Document text
Calhoun
iniQiuiic^iul Ar{hiv« of tilt Mil vdl Poii^roduiit School
Calhoun: The NPS Institutional Archive
□Space Repository
Theses and Dissertations
1. Thesis and Dissertation Collection, all items
2016-12
Analysis and design of a water purification
system for the West African Area of Operation
Ezedike, Jude C.
Monterey, California: Naval Postgraduate School
http://hdl.handle.net/10945/51690
This publication is a work of the U.S. Government as defined in Title 17, United
States Code, Section 101. Copyright protection is not available for this work in the
United States.
Downloaded from NPS Archive: Calhoun
DUDLEY
KNOX
LIBRARY
htt p://w ww. n ps. e du/l ib ra ry
Callwuo is the Naval Postgraduate School's public access digital repository for
research mate rials and institutiional publicatkios created by the NPS community.
Calhoun is named for Professor of Mathematics Guy K. Caftiouo, NPS's first
appointed — and published — schoteily author.
Dudley Knox Library / Naval Postgraduate School
411 Dyer Road / 1 Univefsity Circle
Monterey, California USA 93943
NAVAL
POSTGRADUATE
SCHOOL
MONTEREY, CALIFORNIA
THESIS
ANALYSIS AND DESIGN OF A WATER PURIFICATION
SYSTEM FOR THE WEST AFRICAN AREA OF
OPERATION
Thesis Advisor:
Co-Advisor:
Second Reader:
by
Jude C. Ezedike
December 2016
Ronald Giachetti
Ronald Carlson
Matthew Boensel
Approved for public release. Distribution is unlimited.
THIS PAGE INTENTIONALLY LEET BLANK
REPORT DOCUMENTATION PAGE
Form Approved 0MB
No. 0704-0188
Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing
instruction, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection
of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including
suggestions for reducing this burden, to Washington headquarters Services, Directorate for Information Operations and Reports, 1215
Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork
Reduction Project (0704-0188) Washington, DC 20503.
1. AGENCY USE ONLY 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED
(Leave blank) _ December 2016 _ Master’s thesis _
4. TITLE AND SUBTITLE
ANALYSIS AND DESIGN OF A WATER PURIFICATION SYSTEM FOR
THE WEST AFRICAN AREA OF OPERATION _
6. AUTHOR(S) Jude C. Ezedike
II. SUPPLEMENTARY NOTES The views expressed in this thesis are those of the author and do not reflect the
official policy or position of the Department of Defense or the U.S. Government. IRB number_N/A_.
13. ABSTRACT (maximum 200 words)
The borehole water system (BWS) in West Africa has capability gaps in the area of detection and
monitoring of chemical compounds, fdtration, and disinfection of potable water. As a result, there is not
enough potable water in West Africa to support a large-scale U.S. forces operation. This research focuses
on the analysis of BWS and its ability to deliver potable water to meet U.S. standards in West Africa. The
intent of this research is to design and test a feasible and cost-effective prototype of a purification system
to the BWS for improved capability.
This study uses a design-based and analytic research method with emphasis on basic systems
engineering process. The Pugh Matrix was used in the feasibility study to determine the alternative water-
purification system selection. The feasibility study confirmed that in terms of cost and operating
efficiency, the Modified Reverse Osmosis System (MROS) met all operational requirements. A prototype
model of the selected system was tested and evaluated to determine feasibility of the design. The prototype
test results showed that the water purification system performed effectively and efficiently in accordance
with the operational requirements. The water-purification system’s reliability was modeled and estimated
to show overall reliability of 0.9064.
16. PRICE CODE
NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89)
Prescribed by ANSI Std. 239-18
20. LIMITATION
OE ABSTRACT
15. NUMBER OE
PAGES
123
14. SUBJECT TERMS
borehole water system, capability gaps, functional analysis, functional requirements, improved
borehole water system, need analysis, operational analysis, operational concept, operational
model, operational and technical feasibility, prototype model, system reliability analysis
18. SECURITY
CLASSIEICATION OE THIS
PAGE
Unclassified
19. SECURITY
CLASSIEICATION OE
ABSTRACT
Unclassified
17. SECURITY
CLASSIEICATION OE
REPORT
Unclassified
12b. DISTRIBUTION CODE
12a. DISTRIBUTION / AVAILABILITY STATEMENT
Approved for public release. Distribution is unlimited.
7. PEREORMING ORGANIZATION NAME(S) AND ADDRESS(ES)
Naval Postgraduate School
9. SPONSORING /MONITORING AGENCY NAME(S) AND
ADDRESS(ES)
N/A
5. EUNDING NUMBERS
8. PEREORMING
ORGANIZATION REPORT
NUMBER
10. SPONSORING /
MONITORING AGENCY
REPORT NUMBER
1
THIS PAGE INTENTIONALLY LEET BLANK
11
Approved for public release. Distribution is unlimited.
ANALYSIS AND DESIGN OF A WATER PURIFICATION SYSTEM FOR THE
WEST AFRICAN AREA OF OPERATION
Jude C. Ezedike
Lieutenant, United States Navy
B.S., Florida A & M University, 2005
M.S., Embry Riddle Aeronautieal University, 2007
M.A., Webster University, 2014
Submitted in partial fulfillment of the
requirements for the degree of
MASTER OF SCIENCE IN SYSTEMS ENGINEERING
from the
NAVAL POSTGRADUATE SCHOOL
December 2016
Approved by: Ronald Giaehetti
Thesis Advisor
Ronald Carlson
Co-Advisor
Matthew Boensel
Seeond Reader
Ronald Giaehetti
Chair, Department of Systems Engineering
iii
THIS PAGE INTENTIONALLY LEET BLANK
IV
ABSTRACT
The borehole water system (BWS) in West Afriea has capability gaps in the area
of detection and monitoring of chemical compound, filtration, and disinfection of potable
water. As a result, there is not enough potable water in West Africa to support a large-
scale U.S. forces operation. This research focuses on the analysis of BWS and its ability
to deliver potable water to meet U.S. standards in West Africa. The intent of this research
is to design and test a feasible and cost-effective prototype of a purification system to the
BWS for improved capability.
This study uses a designed-based and analytic research method with emphasis on
basic systems engineering process. The Pugh Matrix was used in the feasibility study to
determine the alternative water-purification system selection. The feasibility study
confirmed that in terms of cost and operating efficiency, the Modified Reverse Osmosis
System (MROS) met all operational requirements. A prototype model of the selected
system was tested and evaluated to determine feasibility of the design. The prototype test
results showed that the water purification system performed effectively and efficiently in
accordance with the operational requirements. The water-purification system’s reliability
was modeled and estimated to show overall reliability of 0.9064.
V
THIS PAGE INTENTIONALLY LEET BLANK
VI
TABLE OF CONTENTS
I. INTRODUCTION.I
A. BACKGROUND.I
B. PROBLEM STATEMENT AND RESEARCH QUESTION.4
C. OBJECTIVES.4
D. BENEFIT OF THE STUDY.5
1. Benefit to U.S. Military.5
2. Benefit to Local Population.6
E. SCOPE, LIMITATIONS AND ASSUMPTIONS.6
F. METHODOLOGY AND APPROACH.7
G. ORGANIZATION OF THE STUDY.9
II. REVIEW OF RELEVANT LITERATURE.II
A. PRIMARY WATER SOURCES IN WEST AFRICA.II
1. Borehole Water System (BWS).II
2. Rain Water.II
3. River Water.13
B. REVIEW OF WATER PURIFICATION AND TREATMENT
TECHNOLOGIES.13
C. REVIEW OF WATER QUALITY IN WEST AFRICA.21
III. OPERATIONAL ANALYSIS AND USER NEEDS.27
A. NEEDS ANALYSIS.27
B. OPERATIONAL ANALYSIS.28
C. OPERATIONAL REQUIREMENTS.29
1. High-Level User Requirement.30
2. System Size.30
3. Operational Concept.30
4. Proposed Maintenance Concept.31
5. Environmental Factor.31
6. System Reliahility.32
D. FUNCTIONAL ANALYSIS.32
1. Functional Hierarchy.32
2. Description of the Water System Functions.34
3. Functional Flow Block Diagram.36
4. Timeline Analysis.40
E. LIST OF SYSTEM REQUIREMENTS.41
F. TECHNOLOGY FEASIBILITY.46
vii
1. Modified Reverse Osmosis System (MROS).47
2. Water Distillation System (WDS).47
3. Contracted Water Supplier (CWS).48
G. COST ANALYSIS OF THE WATER PURIFICATION
SYSTEM.51
IV. DETAIL DESIGN OF SYSTEM COMPONENTS.57
A. SYSTEM DESCRIPTION.57
1. Power System.58
2. Monitor/Detector System.59
3. Pump Systems.60
4. Pre-Filter Subsystem.61
5. Membrane Subsystem.62
6. Post-Filter Subsystem.64
7. Tank Subsystem.64
8. Disinfection System.65
B. WATER SAMPLING ANALYSIS.66
C. WATER PURIFICATION SYSTEM PHYSICAL MODEL.67
1. Model Development and Implementation.68
2. Operational Test and Evaluation.70
3. Pre-Water Treatment Test Analysis.71
4. OT&E Procedure.73
D. SYSTEM RELIABILITY ANALYSIS.77
1. System Overall Reliability Model.78
2. Fault-Tree Analysis.85
E. INTEROPERABILITY REQUIREMENTS.86
F. OPERATIONAL USE AND SYSTEM SUPPORT.88
V. CONCLUSION AND RECOMMENDATIONS.91
A. CONCLUSION.91
B. RECOMMENDATIONS FOR FURTHER STUDY.93
LIST OF REFERENCES.95
INITIAL DISTRIBUTION LIST
lOI
LIST OF FIGURES
Figure 1. Water Stress by Country. Souree: WRI (2012).4
Figure 2. Current Borehole Water System. Source: TWP (2016).5
Figure 3. The “V” Model of Systems Engineering. Adapted from Coolahan
(2012).8
Figure 4. Average Monthly Rainfall for Nigeria from 1990-2012. Source: The
World Bank Group (2016).12
Figure 5. Chemical and Physical Water Treatment Process and Example
Technologies. Source: WlPO (2012).14
Eigure 6. Eocal Water Treatment Using Chlorine Tablet. Source: WHO
(2013a).18
Eigure 7. Chlorination Treatment. Source: Eood and Agricultural Organization
of the United Nations (EAO) (1999).19
Eigure 8. Ozone Water Treatment System. Source: Eood and Agricultural
Organization of the United Nations (1999).20
Eigure 9. Schematic of the UV Water Treatment System. Source: World
Intellectual Property Organization (2012).21
Eigure 10. Simplified Needs and Opportunities Analysis Diagram. Adapted
from Coolahan (2012).28
Eigure 11. A Depiction of Operational Concept of the Water System.29
Eigure 12. Eunctional Hierarchy of the Water System (SV-4).33
Eigure 13. Water System EEBD.39
Eigure 14. Time Eine Analysis for the Water Purification Operation.41
Eigure 15. A Depiction of size and dimension of MROS.47
Eigure 16. Depiction of Vapor Compression Water Distillation System (VC
6000).48
Eigure 17. System Interface Diagram (SV-1).57
IX
Figure 18. Physical Decomposition Level One for the Water Purification
System.58
Figure 19. Physical Decomposition Level Two for the Power System.59
Figure 20. Physical Decomposition Level Two for the Monitor/Detector System.60
Figure 21. Physical Decomposition Level Two for the Pump System.61
Figure 22. Physical Decomposition Level Two for the Pre-Filter Assembly.62
Figure 23. Physical Decomposition Level Two for the Membrane Subsystem.63
Figure 24. Physical Decomposition Level Two for the Post Filter Subsystem.64
Figure 25. Physical Decomposition Level Two for the Storage Tanks System.65
Figure 26. Water Sampling Logic Diagram.67
Figure 27. Block Diagram of Water Purification Mode Prototype Model.68
Figure 28. Four Stage Prototype Model Integration.69
Figure 29. The Water Purification System Prototype Model Configuration.74
Figure 30. Water System Reliability Model.79
Figure 31. RBD of Non-potable tank, Rain water tank, Power, Pump, and
Monitor Systems.81
Figure 32. RBD of the Pre-filters.81
Figure 33. RBD of Membrane Elements.83
Figure 34. RBD of the Post-Filters.83
Figure 35. Fault Tree Analysis of the Water System.86
Figure 36. Interoperability Diagram.87
Figure 37. System Operational and Maintenance Flow. Adapted from
Blanchard and Fabrycky (2011).89
X
LIST OF TABLES
Table 1. Physical Methods for Water Treatment at the Household level.
Adapted from Sobsey (2002).15
Table 2. Chemical or Physical-Chemical Methods for Water Treatment at the
Household Level. Adapted from Sobsey (2002).16
Table 3. List of Water System Requirements.43
Tabled. Alternative Data.49
Table 5. System Selection Using Pugh Matrix.50
Tabled. Cost Breakdown of MROS.52
Table 7. Cost Analysis Summary of the MROS.53
Table 8. Cost-Breakdown of WDS.54
Table 9. Cost Analysis Summary of the WDS.55
Table 10. Cost-Breakdown of the CWS.56
Table 11. Cost Analysis Summary of the CWS.56
Table 12. Prototype Water Purification System Parts List.69
Table 13. OT&E Validation Checklist. Adapted from ESP Water Products
(2016).70
Table 14. Conditions for Operation of TEC Membrane. Adapted from ESP
Water Products (2016).71
Table 15. Tap Water Pre-Treatment Test Result.73
Table 16. Comparison of Pre and Post Tap Water Treatment Test Results.75
Table 17. Definition of Basic Reliability Terms. Adapted from Kumar et al.
(2006).78
XI
THIS PAGE INTENTIONALLY LEET BLANK
LIST OF ACRONYMS AND ABBREVIATIONS
ALUM
Hydrated Potassium Aluminum Sulfate
BWS
borehole water system
CBA
eost benefit analysis
ecu
eharge eontrol unit
COTS
eommereial-off-the-shelf
CWS
Contraeted Water Supplier
DAU
Defense Aequisition University
DNA
deoxyribonueleic aeid
DSMC
Defense System Management College
FAO
Pood and Agrieultural Organization of the United Nations
FFBD
Punetional Plow Bloek Diagram
GPD
gallons per day
lED
improvised explosive deviees
MCT
mean eorreetive maintenanee time
MCWSM
Marine Combat Water Survival Manual
MDT
maintenanee down time
MTBF
mean time between failure
MTBM
mean time between maintenanee
NACL
sodium ehloride
NASASEBOK
NASA Systems Engineering Handbook
NPV
Net Present Value
ov
Operational View
PH
Potential Hydrogen
PWS
pipeline water system
RO
Reverse Osmosis
SEBOK
Systems Engineering Handbook
SOE
Speeial Operations Porees
SOV
shut off valve
xiii
sv
System View
TBMED
Teehnieal Bulletin Medieal
TFC
thin film eomposite
TLA
Time Line Analysis
TPM
Teehnieal Performanee Measure
TWBG
The World Bank Group
TWP
The Water Projeet
UNC
University of North Carolina
UNICEF
United Nations Children Emergeney Fund
UV
Ultraviolet
WA
West Afriea
WDS
Water Distillation System
WHO
World Health Organization
WIPO
World Intelleetual Property Organization
WRI
World Resouree Institute
XIV
EXECUTIVE SUMMARY
Potable water is eritieally important in the battlefield. U.S. soldiers and eoalition
forees suffered from water-borne diseases such as skin abscesses, cellulitis, skin
infections, and diarrhea due to improperly treated water at five U.S. military sites in Iraq
(Margasak 2008; Moore 2011). Meanwhile, delivering bottled water to Iraq and
Afghanistan was very costly. The Lash (2011) report specifically indicates that it cost
$4.69 per gallon to deliver bottled water to soldiers operating in Afghanistan at a daily
demand of 5.3 gallons per Marine. Consequently, to supply water to 20,000 soldiers cost
about $491,140 a day in Afghanistan (Lash 2011).
In West Africa for example, the borehole water system (BWS), the source of
water supply mostly used, lacks capability of monitoring chemical compound, filtration,
and disinfection of potable water. As a result, there is not enough potable water to
support a large-scale U.S. forces operation if they ever operate in West Africa in the
future. Therefore, it is prudent to have a ready system for water purification and treatment
in the region given the threats of Boko Haram and other terrorist groups in Africa. The
literature survey showed that dependency on only natural filtration of ground water is not
sufficient for human consumption. The presence of metals and bacteria in the borehole
water systems indicate a need for water purification prior to use. Although the ground
water is naturally filtered in the aquifer, BWS being used is not equipped with the
monitoring system, which could dictate the presence of metals or contaminants in the
water.
This research focuses on the analysis of BWS in West Africa and its ability to
deliver potable water to meet the standard of U.S. forces operating in the area. The intent
of this research is to design and test a feasible and cost-effective prototype of a
purification system to the BWS that will improve its capability for the local population as
well as U.S. forces, if they ever operate there in the future. This thesis shows as a proof of
concept of the feasibility analysis and design of a water purification system for the
borehole water system for the U.S. forces operating in West Africa. The thesis argues
from a systems engineering perspective to the design of a water purification system to
XV
meet the eapability gaps of monitoring, filtering, and disinfeeting borehole water in West
Africa.
This study uses a designed-based and analytic research method with emphasis on
basic systems engineering processes to include descriptive models of the problem and
system. The water-purification system analysis and design is an iterative process, as
illustrated in the “V” model of Figure 3, in which each aspect of the design affects all
others. The first step in the process was to define the problem and conduct a user needs
analysis, analyze operational requirement, determine the operational concept, and
functional analysis of the proposed system. The Pugh Matrix was used in the feasibility
study to determine the water purification system to be selected for the BWS in West
Africa. A cost analysis of different water production alternatives proposed for the
modified system was modeled and the preferred system based on cost and benefit was
selected. From an innovative perspective of the water system, the operational and
feasibility study evaluated different feasible approaches to determine the most desirable
water purification system that met the capability gaps in the area of detecting and
monitoring of chemical compound, filtering, and disinfection of water. The analysis
confirmed that in terms of system cost, production rate, and operating efficiency.
Modified Reverse Osmosis System (MROS) met all requirements. By conducting cost-
benefit analysis of the water purification system, the MROS proved to be the most cost-
effective system compared other alternatives, such as Water Distillation System (WDS)
and Contracted Water Supplier (CWS).
The actual design process begins with the development of the functional
architecture using Lucid Chart and CORE modeling software. The functional architecture
enabled the tracing of the system needs as specified in operational requirements. A
composition and interactions of the water system was developed as a system interface
diagram, which annotates operational activities of each of the subsystem and external
components. The diagram shows components interactions with one another to enhance
the water purification process.
The author used the COTS components to build a prototype model to purify the
tap water from his kitchen. The Operational Test and Evaluation (OT&E) of the
prototype proved that the water system is both operationally and technieally feasible and
able to meet the high-level proposed requirements (monitor, fdter, purify, and store
water). Implementing the purifieation system to the BWS will prove that the water
purifieation system is effeetive and efficient. The objective of the prototype model was
met. The test and evaluation of the prototype provided feedback on how well the system
will perform in its operating environment and how to identify any problems. The system
performance was adequate and there were no corrective action or modifications required.
The prototype model for OT&E to this point proved that the system is expected to meet
user needs as specified.
Finally, the water purification system will use backup components to improve the
reliability of its critical components. The reliability analysis showed that MROS has high
reliability as demonstrated in Chapter IV. The author used the water purification system
aboard an FFG-7 frigate as a reference due to the system’s high reliability. The reliability
of the water purification system was based on the similar system aboard an FFG-7
frigate. The water system component reliability ranges from 0.97 to 0.99. Based on these
reliability values, the author estimated the overall reliability of the water system to be
0.9064. This means that the probability that the water purification system will accomplish
its operational tasks in a satisfactory manner for a given period is 90%.
List of References
Fash, Fred. 2011. “Marines Take Steps to Avoid Costly Bottled Water Resupply.”
National Defense, May 4.
http://www.nationaldefensemagazine.org/archive/2011/may/pages/marinestakeste
pstoavoidcostlybottledwaterresupply.aspx.
Margasak, Farry. 2008. “Water Reportedly Sickened U.S. Troops in Iraq.” USA Today,
March 9. http://usatoday30.usatoday.eom/news/world/iraq/2008-03-09-
water_N.htm.
Moore, James. 2011. “The U.S. Military’s Reliance on Bottled Water During Military
Operations.” M.S. thesis. National Defense University, Joint Advanced
Warfighting School, Norfolk, VA.
xvii
THIS PAGE INTENTIONALLY LEET BLANK
ACKNOWLEDGMENTS
First, I thank the Almighty God for this exceptional experience as a student at the
prestigious Naval Postgraduate School in Monterey, California. I wish to tha nk several
individuals who have continuously supported me throughout this entire adventure. I
would like to express my gratitude to Professor Barbara Berlitz for her review of this
thesis readability from a non-engineer perspective.
