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MEDRC Series of R & D Reports MEDRC Project: 11-AS-002
Applying Value Engineering Concept in Project
Life Cycle Case Study: Deir El Balah Desalination
Plant
Master of Science Thesis
by
Eng.Samer El Namara
Supervisors Dr. Nabil Sawalhi
Islamic University of Gaza
The Middle East Desalination Research Center
Muscat
Sultanate of Oman
March 2013
MEDRC
ii
The Islamic University Gaza
Higher Education Deanship
Faculty of Engineering
Civil Engineering Department
Engineering projects management
غزة – الجامعة اإلسالمية
العليا الدراسات عمادة
كلية الهندسة
قسم الهندسة المدنية
ادارة المشاريع الهندسية
حياة المشروعتطبيق مفهوم هندسة القيمة على دورة
حالة دراسية : محطة تحلية مياه دير البلح
Applying Value Engineering Concept in Project Life Cycle
Case Study: Deir El Balah Desalination Plant
Submitted by:
Eng.Samer El Namara
Supervised by:
Dr. Nabil Sawalhi
A Thesis Submitted in Partial Fulfillment of Requirements for the Degree of Master of
Science in Engineering Projects Management
م 3131-هـ 3414
iii
بسم هللا الرحمن الرحيم
َوَما َتْوِفيِقي ِإالَّ ِباّللهِ َعَليِْه ))
(( َتَوكَّْلُت َوِإَليِْه ُأِنيبُ
88سورة هود اآلية
iv
Acknowledgement
I would like to express my sincere gratitude to people who assisted me in the realization of
this research:
The Middle East Desalination Research Center (MEDRC), based on Muscat, Sultanate of
Oman for their generous scholarship covering the cost of this research along with the their
continuous cooperation and great support to the researcher in all research stages
Dr. Nabil Sawlhi, Islamic University of Gaza, who is my supervisor for his efforts and
cooperation.
Eng.Rebhy El Sheikh, Deputy Chairman of Palestinian water authority, for his great
support and generous assistance and encouragement
Eng.Omar Shataat, Costal municipalities water utility, for his collaboration and assistance
in providing me with the relevant material.
To the Coastal Municipalities Water Utility staff, for their valuable contribution in the
questionnaire.
The value engineering team, for their support and technical assistant
The professionals I interviewed and those who either responded to the questionnaire or
apologized for other engagements, and finally
I would like also to express my sincere gratitude to the Islamic University of Gaza for its
effort in the facilitation of the graduate studies.
v
Presentation
To my dear mother and to my faithful wife for their honest supplications to Allah to facilitate my mission in performing the enclosed thesis.
Also, to my kids whom motivated me to apply for this master wishing them good health and promising future inshAllah.
Samer El Namara
vi
Abstract
One of the most important challenges that face the people in Gaza Strip is the scarcity of
natural water resources along with continuous growth of consumption level. This situation
lead to a huge deficit in aquifer balance and force the authorities to look for an optimal
alternative source to overcome this difficulty through seawater desalination.
However, the cost of construction of desalination plants have been rapidly increasing in the
last few years, this issue may refer to different reasons related to the project components
and /or other factors affecting the establishment of the plant.
Accordingly, it was very important to find an effective technique to explore this
phenomena and reduce its effect on the cost of water production offered to beneficiaries.
This was clearly presented through the application of value engineering concept.
In order to practically examine the impact of applying this concept through desalination
plants, an intensive survey was conducted to elaborate the most important factors affecting
the establishment of the desalination plant.
Moreover, several interviews were conducted with experts in the field to cross check the
validity of the survey results and figure out other possible considerations
The findings from this investigation was considered in applying the value engineering
concept on a selected case study located in Gaza Strip : Deir El Balah desalination plant in
order to examine the impact of application value Engineering on this project .
Through the value engineering application process, several proposals were discussed and
considered in the study, it was found that the application of the value engineering concept
on the selected case study lead to direct impact in cost saving of approximately 10.33 % for
this project in addition to saving of annual operational cost approximately 330,000USD.
On the light of this result , it was confirmed that applying value engineering is very helpful
tool for such project which will lead to significant saving in cost.
Due to the limited experience in this field in Gaza Strip, its strongly recommended to have
further studies in Gaza strip in this domain to reach to the optimum alternatives in
implementing the value engineering in similar projects
vii
ملخصالمستمر في قطاع غزة هو ندرة الموارد المائية الطبيعية بالتوافق مع النمو المواطنين من أهم التحديات التي تواجه
السلطات الي البحث إلى عجز ضخم في توزان طبقة المياه الجوفية و إجبار أدى االستهالك. هذا الوضعلمستوى ومع ذلك، فإن تكلفة بناء محطات البديل للتغلب على هذه الصعوبة من خالل تحلية مياه البحر. المصدر األمثلعن
األمر يرجع إلى أسباب مختلفة قد تتعلق مكونات ، هذافي السنوات القليلة الماضية تحلية المياه قد ازدادت بشكل مطردالمشروع و/ أو عوامل أخرى مرتبطة بإنشاء المحطة .بالتالي ، كان من المهم جدا العثور على تقنية فعالة الستكشاف
ل تطبيق إنتاج المياه المقدمة للمستفيدين. هذا االمر يمكن تقديمه من خال هذه الظاهرة والحد من تأثيرها على تكلفةومن أجل دراسة تأثير تطبيق هذا المفهوم عمليا من خالل محطات التحلية، تم إجراء دراسة . مفهوم هندسة القيمة
باإلضافة لذلك، تم إجراء عدة مقابالت على إنشاء محطات تحلية المياه. المؤثرة العواملمكثفة لتحديد أهم استقصائية . ممكن توافرها أخرىومعرفة اي اعتبارات نتائج الدراسةتحقق من صحة للمع خبراء في هذا المجال
وهي: محطة تحلية تم استخدام نتائج هذا المسح في تطبيق مفهوم هندسة القيمة على حالة دراسية مختارة في قطاع غزةمة ، يالقمن خالل عملية تطبيق هندسة . بدير البلح من أجل دراسة أثر تطبيق هندسة القيمة على هذا المشروع المياه
قيمة في الحالة الدراسية المختارة الوجد أن تطبيق مفهوم هندسة في الدراسة، الواردةتمت مناقشة العديد من المقترحات في التكلفة التشغيلية توفيرباإلضافة إلى المشروع٪ من قيمة 33.11التكلفة بنحو يؤثر بشكل مباشر على تخفيض
دوالر أمريكي.113،333السنوية قرابة
إلى لما سيؤديهندسة القيمة هو أداة مفيدة جدا لمثل هذا المشروع ه النتيجة، فمن المؤكد أن تطبيق على ضوء هذراء المزيد ونظرا للخبرة محدودة في قطاع غزة في هذا المجال ، فانه يوصى بشدة أن يتم إج توفير كبير في التكاليف.
