the method rugged enough for prolonged use without maintenance?
Ease of Construction – Are special expertise needed to set the system up properly?
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1.3.4ProjectApproach
The ACE Team 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 was aware that the assistance of more experienced and knowledgeable mentors was essential
to the success of the project. The team used the resources of professors, an industrial consultant, and the
project client to ask questions and seek information. A humble posture allowed the team to be open to
suggestions and new alternatives that had not been initially considered. Humility put 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 to have partnered with Bruce Rydbeck and the community of Apatug to
utilize time and resources to develop an improvement plan and design a 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 were used to benefit the
people of Apatug. The team is also grateful to have had the opportunity to be hosted by the community in
January.
Finally, the ACE Team was 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 had the potential to
provide clean water to the residents of Apatug for years to come. This knowledge reinforced the importance
of design norms in the implementation of the project, particularly those of justice, cultural appropriateness,
and sustainability.
This project was 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 was tested using EPANET, a free water distribution network analysis software developed and
distributed by the Environmental Protection Agency (EPA). The results were discussed with the client
before a final recommendation was made. Similarly, the chlorination system was design upon a foundation
of research, and a bench scale study was used to test the effectiveness of the chosen system. It was important
that each aspect of the design be tested and evaluated before a final design was recommended.
1.4ProjectManagement
1.4.1TeamOrganization
The ACE Team assigned team roles to facilitate project management and implementation. Individual team
members were responsible for research activities, as well as tracking hours. All of the team members also
contributed to report writing.
Wendy Tabler was responsible for team management, ensuring that all tasks were completed in a timely
manner. She also played a lead role in developing the computer model for the water distribution system.
Jeremy Kamp’s primary role was leading the AutoCAD drafting and drawings. Jeremy also contributed to
the business plan, cost estimation components of the project, and model development. Mark De Haan was
in charge of the budget for the team. He was also responsible for the completion of the business plan,
contributed to chlorine pilot study and bench study development, and played a lead role in the preliminary
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model development. Mark also wrote all of the team’s weekly memorandums and drafted team reports.
Nathan Laframboise organized the research efforts of the team and the bench study preparation. He also
took the lead in communicating with pump suppliers for bench study materials and contributed to chlorine
pilot study development. Julie Swierenga was in charge of managing the survey data using GIS (Geographic
Information Systems), the chlorination pilot study, and the team’s web communications (website, with the
client, etc.). She was also responsible for chlorine dosing calculations and design considerations and
contributed to bench study preparation. Figure 6 shows a graphic representation of team roles and
responsibilities.
Wendy Tabler
Jeremy Kamp
Mark De Haan
Nathan Laframboise
Julie Swierenga
LEAD Hydraulic Modeling
AutoCAD Drafting
Business Development and Reporting
Chlorination Bench Study
Chlorination System Design and Mapping
Hydraulic Modeling and Business
Hydraulic Modeling and Chlorination
Chlorination System Design
Chlorination Bench Study
Report Writing and Drafting
Report Writing and Budgeting
Research and Materials Acquisition
Website and Client Communication
SUPPORT Reporting and Communication
ADMINISTRATION Team Management
Figure 6. Project Roles by Team Member
1.4.2Schedule
The two semesters of the senior design course were split into two main focuses for the ACE Team. The
first semester was spent mainly on developing the initial water distribution system computer model while
also looking at the feasibility of the project. Second semester focused on the analysis of the current
distribution system, improvements for the distribution system, the design of the chlorination system, and
the method through which the chlorine is be administered to the distribution system. In January, four
members of the ACE Team traveled to Ecuador to visit the community and performed water chemical
analysis, quality tests, and a topographic survey in Apatug. The four members also visited similar
distribution systems that are currently in operation. The complete schedule of the trip is outlined in
Appendix B.
The team loosely followed a Gaant Chart each semester, given in Appendix C, especially at the beginning
of each semester, to keep them on track and aware of remaining tasks to accomplish. On a weekly basis,
the ACE Team gathered to share progress and results. They also periodically had meetings with their project
advisor to discuss progress and address questions. On a regular basis, the team determined a plan of action
11
for the necessary tasks each member should accomplish. The broad tasks and goals for each semester were
kept on one whiteboard next to the team’s station, and the individual current tasks were kept on the other
whiteboard with assignments for each team member. Each team member tracked hours spent on the project
using a spreadsheet located on a shared Google Drive, which averaged out to about 8 hours per week per
team member. Since the project had two major components: the water distribution system and the chlorine
dosing system, team members met in smaller groups more frequently throughout the week.
1.4.3Budget
The ACE Team was provided with a budget of $500 by the Calvin College Engineering Department. This
money went toward the bench scale study and the purchasing of two non-electric fluid-driven injector
pumps. These pumps have been tested against each other to see if they perform as expected. Table 1 shows
a summary of the total cost for the bench study.
Table 1. Total Cost for Bench Study
Item
MixRite Pump
Dosmatic Pump
Pump Fitting and Bench Study Supplies
Total
$
$
$
$
Cost
376.54
269.00
45.64
691.18
The cost of the bench study, $691.18, was over the original budget of $500 because a second pump was
purchased for the bench study. The team applied for this cost to be covered through the Eric DeGroot
Engineering Fund Scholarship, and that was granted. We are very grateful to the DeGroot family for their
contributions to our project.
When making design decisions about materials and methods to use in the distribution and chlorination
system in Apatug, the ACE Team did 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 chlorination
system. The ACE Team used the provided senior design budget for bench study materials, but trip funding
was funded by individual team members, and the distribution system improvements and chlorination will
be funded by the community and Ecuadorian government.
1.5DesignNorms
Design norms provided a framework through which the project was completed. These design norms insured
that the project was done with the correct mindset and that the ethical guidelines, which are an important
aspect of the engineering profession, were considered in the areas of technical design and ethical
constraints.
1.5.1CulturalAppropriateness
When working on a project in a foreign country, designing with cultural appropriateness in mind is
paramount. In a community that had a chlorine disinfection system that fell out of working order, it was
important to design the dosing system so that this would not reoccur. The team also wanted to design using
materials that are readily available in the situation that maintenance or repair is necessary. Additionally, the
12
materials that are readily available in the situation that maintenance or repair is necessary. Additionally, the
chlorination should be carefully regulated so that it has a minimum effect on taste. Cultural appropriateness
also takes into account non-technical aspects of the design such as the tank locations being limited to areas
owned by the local water board. In order for the system to be embraced, it must work in conjunction with
the culture of Apatug.
1.5.2Transparency
To design a system which will work correctly and be reliable for years to come, transparency was important
for all aspects of the design process. The team had to be upfront with the client, advisor, and industrial
consultant so that any problems the team faced were solved correctly and efficiently. Any questions had to
be communicated clearly to ensure understanding between team and consultant while any potential cultural
issues had to be discussed with the community. While learning was an important aspect of the senior design
course, the team was also asked to produce a final product, which was to be designed as efficient and
reliable. For this reason, communication between the team and its consultants had to be transparent, so all
aspects of the project were correctly addressed.
1.5.3Justice
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 focused 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.
13
2.TRIPTOECUADOR
Four members of the ACE Team made trips to Ecuador at the end of January. Julie and Wendy arrived in
Quito on January 19 while Mark and Nathan followed on January 23. The team members spent time in the
project community of Apatug to collect data and perform water testing. The team also visited four other
communities with functional water systems to evaluate the performance of each and to compare to the
system being designed for Apatug.
Apatug
The women of the team spent four days in Apatug before the remaining two team members arrived. Upon
arrival in Apatug, Julie and Wendy learned that the current water distribution system works and is providing
water to the community despite the previous report the complete system had collapsed.
With this new and integral information in mind, Julie and Wendy questioned the people of the community
about the system. Many were happy with the system, although the uppermost pressure zones were lacking
sufficient water pressure due to the draw of water to the lower portion of the community. Julie and Wendy
also obtained a hand-drawn diagram of the current water system to better understand the layout of the
distribution pipes. Julie and Wendy then collected survey data for a few days before returning to Quito on
Friday.
Mark and Nathan joined the two other team members in Ecuador, and on Monday, the four returned to
Apatug to collect the remaining data necessary to complete a hydraulic model of the current system. The
team also inspected the community’s reservoir and pressure breaking tanks. Using a rough method of
measuring flow rate, the team determined that Apatug received about 6.1 L/s of flow. The team also
performed water testing, determining that the water from the tap in Apatug had a pH of 7.5-8, no measurable
nitrite or ammonia, and an average total hardness of 77.8 mg/L.
After staying in the community for two-and-a-half days, the team traveled to Riobamba and the surrounding
area to visit four other communities with functional water systems for comparison and evaluation purposes.
2.1ScopeChanges
At the writing of the Project Proposal and Feasibility Study for the project, the team understood the scope
of the project as designing a complete water distribution system for the community of Apatug, assuming
that there was no system currently in place. However, after traveling to Apatug and learning that there was
an existing distribution system already providing drinking water to the majority of homes, the community,
the client, and the team altered the scope of the project. Figure 7 shows one of the house connections in the
distribution system.
14
Figure 7. Piping that Connects Houses to the Distribution System
The most significant change in scope concerned the water distribution system. Since the existing system,
which mainly consists of PVC pipe and has been in place for twenty-five years, is mostly functional, the
team did not recommend that a new distribution system replace the existing system. Instead, the team
addressed concerns voiced by the community about the existing distribution system and developed a multiyear recommendation plan for water distribution system improvements. This recommendation plan
prioritized changes that should be made to the distribution system, taking into account cost-effectiveness
and the development of momentum in implementing the changes.
The concerns brought to the attention of the team by the community leaders include a lack of sufficient
water storage to supply water to all of the homes during times of peak water use. Currently, homes located
above the main stadium area, where Tank 5 is located, are not able to sustain significant water pressures at
high demands. To address this issue, the team created a hydraulic model of the current system to recreate
the pressure issues. Then, the team proposed the construction of larger storage tanks in place of the pressure
breaking tanks currently employed in Apatug, using another hydraulic model for the recommended system.
The hydraulic model was useful in prioritizing new tank construction. Part of the team’s recommendation
also included a procedure for new tank construction while ensuring that existing water service is not
interrupted.
Another scope change concerns the design of the chlorination system for Apatug. After visiting the
community and talking with the client, the team decided that it would be more beneficial to the community
to design a chlorination pilot study using Apatug’s water distribution system. This change meant that
instead of presenting plans for chlorine dosing and implementation, the team presented the chlorination
system as part of a community-wide study of using fluid-driven chemical injection pumps to dose a water
distribution system. By designing the system through the lens of a pilot study, both the team and the
community are able to approach chlorine disinfection with a posture of learning and experimentation. The
pilot study will fully involve the community in their own chlorination system, giving ownership and control
of the system to Apatug. The study could also have additional benefits, including more data and experience
15
with using the dosing pumps, a better knowledge of the quality of the drinking water, a better understanding
of the contact times achieved in the system, and what is necessary for a chlorination system to gain
acceptance and be sustainable in a rural Ecuadorian community. By providing Apatug with the tools and
design necessary to implement the pilot study, it is hoped that Apatug could be an example for surrounding
communities in developing a sustainable chlorination system.
2.2SimilarCaseStudies
Achullay
The first community visited was Achullay. This community had just completed its water system in the
months before, and the team was fortunate enough to take part in a water celebration service with the
members of the community.
One of the main differences between Achullay’s water system and Apatug’s is that the designed water
system for Apatug is completely gravity-driven, as water comes from a mountain spring at a higher
elevation and flows downhill to the community. At Achullay, the spring is at a lower elevation and water
is pumped to a reservoir at the highest part of the community. However, Achullay did have a reservoir at
the top of the hill that was an example crucial to the team’s design.
LopaxiChico
Much like Achullay, the water system at Lopaxi Chico collects water from a spring at the base of a hill and
pumps the water to the top. Lopaxi Chico is a community which contains 62 homes. At Lopaxi Chico, the
team ran into the problem of broken float valves which have resulted in the pumps being turned on and off
manually rather than automatically, as originally designed. The team also noticed the wasted space in the
reservoir due to the height of the overflow pipe. Those living in Lopaxi Chico are being charged $0.50 per
cubic meter (m3) of water used.