With utmost appreciation, I would like to thank my thesis advisors. Dr. Ronald
Giachetti and CAPT. Ronald Carlson (Ret) for their guidance, support, and
encouragement throughout this process. I sincerely thank Professor Matthew Boensel for
not only his support as second reader but also for his guidance throughout this whole
process.
Finally, I would specifically thank my beloved wife, Chinenye O. Ezedike, and
children, Mmesomachi and Chidiebube, for their support, patience, and prayers
throughout this work and my studies at Naval Postgraduate School. I must admit that
without them, this task would not have happened. Thank you very much!
XIX
THIS PAGE INTENTIONALLY LEET BLANK
XX
I.
INTRODUCTION
This chapter provides the background information on potable water and some
relevant effects of contaminated water on humans. The chapter discusses the challenges
supply and distribution of potable water posed to the United States forees during
Operations Iraqi Freedom and Enduring Freedom. Given the current threats in the West
African region, this chapter discusses the reasons there is need for a high quality water
system for U.S. forees that will operate in West Africa in the future.
A. BACKGROUND
Potable water is eritically important in the battlefield. During Operation Iraqi
Freedom for example, United States troops suffered from water-borne diseases due to
improperly treated water. Soldiers who were deployed to Iraq experienced different kinds
of skin diseases sueh as cellulitis, skin infections and abscesses, and diarrhea after using
diseolored water (Margasak 2008). There were instances when the quality of water that
was provided to the troops by eontractors did not meet the field water sanitary standards
as specified in the Department of Army, Teehnical Bulletin (Medical) 577 (Granetto
2008). Additionally, the water used for laundry and personal hygiene did not meet safety
standards under military regulations. As a result, the soldiers were in danger of harmful
exposure to diseases through bodily cuts, wounds, eyes, nose, and mouth (Margasak
2008; Moore 2011).
The water problems encountered by the U.S. troops during Operations Enduring
Freedom and Iraqi Freedom triggered researeh at the University of North Carolina.
Aecording to University of North Carolina (UNC) Global website (Gillings Sehool of
Global Public Health 2015), “bad water can slow down and compromise a mission,
hitting every man in the field. This beeomes espeeially dangerous for troops in the
Special Operation Forees (SOF) who are often operating behind enemy lines on missions
where they have to be extremely mobile, quiek and discreet.” The Gillings artiele
explains that in a situation where small teams of troops are on a mission, troops rely on
either bottled water or other water bodies that may be purified along their way in the area
1
of operation. That article elaborates that the small purification unit used by soldiers has
its disadvantages because they are limited in their ability to eliminate all microbial
threats. Soldiers also ingest harmful chemical compounds and are unable to eliminate
them. The Gillings article tells of troops in Iraq and Afghanistan that encountered
chemicals in the naturally available water such as carcinogens, lead, cyanide, arsenic and
mercury. Work is in progress to create a system that will detect harmful chemical and
microorganisms’ presence in the water and remove them (Gillings School of Global
Public Health 2015).
Establishing a reliable, safe protocol for the elimination of these chemicals
will aid manufacturers and developers creating current and next generation
iterations of these units. It will also greatly help the military in their
evaluation of these units during the procurement process, which can save
lives and potentially tens of millions of dollars. (Gillings School of Global
Public Health 2015, 2)
In Afghanistan, bottled water became the preferred option for U.S. Marines
because it was more convenient and tasted better than the purified river waters (Lash
2011). Since there was no central recycling facility, waste generated by water bottles
were burned in pits located in the center of bases creating toxic emissions that are
harmful to the troops (Lash 2011). Bottled water is capable of supporting bacterial
growth when it is not stored in a cool-dry and well ventilated area (Lash 2011).
According to Lash (2011), delivering bottled water to the troops in Afghanistan
was costly and created security problems by exposing the convoy needed to truck water
to improvised explosive devices (lED). The river water in Afghanistan has both
microbiological contaminants and chemical compounds, which required treatment before
consumption. Additionally, ground water supply was scarce in Afghanistan due to limited
rainfall. According to the war reports, it was estimated that U.S. forces, foreign
government officials and aid workers in Afghanistan consume bottled water at the cost of
$100 million annually (Lash 2011). The Marine Combat Water Survival Manual
(MCWSM) (2003) requires each Marine to consume at least 2.6 gallons of water daily to
remain healthy while operating in hot environment. The Lash (2011) report specifically
indicates that the cost of shipping bottled water to the soldiers in Afghanistan was about
2
$4.69 per gallon with daily demand of 5.3 gallons per Marine daily for eonsumption and
hygiene. The supply of water to 20,000 troops for example, eosts about $497,140 a day in
Afghanistan (Lash 2011).
The World Resouree Institute (WRI) (2016) prediets that over one billion people
on Earth live in water-scaree regions, and about 3.5 billion eould have water searcity by
the year 2025. Figure 1 illustrates the areas in the world of the predieted water stress by
the year 2040. As described by Maddocks, Young, and Reig (2015, 3), “businesses,
farms, and communities in these countries in particular may be more vulnerable to
scarcity than they are today.” Many of the high stress regions are where the U.S. military
might operate in the future.
Although there are no U.S. ground forces operating in West Africa now, it is
prudent to have a ready system for water purification and treatment in the region given
the current threat of Boko Haram and other terrorist groups in Africa. The West African
region lacks high quality water system, similar to many other third world regions. United
States forces would need cost effective and reliable high quality water system while
operating in West Africa and other third world regions.
Potable water contamination and shortage have continued to pose a great threat in
the West African region. In West African rural areas today, the common source of water
for human consumption comes from rivers, rainfall, and ground water. The individuals
who can afford it acquire the borehole water system (BWS), but the middle class and the
poor depend on rainfall and river water. Places where rainfall is rare utilize river water as
the source of drinking water. The users do not have the capability of filtering the river
water sources before use.
3
ratio of withdrawals
to supply
Lo»v(- 10^!
■ Low to mahunil 10-20%)
■ Medium 10 high (20-40%)
■ High,40m)
■ E»*Jwnety1»o^( -80%)
Figure 1. Water Stress by Countiy. Souree: WRI (2012).
B. PROBLEM STATEMENT AND RESEARCH QUESTION
The current BWS system in West Africa lacks capability of monitoring chemical
compound, filtration, and disinfection of potable water. As a result, there is not enough
potable water in West Africa to support a large-scale U.S. forces operation. This thesis
addresses the following research questions:
(1) What modifications need to be made to the existing West African borehole
water system (BWS) to make potable water?
(2) What water purification system can be incorporated with BWS to provide
cost-effective and safe water to U.S. forces operating in West Africa?
(3) Would the water purification system be operationally feasible, technically
feasible, and cost-effective for U.S. forces operating in West Africa?
C. OBJECTIVES
This research focuses on the analysis of BWS in West Africa and its ability to
deliver potable water to meet the standard of U.S. forces operating in the area. Additional
analysis and design will be conducted to determine if an off-the-shelf purification system
could be incorporated to the existing water system. The intent of this research is to design
and test a feasible and cost effective prototype of a purification system to the BWS that
4
will improve its capability for the local population as well as U.S. forces, if they ever
operate there in the future. Figure 2 shows the current borehole water system attached
with a hand pump. The system utilizes natural aquifer filtration and does not have any
purification system.
GU-
Figure 2. Current Borehole Water System. Source: TWP (2016).
D. BENEFIT OF THE STUDY
There are benefits for both future U.S. military operations in West Africa as well
as the local population.
1. Benefit to U.S. Military
The benefits of the study have potential to reduce costs over baseline systems in
use now, improve safer drinking water, eliminate lED attacks during water transportation
process, and reduce cost savings in recycling used water bottles.
• Adequate water sources in West Africa will be cost effective and reduces
the use of bottled water while in theater. As mentioned earlier, the cost of
bottled water once transported can reach as high as $4.69 per gallon.
5
Additionally, there is no eentral recyeling faeility in West Africa. The
water system would be beneficial to U.S. forces by reducing the
acquisition and transportation of bottled water and eliminate the need of
central recycling facilities to recycle used bottles in West Africa. Troops’
dependency on bottled water during extended military operations may
interfere with the ability to apply operational design elements and could
limit options in all phases of any military campaign. (Moore 2010)
• The water system is more likely to be instituted at every operating base
due to its cost benefit in West African Area of Operation. The use of the
system would eliminate or reduce vulnerability of Improvised Explosive
Device (lED) attacks to convoys during the water transportation process.
The system has performance characteristics, which makes it low cost, low
maintenance, affordable, and will not require continuous electricity to
operate. The water system can be implemented or sold to other third world
countries that may have similar water issues as in West Africa.
2. Benefit to Local Population
The water system will reduce communicable diseases, improve industrial needs,
and provide safe water to the local population.
• A quality water system in West African region will reduce the risk of
various waterborne diseases that have posed threat to the region. The
system will improve the quality of drinking water in West African region
and reduce the risk of consuming contaminated water.
• Industries that utilize water on a daily basis often frowns to invest in a
region where potable water is not adequate. The water system would be
beneficial to investors in the pursuit of business opportunities in the area.
• The system will provide the local populations of West Africa with safer
water and eliminate the need for river water. With the availability of
purified water in the area, those who depend on rainwater will no longer
trek long distances to obtain water in the river during dry season.
E. SCOPE, LIMITATIONS AND ASSUMPTIONS
The research scope is to analyze and design a purification system for the existing
BWS that have capabilities to monitor/detect, filter, and disinfect potable water. The
research encompasses the preliminary, conceptual and detailed design of the system and
does not involve the developmental stage of the system.
6
The water regulations and laws that eurrently govern eaeh West Afriean eountry
are in effeet and would be adhered to. A new method of drilling borehole water system is
not introduced and the procedures followed by the drillers are not changed. The current
state of the water systems in West Africa will not affect the research.
The following is a list of assumptions that were made for the analysis and
modification of the current water system;
• The borehole water and well system drilling procedures and flushing
mechanisms will not change.
• The current borehole water system (BWS) construction and installed
equipment to enable its operability will not change.
• The quality of borehole water will be maintained in accordance with field
water sanitary standards as specified in Department of Army, Technical
Bulletin (Medical) 577, “Sanitary Control and Surveillance of Field Water
Supplies.”
• Chemical compounds in the soil may flow into the groundwater causing
heavy metal contamination.
West Africa is a tropical rain forest region. Therefore, nitrates in the soil
could leach and enter in the ground water due to heavy rainfall.
F. METHODOLOGY AND APPROACH
This study uses a designed-based and analytic research method with emphasis on
basic systems engineering processes to include descriptive models of the problem and
system. The water system design is an iterative process as illustrated in the “V” model
depicted in Figure 3, in which each aspect of the design affects all others. The following
systems engineering process as described by Blanchard and Fabrycky (2011) was used
during this study:
Identify and translate the problem into a definition of need for a system that will
provide the capabilities to purify borehole water.
• Identify operational analysis using architecting in response to the identify
and document user need.
• Develop system operational requirements, functional analysis and allocate
system functions to components
7
• Conduct feasibility studies leading to the definition of purification system
technology for system design.
• Aecomplish the system-level verification of components and subsystems
• Perform test and evaluation of prototype model and estimate system
reliability.
• Develop maintenance concept for the sustaining support of the system
throughout its planned life cycle.
Figure 3. The “V” Model of Systems Engineering.
Adapted from Coolahan (2012).
The Pugh Matrix was used in the feasibility study to determine the water
purifieation system to be selected for the BWS in West Afriea. A cost analysis of
different water purifieation alternatives proposed for the modified system was modeled
and the preferred system based on cost and benefit was selected. A prototype model built
by the use of commercial of-the-shelf components was tested and evaluated to determine
the feasibility of the design. The test results were evaluated to ensure proper
compatibility and integration with other external components of the system. The
prototype was validated to provide assurance that it performed effectively and efficiently
in aecordanee with the requirements.
8
Furthermore, the Model-Based Systems Engineering tool (MBSE), CORE, and
Eucid Chart software were used to develop the functional architecture of the water
purification system. CORE modeling software was used to model system requirements,
and then translate the system requirements to the established functional requirements of
the water system. This process was used to produce a functional architecture, which
defined the logical flow and performance characteristics of the water system. Erom
functional requirements, each function was allocated to physical components. Using
CORE, a Eunctional Elow Block Diagram (EEBD) was developed to show system
interface with the functions and sub-functions in order to give an overall view of the
system’s relationship with the external components. Eucid Chart modeling software was
used to create the operational view, systems architecture, and physical decomposition of
the system to show its operational analysis. Einally, the reliability and interoperability of
the water system was modeled and calculated to illustrate the overall reliability and to
show interfaces with its operational environment.
G. ORGANIZATION OF THE STUDY
This thesis consists of five chapters. Chapter II discusses the review of water sources
in West Africa, water system technologies and review of water quality in West Africa.
Additionally, this chapter presents scholarly tests, evaluation, and analysis of the BWS to
enhance proper purification and treatment for human consumption. Chapter III presents the
operational analysis and user needs, and discusses the needs analysis, operational
requirements, operational analysis, functional analysis, system technical requirements
specifications, proposed maintenance concept, operational and technical feasibility study, and
economic analysis. The chapter also includes the functional hierarchy, description of
functions, functional flow block diagram, and timeline analysis. Chapter IV discusses the
detail design of the components, system description and physical architecture, water system
operational model, operational test and evaluation, system reliability analysis, water-
sampling model, interoperability requirements, operational use and system support. Chapter
V provides conclusions and recommendations.
9
THIS PAGE INTENTIONALLY LEET BLANK
10
II. REVIEW OE RELEVANT LITERATURE
The literature review has three seetions. The first is a review of primary water
sourees in West Africa. The second section is an overview of the water system
purification and treatment technologies and their importance to this study. The third
section is a review of water quality study in West Africa.
A. PRIMARY WATER SOURCES IN WEST AFRICA
This section discusses the three primary sources of water in West Africa and their
advantages and disadvantages in this research.
1. Borehole Water System (BWS)
Ground water is the water found under the surface of the earth and is the primary
source of springs, wells, and borehole water. Borehole water is never completely pure. Its
quality varies depending on the geological conditions of the soil through which the
ground water flows (Ukpong and Okon 2013). A borehole is a hydraulic structure that
enables the withdrawal of water from an aquifer. The current BWS in West Africa
utilizes natural aquifer filtration. It is not incorporated with filtration, monitoring, and
disinfection systems. In Nigeria for example, during borehole construction, the initial
dirty ground water is continuously flushed until the pure and clear water is obtained.
However, the application of weedicides, pesticides, and liquid waste introduce chemical
compounds into the ground. Nitrates in the soil that leached and entered into the
groundwater due to heavy rainfall is the primary disadvantage of borehole water system.
This water condition should be remediated before the water is used.
2. Rain Water
Africans obtain rainwater, the purest water source, through roof-based rainwater
harvesting. West Africans use underground water tanks as a means of harvesting
rainwater. One may use rain gutters attached to the roof, which are routed to the
underground tank and drums to collect the rainwater. There are risks that the rainwater
may be contaminated when stored in the underground or storage tanks if not treated.
11
According to Balogun et al. (2016), the rainwater that is collected depends on monthly
precipitation, roofing material and the cleanliness of the roof. Further, the quality of the
rainwater harvested is in accordance with type of roofing materials, atmospheric pollution
level, container size, and catchment characteristics. Balogun et al. (2016) explained in
their report that rainfall in Nigeria varies and ranges from 24% to 39% for the season and
26% to 41% from April to October.
In West Africa, dry season months are from November through April as
illustrated in Figure 4. During these months, there is limited rainfall and irrigation is the
only way farmers supply water to their crops. The dry season in Nigeria shows an
average rainfall of 1.63mm per year with a range of 1.19 to 2.27mm per year (Balogun et
al. 2016). The rainy season occurs from May to October each year and records a mean of
1.37mm per year with a range of 0.20 to 2.28mm per year (Balogun et al. 2016).
Household water harvesting is able “to meet 27.51 to 54.91% of non-potable household
water demand as well as 78.34 to 156.38% of household potable water demand for a six-
member household” (Balogun et al. 2016, 19). Due to dry season between the month of
October and May, rainwater source is limited and scarce during this period. This is the
main disadvantage of water users who depend on rainwater.
E
E
"m
««-
c
75
Qd
300
200
100
0
Jan
Figure 4.
Mar May Jul Sep Nov
Average Monthly Rainfall for Nigeria from 1990-2012.
Source; The World Bank Group (2016).
12
3.
River Water
While people obtain pure and clear borehole water and rainwater from their
sources, river water lacks purity and often contains debris. Surface water is not safe for
drinking unless bacteria, viruses, parasites, and protozoa are removed from it.
Purification of river water is not cost effective as it may require constant replacement of
the filter elements. Purification of surface water will also consume energy during the
purification process. Surface water is often polluted with industrial waste and substances
such as insecticides, pesticides, fertilizer, and soil erosion. Heavy metals such as acid
rain, salt, silt, and mercury may enter water bodies through rain erosion. Because of these
disadvantages, river water is not cost effective to purify for human consumption in West
Africa.
United Nations Children’s Emergency Fund (UNICEF) (2013) reported that over
2,000 children under the age of five die every day from diarrheal diseases. It is estimated
that of these, over 1,800 deaths are due to bad water, improper sanitation and hygiene.
The literature survey revealed that surface water in West Africa is contaminated and is
the main source typhoid, cholera, dysentery and hepatitis. Eack of water treatment causes
the growth of microorganisms in the water distribution system (WHO 2014). A modified
water system with treatment subsystem to improve the quality of drinking water in the
West African region is needed. A water purification system would be the ideal system in
the reduction of the water borne diseases in the region. This system will contribute
immensely in reducing diarrheal disease among children in West Africa.
B. REVIEW OF WATER PURIFICATION AND TREATMENT
TECHNOLOGIES
Water treatment is the process of making water quality acceptable for drinking,
industrial use, irrigation, river flow maintenance and other uses. Global inventions in the
area of water treatment promise reduced investment and operational costs for improved
water systems (WIPO 2012). According to WIPO (2012, 8), “Patent-based analyses can
identify the emerging technologies, players and value chains associated with next
generation water treatment technologies which, if deployed at mass scale, can rapidly
13
improve experience globally, lead to further innovation and take the technologies down
the cost curve.” Figure 5 shows water treatment technologies for physical and chemical
water treatment processes indicating the vast number of technologies that are currently
being used all over the world. The WHO (2011) report evaluated candidate technologies
for treatment of house water supply such as improvement of microbial quality and
reduction of waterborne disease.
media sand
softening pefopitation
cation exchange
anion exchange.. exchange
hydrogen zeo lit e softening
demineralisation
adsorption i
addition of add
addition of base
sodium inhibitor corrosion inhibitors
filtralion
membrane
nanoflitration
microfiltration
' ultrafiltration
physical treatments -
reverse osmosrs
coagulation/tlocculaticin
settling/flotation
low temperature
distillation
heal treatment evaporation msf
MED
water treatment
technologies
r - chemical treatments
I disinfection
; ajr treat ment
" deaeration
radiabon JW
, acoustic sound
electrodeionisation
ozone
KMn04■
addition of halogens |
addition of oxidants
capacitive d eionisalion
Figure 5. Chemical and Physical Water Treatment Process and Example
Technologies. Source: WIPO (2012).
Water treatment technologies are divided into physical and chemical treatment
methods. Physical water treatment methods are boiling, heating (fuel and solar), settling,
filtering, and ultraviolet (UV) radiation. Water chemical treatment methods are
comprised of Coagulation-Flocculation and precipitation, adsorption, ion exchange and
chemical disinfection (WHO 2011). Tables 1 and 2 present the different water treatment
methods including their availability and practicality, technical difficulty, cost, and
microbial efficacy. Currently, people who live in the rural areas of West Africa utilize a
combination of alternative filtration and chemical treatment methods to treat water prior
to consumption. Such methods are the use of locally produced alum or Potassium
14
Aluminum Sulfate (Potassium alum). Alum is added to the water in order to allow the
sediments to settle at the bottom of the water container. The water is then filtered through
cloth and boiled prior to consumption. According to Sobsey (2002, 36), “alum
coagulation and precipitation remove turbidity and other visible contaminants from the
water at the household level.” This traditional method has been practiced in many parts of
the world for centuries. Chemical coagulation, flocculation and precipitation are another
chemical method of water treatment that has been practiced since ancient times. WHO
(2011, 1) explained that, “Coagulation or precipitation is any device or method
employing a natural or manufactured coagulant or precipitant to coagulate and/or
precipitate suspended particles, including microbes, to enhance their sedimentation.”