مفهوم طبيقتفي هذا المجال في قطاع غزة للوصول إلى البدائل المثلى في مشاريع مماثلة من خالل من الدراسات .هندسة القيمة
viii
LIST OF CONTENTS
CHAPTER (1) INTRODUCTION
1.1. BACKGROUND .................................................................................................................................. 2
1.2. RESEARCH PROBLEM .................................................................................................................... 2
1.3. RESEARCH AIM ................................................................................................................................ 3
1.4. RESEARCH OBJECTIVES ............................................................................................................... 3
1.5. JUSTIFICATION ................................................................................................................................ 4
1.6. PRACTICAL SIGNIFICANCE OF THE RESEARCH .................................................................. 4
1.7. HYPOTHESIS ..................................................................................................................................... 5
1.8. CONCEPTUAL FRAME WORK ...................................................................................................... 5
CHAPTER (2) LITERATURE REVIEW
A. PART ONE: VALUE ENGINEERING ..................................................................................................... 7
2.1 INTRODUCTION ............................................................................................................................... 7
2.2 HISTORY OF VALUE ENGINEERING .......................................................................................... 7
2.3 DEFINITION OF VALUE ENGINEERING .................................................................................... 9
2.4 VALUE METHODOLOGY APPLICABILITY ............................................................................. 10
2.5 WHEN VALUE ENGINEERING IS USED .................................................................................... 11
2.6 PROCESS OF VALUE ENGINEERING APPLICATION ........................................................... 12
2.6.1 SAVE INTERNATIONAL APPROACH (1999) ................................................................................... 12 2.6.1.1 PRE-STUDY ................................................................................................................................. 13
2.6.1.2 The Value Study ..................................................................................................................... 15 2.6.1.3 Post Study ............................................................................................................................... 20
2.6.2 VALUE MANAGEMENT ................................................................................................................... 20 2.6.3 ACQUISITION LOGISTICS ENGINEERING. ...................................................................................... 21 2.6.4 CALDWELL ...................................................................................................................................... 22 2.6.5 DELL'ISOLA .................................................................................................................................... 24
B. PART TWO: WATER DESALINATION ............................................................................................... 25
2.7 HISTORY OF DESALINATION ..................................................................................................... 25
2.8 DESALINATION TECHNOLOGIES ............................................................................................. 27
2.8.1 THERMAL TECHNOLOGIES ............................................................................................................ 28 2.8.2 MULTI-STAGE FLASH DISTILLATION (MSF) ................................................................................ 28 2.8.3 MULTI-EFFECT DISTILLATION (MED) ......................................................................................... 29 2.8.4 VAPOR COMPRESSION DISTILLATION ........................................................................................... 30 2.8.5 MEMBRANE TECHNOLOGIES ......................................................................................................... 30
2.8.5.1 Electrodialysis (ED) and Electrodialysis Reversal (EDR) .................................................... 30 2.8.5.2 Reverse Osmosis (RO) and Nanofiltration (NF) .................................................................. 31
2.9 FACTORS AFFECTING COST OF DESALINATION ................................................................ 33
2.9.1 SELECTION OF INTAKE AND CONCENTRATE DISCHARGE............................................................. 33
ix
2.9.2 FEED AND FINISHED WATER QUALITY .......................................................................................... 35 2.9.3 DISTRIBUTION ................................................................................................................................. 36 2.9.4 PERMITTING AND REGULATORY ISSUES........................................................................................ 37 2.9.5 PROJECT DELIVERY MECHANISM ................................................................................................. 37 2.9.6 OTHER ASSOCIATED COSTS ........................................................................................................... 38 2.9.7 OPERATION AND MAINTENANCE COST ......................................................................................... 38 2.9.8 QUALITY OF FEEDING WATER ........................................................................................................ 39 2.9.9 PRETREATMENT ............................................................................................................................. 39 2.9.10 OTHER ELEMENTS AFFECTING THE COST ANALYSIS ................................................................. 39
CHAPTER (3)RESEARCH METHODOLOGY
3.1 INTRODUCTION ............................................................................................................................. 42
3.2 QUANTITATIVE APPROACH ...................................................................................................... 42
3.3 DATA ANALYSIS ............................................................................................................................. 42
3.4 THE POPULATION OF STUDY .................................................................................................... 43
3.5 THE SAMPLE OF THE STUDY ..................................................................................................... 43
3.6 SETTING OF THE STUDY ............................................................................................................. 43
3.7 ELIGIBILITY OF THE STUDY ..................................................................................................... 44
3.7.1 INCLUSION CRITERIA ..................................................................................................................... 44
3.8 QUESTIONNAIRE MAIN CATEGORIES .................................................................................... 44
3.8.1 PART ONE (DEMOGRAPHIC INFORMATION) .................................................................................. 44 3.8.2 PART TWO (THE MOST IMPORTANT FACTORS AFFECTING THE ESTABLISHMENT OF DESALINATION PLANTS).............................................................................................................................. 45 3.8.3 PART THREE (THE PARTIES INVOLVED) ....................................................................................... 45
3.9 STUDY INSTRUMENT (DATA COLLECTION TOOL) ............................................................ 45
3.10 STATISTICAL ASSUMPTIONS AND CRITERIA ...................................................................... 46
3.10.1 QUESTIONNAIRE SCALING ......................................................................................................... 46 3.10.2 RELIABILITY AND VALIDITY OF THE MEASURE ....................................................................... 46 3.10.2.1 VALIDITY OF THE MEASURE ..................................................................................................... 46 3.10.2.2 CONTENT VALIDITY ................................................................................................................... 46 3.10.2.3 STATISTICAL VALIDITY OF THE MEASURE ............................................................................... 47 3.10.2.4 INTERNAL CONSISTENCY ........................................................................................................... 47 3.10.3 RELIABILITY OF THE SCALE ...................................................................................................... 50 3.10.3.1 CRONBACH’S ALPHA .................................................................................................................. 50 3.10.3.2 SPLIT HALF METHOD ................................................................................................................ 50
3.11 STATISTICAL METHODS ............................................................................................................. 51
3.12 QUALITATIVE APPROACH ......................................................................................................... 52
3.12.1 DATA ANALYSIS ......................................................................................................................... 52
3.13 EVALUATION OF THE METHODOLOGY ................................................................................ 52
3.14 DEVELOPING OF THE COMPARISON MODEL ...................................................................... 53
3.15 RESEARCH METHODOLOGY FLOW CHART ......................................................................... 53 CHAPTER (4) SUREVY ANALYSIS AND FINDINGS
4.1 INTRODUCTIONS ........................................................................................................................... 55
4.2 QUESTIONNAIRE ANALYSIS ...................................................................................................... 55
x
4.2.1 PART ONE ....................................................................................................................................... 55 4.2.2 PART TWO ...................................................................................................................................... 59 4.2.3 PART THREE ................................................................................................................................... 63
4.3 STATISTICAL SIGNIFICANCES OF THE QUESTIONNAIRE COMPONENTS .................. 65
4.4 INTERVIEW ..................................................................................................................................... 72
4.4.1 INTERVIEW PROTOCOL .................................................................................................................. 72 4.4.2 INTERVIEW (1) ................................................................................................................................ 73 4.4.3 INTERVIEW (2) ................................................................................................................................ 73 4.4.4 INTERVIEW (3) ................................................................................................................................ 74 4.4.5 CONCLUSION OF INTERVIEWS ........................................................................................................ 74