LopaxiGrande
Lopaxi Grande is a community of 106 households that is served by 0.6 L/s, a much lower volume amount
per household than the 6.1 L/s which serve the 520 households of Apatug. Lopaxi Grande also pumps water
from a lower spring to a higher reservoir, and uses two 3-horsepower pumps to do so. The system has been
working automatically with a float valve for seven years; it is very rare to see an automatic system work
without the float valve breaking down after two or three years, let alone seven. Like Lopaxi Chico, Lopaxi
Grande charges $0.50 per cubic meter of water used, but collects a minimum of $1.00 per month from each
household. One unique feature of the system at Lopaxi Grande is that the pumps are located outside of the
pump house in a deep clear well. The pumps were relocated because the pump house was at too low of an
elevation and flooding was an issue, with flood waters running into the existing clear well.
Yanacocha
The final community visited was Yanacocha, a community of 66 households that was served by a flow of
0.6 L/s. Again, water was pumped from a low spring to a high reservoir. The system is only two years old,
but like Lopaxi Chico, the pumps have to be turned on and off manually because of a broken float valve in
the uppermost reservoir. The pump is turned on for a 24-hour period once every three days to fill the
reservoir. The community members are charged $0.75 per cubic meter of water. At Yanacocha, the team
was able to see the type of spigot that would be installed at Apatug – a concrete encased pipe that sits about
1 m off the ground and has a meter on top to track water use.
16
All four community visits outside of Apatug gave the team a better understanding for what a water system
improvement plan would entail. The visits also allowed the team to be appreciative of the work that client
Bruce Rydbeck has done, and the ways that quality of life improves for community members from running
water.
2.3WaterTestingResults
2.3.1Procedure
A Hach Nine-Parameter Test Kit was used for all water chemistry tests, including temperature and pH. A
copy of the product sheet from Hach is included in Appendix D. The tests were carried out according to the
included instruction manuals, and were primarily based on color change. The tests were implemented on
the water in Apatug a total of two times on two different days, with one test in the morning and one in the
evening. The results of the test were recorded and compared to a sample of purified water from Quito.
2.3.2Results
2.3.2.1WaterChemistry
Results from the water chemistry tests performed in Apatug are presented in Table 2. The turbidity of the
water in Apatug was also observed and determined to be effectively zero. A Secchi disk apparatus was used
to compare the turbidity of the Apatug water to purified water from Quito, and no difference was determined
between the water samples. The clarity of the water delivered to Apatug was further confirmed by observing
water in laundry basins throughout the community: from a rooftop, the tiles at the bottom of a laundry basin
were clearly visible through 1 m of Apatug water.
Table 2. Water Chemistry Results from Testing in Apatug
Apatug Water
Purified Water*
5:00 PM
(Jan 27, 2015)
53 °F (11.7 °C)
8
7:00 AM
(Jan 28, 2015)
52 °F (11.1 °C)
7.5
5:00 PM
(Jan 27, 2015)
60 °F (15.6 °C)
8
Ammonia
(mg/L NH3)
0
0
0
Nitrite
(mg/L NO2-)
0
0
0
Total Hardness
(mg/L CaCO3)
85.5
70
70
Chloride**
(mg/L Cl2)
< 30
< 30
< 30
Temperature
pH
*Filtered drinking water from Quito, Ecuador.
**30 mg/L Cl2 is the minimum concentration that can be measured using the Hach testing kit.
17
2.3.3WaterTestingConclusions
From the water testing performed in Apatug, the team concluded that the mountain spring supplying the
community is of high quality. The lowest recorded water temperature in the community of 52 °F and the
highest recorded pH of 8 were used in all chlorine dosing calculations as the most conservative values. The
low turbidity of the water in Apatug is a positive factor in the use of chlorine disinfection, as the production
of DBPs is a more serious concern in turbid waters. Due to the lack of evidence of biological contamination
in the water, it was assumed that the chlorine demand in the contact tank will be negligible, and that the
primary purpose of chlorination will be to maintain a residual disinfectant concentration throughout the
distribution system.
18
3.EXISTINGSYSTEMANALYSIS
3.1SystemMap
While the team was in Apatug over January, they obtained a hand-drawn map of the current system.
Although the Water Board attested to at one time having a written record of the pipe system, it had been
lost. This hand-drawn map was done by Lorenzo, who is the head technician of the community’s Water
Board. From memory and his work on the pipe network, he drew the map, complete with concurrent roads
and all pipe diameters. This drawing was then used to create the current system map in AutoCAD.
The one thing this drawing was lacking was specific pipe lengths, which were assumed based on images
from Google Earth. Using the road survey points, the Google Earth images were rotated and scaled by
matching intersections with their corresponding survey point. A scale for the map was created by using the
length between two survey points compared with the measurement of that distance in Google Earth.
Once the Google Earth images were situated correctly, the roads were traced over the images. The Google
Earth images helped to get the smaller roads and walking paths on the hand drawing that did not have
survey points associated with them. After the roads were correctly laid down, the pipes were drawn in place.
The tanks were drawn from the Global Positioning System (GPS) points taken on site. The pipes were then
connected to match the hand-drawing. Home survey points were also brought into the drawing to more
accurately locate some of the pipe locations that did not follow the roads.
After the map was completed it was sent to Bruce Rydbeck in Ecuador so that the community could do a
field check and make sure that it most accurately represented the current system. There were no changes
brought forward by the community.
3.2EPANETModel
The hand-drawn pipe network, the house points from the topographic survey, and Google Earth images
were used together to create an EPANET model of the current system in order to analyze it and identify its
deficiencies.
3.2.1Assumptions
A number of assumptions were made in order to simplify the system for modeling purposes:
1. The average daily water demand of the community members is about 100 L/person/day.
2. Houses could be grouped together and assigned a common elevation.
3. Connections to houses did not need to be distinctly modeled, but could be taken as nodes with
demands on the main pipe system.
4. Every house location obtained in the survey is already connected to the pipe network.
5. Since only two of the seven pressure breaking tanks were shot in the topographic survey, the
elevations of each tank could be extracted from a contour surface of the survey data points.
6. There are breaks in the pipe loop between Tank 5 and Tank 6 in order to separate the pressure
zones. If there were not breaks, Tank 6 would never fill. Because the tank was filling upon
examination in January, this assumption must be valid.
7. The only type of valve present in the system is float valves in each pressure breaking tank.
8. One church or one school uses as much water daily as two households.
19
9. The diurnal pattern of the water demand on the system is similar to the published AWWA Standard,
but peaks at the lunch hour, around 1:00 pm, instead of in the morning, and at a later dinner hour,
around 8:00 pm [11]. The average day diurnal flow curve as modified and used in the system is
shown in Figure 8.
1.8
1.6
Peaking Factor
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0
4
8
12
16
20
24
Time (hours)
Figure 8. Apatug Average Day Diurnal Flow Curve
3.2.2Procedure
First, the survey points were brought into EPANET and grouped with 1-6 other house points. From the
drawn network map, pipes, pipe lengths, and pipe diameters were assigned with reference to Google Earth
Images, where relative distances were measured between parallel streets. The house groups were then
combined even further to groups of 1-26 total homes, based on location relative to the piping network and
similar elevations. If the group was nearer to the upper range of a pressure zone, the highest elevation of
the group was assigned to the grouped point. If the group was nearer to the bottom range, the lowest
elevation of the group was used. In either case, the more extreme value was used. Tanks were taken as 1.5
m3 in volume, with inner depth of 1 m and an equivalent diameter of 1.38 m. The demand pattern from
Figure 8 was applied to the system as the average daily flow, and multiplied by two and applied to the
system as the maximum daily flow.
3.3.3Results
The overall model is shown in Figure 9.
20
21
PBT SIDE
PBT 1
RESERVOIR
Upstream
Reservoir
Pressure Breaking Tank (PBT)
LEGEND
 House Group
Figure 9. System Model with Pressure Breaking Tank (PBT) Labels
PBT 2
PBT 3
PBT 4
PBT 5
Downstream
PBT 6
According to the model, the current system contains numerous deficiencies. First, the pressure breaking
tanks are too small to mitigate peak fluctuations and are too small to provide any sort of storage. The tanks
are constantly refilling (2-5 times per hour), and when tanks downstream fill at the same time, they cause
negative pressures at the upstream end of the system. The two nodes on the pipeline branching off from the
main line to connect with the side pressure breaking tank (see Figure 10) experience negative pressures at
4 times throughout the day and fluctuate between 65 m of pressure and 8 m of pressure for the rest of the
day.
22
23
Upstream
Nodes of
Interest
Reservoir
Figure 10. System Map Showing Location of Nodes of Interest
Pressure Breaking Tank (PBT)
LEGEND
 House Group
In the current system, the use of water downstream creates regions of low pressure upstream of Tank 5 in
the stadium, as is shown in Figure 11. This corroborates what the community told the team was the current
main issue in the system.
Figure 11. System/Household Pressures as Tanks 4 and 5 Refill
The system also allows surges of water through the pipes in order to fill the tanks, which creates unnecessary
pressure on the tanks. The final issue with the current system made clear by the model is that there is
significant room for growth in the community upstream that cannot be utilized without additional network
loops.
3.4.4WaterTestinginEPANET
EPANET has the capability to run various water quality tests which prove advantageous when seeking to
quantify how efficient the new distribution system might be. The first test is a water age test which predicts
the longest time water will sit in any part of the system. This test is necessary because, at a glance, it tells
the user whether the system is responding to demand as designed. Figure 12 shows water age for the furthest
nodes in the system with the independent axis in hours of time, and the dependent axis in hours of age.
24
What can be observed from this graph is the maximum amount of time water will remain in a particular
node is no longer than 38 hours.
Figure 12. Water Age at Extreme Nodes
The second test is a chlorine degradation test which indicates how much free chlorine will be available at a
particular time, given its position in the system. The importance of this test cannot be overstated because,
if chlorine degrades to a certain point, it will no longer be able to prevent bacterial growth in the system.
Chlorine degradation in EPANET works by inputting a global bulk coefficient of -1 and setting the initial
quality of the reservoir to the desired dose which, in this case, would be 0.3 mg/L. Figure 13 shows various
nodes and their concentrations over a 72 hour period.
25
Figure 13. Water Chlorine Content at Extreme Nodes
Something to notice is how an inverse relationship exists between the two graphs. Hour 52 for node 23
shows the Chlorine residual to be at its minimum while the water age at that point is a maximum. Hour 36
and hour 60 for node 58 show the same pattern; this is expected because chlorine concentration is a function
of time based upon first order kinetics.
26
4.CHLORINATIONBENCHSTUDY
4.1HeadTest
4.1.1Procedure
A bench study was performed to gather information about two fluid-driven injector pumps purchased by
the team: the MixRite injector and the Dosmatic® MiniDos injector. First, a head test was performed. For
this test, ¾-inch diameter PVC pipe was connected to each side of the pump. A clear tube was then
connected to the PVC pipe on either side of the pump by drilling a hole into the PVC. Figure 14 shows a
picture of the head piezometer set-up. The clear tubes allowed the headloss (Δh) over the pump to be
calculated by measuring the water level in the clear tubes and using the difference in the height to calculate
the headloss through the pump.
Flow
Figure 14. Pump Piezometer Set-Up
4.1.2Results
Since the pumps are fluid-driven injector pumps, the head difference varied greatly depending on whether
or not the pump was pulling in the dosing solution. This head variation made it difficult to measure the head
difference, so two different headlosses were calculated based on the highest and lowest water levels
27
measured in each piezometer. A low and high dosing ratio were used with the same flow rate in liters per
minute (L/min) in both pumps to see if the dosing ratio had any effect on the headloss.
Table 3 shows the results from the head test for both pumps.
Table 3. Head Test Results
Flow Rate
(L/min)
MixRite
1.32
1.32
Dosmatic®
1.32
1.32
Dosing Ratio
(%)
Low Head
Difference (m H2O)
High Head
Difference (m H2O)
0.30
2.00
43.6
58.0
62.6
90.0
0.30
1.00
100.6
107.0
129.2
128.0
4.2DosingTestwithIonChromatography(IC)Analysis
4.2.1Procedure
The first dosing test that was completed was intended to determine how much the dosing performance of
the pump varied with different flow rates at the same dosing ratio. The flow rates from the faucet, which
were controlled for each proceeding test, were measured by timing how long it took to fill up a known
volume in a bucket or a large graduated cylinder. Three different flow rates were tested at three different
dosing ratios. The three different flow rates were approximately 1.98 L/min, 6.25 L/min, and 17.51 L/min.