Sobsey explained that this method “enhances the removal of colloidal particles by
destabilizing them, chemically precipitating them and accumulating the precipitated
material into larger particles that can be removed by gravity settling or filtering.” (Sobsey
2002, 3). This process enables the reduction microorganisms and dissolved solids in the
water (Sobsey 2002).
Table 1. Physical Methods for Water Treatment at the Household level.
Adapted from Sobsey (2002).
Method
Availability
and
Practicality
Technical
Difficulty
Cost
Microbial
Efficacy
Boiling or Heating with
Fuel
Varies
Low-Moderate
Varies
High
Exposure to Sunlight
High
Low-Moderate
Low
Moderate
UV Irradiation (Lamps)
Varies
Low-Moderate
Moderate-
High
High
Plain Sedimentation
High
Low
Low
Low
Filtration
Varies
Low-Moderate
Varies
Varies
Aeration
Moderate
Low
Low
Low
15
Table 2. Chemical or Physical-Chemical Methods for Water Treatment at the Household Level.
Adapted from Sobsey (2002).
Method
Availability and
Practicality
Technical Difficulty
Cost
Microbial Efficacy
Coagulation-Flocculation
or Precipitation
Moderate
Moderate
Varies
Varies
Adsorption (Charcoal,
carbon, clay, etc.)
High to Moderate
Low-Moderate
Varies
Varies with Adsorbent
Ion Exchange
Low to Moderate
Moderate to High
Usually
High
Low to Moderate
Chlorination
High to Moderate
Low to Moderate
Moderate
High
Ozonation
Low
High
High
High
Chlorine Dioxide
Low
Varies
High
High
lodination (elemental,
salt or resin)
Low
Moderate to High
High
High
Acid or Base Treatment
with citrus Juice,
hydroxide salts, etc.
High
Low
Varies
Varies
Silver or Copper
High
Low
Low
Low
Combined Systems:
Chemical Coagulation-
Flocculation, filtration,
chemical disinfection
Low to Moderate
Moderate to High
High
High
16
Similarly, filtration is another ancient method that is used to remove particles and
some microbes from the water. Filtration enables the removal of microbes; however, the
effectiveness of this method depends on the presence of microbe in the water and the
filter quality that is being used (Sobsey 2002). As described by WHO (2011), the “point-
of-use water filtration technologies are cloth, fiber filters, membrane filters, porous
ceramic filters, carbon filters, and composite filters.” Membrane filtration is used to
remove suspended and dissolved solids such as salt and marine microorganisms. The
membrane filtration system technology is expensive and used in developed countries.
Reverse Osmosis is a type membrane filtration used as pre-treatment of feed water prior
to commencing a desalination process. Water treatment technologies are important for
desalination technology, especially in the area where rain and ground water are scarce
(WIPO 2012). Aboard merchant and naval ships, desalination technology is useful in
water production for the crew.
In West Africa, people use locally made filtration cloth to purify water obtained
from the river. This traditional method only removes some microbes in the water but does
not remove all impurities to make the water safe for human consumption. Figure 6
illustrates the WHO guidance on emergency treatment of drinking water at the point of
use. The illustration shows how to treat water with chlorine tablets.
Aeration is one of the alternatives of water treatment. In this method, water has
close contact with air, increasing its oxygen content. This method involves shaking the
water in a container rapidly for about five minutes, let it for 30 minutes, and this allows
the suspended particles to settle on the bottom (WHO 2013a). Aeration of water
introduces oxygen, which causes chemical reaction and contributes to the reduction of
microorganisms in the water (Sobsey 2002). It is not proven that aeration alone reduce
microbes. Further research will need to be conducted to determine if the inactivation of
microbes in water involve a combination of other agents.
17
Figure 6. Local Water Treatment Using Chlorine Tablet.
Source: WHO (2013a).
Chemical water treatment is the most effective method to destroy dissolved solids
and microorganisms in drinking water (Sobsey 2002). The use of chlorine as an effective
disinfectant water agent that was introduced in the late 19* and early 20* centuries
(Sobsey 2002). Figure 7 shows a chlorination treatment system where fresh or seawater is
introduced into the system and pumped to the hypochlorite solution where the mixture is
cycled. The solution inactivates greater than 99.99% of eccentric bacteria and viruses
(Sobsey 2002). When the quantity of chlorine added to the water is sufficiently large to
ensure that it is not all reduced or combined, a portion of it will remain free in the water
(FAO 2011). It is evident that free chlorine effectively inactivates waterborne microbes;
however, its use in water treatment reduces the risks of waterborne diseases (FAO 2011).
18
By-pass valve
Figure 7. Chlorination Treatment. Souree: Food and Agrieultural
Organization of the United Nations (FAO) (1999).
Sobsey (2002, 47) shows that “Ozone is a strong oxidant eapable of rapidly and
extensively inactivating a variety of waterborne pathogens,” which includes chlorine-
resistant pathogens. The ozone method of water purification is suitable for community.
Ozone is not a good candidate for small, individualized household water treatment due to
control of each serving is too costly. The system requires a reliable source of electrical
power. Figure 8 presents an ozone treatment system. The requirement for the system is a
supply of oxygen and operators. Unfiltered raw water is pumped into the system where
two carbon fdters fdter the water. Ozone is now produced by sending pure oxygen
through an ozone generator and bubbles it through “a gas diffuser at the bottom of an
absorption column in a direction opposite to the flow of raw water” (FAO 2011, 10). This
process reduces turbidity of water by breaking down organic constituents.
19
Unfiltered
raw water Ozaiic Generator
Filtered
Water
Figure 8. Ozone Water Treatment System. Souree; Food and Agrieultural
Organization of the United Nations (1999).
Another produetive and effieient water treatment teehnology is ultraviolet
irradiation, whieh was introdueed in the late 1800s. The system uses short wavelength in
the range of 100-280nm UV radiation. This destroys the nucleie aeids in the organisms,
disrupting their Deoxyribonucleie Aeid (DNA), removing their reproduetive eapability
(WIPO 2012). Ultraviolet irradiation has the eapability to inaetivate greater than 99.99%
waterborne chlorine-protozoans at low doses of less than lOMJ/cm^ (Sobsey 2002). The
system is very “effective for inactivating waterborne pathogens, simple to apply at the
household and community levels, and relatively low cost while not requiring the use of
chemicals or creating taste, odors or toxic chemical by-products” (Sobsey 2002, 20). Figure 9
shows example of the UV water treatment system. The system is incorporated with low-
pressure vapor lamp or a medium pressure UV lamp. The function of the low-pressure
mercury vapor lamp is to produce high-energy UV radiation at 40% efficiency while the
medium pressure lamp produces a polychromatic output at 12% efficiency (WIPO 2012).
While this system uses UV radiation to inactivate microorganism and dissolved solids in the
water, the lamp meets the water. It is enclosed in a quartz sleeve located inside a chamber
where the water flows through and exit at the out subsystem (WIPO 2012).
20
IMLEX DisiisiFECXiaiM cmambeir
a UXLEX
( Disiisifecxed waxer)
Figure 9. Schematic of the UV Water Treatment System. Source: World
Intellectual Property Organization (2012).
C. REVIEW OF WATER QUALITY IN WEST AFRICA
This literature review explores water qualities in West Africa to identify and
address the capability gaps to fill. In Nigeria for example, pipeline water system (PWS)
was being used but are now inoperable and are not channeled to the villages. In the
developed cities where PWS are used, water service is not consistent due to the growing
urban population. As a result, potable water services are not provided to these areas due
to rapidly growing demand for services (Chitonge 2014). People in the urban and rural
areas have turned to borehole water system as the main source of water. Chitonge (2014)
argued that in order to prevent crisis of access to water, resources used to maintain PWS
network to the poorly served area should be a priority in many of the African countries.
According to a study conducted by Uneze, Tajudeen, and Iwela (2012) on the
“cost-effectiveness and benefit-cost analysis of some water interventions in Nigeria, with
emphasis on pipeline and borehole (hand pump) water supply” systems, the borehole
water system was found to be more cost-effective than the pipeline water system (PWS).
The BWS is more efficient and sustainable compared to the PWS.
21
A borehole is defined as a hydraulie strueture that enables the withdrawal of water
from an aquifer. The eurrent BWS utilizes natural aquifer filtration. Currently, it is not
incorporated with filtration, monitoring, and disinfectant systems. World Health
Organization (2013b) evaluated that high concentrations of chemical compounds such as
arsenic and fluoride, which originate from natural sources affect millions of people in the
world. This is the reason a dependency on only the natural filtration of the borehole water
system is not adequate for human consumption.
In order to ensure that the BWS is suitable for drinking, its quality must be
evaluated by collecting samples and analyze them. When the water does not meet
requirements, proper remediation will be necessary (Houlihan and Lucia 1999). Once the
purification components are incorporated to the BWS, it will not only be used in the West
African area of operation but will be available in other third world countries where U.S.
troops may operate.
In Nigeria, Adelekan (2010) assessed the quality of water supply from different
wells in order to ascertain the contamination that exists in the well water in Ogun State.
Water samples collected were checked for odor, color, and taste. The samples were
analyzed for PH, total dissolved solids, total hardness, total chlorine, free chlorine and,
other chemical compounds. The study concluded that he PH values of the samples tested
were not within the WHO recommended range of 6.5-8.5 for drinking water. Meanwhile,
the WHO guidelines were met for total solids and hardness of the water (Adelekan 2010).
These findings were helpful towards the design and analysis for a water purification
system that will combat the presence of these metal compounds in the water.
Jeje and Oladepo (2014) obtained similar results in their investigation of the
presence of heavy metals in boreholes and wells in Osun State Nigeria. A sample of 41
functional wells and nine borehole systems were sampled, and the results indicated
concentrations of the metals such as zinc, lead, and manganese in the water. The presence
of these metals in the water met the WHO permissible limits with an average values of
0.02mg/l, 0.14mg/l, and 0.03mg/l. However, the value of chromium was high at 6.5mg/l.
The values of the presence of the metals in the water showed that the water was not
contaminated and was good for human consumption with the exception of the higher
22
chromium values. In the eonclusion of his report, Jeje and Oladepo (2014) emphasized
that proper filtration and treatment of the water was needed prior to delivery to the
eonsumers. Unlike Jeje and Oladepo (2014), Kawa et al. (2016) analyzed 10 well water
systems for 18 quality parameters in Kukua Chiefdom of Bo District, Sierra Leone. The
result of this test eoneluded that there were metal oxides in the water and the WHO
standard was not met. With water purifieation system, the presenee of these metals in the
water would be monitored and treated before water usage.
In West Afriean eountries, there is seareity of water supply both in the rural and
urban areas. In Nigeria for example, water supply in the urban area has diminished, and
the quality of water is questionable (Ezeabasili, Anike, and Okonkwo 2014). As a result,
many households have invested in private borehole water system as a means of avoiding
the intermittent water supply from the publie PWS. Aeeording to Ezeabasili, Anike, and
Okonkwo (2014), the intermittent water supply in the urban areas is due to laek of
operation and maintenanee of the PWS. However, this study would draw on the work of
Ukpong and Okon (2013) in the “Comparative Analysis of Public and Private Borehole
Water Supply Sourees in Uruan Eocal Government Area of Akwa Ibom State Nigeria.”
Ukpong and Okon (2013) used the standard analytieal teehniques and instruments to
study 10 randomly seleeted private and three funetional publie boreholes in the area.
Results showed presenee of eight baeteria speeies, whieh were isolated and identified.
The statistieal analysis showed differenee in water quality of both boreholes. With the
results, reeommendations were issued for the treatment of private borehole water before
human eonsumption (Ukpong and Okon 2013).
One of the key sourees of BWS eontamination is thought to be from building
underground septie tanks and soak-a-ways (soak pit) too elose to the boreholes. Most of
the West Afriean eountries do not have a eentral wastewater treatment system.
Homeowners are eompelled to build underground soak-a ways in order to dispose of the
domestie waste (Eubara-Manuel and Jumbo 2014). Underground septie tanks and soak-
away loeated at short distanees from borehole water sourees eould damage and leak into
the water system eausing environmental damage (Eubara-Manuel and Jumbo 2014).
Eubara-Manuel and Jumbo (2014) investigated three boreholes and septie tanks that were
23
6m and 9m apart. Water samples from the three borehole water systems were colleeted
and analyzed. The analysis showed a high PH value of 4.4 from two of the three borehole
systems that were 6m and 9m apart. From the sample results, the PH value met the WHO
requirements regardless of the distanee between the boreholes and the septie tanks. The
PH value showed the water being aeidic but within limit. Meanwhile, the third borehole
was determined to have the highest eoliform eontamination indieating that the water was
not good for human eonsumption beeause it was eontaminated by human waste from the
septie tank that was 6m away (Fubara-Manuel and Jumbo 2014).
In Ghana, Akudago et al. (2009) investigated the eause of borehole water systems
drying up in the Voltaian Hydrogeologieal System. The survey result revealed that out of
492 boreholes in the area, about 13% of the boreholes failed after seven years of
operation and 8.5% of the failure was beeause of the breakdown of the hand pumps while
4.5% was beeause of lack of water in the borehole (Akudago et al. 2009). The cause of
borehole drying in the Voltaian region of Ghana was attributed to construction error and
clogged fdters. This was due to possible defective screen and plain pipes (Akudago et al.
2009). Akudago et al. (2009) review examined and assessed the sustainability of BWS
and its concurrent life-cycle relationships.
In another development in Ejigbo, Osun State of Nigeria, Emmanuel and
Bamidele (2013) studied the sustainability of borehole water schemes in the rural area.
The team used a systematic random sampling method to collect data from over 250
questionnaires. The characteristics of their data were from boreholes, their functions, and
agencies that provided the system (Emmanuel and Bamidele 013). Using descriptive and
regression statistical data analysis, different functionalities of boreholes in the area
revealed that over 36 boreholes were in poor serviceable condition out of 64 boreholes
that were evaluated. Consequently, 28 of 64 boreholes were functioning well at the time
data was collected (Emmanuel and Bamidele 2013). According to Emmanuel and
Bamidele (2013), lack of proper maintenance of the BWS was because of the poor socio¬
economic characteristics of respondents and monitoring group by donor agencies.
While lack of maintenance of the BWS affects its sustainability as presented by
Emmanuel and Bamidele (2013), Yong, Mulligan, and Eukue (2015) emphasized that the
24
infiltration and water runoff are the eauses of the presenee of eontaminants in the ground
water. The eontaminants in the ground water would prompt the need for adequate
management of water sourees and remediate them when neeessary (Yong, Mulligan, and
Fukue 2015). “Treatment of water to aehieve levels of quality dietated by drinking water
standards is only one means for water resouree management. The order has to be direeted
toward eliminating or mitigating the sourees of eontamination of water resourees” (Yong,
Mulligan, and Fukue 2015, 77). Nitrates in the soil eould leaeh and enter in the borehole
water system due to heavy rainfall. This may result in the eontamination of the borehole
system, whieh will require treatment. Nitrate for example, is present in the water due to
mineralization of ehemieal eompounds in the soil (Gilli, Mangan, and Mundry 2012).
Oyebande (2001) eoneluded that water problems in Afriea eould result in
eonfliets in Afriea in deeades to eome and eould inerease poverty and environmental
degradation. Researeh in the area of engineering seienees would enable the “Afriean
eeonomies to overeome the devastating potable water problems through effieieney and
sustainability” (Oyebande 2001, 961). However, water system improvement “may be
aehieved through seientifioally designed water harvesting teehnologies from the areas of
water surplus to those of water defieit” (Oyebande 2001, 961). In another study
eondueted by Balogun et al. (2016), the team determined that harvesting of rainwater is
another supplement for water sourees in the rural and urban areas in West Afriea.
Although rainwater is an alternative, it eould be harmful to humans and animals at times
due to aeid rain.
In summary, the literature survey showed that dependeney on only natural
filtration of ground water is not suffieient for human eonsumption. Clearly, water
purifieation system may also be used to purify rainwater in areas of the region where
aeeess to borehole water system is searee. Studies show that most of the borehole water
systems in West Afriea laeked proper maintenanee. The presenee of metals and baeteria
in the borehole water systems indieate a need for filtration prior to use. Although the
ground water is naturally filtered in the aquifer, BWS that are being used are not
equipped with the monitoring system, whieh eould dietate the presenee of metals or
eontaminants in the water. The system does not have filtration system, whieh would be
25
helpful in removing the harmful metals and in disinfeeting the water prior to human
eonsumption. Researeh eonducted proved that the BWS is more eost effective, efficient,
and sustainable than other water sources. A modified borehole water system will be able
to meet capability gaps of monitoring and detection of chemical compound, filtering, and
disinfection of water. Based upon this literature review, a purification system for the
BWS appears to be the most reliable source of a continuous high quality water supply for
the local population as well as U.S. forces operating in West Africa.
26
III. OPERATIONAL ANALYSIS AND USER NEEDS
A. NEEDS ANALYSIS
Safe and good quality water system is eritieally important in West Afriea for U.S.
forees that may operate there in the future. The author grew up in West Afriea and knows
from personal experienee that the borehole water system laeks a purifieation proeess
before eonsumption. Based on his personal knowledge having lived there, there is need
for a system that will purify and disinfect water from the current borehole water system
in West Africa.
• The system needs to be able to provide purified water for 2,000 soldiers or
a village of 2,500 people.
• The system needs to have low operating efficiency such as electric cost
per gallon of water purified.
• The system needs to have high water production rate for allocation of
enough water for 2,000 soldiers or a village of 2,500 people.
• The system needs be low cost, low maintenance, easy to use, and able to
produce safe drinking water.
With the identified need of the current water system in West Africa, Figure 10
shows a simplified needs and opportunities analysis diagram that depicts the sequence of
the operational analysis and user needs process. In this model, the system deficiencies or
capability gaps (monitor, filtration, and disinfection subsystems) are recognized, which
calls for technology improvement. This process would follow user needs determination
resulting in operational objectives for a new or improved system. The operational
analysis process would be the next step, which periodically triggers a functional analysis
based on a set of operational requirements (Coolahan 2012). The water system
modification process would be based on these steps to complete the operational analysis
and user needs.
27
Technology Improvement
Functional
Decomposition
Legacy/Similar System
Information
Figure 10. Simplified Needs and Opportunities Analysis Diagram.
Adapted from Coolahan (2012).
B. OPERATIONAL ANALYSIS
This seetion presents how the system is expeeted to operate and the insights into
what funetionality might be required. This is the foeus of operational analysis. The water
system shall operate in the West Afriean environment where the average temperature is
about 85 degrees. The rainy season occurs between the months of April and October. The
operational analysis of the water system is shown in Figure 11. As illustrated in the
figure, the sequence of operation starts at the power source, which powers the electrical
water pump. For the purpose of this thesis, rainwater and borehole water are used
interchangeably in this water purification system. During the rainy season between April
and October, rainwater from the non-potable storage tank is mostly pumped to the system
for purification. Consequently, during dry season and when rainfall is scarce, the
borehole water is used throughout this period. The interchangeability of rainwater and
borehole water is to make the water purification system more cost effective to maintain.
The water pump pumps rain or borehole water to the three stages of pre-filter assemblies.
The first stage is the pre filter through the system monitor/detector system. The
monitor/detector subsystem detects the presence of contaminants in the water. The water
PH level is determined, recorded, and then displayed on the screen.
The pre-filter removes dust, sediments, smell, odor and large particulates from the
water especially, those that are visible to the human eyes. The second stage, pre-filter,
removes any chlorine and organic compounds that contribute to bad taste in the water. The
28
water then flows through the membrane filter to remove dissolved solids, ion, organic
substances and bacteria in the water. Additionally, this module removes other particulates
that are invisible to the human eyes and flushed at a regular interval to prevent blockage of
the membrane filter. The purified water is stored in the potable water tank. From the water
tank, the potable water flows through the post filter assembly where any impurities
encountered in the water tank are removed prior to disinfection. The molecules that may
cause bad taste of the water are removed at this time. The water then goes through
disinfection system where additives may be added to reintroduce some of the lost minerals in
the water. Once the water is disinfected, the water is now safe for human consumption.
External System
Electric Flow
Water Flow
Figure 11. A Depiction of Operational Concept of the Water System.
C. OPERATIONAL REQUIREMENTS
The capability gaps and technical approach to design the water purification
system have been defined in the objective and problem statement section. It is now
necessary to translate them into a set of operational requirements to identify the
objectives of the water system and how well it wifi perform in its intended environment.
The water system requirement analysis defines functional and performance requirements
based on the water system capability gaps. This process is “performed iteratively with the
29
functional analysis in order to optimize performanee requirements for identified
funetions, and to verify that synthesized solutions ean satisfy eustomer requirements”
(DAU/DSMC 2001,36).