CHAPTER (5) CASE STUDY
5.1 INTRODUCTION ............................................................................................................................. 76
5.2 PROJECT DATA .............................................................................................................................. 76
5.3 V.E TECHNICAL SUPPORTING TEAM ...................................................................................... 77
5.4 APPLICATION OF VALUE ENGINEERING STUDY ................................................................ 78
5.5 QUALITY MODEL........................................................................................................................... 79
5.6 COST ESTIMATE FOR MASTER FORMAT (BILL OF QUANTITIES ) ................................ 81
5.7 UNIFORMAT PRESENTATION FOR THE BILL OF QUANTITIES ...................................... 82
5.8 APPLICATION OF PARETO LAW ............................................................................................... 82
5.9 WORKSHOP STAGE ....................................................................................................................... 84
5.10 CREATIVITY PHASE ..................................................................................................................... 84
5.11 PRESENTATION OF THE PROPOSALS ..................................................................................... 85
5.11.1 PROPOSAL NO(1) ........................................................................................................................ 85 5.11.2 PROPOSAL NO. (2) ...................................................................................................................... 86 5.11.3 PROPOSAL NO (3) ....................................................................................................................... 89 5.11.4 PROPOSAL NO(4) ........................................................................................................................ 90 5.11.5 PROPOSAL NO (5) ....................................................................................................................... 91
5.12 SUMMARY OF COST SAVING FROM ALL PROPOSAL ........................................................ 92
CHAPTER SIX CONCLUSIONS AND RECOMMENDATIONS
6.1 INTRODUCTION ............................................................................................................................. 94
6.2 CONCLUSIONS ................................................................................................................................ 94
6.3 RECOMMENDATIONS .................................................................................................................. 95
References
ANNEX (1)Questionnaire
ANNEX (2)Standard Bill Of Quantities
ANNEX (3)Uniformat Bill Of Quantities
ANNEX (4)Drawings
xi
LIST OF FIGURES
No. Title
page
1.1: Research Conceptual Frame Work
5
2.1: The Value Engineering Elements
10
2.2: Potential influence of value during project phases
12
2.3: Worth versus Cost Graph
21
2.4: Value Engineering Methodology
24
2.5: VE Methodology
24
2.6: Elements used for cost analysis in RO plants
40
3.1: Methodology Flow Chart
53
4.1: Type of the Company or Organization of the Study Sample
56
4.2: Position in the Company or Organization Of The Study Sample
57
4.3: Experience in the field of water (years) of the study sample
58
4.4: Experience of the Company In The Field Of Water (Years)
58
4.5: Kind of Projects the Organization Is Working On Of the Study Sample
59
4.6: The presented weights and orders for the factors affecting the
establishment of desalination plants
62
4.7: Orders, percentages, for all parties’ participations importance
64
xii
LIST OF TABLES
No. Title
page
2.1: Desalination Technologies and processes
27
2.2: Source Types Range from Beach Wells to Open-Ocean Intakes
34
2.3: Concentrate Disposal Cost
35
2.4: Operation and Maintenance Parameters for Desalination Plant
39
3.1: Questionnaire Scale
46
3.2: Correlation between Items of Factors Affecting The Establishment Of
Desalination Plants & Total Degree Of The Domain
48
3.3: Correlation between Items of Parties Involved & Total Degree of Factor
49
3.4: Cronbach’s alpha values for the Scale and its domain
51
4.1: The Results of Descriptive & Presented Weight for The Factors Affecting
The Establishment of Desalination Plants
60
4.2: The suggested factors affecting the establishment of desalination plants
63
4. 3: One-way ANOVA for differences of factors importance and importance
participation of parties in terms of the type of company
66
4.4: LSD Differences of Importance of Factors In Terms of Company Type
67
4. 5: One-Way ANOVA For Differences Of The Importance Of Factors And
Importance Of Participation Of Parties In Terms Of The Position
67
4.6: One-way ANOVA for differences of factors importance and of
participation of parties in terms of the experience in the field of water
69
4.7: One-way ANOVA for differences of the importance of factors &
importance of parties participation in terms of organization experience in water
70
4.8: One-way ANOVA for differences of importance of factors & importance of
parties’ participation in terms of project type in organization
71
xiii
5.1: V.E Technical Support Team
78
5.2: The Main Quality Model Elements
80
5.3: Summary of Project Bill Of Quantities
81
5.4: Significant Part of the Unifromat Bill of Quantities
82
5.5: Summary of Recommended Proposals for The Bill Of Quantities
85
5.6 : Eliminated Items From Original BoQ Due to Redisgn of RO Unit
87
5.7 : Operation chemicals rates for pre-treatment process
88
5.8 : Yearly Operational Cost Saving from Redsign of RO Unit
89
5.9 : Tentative Power Demand Analysis for the Plant System
91
5.10 : Summary of Cost Saving from All Proposals 92
xiv
1
CHAPTER ONE
2
CHAPTER (1)
INTRODUCTION
1.1. BACKGROUND
Many regions of the world are facing formidable freshwater scarcity. The water resources
are very limited and the consumption rate is hugely increased over the last few years. Gaza
strip in particular suffering from shortage in the aquifer by 55 million cubic meters till
2017. (PWA, 2011)
With the light of the current political and economical circumstances, all relevant bodies
working in water sector agreed on adopting the construction of central desalination plant as
an exclusive solution to get over this problem (PWA, 2011)
However, the cost of construction of desalination plants projects have been rapidly increase
during the different plant life cycle. This may refer to different reasons which depend on
the project itself and /or other related circumstances; accordingly it was very important to
find an effective technique to face these phenomena which may be presented by value
engineering. (Durham, 2001)
1.2. RESEARCH PROBLEM
The value engineering technique is now being applied in most advanced countries in the
world, using these studies effectively by many international companies and institutions that
are specialized in various fields.
The concern of applying the concept of value engineering on the desalination plant project
refer to its clear effect to face the obstructions, whether in terms of technical or financial
issues, and thus the value engineering share significantly on the analysis of these
obstructions and then find the suitable solutions through saving various alternatives, with
keeping functions and features that the owner of product or project looks to achieve, such
as beauty, environment, safety, flexibility and other important factors.(Abdul-Fattaha and
Husseiny, 2001).
http://www.sciencedirect.com/science/article/pii/S0011916400822341#AFF1#AFF1
3
Moreover, it is significantly important to focus on applying this concept in desalination
plant in Gaza strip since Gaza is suffering from serious water consumption problems and in
bad need to establish new desalination plants to come over the huge shortage in water
production. (PWA, 2011)
Therefore, and due to the importance of applying this concept in the construction of
desalination plants in terms of cost reduction, this research will study the impact of
applying value Engineering on selected case study :Deir El Balah desalination plant by
identifying the most effective factors affecting water desalination in the plant in different
stages (planning, design, implantation and operation and maintenance) based on the
available information in this regard.
Obviously as Deir El Balah plant is already existing and operating, the first three stages
will be examined theoretically in comparison model to develop guidelines that may be
considered in establishing the central plant serving Gaza strip
Regarding the fourth stage (operation and maintenance) the research will evaluate the
possibility of any current corrective action that may be taken to expand the capacity of the
existing plant or decreases the unit cost production by applying value engineering in this
stage.
1.3. RESEARCH AIM
Contributing in resolving the water crisis in Gaza strip by considering the value engineering
concept as main factor affecting the cost of potable water production
1.4. RESEARCH OBJECTIVES
1. Identification of factors affecting the water desalination plant
2. Conducting "practical comparison model" for the cost reduction by applying the
value engineering concept on the selected case study (Deir El balah Desalination
plant).
4
1.5. JUSTIFICATION
Scientific significance of the research
There are many advantages related to the application of value engineering in projects, and
the most important of these advantages include:
1. The value engineering is considered from distinctive studies and capable of
providing a number of alternatives through the collective participation in the
brainstorm and evaluation it in order to reach the right decision.
2. Past experiences verified by using value engineering, the efficiency and control in
performance functionality and the projects costs.
3. The value engineering studies contribute in the direct link for the project parties and
approximate the different points of view through collective participation and
creative brainstorm.
4. Value engineering is not limited to one field or a particular area but also beyond to
the possibility of applying it in all areas, whether in the construction section,
agricultural, industrial, or as well as the administrative area.
5. The value studies contribute in the benefit of previous experience of implemented
projects or which have already been studied by avoiding errors which increase the
unjustified cost. (Al-Yousefi, Abdulaziz,2006).
1.6. PRACTICAL SIGNIFICANCE OF THE RESEARCH
The value engineering is new concept in the context of Gaza projects and practically not
applied in most of the implemented or planned projects.
Accordingly the application of this concept on the desalination plant may give guide for
other researcher to extent this application in other projects.
Moreover, the research may represent a valuable practice for the decision makers in the
process of adopting the best alternatives for the central desalination plant serving Gaza strip
in accordance to the master plant.
5
It will be tried to outline all predictable obstacles that may face the implementation of such
project in Gaza strip which will be an early alarm for donors and researcher in this context.
Also the research will be helpful for interested NGOs who are currently implementing
emergency small scale desalination units.