The tested dosing ratios for the MixRite were 0.30%, 1.0%, and 2.0% while the dosing ratios used for the
Dosmatic® pump were 0.20%, 0.60% and 1.0%.
A solution of 500 mg/L sodium chloride (NaCl) solution was prepared to use as the dosing solution. Both
pumps were run at the three different flow rates with the three different dosing ratios, and samples were
taken from the effluent of the pump. A sample of the tap water was taken right after each dosing ratio was
run to compare any variation of the NaCl content in the tap water to the dosed water. A sample of the dosing
solution was also prepared to determine how much chloride was being dosed by the pump. Figure 15 shows
the set-up of the Dosmatic® pump. The setup was the same for the MixRite pump, except the flow was in
the opposite direction through the MixRite pump.
28
Figure 15. Pump Set-up with Faucet Intake on Right, Effluent on Left, and Dosing Solution on Bottom
4.2.2IonChromatography
Once all the samples were collected, they were prepared for IC analysis. Each sample was filtered through
a syringe and put into plastic ion chromatography cartridges. The cartridges were placed in the IC machine
which took 15 minutes to analyze each sample for anion concentrations. The tap water sample concentration
was subtracted from the measured concentration in each of the pump samples, as the remaining chloride
concentration is assumed to be from the dose administered by the pumps. Using the tap water samples and
the dosing solution samples as baselines, the amount of chloride being dosed and the concentration
variability between samples at the same dosing ratio and varying flow rates could then be calculated. An
expected dose of sodium chloride was calculated for each sample based on the measured concentration of
the dosing solution and the dosing ratio, which was then compared to the IC results.
4.2.3Results
The results of the IC analysis are summarized in Table 4 for Dosmatic® and Table 5 for MixRite. Figure
16 shows a graph of the variability of the chloride concentrations for each pump. Each data point represents
a different flow rate, and they are grouped by dosing ratio. Both pumps respond as expected to varying flow
rates, keeping the chloride concentration in the effluent relatively constant. As part of the IC analysis,
standards were run for 5 mg/L and 10 mg/L, among others. The measured concentration by the IC for the
5 mg/L standard was 4.514 mg/L chloride, suggesting that the IC results may only be accurate to the nearest
0.5 mg/L. In addition, two samples of the dosing solution were tested using the IC, and although the samples
were collected in the same way from the same container, the measured concentrations varied by about 3
mg/L. For these reasons, the results of the IC analysis are valuable in showing that the pumps dose as
expected and respond relatively well to changes in flow rate, but further testing is required to determine the
29
true accuracy and precision of these pumps. A pilot study at a larger scale will be necessary to better
determine the effectiveness of these pumps as part of a chlorination system.
Table 4. IC Results for Dosmatic®
Sample
1
2
3
4
5
6
7
8
9
Dosing
Ratio
0.2%
0.2%
0.2%
0.6%
0.6%
0.6%
1.0%
1.0%
1.0%
Flow Rate
(L/min)
2
6
18
2
6
18
2
6
18
Expected
Chloride
Concentration
(mg/L)
0.66
0.66
0.66
1.98
1.98
1.98
3.28
3.28
3.28
Difference from
Expected
Concentration
(mg/L)
0.45
0.85
0.82
0.17
0.85
0.49
0.47
0.63
0.37
Variation of
Measured
Concentration
(mg/L)
Difference from
Expected
Concentration
(mg/L)
0.14
0.51
0.41
0.49
0.09
0.12
0.92
0.26
0.80
Variation of
Measured
Concentration
(mg/L)
0.40
0.69
0.26
Table 5. IC Results for MixRite
Sample
1
2
3
4
5
6
7
8
9
Dosing
Ratio
0.3%
0.3%
0.3%
1.0%
1.0%
1.0%
2.0%
2.0%
2.0%
Flow Rate
(L/min)
2
6
18
2
6
18
2
6
18
Expected
Chloride
Concentration
(mg/L)
0.99
0.99
0.99
3.28
3.28
3.28
6.50
6.50
6.50
30
0.92
0.34
0.67
7.0
Chloride Concentration (mg/L)
6.0
MixRite
Dosmatic
5.0
4.0
3.0
2.0
1.0
0.0
Low Dosing Ratio
Mid Dosing Ratio
High Dosing Ratio
Figure 16. Variability of Chloride Concentration at Varying Flow Rates
4.3DosingTestforMixing
4.3.1Procedure
A simple test was performed to visually confirm that the each pump was dosing a well-mixed dose of
chemical and not just a burst of chemical. In order to visually make sure that the pump was dosing as
desired, red food coloring was added to the 500 mg/L NaCl dosing solution.
4.3.2Results
The effluent from the pump showed that the water was well-mixed with the dosing solution since no burst
of red could be seen in the clear hose connected to the downstream end of the pump. However, the water
going back into the sink was light red in color, which means it was getting dosed properly and that proper
mixing was occurring within the pump itself.
4.4BenchStudyConclusion
According to the results of the first test, the headloss through each pump is highly variable, depending on
dosing ratio and flow through the pump. Both the MixRite and the Dosmatic® pumps responded well to
changes in flow rate, although further testing is needed to determine accurate doses and if the doses are
precise enough to be used effectively in a chlorine disinfection system. Both pumps exhibited good mixing
properties and were easy to operate and install. Based on the results of the bench study, the team
recommended that a pilot study be performed with the pumps to determine their ability to effectively
disinfect a large-scale distribution system.
31
5.FINALDESIGN
5.1Three‐YearRecommendationPlan
The three-year recommendation plan is summarized by Figure 17 and the final plan set for the community
can be found in Appendix E.
Figure 17. System Map Displaying Major Improvements
YearOne
1. Increase size of the 2 pressure-breaking tanks at the bottom of the community (Tanks 5 and 6) to mitigate
negative pressures as Tanks 4 and 5 refill as shown in Figure 18
32
Figure 18. Lowest Pressures as Tanks 4 and 5 Refill, with Increased Tank 5 and 6 Size
2. Move Side Tank connection into main network to where diameter changes from 90 mm to 75 mm
between the reservoir and Tank 1
3. Increase the pipe size of the southeast most branch from 20 mm to 50 mm
4. Install chlorine dosing pump and flow meters and purchase sodium hypochlorite
5. Begin implementation of pilot study
6. Protect exposed pipe between Splitting Tank and Main Reservoir
YearTwo
1. Increase size of next two upstream pressure breaking tanks (Tanks 3 and 4) to mitigate low pressures, as
shown in Figure 19
33
Figure 19. Lowest Pressures as Tanks 4 and 5 Refill, with Increased Tanks 3-6 Size
2. Increase pipe size of most southerly branch off of Tank 6 from 20 mm to 40 mm
3. Increase pipe off of the Side Tank from 20 mm to 40 mm
4. Investigate use of electrolysis for sodium hypochlorite production
5. Install water meters
6. Continue to monitor chlorine residual
YearThree
1. Construct remaining three storage tanks (Tanks 1 and 2 and Side Tank)
2. Increase pipe size of loop between Tanks 4 and 5 from 40 mm to 90 mm
3. Increase pipe size of easterly most pipe from 20 mm to 32 mm
4. Add 50 mm loop in the upstream part of community between Tanks 2 and 3
34
5. Consider installation of baffling in uppermost reservoir to improve tank efficiency
6. Continue to monitor chlorine residuals and water demand
5.2Distribution
5.2.1RevisedEPANET
A new model was created to simulate potential changes to the system in order to correct the issues identified
with the existing system. The new model has a design life of 20 years, using a 1.5% population growth rate.
Under the maximum day demands projected at 20 years, the pressures in the system can be represented by
Figure 20.
The major changes were:
1. The system was adjusted to expect more flow to the community, which is likely to happen as more
springs are discovered and protected to feed into the piping network.
2. All tanks were upsized to design size.
3. Flow control valves were installed before each tank. The float valves modeled in the system enforce
a variable headloss based on how full the tank is. As the tank fills, less flow can come through the
float valve. The design headloss coefficients and desired flow entering the tanks are found in Table
6. Control valves installed upstream of each tank should be set so the flow is as close to and at least
its design value.
Table 6. Design Headloss Coefficients, Allowed Maximum Flow
Tank
PBT1
PBT2
PBT3
PBT4
PBT5
PBT6
PBT SIDE
Headloss
Coefficient (k)
105
70
75
135
240
1280
20000
Desired
Flow (L/s)
9.976
9.928
9.544
8.080
5.368
2.704
0.192
4. The first link of the pipe connecting the side tank to the main line was replaced so that it split off
where the pipe diameter switches from 90 mm to 75 mm. This mitigated negative pressures at
households between the main line and side tank.
5. Certain pipes were upsized to give better pressure results. The new pipe design sizes were based
on Church’s Method.
6. A new loop upstream in the community was added to accommodate movement and growth.
35
36
Figure 20. Pressure Values at 13:30 Hours under Maximum Day Demands in 20 Years
5.2.2RevisedSystemMap
The revised system map was created using the revised survey data which was corrected in ArcMap. This
system map was created similarly to the first one but with more accuracy. A road shapefile was created in
ArcMap using the road survey points as well as a background map. This road GIS shapefile was then
converted to a drawing file which was then loaded into AutoCad. From ArcMap, the tanks, house, and
church survey points were put into survey databases in AutoCad Civil3D. This was done by making the
ArcMap into a comma separated version (.csv) file and then loading this data into AutoCad Civil3D. As a
survey database, the points in the .csv file were shown as individual points in the AutoCad drawing. These
drawing files were then referenced into the master drawing and put on individual layers.
By doing the above procedure, the drawings were all scaled as accurately as possible. The drawings will
not be used as construction drawings but more as a reference for the community. This system map will be
the most accurate representation of the pipe network and house locations the community possesses.
5.2.3TankDesign
The team designed six tanks to increase storage and regulate pressures in the system. The tanks were
designed to hold 40% of the average day demand 20 years from the year of design. The tanks will be located
near the current pressure breaking tanks, at the same elevations. Each storage tank will have a float valve
to maintain the water level and two other valves which will regulate the flow to the tank and allow draining
of the tank if cleaning is necessary. All six tanks will have a design diameter of 5 m, which translates to an
inner-diameter of 4.70 m. The tanks will then vary in height to achieve their nominal design volume with
allowance for extra head space, as found in Table 7. The basic tank design plans were received from Bruce
Rydbeck and tweaked to fit the design tank sizes, which are shown in Figure 21 and Figure 22. Full plan
sets for the tanks are included in the complete plan set found in Appendix E.
Table 7. Tank Design Sizes
Tank
PBT1
PBT2
PBT3
PBT4
PBT5
PBT6
PBT SIDE
Nominal
Volume [m3]
10
5
25
40
40
40
5
37
Nominal
Height [m]
0.6
0.3
1.5
2.4
2.4
2.4
0.3
Design
Height [m]
1.0
1.0
1.6
2.8
2.8
2.8
1.0
Figure 21. Tank Design Front View (Scale 1:40) (Used with permission by Bruce Rydbeck) [12]
Figure 22. Tank Design Top View (Scale 1:40) (Used with permission by Bruce Rydbeck) [12]
38
5.2.4ComparisontoChurch’sMethod
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 8.
Table 8. Church's Method typically used for design of rural water systems in Ecuador [13]
PVC Pipe
Diameter
25
32
40
50
63
75
90
Interior Pipe
Diameter [mm]
22.4
29.0
36.2
45.2
57.0
69.2
81.4
Area [mm2]
394.08
660.52
1029.22
1604.60
2551.76
3761.00
5204.03
Number of
Maximum
Connections
3
10
20
32
50
100
125
The use of such a table allows field staff to make adjustments in the field as they see fit. This method works
especially well, given that distribution systems are typically designed as branching systems for ease of
finding leaks and piping cost reduction. This method of analysis was applied to the current system, and it
was found that 168 homes, over one-third of those in the community, are currently connected to pipes that
are too small. Over 2730 meters of pipes will need to be replaced for the system to be in working order for
the extent of the design life. These increased pipe sizes were tested in the EPANET model, and the
beneficial changes have been suggested in order of increasing advantage. The overall system map with
recommended pipe size changes can be found in Appendix E.