1. High-Level User Requirement
The system needs to be eapable to pump water from the borehole water souree,
filter, purify, store, and disinfeet water prior to delivery to the eonsumers. The high-level
operational requirements of the water system are affordability, easy to use and maintain,
and the eapability for operation without need for a eontinuous external power supply. The
overall design and analysis of the water purifieation system is estimated to be less than
$50,000.
2. System Size
Aeeording to the Marine Combat Water Survival Manual (2002), eaeh soldier
operating in a high temperature environment is expeeted to eonsume at least 2.6 gallons
of drinking water daily. The size of the water purifieation system is determined for a
eombined Battalion of 2,000 soldiers. For eaeh of the 2,000 soldiers to eonsume a daily
requirement of 2.6 gallons of water, about 5,200 gallons of water will be required by the
troops. Using the required 2.6 gallons of water per person in a village of 2,500 people
will amount to 6,500 gallons of water per day. Meanwhile, to prevent water shortage due
to equipment breakdown and to inerease potable water usage due to exeess produetion,
10,000-gallon potable water tank would be needed. Therefore, the eapaeity of the water
tank and the produetion rate per day (10,000 gallons per day) would be more than enough
for a village of 2,500 or a eombined battalion of 2,000 soldiers. For a produetion rate of
10,000 per day, this means that the water purifieation system must produee
approximately 417 gallons of water per hour.
3. Operational Concept
The proposed water system shall be situated in a village in West Afriea where the
U.S. troops are expeeted to operate in the future. The loeation shall be elose to other
Afriean villages that will benefit from the system. It is antieipated that the water system
30
will be shipped from the United States to West Afriea and expected to be operational
within one year. The water system will have components that will deliver and store
purified water. Based on the user needs and system size, the water purification system
will be able to produce 7,000 to 10,000 gallons of water per day.
The system is expected to operate 20 hours per day and the remaining four hours
will be used for minor maintenance such as system fiushing/cleaning, post operation
inspection, daily and turn around inspection, and parts replacement. The system shall be
operated by the U.S. forces’ water technicians throughout the duration they will operate
in West Africa. Thereafter, the local technicians will be trained to operate and maintain
the system.
4. Proposed Maintenance Concept
The proposed maintenance concept of the water system evolved from the
definition of the operational requirements. The system maintenance level shall be
organizational maintenance where the users will perform all the corrective, preventive,
and conditional maintenance. It is not expected that the water system will require major
maintenance. The system maintenance will be simple which includes visual inspection,
operational checkout, external adjustments, removal and replacement of some
components.
United States forces will have on-hand pre-expended parts bins during
deployments, to reduce difficulty to access of spare parts. In the event where there is need
for spare parts, parts may be obtained from local dealers or shipped from the
manufacturers to the military bases in the United States. In addition, the water system
parts will be in the DOD stock system for easy ordering and faster shipment to West
Africa.
5. Environmental Factor
The proposed water system shall be fully operational in an environment with
temperature ranging from 70 to 85 degrees and 84 to 88% humidity. The system shall be
able to withstand wind speed of 40km/h during Harmattan season. Harmattan is a dry
31
wind that blows from northeast in the Western Sahara that oecurs from Deeember to
Mareh. In the event of heavy winds during Harmattan season, the water system shall be
able to withstand any shook and vibration during water flow.
6. System Reliability
The operational availability (Ag) for the overall water system shall be 99.9%,
Mean Time to Failure (MTTF) of less than 10,000 hours, failure rate (k) of 0.0001
failure/hour. Mean Time Between Maintenance (MTBM) shall be greater than one year,
and the maintenance downtime (MDT) shall be less than one hour.
D. FUNCTIONAL ANALYSIS
While the operational analysis illustrates what the water system needs to do in
order to accomplish its operational tasks, functional analysis shows more detailed
analysis of the functionalities required of the system to meet its intended function. The
functional description of the water system “serves as a basis for identification of the
resources necessary for the system to accomplish its tasks” (Blanchard and Fabrycky
2011, 100). Functional analysis is described as “an iterative process of translating system
requirements into detailed criteria and the subsequent identification of the resources
required for system operation and support” (Blanchard and Fabrycky 2011, 100). The
intent of this process is to look at the details of “what” the water system must do and not
“how” the system will do it. In addition, the system requirement will be “broken down to
the subsystem and down to the hierarchal structure as necessary in order to identify input
design criteria and constraints for the various elements of the system” (Blanchard and
Fabrycky 2011, 100). For this thesis and the purpose of the water system, functional
analysis shall involve the functional decomposition of the system. The purpose is to
identify and decompose the vital functions of the water system, which will result in a list
of functions, and sub-functions required of the water system to close the capability gaps.
I. Functional Hierarchy
The functional decomposition enabled the creation of list of functions and sub¬
functions required for the water system. The list of the system functions will now be
32
organized into meaningful information. One useful method of organizing these funetions
and sub-funetions is the funetional hierarehy. Figure 12 presents the functional hierarchy
of the water system. In the Figure, the water system is defined according to its functional
terms and then decomposed from top-level functions into sub-functions. Each of the
functions of the water system is represented by a block diagram and described in terms of
inputs, outputs, and interface requirement. Further, the water system functions “are
arranged in a logical sequence so that any specified operational usage of the system can
be traced in an end-to-end path to indicate the sequential relationship of all functions that
must be accomplished by the system” (NASA/SP 2007, 42).
Figure 12. Functional Hierarchy of the Water System (SV-4).
33
2. Description of the Water System Functions
The functional description allows a deeper understanding of the functionalities of
the water system and describes the system functions that are presented in the functional
hierarchy in Figure 12. The following are the list of all the main systems and sub-systems
that will be supporting the water purification system. In the list, the top two levels of the
functional hierarchy are discussed.
1.0 Pump water to the system: The purpose of the water pump is to pump
water from the borehole water source to increase water pressure that passes through the
water purification system. The pump will be able to turn the itself ON/OFF when the tank
is over pressurized.
1.1 Check power availahility: The water pump will need electrical power to
operate. Prior to starting the pump, the pump will sense for the presence of electrical
power. The water system shall solely operate with electrical power to pump water to the
tanks.
1.2 Check water availahility: The pump will operate when the feed water
flows through it. In order to conserve energy, the pump will verily the presence of water
flowing through the pump to operate.
1.3 Pump non-potahle water: The water pump will pump untreated water to
the non-potable water tank used for laundry, shower, and cleaning.
2.0 Monitor presence of contaminant: Water flows through the
monitor/detector system where the water is cycled for presence of contaminant. The
system will need to monitor and stay abreast of environmental conditions. It will be able
to conduct self-diagnostic test when faulty.
2.1 Detect contaminants in the water: The system will detect the presence
of contaminants in the water during the water-cycling period.
2.2 Record water contamination levels: Once the presence of chemical
compound in the water is detected, the monitor/detector system store the degree of
34
contamination. Based on the level of eontamination, it will indieate green, orange, or red
light. The green light indieator shows that tolerable or no amount of eontaminants is
deteeted and no additional treatment may be neeessary. The orange light eautions the user
of larger level of eontaminants in the water while red indieates that additional water
treatment is required.
2.3 Display results water contamination; The display monitor displays the
level of water eontamination on the sereen for the system operator to see whether
additional treatment of the water is required.
3.0 Remove particulates of matter in the water: The first, seeond, and third
stages of the pre-filter assemblies will perform this funetion. The three filters enable the
removal of suspended solids and partieulates from the water.
3.1 Remove large particulates in the water: The sediment filter, whieh is
the first stage of the pre-filter subsystem, shall be used to remove solid partieles sueh as
sand silt, mud, floating partieulates and dirt.
3.2 Remove organic molecules: The seeond and third stage of the pre-filter
will be used to remove ehlorine in the water. The filter is designed to remove bad taste
and smells that may be present in the water.
4.0 Purify water: The membrane filter is the most effeetive of the filters and
eapable of removing up to 95% of total dissolved solids of 0.0001 mierons in the water.
4.1 Remove visible particulates from the water: The partieulates of matter
that are invisible to the human eye are removed. The impurities removed are baeteria,
viruses, metal eompounds, and inseetieides found in the ground water.
4.2 Remove had taste and odor: To remove taste and odor from the water in
the storage tank. The filter removes moleeule residue from the water produet.
4.3 Protect membrane filter: System over pressurization reduetion of the
membrane is needed to prevent it from being ruptured.
35
4.4 Prevent overfill: Able to shut-off water to prevent excess water from
entering the membrane. When the water level drops in the tank, tank will open to allow
water through the membrane.
4.5 Prevent backward fiow: To prevent the backward flow of treated water
from the potable water storage tank from flowing back to the system.
5.0 Store water: To store purified water and/or rainwater and used to harvest
rainwater. The second potable water tank maintains the supply of purified quality water
in the tank when it is needed by the troops. The potable water tank prevents over
pressurized in the tank when it is full.
5.1 Pump water from storage tank: To pump water from the storage tank to
the consumers. The pump shall automatically start when water is needed and stops when
the pump runs dry.
5.2 Protect water from particulates: The storage tank shall provide airtight
protection of the water against leaks and pollution.
6.0 Disinfect water: Disinfection system inactivates any microorganisms that
passed through purification system.
6.1 Treat water: To kill microorganism in the water.
6.2 Add additives to the water: To dispense water additives when required.
3. Functional Flow Block Diagram
While the functional hierarchy is useful in breaking down high-level functions
and sub-functions required of the water system, it does not adequately display these sub¬
functions in a logically sequential manner. Meanwhile, one tool to use to understand the
system’s functions and architecture is the Functional Flow Block Diagram (FFBD). The
FFBD shows the sequential manner to perform the functions of the water system using a
flow chart (NASA/SP 2007). It presents the sequential relationship of all functions, which
the water system will accomplish. For the water system FFBD shown in Figure 13, a
circle is used to show a summing gate used when AND/OR gate is present in the FFBD.
The AND gate “indicates parallel functions and all conditions that must be satisfied to
36
proceed to the step of the water purifieation proeess” (DAU/DSMC 2001, 50).
Additionally, “an OR is used to indieate that alternative paths ean be satisfied to proeeed.
These symbols are plaeed adjaeent to lines leaving a partieular funetion to indieate
alternative paths and must be earried out in order to eontinue to the next proeess”
(DAU/DSMC 2001,50).
The FFBD for the water system begins from the borehole or rainwater and enters
into a loop proeess, whieh eontinuously loops as it eompletes eaeh water purifieation
eyele. It would then enter an AND gate whieh goes into a parallel funetions of pumping
water, monitoring eontaminant, removing partieulates, and purifying water. Eaeh of these
high-level funetion will enter into its speeifie AND gates for the start of the water
purifieation proeess. The eleetrie power is provided to the pump-to-pump water from the
borehole system. Prior to this event, the pump eheeks simultaneously to ensure of the
availability of power and water. These operational eheeks will be eondueted before
starting of the pump. The pump would first pump water to the non-potable water tank for
laundry, shower, and eleaning. Next, the presenee of eontaminants in the water is
monitored. This funetion will deteet whether eontaminants are present, reeord the
readings, and display data to the system monitor. While monitoring presenee of
eontaminants in the water, the system will eonduet a diagnostie self-test, eheek the level
of eontaminants, and indieate the appropriate light based on the level of eontaminants in
the water.
In the purifieation module, water pressure is provided to the system. The pre-filter
removes partieulates from the water and enters an AND gate whieh goes into a parallel
funetion of removing large partieulates and organie moleeules respeetively. Water enters
into parallel funetion to remove invisible partieulates as well as bad taste and odor. The
system now goes through a sequenee of shutting off water when the tank is full to proteet
the membrane from being ruptured and to prevent baekward flow of treated water to the
system. The pump now pumps water and stored it in the storage tank, whieh will provide
airtight proteetion and monitor water pressure. The water pump in the storage tank is
water-eooled. The purified water enters into disinfeetion proeess where the disinfeetion
system provides UV energy. It will eonduet UV treatment of the water and add additives
37
as appropriate to replenish the minerals that may have been lost in the water during the
purification process. System will continue to loop and the water purification process
continues until the storage tank is full. The loop sequence will stop once the cycles are
completed. Potable water will now be available for the consumers.
38
Figure 13. Water System FFBD.
39
4. Timeline Analysis
As shown in Figure 13, the water system FFBD shows the logical sequence of
what must happen during the water purification and treatment process; but it does not
show a time duration to functions and between the functions of the system. In order to
understand the time-critical requirements and the detail defining durations of various
functions, a time line analysis (TLA) is used. For the water purification system, TLA is
helpful in “defining concurrency, overlapping, and sequential relationships of functions
and task” (DAU/DSMC 2001, 54). Furthermore, TLA defines the “time critical functions
that directly affect water system availability, operating time, and maintenance downtime”
(DAU/DSMC 2001,54).
Figure 14 shows the TLA result of the water system FFBD. CORE software has
the capability of simulating a FFBD without need for an input data. The time that is
required to perform the water system functions and its sub-functions are demonstrated on
a bar chart depicting how the timelines relate to each other. The TLA is used
simultaneously with FFBD to capture the duration and sequence of the function of the
water system (NASA/SP 2007). For the simulation in Figure 14, it took approximately
650 units of time to complete the water purification process of six cycles.
The time line analysis process of the first cycle began from 0 second and
completed at time 110 minutes. The second process started again at 110 minutes and
completed the cycle at 215 minutes. At 225 minutes, the third cycle commenced and went
through the purification process again and completed at time 330 minutes. Furthermore,
the fourth cycle started at 340 minutes and ended at 425 minutes. Similarly, the fifth
cycle started at 450 minutes and ended at 530 minutes. Finally, the sixth cycle
commenced water purification at time 560 minutes and ended at 650 minutes once the
exit criteria were met. From the need analysis, the water purification system will produce
approximately 417 gallons of water per hour for a production rate of 10,000 gallons per
day. Given the 650 minutes for the system to go through six water production cycles, the
system produced approximately 4,514 gallons of water within 10 hours 23 minutes. This
means that if the system operates for 20 hours in a day as required, it will have produced
40
about 9,028 gallons of water, meeting close to the user need of 10,000 gallons of potable
water availability per day.
0.0 CaMRPOrABtC WATER
O.ICOUEa RAINWATB)
I.KHECX POWER AVAIlABaiTY
iKHEaWATRAVAllABIUTY
1.3 FUMP TO M>fPOTABlE TANK
MDeTKTCONTAMIfiWT
2.2 RECORD READtNSS
2.3 DISnAY DATA
3.1 REHOVflAROEMRTIClIUTES
3.2 REMOVt ORGANIC MOUOUS
4.! REMOVE INViSlBU PART1CUUTES
4.2 REHDVteAOOOORO TASTE
4.3 PROTEa MEMBRANE
4.4 SHUT Off WATER
4.5 PREVENT BACKWARD now
3.0 STORE WATER
5.1 FOMP WATER TO STORAGE TANK
S.2FflOTEa WATER
4.0 DISINFECT WATER
6.1 W TREATMENT
6.2 ADO ADDITIVES
aOE I CONFUTE
CYQE 2 COMPUTE
aOE 3 CONFUTE
■
Figure 14. Time Line Analysis for the Water Purification Operation
E. LIST OF SYSTEM REQUIREMENTS
The system requirements listed in Table 3 are based upon the functional
decomposition of the water system. These components would be used to modify the BWS
in order to meet the capability gaps in the area of detection and monitoring of chemical
compounds, filtering, and disinfection. From an innovative perspective of the water
system, the non-functional requirements will enable the identification and description of
the constraints such as system reliability, maintainability, interoperability, and usability.
It further demonstrates traceability from the physical components back to the specific
requirement and user needs.
41
Furthermore, each technical specification is justified in the rationale column to
enhance clarity. The specifications have their associated functions, which can be traced
back to the established functional decomposition.
42
Table 3. List of Water System Requirements
Requirement
Associated
Functions
Rational
The system booster pump pressure shall
be 80 psi at standard temperature of 77
degrees.
1.0
Booster pump is needed to pump water from the
borehole to the non-potable water tank. 80 psi is the
output pressure of the pump lAW with the system
specification found on
https://www.espwaterproducts.com
The system pump shall operate with
eleetrieal power.
1.0
In West Africa, power is not consistent. It may take
days to have electrical power. There is need for an
electrical power to pump water from the borehole.
The system shall be able to draw 60 kw/h
eleetrieal power.
1.1
Because electricity is not always available in West
Africa, the system will need power to operate the
water pump. Solar panel information was retrieved
from http://www.mrsolar.com/online-solar-l-
85kw-remote-power-system/
The system water flow rate shall be
between 7,000 to 10,000 GPD.
1.0, 3.0,
4.0, 5.0
From the size analysis, it is expected that the troops
need at least 5,200 gallons of water per day.
Therefore, any system that will produce more than
5,200 GPD would be beneficial.
The system monitor/deteetor system shall
be able to conduct self-test and system
updates.
2.3
Most of the monitor/detector systems in the market
are incorporated with software that can be
automatically synced to updates and capable of
conducting self-test. It is anticipated that the
monitor/detector system will such capability.
The monitor/detector display panel shall
maintain 0.98 reliability.
2.3
The monitor/detector system will maintain 0.98
reliability due to established MTBF by the
manufacturer.
43
Requirement
Associated
Functions
Rational
The system shall incorporate a built-in
test capability that will allow for fault
isolation to the unit level with a 98% self¬
test thoroughness.
2.2, 2.3
Most of the monitor/detector systems in the market
are incorporated with built-in test that that will
enhance fault isolation. It is anticipated that the
monitor/detector system will such capability.
The system shall be capable of removing
99.99% of dissolved solid of 0.0001
microns, or greater.
4.1
Most water filters are designed to inactive up to
99.99% of the dissolved solid. It is the author’s
opinion that the water filters should be able to
perform similar functions.
The system pressure switch shall turn
ON/OFF pump when tank is over
pressured.
5.1
Purified water should not be wasted in West Africa
as it is scarce to have access to it. The storage tank
will have the safety switch to prevent over flow.
The system shall use sunlight at
frequency of 254 nanometers to kill
microorganism.
6.1
Most disinfectants in the market are designed to use
up to the frequency of 254 nanometers to kill
microorganisms.
Each of the system components shall
have a Mean Time Between Failure
(MTBF) of at least 10,000 hours (pre and
post filters) and 20,000 hours (for
membrane filters.
N/A
MTBF is derived from the annual requirement of
replacement of the sediment, carbon, and ultrafilter
elements (8,640 hours per year). Similarly,
membrane filters are to be replaced biennially
(17,280 hours).
The system shall be easy to maintain and
have a Mean Time to Repair (MTR),
Mean Time Between Maintenance
(MTBM), and Maintenance Down Time
(MDT) of 1 hour.
N/A
Removal and replacement of filters and housing is
simple. It is the author’s opinion as a former
aircraft mechanic that it should not take more than
1 hour to conduct the maintenance.
The system operational availability shall
be 99.99% with 95% confidence interval.
N/A
It is anticipated that the system will be available
99.99% of the time. This is because spare parts will
be available in the military supply system for easy
access. Additionally, troops will stock up spare
parts prior to deployment to West Africa.
The system operation cycle shall be 20
N/A
From the result of the simulation of the TLA in
44
Requirement
Associated
Functions
Rational
hours ON and 4 hours OFF.
Figure 17, it took ten hours to produoe 4,513.93
gallons of water. In 20 hours, the system will have
produced 9,027.86 gallons of water, which is more
water than the 5,200 daily requirement. The
remaining 4 hours during system shut down would
be used for minor maintenance.
The system shall be able to withstand
wind speed of 40 km/h during Harmattan
season.
N/A
The system will be enclosed in a shed constructed
with bricks. The 40 km/h Harmattan wind will not
affect the system.
The system shall interoperate with the
pump and eleetrieal generation system.
N/A
The pump, power, monitor and disinfection
systems are external systems and the system will
interoperate with them.
The system shall be able to withstand any
shook and vibration during water flow.
N/A
With the water system being enclosed in a shed,
any shock and vibration will not affect the system.
The system shall have a dimension of not
more than 61”x 33”x 54.”
N/A
The dimension is based on the comparisons of
several distillations plants and size of reverse
osmosis plants.
The system weight shall be not more than
80001bs.
N/A
The dimension is based on the comparisons of
several distillations plants and size of reverse
osmosis plants.
45
F. TECHNOLOGY FEASIBILITY
Operational and technical feasibility study of the water system is to identify and
determine the possible design approaches or an alternative that could be selected in order
to meet the user need for a new system (Blanchard and Fabrycky 2011). From an
innovative perspective of the water purification system, this study evaluated different
feasible approaches to determine the most desirable water purification system that met
the capability gaps in the area of detecting and monitoring of chemical compound,
filtering, and disinfection of water. Furthermore, the most desirable functional areas of
the water system that were investigated are system cost, production rate, usability, and
safety criteria. The BWS is inefficient for U.S. troops should they operate in West Africa
in the future due to the current capability. Therefore, a cost effective system that will
provide safe drinking water to U.S. forces operating in West Africa is required.