1.7. HYPOTHESIS
The cost of potable water production is lower when value engineering concept is applied in
constructing and operating the desalination plant
1.8. CONCEPTUAL FRAME WORK
Figure 1.1 indicated the main components of the conceptual frame work of the intended
study
Figure 1.1: Research Conceptual Frame Work
•Affects And Guidlines For Central Deslalantion Plant
•Contribution From, Pwa,cmwu And Ingo To Reach Practical Findings
•Access For Adequate Data And Gathering Methodology
•Level Of Knowledge And Interest Of VE Concept For Relevant Parties
PLANNING STAGE
DESIGN STAGE
CONSTRUCTION STAGE
OPERATION AND MAINTANENACE
6
CHAPTER TWO
7
CHAPTER (2)
LITERATURE REVIEW
A. PART ONE: VALUE ENGINEERING
2.1 INTRODUCTION
The methodology of value engineering is now being applied in most of the countries
which is the most advanced in the world, using these studies effectively by many
international companies and institutions that specialize in various fields.
Value engineering, is an analysis of the functions to identify and classify it and then
achieve those required functions by other creative methods that achieve the required
balance between the cost, functionality, performance, appearance and quality by
offering different alternatives, which means making rational changes to the design or
maybe going out with new design achieve the required functions with the highest
quality and lowest cost.
Most studies have indicated that the design phase accounts for 50% of the factors
affecting the cost while the owner only affects the cost by 10%. This is because the
owner is affected by the vision and analysis of others, such as the designer or the
consultant, and sometimes the owner imposes a certain perception which contributes
significantly to unjustified higher costs. Also the owner claims the knowledge and the
experience which makes him to intervene in the design works so he impose specific
ideas which are usually far from reality, such as simulation of designs or similar use of
materials not available or appropriate that fit with the local environment, and all that
under the context that the owner reserves the right to spend the money.(Al-Yousefi,
2006).
2.2 HISTORY OF VALUE ENGINEERING
Larry Miles an Engineer in General Electric Co. of America. Considered as the founder
of the value engineering technique worldwide.
8
In the first years after World War II, Miles was able to overcome at the acute shortage
of basic materials for manufacturing through the use of alternative materials and
designs while maintaining the different functions performed by the products to continue
production and meet commitments.
Miles then worked on the development of this approach between 1947 and 1952 in
order to bring improvement and development in a way of function analysis or
performance and not through the study of materials, parts, and he called it the
"functional analysis" (VA).
This method was a new step to improve and develop the products with reduction in
costs rather than the traditional method to reduce costs which often leads to reduction in
quality or performance level. Then this method moved to government institutions,
specifically the U.S. Navy (Jerjeas and Revay, 1999)
By early of 1961 the actual application was begun for value engineering protocol
through promotion of the various sectors from applying these studies, and followed that
by legislation the necessary laws, and also make training programs and introduction
workshops for value engineering methodology.
With the beginning of 1970, these studies have seen widespread in Japan, Europe,
India, passing to Australia.
As a natural result for these successful experiences and the growing interest in this
profession inside and outside the United States, professional organization has been
established concerning this profession, organized it and enact the necessary laws for
exercise it and exchange experiences.
This organization was called American Society of Value Engineering (SAVE), which
later became an international organization caring with the affairs of the profession
inside and outside the United States (SAVE-International), where the team work
consists of a group of specialists and experts in all fields and being on the top of this
team engineer value supported from the organization "( Al-Yousefi, 2006).
9
2.3 DEFINITION OF VALUE ENGINEERING
There are different names to Value Engineering studies as value analysis , value
engineering and value management , and all these with a single concept attach with the
methodology of the search about solutions and creative practical ideas that contribute in
overcoming many administrative and technical obstruction of the project through
searching for suitable alternatives and solutions working on raising quality and reducing
costs as well as the exceptional performance, taking into account conservation of the
functionality and the time factor.(Al-Yousefi, 2006)
It must be noted that there is a significant difference between the reduction of cost and
Value Engineering.
“Value engineering is not simply about money …it’s about value “(Kirk et al 2002:5)
So it’s according to Hegan (1993) seeking to offer the client acost saving without
determinant to quality or performance .the power of the value engineering rooted in its
objective and disciplined methodology.
The reduction of cost is usually through the elimination of parts of the project and
hashed it to fit the available budget, but the value engineering is as already noted, it
aims to identify items that are not necessary according to functional analysis leading to
the exclusion of unnecessary costs, which usually cause an unjustifiable increase in
costs, accordingly we may hereby mention different definitions concluded in several
value engineering studies:-
"An organized collective effort directed to analyzing the functions of jobs and comply
them with the requirements of the beneficiary then to innovate alternatives to lead those
functions to the lowest or the most appropriate possible cost without compromising
quality and basic functions "( Al-Yousefi, 2006).
"An organized effort directed at analyzing the function of products and services to
achieve the desired functions and the essential characteristics at the best use of costs in
accordance with the wishes and expectations of the user". (SAVE International, 2011).
10
Accordingly, the main elements consisting the value engineering frame work is quality
,function and cost as indicated in Figure 2.1
Figure 2.1: The Value Engineering Elements, (Al-Yousefi, Abdulaziz, 2006)
2.4 VALUE METHODOLOGY APPLICABILITY
The possibility of applying the V.E. concept has wide range in several fields as
illustrated hereunder:
A. The Value Methodology can be applied wherever cost and/or performance
improvement is desired. That improvement can be measured in terms of monetary
aspects and/or other critical factors such as productivity, quality, time, energy,
environmental impact, and durability. VM can beneficially be applied to virtually all
areas of human endeavor
B. The Value Methodology is applicable to hardware, building or other construction
projects, and to “soft” areas such as manufacturing and construction processes, health
care and environment services, programming, management systems and organization
structure. The pre-study efforts for these “soft” types of projects utilizes standard
industrial engineering techniques such as flow charting, yield analysis, and value added
task analysis to gather essential data.
C. For civil, commercial and military engineering works such as buildings, highways,
factory construction, and water/sewage treatment plants, which tend to be one time
Value engineer
Quality
Cost Function
11
applications, VM is applied on a project to project basis. Since these are one-time
capital projects, VM must be applied as early in the design cycle as feasible to achieve
maximum benefits. Changes or redirection of design can be accomplished without
extensive redesign, large implementation cost, and schedule impacts. Typically for
large construction projects, specific value studies are conducted during the schematic
stage and then again at the design development (up to 45%) stage. Additional value
studies may be conducted during the construction or build phase.
D. For large or unique products and systems such as military electronics or specially
designed capital equipment, VM is applied during the design cycle to assure meeting of
goals and objectives. Typically a formalized value study is performed after preliminary
design approval but before release to the build/manufacture cycle. VM may also be
applied during the build/manufacture cycle to assure that the latest materials and
technology are utilized.
E. VM can also be applied during planning stages, and for project/program
management control by developing function models with assigned cost and
performance parameters. If specific functions show trends toward beyond control
limits, value studies are performed to assure the function’s performance remains within
the control limits. (SAVE International, 1999)
2.5 VALUE ENGINEERING APPLICATIONS
VE application is of greatest benefits early in the development of a project with
improvement in value gained. Department of Housing and Works in the Government of
West Australia Value Management Guideline 2005, presented the potential influence of
Value Management according to Figure 2.2.
12
Figure 2.2: Potential influence of value during project phases, (Value Management
guidelines: 2005, West Australia)
2.6 PROCESS OF VALUE ENGINEERING APPLICATION
The process of Value engineering was described by several organization and VE
specialists. By going through these different methodologies we may find that all of
them agreed in the concept and main components of the process application , while
some of them like to merge some stages and others go in further detailed tasks and
activities .