5.2.5ProposedMeters
At the suggestion of community leaders, the team has included water meters as part of the improvement
plan. The purpose of water meters is to monitor water usage at each home, which will allow the local water
board to properly charge each home for their water usage. Because the community asked for this
improvement, the team felt it best to add this to the improvement plan to promote community responsibility
for the entire distribution system.
5.3Chlorination
Since chlorine disinfection of drinking water systems is required by the government of Ecuador, it is
recommended that Apatug reinstate the chlorination of their drinking water, especially if they hope to
receive government funding for future drinking water projects. The key qualities of the chlorine disinfection
system for Apatug should be that it is easy to implement, effective at disinfection, cause minimal taste
issues, and be sustainable. By designing the chlorination in the context of a pilot study, it is hoped that the
implementation and control of the system will be taken over fully by the community, making it successful
and sustainable.
5.3.1ChlorineSourceandStorage
5.3.1.1LiquidSodiumHypochlorite
After evaluating different forms of chlorine, the team recommended that liquid sodium hypochlorite
solution be used to disinfect the water in Apatug. Sodium hypochlorite is readily available as liquid bleach,
39
it is cost-effective, relatively easy to store, and can be easily dosed into the water distribution system using
dosing pumps. The community can purchase sodium hypochlorite solution in the nearby city of Ambato,
although it is recommended that the purchased solution be diluted before storage, as chlorine solutions with
lower concentrations do not degrade as quickly as solutions with higher concentrations of chlorine. A plastic
drum will be used to store the sodium hypochlorite, as shown in Figure 23. Assuming a chlorine dose of
1.5 ppm and source flow of 6 liters per second, a 500 L polyethylene vertical storage tank will provide
sufficient storage for a 1% sodium hypochlorite solution for 6 days. Storage requirement calculations are
included in Appendix F.
Figure 23. Plastic 500 L Drum for Sodium Hypochlorite Storage [14]
5.3.1.2Electrolysis
As a possible source for hypochlorite solution the team recommended that the community of Apatug
investigate the purchase of equipment for electrolysis. Electrolysis can be used to create a sodium
hypochlorite solution by running an electric current through a solution of salt water. There are several
advantages to using electrolysis to produce a hypochlorite solution in the community. First, electrolysis is
a more cost-effective way to chlorinate the drinking water distribution system, eliminating the need for
purchase, transportation, and excess storage of sodium hypochlorite solution. Secondly, producing
hypochlorite onsite will allow Apatug to make chlorine solutions for surrounding communities as well.
The electrolysis equipment should be housed in a building which already receives electricity. Electrolysis
is already being implemented in the community of Santiago de Quito which is about 60 km from Apatug.
In Santiago de Quito, a 1% sodium hypochlorite solution is produced. Currently, communities bring salt to
the clinic, and they can retrieve the hypochlorite solution the following day. Photographs of the electrolysis
equipment located in Santiago de Quito are shown in Figure 24.
40
Figure 24. Electrolysis Equipment Located in Santiago de Quito
5.3.2ChlorineDosing
5.3.2.1DosingPumps
Since electricity is not completely reliable in the community and the flow from the spring can vary, the
team recommends the use of a non-electric fluid-driven proportional dosing pump to deliver chlorine into
the distribution system. Feasible pump options include the MixRite 500, the Dosmatic® MiniDos 2.5%,
and the Dosmatic® SuperDos, which have specification sheets included in Appendix G. The pumps will be
located in the system just before the water from the spring enters into the uppermost reservoir, which is
currently the only existing reservoir in the system. This dosing location will ensure that all drinking water
used by the community is chlorinated, and it will also allow the use of the existing reservoir as a contact
tank to provide adequate disinfection time.
The team recommended the use of the Dosmatic® SuperDos 20 2.5% in Apatug. The SuperDos 20 allows
for a greater flow range than the MiniDos, and it also has the capability to dose at a higher ratio than the
MiniDos at 2.5%. Since the SuperDos 20 2.5% can dose at a higher ratio, it will not have to complete as
41
many cycles as the MiniDos to achieve the same dosing concentration, which reduces wear and increases
the life of the pump.
5.3.2.2ChlorinationBuilding
The pumps will be housed in a chlorination building along with the stored sodium hypochlorite, which is
already constructed next to the reservoir, as shown in Figure 25. A schematic of the existing chlorination
building layout is included in Figure 26, and the details of the pump connections are shown in Figure 27.
Figure 25. The Existing Chlorination Building by the Existing Reservoir
42
Figure 26. Schematic of the Existing Chlorination Building Layout in Apatug
43
Figure 27. Proposed Chlorination Building with Pump Connection and Baffling Structure
44
5.3.2.3DosingConcentrationandCalculations
Chlorine dosing is based on chlorine demand of the source water as well as the desired residual free chlorine
concentration in the system. In the case of Apatug, the source water comes from a protected spring, giving
it a higher water quality compared to surface water or well sources. According to the results of the chemical
analysis of the water performed in Apatug, the water has a very low turbidity, suggesting a very low
concentration of organic material. These parameters suggest that the source water coming into the system
in Apatug will have a relatively low chlorine demand. Since the team does not have adequate results from
a chlorine demand test, a typical chlorine dose of 1.5 mg/L (or 1.5 ppm) chlorine, as suggested by Bruce
Rydbeck, will be assumed for dosing calculations.
The desired residual concentration of free chlorine in throughout the system is 0.3 mg/L, which is based on
the results of a pilot study performed by Bruce Rydbeck and completed in 2013 [15]. This residual
concentration was determined to be sufficient to prevent bacterial growth in the system while minimizing
taste concerns associated with higher chlorine concentrations. The World Health Organization (WHO)
recommends a minimum free chlorine residual concentration of 0.5 mg/L to maintain water quality
throughout the distribution system, while the Safe Water System (SWS) put forth by the Centers for Disease
Control and Prevention (CDC) recommend a minimum residual concentration of 0.2 mg/L to prevent
bacterial growth [16].
Assuming a flow rate through the shunt and injector pump of 0.05 L/s, the dosing ratio on the pump should
be set to 1.8% to achieve a free chlorine dose of 1.5 ppm for the entire flow of 6 L/s. Supporting calculations
for the pump dosing ratio are included in Appendix H.
5.3.2.4ContactTimeandContactTankDesign
Free chlorine requires a certain amount of contact time to achieve disinfection of source water, which is
dependent upon the pH and temperature of the source water as well as the desired residual free chlorine
concentration. Required contact time increases with higher pH and lower temperatures, so a conservative
contact time was calculated using the highest measured pH and lowest expected temperature of the source
water. According to the water chemistry test results, the highest expected pH in Apatug is 8, and the lowest
expected temperature is about 50 °F or 10 °C. Using these parameters and a desired free chlorine residual
of 0.3 mg/L, the required contact time for 3-log removal of Giardia according to the United States EPA is
417 minutes. Calculations used to determine required and existing contact times according to the EPA and
the World Health Organization are provided in Appendix I.
The existing reservoir located at the top of the community is well-placed to be a chlorine contact tank. The
hydraulic residence time of the existing reservoir, given a water volume of 85 m3, is 232 minutes. Since the
existing tank has no baffling structure, there is significant short-circuiting of the chlorinated water in the
tank, resulting in a baffling factor of about 0.1. This low baffling factor gives the existing tank an effective
contact time of 23.2 minutes. In the existing distribution system, the chlorinated drinking water must travel
through a total of 509 m of PVC pipe before reaching the first house, giving the water an additional contact
time of 17 minutes. Since the contact time achieved by the current tank is well below the required contact
time from the US EPA, it was recommended that the community install baffling in the existing tank to
improve the efficiency of tank as a chlorine contact tank. Baffling will increase the T10/T ratio of the contact
tank, where T10 is the time it takes for 10% of the water to pass through the reservoir and T is the hydraulic
residence time or ideal contact time if there were no short-circuiting in the reservoir. A schematic of the
45
tank with the recommended baffling structure is shown in Figure 27. This baffling layout would result in a
baffling factor of 0.3, resulting in a new effective contact time of 69.6 minutes [17]. In addition to the
contact time achieved in the pipe network before the first house, the total chlorine contact time achieved by
the system is approximately 87 minutes.
Another way to improve the effectiveness of the chlorination system would be to increase the free chlorine
residual, which results in a lower required contact time. The desired chlorine residual is well below the
maximum residual disinfectant level (MRDL) set forth by the US EPA of 4.0 mg/L [18]. In the case of
Apatug, taste concerns with over-chlorinated water are a significant concern for the sustainability and
acceptance of the chlorination system. A water age study of the existing system, assuming first order
kinetics for chlorine decay in the distribution system, suggested that with a maximum water age of
approximately 13 hours, free chlorine will only decay by about 0.05 mg/L at the farthest extents of the
system. Calculations for chlorine decay are provided in Appendix J.
5.3.3ChlorineResidualandBacteriologicalMonitoring
5.3.3.1ChlorineResidualMonitoring
To determine the effectiveness and success of the chlorination system, it is necessary to include testing for
chlorine residual throughout the system as well as monitor bacteriological growth. A sufficient chlorine
residual must be maintained to prevent growth of bacteria while ensuring that taste concerns do not prevent
the community from accepting the chlorination system. Because the desired free chlorine residual
throughout the system is 0.3 mg/L, a testing method that is able to measure free chlorine at low
concentrations is required. Test strips, which are commonly used for monitoring chlorine in swimming
pools, are easy to use but do often do not detect chlorine at less than 1 mg/L. Indigo Instruments sell 0-10
ppm Residual Chlorine Test Strips that provide testing of chlorine residual to 0.5 ppm for $48.90 for 150
strips [19].
Another option for chlorine residual monitoring is a Hach Free Chlorine Color Disc Test Kit, Model CN66F, which measures residuals from 0.1 – 3.5 mg/L free chlorine and provides 100 tests for $51.59 [20].
The Hach testing kit is also easy to use, utilizing a color disc to visually determine the free chlorine
concentration. Although this kit is slightly more expensive than the Indigo Instrument test strips, it provides
a more precise reading to 0.1 ppm.
Chlorine residual should be monitored four times per week at the existing reservoir and at key points
throughout the system by takin grab samples. It was recommended that residual concentrations be measured
at the north, downhill end of the community, which is where the water has been in the distribution system
for the longest amount of time. Chlorine residuals should be recorded to track any variation of residual and
to ensure adequate chlorine concentrations are being maintained throughout the system. Residual
monitoring results should be used to make any necessary adjustments of the chlorine dosing ratio into the
system.
5.3.3.2BacteriologicalMonitoring
In addition to chlorine residual monitoring, bacteriological growth should be monitored throughout the
system biweekly. Again, monitoring should be performed throughout the system, particularly at the farthest
extents of the distribution system where the water is the oldest. Chlorine residual should be maintained at
a high enough concentration to prohibit bacterial growth at all points in the system.
46
A Colilert® Test Kit from IDEXX, can be used to determine the presence or absence of bacterial coliforms
in water. The test kit is distributed worldwide, and includes a reagent which will turn yellow in the presence
of coliforms after a 24 hour incubation period. A kit providing 100 tests costs approximately $430 [21].
The Colilert® kit also has the capability to identify E. coli in water samples, but the test requires a
fluorescent lamp. The presence/absence test procedure for coliforms in general is solely a visual test and
should be sufficient for the purposes of the pilot study.
After the conclusion of the pilot study, it is no longer critical to test for coliforms, unless the community
suspects the presence of bacteria in the distribution system. The initial bacteria testing in conjunction with
chlorine residual testing should determine the chlorine residual in the distribution system that needs to be
maintained to prevent bacterial growth.
5.3.4ChlorinationPilotStudy
Due to the nature of the design project, including the recommendation of the use of chlorine dosing pumps
that have not been used in the capacity of a drinking water system and the lack of acceptance of chlorination
in rural Ecuador, the team decided to present the chlorination system design for Apatug in the context of a
pilot study. The client, Bruce Rydbeck, expressed a desire to perform a pilot study to test the effectiveness
of the use of non-electric fluid-driven dosing pumps to chlorinate a distribution system in a way that is easy
to maintain and minimizes negative effects of improper chlorine dosing on taste and bacteriological growth.
A separate pilot study proposal is included in Appendix K, which was given to Mr. Rydbeck and the
community of Apatug for implementation. The objectives, necessary equipment, method, and timeline for
the study were included in this design report.