During this design and analysis study, several commercial off-the-shelf (COTS)
water purification systems and components were investigated to determine the preferred
system that would be used to fill the capability gaps. The Pugh Matrix method was used
to determine the appropriate water purification system for the BWS in West Africa. Pugh
Matrix allows a “comparison of several design concepts selection using a scoring matrix”
(Stevens 2015, 4). The three systems that were considered are Modified Reverse Osmosis
System (MROS), Water Distillation System (WDS), and the status quo (Contracted
Water Supplier (CWS)). The benefits under consideration include operating efficiency,
system cost, production rate, and usability and safety. The most important benefit of the
water system alternatives is the system cost while usability is the least important attribute.
• Operating Efficiency is the rate at which the water system consumes
resources such as electric cost per gallons.
• Cost is the cost of the system and components.
• Production Rate is the gallons of water production per day.
• Usability and Safety: Usability is the ease of use of the system to achieve
quantified objectives and satisfaction of the customer in a quantified
context. Safety is the security of the system during operation or
transportation of water from one base to the other.
46
1. Modified Reverse Osmosis System (MROS)
The MROS is a multi-staged water purifieation system designed to treat over
10,000 gallons of water per day. It is designed to be able to maintain tolerable
performance, high recovery rates, low power consumption, easy to use, inexpensive
maintenance and operation cost. The water purification system is configured with four
pre-filters, six membranes, and four post-filter subsystems. The system overall
acquisition cost is expected to be $13,800. The manufacturer offers a one-year limited
factory warranty. Its shipping weight is 5001bs. Figure 15 illustrates a depiction of likely
size and dimension of MROS.
Source: U.S. Water Systems (https://www.uswatersystems.com/us-water-craftromaster).
Figure 15. A Depiction of size and dimension of MROS.
2. Water Distillation System (WDS)
VC6000 is a state-of-the-art vapor compression water distillation system that has the
capability of producing up to 6000 gallons of water per day as well as distilled water. The
system overall acquisition cost is estimated to be $155,731. The manufacturer offers a one-year
limited factory warranty. Its shipping weight is SOOOlbs and uses 0.085 kw/hour of electricity
per gallon. Figure 16 illustrates a VC 6000 vapor compression water distillation system.
47
Source: Norland International (www.h2olabs.com) (2016).
Figure 16. Depiction of Vapor Compression Water Distillation System
(VC 6000).
3. Contracted Water Supplier (CWS)
The Department of Defense (DOD) contracted private companies to supply
potable water to the U.S. troops in Iraq and Afghanistan. In Afghanistan, it cost $4.69 per
gallon to deliver bottled water to soldiers at a daily demand of 5.3 gallons per Marine
(Lash 2011). If a total of 20,000 troops were to be served, for example, the cost to deliver
bottled water would be $497,140 per day in Afghanistan (Lash 2011).
Table 4 shows the Pugh Matrix attributes evaluation for three candidate
alternatives. The alternatives were evaluated against five criteria. In creating a Pugh
Matrix, the Contracted Water Supplier is selected as the “baseline” because it is the
method being used to provide potable water to the troops. Each criterion of the baseline
has a corresponding quantifiable attribute. The operating efficiency of the status quo is
$756,028 per month. Comparing this amount to the other alternatives ($100 per month
and $3,300 per month), it can be seen that it was very expensive to deliver potable water
48
in Iraq and Afghanistan. For the system eost eriterion, a gallon of water cost $1 in
Walmart and 2.6 gallons of water is expected to be consumed by a soldier operating in
hot environment. Therefore, it will cost $161,200 per month for a unit of 2,000 soldiers to
consume 2.6 gallons of water daily. Meanwhile, the cost to acquire MROS and WDS,
which are capable of producing potable water are $13,800 and $155,731, respectively.
The production rate of the baseline is over 10,000 GPD while that of MROS and
WDS are 10,000 GPD and 6,000 GPD. Both the usability and safety of the alternatives
are measured in percent. It is expected that the usability of the baseline is 100% because
the soldiers preferred bottled water due to its portability and ease of use. The usability of
MROS is estimated to be 90% because the system is expected to perform water
purification operation for 20 hours per day while the remaining four hours are used for
maintenance. The usability of WDS is expected to be 100% because it is designed to
produce about 6,000 GPD. If time is allocated for maintenance without enough water in
the storage, there may be shortage of water, which would take several hours to make up.
The safety of bottled water is 90% because it could support bacteria growth in the
water if not stored in a well-ventilated room (Lash 2011). The safety risk level of both
MROS and WDS are 98% considering possibility of contaminants in the system if
maintenance is not performed properly. From the analysis in Table 4, it can be seen that
MROS has the highest attribute.
Table 4. Alternative Data
PUGH EVALUATl
ION MATRIX
ALTERNATIVES
CRITERIA
UNITS
BASELINE
(IRAQ)
MROS
WDS
Operating
Efficiency
$/GAL
$756,028
(per month)
$100
(per month)
$3,300
(per month)
System Cost
$ 1/GAL
$161,200
(per month)
$13,800
(cost of system)
$155,731 (cost
of system)
Production Rate
GPD
>10,000 GPD
10,000 GPD
6,000 GPD
Usability
%
100%
90%
100%
Safety
Risk level in
%
90%
98%
98%
49
In Table 5, each criterion is rated against the corresponding baseline as follows:
“+” Alternative is Better than the Baseline concept
“S” Alternative is Same as the Baseline concept
Alternative is Worse than the Baseline concept
The Baseline was compared with the alternatives because it is currently being
used. The Baseline column is marked “DATUM” since it is not required to be scored. For
each candidate alternative, the total score was calculated by summing the number of +s,
Same, and -s. The MROS appeared to have the highest score of 4 and would be the
preferred water purification for the BWS.
Table 5. System Selection Using Pugh Matrix.
Pugh Matrix
Concept Selection Legend
Better +
Same S
Worse
BASELINE
(IRAQ)
MROS
WDS
Key Criteria
Operating Efficiency
D
+
+
Cost
A
+
-
Production Rate
T
S
-
Usability
U
+
S
Safety
M
+
+
Sum of Positives
4
2
Sum of Negatives
0
2
Sum of Sames
1
1
TOTALS
4
0
Adapted from Alex Sugimoto (https://alex-sugimoto.squarespaee.eom/s/Pugh-Matrix-
Template.xls) (2016).
50
G. COST ANALYSIS OF THE WATER PURIFICATION SYSTEM
The feasibility analysis was benefieial in determining the most desirable
purification system. Cost analysis of the water system will further aid in determining and
comparing the benefits and costs of each of the alternatives to meet the system objective.
Cost Analysis is the prediction of the anticipated expenditures associated with each of the
water system alternatives (Boensel 2016). The water system planning horizon is 15 years.
All the feasible ways to satisfy the objective has been considered; however, three
alternatives to be considered are the Modified Reverse Osmosis System (MROS), Water
Distillation System (WDS), and Contracted Water Supplier (CWS). For the cost analysis
of the water system, the time horizon is 15 years and the real discount rate of 1.0% is
applied to the costs. The discount rate is published yearly in Office of Management and
Budget (0MB) Circular A-94, Appendix C.
a. Alternative A: MROS
The cost-breakdown shown in Table 6 is a “linear” list whereby the total cost of
the MROS was calculated by adding together the costs of all items. The rationale of the
cost for each item is shown in Table 6. Table 7 presents the cost analysis summary of the
MROS. The MROS has a one-year factory warranty for the components and modules.
The total investment cost during the first year is estimated to be $43,837, as shown in
Table 7. The cost of the components and subsystems used to assemble the prototype is
$300. The prototype is categorized as part of research and development (R&D) cost.
Since the system is under manufacturer’s warranty for one year and no maintenance is
due, the fuel and electricity costs were estimated to be $3,600 for a total cost of $47,737
during the first year.
51
Table 6. Cost Breakdown of MROS
Task Number
Items
Cost
Rationale
1.0
Modified Reverse Osmosis System (Investment)
(Non-Recurring)
1.1
Borehole Construction
$ 3,000
The author constructed a borehole in Nigeria recently. Estimate
is based on experience.
1.2
System and components
$ 13,800
Quote from (www.uswatersystems.com).
1.2.1
Chemical counpound monitor
$ 260
Quote fi'om (www.uswatersystems.com).
1.2.2
Disinfectant
$ 100
Quote fi’om (www.uswatersystems.com).
1.2.3
7.5 KW Solar Grid Power Kit
$ 9,932
Estimate fi'om (www.mrsolar.eom/online-solar-7500-watt-grid-
tie- solar-power- system-kit/).
1.2.3.1
Initial Labor
$ 300
Labor estimate based on author's experience in Nigeria.
1.2.4
Generator Cost
$ 500
Estimated cost of medium sized generator at Home Depot
(www.homedepot.com).
1.2.5
Punp
$ 245
Obtained from (www.uswatersystems.com).
1.2.6
Storage Tanks
1.2.6.1
Rain Water Tank
$ 1,000
Tank cost estimate in Nigeria based on author's experience.
1.2.6.2
Potable Water Tank
$ 1,000
Tank cost estimate in Nigeria based on author's experience.
1.2.6.3
Non-potable Water Tank
$ 1,000
Tank cost estimate in Nigeria based on author's experience.
1.3
Slipping (20 ft container)
$ 3,850
Quote from Shp overseas (www.shpoverseas.com).
1.3.1
Clearing
$ 2,000
Quote from clearing agent.
1.3.2
Transportation to destination
$ 500
Estimated transportation cost in Nigeria.
1.4
Training (Per day for 1 day)
$ 650
Estimated training cost per day.
1.5
Initial Labor
$ 200
Estimated initial labor cost based on the author's experience.
1.6
Prototype model
$ 300
Quote from (www.uswatersysterrB.com) and
(www.espwateproducts.com)
1.7
System protective enclosure
1.7.1
Building Materials for system enclosure construction
$ 5,000
Estimated cost for building materials based on author's
experience in Nigeria.
1.7.2
Labor for enclosure construction
$ 500
Labor estimate based on author's experience in Nigeria.
Operation and service
(Recuning)
1.8
Parts (per year)
$ 3,665
Quote from (www.espwateproducts.com).
1.9
Electric Service (per year)
$ 1,200
Estimated based on the manufecturers advertisement ($100 per
month)
2.0
Fuel (per year)
$ 2,400
Estimated cost of fuel based on author's experience in
Nigeria{$200 per month).
2.1
Repair cost (per year)
$ 2,400
Estimated cost to repair system per year ($200 per month).
(Non-Recurring)
2.2
Overhaul (at year 7 of investment)
$ 5,000
Expected cost of system overhaul based on cost of each
conponent.
Total
$ 58,802
The system is expeeted to be overhauled during the seventh year at the estimated eost
of $5,000. Beginning the following year, after the faetory warranty would have ran out, the eost
of the eomponents that are to be replaeed annually in aeeordanee with manufaeturer’s
reeommendations will inerease the operation and support (O&S) eost to $6,517. Similarly,
replaeement of the eomponents that are reeommended to be replaeed biennially will be
eondueted and the total O&S eost would now be $9,677. This operation and support proeess is
expeeted to eontinue for the entire life eyele of the system. Additionally, the sum of R&D,
Investment, O&S, and Salvage value has aNPV of $157,589.00.
52
Table 7. Cost Analysis Summary of the MROS
1 1 Cost Summary
1 Alternative: Modified Reverse Osmosis System
Economic Life : 15
1 1 1 1 1 1 1
Pn)granVPn)ject Costs
Real Rate
Year
R&D
Investment
O&S
Salvage
Annual Cost
Discount Factor
Present Value
0.01
Project Year
FY
0
2016
A
300 1
$
43,837 1
$
3,600
$
$
47,737
1
$47,737
1
2017
$
$
$
6,517
$
$
6,517
0.99009901
$6,452
2
2018
$
$
$
9,677
$
$
9,677
0.980296049
$9,486
3
2019
$
$
$
6,517
$
$
6,517
0.970590148
$6,325
4
2020
$
$
$
9,677
$
$
9,677
0.960980344
$9,299
5
2021
$
$
$
6,517
$
$
6,517
0.951465688
$6,201
6
2022
$
$
$
9,677
$
$
9,677
0.942045235
$9,116
7
2023
$
1 5
5,000 1
$
6,517
$
$
11,517
0.932718055
$10,742
8
2024
$
$
$
9,677
$
$
9,677
0.923483222
$8,937
9
2025
$
$
$
6,517
$
$
6,517
0.914339824
$5,959
10
2026
$
$
$
9,677
$
$
9,677
0.905286955
$8,760
11
2027
$
$
$
6,517
$
$
6,517
0.896323718
$5,841
12
2028
$
$
$
9,677
$
$
9,677
0.887449225
$8,588
13
2029
$
$
$
6,517
$
$
6,517
0.878662599
$5,726
14
2030
$
$
$
9,677
$
$
9,677
0.86996297
$8,419
Total
300 1
$
48,837 1
$
116,958
$
$
166,095
$157,589
b. Alternative B: WDS
The eost breakdown for eaeh item during the aequisitioning period of the WDS is
shown in Table 8. Eaeh eost of the WDS item is justified as illustrated in Table 8. The
WDS has one-year warranty for all eomponents and its expeeted life eyele is 15 years.
The investment eost of the system during the first year will be $188,018 as shown in
Table 9. Due to the manufaeturer’s warranty, any repairs performed during this period
would be paid by the manufaeturers. Therefore, eleetrieity and fuel eosts will be $17,700
during the first year of O&S of the system. The annual eost for the first year was
estimated to be $205,718. Beginning the following year, the eost of spare parts, generator
repair, and system repair were added to the fuel and eleetrie usage eosts for a total O&S
eost of $57,900. The system is expeeted to be overhauled during the seventh year at the
eost of $50,000. This overhaul maintenanee will inerease the annual eost to $107,900.
WDS NPV was ealeulated to be $1,005,268.
53
Tables. Cost-Breakdown of WDS
Task Number
Items
Cost
Rationale
1.0
Water Distillation System (Investment)
(Non-Recurring)
1.1
Borehole construction
$ 3,000
The author constructed a borehole in Nigeria. Estimate is
based on experience.
1.2
VC6000 Commercial Distiller
$ 155,731
Quote from (www.uswatersystems.com).
1.2.1
Chemical compound monitor
$ 260
Quote from (www.uswatersystems.com).
1.2.2
Disinfectant
$ 100
Quote from (www.uswatersystems.com).
1.2.3
Water pump
$ 245
Obtained from (www.uswatersystems.com).
1.2.4
Potable water tank
$ 1,000
Tank cost estimate based on author's experience in Nigeria.
1.2.5
7.4 KW Solar Grid Power Kit
$ 9,932
Estimate from (www.mrsolar.com/online-solar-7500-watt-
grid-tie- solar-power- system-kit)
1.2.5.1
Labor
$ 300
Labor estimate based on author's experience in Nigeria.
1.2.6
Generator cost
$ 500
Estimated cost of medium sized generator at Home Depot
(www.homedepot.com).
1.2.7
Initial labor
$ 200
Estimated initial labor cost based on the author's experience
in Nigeria.
1.3
Shipping (per 40 ft container)
$ 5,000
Quote from Ship Overseas (www.shipoverseas.com).
1.3.1
Clearing
Quote from clearing agent.
1.3.2
Transportation to destination
$ 500
Estimated transportation cost in Nigeria.
1.4
Training (per day tor 5 days)
$ 3,750
Quote tor initial training per day ($695/pay) from
(www.h2 olab s. com).
1.5
Building Materials for system enclosure
$ 5,000
Estimated cost for building materials based on author's
experience in Nigeria.
1.5.1
Labor for enclosure construction
$ 500
Labor estimate based on author's experience in Nigeria.
Operation and Service
(Recurring)
1.6
Electric service per day (per month)
$ 15,300
Based on Quote specification (0.085/US Gallon x 6000
gallons/day x 30 days).
1.7
Fuel cost (per year)
$ 2,400
Estimated cost of fuel based on author's experience
($200/month).
1.8
Generator repair cost (per year)
$ 200
Estimated cost to repair generator per year.
1.9
Parts cost (per year)
$ 30,000
Annual cost to replace components. Quote from
(www. h2olab s. com).
2.0
Repair cost (per year)
$ 10,000
Estimated repair cost of VC6000/year
(Non-Recurring)
2.1
Overhaul (at year 7 of investment)
$ 50,000
Expected cost of system overhaul
Total
$ 295,918
54
Table 9. Cost Analysis Summary of the WDS
1 II 1 ICost Summary | | | | |
1
Alternative: Water Distillation System
Economic Life: 15
1
ProgramT*roject Costs
Real Rate
Year
R&D
Investment
O&S
Salvage
Annual Cost
Discount Factor
Present Value
0.01
Project Year
FY
0
2016
$
A
188,018 1
$
17,700
$
$
205,718
1
$205,718
1
2017
j
$
$
57,900
$
$
57,900
0.99009901
$57,327
2
2018
$
$
$
57,900
$
$
57,900
0.980296049
$56,759
3
2019
$
$
$
57,900
$
$
57,900
0.970590148
$56,197
4
2020
j
$
$
57,900
$
$
57,900
0.960980344
$55,641
5
2021
$
$
$
57,900
$
$
57,900
0.951465688
$55,090
6
2022
$
$
$
57,900
$
$
57,900
0.942045235
$54,544
7
2023
$
A
50,000 1
$
57,900
$
$
107,900
0.932718055
$100,640
8
2024
$
$
$
57,900
$
$
57,900
0.923483222
$53,470
9
2025
$
$
$
57,900
$
$
57,900
0.914339824
$52,940
10
2026
$
$
$
57,900
$
$
57,900
0.905286955
$52,416
11
$
$
$
57,900
$
$
57,900
0.896323718
$51,897
12
2028
$
$
$
57,900
$
$
57,900
0.887449225
$51,383
13
2029
$
$
$
57,900
$
$
57,900
0.878662599
$50,875
14
2030
$
$
$
57,900
$
$
57,900
0.86996297
$50,371
Total
$
A
238,018 1
$
828,300
$
$
1,066,318
$1,005,268
c. Alternative C: CWS
The bottom-up eost-breakdown for CWS based on estimates is shown for each
item in Table 10. Each cost is justified in Table 10 to show how the data was obtained.
The DOD contracted private companies to supply water to the U.S. troops while in Iraq
and Afghanistan. Using data from that experience, the cost breakdown in Table 10 shows
that, the cost of a gallon of water is $1. It costs $4.69 to deliver water to the troops. Each
soldier was expected to consume about 2.6 gallons of water daily while operating in hot
environment. Therefore, the total cost of water consumption for 2,000 soldiers in a day
would be $5,200. However, in a month, the total cost to buy bottled water for the troops
would be $156,000. In a year, it would cost the sum of $1,872,000. Additionally, it costs
a total of $8,779,680 to deliver water to the troops in Iraq and Afghanistan annually.
The cost analysis of CWS in Table 11 shows that the first year of the initial water
supply contract was $10,657,180. This amount is in addition for the construction of an
enclosure that would house the bottled water. O&S cost is not expected during the first
year because the initial cost of water and the delivery cost have already been added as
part of the investment cost. Subsequent years of the contract would cost the sum of
55
$10,651,680 annually to supply water to the troops for 15 years. With the given
ealculations, the NPV of CWS alternative will be $149,168,463.
The NPV derived from the eost analysis of eaeh design alternative. The NPV of
MROS was ealeulated to be $157,589 while that of WDS and CWS are $1,005,268.00
and $149,168,463 respectively. The NPV shows that it would be more cost-effective to
acquire the MROS based on the total cost.
Table 10. Cost-Breakdown of the CWS
Task Number
Items
Cost
Rational
1.0
Contracted Water Supplier (Initial Contract)
(Recurring)
1.1
Bottled water/ gallon/troop/ year)
$ 1,872,000
$l/gallon (www.walmart.com) x 2.6 gallons x 2,000 troops x 30
da>^ ^ $156,000 per month.
1.2
Water delivery/gallon/day/year
$ 8,779,680
$4.69/gallon/day (National Defense 2011) x 2.6 gallons x 2,000
troops x 30 days ^ $731,640.00 per month.
1.2.1
Shaping (per 40 ft container)
$
1.2.2
Clearing cost per container
$
1.2.3
Labor
$
1.3
Shelter
(Non-Recurring)
1.3.1
Building Materials for water storage unit
$ 5,000
Estimated building materials cost based on author's experience in
Nigeria.
1.3.2
Labor for storage unit construction
O
o
Estimated labor cost based on author's experience in Nigeria.