Hereunder will explore the most common approaches in this concern
2.6.1 SAVE International Approach (1999)
The VM Job Plan covers three major periods of activity: Pre-Study, the Value Study,
and Post-Study. All phases and steps are performed sequentially. As a value study
progresses new data and information may cause the study team to return to earlier
phases or steps within a phase on an iterative basis. Conversely, phases or steps within
phases are not skipped.
13
2.6.1.1 Pre-Study
Preparation tasks involve six areas: Collecting/defining User/Customer wants and
needs, gathering a complete data file of the project, determining evaluation factors,
scoping the specific study, building appropriate models and determining the team
composition.
A. Collect User/Customer Attitudes
The User/Customer attitudes are compiled via an in-house focus group and/or
external market surveys. The objectives are to:
1. Determine the prime buying influence;
2. Define and rate the importance of features and characteristics of the product or
project;
3. Determine and rate the seriousness of user-perceived faults and complaints of
the product or project;
4. Compare the product or project with competition or through direct analogy with
similar products or projects.
For first time projects such as a new product or new construction, the analysis may
be tied to project goals and objectives.
The results of this task will be used to establish value mismatches in the
Information Phase.
B. Gather a Complete Data File
There are both Primary and Secondary sources of information. Primary sources are
of two varieties: people and documentation. People sources include marketing (or
the user), original designer, architect, cost or estimating group, maintenance or field
service, the builders (manufacturing, constructors, or systems designers), and
14
consultants. Documentation sources include drawings, project specifications, bid
documents and project plans.
Secondary sources include suppliers of similar products, literature such as
engineering and design standards, regulations, test results, failure reports, and trade
journals. Another major source is like or similar projects. Quantitative data is
desired.
Another secondary source is a site visitation by the value study team. “Site”
includes actual construction location, manufacturing line, or office location for a
new/improved system. If the actual “site” is not available, facilities with
comparable functions and activities may prove to be a valuable source of usable
information.
C. Determine Evaluation Factors
The team, as an important step in the process, determines what will be the criteria
for evaluation of ideas and the relative importance of each criteria to final
recommendations and decisions for change. These criteria and their importance are
discussed with the user/customer and management and concurrence obtained
D. Scope the Study
The team develops the scope statement for the specific study. This statement defines
the limits of the study based on the data-gathering tasks. The limits are the starting
point and the completion point of the study. Just as important, the scope statement
defines what is not included in the study. The scope statement must be verified by
the study sponsor.
E. Build Models
Based on the completion and agreement of the scope statement, the team may
compile models for further understanding of the study. These include such models
as Cost, Time, Energy, Flow Charts, and Distribution, as appropriate for each study.
15
F. Determine Team Composition, Wrap-Up
The Value Study Team Leader confirms the actual study schedule, location and
need for any support personnel. The study team composition is reviewed to assure
all necessary customer, technical, and management areas are represented. The
Team Leader assigns data gathering tasks to team members so all pertinent data will
be available for the study.
2.6.1.2 The Value Study
The value study is where the primary Value Methodology is applied. The effort is
composed of six phases: Information, Function Analysis, Creativity, Evaluation,
Development, and Presentation.
A. Information Phase
The objective of the Information Phase is to complete the value study data package
started in the Pre-Study work. If not done during the Pre-Study activities, the
project sponsor and/or designer brief the value study team, providing an opportunity
for the team to ask questions based on their data research. If a “site” visitation was
not possible during Pre-Study, it should be completed during this phase.
The study team agrees to the most appropriate targets for improvement such as
value, cost, performance, and schedule factors. These are reviewed with
appropriate management, such as the project manager, value study sponsor, and
designer, to obtain concurrence.
Finally, the scope statement is reviewed for any adjustments due to additional
information gathered during the Information Phase.
B. Function Analysis Phase
Function definition and analysis is the heart of Value Methodology. It is the
primary activity that separates Value Methodology from all other “improvement”
16
practices. The objective of this phase is to develop the most beneficial areas for
continuing study. The team performs the following steps:
1. Identify and define both work and sell functions of the product, project, or
process under study using active verbs and measurable nouns. This is often
referred to as Random Function Definition.
2. Classify the functions as basic or secondary,
3. Expand the functions identified in step 1 (optional),
4. Build a function Model - Function Hierarchy/Logic or Function Analysis
System Technique (FAST) diagram.
5. Assign cost and/or other measurement criteria to functions,
6. Establish worth of functions by assigning the previously established
user/customer attitudes to the functions,
7. Compare cost to worth of functions to establish the best opportunities for
improvement,
8. Assess functions for performance/schedule considerations,
9. Select functions for continued analysis,
10. Refine study scope,
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C. Creative Phase
The objective of the Creative Phase (sometimes referred to as Speculation Phase) is
to develop a large quantity of ideas for performing each function selected for study.
This is a creative type of effort, totally unconstrained by habit, tradition, negative
attitudes, assumed restrictions, and specific criteria. No judgment or discussion
occurs during this activity. The quality of each idea will be developed in the next
phase, from the quantity generated in this phase.
There are two keys to successful speculation: first, the purpose of this phase is not
to conceive of ways to design a product or service, but to develop ways to perform
the functions selected for study. Secondly, creativity is a mental process in which
past experience is combined and recombined to form new combinations. The
purpose is to create new combinations which will perform the desired function at
less total cost and improved performance than was previously attainable.
There are numerous well accepted idea generation techniques. The guiding
principle in all of them is that judgment/evaluation is suspended. Free flow of
thoughts and ideas - without criticism - is required.
D. Evaluation Phase
The objectives of the Evaluation Phase are to synthesize ideas and concepts
generated in the Creative Phase and to select feasible ideas for development into
specific value improvement.
Using the evaluation criteria established during the Pre-Study effort, ideas are
sorted and rated as to how well they meet those criteria. The process typically
involves several steps:
1. Eliminate nonsense or “thought-provoker” ideas,
2. Group similar ideas by category within long term and short term implications.
Examples of groupings are electrical, mechanical, structural, materials, special
processes, etc,
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3. Have one team member agree to “champion” each idea during further
discussions and evaluations. If no team member so volunteers, the idea or
concept is dropped,
4. List the advantages and disadvantages of each idea,
5. Rank the ideas within each category according to the prioritized evaluation
criteria using such techniques as indexing, numerical evaluation, and team
consensus,
6. If competing combinations still exist, use matrix analysis to rank mutually
exclusive ideas satisfying the same function,
7. Select ideas for development of value improvement,
If none of the final combinations appear to satisfactorily meet the criteria, the value
study team returns to the Creative Phase.
E. Development Phase
The objective of the Development Phase is to select and prepare the “best”
alternative(s) for improving value. The data package prepared by the champion of
each of the alternatives should provide as much technical, cost, and schedule
information as practical so the designer and project sponsor(s) may make an initial
assessment concerning their feasibility for implementation. The following steps are
included:
1. Beginning with the highest ranked value alternatives, develop a benefit analysis
and implementation requirements, including estimated initial costs, life cycle
costs, and implementation costs taking into account risk and uncertainty,
2. Conduct performance benefit analysis,
3. Compile technical data package for each proposed alternative,
a. written descriptions of original design and proposed alternative(s),
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b. sketches of original design and proposed alternative(s),
c. cost and performance data, clearly showing the differences between the
original design and proposed alternative(s),
d. any technical back-up data such as information sources, calculations, and
literature,
e. schedule impact,
4. Prepare an implementation Plan, including proposed schedule of all
implementation activities, team assignments and management requirements.
5. Complete recommendations including any unique conditions to the project
under study such as emerging technology, political concerns, impact on other
ongoing projects, marketing plans, etc.
F. Presentation Phase
The objective of the Presentation Phase is to obtain concurrence and a commitment
from the designer, project sponsor, and other management to proceed with
implementation of the recommendations. This involves an initial oral presentation
followed by a complete written report.
As the last task within a value study, the VM study team presents its
recommendations to the decision making body. Through the presentation and its
interactive discussions, the team obtains either approval to proceed with
implementation, or direction for additional information needed.