5.3.4.1Objectives
Through the implementation of the chlorination pilot study, the following objectives are desired.
1. Installation of nonelectric fluid-driven proportional chemical dosing pump in the existing
chlorination building next to the existing reservoir.
2. Determination of appropriate chlorine dosing to achieve a chlorine residual of approximately 0.3
mg/L free chlorine throughout the distribution system.
3. Method for monitoring and recording free chlorine residual and bacteriological growth throughout
the distribution system.
4. Investigation of the use of electrolysis to provide sodium hypochlorite for disinfection in the
community.
5. Monitoring of public acceptance of the chlorination system, including taste issues and ease of use.
6. Determination of the existing reservoir kinetics, particularly the T10/T ratio for the existing tank.
7. Establish a chlorination system that is owned and maintained by the community of Apatug,
resulting in a sustainable and effective chlorination system.
5.3.4.2Equipment
Implementation of the chlorination pilot study requires the installation of a chlorine dosing pump in the
existing chlorination building before the first reservoir in the system. In addition to the dosing pump, pipes,
valves, and a flow meter should be installed. A plastic tank for chlorine storage is also necessary to set up
the chlorine dosing system. A schematic of the proposed chlorination building layout is provided in Figure
27. A summary of the components needed for the chlorination system installation are provided in Table 9.
47
Table 9. Summary of Chlorination System Components for Pilot Study
Dosing Pump
PVC Pipe
Flow Meter
Valves
Quantity
1
2m
2
3
Estimated Cost
$325
$10
$80
$375
In addition to the chlorination system itself, test kits for free chlorine and bacteriological monitoring are
required. Recommended kits are presented in Table 10, and specification sheets for the kits are provided in
Appendix L.
Table 10. Recommended Testing Kits for Monitoring Chlorine Residual and Bacteriological Growth
Kit
Hach Free Chlorine Color Disc Test Kit,
Model CN-66F
Colilert® Test Kit from IDEXX
Number of Tests
100 Free Chlorine
Estimated Cost
$55
100 presence/absence
$430
5.3.4.3Method
5.3.4.3.1DosingPumpInstallation
The first step that the community should take is to install the dosing pump prior to the main reservoir. An
important part of this installation is to utilize a shunt flow so the dosing pump is not overwhelmed. The two
pumps that the ACE Team tested cannot handle the approximate 6 L/s flow that serves the community.
Therefore, a shunt is necessary to divert a portion of the flow through the dosing pump apart from the main
line. A shunt flow is also beneficial during pump maintenance, allowing water to bypass the pump and flow
to the tank even when the pump is disconnected, as shown in Figure 27. The community will also need to
dose the chlorine proportional to the diverted flow. It is assumed that the water will be dosed with a 1%
sodium hypochlorite solution, which will be supplied by the community.
5.4.3.3.2ChlorineDemandTest
Before beginning the chlorination of the distribution system, it was recommended that the community
perform a chlorine demand test to determine the amount of chlorine that is consumed when disinfecting the
source water. This chlorine demand will inform the recommended dose of free chlorine into the system,
which should be equivalent to the chlorine demand added to the desired chlorine residual of 0.3 mg/L.
A chlorine demand test can be performed using the Hach free chlorine test kit. Chlorine demand is
determined by the amount of chlorine consumed during disinfection by a certain volume of water. Chlorine
demand can be measured by dosing a known volume of sample water with a known dose of chlorine and
then measuring the residual concentration of free chlorine in the sample after a contact time of
approximately thirty minutes.
5.4.3.3.3TracerStudytoDetermineContactTankEfficiency
As part of the pilot study, the community has the opportunity to implement a tracer study to determine the
amount of short-circuiting in the existing reservoir at the start of chlorination. When chlorine is first
introduced into the system, the free chlorine concentration leaving the reservoir can be measured at intervals
48
until the concentration leaving the tank stabilizes. When chlorine is dosed at a constant ratio, the time at
which the free chlorine concentration reaches a steady value is the effective contact time, or T10 of the tank.
This study can result in a more accurate baffling factor value for the tank in Apatug as well as for similar
tanks being used in other communities in rural Ecuador.
5.4.3.3.4ChlorineResidualandBacteriologicalGrowthMonitoring
Chlorine residual monitoring should be performed throughout the system as soon as chlorine dosing begins.
The Water Board of Apatug should assign an individual to perform and record the chlorine residual
monitoring during the course of the pilot study and weekly during normal maintenance of the system.
Chlorine residual monitoring should be performed immediately after the chlorine contact tank, at the north
end of the community, and at a few key points throughout the distribution system. Recommended sampling
locations are indicated in Figure 28.
Bacteriological monitoring should be performed in conjunction with chlorine residual testing to assess the
effectiveness of the residual concentration in preventing bacterial growth. Bacteriological monitoring is
more expensive to perform, and it requires incubation of water samples at 35 °C (95 °F) for 24 hours. It is
recommended that an outside party with access to an incubator and sterilized equipment assist the
community of Apatug during the water testing portion of the pilot study. Since testing for coliforms is more
expensive than chlorine residual testing, bacteriological monitoring should be performed biweekly at test
sites 3, 7, 8, and 10, as shown in Figure 28. Coliform tests should always be performed in conjunction with
chlorine residual testing so that a minimum chlorine residual concentration to preclude bacterial growth in
the system can be determined.
In addition to water testing, the Water Board should monitor the public receptivity of the chlorination of
drinking water, including the location and date of reports of taste concerns. The dosing of sodium
hypochlorite should be adjusted to maintain chlorine residuals of approximately 0.3 mg/L throughout the
system, or to a level that can be shown to prevent bacterial growth without major taste concerns.
49
50
5.3.4.4Timeline
The first step in the implementation of the pilot study is installation of the dosing pumps, including
additional pipes and valves, as well as the purchase and storage of sodium hypochlorite. A chlorine demand
test of the system can be completed as soon as the free chlorine test equipment is acquired. A timeline for
the pilot study is shown graphically in Figure 29.
1
2
3
•Obtain necessary equipment, includes pumps, valves, chlorine solution and storage tank, and test kits.
•Install chlorine dosing system just before the existing reservoir.
•Implement the tracer study to determine the effective contact time obtained in the existing reservoir.
4
•Test chlorine residual concentration four times per week.
•Test for bacterial coliforms two times per week.
•Monitor public acceptance of chlorination.
5
•Investigate electrolysis.
•Continue to monitor residual chlorine.
Six week duration Figure 29. Pilot Study Timeline Summary
The tracer study to determine the baffling factor in the tank should be implemented when chlorine is first
dosed into the system, allowing the effective contact time of the existing reservoir to be adequately
measured.
Chlorine residual and bacteriological monitoring should be performed for the first six weeks in which the
chlorination system is operating. Chlorine residual should be measured at ten locations throughout the
community five days a week for six weeks. Coliforms should be monitored at four locations throughout the
community two days a week for six weeks, always in conjunction with a chlorine residual test. Chlorine
residual monitoring should continue regularly, even after completion of the pilot study. Consistent residual
monitoring will allow the community to determine an optimal chlorine dose for the distribution system to
ensure drinking water is disinfected without compromising taste. During the pilot study, community
receptivity and response to the chlorination system should be also closely monitored and recorded by the
Water Board.
The Water Board is encouraged to investigate the implementation of electrolysis in Apatug to produce
sodium hypochlorite for the community. In the event that electrolysis equipment is acquired, the strength
of the chlorine solution produced should be measured using the free chlorine testing kit.
51
5.4Costing
The following is a detailed cost analysis of the proposed system updates. The following cost information
was obtained from a spreadsheet that Bruce Rydbeck had produced for the community of Apatug. Table 11
shows a breakdown of the overall costs of the proposed changes, to an estimated total of $174,662.22.
Table 11. Overall Costs of Proposed Changes
Cost
$ 112,775.00
Distribution
tanks
Pipes
Meters
Valves
Pilot study
Total
$
14,113.94
$
33,150.00
$
12,460.00
$
2,163.28
$ 174,662.22
5.4.1DistributionSystemImprovementsCost
The majority of costs surrounding distribution system improvements are increasing the size of the tanks.
Existing pipes will have to be replaced with pipes of larger diameters if the system is to remain functional
through its design life. Roughly 2730 m of pipe were recommended to be replaced, which will cost around
$15,000. The main cost is from the construction of much larger storage tanks than already exists. Table 12
shows a cost breakdown for the tank construction based on a unit cost of $400/m3 [22].
Table 12. Increased Water Storage Costs
Actual Size [m3]
Tank 1
Tank 2
Tank 3
Tank 4
Tank 5
Tank 6
Tank Side
17.35
17.35
27.76
48.58
48.58
48.58
17.35
Total
x1.25 contingency
Cost
$
$
$
$
$
$
$
$
$
6,940.00
6,940.00
11,104.00
19,432.00
19,432.00
19,432.00
6,940.00
90,220.00
112,775.00
5.4.2ChlorinationDosingSystemCost
The cost of the chlorination dosing system will equal the cost of the pilot study for the length of time for
which the pilot study is run. If the pilot study is found to be successful, the cost of the dosing system will
simply be the cost per month of chlorine solution. Table 13 shows the cost breakdown for the equipment
for the dosing of the drinking water.
52
Table 13. Pilot Study Cost Breakdown
Pump
Valves
Flow meter
Pipe
Sodium hypochlorite
Chlorine test kits
Coliform test kits
Chlorine Tank
Quantity
1
3
2
10
67.5
4
1
1
Unit Cost
$
325.00
$
125.00
$
40.00
$
5.00
$
0.75
$
55.00
$
430.00
$
200.00
Total
x1.25 contingency
$
$
$
$
$
$
$
$
$
$
Cost
325.00
375.00
80.00
50.00
50.63
220.00
430.00
200.00
1,730.63
2,163.28
If the pilot study is found to be successful, the community will continue chlorination and this will result in
monthly sodium hypochlorite and testing material cost. Based on the dosing and flow rate, the monthly
usage of chlorine will be about 45 kilograms of sodium hypochlorite, which translates to a cost of $33.75
per month. The testing will cost about $27.50 per month if the ten sites around the community are tested
once per week for chlorine residual. Multiply by a 25% contingency factor, and the total cost of chlorination
to the community is roughly $76.50 per month.
5.4.3CommunityRate
The team recommends that the community be charged a rate of $1.00 per month plus $0.10 per m3 of water
over the use of 5 m3. This rate is low compared to other communities the team visited, which are charged
$0.50/m3 to $0.75/m3 for systems that require pump stations. However, since the system in Apatug is
entirely gravity-fed, there are lower maintenance costs and the rates can be lowered while still providing
enough funds for maintaining the system. These costs are recommended, but the Water Board of Apatug
will ultimately be responsible for selecting a metering rate for the community.
5.5Maintenance
Maintenance of the system will be supervised by the Water Board of Apatug. The Water Board is in charge
of making all the decisions pertaining to the distribution system. Even though the Water Board is in charge
of making the decisions, the community is the one that does most of the work for the system. If the
community believes in the distribution system and it is serving the community properly, then they will want
to keep the system operating at this level.
5.6Sustainability
The key to making the distribution system sustainable is to get as much community involvement as possible.
This will be crucial during the chlorination pilot study. If the community does not trust the chlorination,
they will not drink the water and, consequently, ignore the system. By having the community take
ownership of the system, they will take better care of the system and therefore replacements should happen
less often.
53
Community ownership was also encouraged during the team's visit to the community. By asking for the
input of the community in design decisions, those who live in Apatug become part of the process and will
feel incorporated in the work that will improve their community.
The relationship between the community and engineer Efrain Morocho, who works with Bruce Rydbeck,
is also important to the system's sustainability. In order to ensure that systems that have been built or rebuilt
remain in working order, Efrain makes quarterly visits to the communities to check up on the systems. If
problems are encountered that need his help, Efrain will assist in the repair, otherwise he will remind the
community that they have the tools to fix the problems themselves. This relationship is important as it
provides a guiding hand in the maintenance process for the communities as they take on ownership.
Community ownership is one of the large steps to making sure that the system is sustainable.