Totai
$ 10,657,180
Table 11. Cost Analysis Summary of the CWS
Ill 1 ICost Summary | | | | | |
1
Alternative: Contracted Water Supplier
Econonuc Life: 15
1
1 1 1 1 III II II
Program/Pnijcct Costs
Real Rate
Year
R&D
Investment
O&S
Salvage
Annual Cost
Discount Factor
Present Value
0.01
Project Year
FY
0
2016
$
A
10,657,180 1
$
$
$
10,657,180
1
$10,657,180
1
2017
$
$
$
10,651,680
$
$
10,651,680
0.99009901
$10,546,218
2
2018
$
$
$
10,651,680
$
$
10,651,680
0.980296049
$10,441,800
3
2019
$
$
$
10,651,680
$
$
10,651,680
0.970590148
$10,338,416
4
2020
$
$
$
10,651,680
$
$
10,651,680
0.960980344
$10,236,055
5
2021
$
$
$
10,651,680
$
$
10,651,680
0.951465688
$10,134,708
6
2022
$
$
$
10,651,680
$
$
10,651,680
0.942045235
$10,034,364
7
2023
$
$
$
10,651,680
$
$
10,651,680
0.932718055
$9,935,014
8
2024
$
$
$
10,651,680
$
$
10,651,680
0.923483222
$9,836,648
9
2025
$
$
$
10,651,680
$
$
10,651,680
0.914339824
$9,739,255
10
2026
$
$
$
10,651,680
$
$
10,651,680
0.905286955
$9,642,827
11
2027
$
$
$
10,651,680
$
$
10,651,680
0.896323718
$9,547,353
12
2028
$
$
$
10,651,680
$
$
10,651,680
0.887449225
$9,452,825
13
2029
$
$
$
10,651,680
$
$
10,651,680
0.878662599
$9,359,233
14
2030
$
$
$
10,651,680
$
$
10,651,680
0.86996297
$9,266,567
Total
$
10,657,180 1
$
149,123,520
$
$
159,780,700
$149,168,464
56
IV. DETAIL DESIGN OF SYSTEM COMPONENTS
A. SYSTEM DESCRIPTION
The water purification system comprises of three reverse osmosis subsystems and
seven external components. The three subsystems are pre-filter, membrane filter, and
post-filter. These subsystems make up the water purification system. The seven external
components are pump, power source, monitor/detector, disinfectant, storage tank, non-
potable water tank, and borehole. These components will enhance the water purification
and treatment process. Figure 17 shows the composition and interactions of the water
purification system. This system interface diagram is annotated with operational activities
of each of the subsystem and external components showing how they interact with one
another to enhance the water purification process.
Figure 17. System Interface Diagram (SV-1)
Figure 18 shows the top-level system architecture of the MROS. It describes how
various requirements of the system interaction, the system configuration and operational
interfaces. The system architecture is derived from the description of the system
operational requirements, functional requirements, system technical specification, and the
57
maintenance and support concept. Each of the top-level of the external components and
subsystems are further decomposed to the second level.
Figure 18. Physical Decomposition Level One for the Water Purification
System
1. Power System
Figure 19 shows the second level of the physical decomposition of the power
system. For the purpose of this thesis, there are three power source options: city
electricity, solar energy and emergency generator. In West Africa, electric distribution is
not consistent. Similarly, there may be scarcity of fuel for the emergency generator.
Therefore, there is need for both solar power and emergency generator for a continuous
pumping of water from the borehole to the purification system. For a cost effective
design, the use of solar power will be optional while an emergency generator is used. The
physical decomposition of the solar panel is incorporated to the decomposition of the
power subsystem as shown in Figure 19.
Furthermore, the next level illustrates the physical decomposition of the solar
panel. For the purpose of the improved water system, the system shall be incorporated
and operate by solar panel or electric generator for a continuous pumping of water during
the purification process. Due to the constant power loss in most of the West African
countries, solar energy and emergency generator shall be the power source for the electric
pump.
58
Figure 19. Physical Decomposition Level Two for the Power System
2. Monitor/Detector System
Figure 20 shows the physical decomposition level two for the monitor/detector
system. This subsystem is vital in monitoring and detecting the level of chemical
compound in the water prior to start of the purification process. The monitor/detector
system consists of display screen, potential hydrogen (PH) detector, recorder, and sensor.
Non-potable water will flow through this system prior to the start of water purification.
The display screen will display the content of any chemical compound in the water with
the aid of the PH detector and then record the values in the system computer memory. It
monitors both the feed Total Dissolved Solids (TDS) and product TDS levels to display
salt rejection percentage and membrane performance. The monitor/detector system
displays the product water TDS and conductivity levels, which are useful in evaluating
the performance of the water system (AXEON 2013). Sensor attached to the monitor is
used to obtain the exact chemical compound that are being detected. This will enhance
the detection the quantity of fluoride, chlorine, lead, pesticides, nitrates, and sulfates in
the water.
59
Figure 20. Physical Decomposition Level Two for the Monitor/Detector
System
3. Pump Systems
The MROS does not require electricity to operate, it only needs water pressure to
run. The pump system is chosen to pump water from the borehole water source to the
water purification system. It consists of both electrical and mechanical pumps as shown
in the physical decomposition of the subsystem in Figure 21. Currently, most of the
borehole systems use the mechanical pump. The mechanical pump is too slow and takes
hours to fill up the potable water tank. An electrical pump is incorporated to the design to
speed up the water purification process. When the electrical pump is inoperable, the
mechanical pump option will be used to pump water to the water purification system in
order to start the purification process. The water purification system will use a pump and
motor combination. The motor is available in standard voltage of 220V, 60 Hertz, 3
Phase, and 27 Ampere. The pump type used is a vertical multi-stage centrifugal steel
pump. Further, the pump is not to be run dry without sufficient feed water to prevent it
from being damaged. The pump is fed with filtered water to avoid it from being
susceptible to sediment and debris.
60
Figure 21. Physical Decomposition Level Two for the Pump System
4. Pre-Filter Subsystem
Next is the physical decomposition of the pre-filter subsystem as shown in Figure
22. To improve reliability and dependability of the water system, the pre-filter has two
sets of four stages: Sediment filter 1, Carbon filter 1 and Sediment filter 1, Carbon filter
2. The reliability module of the water system is described in detail in Chapter IV, Section
C of this report. The pre-filters are supplied with 5-micron sediment pre-filters and two
10-micron carbon block pre-filters. During the purification process, water will flow
through these three stages of the pre-filter subsystem before being sent to the membrane
subsystem. The two sets of four stages of the pre-fdter are designed to remove sediments,
silts, and particulate of matter from the water. The pre-filters equally protect the
membrane filters from damage while removing all before water goes to the membranes.
In addition to the manufacturer filters replacement guidance, the pre-filters are replaced
when 10-15 psi differential exists between the two pre-filters (AXEON 2016).
61
Figure 22. Physical Decomposition Level Two for the Pre-Filter Assembly
5. Membrane Subsystem
Figure 23 illustrates the physical decomposition level two for the membrane
subsystem. The membrane subsystem consists of membrane element, permeate, and
pressure vessel. There are 10 membranes, two membranes per vessel for the size of 4040
PPM. The system has a 56% standard recovery rate and nominal salt rejection rate of
98.5%. Membranes allow water to pass through while filtering the residual contaminants
that may have been missed by the pre-filter. The membrane elements are preloaded with
Polyamide Thin Film Composite (TFC) HFl High-Flow-Low Energy membrane. The
membrane subsystem is important in removing organic substances colloid and bacteria in
water. Production rate and recovery rates are based on feed water conditions of 550 PPM
TDS at 77 degrees, 8.25 PPM of product TDS and other test parameters. However, the
treatment ability of the water system is based on feed water quality obtained from the
borehole. High TDS and/or low temperature will significantly reduce potable water
production.
The total concentration of TDS that are “rejected by the membrane is expressed as
a percentage” (AXEON 2013). Eor example, the nominal rejection rate of the membranes
as specified by AXEON is 98.5%. This means that about 98.5% of the dissolved solid
62
will not be able to pass through the membrane filters. The system is eapable of rejeeting
up to 98.5% Sodium Chloride (NaCl). Pereent rejeetion of the membrane is ealeulated in
order to validate the speeified pereent rejeetion TDS in the membrane filter.
% Rejeetion = (Feed TDS - Produet TDS)/ (Feed TDS) x 100% (1)
= (550 ppm - 8.25 ppm)/ (550 ppm) x 100% = 98.5%
Similarly, the amount of permeate water that is to be reeovered is also expressed
in pereentage. Aeeording to the manufaeturer’s speeifieation, the produet water flow rate
in eaeh membrane is 7.86 GPM while the feed water flow rate is 14 GPM. The pereent of
reeovery ean be ealeulated using the formula as shown.
% Reeovery = (Produet Water Flow Rate) / (Feed Water Flow Rate) x 100% (2)
= 7.86 GPM/14 GPM x 100% = 56%
Figure 23. Physieal Deeomposition Level Two for the Membrane Subsystem
63
6 .
Post-Filter Subsystem
The water system is eonfigured with two 10-micron carbon block and two-micron
ultra-pure post filters at the final stage of water purification process prior to disinfection
of the water. This configuration is to filter impurities or contaminants in the water before
consumption. The post filters are designed to remove chlorine particles and pesticides to
improve the taste and odor of the water. Figure 24 shows the physical decomposition of
the post filter subsystem.
Figure 24. Physical Decomposition Level Two for the Post Filter Subsystem
7. Tank Subsystem
There are three storage tanks to be incorporated to the water system: Non-potable
Water Tank, Rain Water Ta nk and Potable Water Tank. The physical decomposition of
the tanks is shown in Fig 25. Each of the tanks will hold up to 10,000 gallons of water.
The rainwater tank is incorporated to maintain the cost effective target of the IBWS and
to minimize frequent replacement of the water filters. The rainwater tank is used to catch
rainwater during rainy season. Both rain and borehole water are pumped through the
water purification system. The rainwater will serve as a substitute to the borehole water
and used most of the time during rainy season between the month of April and October
64
each year. The non-potable water ta nk serves as a temporary storage tank for the borehole
water prior to purification. Water is pumped to the tank twice daily. Non-potable water
runs through the purification system with the help of force of gravity and water pressure.
The potable water tank is designed to keep water pressurized in tank when it is
full. An automatic water shut off valve (SOV) is fitted to close and stop water from
entering the membrane. As water is being drained from the potable water tank due to
usage, the pressure in the tank will drop. The SOV will then open and allow water
through the membrane while the contaminated wastewater is diverted down the drain. A
check valve will prevent the backward flow of treated water from the potable water
storage tank to prevent the membranes from being ruptured.
Figure 25. Physical Decomposition Level Two for the Storage Tanks System
8. Disinfection System
The final stage of the water purification process is disinfection. Ultraviolet
disinfection system is a cost effective and environmentally friendly process of removing
99.99% of harmful waterborne microorganisms. It is designed to use a UV light to
disinfect the purified water that flowed through the post-filtration subsystem. This system
disinfects water without adding or taking minerals away from the water.
65
B. WATER SAMPLING ANALYSIS
An effective water sampling procedure involves ensuring that the installation of
the water purification components during maintenance are properly sanitized and flushed.
Proper maintenance would help trace water contamination once water does not meet the
PH requirements in accordance with WHO’s regulations. Figure 26 shows the water
sampling logic diagram. One must first monitor the water by taking water samples once it
completes the cycle in the disinfection system. The PH indicator will show whether the
PH values of the water is within the range of 6.5-8.5. If the water meets the PH
requirement, the quality of the water is good for consumption and meets the drinking
water requirement.
The purified water that do not meet the drinking water requirement may be
adequate to be used in industries or irrigation purposes without being treated. In the event
that the drinking water does not meet the PH requirement, it is imperative to identify the
source of contamination to ensure that the water system is free from contamination. Upon
determination of source of contamination, strict strategies will be implemented to prevent
the introduction of contaminants to the water system. Drinking water quality will require
further treatment by recycling the water through the water system to repeat the sampling
process.
66
Figure 26. Water Sampling Logie Diagram
C. WATER PURIFICATION SYSTEM PHYSICAL MODEL
As the Navy focuses on better cost-effective ways to develop systems that are to
fulfill the capability gaps of already existed systems, there is need for an operational
prototype to ensure that the proposed design will be feasible. The first component of this
process is to build a scale prototype to represent the feasibility of the water purification
system design. The main objective of an operational model is to ensure that the features of
the system that is being designed is going to influence the proposed design. For the purpose
67
of this thesis, the author used some COTS eomponents and assembled an operational model
of the water system, whieh serves as a foundation for the design of the main model.
1. Model Development and Implementation
In the operational analysis seetion of this thesis, an operational eoneept diagram
was introdueed to show the proposed eoneept of the water purifieation system. This
model development was influeneed by system operational eoneept and the bloek diagram
of water purifieation model in Figure 27. Turning to the diseipline of the operations
analysis, the model guided the operation of the prototype. The model illustrates the
operational sequenee during water purification. The water from the non-potable tank or
rainwater ta nk is pumped after being passed through the detection and monitoring
system. Water flows through each of the two stages of the pre-filter subsystem. Once the
pre-filtration is completed, the water then pushed through each of the membrane filters
and finally to the storage tank. From the storage tank, the water makes one more loop
through the post-filter assemblies and then to the faucet.
To faucet
2.0
3.0
4.0
5.0
PRE-SEDIMENT
PRE-CARBON
MEMBRANE
POST CARBON
FILTER
FILTER
FILTER
FILTER
1.0
WATER SOURCE
6.0
STORAGE TANK
Figure 27. Block Diagram of Water Purification Mode Prototype Model
Using the model in Figure 27 as a reference, the prototype model was assembled
using Philip screwdriver, small knife, and Teflon tape. The prototype model is a four
stage, point-of-use water purification system with a flow rate of 50 GPD. The four stages
are incorporated with sediment pre-filter, carbon pre-filter, membrane filter, and carbon
68
post-filter. Its dimensions are 17” L x 12” W x 4” D with a 3.2-gallon capacity storage
tank. The prototype water purification system parts list is shown in Table 12.
Table 12. Prototype Water Purification System Parts List
FILTER/MEMBRANE
Part Number
Sediment Pre-Filter
Q5605
Carbon Pre-Filter
Q5633
Carbon Post-Filter
Q5633
Membrane Filter
TQ56-35FC/NSF
Figure 28 shows the prototype water purification system. The components of the
system influence one another in the context of system integration. The results gathered
from the test, operation, and evaluation of the prototype will form the basis for
development of the water purification system in the areas of design for reliability,
maintainability, and supportability.
2. Operational Test and Evaluation
The purpose of operational test and evaluation (OT&E) is to “faeilitate the
necessary validation of the system configuration to provide assurance that it will meet the
specified requirement” (Blanchard and Fabrycky 2011, 164). The high-level user
requirements of the water purification system are for the system to be able to monitor,
filter, purify, disinfect, and store potable water. These high-level user requirements are
the capabilities of the water purification system the author intend to validate during the
OT&E process. The water system prototype OT&E will follow further steps and
processes to ensure that the system configuration meets the high-level operational
requirements specified during the conceptual design phase.
For this OT&E of the water purification system. Type 2 testing process was used.
Type 2 testing is the “activity associated with the initial qualification of the system for
operational use” (Blanchard and Fabrycky 2011, 169). Type 2 testing is adopted because
COTS do not require much testing but must be validated to ensure that they are
compatible when integrated with other components (Blanchard and Fabrycky 2011). Two
individual tests that are tailored to the user need are identified: Components performance
test and personnel test and evaluation. Performance tests will verify individual system
performance characteristics of the water purification system such as the production rate,
water flow, and performance of system components. Personnel testing and evaluation
will verify the interface between the operators and water purification system.
Additionally, it will verify skills, training and time required to perform maintenance.
Table 13 shows the OT&E validation checklist.
Table 13. OT&E Validation Checklist. Adapted from ESP
Water Products (2016).
Task
Number
Item
Functions (SV-4)
1
Evaluation of high-level requirements
(Monitor, Filter, Purify, and Store
water)
2.0, 3.0, 4.0, 5.0
2
Verify technical data accuracy (Flow
Rate, Production Rate)
1.0
70
Task
Number
Item
Functions (SV-4)
3
Evaluation of water system component
performance (Output)
2.0,3.0,4.0,5.0
4
Verify personnel skill-level with system
(Easy to Use, Maintenance Concept)
N/A
5
Verification that user needs are met
N/A
3. Pre-Water Treatment Test Analysis
Prior to activating the water purification system, the author tested the tap water
obtained from the sink of his kitehen to determine the water condition. The conditions
stipulated by the manufacturers for the operation of the membrane with thin film
eomposite (TFC) are summarized in Table 14.
Table 14. Conditions for Operation of TFC Membrane.
Adapted from ESP Water Products (2016).
Source Water Supply-TFC
Community/Private
Bacteriologieally Safe
System Pressure min/Max
30 to 100 psi
Temperature
40 to 100 degrees
PH Range
3.0 to 11.0
Maximum Supply TDS Eevel
2000 mg/L
Turbidity
<1.0 net turbidity (NTU)
Chemical
Parameters- TF C
Hardness (CaC03)
<350 mg/L (<20 gpg)
Iron (Fe)
<0.1 mg/L
Manganese (Mn)
<0.05 mg/L
Hydrogen Sulfide (H2S)
0.00 mg/L
Production Rate
Efficiency Rate = 12.1%
Pereentage of the available water to the user as
the system treats water under operating
conditions daily.
Recovery Rate = 21%
Percentage of water to the membrane that is
available to the user as the system treats water
without a storage tank.
Daily Production Rate = 50 GPD
71
The author ensured that the tap water being used was baeteriologieally safe prior
to running the system by performing a bacteria test. A bacteria vial was set upright on the
kitchen counter and carefully filled it with water at 5 ml line. The cap was replaced and
tightly covered to prevent leakage. The vial was shaken vigorously for 20 seconds and
then placed upright in a cool dry area of a temperature between 70 to 90 degrees for 48
hours (BRK Brands 2005). After 48 hours, the vial was observed to determine its color.
For this test, purple color showed negative result indicating that no bacteria were detected
in the water. Yellow color would show positive result indicating a chance that harmful
bacteria were detected in the water (BRK Brands 2005).
Next, the author performed the lead and pesticide test to determine if there are
presence of dissolved lead at levels below the Environmental Protection Agency (EPA)
recommended action level of 15 parts per billion (ppb) (BRK Brands 2005). The
Pesticides Test is designed to detect pesticides like atrazine and simazine below the EPA
Maximum Contaminant Eevel of 3 ppb and 4 ppb respectively (BRK Brands 2005). A
dropper from the test kit was used to place two dropper-full of water sample into the test
vial. The water droplets were shaken for 2 seconds and placed on the kitchen counter.
Both test strips for lead and pesticides were placed into the test vial for 10 minutes with
their arrows pointing DOWN. After 10 minutes, the test strips were taken out of the vial
to read the results. The bottom line (next to the number, 1) appeared darker than the top
line (next to the number, 2). The bottom line appearing darker than the top line is a
negative test result, which indicates that the water has neither dissolved lead nor
pesticides. Positive test would have shown the top line of the test strips (next to the
number, 2) darker than the bottom line (next to the number, 1), or both lines being dark
indicating presence of dissolved lead and pesticides in the water.
Once the lead and pesticides tests were conducted, the author tested for total
nitrate/nitrite, nitrite, hardness, total chlorine, free chlorine, bromine, PH, and total
alkalinity of the water. Eor the nitrate/nitrite test, the reagent pad was placed into the
water sample for two seconds and was removed. After one minute, the color of test strip
changed and was matched to the color chart. The test result of the total nitrate/nitrite and
nitrite showed 5.0 ppm and 0 ppm indicating below acceptance level. Other tests were
72
completed by immersing the test stripe in the water sample and immediately removed it.
Test strip was held for 15 seeonds and then matehed to the eolor ehart. The tests and
results are presented in Table 15. The author observed that the tap water total hardness
indieated 425 ppm, whieh is mueh higher than the <50 ppm drinking water requirement.
Furthermore, the PH value was at 8.5 ppm, whieh is within limit of WHO but high. The
total alkalinity of the tap water showed a very high value of 180 ppm more than the
aeeepted value of <120 ppm for drinking water. Other tests sueh as baeteria, lead,
pestieides, total nitrate/nitrite, nitrite, total ehlorine, free ehlorine, and bromine were low.