The written report documents the alternatives proposed with supporting data, and
confirms the implementation plan accepted by management. Specific organization
of the report is unique to each study and organization requirements.
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2.6.1.3 Post Study
The objective during Post-Study activities is to assure the implementation of the
approved value study change recommendations. Assignments are made either to
individuals within the VM study team, or by management to other individuals, to
complete the tasks associated with the approved implementation plan.
While the VM Team Leader may track the progress of implementation, in all cases the
design professional is responsible for the implementation. Each alternative must be
independently designed and confirmed, including contractual changes if required,
before its implementation into the product, project, process or procedure. Further, it is
recommended that appropriate financial departments (accounting, auditing, etc.)
conduct a post audit to verify to management the full benefits resulting from the value
methodology study. Further, it is recommended that appropriate financial departments
(accounting, auditing, etc.) conduct a post audit to verify to management the full
benefits resulting from the value methodology study.
2.6.2 Value Management
The Department of Housing and Works in Western Australia developed value
management guidelines. It almost has the same steps for VE methodology as SAVE Int.
methodology.
The steps of Value Management process are:
1. Information Phase: essentially preparatory work for the study, including items
such as the development of objectives, key issues and concerns, background
information, key assumptions, cost overview and study scope.
2. Analysis Phase: includes functional analysis, establishing system links, testing
parameters and rationalizing data.
3. Creative Phase: is predominantly concerned with encouraging divergent ideas,
lateral thinking and brainstorming, and generating alternatives for better value
alternatives.
4. Evaluation Phase: ideas are assessed, culled and prioritized to identify viable
alternatives.
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5. Development and Reporting Phase: options and rationale are refined and
documented into action plans for recommendation to the project decision maker.
2.6.3 Acquisition Logistics Engineering.
Acquisition Logistics Engineering (ALE) presented the Value Engineering six
phase’s job Plan as The Department of Housing and Works in Western Australia did
with addition of Implementation Phase and with some differences. ALE
methodology steps are:
1. Information Phase: in addition to gathering information, ALE added that VE
team establishes the areas that will allow for the most improvement and isolates
the major cost items.
2. Function Analysis Phase: sometimes it is performed within information phase.
FAST model is developed as well as cost and cost worth models. An initial
assessment is done to find mismatch between cost and value. This can be shown
graphically by plotting each item's worth versus cost percentage as shown in
Figure below where the numbers in the circles represents the value index of
functions. (El Sadawi, 2008)
Figure 2.3:Worth Versus Cost Graph, (El Sadawi, 2008)
22
3. Creative Phase: in this phase, team brainstorming identifies many alternative
ways of performing the functions of the candidate items having the greatest
worth/cost mismatch.
4. Evaluation Phase: a first cut through alternatives should eliminate impractical or
unfeasible alternatives. Advantages and disadvantages of each alternative in
addition to cost are concluded. If every alternative is eliminated during this
phase, the team must return to the creative phase.
5. Development Phase: the remaining alternatives are refined and developed into a
value engineering proposals including detailed description of the alternatives
including benefits in terms of cost and performance.
6. Implementation Phase: it is sometimes broken into two parts, one for
presentation, and approval and the other for formal implementation.
2.6.4 Caldwell
Caldwell (2006) methodology is composed of the following phases:
1. Information Phase: presentation is made to the VE team to explain the main
concepts of the design. This includes project objectives, design constrains,
drawings, specifications, the special conditions and the estimated cost. Caldwell
prefers that those who present the information should not be part of the VE team.
2. Function Analysis: in this phase major project components are identified as well
as their functions and estimated cost.
3. Speculation: during the speculation phase, the VE team considers each design
component and suggests alternative means of accomplishing the function of the
component. Brainstorming is the most suitable technique.
4. Alternative Comparison: this phase is done to define comparison criteria so that
alternatives can be compared. This phase is preferred to be performed using
brainstorming initially and then through a detailed definitions of each criteria
Weights of criteria are developed by VE Team.
5. Analysis: analyzing alternatives involves comparing them to the criteria. Each
team participant numerically evaluates each alternative against a specific
23
criterion. Scores may vary from 1 to 5 with 1 identified as poor and 5 is very
good.
6. Concept Development: during the concept development phase, the concept
selected by the VE team is organized and refined before presentation to the
owner. Sketches may be prepared or a narrative report compiled. Cost estimates
may be refined.
7. Presentation and Implementation: in the presentation/implementation phase, VE
recommendations are presented to the client, owner, or project manager who is
sponsoring the project. The project manager decides whether the VE
recommendations should be incorporated into remedial action.
8. Report: depending on the budget, topic, and significance of the VE workshop, a
formal report may be prepared. Generally the most cost-effective method is to
have the flipcharts photo-reproduced, copied, collated, and distributed. This
provides a full record of deliberations, scores, recommendations, etc.
Caldwell elaborates the criteria for both the facilitator of the job plan and the
participants as follows:
a. The Facilitator
The facilitator should be chosen with care. He is not required to have specific
knowledge of the project or even of the technologies involved. His role is simply to
act as a neutral presence and to make certain that the workshop is conducted in
accordance with standard VE procedures.
b. Participants
The number of participants is between five and twelve. Never let the number of
participants rise above twelve. There should be a balance of senior and mid-level
experience. The majority should be well versed in the technology being examined.
Caldwell presents VE methodology in Figure 2.4
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Figure 2.4:ValueEngineering Methodology, (Caldwell,2006)
2.6.5 Dell'Isola
Dell’Isola method is described simply in Figure 2.5, which presents a schematic
flow chart for the methodology of applying VE concept
Figure 2.5: VE Methodology, (Dell'Isola, 1998)
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B. PART TWO: WATER DESALINATION
As the research will extrapolate the impact of applying value engineering in existing
desalination plant in Gaza, it will be essential to provide an intensive overview on
desalination literature related to the application of value engineering.
Therefore, the presented literature hereunder will focus mainly on the importance
factors affecting the quality, cost and function in desalination plants.
2.7 HISTORY OF DESALINATION
Obviously Desalination can be considered as a natural phenomenon through natural
distillation cycle of water evaporating from the sea and then condensing to form Pure
rain water, also there is other kind of natural occurrences leaded to desalination such as
freezing of seawater near the polar region. Where The ice crystals formed are pure
water, the salt being excluded from participation in the crystal growth.
However, since the turn of the century, necessity has driven scientists and engineers to
utilize desalination technology of varying effectiveness to produce pure water from
saline water. (Al-Shayji, 1998)
With the development of temperature and pressure measurements, together with an
understanding of the properties of gases, land desalination began to play an important
role.
The first commercial land-based seawater desalination plant was installed by the
Ottomans in Jeddah, Saudi Arabia. This crude distillation unit was a boiler working
under atmospheric pressure, but this unit suffered from severe scale deposits and
corrosion problems. It is now part of a historical monument on Jeddah Corniche.
With the improvement in submerged-tube technology, the first evaporators with a total
capacity in excess of 45,000 m3/d were built in Kuwait Curacao in the early 1950’s.
But it was not until the development of the multistage flash distillation method by
Professor Robert Silver in the 1950’s, when the research and development of saline
water conversion was promoted, that desalination became a practical solution to the
shortage of drinking water.
The historical turning point in the history of desalination is the introduction of multi
stage flash desalination (MSF) in Kuwait in 1957. The Kuwait Department of
26
Electricity and Water placed an order with Westinghouse for four 0.5-million-gallon-
per-day (MGD),evaporator units each with four stages, designed by Rowland Colte.
Their success encouraged the authority in Kuwait to go for larger and more efficient
desalination units, and to accept an offer from G and J Weir to supply a new
desalination concept known as the “Multistage Flash”.