Chlorination itself is another way that the system can be sustainable for years to come. Not only will the
chlorine disinfect the water, it will leave a residual throughout the system ensuring that no bacteria buildup
inside the pipes occurs. If for some reason, the protected spring that feeds the system gets compromised,
the chlorine will be able to disinfect bacteria that enter the system. Since the mountain water feeding the
system currently is already very clean, the chlorine residual in the pipes is not necessary to make the water
potable. However, the chlorine will make the system more sustainable in the future making sure that no
bacterial growth occurs inside of the pipes.
Another way that sustainability played into the recommendations for implementation of the design was to
suggest that the materials and construction practices were common to rural Ecuador. This ensured that the
community could understand how the system should be put in. One problem foreseen with this aspect of
sustainability will be the implementation of the chlorine dosing pump. The pump that will be used is not a
pump commonly used in Ecuador. The main way that this issue was addressed was providing specific
instructions for use in the pilot study.
Finally, if the community were to look into electrolysis, the system could become even more sustainable.
By producing the chlorine solution on or near the site of disinfection rather than transporting, the
disinfection process becomes simpler and easier to maintain.
5.7Conclusion
The ACE team believes that if the city of Apatug implements the three year plan outlined in this report, the
current water distribution system will be able to sustain the community for twenty years including the
projected growth over those twenty years. The outlined pilot study will allow for the community to really
take ownership of the chlorination process. Not only will the chlorination design allow Apatug to
successfully chlorinate their drinking water, the Ecuadorian government will help with funding the system
because of the chlorination.
From the team's perspective, a number of lessons were learned through the senior design process. First, the
team learned how vital communication and understanding can be. The team spent first semester designing
a completely new system which in fact was not needed. If the team had understood that the current system
was still functional, time could have been better spent analyzing the current system or looking into other
disinfection methods. Second, the team was humbled through some of its work. Although the team traveled
to Ecuador with the intent of performing extensive water testing, once the testing began, the team realized
54
not only was the chemical testing materials expired, but the team's testing process unrefined. The team
learned the importance of double-checking materials as well as processes to best ensure quality work.
If the project were to continue, the team would like to test other non-electric fluid-driven pumps and also
further investigate electrolysis as a method of chlorine production. First, while the team believes that it has
recommended the best pump given Apatug's situation, the breadth of this specific industry and the amount
of pumps on the market are unknown, and a better pump might be available. Second, the team would spend
some time looking into electrolysis and the feasibility of using this method of chlorine production in the
community. Electrolysis is used to some extent in Ecuador, and it could be beneficial for the community of
Apatug to produce its chlorine in this manner.
55
6.ACKNOWLEDGEMENTS
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; Scott Prentice of the Calvin College Biology Department and Jeremiah Rocha for their
assistance in the use of the Ion Chromatograph machine for water testing. 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 and contacts necessary to make this project successful; Cherith
Rydbeck of Life Giving Water International for coordinating our trip to Ecuador in January; Efrain
Morocho of CODEINSE Ecuador for his assistance in Ecuador and follow-up work in Apatug; Cesar Cortez
of Reach Beyond for providing GPS data of Apatug and answering the questions of the team; and the
Apatug Water Board for their collaboration, expertise, and guidance toward understanding the current
system and future needs of the community; the DeGroot family for providing financial assistance which
allowed the team to purchase two pumps for the bench study.
56
7.REFERENCES
[1]
"Calvin College Engineering," [Online]. Available:
http://www.calvin.edu/academic/engineering/about/mission.html.
[2]
Google, "Google Earth".
[3]
B. Rydbeck, [Email Correspondence]. 15 October 2014.
[4]
B. Rydbeck, [Email Correspondence]. 10 September 2014.
[5]
2012.
B. V. Rydbeck and M. Yamez, "Sustainable Water Quality for Rural Ecuadorian Communities,"
[6]
United Nations Economic and Social Council, "General Comment No. 15," 29 November 2002.
[Online]. Available: http://www2.ohchr.org/english/issues/water/docs/CESCR_GC_15.pdf. [Accessed 5
December 2014].
[7]
United Nations Department of Economic and Social Affairs (UNDESA), "International Decade
for Action 'WATER FOR LIFE' 2005-2015," 5 May 2014. [Online]. Available:
http://www.un.org/waterforlifedecade/human_right_to_water.shtml. [Accessed 5 December 2014].
[8]
United Nations, "Millennium Development Goals and Beyond 2015," [Online]. Available:
http://www.un.org/millenniumgoals/environ.shtml. [Accessed 5 December 2014].
[9]
Republic of Ecuador, "Constitution of 2008," 31 January 2011. [Online]. Available:
http://pdba.georgetown.edu/Constitutions/Ecuador/english08.html. [Accessed 20 September 2014].
[10]
B. Rydbeck, [Email Correspondence]. 19 September 2014.
[11]
American Water Works Association, Distribution Network Analysis for Water Utilities M32,
Denver, CO: American Water Works Association, 1989.
[12]
B. Rydbeck, [Email Correspondence]. 4 February 2015.
[13]
J. C. Church, Practical Plumbing Design Guide, New York: McGraw-Hill, Inc., 1979.
[14]
"Ditecnia.com," [Online]. Available:
http://www.ditecnia.com.ec/files/documentos/Plastigama/Costruccion/Tanques-de-polietileno.PDF.
[Accessed 23 April 2015].
[15]
B. V. Rydbeck and B. Vander Plas, "Rural Water System Disinfection Pilot Project for
Carabuela, Ecuador," 2013.
[16]
World Bank, "World Development Indicators," [Online]. Available:
http://data.worldbank.org/data-catalog/world-development-indicators. [Accessed 2 November 2014].
[17]
B. Rush, "CT Disinfection Made Simple," Water-Research.net.
57
[18]
United States Environmental Protection Agency, "Water: Basic Information about Regulated
Drinking Water Contaminants," US EPA, 13 December 2013. [Online]. Available:
http://water.epa.gov/drink/contaminants/basicinformation/disinfectants.cfm [Accessed 1 May 2015].
[19]
I. Instruments, "0-10ppm Residual Chlorine Test Strips," [Online]. Available:
http://www.indigo.com/test_strips/water_testing/33815-10ppm-chlorine-test-strips-residual-leveldialysis.html#.VTvYY_lT7OA. [Accessed 25 April 2015].
[20]
Hach, "Free Chlorine Color Disc Test Kit, Model CN-66F," [Online]. Available:
http://www.hach.com/free-chlorine-color-disc-test-kit-model-cn-66f/product?id=7640219520. [Accessed
25 April 2015].
[21]
W. Scientific, "Colilert(R) and Colisure(R) IDEXX," Weber Scientific, [Online]. Available:
http://www.weberscientific.com/colilert-and-colisure-idexx. [Accessed 5 May 2015].
[22]
B. Rydbeck, [Email Correspondence]. 5 May 2015.
58
Appendices Table of Contents
Appendix A – Disinfection Decision Matrices
Appendix B – Trip Schedule
Appendix C – Gantt Chart
Appendix D – Hach Nine Parameter Test Kit
Appendix E – Complete Plan Set
Appendix F – Storage Requirement Calculations
Appendix G – Pump Specification Sheets
Appendix H – Pump Dosing Ratio Calculations
Appendix I – Chlorine Contact Time Calculations
Appendix J – Chlorine Decay Calculations
Appendix K – Report for Apatug and Chlorination Pilot Study Proposal
Appendix L – Chlorination Pilot Study Test Kits Specifications Sheets
AppendixA–DisinfectionDecisionMatrices
Figure A.1. Decision Matrix for Chlorine Dosing Method
Figure A.2. Decision Matrix for Disinfection Chemical
A-1
AppendixB–TripSchedule
B-1
AppendixC–GanttChart
C-1
ID
Task
Mode
Task Name
Duration
Start
Finish
T
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
Project: ProjectDraft1
Date: Mon 12/8/14
W
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F
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Milestone
Inactive Summary
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ID
Task Name
Duration
Start
Finish
Primary
Assignment
Secondary
Assignment
GPS data process
13 days
Thu 2/5/15
Mon 2/23/15
Nathan
Julie
2
Check GPS vs. Survey
5 days
Mon 3/2/15
Fri 3/6/15
3
Correct Survey data
2 days
Thu 2/5/15
Fri 2/6/15
Julie
Nathan
Julie
4
AutoCAD Drawings
61 days
Fri 2/13/15
Wendy
Fri 5/8/15
Jeremy
5
Survey data process
13 days
Thu 2/5/15
Mark
Mon 2/23/15
Julie
6
Survey data to EPANET
2 days
Jeremy
Tue 2/24/15 Wed 2/25/15 5
Julie
7
Create exisiting model
Jeremy
39 days
Thu 2/26/15 Tue 4/21/15
6
Wendy
8
Jeremy, Mark
Revise system w/ improvement
9 days
Wed 4/22/15 Mon 5/4/15
7
Wendy
Jeremy
9
Put Chlorine info in EPANET
10 days
Wed 4/22/15 Tue 5/5/15
7
Nathan
Julie
10
Check design with Church's Method
3 days
Mon 4/27/15 Wed 4/29/15
Mark
Wendy
11
Tank Design Plan Sheets
1 day
Wed 2/4/15
Wed 2/4/15
Mark
Wendy
12
Chlorine demand calculations
2 days
Thu 2/5/15
Fri 2/6/15
Mark
Jeremy
13
Do pump calculations to check pumps
2 days
Thu 2/5/15
Fri 2/6/15
Nathan
Julie
14
Order Pumps
1 day
Fri 2/13/15
Fri 2/13/15
Nathan
Julie
15
Check Bench Study plan
6 days
Wed 2/11/15 Wed 2/18/15
Julie
Nathan
16
Set‐up Bench Study
1 day
Fri 3/27/15
Fri 3/27/15
Julie
Nathan
17
Run Bench Study 1
1 day
Sat 3/28/15
Sat 3/28/15
Nathan
Julie
18
Run Bench Study 2
1 day
Thu 4/2/15
Thu 4/2/15
Julie
Nathan
19
Create 3‐Year Action Plan
7 days
Mon 4/27/15 Tue 5/5/15
Julie
Mark
20
Plan to make Apatug Pilot Study
21 days
Tue 4/7/15
Tue 5/5/15
Julie
Mark
21
Calculate suggested water cost
2 days
Wed 4/8/15
Thu 4/9/15
Mark
Jeremy
22
Total costing information
10 days
Mon 4/27/15 Fri 5/8/15
Mark
Jeremy
23
Trip description
6 days
Mon 2/9/15
Mon 2/16/15
Mark
Wendy
24
Compare communities
6 days
Mon 2/9/15
Mon 2/16/15
Mark
Wendy
25
Compile trip docs
3 days
Fri 2/6/15
Tue 2/10/15
Mark
26
Final Report Outline
1 day
Fri 2/6/15
Fri 2/6/15
Wendy
27
Final Report Draft
4 days
Wed 4/22/15 Mon 4/27/15
ALL
28
Final Report
70 days
Thu 2/5/15
ALL
29
Team Blurbs
3 days
Wed 2/11/15 Fri 2/13/15
Mark
30
Team Description for Program
3 days
Wed 3/25/15 Fri 3/27/15
Mark
Wendy
31
Website Update 1
8 days
Wed 2/11/15 Fri 2/20/15
Julie
Jeremy
32
Website Update 2
8 days
Wed 4/1/15
Fri 4/10/15
Julie
Jeremy
33
Website Update Final
4 days
Wed 5/6/15
Mon 5/11/15
Julie
Jeremy
34
Poster Update
6 days
Wed 3/4/15
Wed 3/11/15
Nathan
Wendy
35
Project Brief
4 days
Wed 2/25/15 Mon 3/2/15
Jeremy
Mark
36
Verbal Presentation 1
3 days
Wed 2/25/15 Fri 2/27/15
37
Verbal Presentation 2
5 days
Mon 4/27/15 Fri 5/1/15
38
Verbal Presentation Final
3 days
Thu 5/7/15
1
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Mode
Project: SecondSemesterGaant
Predecessors
5
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AppendixD–HachNineParameterTestKit
D-1
AppendixE–CompletePlanSet
E-1
AppendixF–StorageRequirementCalculations
F-1
AppendixG–PumpSpecificationSheets
G-1
G-2
G-3
G-4
G-5
G-6
G-7
G-8
AppendixH–PumpDosingRatioCalculations
H-1
AppendixI–ChlorineContactTimeCalculations
I-1
I-2
I-3
I-4
AppendixJ–ChlorineDecayCalculations
J-1
AppendixK–ReportforApatugandChlorinationPilotStudyProposal
K-1
Water Distribution System Analysis and
Recommendation for Apatug, Ecuador
May 2015
Mark De Haan
Jeremy Kamp
Nathan Laframboise
Julie Swierenga
Wendy Tabler
The ACE Team
Calvin College Engineering Senior Design Project
Bruce Rydbeck
Life Giving Water International
I. Purpose
1.1 Distribution System
The purpose of designing water disinfection and improving the current distribution system for Apatug,
Ecuador, is to supply its 520 households with clean water under manageable pressures. 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.” [2] This right is further defined as
“entitling everyone to sufficient, safe, acceptable, physically accessible and affordable water for
personal and domestic uses.” [2] In July 2010, the United Nations (UN) General Assembly explicitly
recognized this right through Resolution 64/292. [3] 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. [4] This distribution system works toward this Development Goal and will
provide the community members of Apatug to their human right of sustainable access to clean drinking
water.