Table 15. Tap Water Pre-Treatment Test Result
Test
Desired Values
Results
Note
Baeteria
None
Purple
Negative
Lead
<15 ppb
1 ppb
Low
Pestieides
<3 ppb atrazine; <
simazine
1 ppb
Low
Total Nitrate/Nitrite
<10.0 ppm
5.0 ppm
Low
Nitrite
<1.0 ppm
0 ppm
Low
Total Hardness
<50 ppm
425 ppm
Very High
PH
6.5-8.5 ppm
8.5 ppm
Very High
Total Chlorine
<4 ppm
0 ppm
Very Low
Free Chlorine
<3 ppm
0 ppm
Very Low
Bromine
<4 ppm
0 ppm
Very Low
Total Alkalinity
<120 ppm
180 ppm
High
4. OT&E Procedure
Prior to the assembly of the model, the author verified all eomponents to ensure
they are the right parts and in proper eonfiguration. All parts of the system prototype
model were assembled using simple tools as speeified by the manufaeturers. For easy
identifieation of the model eomponents, all water tubing was labeled and eolor eoded.
Figure 29 shows the assembly and eonfiguration of the prototype model. The feed water
valve was eonneeted to the pre-filter using a 1/4” red tubing. The feed water tubing
eonneets from the eold water hose to the pre-filter. A 1/4” blaek tubing eonneets the
membrane drain port to the sink drain port. From the membrane produet port, 3/8” blue
73
water tubing connects to the storage tank. The post-filter was then connected to the faucet
using a 3/8” black tubing as shown in Figure 29. The faucet will be used to obtain potable
water from the storage tank.
Prior to activating the system, all the supply and drain lines were checked for leak
and ensured they are secured. The water flow valve was slowly turned ON while the
storage tank valve was turned one quarter turn counterclockwise to open the valve. The
water faucet was opened for the product water to flow until all the air was expelled. Once
the air was expelled from the system, the product water faucet was closed. The storage
tank was allowed to fill up within 4 hours and the water was dispensed to drain twice
(ESP Water Product 2016). This process was performed in order to clean the storage ta nk
from the factory installed sanitizing solution.
From membrane to storage
tank
L-R: Pre-Filter, Carbon-Filter, Membrane,
Post-Filter
Storage T ank
Test Stripe
From membrane drain
port to sink drain line
From water source
to pre-filter
From post-filter to
faucet
Figure 29. The Water Purification System Prototype Model Configuration
74
While the system was running, the author evaluated the high-level operational
requirements of the system by cheeking each component to ensure that they are operating
as specified by the manufacturers. There were no interruptions of the water flow in each
of the filters. Although the water purification design called for an automatic monitoring
system to monitor the presence of bacteria and chemical compound in the source water
supply, however, the model is not incorporated with this system. The monitoring of the
tap water was demonstrated using test strips. The model was able to fdter, purity, and
store potable water of about three gallons. The faucet was turned ON most of the time the
evaluation showed that the model produced about two gallons of water within
approximately three hours of operation. Therefore, with continuous use of the water from
the storage tank throughout the day, the model prototype will have produced about 48
gallons of water.
With the completion of the evaluation of the high-level system operational
requirements and technical data accuracy, the author performed a post-test of the treated
water to determine if there are significant difference in values between the pre-treated
water and the treated water. For the purpose of this thesis, the test results that were within
limits were repeated to see if there may be any decrease in the values obtained. The water
sample tests were repeated as in paragraph three above. The post water-treatment test
results are compared to the pre water treatment results, as shown in Table 16.
Table 16. Comparison of Pre and Post Tap Water Treatment Test Results
Test
Desired
Values
Results
Notes
Pre-Test
Post-Test
Pre-Test
Post-Test
Bacteria
None
Purple
Purple
Negative
Negative
Lead
<15 ppb
1 ppb
Oppb
Low
Low
Pesticides
<3 ppb
atrazine & <
simazine
1 ppb
Oppb
Low
Low
Total Nitrate/Nitrite
<10.0 ppm
5.0 ppm
1.0 ppm
Low
Low
Nitrite
<1.0 ppm
0 ppm
0 ppm
Low
Low
Total Hardness
<50 ppm
425 ppm
30 ppm
Very
High
Low
PH
6.5-8.5 ppm
8.5 ppm
7.0 ppm
Very
Low
75
Test
Desired
Values
Results
Notes
High
Total Chlorine
<4 ppm
0 ppm
0 ppm
Very Low
Very Low
Free Chlorine
<3 ppm
0 ppm
0 ppm
Very Low
Very Low
Bromine
<4 ppm
0 ppm
0 ppm
Very Low
Very Low
Total Alkalinity
<120 ppm
180 ppm
80 ppm
High
Low
CONTAMl
INATED WATER TEST (]
Mixture of fertilizer and dirt)
Test
Desired
Values
Results
Notes
Pre-Test
Post-Test
Pre-Test
Post-Test
Total Nitrate/Nitrite
<10.0 ppm
<12 ppm
10.0 ppm
Very
High
High
Nitrite
<1.0 ppm
<3.0 ppm
1.0 ppm
Very
High
High
Test result showed that the tap water total hardness decreased to 30 ppm and
below <50 ppm drinking water requirement. Furthermore, the PH value was at 7.0 ppm,
which is within the acceptable limit of WHO. The total alkalinity of the tap water showed
a low value of 80 ppm lees than the accepted value of <120 ppm for drinking water.
Other tests such as bacteria, lead, pesticides, total nitrate/nitrite, nitrite, total chlorine, free
chlorine, and bromine were low as shown in Table 16.
Further test was conducted using a discolored water that was contaminated with
dirt and fertilizer. During this test, there was no pump available to pump the
contaminated water through the water purification system. The author poured the
contaminated water through the red tubing to the pre-filter as shown in Figure 29 and
then connected the tubing to the tap water. The red tubing was connected to the tap water
to lower the TDS of the feed water. The author noticed that high TDS significantly
reduced water purification and the total nitrate/nitrite and nitrite appeared high but within
the EPA maximum contaminants level standard of <10 ppm and <1.0 ppm respectively as
shown in Table 16.
Clearly, the comparison of the two water samples showed that the water that was
run through the water purification system indicated decrease in values. This means that
the water-purification prototype model is effective, efficient, and able to fill the capability
76
gaps in the area of monitoring ehemical compounds, filtering water, purifying water, and
storing potable water.
The maintenance skill level needed for the water system prototype model is
simple hands-on maintenance. Removal and replacement of the filter elements is easily
performed by hand and requires about five minutes to complete. Additionally, routing of
the color-coded tubing took about three minutes to complete. It is not expected that the
actual water purification system maintenance is the same as the prototype model;
however, the author expects that maintenance requirement of the actual system should
not take more than one hour. From this evaluation of the personnel skill-level with the
prototype model, the author concludes that it is adequate.
Finally, the objective of the prototype model was met. The test and evaluation of
the prototype provided good feedback on how well the system will perform in its
operating environment and to identify any problem that was detected. The system
performance was adequate and there were no corrective action or modifications required.
The prototype model for OT&E to this point proved that the system is expected to meet
user needs as specified.
D. SYSTEM RELIABILITY ANALYSIS
The water purification system will use backup components to create redundancy
and improve the reliability of critical functions. Reliability is the measure of the “ability
of a product or part to perform its intended function under a prescribed set of conditions”
(Kumar et al. 2006). In order to analyze the reliability of the water system, basic
reliability terms are defined in Table 17. In system engineering process, reliability
prediction is very important in the “Design for Reliability process during the system
development stage” (Crowe and Feinberg 2001). Predicting the reliability of any system
will “provide an early estimate of the design complexity that relates to the product
reliability” (Crowe and Feinberg 2001).
77
Table 17. Definition of Basic Reliability Terms. Adapted from Kumar et al.
(2006).
TERMS
DEFINITIONS
Availability
The fraction of time a piece of equipment
or a repairable product is expected to be
available for operation.
Mean Time to Failure (MTTF)
The average length of time before failure of
a product or component.
Mean Time Between Failures (MTBF)
The average time from the up time after the
repair following a failure to the next failure.
Mean Time to Repair (MTR)
The average length of time to repair a failed
item.
Redundancy
The use of backup components to increase
reliability.
Failure Rate
The rate at which failure occur in a
specified time interval (Number of failures
divided by total operating hours).
1. System Overall Reliability Model
The high-level objective of this thesis is to show that the Improved Borehole
Water System is affordable, easy to maintain, and easy to operate without the need for a
continuous electrical power; the complete reliability model of the water system is shown
in Figure 30. Figure 30 shows a set of two pre-sediment filters and pre-carbon filter are in
parallel configuration with another back-up set of pre-filter sediment filter and pre-carbon
filter respectively. A switch is added between the monitor/detector system and each set of
pre-sediment and pre-carbon filters. The switch will automatically transfer the operation
of one set of pre-sediment and pre-carbon filters to the similar backup pre-sediment and
pre-carbon filters in the event of failure as shown in Figure 30.
The water purification system has six membrane filters that are connected in a
parallel network as shown in Figure 30. The membrane filter element will continue to
operate regardless of damage to any of the membranes. As in pre-filters, a set of post¬
carbon and post-ultrapure filters are in parallel configuration with another set of back-up
post-carbon and post-ultrapure. A switch was installed between the storage tank and the
set of post-carbon and post-ultrapure filters to automatically transfer the system operation
to the backup components in the event of failure. The backup unit will not operate until
78
the failure sensor reeognizes of a failure in the operating set of eomponents and
automatieally switehes operation to the standby unit.
AlfTOMATlC SHUT OFF VALVE
— >
5.0
PRE-SEDIMENT
FILTER
1
$.1
PRESEDIMENT
FILTER
5.2
PRE-CARBON
FILTER 1
4.0
MONlTORmETECTOR h
SYSTEM
5.3
PRE-CARBON
nLTER2
6.1
MEMBRANE
FILTER
6.2
MEMBRANE
FILTER
6.4
MEMBRANE
RLTER
6.5
MEMBRANE
FILTER
FLOW
RESISTOR
FLOW
RESISTOR
FLOW
RESISTOR
7.0
STORAGE
WATER TANK
3.0
BOOSTER
PUMP
1.0
WATER
SOURCE
Non-Potabl« Water Tank or
Rain Water Tank
2.0
POWER
SOURCE
9.0
DISINFECTION
SYSTEM
8.2
8.0
POST ULTRA
<-
POST CARBON
PURE FILTER
FILTER
4
8.3
POST ULTRA
<3 —
8.1
POST CARBON
PURE FILTER
FILTER
- 0 '
Figure 30. Water System Reliability Model
The eomponent redundancy of the water system is of standby type and not
designed to operate together with other components. It is the author’s opinion that a
standby redundancy would be better for the design to reduce wear and tear of components
and unnecessary parts replacement.
The author worked as the Auxiliaries Mechanical and Assistant Chief Engineer
Officer aboard an FFG-7 Class frigate. With his experience of the past design of water
purification products that were used aboard the FFG-7 Class frigate, it is the author’s
belief that the design of the system components of the MROS is very similar to the design
that was used aboard the vessel. Therefore, it is assumed that the reliability of the filter
elements and their housing would be similar to the other products. According to the
component manufacturers, each of the pre-sediment, carbon, and ultrapure filters are
79
expected to be replaced after every year at 8,640 hours (AXEON 2013). This operating
hours of the filters is obtained based on the annual replacement frequency of the filters.
Similarly, each of the membrane filters is expected to be replaced biennially at 17,280
hours. The operating hours is based on the manufacturer’s recommended biennial
replacement of the membrane filter elements (AXEON 2013).
Unfortunately, the reliability of these components is not known, but it is
obviously high based on the author’s experience aboard an EEG-7 Class frigate, which
has similarly water purification system. Meanwhile, for the sake of analysis, the author
predicted that the reliability of each pre-sediment, carbon, and ultrapure filter is 0.98
while the reliability of each of the membrane filters is 0.99 based on his experience of a
similar water purification system. Although the water pump is highly reliable, there will
be a spare pump to be used in the event the pump in operation breaks down. Emergency
generator and city electricity (if available) is available to be used as a back-up power
supply should the solar power becomes unavailable. The reliability of the power, pump,
monitor/detector, all storage tanks, and disinfection system are assumed to be 0.99, 0.99,
0.98, 0.99, and 0.99 based on the author experience on a similar water purification system
aboard EEG-7 Class frigate. Given the operating hours of the pre-filters and post-filters,
each has a failure rate of 0.0001 failure/hour (1/MBTE). All membrane elements failure
rate is 0.00005 failure/hour (1/MTBE).
With the incorporated redundancy to the system design, the overall reliability of
the water system can be estimated. It is predicted that standby redundancy will have
higher reliability than the operating redundancy. Eigure 31 illustrates a series network
reliability block diagram (RBD) for the non-potable water tank, rainwater tank, power
system, pump system, and monitor systems. The systems are in series and must operate in
a satisfactory manner for the water system to function properly. The systems reliability is
the product of the reliability for the individual system expressed as:
R ~ (.^NPWtank) (.^RWtank) ( ^POWEr) {Rpump) (.^M/d) (3)
R = (0.99) (0.99) (0.99) (0.99) (0.99) = 0.9509
80
Figure 31. RBD of Non-potable tank, Rain water tank, Power, Pump, and
Monitor Systems
Next is the set of pre-sediment and pre-carbon filters. Each set is in series and
have a parallel standby connection as shown in Figure 32. The reliability of the set of the
pre-filter subsystems in operation is calculated as shown.
i Rps) (.Rpc) (4)
R = ( 0.98) (0.98) = 0.9604
To determine the reliability of the standby system, the standby system follows the
Poisson distribution “because standby systems display the constant At characteristics of
this distribution” (Blanchard and Fabrycky 2011, 397). As shown in Figure 32, there is
one set of operating subsystem and one set of identical standby. It is assumed that the
reliability of the switch is 100%. Recall that each of the pre-filters are expected to operate
over t = 8,640 hours with a failure rate (A) of 0.0001 failure/hour (1/MTBF).
Figure 32. RBD of the Pre-filters
The reliability of the set of standby subsystem (pre-sediment and pre-carbon
filters) is estimated as shown. The probability of no failure is represented by the first
81
term, e~At; the probability of the one failure is and so on. In the eonfiguration
of Figure 32, it is expeeted that one failure will oeeur with one subsystem in fully
operational eondition.
P (One set Standby system) = e~At + (5)
R= e-(0.0001)(8,640) + (0.0001)(8,640)e-(0.0001)(8,640)
= 0.4214 + 0.3641 = 0.7856
The ealeulation shows that the standby system of the pre-sediment and pre-earbon
filters have reliability of 0.7856. With this value, both the operational system and the
standby system overall reliability of the pre-filters as shown.
^ “ (1 “ Rpspc) (1 “ ^standby) ( 6 )
R = 1 - (1 - 0.9604) (1 - 0.7856) = 0.9912
The earlier predietion that the standby system has higher reliability than operating
redundaney ean be validated. Assuming that the design was for the operating redundaney
and the subsystems are operating throughout the purifieation period. The reliability of the
eonfiguration is determined as shown.
R=1-(1-R)2 (7)
R = 1-(1 - 0.4214)2 = Q 5552
As predieted, the reliability of the standby system is higher (0.9912) than the
reliability of the system using operating redundaney (0.6652).
The six identieal membrane elements are in parallel. All the membranes must fail
to eause total system failure. The parallel network of the membrane elements is shown in
Figure 33. The eomponent reliability is ealeulated as shown. The reliability of the storage
tank is assumed to be 0.99.
R = 1 - (1 - Ri) (1 - R2)(1 - R3)(1 - «4)(1 - RsXl - Re) (8)
R = 1 - (1 - 0.99) (1 - 0.99)(1 - 0.99)(1 - 0.99)(1 - 0.99)(1 - 0.99)
= 1.00
82
The overall reliability of the membrane elements is approximately 1.00.
Figure 3 3. RBD o f Membrane Elements
For the post-filters reliability, the same ealeulation that was made for the
reliability of the pre-filters are repeated for the post-filters and the same results were
obtained sinee they have similar failure rate and MBTF. As shown in Figure 34, there is
one set of operating subsystem and one set of identieal standby. It is assumed that the
reliability of the switeh is 100%. Reeall that eaeh of the pre-filters are expeeted to operate
over t = 8,640 hours with a failure rate (1) of 0.0001 failure/hour (1/MTBF).
Figure 34. RBD of the Post-Filters
The standby system follows the Poisson distribution “beeause standby systems
display the eonstant At eharaeteristies of this distribution” (Blanehard and Fabryeky 2011,
397). The reliability of the set of standby subsystem (pre-sediment and pre-earbon filters)
is ealeulated as shown. The probability of no failure is represented by the first term,
83
e~2.t; the probability of the one failure is and so on. In the configuration of
Figure 34, it is expected that one failure will occur with one subsystem in fully
operational condition.
P (One set Standby system) = e~At + (9)
R= e-(0.0001)(8,640) + (0.0001)(8,640)e-(0.0001)(8,640)
= 0.4214 + 0.3641 =0.7856
The calculation shows that the standby system of the pre-sediment and pre-carbon
filters have reliability of 0.7856. With this value, both the operational system and the
standby system overall reliability of the pre-filter as shown.
R — 1 (1 Rpspc) (1 ^STANDBY ( 10 )
R = 1 - (1 - 0.9604) (1 - 0.7856) = 0.9912
Therefore, the overall reliability of the water system was estimated as shown.
^Water System =
(.Rnpt,rwt,pwr,p,m ) (Rp
re-filter^C.^Membrane^(.^Tank)C.^Post-filter^(.^Disinfectant) ( 11 )
Rwatersystem= (0.9509) (0.9912)(0.9900)(0.9900)(0.9912)(0.9900)
= 0.9064
From the reliability analysis, the estimates show that the water purification system
is highly reliable as most of the components are redundant. The water purification system
will perform its tasks 90% of the time during operation. This means that the probability
that the water system will accomplish water purification in a satisfactory manner under
spcified operating condition is 90%.
84
2. Fault-Tree Analysis
Fault-tree analysis focuses on different ways in which a specific water
purification system failure can occur, and the probability of its occurrence is presented.
The water system fault tree helps to identify the undesired outcome or event that may
occur while the system is in operation and then determines what event or combination of
events could cause the desired event (Ball 2003).
Figure 35 illustrates the fault tree analysis of the water system. The top level
event failure is the loss of water production and its causal hierarchy in the form of a fault
tree is shown. The loss of water production occurs when the water system cannot pump
water, water tank is empty, and loss of water pressure in the membrane. As indicated in
the diagram, the system will lack pump capability when the pump is damaged, no power
availability, or no feed water in the water pump. The inoperability of the pump refers to
the failure of one or more internal parts in the pump system. Similarly, the pump does not
turn ON without feed water running through it. Additionally, the pump is operated by
electricity and will not turn ON without electrical power.
While faulty pump causes loss of water production, lack of water in the non-
potable water tank could be a causal effect to the loss of water production. The source of
water that runs through the water system comes from the potable water tank or rainwater
tank. Inoperability of the water pump will interrupt water production due to empty water
tanks.
Lack of water pressure in the membrane will result in slow or interruption of the
water production process. Pressure drop in the water system may be due to change in
pressure in clogged filters. Filters may clog when the pre-filters are not working in
accordance with specification. Filters may also clog when adequate filter maintenance
was not performed at the due dates. Dirty filters will prompt the change in differential
pressure (Delta-P) to pop. Delta-P is a red button mechanism in the water filter, designed
to pop-out when the filters need replacement or certain maintenance. The popping of
Delta-P push button indicates that the filters need replacement. This indication slows or
stops water production until the filters are replaced.
85
The best way to improve the reliability of the water system to ensure that water
produetion is not interrupted is to have a spare water pump. The spare pump will be used
immediately the pump in operation is not available. There are two redundaneies for
power supply. The emergeney generator or the eity eleetrie supply will be used when the
solar power is unavailable. Furthermore, the membranes will be inspeeted daily during
seheduled down time maintenanee to ensure that Delta-P push buttons do not indieate
that the filters require replaeement. Clogged filters will be replaced with new filters to
avoid interruptions of water production.
Figure 35. Fault Tree Analysis of the Water System
E. INTEROPERABILITY REQUIREMENTS
Interoperability of the water system was defined during the conceptual phase of
the system design. The water system is designed to be able to interface and work with the
external systems to achieve the objective of the purification process. Interoperability of
the water system includes systems, subsystems, process, procedures, organizations, and
objectives over the life cycle. As shown in the interoperability diagram of Figure 36, each
external system and water system subsystems interface with one another in order to
enhance the purification process. Each component has a part to play during the water
purification cycle.
86
From a systems engineering perspeetive, interoperability of the water system was
evaluated during the requirement development, design verifieation, and T & E
verification. Each of the evaluation of the water system showed that the system is able to
operate successfully with the interface of other external systems. In the life cycle
management perspective, continuous on-job training of the technicians and the
maintenance processes of the water system shows interface of the system and the
maintainers. Technicians will conduct pre-operational inspection, post-operational
inspections, daily and turn-around inspection, and removal and replacement of
components.