The innovator of the multistage flash system was Professor Robert Silver. Although he
held patents on the process both in Europe and the USA, he never received any
financial rewarded for his work.
With this success, companies all over the world, especially in the USA and the UK,
undertake extensive research and development on large flash-type evaporator units to
achieve lower production cost.
The installation of similar evaporators manufactured by other contractors followed the
great success of flash evaporation. Subsequently, Sasakura installed the first 5 million
gallon-per-day MSF units at Shuwaikh in Kuwait. Similar units were then installed in
the new Kuwait plants located at Shuiabah. The success of these large units, proving
that the MSF process could produce water economically and with greater reliability
than previous systems, set the stage for the great advances in desalination capacity that
were to follow in the 1970-1980’s (Temperly, 1995).
In 1953, Reid, C. E. and Breton, E. J. at the University of Florida proposed a research
program to the Office of Saline Water (OSW). They developed a membrane that was
made of a cellular acetate material and had the ability to reject salt. However, the water
flux through the dense membrane was too low to have commercial significance.
The major breakthrough in membrane development came in a parallel research
program,
from 1958 to 1960, at the University of California at Los Angeles (UCLA) where
S.Leob, and S. Sourirajan were credited with making the first high-performance
membranes by creating an asymmetric cellulose acetate structure with improved salt
rejection and water flux.
In 1965, the UCLA team installed the first municipal reverse osmosis plant in Coalinga,
California. The plant was desalting water containing 2,500 ppm salts, and
producing5,000 GPD with a tubular cellular acetate membrane. The development of the
27
tubular, spiral-wound, and hollow-fine-fiber modules together with the development of
the polyamide membranes takes place from 1965-1970.
Through the 1980s, improvements were made to these membranes to increase water
flux and salt rejection with both brackish water and seawater. Brackish water is water
that contains dissolved matter at an approximate concentration range from 1,000-35,000
mg/l. (Al-Shayji,1998)
2.8 DESALINATION TECHNOLOGIES
A desalination process essentially separates saline water into two parts - one that has a
low concentration of salt (treated water or product water), and the other with a much
higher concentration than the original feed water, usually referred to as brine
concentrate or simply as ‘concentrate’.
The two major types of technologies that are used around the world for desalination can
be broadly classified as either thermal or membrane. Both technologies need energy to
operate and produce fresh water. Within those two broad types, there are sub-categories
(processes) using different techniques. The major desalination processes are identified
in Table 2.1.
Table 2.1: Desalination Technologies and Processes
Thermal and membrane capacity on a worldwide basis was about 7 billion gallons per
day (bgd) in early 2000, with about 50% in thermal processes and 50% in membrane
technologies. This is total installed capacity since the early 1950s, and not all of that
capacity may be in operation. On a global basis, desalination capacity increased at
almost 12 percent per year, from 1972 through 1999. There have been over 8,600
desalination plants installed worldwide, with approximately 20 percent of them in the
Thermal Technology Membrane Technology
Multi-Stage Flash Distillation (MSF) Electrodialysis (ED)
Multi-Effect Distillation (MED) Electrodialysis reversal (EDR)
Vapor Compression Distillation (VCD) Reverse Osmosis (RO)
28
U.S., the largest number of any country in the world. In terms of capacity however, the
U.S. ranks second globally (U.S Ministry of Interior, 2003).
2.8.1 Thermal Technologies
Thermal technologies, as the name implies, involve the heating of saline water and
collecting the condensed vapor (distillate) to produce pure water. Thermal technologies
have rarely been used for brackish water desalination, because of the high costs
involved. They have however been used for seawater desalination and can be sub-
divided into three groups: Multi-Stage Flash Distillation (MSF), Multi-Effect
Distillation (MED), and Vapor Compression Distillation (VCD).
2.8.2 Multi-Stage Flash Distillation (MSF)
This process involves the use of distillation through several (multi-stage) chambers. In
the MSF process, each successive stage of the plant operates at progressively lower
pressures. The feed water is first heated under high pressure, and is led into the first
‘flash chamber’, where the pressure is released, causing the water to boil rapidly
resulting in sudden evaporation or ‘flashing’. This ‘flashing’ of a portion of the feed
continues in each successive stage, because the pressure at each stage is lower than in
the previous stage. The vapor generated by the flashing is converted into fresh water by
being condensed on heat exchanger tubing that run through each stage. The tubes are
cooled by the incoming cooler feed water. Generally, only a small percentage of the
feed water is converted into vapor and condensed.
Multi-stage flash distillation plants have been built since the late 1950s. Some MSF
plants can contain from 15 to 25 stages, but are usually no larger than 15 mgd in
capacity. MSF distillation plants can have either a ‘once-through’ or ‘recycled’ process.
In the ‘once-through’ design, the feed water is passed through the heater and flash
chambers just once and disposed of, while in the recycled design, the feed water for
cooling is recycled. Each of these processes can be structured as a ‘long tube’ or ‘cross
tube’ design. In the long tube design (built at Freeport in 1961), tubing is parallel to the
concentrate flow, while in the cross tube design, tubing is perpendicular to the
concentrate flow.
29
MSF plants are subject to corrosion unless stainless steel is used extensively. In
addition to corrosion, MSF plants are also subject to erosion and impingement attack
(U.S. Bureau of Reclamation, 2003). Erosion is caused by the turbulence of the feed
water in the flash chamber, when the feed water passes from one stage to another.
Distillation processes produce about 3.4 billion gpd globally, which is about 50 percent
of the worldwide desalination capacity. MSF plants provide about 84 percent of that
capacity. Most of those plants have been built overseas, primarily in the Middle East,
where energy resources have been plentiful and inexpensive.
2.8.3 Multi-Effect Distillation (MED)
The MED process has been used since the late 1950s and early 1960s. Multi-effect
distillation occurs in a series of vessels (effects) and uses the principles of evaporation
and condensation at reduced ambient pressure. In MED, a series of evaporator effects
produce water at progressively lower pressures. Water boils at lower temperatures as
pressure decreases, so the water vapor of the first vessel or effect serves as the heating
medium for the second, and so on. The more vessels or effects there are, the higher the
performance ratio. Depending upon the arrangement of the heat exchanger tubing,
MED units could be classified as horizontal tube, vertical tube or vertically stacked tube
bundles
There have been several MED plants built in the U.S. and overseas. Three low-
temperature MED plants with a combined capacity of 3.5 mgd have been operating
successfully in St. Thomas, U.S. Virgin Islands, where desalinated water is the principal
water supply source (Krishna, 1989). The MED units are operated by the Virgin Islands
Water and Power Authority. Steam from the power plant is directed to the evaporators
in the desalination units. Product water is obtained as condensate of the vapor from
each vessel. Several MED plants are found overseas, both in the Caribbean and in the
Middle East.
30
2.8.4 Vapor Compression Distillation
The vapor compression distillation (VCD) process is used either in combination with
other processes such as the MED, or by itself. The heat for evaporating the water comes
from the compression of vapor, rather than the direct exchange of heat from steam
produced in a boiler (Buros, 2000). Vapor compression (VC) units have been built in a
variety of configurations. Usually, a mechanical compressor is used to generate the heat
for evaporation. The VC units are generally small in capacity, and are often used at
hotels, resorts and in industrial applications.
2.8.5 Membrane Technologies
Membrane technologies can be subdivided into two broad categories: Electro
dialyis/Electro dialysis Reversal (ED/EDR), and Reverse Osmosis (RO).
2.8.5.1 Electro dialysis (ED) and Electro dialysis Reversal (EDR)
Electro dialysis (ED) is a voltage-driven membrane process. An electrical potential is
used to move salts through a membrane, leaving fresh water behind as product water.
ED was commercially introduced in the 1960s, about 10 years before reverse osmosis
(RO), Although ED was originally conceived as a seawater desalination process, it has
generally been used for brackish water desalination.