1.2 Chlorination
The purpose of the chlorination design was 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.
Although the community’s spring water source 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. [6] 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.
II. Background
The ACE Team was connected to this project through Bruce Rydbeck, who has been involved in water
distribution projects in Ecuador for more than 34 years and who suggested that the team work with
Apatug. The current water distribution system for the community has been in place more than 25 years,
and now has some community-expressed deficiencies, such as lack of water available from the tap for
the higher elevation part of the community, lack of water meters to regulate usage, and lack of house
connections in the higher elevation part of the community. Additionally, the community had originally
disinfected its water with chlorine when the current water system was put in place; however, that was
more than two decades ago, and the practice has not been continued. While the community has
electricity, it is not available at the location where the dosing will occur, thus requiring a non-electric
pump or alternative dosing method. Additionally, a recent change in Ecuador's water regulations now
requires chlorine disinfection. With this change, opportunity arose to not only address Apatug's need for
chlorination, but to do so by testing a new method of chlorine application while designing
improvements for Apatug's current water system.
May 2015
Pg. 1
Apatug was determined to be a good candidate for this pilot study for a number of reasons. First, in
order to receive monetary assistance from the government in the improvement of its water distribution
system, the community must chlorinate its water. Second, because the spring which Apatug receives its
water from is protected, the water is of a very high quality and there is little concern regarding
disinfection by-products due to consistent biological makeup of the water. Finally, the community has
an active water board, or “Junta de Agua Potable”, that would like to improve its distribution system
and has expressed interest in continuing the work of the pilot study once it has been turned over to
them.
The work that the community members will perform includes the improvement of the distribution
system, the implementation of the dosing system, as well as the monitoring of the resulting chlorine
levels. Distribution system improvements will require participation from the community, procurement
of materials, and fundraising to support the efforts. Implementation of the chlorination system will
require alterations of the current piping at the main reservoir in order to create a shunt flow. Chlorine
level monitoring, on the other hand, will just be testing of the water at different taps or spigots
throughout the system to determine the residual.
III. Water Distribution System
3.1 Areas of Concern
The concerns brought to the attention of the team by the community leaders include a lack of water in
the higher elevation part of the community during the day and a lack of accountability for water usage
due to an absence of meters. Currently, homes located above the main stadium area, where Tank 5 is
located as shown in Figure 1, are not able to sustain significant water pressures at high demands. To
address this issue, the team created a hydraulic model of the current system to recreate the pressure
issues. This model showed the pipe network, as drawn by the Junta de Agua Potable, with houses
grouped together based on elevation and proximity.
According to the model, the current system contains numerous deficiencies. First, the pressure breaking
tanks are too small to mitigate peak fluctuations and are too small to provide any sort of storage. The
tanks are constantly refilling (2-5 times per hour), and when tanks downstream fill at the same time,
they cause negative pressures at the upstream end of the system. The houses represented by the 2
nodes on the pipeline branching off from the main line to connect with the side pressure breaking tank
(see Figure 2) experience negative pressures at 4 times throughout the day and fluctuate between 65 m
of pressure and 8 m of pressure for the rest of the day.
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Pg. 2
Figure 1. System Model with Pressure Breaking Tank (PBT) Labels
May 2015
Pg. 3
RESERVOIR
Upstream
Reservoir
PBT 1
PBT SIDE
Pressure Breaking Tank (PBT)
LEGEND
 House Group
PBT 2
PBT 3
PBT 4
PBT 5
Downstream
PBT 6
Upstream
Nodes of
Interest
Reservoir
LEGEND
 House Group
Pressure Breaking Tank (PBT)
Figure 2. System Map Showing Location of Nodes of Interest (Negative Pressures)
May 2015
Pg. 4
3.2 Recommended Improvements
The team proposes the construction of larger storage tanks in place of the pressure-breaking tanks
currently employed in Apatug, using another hydraulic model to simulate the recommended system. All
pipe upsizing was determined by Church’s Method under 20 year growth, and the hydraulic model was
used to prioritize both new tank construction and this pipe upsizing. Part of the team’s recommendation
also includes a procedure for new tank construction to ensure that existing water service is not
interrupted. The final plan set with complete recommendations is attached.
These recommendations eliminate negative and undesirable low pressures from the systems, leave
room for new growth in the higher elevation part of the community, and allow the tanks to only fill
about 1-3 times per day.
3.3 Three-Year Recommendation Plan
The three-year recommendation plan is summarized by Figure 3.
Figure 3. System Map Displaying Major Improvements
Year One
1. Increase size of the 2 pressure-breaking tanks at the bottom of the community (Tanks 5 and 6) to
mitigate negative pressures as Tanks 4 and 5 refill as shown in Figure 4
May 2015
Pg. 5
Figure 4. Lowest Pressures as Tanks 4 and 5 Refill, with Increased Tank 5 and 6 Size
2. Move Side Tank connection into main network to where diameter changes from 90 mm to 75 mm
between the reservoir and Tank 1
3. Increase the pipe size of the southeast most branch from 20 mm to 50 mm
4. Install chlorine dosing pump and flow meters and purchase sodium hypochlorite
5. Begin implementation of pilot study
6. Protect exposed pipe between Splitting Tank and Main Reservoir
Year Two
1. Increase size of next two upstream pressure breaking tanks (Tanks 3 and 4) to mitigate low pressures,
as shown in Figure 5
May 2015
Pg. 6
Figure 5. Lowest Pressures as Tanks 4 and 5 Refill, with Increased Tanks 3-6 Size
2. Increase pipe size of most southerly branch off of Tank 6 from 20 mm to 40 mm
3. Increase pipe off of the Side Tank from 20 mm to 40 mm
4. Investigate use of electrolysis for sodium hypochlorite production
5. Install water meters
6. Continue to monitor chlorine residual
Year Three
1. Construct remaining three storage tanks (Tanks 1 and 2 and Side Tank)
2. Increase pipe size of loop between Tanks 4 and 5 from 40 mm to 90 mm
3. Increase pipe size of easterly most pipe from 20 mm to 32 mm
4. Add 50 mm loop in the upstream part of community between Tanks 2 and 3
May 2015
Pg. 7
5. Consider installation of baffling in uppermost reservoir to improve tank efficiency
6. Continue to monitor chlorine residuals and water demand
IV. Chlorination Pilot Study
Since chlorine disinfection of drinking water systems is required by the government of Ecuador, it is
recommended that Apatug reinstate the chlorination of their drinking water, especially if they hope to
receive government funding for future drinking water projects. The chlorination system has been
designed as a pilot study so that the implementation and control of the system will be taken over fully
by the community.
4.1 Chlorine Source and Storage
4.1.1 Liquid Sodium Hypochlorite
The team recommends that liquid sodium hypochlorite solution be used to disinfect the water in
Apatug. Sodium hypochlorite is readily available as liquid bleach, it is cost-effective, relatively easy to
store, and can be easily dosed into the water distribution system using dosing pumps. It is
recommended that the purchased solution be diluted before storage, as chlorine solutions with lower
concentrations do not degrade as quickly as solutions with higher concentrations of chlorine. A plastic
drum can be used to store the sodium hypochlorite, as shown in Figure 6. Assuming a chlorine dose of
1.5 ppm and source flow of 6 liters per second, a 500 L polyethylene vertical storage tank will provide
sufficient storage for a 1% sodium hypochlorite solution for 6 days.
Figure 6. Plastic 500 L Drum for Sodium Hypochlorite Storage
May 2015
Pg. 8
4.2 Chlorine Dosing
4.2.1 Dosing Pumps
The team recommends the use of a non-electric fluid-driven proportional dosing pump to deliver
chlorine into the distribution system. The Dosmatic® SuperDos20 is able to dose flows between 0.05 and
20 gallons per minute (0.003 and 2.5 L/s) and dose at 0.025% to 10%. The specification sheet for the
SuperDos is attached. The pump should be located in the system just before the water from the spring
enters into the uppermost reservoir, which will also act as a contact tank to provide adequate
disinfection time.
4.2.2 Chlorination Building
The pumps will be housed in a chlorination building, along with the stored sodium hypochlorite, which is
already constructed next to the reservoir, as shown in Figure 7.
Figure 7. Proposed Chlorination Building with Pump Connection and Baffling Structure.
May 2015
Pg. 9
4.2.3 Dosing Concentration and Calculations
Chlorine dosing is based on chlorine demand of the source water as well as the desired residual free
chlorine concentration in the system. According to the results of the chemical analysis of the water
performed in Apatug, the water has a very low turbidity, suggesting a very low concentration of organic
material. These parameters suggest that the source water coming into the system in Apatug will have a
relatively low chlorine demand. Since the team does not have adequate results from a chlorine demand
test, a typical chlorine dose of 1.5 mg/L (or 1.5 ppm) chlorine, as suggested by Bruce Rydbeck, will be
assumed for dosing calculations.
The desired residual concentration of free chlorine in throughout the system is 0.3 mg/L, which is based
on the results of a pilot study performed by Bruce Rydbeck and completed in 2013.
Assuming a flow rate through the shunt and injector pump of 0.05 L/s, the dosing ratio on the pump
should be set to 1.8% to achieve a free chlorine dose of 1.5 ppm for the entire flow of 6 L/s.
4.2.4 Contact Time and Contact Tank Design
Proper disinfection of the water using chlorine is dependent upon the pH and temperature of the source
water as well as the desired residual free chlorine concentration. The highest expected pH in Apatug is
8, and the lowest expected temperature is about 50 °F or 10 °C. Using these parameters and a desired
free chlorine residual of 0.3 mg/L, the required contact time for 3-log removal of Giardia according to
the United States EPA is 417 minutes.
The existing reservoir located at the top of the community is well-placed to be a chlorine contact tank.
The hydraulic residence time of the existing reservoir, given a water volume of 85 m 3, is 232 minutes.
Since the existing tank has no baffling structure, there is significant short-circuiting of the chlorinated
water in the tank, resulting in a baffling factor of about 0.1. This low baffling factor gives the existing
tank an effective contact time of 23.2 minutes. In the existing distribution system, the chlorinated
drinking water must travel through a total of 509 m of PVC pipe before reaching the first house, giving
the water an additional contact time of 17 minutes. Since the contact time achieved by the current tank
is well below the required contact time from the US EPA of 417 minutes, it is recommended that the
community install baffling in the existing tank to improve the efficiency of tank as a chlorine contact
tank. A schematic of the tank with the recommended baffling structure is shown in Figure 7, resulting in
a new effective contact time of 69.6 minutes. In addition to the contact time achieved in the pipe
network before the first house, the total chlorine contact time achieved by the system is approximately
87 minutes.
A water age study of the existing system, assuming first order kinetics for chlorine decay in the
distribution system, suggested that with a maximum water age of approximately 13 hours, free chlorine
will only decay by about 0.05 mg/L at the farthest extents of the system.
May 2015
Pg. 10
4.3 Chlorine Residual and Bacteriological Monitoring
4.3.1 Chlorine Residual Monitoring
Residual testing is an important part of the study to guarantee that a sufficient chlorine residual
concentration is maintained to prevent growth of bacteria while ensuring that taste concerns do not
prevent the community from accepting the chlorination system. Because the desired free chlorine
residual throughout the system is 0.3 mg/L, a testing method that is able to measure free chlorine at low
concentrations is required.