Spare parts are ordered through the military stock system by interfacing with the
dealers or manufacturers supply system. The system’s user and the parts dealers will
continue to correspond on the status of the ordered parts until it arrives. Upon parts
arrival, the maintenance personnel are informed and the replacement of the spare parts is
scheduled during the next down time. Clearly, the system’s interface from the time parts
are ordered, received, and performance of the maintenance is a procedural and
organizational interoperability of the water system.
Figure 36. Interoperability Diagram
87
F. OPERATIONAL USE AND SYSTEM SUPPORT
The system “maintenanee eoncept provides the foundation that enables the design
and development of the maintenance and support infrastructure and defines the specific
design-to requirements for the various elements of support such as test and equipment,
facilities, transportation, and handling equipment” (Blanchard and Fabrycky 2011, 95).
The maintenance concept of the MROS shall include maintenance levels, maintenance
support locations, frequency of maintenance, and environmental requirements. Supply
support is critically important in the life cycle of every system, equipment and
components. Supply support requirements for the system will be properly coordinated
and implemented once the system is in operation. Without supply support, the purpose of
the MROS will be crippled and the physical integration of the system components will be
affected.
The maintenance and support concept of the MROS was incorporate at both the
conceptual and detail design phases of the system to ensure that parts are readily
available for maintenance. The operating log of the water system must be maintained and
copies sent to the local parts support upon request in order to validate the manufacturer’s
warranty (AXEON 2013). The maintenance and support concept was developed in the
user need analysis section of the thesis, which evolved from the water systems
operational requirements definition. Figure 37 shows the system support and maintenance
flow diagram of the MROS. It is expected that the maintenance level for the MROS will
be primarily an organizational maintenance where the users are able to conduct pre-
operational checks, remove and replace components, conduct an on-site corrective and
preventive maintenance, and perform minor troubleshooting. The U.S. forces that operate
on the installation where the system will be installed shall be responsible for the
maintenance and custody of the system. The system manufacturers are to perform the
depot level maintenance such as overhaul, supply support, detail maintenance, and
rebuild of some specific components. Local parts supply facility will be utilized for onsite
maintenance, field shop activity, and supply support.
88
System Operations
OPERATIONAL SITE
Modified Reverse
Osmosis System
Organizational Maintenance t
-Operational Check \
Depot Maintenance
•Overhaul
-Supply Support
•Detail Maintenance
-Manufacturing
•Rebuild
•Remove & Replace
Component
- Minor Trouble Shooting
- On-site corrective and
Preventive Maintenance
-Supply Support
•Field Shop Facility
Local Parts Support
Manufacturer
Figure 37. System Operational and Maintenanee Flow. Adapted from
Blanehard and Fabryeky (2011).
From the onset of the system development, it is important to identify all of the
jobs that are neeessary in operation and maintenanee of the new system (Grady 2010).
Training and training support enable the system operators to learn how to maintain and
operate the new system. The training requirement and skills that will be eovered and
paekaged into eourses will be determined prior to integration of eomponents (Grady
2010). The system users are to be trained and reeeive hands-on instruetions by the system
manufaeturers to perform basie maintenanee proeedures. The water system will not
require daily maintenanee; meanwhile, demand for spare parts may be low due to the
seheduled replaeement of filter elements in aeeordanee with the manufaeturers’
guidelines. There will be no queue length while waiting for designated quantity of spare
parts. Onee a eontraet is made to develop a eomponent for the water system, there will be
time limit the produet must be produeed, tested, and shipped. Manufaeturing lead time
(MLT) will be established and adopted at the time of the eontraet to ensure that all hands
are on deek.
Produeing the water system eomponent will require a eoordinated set of aetivities
that are repeated over time and reduee the overall time in manufaeturing proeess. Delays
in manufaeturing of eomponents or parts will ereate a major setbaek in the system
integration. In order to avoid sueh delays, there will be direet eontaet with the
89
manufacturers to know status of all the eomponents ineluding the estimated time
produetion would be eompleted. Both the requirements for produeibility and logistics will
be closely coordinated to avoid parts delivery delays. Just-in-time manufaeturing will be
adopted by the manufaeturers to ensure that produets are produeed and shipped early to
the eustomers.
Aeeording to the manufacturer’s guidelines, the sediment and carbon filters are to
be replaeed every 12 months while the membrane filters will be replaeed every 24
months. Unseheduled repairs are to be eondueted in aecordance with the maintenanee
instruetional manual provided by the system manufaeturers. Pre-expended bins for
eonsumable parts will be available for the users to store on hand spare parts. Components
spare parts will be eonstantly supplied by the loeal supply support faeility throughout the
life cyele of the water system. As stated in the operational requirement seetion, the
system will not be affected by the environment where it is to be operated. Although the
system will not be effieient in water production at low temperatures, this coneem will not
be a problem in West Africa as the temperature do not drop below 60 degrees.
Environmental shoeks and vibration will not affect the system beeause earthquakes are
not eommon in its operational environment.
90
V. CONCLUSION AND RECOMMENDATIONS
A. CONCLUSION
The main objective of this research was achieved. The objective to incorporate a
purification system to the BWS design to improve its capability for the local population
as well as U.S. forces that will operate in West Africa was met. This thesis showed as a
proof of concept of the feasibility of adding a purification system to the borehole water
system. The research concludes that MROS would provide quality water usable to the
local population and U.S. forces that will operate in West Africa in the future.
From Chapter I, recall the research questions that were posed;
(1) What modifications need to be made to the existing West African borehole
water system (BWS) to make potable water?
(2) What water purification system can be incorporated with BWS to provide
cost-effective and safe water to U.S. forces operating in West Africa?
(3) Would the water purification system be operationally feasible, technically
feasible, and cost-effective for U.S. forces operating in West Africa?
To answer research question 1, Chapter I of the thesis discussed and established
the user needs during the conceptual design and analysis phase of the water purification
system. From the author’s experience of having lived and grew up in Nigeria, West
Africa, he discovered that the current borehole water system needs a purification system.
The study on the quality of the borehole water in West Africa showed that dependency on
the naturally filtered ground water is not sufficient for human consumption. The presence
of metal compound and bacteria in the borehole water indicate a need for purification
system. Therefore, BWS needs a purification system that will close the capability gaps in
the area of monitoring presence of metals in the water, filtration, purification, and
disinfection of potable water before use.
In Chapter III, the feasibility study demonstrated the selection of the MROS as the
preferred water system that would be used to fill the capability gaps in the area of
monitoring chemical compound, filtering, and disinfection of water. The Pugh Matrix
91
method was used to determine the alternative water system. However, the most desirable
funetional areas of the water system that were investigate are cost, production rate,
usability, and safety criteria. With the selection of the preferred water system, cost-
benefit analysis of the water purification system alternatives showed that the MROS is
cost-effective and safe to be used. This determination was based on the high-level
requirements of the water system. Therefore, the answer to the second research question
is yes, based on the author’s analysis. MROS can provide cost-effective and safe water to
U.S. forces operating in West Africa.
Chapter IV demonstrated the capabilities of the physical prototype model of the
water purification system. The test and evaluation of the prototype model showed that the
MROS met most of the operational requirements as specified during the conceptual
design phase of the system. The prototype is not incorporated with an automatic
monitoring system and disinfection system. The author used water test strips to
supplement the automatic monitoring system. The complete cycle of the operational
prototype model showed that the water purification was adequate. Comparing the PH
values of the water before and after the purification cycle, the two readings were
significantly different. The answer to the second research question is yes; the water
system is operationally feasible, technically feasible, and cost-effective for U.S. forces
operating in West Africa.
Furthermore, the water purification system will use backup components to
improve the reliability of its critical components. MROS proved that it has high reliability
as demonstrated in Chapter IV. The author used the water purification system aboard an
FFG-7 frigate as a reference due to its high reliability. The reliability percentage of this
water system components was assumed based on the operation of similar system aboard
an FFG-7 frigate. The water system component reliability ranges from 0.97 to 0.99.
Based on these reliability values, the author estimated the overall reliability of the water
system to be 0.9064. This means that the probability that the water purification system
will accomplish its operational tasks in a satisfactory manner for a given period is 90%.
92
B. RECOMMENDATIONS FOR FURTHER STUDY
The author recommends that further study of the borehole water system design
would contribute to a better understanding of the capability gaps that might be
incorporated during the design to prevent ground water contamination. Further research
should investigate the construction and design of the borehole system to determine
preventive measures to soil leach around the area of borehole location.
The author’s research is focus on borehole water purification; a future
recommendation is to research other ways to develop a system to clean contaminated
borehole water to meet the demand of clean water for consumers. Studies are to be
instituted to eliminate or reduce the products of water contamination that leaches into
ground water resource.
Remediation technology needs to be implemented to manage the causal factors
that introduce contaminants to the ground water. Finally, this thesis did not address risk
analysis of the effects of contaminants in the water to human beings. Attention should
focus on the borehole water system technology to determine preventive measures to be
installed in the suction and casing piping to minimize the effects of arsenic
polluted/contaminated ground water to human health.
93
THIS PAGE INTENTIONALLY LEET BLANK
94
LIST OF REFERENCES
Adelekan, B.A. 2010. “Water Quality of Domestic Wells in Typical African
Communities: Case Studies from Nigeria.” International Journal of Water
Resources and Environmental Engineering 2(6): 137-147.
http://www.academicjoumals.org/article/articlel379427860_Adelekan.pdf
Akudago, John, Larry Chegbeleh, Makoto Nishigaki, Nukunu Nanedo, Anthony Ewusi,
Kwabena, Kankam-Yeboah. 2009. “Borehole Drying: A Review of the Situation
in the Hydrogeological System in Ghana.” Journal of Water Resource and
Protection. 3: 153-163. DOT 10.4236/jwarp.2009.13020.
Balogun, Isaac, Adebayo Olatunbosun, Sojobiand Bosede, and Oyegbemijo Oyedepo.
2016. “Assessment of Rainfall Variability, Rainwater Harvesting Potential and
Storage Requirements in Odeda Local Government Area of Ogun State in
Southwestern Nigeria.” “Journal of Cogent Environmental Science.” 1: 1-37.
DOT http://dx.doi.org/10.1080/23311843.2016.1138597.
Blanchard, Benjamin, and Wolter Fabrycky. 2011. Systems Engineering and Analysis.
Upper Saddle River, NJ: Pearson.
Boensel, Matthew. 2016. Engineering Economies and Cost Estimating SE 3011 Eecture
Slides, Naval Postgraduate School. Monterey, CA.
BRK Brands, Inc. 2005. First Alert: Drinking Water Test Kit. Aurora: First Alert.
Coolahan, James. 2012. An Introduction to the Use of Modeling and Simulation
Throughout the System Engineering Process. Accessed May 6, 2016.
http://www.dtic.mil/ndia/2012systemtutorial/14907.pdf
CraftRO Master 10,000 GPD Brewery Water System. 2016. Accessed November 10,
2016. https://www.uswatersystems.eom/us-water-craftromaster-10-000-gpd-beer-
brewing-system.html
Crowe, Dana, and Alec Feinberg. 2001. Design for Reliability. Boca Raton, FF: CRC
Press.
Department of the Army, Medical Technical Bulletin (TB MED 577). 2010. “Sanitary
Control and Surveillance of Field Water Supplies.” Accessed May 5, 2016.
http ://armypubs .army .mil/med/DR_pubs/dr_a/pdf/tbmed5 77 .pdf
Department of the Navy, Marine Corps Reference Publication (MCRP) 3-02C, “Marine
Combat Water Survival.” Accessed May 5, 2016 http:// www.doctrine.usmc.mil.
95
Emmanuel, Toyobo, and Muili Bamidele. 2013. “Sustainability of Borehole Water
Sehemes through Community Partieipation in Ejigbo, Osun State.” Journal of
Innovative Systems Design and Engineering. 4(9): 79-84.
http://www.iiste.org/Joumals/mdex.php/ISDE/article/view/6259.
ESP Water Products and Benefits. 2016. Accessed September 10, 2016.
https://www.espwaterproducts.eom/purotwist-pt4000-tfc-50-gpd-four-stage-ro-
system/
ESP Water Products. 2016. Understanding Reverse Osmosis (RO): How RO Systems
Work and What they do. Accessed May 8, 2016
https://www.espwaterproducts.com/about-reverse-osmosis/.
Ezeabasili, A.C., O.I. Anike, and A.U. Okonkwo. 2014. “Management of Urban
forDomestic and Industrial Uses and Sustainability in Anambra State, Nigeria.”
International Journal of Water Resources and Environmental Engineering. 6(8):
212-219. DOE 10.5897/IJWREE2013.0441.
EEEXEON Systems Benefit and Highlights. 2014. Accessed May 5 2016.
https ://www.uswatersystems. com/commercial/commercial-systems/reverse-
osmosis/complete-systems.
Eood and Agricultural Organization of the United Nations (EAO). 1999. Eishery Harbor
Manual on the Prevention of Pollution-Bay of Bengal Program. Accessed May 5,
2016. http://www.fao.Org/docrep/x5624e/x5624e00.htm#Contents.
Eubara-Manuel, Isoteim., and Raphael Jumbo. 2014. “The Effect of Septic Tank
Eocations on Borehole Water Quality in Port Harcourt, Nigeria.” International
Journal of Engineering and Technology. 4(5): 236-244.
https://www.researchgate.net/pubhcation/269874652.
Gilli, Eric, Christian Mangan, and Jacques Mundry. 2012. Hydrogeology: Objectives,
Methods, Applications. Boca Raton, EE: CRC Press.
Gillings School of Global Public Health. 2015. “Doctoral Candidate, U.S. Army Works
on Safer Water for Troops.” Accessed Eebmary 25, 2016.
http://global.unc.edu/news/doctoral-candidate-us-army-major-works-on-safer-
water-for-troops/.
Grady, Jeffrey O. 2010. System Synthesis: Product and Process Design. Boca Raton, PE:
CRC Press Taylor & Prancis Group.
Granetto, Paul. 2008. “DOD Inspector General Report: Audit of Potable and Nonpotable
Water in Iraq.” Accessed May 5, 2016
http://www.dodig.mil/audit/reports/ly08/08-060.pdf.
96
Houlihan, Michael, and Patrick Lucia. 1999. “Groundwater Monitoring.” In The
Handbook of Groundwater Engineering, edited by Jacques W. Deheur. Boca
Raton: CRC Press LLC.
Jeje, J.O., and K.T. Oladepo. 2014. “Assessment of Heavy Metals of Borehole and Dug
Wells in Ife North Local Government Area of Osun State, Nigeria.” International
Journal of Science and Technology. 3(4): 209-214. http://www.journalofsciences-
technology .org/archive/2014/april_vol_3_no_4/5268491382172138 .pdf
Kawa, Yahaya, John Kaisam, J. Moiwo and Victoria Kabia. 2016. “Physical, Chemical
and Bacteria Analysis of Drinking Water: Kakua Chiefdom, BO District, Sierra
Leone.” International Journal of Water Resources and Environmental
Engineering. 8(1): 11-23. DOI: 10.5897/IJWREE2015.0610.
Kumar, U.D., J. Crocker, T. Chitra, and H. Saranga. 2006. Reliability and Six Sigma.
New York: NY: Springer.
Lash, Fred. 2011. “Marines Take Steps to Avoid Costly Bottled Water Resupply.”
National Defense, May 4.
http://www.nationaldefensemagazine.org/archive/2011/may/pages/marinestakeste
pstoavoidcostlybottledwaterresupply.aspx.
Maddocks, Andrew, Robert Young, and Paul Reig. 2015. “Ranking the World’s Most
Water-Stressed Countries in 2040.” WRI, August 26.
http://www.wri.org/blog/2015/08/ranking-world%E2%80%99s-most-water-
stressed-countries-2040.
Margasak, Larry. 2008. “Water Reportedly Sickened U.S. Troops in Iraq.” USA Today,
March 9. http://usatoday30.usatoday.eom/news/world/iraq/2008-03-09-
water_N.htm.
Moore, James. 2011. “The U.S. Military’s Reliance on Bottled Water During Military
Operations.” M.S. thesis. National Defense University, Joint Advanced
Warhghting School, Norfolk, VA.
National Aeronautical and Space Administration (NASA). Systems Engineering
Handbook (NASA/SP-2007-6105). 2007. Hanover, MD: NASA.
Norland International Proposal for Vapor Compression Distillation System. 2016.
Accessed September 9, 2016. www.h2olabs.com.
Oyebande, Lekan. 2001. “Water Problems in Africa-How Can the Sciences Help?.”
Hydrological Sciences Journal. 46(6): 947-962. DOI:
0.1080/0262660109492888.
97
Oyebande, Lekan, and Idowu Balogun. 1992. “Water Resources Development in West
Africa beyond the Year 2000; Problems, Needs and Priorities. ” Canadian Journal
of Development Studies. 13: 61-79. D01;l 0.1080/02255189.1992.966942.
Sobsey, Mark. 2002. Managing Water in the Home: Accelerated Health Gains from
Improved Water Supply. Geneva; WHO. Accessed March 14, 2016.
http://www.who.int/water_sanitation_health/dwq/wsh0207/en/.
Stevens, Mark. 2015. Fundamentals of Systems Engineering SE 3100 Lecture Slides,
Naval Postgraduate School. Monterey, CA.
Sugimoto, Alex. 2016. Pugh Matrix. Accessed November 16, 2016. https://alex-
sugimoto.squarespace.com/s/Pugh-Matrix-Template.xls
Systems Engineering Eundamentals. 2001. Department of Defence: Systems Management
College. Eort Belvoir, Virginia: Defence Acquisition University Press.
Systems Engineering Handbook: A Guide for System Life Cycle Process and Activities.
2015. Hoboken, NJ: John Wiley and Sons.
Uneze, Eberechukwu, Ibrahim Tajudeen, and Ola Iwela. 2012. “Cost-Effectiveness and
Benefit-Cost Analyses of Some Water Interventions in Nigeria: The Case of
Bauchi State. ” Journal of Development Effectiveness. 4(4): 497-514. DOE
10.1080/19439342.2012.716075.
Ukpong, E.C., and B.B. Okon. 2013. “Comparative Analysis of Public and Private
Borehole Water Supply Sources in Urban Local Government Area of Akwa Ibom
State, Nigeria.” International Journal of Applied Science and Technology. 3(1):
76-91. http://www.ijastnet.eom/joumals/Vol_3_No_l_January_2013/10.pdf
United Nations Children’s Emergency Eund (UNICEE). 2013. “Children Dying Daily
Because of Unsafe Water Supplies and Poor Sanitation and Hygiene. ” Accessed
Eebmary 25, 2016. http://www.unicef org/media/media_68359.html.
Water Project (TWP). 2016. Installing the Well. Accessed May 8, 2016
https://thewaterproject.org/installing-the-well.
World Bank Group. 2016. Climate Change Knowledge Portal for Development
Practitioners and Policy Makers: Average Monthly Rainfall for Afghanistan from
1990-2012. Accessed May 8, 2016
http://sdwebx.worldbank.org/climateportal/index.cfm?page=country_historical_cl
imate&ThisCCode=APG.
98
World Bank Group. 2016. Climate Change Knowledge Portal for Development
Practitioners and Policy Makers: Average Monthly Rainfall for Nigeria from
1990-2012. Accessed May 8, 2016
http://sdwebx.worldbank.org/elimateportal/index.cfm?page=eountry_historieal_el
imate&ThisRegion=Afriea&ThisCCode=NGA.
World Intelleetual Property Organization (WIPO). 2012. Patent Landscape Report on
Membrane Filtration and UV Water Treatment: A Landscape Report on Selected
Water Treatment Technologies and their Application in Desalination Systems.
Aceessed May 3, 2016.
http://www.wipo.int/edocs/pubdoos/en/patents/947/wipo_pub_947.pdf.
World Health Organization (WHO). 2013a. Technology Notes on Drinking Water,
Sanitation, and Hygiene in Emergencies: Emergency Treatment of Drinking
Water at the Point of Use. Aooessed February 25, 2016.
http://www.unioeforg/oholera/Annexes/Supporting_Resouroes/Annex_9/WHO-
tn5_treatment_water_en.pdf
-. 2013b. Water Quality and Health Strategy 2013-2030. Aooessed February 25,
2016.
http://www.who.int/water_sanitation_health/publioations/2013/water_quality_stra
tegy/en/.
World Resouroe Institute (WRI). 2016. Mapping, Measuring, and Mitigating Global
Water Challenges. Accessed February 25, 2016. http://www.wri.org/our-
work/topios/water.
Yong, Raymond, Catherine Mulligan, and Masaharu Fukue. 2015. Sustainable Practices
in Geoenvironmental Engineering. Booa Raton: CRC Press.
99
THIS PAGE INTENTIONALLY LEET BLANK
100
INITIAL DISTRIBUTION LIST
1. Defense Teehnieal Information Center
Ft. Belvoir, Virginia
2. Dudley Knox Library
Naval Postgraduate Sehool
Monterey, California
101