ED depends on the following general principles:
- Most salts dissolved in water are ions, either positively charged (cations), or
negatively charged (anions).
- Since like poles repel each other and unlike poles attract, the ions migrate toward the
electrodes with an opposite electric charge
- Suitable membranes can be constructed to permit selective passage of either anions or
cations.
In a saline solution, dissolved ions such as sodium (+) and chloride (-) migrate to the
opposite electrodes passing through selected membranes that either allow cations or
anions to pass through (not both). Membranes are usually arranged in an alternate
pattern, with anion-selective membrane followed by a cation-selective membrane.
During this process, the salt content of the water channel is diluted, while concentrated
31
solutions are formed at the electrodes. Concentrated and diluted solutions are created in
the spaces between the alternating membranes, and these spaces bound by two
membranes are called cells. ED units consist of several hundred cells bound together
with electrodes, and is referred to as a stack. Feed water passes through all the cells
simultaneously to provide a continuous flow of desalinated water and a steady stream of
concentrate (brine) from the stack.
In the early 1970s, the Electro dialysis Reversal (EDR) process was introduced (Buros,
2000). An EDR unit operates on the same general principle as an ED unit, except that
both the product and concentrate channels are identical in construction. At intervals of
several times an hour, the polarity of the electrodes is reversed, causing ions to be
attracted in the opposite direction across the membranes. Immediately following
reversal, the product water is removed until the lines are flushed out and desired water
quality restored. The flush takes just a few minutes before resuming water production.
The reversal process is useful in breaking up and flushing out scales, slimes, and other
deposits in the cells before they build up. Flushing helps in reducing the problem of
membrane fouling.
Because of the inherent characteristics of the electrical process used in ED units, they
are normally used to desalinate brackish water, rather than high salinity water such as
seawater. The few ED units that are located in Texas are those that are used in low-
salinity applications such as surface water desalination (Lake Granbury and Sherman,
2001).
2.8.5.2 Reverse Osmosis (RO) and Nano filtration (NF)
In relation to thermal processes, Reverse Osmosis (RO) is a relatively new process that
was commercialized in the 1970s (Buros, 2000). Currently, RO is the most widely used
method for desalination in the United States. The RO process uses pressure as the
driving force to push saline water through a semi-permeable membrane into a product
water stream and a concentrated brine stream. Nano filtration (NF) is also a membrane
process that is used for removal of divalent salt ions such as Calcium, Magnesium, and
Sulphate. RO, on the other hand, is used for removal of Sodium and Chloride. RO
processes are used for desalinating brackish water (TDS>1,500 mg/l), and seawater.
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Osmosis is a natural phenomenon by which water from a low salt concentration passes
into a more concentrated solution through a semi-permeable membrane. When pressure
is applied to the solution with the higher salt concentration solution, the water will flow
in a reverse direction through the semi-permeable membrane, leaving the salt behind.
This is known as the Reverse Osmosis process or RO process.
An RO desalination plant essentially consists of four major systems:
a) Pretreatment system,
b) High-pressure pumps,
c) Membrane systems,
d) Post-treatment.
Pre-treatment is very important in RO because the membrane surfaces must remain
clean. Therefore, all suspended solids must be first removed, and the water pre-treated
so that salt precipitation or microbial growth does not occur on the membranes. Pre-
treatment may involve conventional methods such as a chemical feed followed by
coagulation/flocculation/sedimentation, and sand filtration, or pre-treatment may
involve membrane processes such as microfiltration (MF) and ultrafiltration (UF). The
choice of a particular pre-treatment process is based on a number of factors such as feed
water quality characteristics, space availability, RO membrane requirements, etc.
High pressure pumps supply the pressure needed to enable the water to pass through the
membrane and have the salt rejected. The pressures range from about 150 psi for
slightly brackish water to 800 - 1,000 psi for seawater.
The membrane assembly consists of a pressure vessel and a semi-permeable membrane
inside that permits the feed water to pass through it. RO membranes for desalination
generally come in two types: Spiral wound and Hollow fiber. Spiral wound elements
are actually constructed from flat sheet membranes. Membrane materials may be made
of cellulose acetate or of other composite polymers. In the spiral wound design, the
membrane envelope is wrapped around a central collecting tube. The feed water under
pressure, flows in a spiral path within the membrane envelope, and pure (desalinated)
water is collected in the central tube. As a portion of the water passes through the
membrane, the remaining feed water increases in salt content. A portion of the feed
water is discharged without passing through the membrane. Without this discharge, the
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pressurized feed water would continue to increase in salinity content, causing super-
saturation of salts. The amount of feed water that is discharged as concentrate ranges
from about 20 percent for brackish water to about 50 percent for seawater (Krishna,
1989).
2.9 FACTORS AFFECTING COST OF DESALINATION
Cost is sensitive issue which affects the decision makers preferable and selections;
however each technology may have its own characteristics in terms of resources, design
aspects and other direct and indirect cost parameters.
As the adopted technology in intended case study and the planned central desalination
plant in Gaza strip is the sea water reverse osmosis, we will highlight herewith the most
effective factors affecting the cost terminology (Water reuse Association Desalination
Committee, 2012)
2.9.1 Selection of Intake and Concentrate Discharge
Feed water intake configuration directly affects capital and operational costs of the
treatment process. Without consideration for the cost of land associated with each
option, beach well intakes are usually less costly on an equipment basis. However, once
land acquisition and easements are factored into the process, this intake type is typically
40 to 50%more costly than an open intake of similar capacity. Horizontal and slant
wells are comparable to open intake (yet more costly than co-located open intakes using
existing infrastructure), and infiltration galleries typically cost more than open intakes.
Of all the intake options, only open intakes have the longest-running installation history
and reliability necessary to support the full-scale development of a large desalination
facility at a new site. As a result, there is a significant depth of understanding related to
the costs associated with constructing open intakes as well as the associated discharge
pipeline.
Few SWRO facilities exist employing an intake type differing from the conventional
open-intake. This lack of available installations for use as a qualitative benchmark for
costing same-site alternatives is important for planners and engineers focused on
process considerations and/or cost comparisons. However, published information is
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limited and can be site-specific. Generalized guidance is contained in Table 2.2: Source
types range from beach wells to open-ocean intakes (Water Reuse Association, 2012)
Table 2.2: Source Types Range from Beach Wells to Open-Ocean Intakes
Various methods are available to dispose of the concentrate stream, and the availability
of alternatives will vary due to many site-specific variables. With that consideration,
conveyance alternatives and a range of costs associated with each alternative are
contained in Table 2.3 The costs do not include conveyance attributable to connecting
the desalination plant to the disposal location (in the case of discharge to the ocean, this
would be from the desalination plant to the shore line) because the conveyance distance,
terrain, and associated costs are site-specific and highly variable, and this conveyance
cost can dominate disposal costs.
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Table 2.3: Concentrate Disposal Cost
By comparison, most of the desalination plants yielding the lowest water production
costs have concentrate discharges either located in coastal areas with very intensive
natural mixing or are combined with power plant outfall structures which use the
buoyancy of the warm power plant cooling water to provide accelerated initial mixing
and salinity plume dissipation at lower cost. The intake and discharge facility costs for
these plants are usually less than 10% of the total desalination plant costs.
2.9.2 Feed and Finished Water Quality
The type of pretreatment system and type of pretreatment technology selected are very
dependent on the feed water quality. Because open ocean feed water (compared with
well water, for example) will typically contain a greater level of suspended material and
impurities that could possibly foul a reverse osmosis membrane, the capability of the
pretreatment necessary to suitably pre-condition the feed water is crucial to ensure a
long, sustainable membrane service life. For example, some coastal well water supplies
and certain open ocean sources are generally expected to contain very low levels of
foulants and particulates; therefore, a lesser-degree of pretreatment may be warranted. It
is important to keep this