One option for chlorine residual monitoring is a Hach Free Chlorine Color Disc Test Kit, Model CN-66F,
which measures residuals from 0.1 – 3.5 mg/L free chlorine and provides 100 tests for $51.59. The Hach
testing kit is also easy to use, utilizing a color disc to visually determine the free chlorine concentration.
Although this kit is slightly more expensive than Indigo Instrument test strips, it provides a more precise
reading to 0.1 ppm.
Chlorine residual should be monitored four times per week at the existing reservoir and at key points
throughout the system. It is recommended that residual concentrations be measured at the north,
downhill end of the community, which is where the water has been in the distribution system for the
longest amount of time. Chlorine residuals should be recorded to track any variation of residual and to
ensure adequate chlorine concentrations are being maintained throughout the system. Residual
monitoring results should be used to make any necessary adjustments of the chlorine dosing ratio into
the system.
4.3.2 Bacteriological Monitoring
In addition to chlorine residual monitoring, bacteriological growth should be monitored throughout the
system biweekly. Again, monitoring should be performed throughout the system, particularly at the
farthest extents of the distribution system where the water is the oldest. Chlorine residual should be
maintained at a high enough concentration to prohibit bacterial growth at all points in the system.
A Colilert® Test Kit from IDEXX, can be used to determine the presence or absence of bacterial coliforms
in water. The test kit is distributed worldwide, and includes a reagent which will turn yellow in the
presence of coliforms after a 24 hour incubation period. A kit providing 100 tests costs approximately
$430. The Colilert® kit also has the capability to identify E. coli in water samples, but the test requires a
fluorescent lamp. The presence/absence test procedure for coliforms in general is solely a visual test
and should be sufficient for the purposes of the pilot study.
After the conclusion of the pilot study, it is no longer critical to test for coliforms, unless the community
suspects the presence of bacteria in the distribution system. The initial bacteria testing in conjunction
with chlorine residual testing should determine the chlorine residual in the distribution system that
needs to be maintained to prevent bacterial growth.
4.4 Chlorination Pilot Study Proposal
4.4.1 Objectives
Through the implementation of the chlorination pilot study, the following objectives are desired.
May 2015
Pg. 11
1. Installation of non-electric fluid-driven proportional chemical dosing pump in the existing
chlorination building next to the existing reservoir.
2. Determination of appropriate chlorine dosing to achieve a chlorine residual of approximately 0.3
mg/L free chlorine throughout the distribution system.
3. Method for monitoring and recording free chlorine residual and bacteriological growth
throughout the distribution system.
4. Investigation of the use of electrolysis to provide sodium hypochlorite for disinfection in the
community.
5. Monitoring of public acceptance of the chlorination system, including taste issues and ease of
use.
6. Determination of the existing reservoir kinetics, particularly the T10/T ratio for the existing tank.
7. Establish a chlorination system that is owned and maintained by the community of Apatug,
resulting in a sustainable and effective chlorination system.
The chlorine levels will be monitored at homes and spigots around the community. Given proper dosing
and contact time, residual chlorine levels should not vary at homes around the community nor should
they be effected by reservoir storage.
The water will also have to be tested for coliform formation. Given the fact that the spring is protected
there is little concern for coliform formation. Still, in order to maintain the water's high quality, it should
be monitored for coliform.
4.4.2 Equipment
Implementation of the chlorination pilot study requires the installation of a chlorine dosing pump in the
existing chlorination building before the first reservoir in the system. In addition to the dosing pump,
pipes, valves, and a flow meter should be installed. A plastic tank for chlorine storage is also necessary
to set up the chlorine dosing system. A schematic of the proposed chlorination building layout is
provided in Figure 7. A summary of the components needed for the chlorination system installation are
provided in Table 1.
Table 1. Summary of Chlorination System Components for Pilot Study.
Pump
Valves
Flow meter
Chlorine storage tank
Pipe
Quantity
1
3
2
1
10
Unit Cost
$
325.00
$
125.00
$
40.00
$
200.00
$
5.00
Total
x1.25 contingency
Estimated Cost
$
325.00
$
375.00
$
80.00
$
200.00
$
50.00
$ 1,030.00
$ 1,287.50
In addition to the chlorination system itself, test kits for free chlorine and bacteriological monitoring are
required. Recommended kits are presented in Table 2, and specification sheets for the kits are attached.
May 2015
Pg. 12
Table 2. Recommended Testing Kits for Monitoring Chlorine Residual and Bacteriological Growth.
Kit
Hach Free Chlorine Color Disc Test Kit,
Model CN-66F
Colilert® Test Kit from IDEXX
Number of Tests
100 Free Chlorine
100 presence/absence
Estimated Cost
$55
$430
4.4.3 Method
4.4.3.1 Dosing Pump Installation
The first step that the community should take is to install the dosing pump prior to the main reservoir.
An important part of this installation is to utilize a shunt flow so the dosing pump is not overwhelmed.
The recommended Dosmatic® SuperDos20 cannot handle the approximate 6 L/s flow that serves the
community. Therefore, a shunt is necessary to divert a portion of the flow through the dosing pump
apart from the main line. A shunt flow is also beneficial during pump maintenance, allowing water to
bypass the pump and flow to the tank even when the pump is disconnected, as shown in Figure 7. The
community will also need to dose the chlorine proportional to the diverted flow. It is assumed that the
water will be dosed with a 1% sodium hypochlorite solution, which will be supplied by the community.
4.4.3.2 Chlorine Demand Test
Before beginning the chlorination of the distribution system, it is recommended that the community
perform a chlorine demand test to determine the amount of chlorine that is consumed when
disinfecting the source water. This chlorine demand will inform the recommended dose of free chlorine
into the system, which should be equivalent to the chlorine demand added to the desired chlorine
residual of 0.3 mg/L. A chlorine demand test can be performed using the Hach free chlorine test kit.
4.4.3.3 Tracer Study to Determine Contact Tank Efficiency
As part of the pilot study, the community has the opportunity to implement a tracer study to determine
the amount of short-circuiting in the existing reservoir at the start of chlorination. When chlorine is first
introduced into the system, the free chlorine concentration leaving the reservoir can be measured at
intervals until the concentration leaving the tank stabilizes. When chlorine is dosed at a constant ratio,
the time at which the free chlorine concentration reaches a steady value is the effective contact time, or
T10 of the tank. This study can result in a more accurate baffling factor value for the tank in Apatug as
well as for similar tanks being used in other communities in rural Ecuador.
4.4.3.4 Chlorine Residual and Bacteriological Growth Monitoring
Chlorine residual monitoring should be performed throughout the system as soon as chlorine dosing
begins. The Junta de Agua Potable of Apatug should assign an individual to perform and record the
chlorine residual monitoring four times per week during the course of the pilot study and during normal
maintenance of the system. Chlorine residual monitoring should be performed immediately after the
chlorine contact tank, at the north end of the community, and at a few key points throughout the
distribution system. Recommended sampling locations are indicated in Figure 88.
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Pg. 13
Bacteriological monitoring should be performed in conjunction with chlorine residual testing to assess
the effectiveness of the residual concentration in preventing bacterial growth. Bacteriological
monitoring is more expensive to perform, and it requires incubation of water samples at 35 °C (95 °F) for
24 hours. It is recommended that an outside party with access to an incubator and sterilized equipment
assist the community of Apatug during the water testing portion of the pilot study. Since testing for
coliforms is more expensive than chlorine residual testing, bacteriological monitoring should be
performed biweekly at test sites 3, 7, 8, and 10, as shown in Figure 8. Coliform tests should always be
performed in conjunction with chlorine residual testing so that a minimum chlorine residual
concentration to preclude bacterial growth in the system can be determined.
In addition to water testing, the Junta de Agua Potable should monitor the public receptivity of the
chlorination of drinking water, including the location and date of reports of taste concerns. The dosing
of sodium hypochlorite should be adjusted to maintain chlorine residuals of approximately 0.3 mg/L
throughout the system, or to a level that can be shown to prevent bacterial growth without major taste
concerns.
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Pg. 14
Figure 8. Proposed Test Sites (Sitios) for Chlorine Residual and Bacteriological Monitoring.
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Pg. 15
4.4.4 Timeline
The first step in the implementation of the pilot study is installation of the dosing pumps, including
additional pipes and valves, as well as the purchase and storage of sodium hypochlorite. A chlorine
demand test of the system can be completed as soon as the free chlorine test equipment is acquired. A
timeline for the pilot study is shown graphically in Figure 9.
1
2
3
•Obtain necessary equipment, includes pumps, valves, chlorine solution and storage tank, and
test kits.
•Install chlorine dosing system just before the existing reservoir.
•Implement the tracer study to determine the effective contact time obtained in the existing
reservoir.
4
•Test chlorine residual concentration four times per week.
•Test for bacterial coliforms two times per week.
•Monitor public acceptance of chlorination.
5
•Investigate electrolysis.
•Continue to monitor residual chlorine.
Six week duration
Figure 9. Pilot Study Timeline Summary
The tracer study to determine the baffling factor in the tank should be implemented when chlorine is
first dosed into the system, allowing the effective contact time of the existing reservoir to be adequately
measured.
Chlorine residual and bacteriological monitoring should be performed for the first six weeks in which the
chlorination system is operating. Chlorine residual should be measured at ten locations throughout the
community five days a week for six weeks. Coliforms should be monitored at four locations throughout
the community two days a week for six weeks, always in conjunction with a chlorine residual test.
Chlorine residual monitoring should continue regularly, even after completion of the pilot study.
Consistent residual monitoring will allow the community to determine an optimal chlorine dose for the
distribution system to ensure drinking water is disinfected without compromising taste. During the pilot
study, community receptivity and response to the chlorination system should be also closely monitored
and recorded by the Junta de Agua Potable.
May 2015
Pg. 16
The Junta de Agua Potable is encouraged to investigate the implementation of electrolysis in Apatug to
produce sodium hypochlorite for the community. In the event that electrolysis equipment is acquired,
the strength of the chlorine solution produced should be measured using the free chlorine testing kit.
4.5 Electrolysis
As a possible source for hypochlorite solution the team recommended that the community of Apatug
investigate the purchase of equipment for electrolysis. Electrolysis can be used to create a sodium
hypochlorite solution by running an electric current through a solution of salt water. There are several
advantages to using electrolysis to produce a hypochlorite solution in the community. First, electrolysis
is a more cost-effective way to chlorinate the drinking water distribution system, eliminating the need
for purchase, transportation, and excess storage of sodium hypochlorite solution. Secondly, producing
hypochlorite onsite will allow Apatug to make chlorine solutions for surrounding communities as well.
The electrolysis equipment should be housed in a building which already receives electricity. Electrolysis
is already being implemented in the community of Santiago de Quito which is about 60 km from Apatug.
In Santiago de Quito, a 1% sodium hypochlorite solution is produced. Currently, communities bring salt
to the clinic, and they can retrieve the hypochlorite solution the following day.
4.6. Potential Concerns
There are a number of issues which could provide problems for this pilot study. The first is the
acquisition of the pump. While the team has tested two common non-electric fluid-driven pumps, their
availability in Ecuador is uncertain. It may also be necessary to acquire, or translate, an instruction
manual in Spanish and/or Quichua for the community. A second issue which may arise is the installation
of these pumps in a shunt flow. A shunt flow is necessary to prevent the pump from being
overwhelmed, as the tested pumps are not rated for the 6.1 liters per second of flow which enter the
reservoir.
Another potential issue is the chlorine dose. The perception of chlorine is not good in rural Ecuador as
many believe it makes the water taste badly. For this reason, the application of chlorine must be done in
a delicate manner so as not to offend the community or render the water “undrinkable” in their
perception.
A final issue is the chlorine source. The chlorine solution that will be fed into the water source by the
pump will have to be mixed by community members. This system will require people who are
committed as well as knowledgeable so that the solution is mixed to the correct dose.
V. Conclusion
The ACE Team would like to thank Apatug and its Junta de Agua Potable for the opportunity to work
with such a wonderful, hospitable, welcoming community. The ACE Team believes that if the community
of Apatug implements the three year plan outlined in this report, the current water distribution system
will be able to sustain the community for twenty years including the projected growth over those twenty
years. The ACE Team hopes to keep in contact with Apatug and to be able to see their water system
improved and well kept.
May 2015
Pg. 17
AppendixL–ChlorinationPilotStudyTestKitsSpecificationSheets
L-1
L-2
L-3