1. ENG421 (5ab) – Water Treatment Plant Costs
What is cost estimating?
Cost Estimating Strategy
Water Treatment Processes
Typical Costs
Cost Estimating Methodology

2. What is cost estimating? (1 of 4)
Cost Estimation
arriving at a numerical value for the likely costs of a project, product or service
accuracy depends on process used, data used, intended purpose, experience of people preparing the estimate

3. What is cost estimating? (2 of 4)
Classification of Cost Estimates (Week 7 – ENG302)

4. What is cost estimating? (3 of 4)
Rules of Thumb
- experience improves accuracy of estimate
- estimates are not precise
may be ± $1,000, or ± $10,000, or ± $1,000,000
- the more that is known about the design, the better the
estimate will be
e.g. volumes, flow rates, redundancies in equipment
- review the estimate (by someone with appropriate experience)
- check your calculations

5. What is cost estimating? (4 of 4)
Historical Data
- based on experience
- will vary depending on where, when
- give an indication (only)
- nonetheless, very useful
- serve as basis for cost calculations

6. Approach to Cost Estimation of a Plant Design
Establish level of design/cost estimate required
order of magnitude
factored estimate
controlled estimate
detailed or definitive
Follow the 10 basic rules/guidelines of plant design
Apply cost estimating strategy
Check numbers before releasing
e.g. compare with similar plants, ask experienced engineers

7. Plant Design Philosophy (1 of 3)
10 basic rules/guidelines
Analyse and evaluate raw water quality and required water quality
Evaluate local conditions
The treatment system should be :
simple
reliable
effective
proven treatment processes (usually)
Treatment system shall be reasonably conservative and cost effective

8. Plant Design Philosophy (2 of 3)
10 basic rules/guidelines (cont)
Apply best knowledge and skill available to the design
Treatment system should be easy to build within a reasonable period of time
Treatment system should be easy to operate
maximum operational flexibility
minimum operating and maintenance costs

9. Plant Design Philosophy (3 of 3)
10 basic rules/guidelines (cont)
Treatment plant should be aesthetically pleasing
minimum environmental impacts
Design engineers to work in their area of expertise
ethical behaviour
(ENG101 Week 7 : “Members shall act only in
areas of their competence and in a careful
and diligent manner”)
Respect wishes of the owner (knowledge and experience) and include if within established budget

10. Cost Estimating Strategy (1 of 5)
Four basic components
Site conditions
Classification of work and quantity take-offs
Construction program
Unit cost development

11. Cost Estimating Strategy (2 of 5)
Site conditions
Project cost effected directly by :
topography
geology
cultural
climate
socio-economics
Design and construction costs effected directly by :
nature of soil (physical characteristics of soil)
underground water table
local construction costs
source of imported materials
availability of disposal sites for excavated soil
Also consider impact on costs of :
access to site
working conditions
productivity of local labour
Foreign country issues :
taxes
import duties
port and freight charges
currency exchange rates
specific laws and regulations

12. Cost Estimating Strategy (3 of 5)
Classification of work and quantity take-offs
When design and specification are complete :
Divide project into specific bid items
Break down items into individual categories of work
Separate cost estimate for each item
Quantities (numerical figures) tabulated
make sure units (e.g. metres, days, hours) are correct
Project costs may be reduced by lump sum approach

13. Cost Estimating Strategy (4 of 5)
Construction program
Construction program based on classification of work and quantity take-offs
detailed measurement of materials and labour required to finish construction
Specific items include :
number of labourers, skilled workers and professionals
types and numbers of construction equipment
frequency and duration of use of construction equipment
Construction progress schedule
e.g. Gantt chart
sequential and concurrent operations
critical path
Mobilisation/preparation at beginning of project
Demobilisation/completion of work

14. Cost Estimating Strategy (5 of 5)
Unit cost development
Determine unit costs for :
- direct labour
establish schedule
divide project into various labour categories
e.g. labour, skilled, professional
use hourly rates (plus oncosts) for categories
- direct equipment operating costs
fuel, oil, tyres, spare parts
labour – operator, maintenance/repairs
- consumable materials
items used during construction, not permanent
e.g. small tools, gloves, overalls, welding rods
- non-consumable materials
materials and equipment installed on a permanent basis

15. Costs – Direct, Indirect
Direct Costs
- direct labour
- operation of construction equipment
- consumable and non-consumable materials
- subcontracted services
Indirect Costs
- administrative and overhead labour
- transportation and equipment overhead
- general office expenses
- staff expenses
- on-site project office
- drawing office activities
- etc

16. Conventional and Advanced Water Treatment Processes
selection depends on raw water quality and required water quality
Conventional Water Treatment
Two Stage Filtration
Direct Filtration
Conventional Treatment
Advanced Water Treatment
best quality drinking water is beyond safe drinking water
remove
Total Organic Carbon (TOC)
Disinfection Byproducts (DBPs)
micro-organisms, e.g. Cryptosporidium oocysts
turbidity
Maximum Contaminant Levels (MCLs)
Ozonation
Granular Activated Carbon adsorption (GAC
Biological Aerated Filter (BAF)
high rate Dissolved Air Flotation (DAF)
membrane filtration
UV disinfection

17. Conventional Water Treatment Processes (1 of 3)

18. Conventional Water Treatment Processes (2 of 3)

19. Conventional Water Treatment Processes (3 of 3)

20. Advanced Water Treatment Processes (1 of 6)

21. Advanced Water Treatment Processes (2 of 6)

22. Advanced Water Treatment Processes (3 of 6)

23. Advanced Water Treatment Processes (4 of 6)

24. Advanced Water Treatment Processes (5 of 6)

25. Advanced Water Treatment Processes (6 of 6)

26. Typical Construction Costs – Water Treatment Plant

27. Detailed Cost Estimate – Water Treatment Plant

28. Cost Estimating Methodology (1 of 7)
Cost estimation considerations
Cost estimation is integral part of design process
Design process will be re-iterative
order of magnitude → factored estimate → controlled estimate → detailed or definitive
design and costs become increasingly accurate
Check costs against capital budget
Early on, multiple alternative processes considered
costs may help in selection process (compare processes)
Keep design team and stakeholders informed
Know the difference between construction cost and capital cost

29. Cost Estimating Methodology (2 of 7)
Cost estimation considerations (cont)
Clearly understand :
- the type of estimate being prepared
- the assumptions made in preparing the estimate
these should be recorded
- who is responsible to prepare estimate
- who is responsible to review budget
- cost estimating method used
is it appropriate for project phase?
- reviews and comparisons of estimates to be done in consistent manner

30. Cost Estimating Methodology (3 of 7)
Cost estimation considerations (cont)
Predesign Construction Cost Estimating :
- lack of design detail
- establishes realistic estimate of costs and time required
- based on unit costs and process parameters
- Class 5
0 – 2% of design/project defined
-50% to +100% accuracy
- used to develop capital improvement plans, master plans and feasibility studies
- enables comparison of costs associated with alternative treatment processes

31. Cost Estimating Methodology (4 of 7)
Total Process Cost
- sum of cost of constructing all process stages
- cost of each process stage = no. of process modules x cost of construction of individual process modules
Total Construction Cost
- sum of :
total process costs
yard piping (approx 10% of total process costs)
site work landscaping (approx 5% of total process costs)
site electrical and controls (approx 20% of total process costs)
- approx 135% of total process costs
Total Project Cost or Total Capital Cost
total construction costs
engineering costs, legal costs, administrative costs (approx 35% of total construction costs)
- approx 135% of total construction costs

32. Cost Estimating Methodology (5 of 7)
Cost Capacity Curves and Cost Equations

33. Cost Estimating Methodology (6 of 7)
Cost Capacity Curves and Cost Equations (cont)

34. Cost Estimating Methodology (7 of 7)
Cost Capacity Curves and Cost Equations (cont)

35. Unit Conversion Table

36. References
Kawamura, S., 2000, Integrated Design and Operation of Water Treatment Facilities, 2nd Ed., John Wiley and Sons, New York (TH4538K ), pages 62, 502 – 505
McGivney, W.T. and Kawamura, S., 2008, Cost Estimating Manual for Water Treatment Facilities, John Wiley and Sons, New York (TD434M ), entire book
Masters, G.M., 1998, Introduction to Environmental Engineering and Science, Prentice Hall, Upper Saddle River, pages